Pile Design for Downdrag: Examples and Supporting Materials (2024)

Chapter: Appendix I: Design Example 7 - Liquefaction in Gravel Using PileAXL and TZPILE

Previous Chapter: Appendix H: Design Example 6 - Liquefaction in Sand (Pipe Pile) Using ALLCPT and TZPILE
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Suggested Citation: "Appendix I: Design Example 7 - Liquefaction in Gravel Using PileAXL and TZPILE." National Academies of Sciences, Engineering, and Medicine. 2024. Pile Design for Downdrag: Examples and Supporting Materials. Washington, DC: The National Academies Press. doi: 10.17226/27864.

APPENDIX I

Design Example 7 — Liquefaction in Gravel Using PileAXL and TZPILE

Soil profile used for the design example calculation
Figure I1. Soil profile used for the design example calculation.

Design Example 7 is similar to Design Examples 5 and 6. The similarity is associated with the post-liquefaction reconsolidation settlement leading to drag load development in the pile. The difference between Design Example 7 and Design Examples 5 and 6 is that Design Example 7 deals with liquefaction of gravel while Design Examples 5 and 6 dealt with liquefaction of sands. Similar procedures for determining the amount of soil settlement were used; however, the design calculations for gravel are different than the design calculations for sands. Another difference between this design example (Design Example 7) and the previous liquefaction related design examples (Design Examples 5 and 6) is that this design example uses shear wave velocity-based liquefaction-triggering

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Suggested Citation: "Appendix I: Design Example 7 - Liquefaction in Gravel Using PileAXL and TZPILE." National Academies of Sciences, Engineering, and Medicine. 2024. Pile Design for Downdrag: Examples and Supporting Materials. Washington, DC: The National Academies Press. doi: 10.17226/27864.

procedures (Kayen et al. 2013, Rollins et al. 2022) to compute liquefaction-induced settlement and the other design examples used CPT-based settlement procedures (Boulanger and Idriss 2014).

Step 1: Establish soil data

The data for this design example were provided by the Alaska Department of Transportation (Hemstreet, 2014). Specifically, the interpreted soil profile is provided in Figure I1. This figure was developed using the correlations between the AKDOT obtained SPT blow count and the shear wave velocity. Field measured shear wave velocity and design shear wave velocity are also presented in Figure I1. Based on the collected data, the site predominately consists of gravel to a depth of 150 feet with a few interbedded sand and silt layers. Factors required for additional calculations include effective unit weight (γ’), relative density (Dr), and FC are also presented in Figure I1 and tabulated in Table I1.

Table I1. Design soil properties for the Alaska gravel design example.

Material Depth z γ′ φ′ N1,60 σz Vs Es ν Ko Ir qn fs
Gravel 0 - 10 5 120 36 25 1200 735 428634 0.2 0.4 194 120021 161
Gravel 10 - 21 15.5 67 38 50 1937 935 106269 0.3 0.3 271 226386 256
Sand 21 - 30 25.5 55 33 11 2432 709 275908 0.2 0.4 72 140667 328
Gravel 30 - 36 33 65 38 47 2822 973 129277 0.3 0.3 226 300946 373
Silt 36 - 50 43 65 30 10 3732 725 307209 0.1 0.5 61 194674 500
Sand 50 - 65 57.5 63 38 41 4677 993 142671 0.3 0.3 151 405671 619
Gravel 65 - 96 80.5 60 38 29 6537 953 116535 0.3 0.3 88 431575 865
Gravel 96 - 124 110 60 35 16 8217 867 737490 0.2 0.4 51 409767 110
Gravel 12 - 136 130 52 33 10 8841 799 495616 0.2 0.4 35 367109 119
Gravel 13 - 200 168 75 40 60 1364 118 341389 0.3 0.3 113 102991 177
z=Midpoint depth of layer [ft], γ′=Effective unit weight [pcf], φ′=Friction angle [o], N1,60=Corrected SPT blow count [bpf], σz′=Effective vertical stress [psf], Vs=Shear wave velocity [ft/sec], Es=Young’s modulus of the soil, ν=Poisson’s ratio of the soil, K=Lateral earth pressure coefficient, Ir=Rigidity index, qn′=Nominal unit end bearing capacity [psf], fs=Nominal unit side resistance [psf]

The values presented in Figure I1 include correlations between SPT, blow counts, and other parameters (Coduto et al. 2016). These parameters include: the soil modulus, Poisson’s ratio, coefficient of lateral earth pressure at rest, rigidity index, unit bearing capacity (as obtained using bearing capacity factors Nγ*, Nq, Nσ) and nominal unit side resistance. The correlated parameters were calculated using Equations 1 through 9. The Method A and Method B flowcharts, as proposed by the NCHRP 12-116A project team, were followed to complete this design example. The flowcharts are include herein for reference.

V s = 427.29 ( N 60 ) 0.205 Equation 1
N 60 = N 1 , 60 2000 l b f t 2 σ z Equation 2
E s = β o O C R + β 1 N 60 with β o = 100000 p s f , OCR = 1 , β 1 = 24000 p s f Equation 3
v = 0.1 = 0.3 ϕ 25 ° 40 ° 2 5 ° Equation 4
K = ( 1 s i n ϕ ) O C R s i n ϕ Equation 5
I r = E s 2 ( 1 + v ) σ z t a n ϕ Equation 6
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Suggested Citation: "Appendix I: Design Example 7 - Liquefaction in Gravel Using PileAXL and TZPILE." National Academies of Sciences, Engineering, and Medicine. 2024. Pile Design for Downdrag: Examples and Supporting Materials. Washington, DC: The National Academies Press. doi: 10.17226/27864.

Equation 1 from Hananceri and Ulusay (2006),

q n = B γ N γ * + σ z N q * Equation 7
N γ * = 0.6 ( N q * 1 ) t a n ϕ Equation 8
N q * = ( 1 + 2 K ) N σ 3 Equation 9
N σ = 3 3 s i n ϕ e ( 90 ϕ ) π 180 t a n 2 ( 45 + ϕ 2 ) I r 4 s i n ϕ 3 ( 1 + s i n ϕ ) Equation 10
f s = K σ z t a n ϕ f with ϕ f = 0.5 ϕ for smooth steel Equation 11

Equations 2-11 from Coduto et al. (2016)

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Suggested Citation: "Appendix I: Design Example 7 - Liquefaction in Gravel Using PileAXL and TZPILE." National Academies of Sciences, Engineering, and Medicine. 2024. Pile Design for Downdrag: Examples and Supporting Materials. Washington, DC: The National Academies Press. doi: 10.17226/27864.

presentation

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Suggested Citation: "Appendix I: Design Example 7 - Liquefaction in Gravel Using PileAXL and TZPILE." National Academies of Sciences, Engineering, and Medicine. 2024. Pile Design for Downdrag: Examples and Supporting Materials. Washington, DC: The National Academies Press. doi: 10.17226/27864.

presentation

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Suggested Citation: "Appendix I: Design Example 7 - Liquefaction in Gravel Using PileAXL and TZPILE." National Academies of Sciences, Engineering, and Medicine. 2024. Pile Design for Downdrag: Examples and Supporting Materials. Washington, DC: The National Academies Press. doi: 10.17226/27864.

Step 2: Determine soil settlement

Liquefaction-triggering and liquefaction-induced settlements

This shear wave velocity-based example calculation of liquefaction-triggering and liquefaction-induced settlement implements the Rollins et al. (2022) and Kayen et al. (2013) shear wave velocity-based (Vsbased) liquefaction-triggering methods for gravels and sands, respectively, coupled with the Yoshimine et al. (2006) post-liquefaction settlement estimation method. The estimate of post-liquefaction reconsolidation settlement is driven by the factor of safety against liquefaction triggering, FSL. Deterministic liquefaction-triggering calculations methods commonly link initial liquefaction to an excess pore pressure ratio of 100% (and/or cyclic shear strain of 3%) corresponding to FSL = 1.0. However, it is critical to recognize that FSL > 1.0 does not mean that excess pore pressures have not been generated under strong ground motion. Volumetric strains can accumulate within a soil deposit for FSL up to 2.0 as shaking generated excess pore pressures dissipate. Thus, seismic design scenario-based liquefaction-triggering calculations which indicate that liquefaction will not be triggered (i.e., FSL > 1.0) do not justify the omission of reconsolidation settlement calculations when considering adverse effects of strong ground motion on transportation infrastructure.

Discussion of liquefaction susceptibility for gravel-rich soils

The calculation procedure for 1D reconsolidation settlement is directly linked to FSL for soils which are susceptible to liquefaction. Soils which are not susceptible to liquefaction will need to be evaluated for the potential of cyclic softening, as very soft to medium stiff, plastic soils may generate excess pore pressures in the design seismic scenario to result in volumetric strain upon dissipation of excess pore pressures (e.g., Jana and Stuedlein 2021, Dadashiserej et al. 2024). The engineer will need to decide how to judge liquefaction susceptibility. CPTs may encounter significant challenges when conducted in gravel-rich soils; hence, drilling and sampling may offer the sole reliable means to assess whether a particular gravel-rich layer (e.g., clayey gravel) will be susceptible to liquefaction. Atterberg limits conducted on the portion of the sample finer than the #40 sieve should be used to assess liquefaction susceptibility (Stuedlein et al. 2023).

Liquefaction triggering

The factor of safety against liquefaction is computed as the ratio of resistance (i.e., capacity) to demand (loading), in which resistance is represented by the cyclic resistance, CRR, and loading is represented using the cyclic stress ratio, CSR. Owing to the inability to reliably sample many liquefaction-susceptible soils, the triggering calculations typically rely on CRR which are correlated to penetration resistance or shear wave velocity. Shear wave velocity must be corrected to account for the effects of overburden stresses. For liquefaction-triggering evaluations using Vs, the overburden stress-corrected Vs, Vs1, is computed in meters per second (m/s) using:

V s 1 = V s ( P a σ v 0 ) 0.25 Eqn. 12

where Pa = atmospheric pressure (taken as 100 kPa) and σv0 = vertical effective stress at the depth corresponding to Vs.

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Suggested Citation: "Appendix I: Design Example 7 - Liquefaction in Gravel Using PileAXL and TZPILE." National Academies of Sciences, Engineering, and Medicine. 2024. Pile Design for Downdrag: Examples and Supporting Materials. Washington, DC: The National Academies Press. doi: 10.17226/27864.

The standardized cyclic resistance of gravelly soils corresponding to a moment magnitude, Mw, earthquake of 7.5, corresponding to 15 uniform shear stress cycles, N = 15, and one atmosphere of pressure may then be computed using Rollins et al. (2022):

C R R M w = 7.5 , σ v 0 = 1 atm = exp ( 3.88 × 10 7 V s 1 3 1.6 M w ln ( 1 P L P L ) 4.95 ) Eqn. 13

where PL is the probability of liquefaction triggering. Note that the case history database of gravelly soils collected by Rollins et al. (2022) contains few cases where the Vs1 of the critical layer was smaller than 150 m/s. Accordingly, caution should be exercised in applying this Vs-based liquefaction-triggering relationship to gravelly soils with Vs1 < 150 m/s.

The cyclic resistance for a given magnitude earthquake is then scaled from the standardized cyclic resistance using:

C R R M w , σ v 0 = C R R M w = 7.5 , σ v 0 = 1 atm M S F Eqn. 14

where MSF = the magnitude scaling factor. Rollins et al. (2022) present the MSF to be used with their gravelly soil CRR, given by:

M S F = 10.667 exp ( 0.316 M w ) Eqn. 15

which is valid for 5.5 < Mw < 9.0.

The standardized cyclic resistance of sandy soils corresponding to a moment magnitude, Mw, earthquake of 7.5, corresponding to 15 uniform shear stress cycles, N = 15, and one atmosphere of pressure may be computed using (Kayen et al. 2013):

C R R M w = 7.5 , σ v 0 = 1 atm = exp ( 0.0073 V s 1 2.8011 2.6168 ln ( M w ) 0.0099 ln ( σ v 0 ) + 0.0028 F C + 0.4809 Φ 1 ( P L ) 1.946 ) Eqn. 16

where FC = fines content and all other parameters have been defined above. The Rollins et al. (2022) method for gravelly soils does not consider the effect of silty fines on cyclic resistance; nonetheless, sampling is necessary to make assessments of liquefaction susceptibility, and should thus include determinations of FC and the plasticity index of fines-containing soils.

Kayen et al. (2013) suggested that deterministic liquefaction-triggering analyses consider PL = 15% in view of precedent (e.g., Seed and Idriss 1971). The cyclic resistance for a given magnitude earthquake is then scaled from the standardized cyclic resistance using:

C R R M w , σ v 0 = C R R M w = 7.5 , σ v 0 = 1 atm D W F Eqn. 17

where DWF = the duration weighting factor, which serves to relate the duration of earthquakes to their magnitude, and is given by (Kayen et al. 2013):

D W F = 15 M w 1.342 Eqn. 18

which is valid for 5.5 < Mw < 9.0.

A significant difference between the CRR computed using standard penetration tests and CPTs and that computed using Vs is that the overburdens stress correction factor, Kσ, is not used to increase or decrease

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Suggested Citation: "Appendix I: Design Example 7 - Liquefaction in Gravel Using PileAXL and TZPILE." National Academies of Sciences, Engineering, and Medicine. 2024. Pile Design for Downdrag: Examples and Supporting Materials. Washington, DC: The National Academies Press. doi: 10.17226/27864.

the cyclic resistance. Kayen et al. (2013) note that the range in vertical effective overburden stresses for critical layers in the case history database was not sufficiently large to justify development and application of the Kσ correction.

In the Simplified method for liquefaction-triggering evaluation, the effective loading imposed by shear waves is taken equal to 65% of the maximum shear stress, τmax, and is equal to:

C R R M w , σ v 0 = 0.65 τ m a x σ v 0 = 0.65 σ v 0 σ v 0 a m a x g r d Eqn. 19

where σv0= total vertical overburden stress, amax/g = peak ground acceleration at the ground surface as a fraction of the gravitational constant, and rd = shear stress reduction coefficient to account for “flexibility” of the soil column relative to the rigid block model (Seed and Idriss 1971). The Rollins et al. (2022) gravelly soil liquefaction-triggering procedure uses the Idriss and Boulanger (2008) formulation for rd, given by:

r d ( z ) = exp ( α ( z ) + β ( z ) M w ) Eqn. 20

where α(z) and β(z) are given by:

α ( z ) = 1.012 1.126 sin ( z 11.73 + 5.133 ) Eqn. 21
β ( z ) = 0.106 1.118 sin ( z 11.28 + 5.142 ) Eqn. 22

respectively, with z = depth in meters, and the elements encapsulated within the parenthesis are in radians. In contrast, the Kayen et al. (2013) liquefaction-triggering procedure for sandy soils uses a shear stress reduction coefficient given by:

r d ( z ) = ( 1 + 23.013 2.949 a m a x + 0.999 M W + 0.0525 V S , 12 m * 16.258 + 0.201 exp ( 0.341 ( z + 0.0785 V S , 12 m * + 7.586 ) ) ) ( ( 1 + 23.013 2.949 a m a x + 0.999 M W + 0.0525 V S , 12 m * 16.258 + 0.201 exp ( 0.341 ( 0.0785 V S , 12 m * + 7.586 ) ) ) ) Eqn. 23

where Vs,12m = the average Vs in the upper 12.2 m (40 ft). Kayen et al. (2013) note that rd is applicable for z < 20 m.

The factor of safety against liquefaction triggering (i.e., ru = 100%) may then be determined for the depth of interest using:

F S L = C R R M W , σ v 0 C S R M W , σ v 0 Eqn. 24

It is worthwhile to note that there exist other corrections to cyclic resistance than those described above, including corrections to account for soil aging (Andrus et al. 2009), which are particularly useful in Pleistocene deposits, and to account for partial saturation (e.g., Hossein et al. 2013), which are useful in silty sands and nonplastic silts which may exhibit partial saturation below the static groundwater table.

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Suggested Citation: "Appendix I: Design Example 7 - Liquefaction in Gravel Using PileAXL and TZPILE." National Academies of Sciences, Engineering, and Medicine. 2024. Pile Design for Downdrag: Examples and Supporting Materials. Washington, DC: The National Academies Press. doi: 10.17226/27864.

Post-liquefaction reconsolidation settlement

The dissipation of shaking-induced excess pore pressures to result in reconsolidation strains and settlement must be estimated when FSL < 2.0. Several methods are available to estimate seismically-induced reconsolidation settlement (Zhang et al. 2002; Yoshimine et al. 2006). This example considers the Yoshimine et al. (2006) methodology for sands as reformulated by Idriss and Boulanger (2008); however, it is emphasized that this methodology was not developed for gravels or gravel-rich soils. In the Yoshimine et al. (2006) methodology, the amount of volumetric strain in cyclic laboratory test specimens is linked to the relative density of the specimen and the magnitude of excess pore pressure generated during cyclic loading, which is in turn related to the maximum shear strain imposed upon the specimen during loading. Hence, the procedure to estimate reconsolidation settlement from volumetric strain includes the calculation of the limiting and maximum shear strain anticipated for a given soil deposit and seismic event, respectively. The limiting shear strain, γlim, in decimal is given by:

γ l i m = 1.859 ( 1.1 D r ) 3 0 Eqn. 25

where Dr = relative density expressed in decimal. The maximum shear strain, γmax, anticipated under a given design loading scenario is assumed smaller than that necessary to trigger excess pore pressures if FSL 2.0, equal to γlim if FSL ≤ FSα, and:

γ m a x = min ( γ l i m , 0.035 ( 2 F S L ) ( 1 F S α F S L F S α ) ) Eqn. 26

for 2 > FSL > FSα, where FSα is given by:

F S α = 0.032 + 4.7 D r 6 ( D r ) 2 Eqn. 27

with Dr 0.4 when calculating FSα. The volumetric strain at a given depth can then be computed as:

ε v = 1.5 exp ( 2.5 D r ) min ( γ m a x , 0.08 ) Eqn. 28

The increment of settlement associated with the volumetric strain at a given depth, z, may then be computed as:

Δ s ( z ) = ε v Δ z Eqn. 29

where z = the increment in depth pertaining to the measured penetration resistance at a given depth. Thereafter, the cumulative settlement representing the one-dimensional reconsolidation settlement at the ground surface is computed as the sum of incremental settlements from the base of the exploration, z = zmax, as:

S 1 D = z = 0 z = z m z x Δ s ( z ) Eqn. 30

Worked Example

The following example calculation of post-seismic reconsolidation settlement was conducted for a site along the Tok River in Alaska. The subsurface consists of interlayered cohesionless gravel and sand deposits. The stratigraphy includes interlayered gravel, sand, and silt layers. Specifically, from the ground surface to the depth of termination of the borings, the deposit is comprised of layers of gravel (21 feet thick), sand (9 feet thick), gravel (6 feet thick), silt (14 feet thick), sand (15 feet thick), and gravel (at least

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Suggested Citation: "Appendix I: Design Example 7 - Liquefaction in Gravel Using PileAXL and TZPILE." National Academies of Sciences, Engineering, and Medicine. 2024. Pile Design for Downdrag: Examples and Supporting Materials. Washington, DC: The National Academies Press. doi: 10.17226/27864.

31 feet thick). The groundwater is located 10 feet below the ground surface. The seismic hazards driving design centers on two design events: (1) Event 1, PGA=0.3g and Mw=6.2; and (2) Event 2, PGA=0.35g and Mw=7.8. Detailed calculations of the factor of safety against liquefaction and 1D reconsolidation settlement for both events are presented for a depth of 122ft below the ground surface (Table I2). The design values, including the effective unit weight (γ′=60pcf), relative density (Dr=48%), fines content (FC=0%), and shear wave velocity (Vs= 867fps) for the depth presented in the calculations and at other depths are shown in Figure I1. Individual parameters that were calculated for all depths for determination of the post-liquefaction reconsolidation settlement are included in Table I4. At a depth of 122ft, the total and effective stresses are σv0 = 15,088 psf, σ′v0 = 8,037 psf, respectively. Pile lengths of 124ft were considered. This pile length corresponded with the minimum penetration of the abutment piles, as listed on the design plans provided by the Alaska DOT.

The results of the liquefaction settlement analysis for Event 1 and Event 2 are presented in Figure I2a and Figure I2b, respectively. For Event 1, liquefaction triggering was not indicated with FSL > 1.0 for all depths, but 2.85 inches of reconsolidation settlement was predicted due to the dissipation of excess pore pressures which are presumed to have been generated under shaking. For Event 2, liquefaction was indicated for all depths except for the gravel layer from 0 to 10ft and for the sand layer from depths of 52 to 64ft, and soil settlement of 40.1 inches was calculated. For both events, soil settlements were observed to the depth of the dense sand layer (136ft).

The results from calculations for all depths are included in Tables I3 through I7. The parameters associated with the corrected shear wave velocity are included in Table I3. Parameters related to the determination of the factor of safety against liquefaction within gravel using the Rollins et al. (2022) method are presented in Table I4. The results from the Kayen et al. (2013) liquefaction-triggering procedure for sandy soils are included in Table I5 because the entire soil deposit was not only a gravel deposit but also contained sand and silt (as shown previously in Figure I1). The factor of safety values were merged so the appropriate factor of safety was assigned to the appropriate soil type (Rollins et al. (2022) for gravel, Kayen et al. (2013) for sand and silt). The settlement values, as a function of depth using the merged factor of safety values, are presented in Table I6.

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Suggested Citation: "Appendix I: Design Example 7 - Liquefaction in Gravel Using PileAXL and TZPILE." National Academies of Sciences, Engineering, and Medicine. 2024. Pile Design for Downdrag: Examples and Supporting Materials. Washington, DC: The National Academies Press. doi: 10.17226/27864.
Soil settlement and factor of safety against liquefaction for: (a) Event 1, and (b) Event 2. Note: scale change for the cumulative soil settlement (secondary x-axis) between Event 1 and Event 2
Figure I2. Soil settlement and factor of safety against liquefaction for: (a) Event 1, and (b) Event 2. Note: scale change for the cumulative soil settlement (secondary x-axis) between Event 1 and Event 2.
Page 233
Suggested Citation: "Appendix I: Design Example 7 - Liquefaction in Gravel Using PileAXL and TZPILE." National Academies of Sciences, Engineering, and Medicine. 2024. Pile Design for Downdrag: Examples and Supporting Materials. Washington, DC: The National Academies Press. doi: 10.17226/27864.

Table I2. Detailed calculations for determining post-liquefaction soil settlement.

Event 1 – PGA=0.3g, Mw=6.2
Equation Worked Example at Depth of 122 ft Comment
Calculate the overburden corrected shear wave velocity, CRR
V s 1 = V s ( P a σ v 0 ) V s 1 = 867 f p s ( 2 , 088 p s f 8 , 037 p s f ) = 612 f p s = 189 m p s Pa=100 kPa=2088psf
C R R M w = 7.5 , σ v 0 = 1 atm = exp ( 3.88 × 10 7 V s 1 3 16 M w ln ( 1 P L P L ) 4.95 ) C R R M w = 7.5 , σ v 0 = 1 atm = exp ( 3.88 × 10 7 ( 189 m p s 3 ) 16 6.2 ln ( 1 0.15 0.15 ) 4.95 ) PL=0.15
M S F = 10.667 exp ( 0.316 M w ) C R R M w = 7.5 , σ v 0 = 1 atm = 0.16
C R R M w , σ v 0 = C R R M w = 7.5 , σ v 0 = 1 atm M S F M S F = 10.667 exp ( 0.316 6.2 ) = 1.5

C R R M w , σ v 0 = 0.16 1.5 = 0.24

SF equation valid or 5.5 < Mw < 9.0
Calculate the cyclic stress ratio, CSR
α ( z ) = 1.012 1.126 sin ( z 11.73 + 5.133 ) α ( z ) = 1.012 1.126 sin ( 122 ft 3.281 m per ft 11.73 + 5.133 ) = 2.03
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Suggested Citation: "Appendix I: Design Example 7 - Liquefaction in Gravel Using PileAXL and TZPILE." National Academies of Sciences, Engineering, and Medicine. 2024. Pile Design for Downdrag: Examples and Supporting Materials. Washington, DC: The National Academies Press. doi: 10.17226/27864.
β ( z ) = 0.16 1.118 sin ( z 11.28 + 5.142 ) β ( z ) = 0.16 1.118 sin ( 122 ft 3.281 m per ft 11.28 + 5.142 ) = 0.20
r d ( z ) = exp ( α ( z ) + β ( z ) M w ) r d ( z ) = exp ( 2.03 + 0.20 62 ) = 0.47
C S R M w , σ v 0 = 0.65 σ v 0 σ v 0 a m a x g r d C S R M w , σ v 0 = 0.65 15 , 088 psf 8 , 037 psf 0.3 g g 0.47 = 0.17
Calculate the factor of safety against liquefaction, FSL
F S L = C R R M w , σ v 0 C S R M w , σ v 0 F S L = 0.24 0.17 = 1.42 See Figure I2; FSL ≤ 2.0 triggers calculation of volumetric strain and corresponding settlement
Calculate reconsolidation settlement
γ l i m = 1.859 ( 1.1 D r ) 3 0 γ l i m = 1.859 ( 1.1 0.48 ) 3 0 γ l i m = 44 % Dr expressed as a decimal
F S α = 0.032 + 4.7 D r 6 ( D r ) 2 F S α = 0.032 + 4.7 0.48 6 ( 0.48 ) 2 = 0.906 F S α = 0.9524 If Dr ≥ 0.392
If Dr ≥ 0.392
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Suggested Citation: "Appendix I: Design Example 7 - Liquefaction in Gravel Using PileAXL and TZPILE." National Academies of Sciences, Engineering, and Medicine. 2024. Pile Design for Downdrag: Examples and Supporting Materials. Washington, DC: The National Academies Press. doi: 10.17226/27864.
γ m a x = min ( γ m a x , 0.035 ( 2 F S L ) ( 1 F S α F S L F S α ) ) γ m a x = min ( 0.44 , 0.035 ( 2 1.42 ) ( 1 0.906 1.42 0.906 ) )
γ m a x = min ( 0.44 , 0.035 ( 2 1.42 ) ( 1 0.906 1.42 0.906 ) )
γ m a x = min ( 0.44 , 0.038 )
γ m a x = 0.376 %
ε v = 1.5 exp ( 2.5 D r ) min ( γ m a x , 0.08 ) ε v = 1.5 exp ( 2.5 0.48 ) min ( 0.0038 , 0.08 ) ε v = 1.5 exp ( 2.5 0.48 ) ( 0.0038 ) = 0.0017 = 0.17 %
Δ s ( z ) = ε v Δ z Δ s ( z ) = 0.0017 ( 1.0 ft ) 12 in per ft = 0.02 in
S 1 D = z = 0 z = z m a x Δ s ( z ) S1D = 2.85 inches See Figure I2
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Suggested Citation: "Appendix I: Design Example 7 - Liquefaction in Gravel Using PileAXL and TZPILE." National Academies of Sciences, Engineering, and Medicine. 2024. Pile Design for Downdrag: Examples and Supporting Materials. Washington, DC: The National Academies Press. doi: 10.17226/27864.

Table I3. Results from calculations to find corrected shear wave velocity.

Elev z Soil Type γ′ σvo σvo Vs Vs1 FC Comments:
For Event #1 – amax=0.3, Mw=6.2, Elev=Elevation above sea level [t], z=Depth [ft], γ′=Effective unit weight [pcf], σvo=Vertical total stress [psf], σvo′=Vertical effective stress [psf], Vs=Shear wave velocity [fps], Vs1=Overburden corrected shear wave velocity [fps], FC=Fines Content.
1960 0 Gravel 120 0 0 735 - 0
1959 1 Gravel 120 120 120 735 1506 0
1958 2 Gravel 120 240 240 735 1267 0
1957 3 Gravel 120 360 360 735 1144 0
1956 4 Gravel 120 480 480 735 1065 0
1955 5 Gravel 120 600 600 735 1007 0
1954 6 Gravel 120 720 720 735 962 0
1953 7 Gravel 120 840 840 735 926 0
1952 8 Gravel 120 960 960 735 896 0
1951 9 Gravel 120 1080 1080 735 870 0
1950 10 Gravel 67 1209 1147 935 1090 31
1949 11 Gravel 67 1339 1214 935 1074 31
1948 12 Gravel 67 1468 1281 935 1060 31
1947 13 Gravel 67 1598 1348 935 1047 31
1946 14 Gravel 67 1727 1415 935 1034 31
1945 15 Gravel 67 1856 1482 935 1022 31
1944 16 Gravel 67 1986 1549 935 1011 31
1943 17 Gravel 67 2115 1616 935 1000 31
1942 18 Gravel 67 2245 1683 935 990 31
1941 19 Gravel 67 2374 1750 935 980 31
1940 20 Gravel 67 2503 1817 935 971 31
1939 21 Sand 55 2621 1872 709 731 6
1938 22 Sand 55 2738 1927 709 726 6
1937 23 Sand 55 2856 1982 709 721 6
1936 24 Sand 55 2973 2037 709 716 6
1935 25 Sand 55 3090 2092 709 711 6
1934 26 Sand 55 3208 2147 709 706 6
1933 27 Sand 55 3325 2202 709 702 6
1932 28 Sand 55 3443 2257 709 698 6
1931 29 Sand 55 3560 2312 709 693 6
1930 30 Gravel 65 3687 2377 973 945 6
1929 31 Gravel 65 3815 2442 973 939 6
1928 32 Gravel 65 3942 2507 973 933 6
1927 33 Gravel 65 4070 2572 973 927 6
1926 34 Gravel 65 4197 2637 973 921 6
1925 35 Gravel 65 4324 2702 973 915 6
1924 36 Silt 65 4452 2767 725 678 92
1923 37 Silt 65 4579 2832 725 674 92
1922 38 Silt 65 4707 2897 725 670 92
1921 39 Silt 65 4834 2962 725 667 92
1920 40 Silt 65 4961 3027 725 663 92
1919 41 Silt 65 5089 3092 725 659 92
1918 42 Silt 65 5216 3157 725 656 92
1917 43 Silt 65 5344 3222 725 653 92
1916 44 Silt 65 5471 3287 725 649 92
1915 45 Silt 65 5598 3352 725 646 92
1914 46 Silt 65 5726 3417 725 643 92
1913 47 Silt 65 5853 3482 725 640 92
1912 48 Silt 65 5981 3547 725 637 92
1911 49 Silt 65 6108 3612 725 634 92
1910 50 Sand 63 6233 3675 993 865 4
Page 237
Suggested Citation: "Appendix I: Design Example 7 - Liquefaction in Gravel Using PileAXL and TZPILE." National Academies of Sciences, Engineering, and Medicine. 2024. Pile Design for Downdrag: Examples and Supporting Materials. Washington, DC: The National Academies Press. doi: 10.17226/27864.
Elev z Soil Type γ′ σvo σvo Vs Vs1 FC Comments:
See definition of variables on previous page.
1909 51 Sand 63 6359 3738 993 861 4
1908 52 Sand 63 6484 3801 993 858 4
1907 53 Sand 63 6610 3864 993 854 4
1906 54 Sand 63 6735 3927 993 851 4
1905 55 Sand 63 6860 3990 993 847 4
1904 56 Sand 63 6986 4053 993 844 4
1903 57 Sand 63 7111 4116 993 841 4
1902 58 Sand 63 7237 4179 993 838 4
1901 59 Sand 63 7362 4242 993 835 4
1900 60 Sand 63 7487 4305 993 831 4
1899 61 Sand 63 7613 4368 993 828 4
1898 62 Sand 63 7738 4431 993 825 4
1897 63 Sand 63 7864 4494 993 823 4
1896 64 Sand 63 7989 4557 993 820 4
1895 65 Gravel 60 8111 4617 953 784 0
1894 66 Gravel 60 8234 4677 953 782 0
1893 67 Gravel 60 8356 4737 953 779 0
1892 68 Gravel 60 8479 4797 953 777 0
1891 69 Gravel 60 8601 4857 953 774 0
1890 70 Gravel 60 8723 4917 953 772 0
1889 71 Gravel 60 8846 4977 953 770 0
1888 72 Gravel 60 8968 5037 953 767 0
1887 73 Gravel 60 9091 5097 953 765 0
1886 74 Gravel 60 9213 5157 953 763 0
1885 75 Gravel 60 9335 5217 953 761 0
1884 76 Gravel 60 9458 5277 953 758 0
1883 77 Gravel 60 9580 5337 953 756 0
1882 78 Gravel 60 9703 5397 953 754 0
1881 79 Gravel 60 9825 5457 953 752 0
1880 80 Gravel 60 9947 5517 953 750 0
1879 81 Gravel 60 10070 5577 953 748 0
1878 82 Gravel 60 10192 5637 953 746 0
1877 83 Gravel 60 10315 5697 953 744 0
1876 84 Gravel 60 10437 5757 953 742 0
1875 85 Gravel 60 10559 5817 953 740 0
1874 86 Gravel 60 10682 5877 953 738 0
1873 87 Gravel 60 10804 5937 953 736 0
1872 88 Gravel 60 10927 5997 953 734 0
1871 89 Gravel 60 11049 6057 953 733 0
1870 90 Gravel 60 11171 6117 953 731 0
1869 91 Gravel 60 11294 6177 953 729 0
1868 92 Gravel 60 11416 6237 953 727 0
1867 93 Gravel 60 11539 6297 953 726 0
1866 94 Gravel 60 11661 6357 953 724 0
1865 95 Gravel 60 11783 6417 953 722 0
1864 96 Gravel 60 11906 6477 867 655 0
1863 97 Gravel 60 12028 6537 867 654 0
1862 98 Gravel 60 12151 6597 867 652 0
1861 99 Gravel 60 12273 6657 867 651 0
1860 100 Gravel 60 12395 6717 867 650 0
1859 101 Gravel 60 12518 6777 867 648 0
Page 238
Suggested Citation: "Appendix I: Design Example 7 - Liquefaction in Gravel Using PileAXL and TZPILE." National Academies of Sciences, Engineering, and Medicine. 2024. Pile Design for Downdrag: Examples and Supporting Materials. Washington, DC: The National Academies Press. doi: 10.17226/27864.
Elev z Soil Type γ′ σvo σvo Vs Vs1 FC Comments:
See definition of variables on previous page.
1858 102 Gravel 60 12640 6837 867 647 0
1857 103 Gravel 60 12763 6897 867 645 0
1856 104 Gravel 60 12885 6957 867 644 0
1855 105 Gravel 60 13007 7017 867 642 0
1854 106 Gravel 60 13130 7077 867 641 0
1853 107 Gravel 60 13252 7137 867 640 0
1852 108 Gravel 60 13375 7197 867 638 0
1851 109 Gravel 60 13497 7257 867 637 0
1850 110 Gravel 60 13619 7317 867 636 0
1849 111 Gravel 60 13742 7377 867 634 0
1848 112 Gravel 60 13864 7437 867 633 0
1847 113 Gravel 60 13987 7497 867 632 0
1846 114 Gravel 60 14109 7557 867 631 0
1845 115 Gravel 60 14231 7617 867 629 0
1844 116 Gravel 60 14354 7677 867 628 0
1843 117 Gravel 60 14476 7737 867 627 0
1842 118 Gravel 60 14599 7797 867 626 0
1841 119 Gravel 60 14721 7857 867 625 0
1840 120 Gravel 60 14843 7917 867 623 0
1839 121 Gravel 60 14966 7977 867 622 0
1838 122 Gravel 60 15088 8037 867 621 0
1837 123 Gravel 60 15211 8097 867 620 0
1836 124 Gravel 52 15325 8149 799 570 0
1835 125 Gravel 52 15439 8201 799 569 0
1834 126 Gravel 52 15554 8253 799 569 0
1833 127 Gravel 52 15668 8305 799 568 0
1832 128 Gravel 52 15783 8357 799 567 0
1831 129 Gravel 52 15897 8409 799 566 0
1830 130 Gravel 52 16011 8461 799 565 0
1829 131 Gravel 52 16126 8513 799 564 0
1828 132 Gravel 52 16240 8565 799 563 0
1827 133 Gravel 52 16355 8617 799 562 0
1826 134 Gravel 52 16469 8669 799 562 0
1825 135 Gravel 52 16583 8721 799 561 0
1824 136 Gravel 75 16721 8796 1187 831 0
1823 137 Gravel 75 16858 8871 1187 830 0
1822 138 Gravel 75 16996 8946 1187 828 0
1821 139 Gravel 75 17133 9021 1187 826 0
1820 140 Gravel 75 17270 9096 1187 824 0
1819 141 Gravel 75 17408 9171 1187 823 0
1818 142 Gravel 75 17545 9246 1187 821 0
1817 143 Gravel 75 17683 9321 1187 819 0
1816 144 Gravel 75 17820 9396 1187 818 0
1815 145 Gravel 75 17957 9471 1187 816 0
1814 146 Gravel 75 18095 9546 1187 814 0
1813 147 Gravel 75 18232 9621 1187 813 0
1812 148 Gravel 75 18370 9696 1187 811 0
1811 149 Gravel 75 18507 9771 1187 810 0
1810 150 Gravel 75 18644 9846 1187 808 0
Page 239
Suggested Citation: "Appendix I: Design Example 7 - Liquefaction in Gravel Using PileAXL and TZPILE." National Academies of Sciences, Engineering, and Medicine. 2024. Pile Design for Downdrag: Examples and Supporting Materials. Washington, DC: The National Academies Press. doi: 10.17226/27864.

Table I4. Results from calculations to find factor of safety against liquefaction (Rollins et al., 2022).

Elev z α(z) β(z) rd CRR7.5 CRR CSR FSLiq Comments:
For Event #1 – amax=0.3, Mw=6.2, MSF=Magnitude scaling factor=1.5, PL=probability of liquefaction triggering=0.15, Elev=Elevation above sea level [t], z=Depth [ft], rd=Shear stress reduction coefficient, α(z)=Term used to find rd, β(z)=Term used to find rd, CRR7.5 = standardized cyclic resistance corresponding to a moment magnitude earthquake of 7.5, with 15 uniform shear stress cycles, and one atmosphere of pressure, CRR=Cyclic resistance ratio for the magnitude and effective stress of interest, CSR=Cyclic stress ratio for the magnitude and effective stress of interest, FSLiq=Factor of safety against liquefaction.
1960 0 0.02 0.00 1.00 - -
1959 1 0.00 0.00 1.00 1.00 1.50 0.20 2.00
1958 2 -0.01 0.00 1.00 1.00 1.50 0.20 2.00
1957 3 -0.02 0.00 1.00 1.00 1.50 0.19 2.00
1956 4 -0.04 0.00 0.99 1.00 1.50 0.19 2.00
1955 5 -0.05 0.01 0.99 0.92 1.38 0.19 2.00
1954 6 -0.07 0.01 0.98 0.69 1.03 0.19 2.00
1953 7 -0.08 0.01 0.98 0.55 0.83 0.19 2.00
1952 8 -0.10 0.01 0.97 0.47 0.70 0.19 2.00
1951 9 -0.12 0.01 0.97 0.41 0.61 0.19 2.00
1950 10 -0.14 0.02 0.96 1.00 1.50 0.20 2.00
1949 11 -0.16 0.02 0.96 1.00 1.50 0.21 2.00
1948 12 -0.17 0.02 0.95 1.00 1.50 0.21 2.00
1947 13 -0.19 0.02 0.94 1.00 1.50 0.22 2.00
1946 14 -0.22 0.02 0.94 1.00 1.50 0.22 2.00
1945 15 -0.24 0.03 0.93 1.00 1.50 0.23 2.00
1944 16 -0.26 0.03 0.93 0.94 1.41 0.23 2.00
1943 17 -0.28 0.03 0.92 0.87 1.32 0.23 2.00
1942 18 -0.30 0.03 0.91 0.82 1.23 0.24 2.00
1941 19 -0.32 0.04 0.91 0.77 1.16 0.24 2.00
1940 20 -0.35 0.04 0.90 0.73 1.09 0.24 2.00
1939 21 -0.37 0.04 0.89 0.23 0.34 0.24 1.39
1938 22 -0.40 0.04 0.89 0.22 0.33 0.25 1.36
1937 23 -0.42 0.05 0.88 0.22 0.33 0.25 1.32
1936 24 -0.45 0.05 0.87 0.21 0.32 0.25 1.30
1935 25 -0.47 0.05 0.87 0.21 0.32 0.25 1.27
1934 26 -0.50 0.06 0.86 0.21 0.31 0.25 1.25
1933 27 -0.52 0.06 0.85 0.20 0.31 0.25 1.23
1932 28 -0.55 0.06 0.85 0.20 0.30 0.25 1.21
1931 29 -0.58 0.06 0.84 0.20 0.30 0.25 1.19
1930 30 -0.60 0.07 0.83 0.62 0.93 0.25 2.00
1929 31 -0.63 0.07 0.82 0.60 0.90 0.25 2.00
1928 32 -0.66 0.07 0.82 0.57 0.86 0.25 2.00
1927 33 -0.69 0.08 0.81 0.56 0.84 0.25 2.00
1926 34 -0.72 0.08 0.80 0.54 0.81 0.25 2.00
1925 35 -0.74 0.08 0.80 0.52 0.78 0.25 2.00
1924 36 -0.77 0.09 0.79 0.19 0.29 0.25 1.15
1923 37 -0.80 0.09 0.78 0.19 0.28 0.25 1.14
1922 38 -0.83 0.09 0.77 0.19 0.28 0.25 1.14
1921 39 -0.86 0.10 0.77 0.18 0.28 0.24 1.13
1920 40 -0.89 0.10 0.76 0.18 0.27 0.24 1.12
1919 41 -0.92 0.10 0.75 0.18 0.27 0.24 1.12
1918 42 -0.95 0.11 0.75 0.18 0.27 0.24 1.11
1917 43 -0.98 0.11 0.74 0.18 0.26 0.24 1.11
1916 44 -1.00 0.11 0.73 0.17 0.26 0.24 1.10
1915 45 -1.03 0.11 0.72 0.17 0.26 0.24 1.10
1914 46 -1.06 0.12 0.72 0.17 0.26 0.23 1.10
1913 47 -1.09 0.12 0.71 0.17 0.26 0.23 1.10
1912 48 -1.12 0.12 0.70 0.17 0.25 0.23 1.09
1911 49 -1.15 0.13 0.70 0.17 0.25 0.23 1.09
1910 50 -1.18 0.13 0.69 0.40 0.60 0.23 2.00
Page 240
Suggested Citation: "Appendix I: Design Example 7 - Liquefaction in Gravel Using PileAXL and TZPILE." National Academies of Sciences, Engineering, and Medicine. 2024. Pile Design for Downdrag: Examples and Supporting Materials. Washington, DC: The National Academies Press. doi: 10.17226/27864.
Elev z α(z) β(z) rd CRR7.5 CRR CSR FSLiq Comments:
See definition of variables on previous page.
1909 51 -1.21 0.13 0.68 0.39 0.59 0.23 2.00
1908 52 -1.24 0.14 0.68 0.39 0.58 0.23 2.00
1907 53 -1.27 0.14 0.67 0.38 0.57 0.22 2.00
1906 54 -1.29 0.14 0.67 0.37 0.56 0.22 2.00
1905 55 -1.32 0.15 0.66 0.37 0.55 0.22 2.00
1904 56 -1.35 0.15 0.65 0.36 0.54 0.22 2.00
1903 57 -1.38 0.15 0.65 0.36 0.53 0.22 2.00
1902 58 -1.41 0.15 0.64 0.35 0.53 0.22 2.00
1901 59 -1.43 0.16 0.63 0.34 0.52 0.21 2.00
1900 60 -1.46 0.16 0.63 0.34 0.51 0.21 2.00
1899 61 -1.49 0.16 0.62 0.34 0.50 0.21 2.00
1898 62 -1.51 0.17 0.62 0.33 0.50 0.21 2.00
1897 63 -1.54 0.17 0.61 0.33 0.49 0.21 2.00
1896 64 -1.56 0.17 0.61 0.32 0.48 0.21 2.00
1895 65 -1.59 0.17 0.60 0.28 0.42 0.21 2.00
1894 66 -1.61 0.18 0.59 0.27 0.41 0.20 2.00
1893 67 -1.64 0.18 0.59 0.27 0.41 0.20 2.00
1892 68 -1.66 0.18 0.58 0.27 0.40 0.20 2.00
1891 69 -1.69 0.18 0.58 0.27 0.40 0.20 2.00
1890 70 -1.71 0.19 0.57 0.26 0.40 0.20 1.99
1889 71 -1.73 0.19 0.57 0.26 0.39 0.20 1.99
1888 72 -1.76 0.19 0.57 0.26 0.39 0.20 1.98
1887 73 -1.78 0.19 0.56 0.26 0.39 0.19 1.98
1886 74 -1.80 0.20 0.56 0.25 0.38 0.19 1.97
1885 75 -1.82 0.20 0.55 0.25 0.38 0.19 1.97
1884 76 -1.84 0.20 0.55 0.25 0.38 0.19 1.97
1883 77 -1.86 0.20 0.54 0.25 0.37 0.19 1.96
1882 78 -1.88 0.20 0.54 0.25 0.37 0.19 1.96
1881 79 -1.90 0.20 0.53 0.24 0.37 0.19 1.95
1880 80 -1.91 0.21 0.53 0.24 0.36 0.19 1.95
1879 81 -1.93 0.21 0.53 0.24 0.36 0.19 1.95
1878 82 -1.95 0.21 0.52 0.24 0.36 0.18 1.94
1877 83 -1.96 0.21 0.52 0.24 0.36 0.18 1.94
1876 84 -1.98 0.21 0.52 0.24 0.35 0.18 1.94
1875 85 -1.99 0.21 0.51 0.23 0.35 0.18 1.93
1874 86 -2.01 0.22 0.51 0.23 0.35 0.18 1.93
1873 87 -2.02 0.22 0.51 0.23 0.35 0.18 1.92
1872 88 -2.03 0.22 0.50 0.23 0.34 0.18 1.92
1871 89 -2.05 0.22 0.50 0.23 0.34 0.18 1.92
1870 90 -2.06 0.22 0.50 0.23 0.34 0.18 1.91
1869 91 -2.07 0.22 0.50 0.22 0.34 0.18 1.91
1868 92 -2.08 0.22 0.49 0.22 0.34 0.18 1.91
1867 93 -2.09 0.22 0.49 0.22 0.33 0.18 1.90
1866 94 -2.09 0.22 0.49 0.22 0.33 0.17 1.90
1865 95 -2.10 0.22 0.49 0.22 0.33 0.17 1.89
1864 96 -2.11 0.22 0.48 0.18 0.27 0.17 1.54
1863 97 -2.12 0.22 0.48 0.18 0.27 0.17 1.54
1862 98 -2.12 0.22 0.48 0.18 0.26 0.17 1.53
1861 99 -2.13 0.22 0.48 0.18 0.26 0.17 1.53
1860 100 -2.13 0.22 0.48 0.17 0.26 0.17 1.53
1859 101 -2.13 0.22 0.48 0.17 0.26 0.17 1.53
Page 241
Suggested Citation: "Appendix I: Design Example 7 - Liquefaction in Gravel Using PileAXL and TZPILE." National Academies of Sciences, Engineering, and Medicine. 2024. Pile Design for Downdrag: Examples and Supporting Materials. Washington, DC: The National Academies Press. doi: 10.17226/27864.
Elev z α(z) β(z) rd CRR7.5 CRR CSR FSLiq Comments:
See definition of variables on previous page.
1858 102 -2.14 0.22 0.47 0.17 0.26 0.17 1.52
1857 103 -2.14 0.22 0.47 0.17 0.26 0.17 1.52
1856 104 -2.14 0.22 0.47 0.17 0.26 0.17 1.52
1855 105 -2.14 0.22 0.47 0.17 0.26 0.17 1.51
1854 106 -2.14 0.22 0.47 0.17 0.26 0.17 1.51
1853 107 -2.14 0.22 0.47 0.17 0.26 0.17 1.51
1852 108 -2.13 0.22 0.47 0.17 0.25 0.17 1.50
1851 109 -2.13 0.22 0.47 0.17 0.25 0.17 1.50
1850 110 -2.13 0.22 0.47 0.17 0.25 0.17 1.49
1849 111 -2.12 0.22 0.47 0.17 0.25 0.17 1.49
1848 112 -2.12 0.22 0.47 0.17 0.25 0.17 1.48
1847 113 -2.11 0.22 0.47 0.17 0.25 0.17 1.48
1846 114 -2.11 0.22 0.47 0.17 0.25 0.17 1.47
1845 115 -2.10 0.21 0.47 0.17 0.25 0.17 1.47
1844 116 -2.09 0.21 0.47 0.16 0.25 0.17 1.46
1843 117 -2.08 0.21 0.47 0.16 0.25 0.17 1.45
1842 118 -2.07 0.21 0.47 0.16 0.25 0.17 1.45
1841 119 -2.06 0.21 0.47 0.16 0.25 0.17 1.44
1840 120 -2.05 0.21 0.47 0.16 0.24 0.17 1.43
1839 121 -2.04 0.21 0.47 0.16 0.24 0.17 1.43
1838 122 -2.03 0.20 0.47 0.16 0.24 0.17 1.42
1837 123 -2.01 0.20 0.47 0.16 0.24 0.17 1.41
1836 124 -2.00 0.20 0.47 0.14 0.22 0.17 1.25
1835 125 -1.99 0.20 0.47 0.14 0.22 0.17 1.24
1834 126 -1.97 0.20 0.47 0.14 0.21 0.17 1.24
1833 127 -1.95 0.19 0.47 0.14 0.21 0.17 1.23
1832 128 -1.94 0.19 0.48 0.14 0.21 0.18 1.22
1831 129 -1.92 0.19 0.48 0.14 0.21 0.18 1.21
1830 130 -1.90 0.19 0.48 0.14 0.21 0.18 1.21
1829 131 -1.89 0.19 0.48 0.14 0.21 0.18 1.20
1828 132 -1.87 0.18 0.48 0.14 0.21 0.18 1.19
1827 133 -1.85 0.18 0.48 0.14 0.21 0.18 1.18
1826 134 -1.83 0.18 0.49 0.14 0.21 0.18 1.17
1825 135 -1.81 0.18 0.49 0.14 0.21 0.18 1.17
1824 136 -1.79 0.17 0.49 0.34 0.51 0.18 2.00
1823 137 -1.76 0.17 0.49 0.34 0.51 0.18 2.00
1822 138 -1.74 0.17 0.50 0.33 0.50 0.18 2.00
1821 139 -1.72 0.17 0.50 0.33 0.50 0.18 2.00
1820 140 -1.70 0.16 0.50 0.33 0.50 0.19 2.00
1819 141 -1.67 0.16 0.51 0.33 0.49 0.19 2.00
1818 142 -1.65 0.16 0.51 0.32 0.49 0.19 2.00
1817 143 -1.63 0.15 0.51 0.32 0.48 0.19 2.00
1816 144 -1.60 0.15 0.51 0.32 0.48 0.19 2.00
1815 145 -1.58 0.15 0.52 0.32 0.48 0.19 2.00
1814 146 -1.55 0.15 0.52 0.31 0.47 0.19 2.00
1813 147 -1.52 0.14 0.53 0.31 0.47 0.19 2.00
1812 148 -1.50 0.14 0.53 0.31 0.47 0.20 2.00
1811 149 -1.47 0.14 0.53 0.31 0.46 0.20 2.00
1810 150 -1.44 0.13 0.54 0.31 0.46 0.20 2.00
Page 242
Suggested Citation: "Appendix I: Design Example 7 - Liquefaction in Gravel Using PileAXL and TZPILE." National Academies of Sciences, Engineering, and Medicine. 2024. Pile Design for Downdrag: Examples and Supporting Materials. Washington, DC: The National Academies Press. doi: 10.17226/27864.

Table I5. Results from calculations to find factor of safety against liquefaction (Kayen et al., 2013).

Elev z rd CSR CRR7.5 CRR FSLiq Comments:
For Event #1 – amax=0.3, Mw=6.2, DFW=Duration weighting factor=1.29, PL=probability of liquefaction triggering=0.15, Elev=Elevation above sea level [t], z=Depth [ft], rd=Shear stress reduction coefficient, CSR=Cyclic stress ratio for the magnitude and effective stress of interest, CRR7.5 = standardized cyclic resistance corresponding to a moment magnitude earthquake of 7.5, with 15 uniform shear stress cycles, and one atmosphere of pressure, CRR=Cyclic resistance ratio for the magnitude and effective stress of interest, FSLiq=Factor of safety against liquefaction.
1960 0
1959 1 1.00 0.19 1.00 1.29 2.00
1958 2 1.00 0.19 1.00 1.29 2.00
1957 3 1.00 0.19 1.00 1.29 2.00
1956 4 1.00 0.19 1.00 1.29 2.00
1955 5 1.00 0.19 1.00 1.29 2.00
1954 6 1.00 0.19 1.00 1.29 2.00
1953 7 1.00 0.19 1.00 1.29 2.00
1952 8 1.00 0.19 1.00 1.29 2.00
1951 9 1.00 0.19 1.00 1.29 2.00
1950 10 1.00 0.20 1.00 1.29 2.00
1949 11 1.00 0.21 1.00 1.29 2.00
1948 12 0.99 0.22 1.00 1.29 2.00
1947 13 0.99 0.23 1.00 1.29 2.00
1946 14 0.99 0.24 1.00 1.29 2.00
1945 15 0.99 0.24 1.00 1.29 2.00
1944 16 0.99 0.25 1.00 1.29 2.00
1943 17 0.99 0.25 1.00 1.29 2.00
1942 18 0.99 0.26 1.00 1.29 2.00
1941 19 0.99 0.26 1.00 1.29 2.00
1940 20 0.99 0.26 1.00 1.29 2.00
1939 21 0.98 0.27 0.49 0.63 2.00
1938 22 0.98 0.27 0.47 0.61 2.00
1937 23 0.98 0.28 0.45 0.58 2.00
1936 24 0.98 0.28 0.44 0.56 2.00
1935 25 0.98 0.28 0.42 0.54 1.94
1934 26 0.97 0.28 0.41 0.53 1.86
1933 27 0.97 0.29 0.39 0.51 1.78
1932 28 0.97 0.29 0.38 0.49 1.72
1931 29 0.96 0.29 0.37 0.48 1.66
1930 30 0.96 0.29 1.00 1.29 2.00
1929 31 0.96 0.29 1.00 1.29 2.00
1928 32 0.95 0.29 1.00 1.29 2.00
1927 33 0.95 0.29 1.00 1.29 2.00
1926 34 0.94 0.29 1.00 1.29 2.00
1925 35 0.94 0.29 1.00 1.29 2.00
1924 36 0.93 0.29 0.38 0.49 1.67
1923 37 0.93 0.29 0.37 0.47 1.63
1922 38 0.92 0.29 0.36 0.46 1.59
1921 39 0.91 0.29 0.35 0.45 1.55
1920 40 0.91 0.29 0.34 0.44 1.52
1919 41 0.90 0.29 0.33 0.43 1.49
1918 42 0.89 0.29 0.33 0.42 1.47
1917 43 0.89 0.29 0.32 0.41 1.44
1916 44 0.88 0.29 0.31 0.40 1.42
1915 45 0.87 0.28 0.31 0.40 1.40
1914 46 0.86 0.28 0.30 0.39 1.38
1913 47 0.86 0.28 0.30 0.38 1.36
1912 48 0.85 0.28 0.29 0.38 1.34
1911 49 0.84 0.28 0.29 0.37 1.33
1910 50 0.84 0.28 1.00 1.29 2.00
Page 243
Suggested Citation: "Appendix I: Design Example 7 - Liquefaction in Gravel Using PileAXL and TZPILE." National Academies of Sciences, Engineering, and Medicine. 2024. Pile Design for Downdrag: Examples and Supporting Materials. Washington, DC: The National Academies Press. doi: 10.17226/27864.
Elev z rd CSR CRR7.5 CRR FSLiq Comments:See definition of variables on previous page.
1909 51 0.83 0.27 1.00 1.29 2.00
1908 52 0.82 0.27 1.00 1.29 2.00
1907 53 0.81 0.27 1.00 1.29 2.00
1906 54 0.81 0.27 1.00 1.29 2.00
1905 55 0.80 0.27 1.00 1.29 2.00
1904 56 0.80 0.27 1.00 1.29 2.00
1903 57 0.79 0.27 1.00 1.29 2.00
1902 58 0.78 0.26 1.00 1.29 2.00
1901 59 0.78 0.26 1.00 1.29 2.00
1900 60 0.77 0.26 1.00 1.29 2.00
1899 61 0.77 0.26 1.00 1.29 2.00
1898 62 0.76 0.26 1.00 1.29 2.00
1897 63 0.76 0.26 1.00 1.29 2.00
1896 64 0.76 0.26 1.00 1.29 2.00
1895 65 0.75 0.26 0.75 0.96 2.00
1894 66 0.75 0.26 0.73 0.94 2.00
1893 67 0.75 0.26 0.71 0.92 2.00
1892 68 0.74 0.26 0.70 0.90 2.00
1891 69 0.74 0.26 0.68 0.89 2.00
1890 70 0.74 0.26 0.67 0.87 2.00
1889 71 0.74 0.26 0.66 0.85 2.00
1888 72 0.74 0.26 0.64 0.83 2.00
1887 73 0.73 0.26 0.63 0.82 2.00
1886 74 0.73 0.26 0.62 0.80 2.00
1885 75 0.73 0.25 0.61 0.79 2.00
1884 76 0.73 0.25 0.60 0.77 2.00
1883 77 0.73 0.25 0.59 0.76 2.00
1882 78 0.73 0.25 0.58 0.75 2.00
1881 79 0.73 0.25 0.57 0.74 2.00
1880 80 0.73 0.25 0.56 0.72 2.00
1879 81 0.72 0.25 0.55 0.71 2.00
1878 82 0.72 0.26 0.54 0.70 2.00
1877 83 0.72 0.26 0.53 0.69 2.00
1876 84 0.72 0.26 0.52 0.68 2.00
1875 85 0.72 0.26 0.52 0.67 2.00
1874 86 0.72 0.26 0.51 0.66 2.00
1873 87 0.72 0.26 0.50 0.65 2.00
1872 88 0.72 0.26 0.49 0.64 2.00
1871 89 0.72 0.26 0.49 0.63 2.00
1870 90 0.72 0.26 0.48 0.62 2.00
1869 91 0.72 0.26 0.47 0.61 2.00
1868 92 0.72 0.26 0.47 0.61 2.00
1867 93 0.72 0.26 0.46 0.60 2.00
1866 94 0.72 0.26 0.46 0.59 2.00
1865 95 0.72 0.26 0.45 0.58 2.00
1864 96 0.72 0.26 0.28 0.37 1.43
1863 97 0.72 0.26 0.28 0.36 1.41
1862 98 0.72 0.26 0.28 0.36 1.40
1861 99 0.72 0.26 0.28 0.36 1.38
1860 100 0.72 0.26 0.27 0.35 1.37
1859 101 0.72 0.26 0.27 0.35 1.36
Page 244
Suggested Citation: "Appendix I: Design Example 7 - Liquefaction in Gravel Using PileAXL and TZPILE." National Academies of Sciences, Engineering, and Medicine. 2024. Pile Design for Downdrag: Examples and Supporting Materials. Washington, DC: The National Academies Press. doi: 10.17226/27864.
Elev z rd CSR CRR7.5 CRR FSLiq Comments:
See definition of variables on previous page.
1858 102 0.72 0.26 0.27 0.35 1.34
1857 103 0.72 0.26 0.27 0.34 1.33
1856 104 0.72 0.26 0.26 0.34 1.32
1855 105 0.72 0.26 0.26 0.34 1.31
1854 106 0.72 0.26 0.26 0.34 1.29
1853 107 0.72 0.26 0.26 0.33 1.28
1852 108 0.72 0.26 0.26 0.33 1.27
1851 109 0.72 0.26 0.25 0.33 1.26
1850 110 0.72 0.26 0.25 0.33 1.25
1849 111 0.72 0.26 0.25 0.32 1.24
1848 112 0.72 0.26 0.25 0.32 1.23
1847 113 0.72 0.26 0.25 0.32 1.22
1846 114 0.72 0.26 0.24 0.32 1.21
1845 115 0.72 0.26 0.24 0.31 1.20
1844 116 0.72 0.26 0.24 0.31 1.19
1843 117 0.72 0.26 0.24 0.31 1.18
1842 118 0.72 0.26 0.24 0.31 1.17
1841 119 0.72 0.26 0.24 0.30 1.16
1840 120 0.72 0.26 0.23 0.30 1.15
1839 121 0.72 0.26 0.23 0.30 1.14
1838 122 0.72 0.26 0.23 0.30 1.14
1837 123 0.72 0.26 0.23 0.30 1.13
1836 124 0.72 0.26 0.18 0.23 0.87
1835 125 0.72 0.26 0.18 0.23 0.86
1834 126 0.72 0.26 0.17 0.23 0.86
1833 127 0.72 0.26 0.17 0.22 0.85
1832 128 0.72 0.26 0.17 0.22 0.85
1831 129 0.72 0.26 0.17 0.22 0.84
1830 130 0.72 0.26 0.17 0.22 0.84
1829 131 0.72 0.26 0.17 0.22 0.83
1828 132 0.72 0.26 0.17 0.22 0.83
1827 133 0.72 0.27 0.17 0.22 0.83
1826 134 0.72 0.27 0.17 0.22 0.82
1825 135 0.72 0.27 0.17 0.22 0.82
1824 136 0.72 0.27 1.00 1.29 2.00
1823 137 0.72 0.27 1.00 1.29 2.00
1822 138 0.72 0.27 1.00 1.29 2.00
1821 139 0.72 0.27 1.00 1.29 2.00
1820 140 0.72 0.27 1.00 1.29 2.00
1819 141 0.72 0.27 1.00 1.29 2.00
1818 142 0.72 0.27 1.00 1.29 2.00
1817 143 0.72 0.27 1.00 1.29 2.00
1816 144 0.72 0.26 1.00 1.29 2.00
1815 145 0.72 0.26 0.99 1.28 2.00
1814 146 0.72 0.26 0.98 1.26 2.00
1813 147 0.72 0.26 0.96 1.25 2.00
1812 148 0.72 0.26 0.95 1.23 2.00
1811 149 0.72 0.26 0.93 1.21 2.00
1810 150 0.72 0.26 0.92 1.19 2.00
Page 245
Suggested Citation: "Appendix I: Design Example 7 - Liquefaction in Gravel Using PileAXL and TZPILE." National Academies of Sciences, Engineering, and Medicine. 2024. Pile Design for Downdrag: Examples and Supporting Materials. Washington, DC: The National Academies Press. doi: 10.17226/27864.

Table I6. Results from calculations to find soil settlement (Boulanger and Idriss, 2008).

Elev z Dr γlim γmax εv δ Σδ Comments: For Event #1 – amax=0.3, Mw=6.2, z=Depth [ft], FSα =Factor of Safety, γlim =Limiting shear strain, γmax =Maximum shear strain, εv =Volumetric strain, δ = ∆s = Incremental soil settlement [in], Σδ = s1D = Cumulative soil settlement from bottom of soil profile to top of soil profile [in].

Applicable for gravel and sand (merged FS based on Rollins et al. 2022 for gravel or Kayen et al. 2013 for sand and silt).
1960 0
1959 1 67 0.488 15 0.000 0.00 0.00 2.85
1958 2 67 0.488 15 0.000 0.00 0.00 2.85
1957 3 67 0.488 15 0.000 0.00 0.00 2.85
1956 4 67 0.488 15 0.000 0.00 0.00 2.85
1955 5 67 0.488 15 0.000 0.00 0.00 2.85
1954 6 67 0.488 15 0.000 0.00 0.00 2.85
1953 7 67 0.488 15 0.000 0.00 0.00 2.85
1952 8 67 0.488 15 0.000 0.00 0.00 2.85
1951 9 67 0.488 15 0.000 0.00 0.00 2.85
1950 10 99 -1.196 0 0.000 0.00 0.00 2.85
1949 11 99 -1.196 0 0.000 0.00 0.00 2.85
1948 12 99 -1.196 0 0.000 0.00 0.00 2.85
1947 13 99 -1.196 0 0.000 0.00 0.00 2.85
1946 14 99 -1.196 0 0.000 0.00 0.00 2.85
1945 15 99 -1.196 0 0.000 0.00 0.00 2.85
1944 16 99 -1.196 0 0.000 0.00 0.00 2.85
1943 17 99 -1.196 0 0.000 0.00 0.00 2.85
1942 18 99 -1.196 0 0.000 0.00 0.00 2.85
1941 19 99 -1.196 0 0.000 0.00 0.00 2.85
1940 20 99 -1.196 0 0.000 0.00 0.00 2.85
1939 21 46 0.924 49 0.000 0.00 0.00 2.85
1938 22 46 0.924 49 0.000 0.00 0.00 2.85
1937 23 46 0.924 49 0.000 0.00 0.00 2.85
1936 24 46 0.924 49 0.000 0.00 0.00 2.85
1935 25 46 0.924 49 0.017 0.01 0.00 2.85
1934 26 46 0.924 49 0.041 0.02 0.00 2.85
1933 27 46 0.924 49 0.067 0.03 0.00 2.85
1932 28 46 0.924 49 0.094 0.04 0.01 2.84
1931 29 46 0.924 49 0.124 0.06 0.01 2.84
1930 30 94 -0.852 1 0.000 0.00 0.00 2.83
1929 31 94 -0.852 1 0.000 0.00 0.00 2.83
1928 32 94 -0.852 1 0.000 0.00 0.00 2.83
1927 33 94 -0.852 1 0.000 0.00 0.00 2.83
1926 34 94 -0.852 1 0.000 0.00 0.00 2.83
1925 35 94 -0.852 1 0.000 0.00 0.00 2.83
1924 36 42 0.948 58 0.085 0.04 0.01 2.83
1923 37 42 0.948 58 0.101 0.05 0.01 2.82
1922 38 42 0.948 58 0.118 0.06 0.01 2.82
1921 39 42 0.948 58 0.135 0.07 0.01 2.81
1920 40 42 0.948 58 0.153 0.08 0.01 2.80
1919 41 42 0.948 58 0.171 0.09 0.01 2.79
1918 42 42 0.948 58 0.189 0.10 0.01 2.78
1917 43 42 0.948 58 0.208 0.11 0.01 2.77
1916 44 42 0.948 58 0.227 0.12 0.01 2.76
1915 45 42 0.948 58 0.246 0.13 0.02 2.74
1914 46 42 0.948 58 0.265 0.14 0.02 2.73
1913 47 42 0.948 58 0.284 0.15 0.02 2.71
1912 48 42 0.948 58 0.304 0.16 0.02 2.69
1911 49 42 0.948 58 0.323 0.17 0.02 2.67
1910 50 84 -0.254 3 0.000 0.00 0.00 2.65
Page 246
Suggested Citation: "Appendix I: Design Example 7 - Liquefaction in Gravel Using PileAXL and TZPILE." National Academies of Sciences, Engineering, and Medicine. 2024. Pile Design for Downdrag: Examples and Supporting Materials. Washington, DC: The National Academies Press. doi: 10.17226/27864.
Elev z Dr γlim γmax εv δ Σδ Comments:
See definition of variables on previous page.

Applicable for gravel and sand (merged FS based on Rollins et al. 2022 for gravel or Kayen et al. 2013 for sand and silt).
1909 51 84 -0.254 3 0.000 0.00 0.00 2.65
1908 52 84 -0.254 3 0.000 0.00 0.00 2.65
1907 53 84 -0.254 3 0.000 0.00 0.00 2.65
1906 54 84 -0.254 3 0.000 0.00 0.00 2.65
1905 55 84 -0.254 3 0.000 0.00 0.00 2.65
1904 56 84 -0.254 3 0.000 0.00 0.00 2.65
1903 57 84 -0.254 3 0.000 0.00 0.00 2.65
1902 58 84 -0.254 3 0.000 0.00 0.00 2.65
1901 59 84 -0.254 3 0.000 0.00 0.00 2.65
1900 60 84 -0.254 3 0.000 0.00 0.00 2.65
1899 61 84 -0.254 3 0.000 0.00 0.00 2.65
1898 62 84 -0.254 3 0.000 0.00 0.00 2.65
1897 63 84 -0.254 3 0.000 0.00 0.00 2.65
1896 64 84 -0.254 3 0.000 0.00 0.00 2.65
1895 65 68 0.454 14 0.000 0.00 0.00 2.65
1894 66 68 0.454 14 0.000 0.00 0.00 2.65
1893 67 68 0.454 14 0.000 0.00 0.00 2.65
1892 68 68 0.454 14 0.000 0.00 0.00 2.65
1891 69 68 0.454 14 0.002 0.00 0.00 2.65
1890 70 68 0.454 14 0.008 0.00 0.00 2.65
1889 71 68 0.454 14 0.015 0.00 0.00 2.65
1888 72 68 0.454 14 0.021 0.01 0.00 2.65
1887 73 68 0.454 14 0.027 0.01 0.00 2.65
1886 74 68 0.454 14 0.033 0.01 0.00 2.65
1885 75 68 0.454 14 0.038 0.01 0.00 2.65
1884 76 68 0.454 14 0.044 0.01 0.00 2.65
1883 77 68 0.454 14 0.049 0.01 0.00 2.65
1882 78 68 0.454 14 0.054 0.01 0.00 2.64
1881 79 68 0.454 14 0.059 0.02 0.00 2.64
1880 80 68 0.454 14 0.064 0.02 0.00 2.64
1879 81 68 0.454 14 0.068 0.02 0.00 2.64
1878 82 68 0.454 14 0.073 0.02 0.00 2.64
1877 83 68 0.454 14 0.078 0.02 0.00 2.63
1876 84 68 0.454 14 0.083 0.02 0.00 2.63
1875 85 68 0.454 14 0.088 0.02 0.00 2.63
1874 86 68 0.454 14 0.093 0.03 0.00 2.63
1873 87 68 0.454 14 0.098 0.03 0.00 2.62
1872 88 68 0.454 14 0.103 0.03 0.00 2.62
1871 89 68 0.454 14 0.108 0.03 0.00 2.62
1870 90 68 0.454 14 0.113 0.03 0.00 2.61
1869 91 68 0.454 14 0.119 0.03 0.00 2.61
1868 92 68 0.454 14 0.125 0.03 0.00 2.61
1867 93 68 0.454 14 0.131 0.04 0.00 2.60
1866 94 68 0.454 14 0.137 0.04 0.00 2.60
1865 95 68 0.454 14 0.143 0.04 0.00 2.59
1864 96 48 0.906 44 0.242 0.11 0.01 2.59
1863 97 48 0.906 44 0.244 0.11 0.01 2.57
1862 98 48 0.906 44 0.245 0.11 0.01 2.56
1861 99 48 0.906 44 0.247 0.11 0.01 2.55
1860 100 48 0.906 44 0.250 0.11 0.01 2.53
1859 101 48 0.906 44 0.252 0.11 0.01 2.52
Page 247
Suggested Citation: "Appendix I: Design Example 7 - Liquefaction in Gravel Using PileAXL and TZPILE." National Academies of Sciences, Engineering, and Medicine. 2024. Pile Design for Downdrag: Examples and Supporting Materials. Washington, DC: The National Academies Press. doi: 10.17226/27864.
Elev z Dr γlim γmax εv δ Σδ Comments:
See definition of variables on previous page.

Applicable for gravel and sand (merged FS based on Rollins et al. 2022 for gravel or Kayen et al. 2013 for sand and silt).
1858 102 48 0.906 44 0.255 0.12 0.01 2.51
1857 103 48 0.906 44 0.258 0.12 0.01 2.49
1856 104 48 0.906 44 0.261 0.12 0.01 2.48
1855 105 48 0.906 44 0.264 0.12 0.01 2.47
1854 106 48 0.906 44 0.268 0.12 0.01 2.45
1853 107 48 0.906 44 0.272 0.12 0.01 2.44
1852 108 48 0.906 44 0.276 0.12 0.01 2.42
1851 109 48 0.906 44 0.280 0.13 0.02 2.41
1850 110 48 0.906 44 0.285 0.13 0.02 2.39
1849 111 48 0.906 44 0.291 0.13 0.02 2.38
1848 112 48 0.906 44 0.296 0.13 0.02 2.36
1847 113 48 0.906 44 0.302 0.14 0.02 2.34
1846 114 48 0.906 44 0.308 0.14 0.02 2.33
1845 115 48 0.906 44 0.315 0.14 0.02 2.31
1844 116 48 0.906 44 0.322 0.15 0.02 2.29
1843 117 48 0.906 44 0.330 0.15 0.02 2.28
1842 118 48 0.906 44 0.338 0.15 0.02 2.26
1841 119 48 0.906 44 0.346 0.16 0.02 2.24
1840 120 48 0.906 44 0.356 0.16 0.02 2.22
1839 121 48 0.906 44 0.365 0.17 0.02 2.20
1838 122 48 0.906 44 0.376 0.170 0.020 2.18
1837 123 48 0.906 44 0.386 0.17 0.02 2.16
1836 124 37 -0.952 72 2.325 1.38 0.17 2.14
1835 125 37 -0.952 72 2.354 1.40 0.17 1.98
1834 126 37 -0.952 72 2.383 1.42 0.17 1.81
1833 127 37 -0.952 72 2.413 1.44 0.17 1.64
1832 128 37 -0.952 72 2.445 1.45 0.17 1.47
1831 129 37 -0.952 72 2.477 1.47 0.18 1.29
1830 130 37 -0.952 72 2.511 1.49 0.18 1.11
1829 131 37 -0.952 72 2.545 1.51 0.18 0.93
1828 132 37 -0.952 72 2.581 1.54 0.18 0.75
1827 133 37 -0.952 72 2.618 1.56 0.19 0.57
1826 134 37 -0.952 72 2.655 1.58 0.19 0.38
1825 135 37 -0.952 72 2.694 1.60 0.19 0.19
1824 136 86 -0.364 3 0.000 0.00 0.00 0.00
1823 137 86 -0.364 3 0.000 0.00 0.00 0.00
1822 138 86 -0.364 3 0.000 0.00 0.00 0.00
1821 139 86 -0.364 3 0.000 0.00 0.00 0.00
1820 140 86 -0.364 3 0.000 0.00 0.00 0.00
1819 141 86 -0.364 3 0.000 0.00 0.00 0.00
1818 142 86 -0.364 3 0.000 0.00 0.00 0.00
1817 143 86 -0.364 3 0.000 0.00 0.00 0.00
1816 144 86 -0.364 3 0.000 0.00 0.00 0.00
1815 145 86 -0.364 3 0.000 0.00 0.00 0.00
1814 146 86 -0.364 3 0.000 0.00 0.00 0.00
1813 147 86 -0.364 3 0.000 0.00 0.00 0.00
1812 148 86 -0.364 3 0.000 0.00 0.00 0.00
1811 149 86 -0.364 3 0.000 0.00 0.00 0.00
1810 150 86 -0.364 3 0.000 0.00 0.00 0.00
Page 248
Suggested Citation: "Appendix I: Design Example 7 - Liquefaction in Gravel Using PileAXL and TZPILE." National Academies of Sciences, Engineering, and Medicine. 2024. Pile Design for Downdrag: Examples and Supporting Materials. Washington, DC: The National Academies Press. doi: 10.17226/27864.

Step 3: Establish pile data

Design-specific information, obtained from Hemstreet (2014), for the piles (type, size, length, modulus) that were to be installed within Embankment 1 for the Tok River Bridge No. 0603 and the design earthquake are presented in Table I7. The pile investigated was a 124-foot long 18inch diameter open ended steel pipe pile with a 0.5-inch wall thickness.

Table I7. Pile and earthquake information from Hemstreet (2014).

Anticipated Liquefaction Settlement 6-8 [inches]
Anticipated Nominal Drag load 75 [kips]
Anticipated Driving Resistance 600 [kips]
Pile Material Steel
Pile Shape Open Ended Pipe Pile
Pile Thickness 0.5 [inches]
Pile Area 27.49 [sq. inches]
Pile Embedded Length 124 [ft]
Pile Modulus 29000 [ksi]
Strength I Factored Load 300 [kips]
Nominal Resistance 460 [kips]
Resistance Factor 0.65
Top Load on Pile 0 [kips]
Number of Pile Increments 61
Ground Water Table Depth 10 [ft]
Design Earthquake Sources Denali Fault Western Part Totshunda Fault
Attenuation Relationships Abrahamson and Silva (2008) Boore and Atkinson (2008) Campbell and Bozorgnia (2008)

Step 4: Compute incremental side resistance

The unit side resistance and incremental side resistance were identified using the Innovative Geotechnics (2023) PileAXL program (Version 2.5). As mentioned in the description of the previous design examples that used the Innovative Geotechnics programs, the programs only accept metric units. Therefore, many of the parameters were converted between imperial units and metric units. The input data, within the PileAXL program, are shown in Figures I3 through I11. The pile section properties and analysis options are shown in Figures I3 and I4.

Establishment of pile section data within the PileAXL software program
Figure I3. Establishment of pile section data within the PileAXL software program.
Page 249
Suggested Citation: "Appendix I: Design Example 7 - Liquefaction in Gravel Using PileAXL and TZPILE." National Academies of Sciences, Engineering, and Medicine. 2024. Pile Design for Downdrag: Examples and Supporting Materials. Washington, DC: The National Academies Press. doi: 10.17226/27864.
Establishment of the pile length, number of increments, top load, and design code
Figure I4. Establishment of the pile length, number of increments, top load, and design code.
Partial factors of safety used within the PileAXL software program
Figure I5. Partial factors of safety used within the PileAXL software program.

The working load design approach is presented in Figure I5. As with all of the other design examples, all of the used loads were unfactored loads and all of the determined resistances were unfactored resistances. Therefore, the factors of safety values in Figure I5 were set to unity. The different soil layer materials were created using the Material Sets, as shown in Figure I6. Each of the materials was created then modified by selecting the Edit button to enable input of the various soil parameters (material type, material name, total unit weight, friction angle, and coefficient of lateral earth pressure) as shown in Figure I7. Additional parameters included in the driven pile material input (bearing capacity factor, limiting skin resistance, and limiting unit end bearing) were automatically populated by selection on the appropriate material using the (…) button that was located next to the bearing capacity factor input box. The friction angle and soil type were used to select the appropriate soil description (Figure I8).

Page 250
Suggested Citation: "Appendix I: Design Example 7 - Liquefaction in Gravel Using PileAXL and TZPILE." National Academies of Sciences, Engineering, and Medicine. 2024. Pile Design for Downdrag: Examples and Supporting Materials. Washington, DC: The National Academies Press. doi: 10.17226/27864.
Define - Soil Materials within the PileAXL software program
Figure I6. Define - Soil Materials within the PileAXL software program.

Upon completion of the creation of the soil materials, the soil material were assigned to soil layers (Figure I9). The nine soil layers that were created using the Define – Soil Layers – Edit buttons are presented in Figure I10. All of the required information was available within the program at the end of the definition of soil layers stage (Figure I11). The program was then executed to obtain the desired results that are presented in Figure I12 and Table I8. The incremental side resistance is presented as ∆Q in Table I8. These values were obtained by differencing the ultimate total side resistance (ULS Qs) for each sublayer as a function of depth.

Step 5: Develop a depth-dependent load profile

A depth-dependent load profile was output directly from the program. The depth depended load profile was obtained by adding the unfactored top load (149.5tons) to each reported in the ultimate total side resistance (ULS Qs) column. Although a depth-dependent load profile is not presented, this profile can be developed by plotting each depth-dependent load (Q) against the corresponding depth (z).

Step 6: Compute end bearing resistance; develop a depth resistance profile

The depth-dependent resistance profile was developed by adding the output end bearing resistance to the side resistance. The profile is developed from the bottom of the pile to the top of the pile; the incremental side resistance will cumulate from the bottom of the pile to the top of the pile. Although a depth-dependent resistance profile is not presented, this profile can be developed by plotting each depth-dependent load (R) against the corresponding depth (z).

Step 7: Develop a depth-dependent combined load profile

The depth-dependent combined load-resistance curve is presented as Figure I13. This curve was developed by plotting the minimum of load or resistance as a function of depth against the corresponding depth. For this curve, a maximum load in the pile of 282 tons was observed.

Step 8: Identify the location of the neutral plane from the combined load-resistance curve

As observed in Figure I13, the neutral plane is observed to occur at the location of maximum load in the pile. This location is identified as occurring at 99.99ft below the ground surface. For this analysis, the open ended pile was assumed to be plugged.

Step 9: Calculate the amount of drag load in the pile

The 129 tons drag load was calculated for the pile. This drag load was obtained by subtracting the unfactored top load (149.5 tons) from the maximum load in the pile (282 tons). As previously mentioned in Steps 7 and 8, the maximum load in the pile occurred at the neutral plane (at a depth of 99.99 feet below the ground surface).

Page 251
Suggested Citation: "Appendix I: Design Example 7 - Liquefaction in Gravel Using PileAXL and TZPILE." National Academies of Sciences, Engineering, and Medicine. 2024. Pile Design for Downdrag: Examples and Supporting Materials. Washington, DC: The National Academies Press. doi: 10.17226/27864.

Steps 10 and 11: Calculate the toe settlement, elastic compression, and geotechncial resistance

Steps 10 and 11 of the NCHRP12-116A Method A flowchart were combined because the values are presented using the load-settlement curve. The load-settlement curve that was developed using output from the PileAXL software is shown in Figure I14 and the results are tabulated in Table I9. From Figure I14, the pile head settlement was calculated to be 1.54in and the geotechnical resistance was calculated to be 337tons. The elastic compression of the pile was calculated using the depth-dependent loads from the combined load-resistance curve. The amount of cumulative elastic compression was determined by summing the individual elastic compression values from the bottom of the pile to the top of the pile. By subtracting the cumulative elastic compression in the pile, as a function of depth, a toe settlement of 0.786in was obtained for Event 1 (a=0.3, Mw=6.2). The geotechnical resistance was determined to be sufficient, although the amount of settlement at the pile toe was determined to be excessive. The pile was not tipped into rock, so Step 12 of the NCHRP12-116A Method A flowchart was then completed.

Step 12: Determine the location and settlement of the neutral plane (from the soil settlement-pilesettlement curve)

The pile settlement mentioned in Steps 10 and 11 was plotted on the same plot as the soil settlement obtained in Step 2. As shown in Figure I15, the pile settlement and the soil settlement curves do not cross. Therefore, the location of the neutral plane cannot be determined using the load-settlement–soil-settlement curve. If the two pile settlement and soil settlement curves do not cross than no drag load should develop but significant downdrag will develop. The evaluated pile (124ft long) was too short and should be extended to prevent the significant downdrag. Although the pile is able to maintain the design load, as the downdrag develops the pile toe moves downward creating a serviceability issue.

The design check of the neutral plane locations, which were obtained in Step 8 and in Step 12, being within 5 feet of each other was not met because the neutral plane was not able to be identified in the pile-settlement–soil-settlement curve in Step 12. Therefore, Steps 3 through 12 were repeated by following the NCHRP12-116A Method A flowchart. A pile length of 136 feet was evaluated because no post-liquefaction reconsolidation settlement was observed below this depth. The key figures developed by using a pile length of 136 feet are presented in Figures I16 through I18.

Step 13: Perform limit state checks

From these Figures I16 through I18, the neutral plane locations that were obtained from the combined load-resistance curve and the soil settlement-pile settlement curve were 105.99ft and 131ft. The design check of the neutral plane locations, which were obtained in Step 8 and in Step 12, being within 5 feet of each other was not met because the difference in the neutral plane locations was greater than 5 feet. Step 13 of the NCHRP12-116A Method A flowchart could not be completed due to the difference in neutral plane locations being greater than 5 feet. Therefore, a difference pile geometry should be selected or Method B should be attempted. As with Design Example 6, due to the large difference modifications to the pile geometry are not expected to alter the difference in the locations of the neutral plane. Therefore, for this design example, it is recommended that the Method B flowchart be followed.

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Suggested Citation: "Appendix I: Design Example 7 - Liquefaction in Gravel Using PileAXL and TZPILE." National Academies of Sciences, Engineering, and Medicine. 2024. Pile Design for Downdrag: Examples and Supporting Materials. Washington, DC: The National Academies Press. doi: 10.17226/27864.
Define – Soil Materials – Edit within the PileAXL software program for the different materials
Figure I7. Define – Soil Materials – Edit within the PileAXL software program for the different materials.
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Suggested Citation: "Appendix I: Design Example 7 - Liquefaction in Gravel Using PileAXL and TZPILE." National Academies of Sciences, Engineering, and Medicine. 2024. Pile Design for Downdrag: Examples and Supporting Materials. Washington, DC: The National Academies Press. doi: 10.17226/27864.
Define-Soil Materials – Edit – (…) button next to the bearing capacity factor input box
Figure I8. Define-Soil Materials – Edit – (…) button next to the bearing capacity factor input box.
Define – Soil Layers within the PileAXL software program
Figure I9. Define – Soil Layers within the PileAXL software program.
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Suggested Citation: "Appendix I: Design Example 7 - Liquefaction in Gravel Using PileAXL and TZPILE." National Academies of Sciences, Engineering, and Medicine. 2024. Pile Design for Downdrag: Examples and Supporting Materials. Washington, DC: The National Academies Press. doi: 10.17226/27864.
Define – Soil Layers – Edit within the PileAXL software program for the different soil layers
Figure I10. Define – Soil Layers – Edit within the PileAXL software program for the different soil layers.
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Suggested Citation: "Appendix I: Design Example 7 - Liquefaction in Gravel Using PileAXL and TZPILE." National Academies of Sciences, Engineering, and Medicine. 2024. Pile Design for Downdrag: Examples and Supporting Materials. Washington, DC: The National Academies Press. doi: 10.17226/27864.
Main window of Pile AXL after inputting all of the required data
Figure I11. Main window of Pile AXL after inputting all of the required data.
PileAXL output data window after analyzing the data
Figure I12. PileAXL output data window after analyzing the data.
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Suggested Citation: "Appendix I: Design Example 7 - Liquefaction in Gravel Using PileAXL and TZPILE." National Academies of Sciences, Engineering, and Medicine. 2024. Pile Design for Downdrag: Examples and Supporting Materials. Washington, DC: The National Academies Press. doi: 10.17226/27864.

Table I8. PileAXL output for the Tok River Bridge Abutment 1 piles (converted to imperial units).

Depth ULS fs ULS Qs ULS Qb ∆Q Q R min(Q,R) δpile Comments:
ULS fs = Ultimate unit side shear (PileAXL output), ULS Qs = Ultimate total side resistance (PileAXL output), ULS Qb = Ultimate bearing resistance (PileAXL output), ∆Q =incremental side resistance (Excel calculation), Q = cumulative load in the pile (Excel calculation), R= resistance from soil surrounding pile; resistance values are calculated at the top of each sublayer (Excel calculation), min(Q,R) = minimum of Q and R for each depth (Excel calculation).
[ft] [tsf] [tons] [tons] [tons] [tons] [tons] [tons] [in]
0.00 0.0000 0.0000 0.0000 0.0000 149.5000 411.6266 149.5000 1.540
2.00 0.0357 0.1684 10.6007 0.1684 149.6684 411.6266 149.6684 1.531
4.00 0.0715 0.6736 21.2014 0.5052 150.1736 411.4583 150.1736 1.523
6.00 0.0835 1.4040 31.8022 0.7304 150.9040 410.9531 150.9040 1.514
8.00 0.0835 2.1912 42.4029 0.7872 151.6912 410.2227 151.6912 1.505
10.00 0.0835 2.9784 53.0036 0.7872 152.4784 409.4355 152.4784 1.496
12.00 0.1253 3.9624 58.8319 0.9840 153.4624 408.6482 153.4624 1.487
14.00 0.1253 5.1433 64.6412 1.1808 154.6433 407.6642 154.6433 1.478
16.00 0.1253 6.3241 70.4505 1.1808 155.8241 406.4834 155.8241 1.469
18.00 0.1253 7.5049 76.2598 1.1808 157.0049 405.3025 157.0049 1.460
20.00 0.1253 8.6858 82.0691 1.1808 158.1858 404.1217 158.1858 1.451
22.00 0.1671 10.0634 69.8799 1.3776 159.5634 402.9409 159.5634 1.441
24.00 0.1671 11.6379 73.6816 1.5744 161.1379 401.5632 161.1379 1.432
26.00 0.1671 13.2123 77.4832 1.5744 162.7123 399.9888 162.7123 1.423
28.00 0.1671 14.7867 81.2849 1.5745 164.2867 398.4143 164.2867 1.413
30.00 0.1880 16.4596 106.3620 1.6728 165.9596 396.8399 165.9596 1.403
32.00 0.1880 18.2308 111.9858 1.7713 167.7308 395.1671 167.7308 1.394
34.00 0.1880 20.0021 117.6095 1.7713 169.5021 393.3958 169.5021 1.384
36.00 0.1880 21.7733 123.2332 1.7712 171.2733 391.6245 171.2733 1.374
37.99 0.2506 23.8398 103.0855 2.0665 173.3398 389.8533 173.3398 1.364
39.99 0.2506 26.2015 107.5845 2.3617 175.7015 387.7868 175.7015 1.353
41.99 0.2506 28.5631 112.0835 2.3617 178.0631 385.4252 178.0631 1.343
43.99 0.2506 30.9248 116.5825 2.3617 180.4248 383.0635 180.4248 1.333
45.99 0.2506 33.2865 121.0815 2.3617 182.7865 380.7018 182.7865 1.322
47.99 0.2506 35.6481 125.5804 2.3617 185.1481 378.3402 185.1481 1.311
49.99 0.3133 38.3050 162.5888 2.6569 187.8050 375.9785 187.8050 1.300
51.99 0.3133 41.2571 168.0438 2.9521 190.7571 373.3216 190.7571 1.289
53.99 0.3133 44.2092 173.4988 2.9521 193.7092 370.3695 193.7092 1.278
55.99 0.3133 47.1613 178.9538 2.9521 196.6613 367.4174 196.6613 1.266
57.99 0.3133 50.1134 184.4088 2.9521 199.6134 364.4654 199.6134 1.255
59.99 0.3133 53.0654 189.8638 2.9521 202.5654 361.5133 202.5654 1.243
61.99 0.3133 56.0175 195.3188 2.9521 205.5175 358.5612 205.5175 1.231
63.99 0.3133 58.9696 200.7738 2.9521 208.4696 355.6091 208.4696 1.219
65.99 0.4282 62.4629 206.0956 3.4933 211.9629 352.6570 211.9629 1.207
67.99 0.4282 66.4974 211.2919 4.0345 215.9974 349.1637 215.9974 1.194
69.99 0.4282 70.5319 216.4882 4.0345 220.0319 345.1292 220.0319 1.181
71.99 0.4282 74.5665 221.4368 4.0345 224.0665 341.0947 224.0665 1.168
73.99 0.4282 78.6010 221.4368 4.0345 228.1010 337.0602 228.1010 1.155
75.99 0.4282 82.6355 221.4368 4.0345 232.1355 333.0257 232.1355 1.141
77.99 0.4282 86.6700 221.4368 4.0345 236.1700 328.9911 236.1700 1.128
79.99 0.4282 90.7045 221.4368 4.0345 240.2045 324.9566 240.2045 1.114
81.99 0.4282 94.7390 221.4368 4.0345 244.2390 320.9221 244.2390 1.099
83.99 0.4282 98.7736 221.4368 4.0345 248.2736 316.8876 248.2736 1.085
85.99 0.4282 102.8081 221.4368 4.0345 252.3081 312.8531 252.3081 1.070
87.99 0.4282 106.8426 221.4368 4.0345 256.3426 308.8186 256.3426 1.055
89.99 0.4282 110.8771 221.4368 4.0345 260.3771 304.7840 260.3771 1.040
91.99 0.4282 114.9116 221.4368 4.0345 264.4116 300.7495 264.4116 1.025
93.99 0.4282 118.9461 221.4368 4.0345 268.4461 296.7150 268.4461 1.009
95.99 0.4282 122.9807 221.4368 4.0345 272.4807 292.6805 272.4807 0.993
97.99 0.5535 127.6056 221.4368 4.6249 277.1056 288.6460 277.1056 0.977
99.99 0.5535 132.8209 221.4368 5.2153 282.3209 284.0210 282.3209 0.961
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Suggested Citation: "Appendix I: Design Example 7 - Liquefaction in Gravel Using PileAXL and TZPILE." National Academies of Sciences, Engineering, and Medicine. 2024. Pile Design for Downdrag: Examples and Supporting Materials. Washington, DC: The National Academies Press. doi: 10.17226/27864.
Depth ULS fs ULS Qs ULS Qb ∆Q Q R min(Q,R) δpile Comments:
See definition of variables on previous page.
101.99 0.5535 138.0363 221.4368 5.2153 287.5363 278.8057 278.8057 0.945
103.99 0.5535 143.2516 221.4368 5.2153 292.7516 273.5903 273.5903 0.929
105.99 0.5535 148.4670 221.4368 5.2153 297.9670 268.3750 268.3750 0.913
107.99 0.5535 153.6823 221.4368 5.2153 303.1823 263.1596 263.1596 0.898
109.98 0.5535 158.8977 221.4368 5.2154 308.3977 257.9443 257.9443 0.883
111.98 0.5535 164.1130 221.4368 5.2153 313.6130 252.7289 252.7289 0.868
113.98 0.5535 169.3284 221.4368 5.2153 318.8284 247.5136 247.5136 0.854
115.98 0.5535 174.5437 221.4368 5.2153 324.0437 242.2982 242.2982 0.840
117.98 0.5535 179.7591 221.4368 5.2153 329.2591 237.0829 237.0829 0.826
119.98 0.5535 184.9744 221.4368 5.2153 334.4744 231.8675 231.8675 0.812
121.98 0.5535 190.1898 221.4368 5.2153 339.6898 226.6522 226.6522 0.799
123.98 0.5535 195.4051 221.4368 5.2153 344.9051 221.4368 221.4368 0.786
Minimum of load or resistance values at each depth, as a function of depth for a 124ft long pile. Note: presented using imperial units
Figure I13. Minimum of load or resistance values at each depth, as a function of depth for a 124ft long pile. Note: presented using imperial units.
Load-settlement curve from PileAXL output in imperial units for a 124ft long pile. The unfactored top load applied to pile in PileAXL program to develop the curve was 3000kN
Figure I14. Load-settlement curve from PileAXL output in imperial units for a 124ft long pile. The unfactored top load applied to pile in PileAXL program to develop the curve was 3000kN.
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Suggested Citation: "Appendix I: Design Example 7 - Liquefaction in Gravel Using PileAXL and TZPILE." National Academies of Sciences, Engineering, and Medicine. 2024. Pile Design for Downdrag: Examples and Supporting Materials. Washington, DC: The National Academies Press. doi: 10.17226/27864.

Table I9. Load-settlement curve data for a 124ft long pile. Note: presented using imperial units.

δhead Qhead Comments:
δhead=Pile head movement, Qhead=Pile head load
[in] [tons]
0.000 0.000
0.065 33.721
0.132 67.443
0.212 101.164
0.307 134.885
0.415 168.607
0.534 202.328
0.668 236.049
0.847 269.771
1.094 303.492
1.522 337.213
Pile and soil settlement as a function of depth. Note: presented using imperial units
Figure I15. Pile and soil settlement as a function of depth. Note: presented using imperial units.
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Suggested Citation: "Appendix I: Design Example 7 - Liquefaction in Gravel Using PileAXL and TZPILE." National Academies of Sciences, Engineering, and Medicine. 2024. Pile Design for Downdrag: Examples and Supporting Materials. Washington, DC: The National Academies Press. doi: 10.17226/27864.
Minimum of load or resistance values at each depth, as a function of depth for 136ft pile
Figure I16. Minimum of load or resistance values at each depth, as a function of depth for 136ft pile.
Pile and soil settlement as a function of depth. Note: presented using imperial units
Figure I17. Pile and soil settlement as a function of depth. Note: presented using imperial units.
Page 260
Suggested Citation: "Appendix I: Design Example 7 - Liquefaction in Gravel Using PileAXL and TZPILE." National Academies of Sciences, Engineering, and Medicine. 2024. Pile Design for Downdrag: Examples and Supporting Materials. Washington, DC: The National Academies Press. doi: 10.17226/27864.
Load-settlement curve from PileAXL output in imperial units for a 136ft long pile. The unfactored top load applied to pile in PileAXL program to develop the curve was 4000kN
Figure I18. Load-settlement curve from PileAXL output in imperial units for a 136ft long pile. The unfactored top load applied to pile in PileAXL program to develop the curve was 4000kN.

Table I10. Load-settlement curve data for a 136ft long pile. Note: presented using imperial units.

δhead Qhead Comments:
δhead=Pile head movement, Qhead=Pile head load
[in] [tons]
0.000 0.000
0.087 44.962
0.184 89.924
0.308 134.885
0.456 179.847
0.624 224.809
0.816 269.771
1.093 314.733
1.556 359.694
2.235 404.656
3.285 449.618

Method B: TZPILE design calculations with PileAXL input

For ease of use, t-z and Q-w curves that were “Generated by the program” were used. The use of these curves allows for soil layer data to be input instead of t-z and Q-w curves. These data are presented in Step 1. Steps 2 and 3 for Method B are identical to those listed above for Method A. Therefore, these steps are not repeated in this section.

Step 1: Establish soil data

The soil data, as input into the TZPILE software program are presented in Figure I19. The ultimate unit skin resistance and ultimate unit tip resistance for each of the identified layers was obtained from the PileAXL output. As discussed previously in other design example problems, the TZPILE program uses units of inches and pounds, so the output from the PileAXL program were converted from metric units to imperial units prior to input into the TZPILE program. Also, the unit weight profile and undrained shear strength had to be converted from units of lb/ft3 and lb/ft2 to lb/in3 and lb/in2, respectively.

Steps 2 and 3: Determine soil settlement and establish pile data

The soil settlement and pile data used in Method B are the same as those used in Method A. These data, as used in the TZPILE program, are included as Figures I20 and I21. The pile data include axial stiffness.

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Suggested Citation: "Appendix I: Design Example 7 - Liquefaction in Gravel Using PileAXL and TZPILE." National Academies of Sciences, Engineering, and Medicine. 2024. Pile Design for Downdrag: Examples and Supporting Materials. Washington, DC: The National Academies Press. doi: 10.17226/27864.
Soil properties in TZPILE
Figure I19. Soil properties in TZPILE.
Soil settlement properties in TZPILE
Figure I20. Soil settlement properties in TZPILE.
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Suggested Citation: "Appendix I: Design Example 7 - Liquefaction in Gravel Using PileAXL and TZPILE." National Academies of Sciences, Engineering, and Medicine. 2024. Pile Design for Downdrag: Examples and Supporting Materials. Washington, DC: The National Academies Press. doi: 10.17226/27864.
Pile properties in TZPILE
Figure I21. Pile properties in TZPILE.

Step 4: Select t-z models and q-z model

As mentioned previously and shown in Figure I19, “Generated by the program” t-z and Q-w curves were used. Specifically, Driven Pile in Sand (API) curves were used for each layer. The selection of using curves that were generated by the program instead of user defined was for ease of use. The use of user defined gravel curves for the gravel layers may be more appropriate; however, no user defined t-z curves specifically for gravel currently exist.

Step 5: Iterate toe movement to obtain unfactored top load

As shown in Figure I22, the toe movement was iterated to obtain the unfactored top load. Specifically, a toe movement of 2.114in resulted in the unfactored top load of 298.5kips. Steps 6 through 8: Develop depth-dependent combined load inpile, identify the location of the neutral plane from thecombined load-resistance curve, and calculate the amount ofdrag load in the pile

Iteration of toe movements
Figure I22. Iteration of toe movements.

The depth-dependent combined load and resistance curve that was developed using the TZPILE program is presented in Figure I23 and reported in Table I11. From Figure I23, the neutral plane occurs at a depth

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Suggested Citation: "Appendix I: Design Example 7 - Liquefaction in Gravel Using PileAXL and TZPILE." National Academies of Sciences, Engineering, and Medicine. 2024. Pile Design for Downdrag: Examples and Supporting Materials. Washington, DC: The National Academies Press. doi: 10.17226/27864.

of 119.0ft. Based on the results, the maximum load in the pile is 514.1 kips, resulting in a drag load of 215.6kips.

Table I11. Results from TZPILE, as obtained by using PileAXL input and additional spreadsheet post-processing calculations.

z Min(Q,R) δp Comments:
z=Depth [ft], Min(Q,R)=Load used to develop combination curve to identify the location of the neutral plane, δp =pile settlement.
1 294.1 2.887
3 294.0 2.878
5 293.8 2.870
7 293.7 2.861
9 293.6 2.852
11 293.6 2.843
13 293.8 2.834
15 294.1 2.825
17 294.7 2.816
19 295.5 2.808
21 296.5 2.799
23 297.7 2.790
25 299.2 2.781
27 300.9 2.772
29 302.9 2.763
31 305.0 2.753
33 307.2 2.744
35 309.6 2.735
37 312.2 2.726
39 315.0 2.716
41 317.9 2.707
43 320.7 2.697
45 323.3 2.687
47 325.5 2.678
49 326.5 2.668
51 326.5 2.658
53 326.4 2.648
55 327.0 2.638
57 328.4 2.628
59 330.5 2.618
61 333.2 2.608
63 336.7 2.598
65 340.7 2.588
67 345.3 2.578
69 350.4 2.567
71 355.9 2.557
73 361.8 2.546
75 368.1 2.535
77 374.6 2.524
79 381.3 2.512
81 388.3 2.501
83 395.5 2.489
85 402.8 2.477
87 410.3 2.465
89 418.0 2.452
91 425.7 2.440
z Min(Q,R) δp
103 473.0 2.358
105 480.4 2.344
107 487.4 2.329
109 494.0 2.315
111 500.1 2.300
113 505.4 2.285
115 509.8 2.269
117 512.9 2.254
119 514.1 2.238
121 513.2 2.223
123 509.9 2.208
125 502.5 2.192
127 491.9 2.177
129 481.2 2.163
131 470.4 2.148
133 459.4 2.134
135 448.4 2.121
Combined load-resistance curve from TZPILE, as obtained by using PileAXL inpu
Figure I23. Combined load-resistance curve from TZPILE, as obtained by using PileAXL inpu and additional spreadsheet post-processing calculations.
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Suggested Citation: "Appendix I: Design Example 7 - Liquefaction in Gravel Using PileAXL and TZPILE." National Academies of Sciences, Engineering, and Medicine. 2024. Pile Design for Downdrag: Examples and Supporting Materials. Washington, DC: The National Academies Press. doi: 10.17226/27864.
93 433.6 2.427
95 441.6 2.414
97 449.6 2.400
99 457.6 2.386
101 465.4 2.373

Step 9: Calculate the geotechnical resistance of the pile

The geotechnical resistance was determined in TZPILE by repeating Step 5 of the Method B flowchart. For these analyses, the soil settlement was neglected by turning off the Include Down-Drag (negative Skin Friction) toggle within TZPILE (Figure I24) and by also selecting the Load Method as User-Specified Tip Movements (Figure I25). Specifically, multiple tip movements (Figure I26) were evaluated to develop a load-settlement curve (Figure I27 and Table I12). This curve represents the pile head axial load and the pile head settlement. Two specific tip movements were included during the creation of the load-settlement curve; tip movements corresponding with a tip movement of 0.0138in, which was calculated when the unfactored design load (298.5kips) was obtained at the top of the pile, and a tip movement of 0.05B (0.9in). The geotechnical resistance was identified as 573kips and the pile head movement required to mobilize the geotechnical resistance was 0.95in.

Include Down-Drag (negative Skin Frictioin) toggle unselected in TZPILE
Figure I24. Include Down-Drag (negative Skin Frictioin) toggle unselected in TZPILE.
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Suggested Citation: "Appendix I: Design Example 7 - Liquefaction in Gravel Using PileAXL and TZPILE." National Academies of Sciences, Engineering, and Medicine. 2024. Pile Design for Downdrag: Examples and Supporting Materials. Washington, DC: The National Academies Press. doi: 10.17226/27864.
User-Specified Tip Movement Load Method selection in TZPILE
Figure I25. User-Specified Tip Movement Load Method selection in TZPILE.
Range of tip movements used to create the load-displacement curve
Figure I26. Range of tip movements used to create the load-displacement curve.
TZPILE obtained load-settlement curve with nominal downward load resistance identified
Figure I27. TZPILE obtained load-settlement curve with nominal downward load resistance identified.

Table I12. TZPILE obtained load-settlement curve.

Pile Head Load, P, [kips] Pile Head Movement, δ [in.]
0.0 0.000
246.7 0.291
298.0 0.370
361.9 0.478
436.8 0.618
481.6 0.710
501.1 0.756
518.1 0.797
533.4 0.836
547.3 0.872
559.9 0.907
571.3 0.939
645.8 1.189
678.8 1.357
700.0 1.500
721.2 1.643
742.4 1.787
763.6 1.930
780.7 2.065
792.6 2.190

Step 10: Identify the location and settlement of the neutral plane (from the soil settlement-pilesettlement curve)

The amount of elastic compression within the pile was automatically calculated in the TZPILE software program. These automatically generated values simplify efforts compared to the hand calculation that

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Suggested Citation: "Appendix I: Design Example 7 - Liquefaction in Gravel Using PileAXL and TZPILE." National Academies of Sciences, Engineering, and Medicine. 2024. Pile Design for Downdrag: Examples and Supporting Materials. Washington, DC: The National Academies Press. doi: 10.17226/27864.

was presented in Design Example 1. Just like Design Example 1, the TZPILE elastic compression calculations are based on the amount of calculated load within the pile at each incremental depth. The calculated soil settlements were tabulated and shown previously in Table I6 and Figure I20. From Figure I28, the neutral plane that was obtained from the soil settlement-pile settlement curves was at a depth of 119.0ft. The amount of settlement of the neutral plane (downdrag) for Event 1 was 2.238in.

Step 11: Perform limit state checks

Limit state checks were performed to determine if the pile size was suitable for the design loads. For the structural strength limit state, the determined drag load associated with Event 1 (215.6kips) was multiplied by the drag load factor (γDR=1.1) to obtained a factored load of drag load 237.2kips. The unfactored top load (298.5kips) placed on the top of the pile was multiplied by the deadload factor (γD=1.25) to obtained a factored deadload of 373.1. The combined total factored load was 610 kips. The yield stress for the steel pile pile was assumed to be 45ksi resulting in a factored structural stress of 40.5ksi (0.9*45ksi) and a factored structural strength of 1113kips when the stress was multiplied by the cross-sectional area of the pile wall (27.5in2). If Grade 3 A-252 pipe piles were used then the pile is adequately sized because the factored structural strength (1113kips) was determined to be greater than the combined total factored load (610kips).

Serviceability issues associated with the large ground surface movements (2.848in), large pile head movements (2.887in), and large pile toe movements (2.121in) for Event 1 (amax=0.3,Mw=6.2) are of concern. The geometry of the pile should be modified to prevent these large movements. It is suggested that the pile be lengthened to provide more positive side resistance below the depth of the neutral plane. Ground improvement techniques that will limit the amount of ground surface settlement are also recommended.

Conclusion:

The PileAXL and TZPILE programs were used in conjunction to determine the amount of drag load and downdrag resulting from a hypothetical post-liquefaction recompression in a gravel deposit at the Tok River bridge site in Alaska. The amount of soil settlement resulting from the post-liquefaction recompression was determined by using the Rollins et al. (2022), Kayen et al. (2013), and Boulanger and Idriss (2008) procedures. The calculated soil settlement profile and the obtained unit side resistance and unit end bearing values from the PileAXL program were used to identify the location of the neutral plane using the NCHRP12-116A Method A approach. The neutral plane locations obtained from the load-resistance curve and the pile-soil settlement curve in the PileAXL Method A approach were not within the required 5 foot difference. Therefore, the NCHRP12-116A Method B approach was evaluated using the TZPILE

Iteration of toe movements
Figure I28. Iteration of toe movements.
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Suggested Citation: "Appendix I: Design Example 7 - Liquefaction in Gravel Using PileAXL and TZPILE." National Academies of Sciences, Engineering, and Medicine. 2024. Pile Design for Downdrag: Examples and Supporting Materials. Washington, DC: The National Academies Press. doi: 10.17226/27864.

software program. Based on the TZPILE analysis, the 18-inch diameter by 136-foot long piles that were modeled were able to provide adequate geotechnical resistance and were structurally competent to withstand the predicted drag load. However, the amount of downdrag was excessive and longer piles and/or ground improvement techniques should be evaluated. The amounts of drag load and downdrag reported in Hemstreet (2014) and determined herein were significantly different. These differences were attributed to the differences in the amount of unfactored load that was modeled at the top of the pile and due to different pile lengths being considered.

References

Andrus, R.D., Hayati, H., and Mohanan, N.P. (2009). “Correcting Liquefaction Resistance for Aged Sands Using Measured to Estimated Velocity Ratio.” Journal of Geotechnical and Geoenvironmental Engineering, 135(6), 735-744.

Bong, T., and Stuedlein, A.W. (2018). “Effect of Cone Penetration Conditioning on Random Field Model Parameters and Impact of Spatial Variability on Liquefaction-induced Differential Settlements.” Journal of Geotechnical and Geoenvironmental Engineering, 144(5), 04018018.

Boulanger, R.W., and Idriss, I.M. (2014). “CPT and SPT based liquefaction triggering procedures.” Report No. UCD/CGM.-14, University of California, Davis, California.

Cary, J.R., Stuedlein, A.W., McGann, C.R., Bradley, B.A., and Maurer, B.W. (2022). “Effect of Refinements to CPT-Based Liquefaction Triggering Analysis on Liquefaction Severity Indices at the Avondale Playground Site, Christchurch, NZ.” Proceedings, PBDIV, Fourth Conference on Performance-based Design in Earthquake Geotechnical Engineering, Beijing, China, Springer, pp. 1454-1466.

Coduto, D.P., Kitch, W.A., and Yeung, M.R. (2016). Foundation Design :Principles and Practices, 3rd ed. Pearson Education Inc. 960 pgs.

Dadashiserej, A., Jana, A., Ortiz, S.C., Walters, J.J., Stuedlein, A.W., and Evans, T.M. (2022). “Monotonic, Cyclic, and Post-Cyclic Response of Willamette River Silt at the Van Buren Bridge.” Geotechnical Special Publication No. 334, Proceedings, Geo-Congress 2022: 431–443.ASCE.

Duku, P.M., Stewart, J.P., Whang, D.H., and Yee, E. (2008). “Volumetric Strains of Clean Sands Subject to Cyclic Loads.” Journal of Geotechnical and Geoenvironmental Engineering, 134(8), 1073–1085.

Ensoft. (2021). “TZPILE v. 2021”. Software Program.

Hemstreet, David, A. (2014). “Final Structural Foundation Engineering Report. Tok River Bridge No. 0663” August.

Hossain, A.M., Andrus, R.D., and Camp III, W.M. (2013). “Correcting liquefaction resistance of unsaturated soil using wave velocity.” Journal of Geotechnical and Geoenvironmental Engineering, 139(2), 277-287.

Idriss, I.M., and Boulanger, R.W. (2008). “Soil liquefaction during earthquakes.” Monograph MNO-12, Earthquake Engineering Research Institute, Oakland, CA, 261 pp.

Innovative Geotechnics Pty Ltd. (2023). “PileAXL 2.4: A Program for Single Piles Under Axial Loading.” Software Program.

Ishihara, K., and Yoshimine, M. (1992). “Evaluation of settlements in sand deposits following liquefaction during earthquakes.” Soils and Foundations, 32(1), 173-188.

Jana, A., and Stuedlein, A.W. (2021). “Monotonic, Cyclic, and Post-Cyclic Responses of an Alluvial Plastic Silt Deposit.” Journal of Geotechnical and Geoenvironmental Engineering 147 (3): 04020174.

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Suggested Citation: "Appendix I: Design Example 7 - Liquefaction in Gravel Using PileAXL and TZPILE." National Academies of Sciences, Engineering, and Medicine. 2024. Pile Design for Downdrag: Examples and Supporting Materials. Washington, DC: The National Academies Press. doi: 10.17226/27864.

Lee, K.L., and Albaisa, A. (1974). “Earthquake induced settlements in saturated sands.” Journal of the Geotechnical Engineering Division, 100(4), 387-406.

Robertson, P.K., and Cabal, K.L. (2015). Guide to Cone Penetration Testing for Geotechnical Engineering, 6th ed. Gregg Drilling & Testing, Inc.

Seed, H.B., and Idriss, I.M. (1971). “Simplified procedure for evaluating soil liquefaction potential.” Journal of the Soil Mechanics and Foundations Division, 97(9), 1249-1273.

Stewart, J.P., Smith, P.M., and Whang, D.H. (2002). “Documentation and analysis of field case histories of seismic compression during the 1994 Northridge, California earthquake.” Report No. PEER 2002/09, Pacific Earthquake Engineering Research Center, University of California, Berkeley, California, 246 pp.

Stuedlein, A.W., Dadashiserej, A., Jana, A., and Evans, T.M. (2023). “Liquefaction Susceptibility and Cyclic Response of Intact Nonplastic and Plastic Silts.” Journal of Geotechnical and Geoenvironmental Engineering 149 (1): 04022125.

Yoshimine, M., Nishizaki, H., Amano, K., and Hosono, Y. (2006). “Flow Deformation of Liquefied Sand Under Constant Shear Load and Its Application to Analysis of Flow Slide of Infinite Slope.” Soil Dynamics and Earthquake Engineering 26 (2-4): 253–264.

Zhang, G., Robertson, P.K., and Brachman, R.W. (2002). “Estimating Liquefaction-Induced Ground Settlements from CPT for Level Ground.” Canadian Geotechnical Journal 39 (5): 1168–1180.

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Suggested Citation: "Appendix I: Design Example 7 - Liquefaction in Gravel Using PileAXL and TZPILE." National Academies of Sciences, Engineering, and Medicine. 2024. Pile Design for Downdrag: Examples and Supporting Materials. Washington, DC: The National Academies Press. doi: 10.17226/27864.
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Suggested Citation: "Appendix I: Design Example 7 - Liquefaction in Gravel Using PileAXL and TZPILE." National Academies of Sciences, Engineering, and Medicine. 2024. Pile Design for Downdrag: Examples and Supporting Materials. Washington, DC: The National Academies Press. doi: 10.17226/27864.
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Suggested Citation: "Appendix I: Design Example 7 - Liquefaction in Gravel Using PileAXL and TZPILE." National Academies of Sciences, Engineering, and Medicine. 2024. Pile Design for Downdrag: Examples and Supporting Materials. Washington, DC: The National Academies Press. doi: 10.17226/27864.
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Suggested Citation: "Appendix I: Design Example 7 - Liquefaction in Gravel Using PileAXL and TZPILE." National Academies of Sciences, Engineering, and Medicine. 2024. Pile Design for Downdrag: Examples and Supporting Materials. Washington, DC: The National Academies Press. doi: 10.17226/27864.
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Suggested Citation: "Appendix I: Design Example 7 - Liquefaction in Gravel Using PileAXL and TZPILE." National Academies of Sciences, Engineering, and Medicine. 2024. Pile Design for Downdrag: Examples and Supporting Materials. Washington, DC: The National Academies Press. doi: 10.17226/27864.
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Suggested Citation: "Appendix I: Design Example 7 - Liquefaction in Gravel Using PileAXL and TZPILE." National Academies of Sciences, Engineering, and Medicine. 2024. Pile Design for Downdrag: Examples and Supporting Materials. Washington, DC: The National Academies Press. doi: 10.17226/27864.
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Suggested Citation: "Appendix I: Design Example 7 - Liquefaction in Gravel Using PileAXL and TZPILE." National Academies of Sciences, Engineering, and Medicine. 2024. Pile Design for Downdrag: Examples and Supporting Materials. Washington, DC: The National Academies Press. doi: 10.17226/27864.
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Suggested Citation: "Appendix I: Design Example 7 - Liquefaction in Gravel Using PileAXL and TZPILE." National Academies of Sciences, Engineering, and Medicine. 2024. Pile Design for Downdrag: Examples and Supporting Materials. Washington, DC: The National Academies Press. doi: 10.17226/27864.
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Suggested Citation: "Appendix I: Design Example 7 - Liquefaction in Gravel Using PileAXL and TZPILE." National Academies of Sciences, Engineering, and Medicine. 2024. Pile Design for Downdrag: Examples and Supporting Materials. Washington, DC: The National Academies Press. doi: 10.17226/27864.
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Suggested Citation: "Appendix I: Design Example 7 - Liquefaction in Gravel Using PileAXL and TZPILE." National Academies of Sciences, Engineering, and Medicine. 2024. Pile Design for Downdrag: Examples and Supporting Materials. Washington, DC: The National Academies Press. doi: 10.17226/27864.
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Suggested Citation: "Appendix I: Design Example 7 - Liquefaction in Gravel Using PileAXL and TZPILE." National Academies of Sciences, Engineering, and Medicine. 2024. Pile Design for Downdrag: Examples and Supporting Materials. Washington, DC: The National Academies Press. doi: 10.17226/27864.
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Suggested Citation: "Appendix I: Design Example 7 - Liquefaction in Gravel Using PileAXL and TZPILE." National Academies of Sciences, Engineering, and Medicine. 2024. Pile Design for Downdrag: Examples and Supporting Materials. Washington, DC: The National Academies Press. doi: 10.17226/27864.
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Suggested Citation: "Appendix I: Design Example 7 - Liquefaction in Gravel Using PileAXL and TZPILE." National Academies of Sciences, Engineering, and Medicine. 2024. Pile Design for Downdrag: Examples and Supporting Materials. Washington, DC: The National Academies Press. doi: 10.17226/27864.
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Suggested Citation: "Appendix I: Design Example 7 - Liquefaction in Gravel Using PileAXL and TZPILE." National Academies of Sciences, Engineering, and Medicine. 2024. Pile Design for Downdrag: Examples and Supporting Materials. Washington, DC: The National Academies Press. doi: 10.17226/27864.
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Suggested Citation: "Appendix I: Design Example 7 - Liquefaction in Gravel Using PileAXL and TZPILE." National Academies of Sciences, Engineering, and Medicine. 2024. Pile Design for Downdrag: Examples and Supporting Materials. Washington, DC: The National Academies Press. doi: 10.17226/27864.
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Suggested Citation: "Appendix I: Design Example 7 - Liquefaction in Gravel Using PileAXL and TZPILE." National Academies of Sciences, Engineering, and Medicine. 2024. Pile Design for Downdrag: Examples and Supporting Materials. Washington, DC: The National Academies Press. doi: 10.17226/27864.
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Suggested Citation: "Appendix I: Design Example 7 - Liquefaction in Gravel Using PileAXL and TZPILE." National Academies of Sciences, Engineering, and Medicine. 2024. Pile Design for Downdrag: Examples and Supporting Materials. Washington, DC: The National Academies Press. doi: 10.17226/27864.
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Suggested Citation: "Appendix I: Design Example 7 - Liquefaction in Gravel Using PileAXL and TZPILE." National Academies of Sciences, Engineering, and Medicine. 2024. Pile Design for Downdrag: Examples and Supporting Materials. Washington, DC: The National Academies Press. doi: 10.17226/27864.
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Suggested Citation: "Appendix I: Design Example 7 - Liquefaction in Gravel Using PileAXL and TZPILE." National Academies of Sciences, Engineering, and Medicine. 2024. Pile Design for Downdrag: Examples and Supporting Materials. Washington, DC: The National Academies Press. doi: 10.17226/27864.
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Suggested Citation: "Appendix I: Design Example 7 - Liquefaction in Gravel Using PileAXL and TZPILE." National Academies of Sciences, Engineering, and Medicine. 2024. Pile Design for Downdrag: Examples and Supporting Materials. Washington, DC: The National Academies Press. doi: 10.17226/27864.
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Suggested Citation: "Appendix I: Design Example 7 - Liquefaction in Gravel Using PileAXL and TZPILE." National Academies of Sciences, Engineering, and Medicine. 2024. Pile Design for Downdrag: Examples and Supporting Materials. Washington, DC: The National Academies Press. doi: 10.17226/27864.
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Suggested Citation: "Appendix I: Design Example 7 - Liquefaction in Gravel Using PileAXL and TZPILE." National Academies of Sciences, Engineering, and Medicine. 2024. Pile Design for Downdrag: Examples and Supporting Materials. Washington, DC: The National Academies Press. doi: 10.17226/27864.
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Suggested Citation: "Appendix I: Design Example 7 - Liquefaction in Gravel Using PileAXL and TZPILE." National Academies of Sciences, Engineering, and Medicine. 2024. Pile Design for Downdrag: Examples and Supporting Materials. Washington, DC: The National Academies Press. doi: 10.17226/27864.
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Suggested Citation: "Appendix I: Design Example 7 - Liquefaction in Gravel Using PileAXL and TZPILE." National Academies of Sciences, Engineering, and Medicine. 2024. Pile Design for Downdrag: Examples and Supporting Materials. Washington, DC: The National Academies Press. doi: 10.17226/27864.
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Suggested Citation: "Appendix I: Design Example 7 - Liquefaction in Gravel Using PileAXL and TZPILE." National Academies of Sciences, Engineering, and Medicine. 2024. Pile Design for Downdrag: Examples and Supporting Materials. Washington, DC: The National Academies Press. doi: 10.17226/27864.
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Suggested Citation: "Appendix I: Design Example 7 - Liquefaction in Gravel Using PileAXL and TZPILE." National Academies of Sciences, Engineering, and Medicine. 2024. Pile Design for Downdrag: Examples and Supporting Materials. Washington, DC: The National Academies Press. doi: 10.17226/27864.
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Suggested Citation: "Appendix I: Design Example 7 - Liquefaction in Gravel Using PileAXL and TZPILE." National Academies of Sciences, Engineering, and Medicine. 2024. Pile Design for Downdrag: Examples and Supporting Materials. Washington, DC: The National Academies Press. doi: 10.17226/27864.
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Suggested Citation: "Appendix I: Design Example 7 - Liquefaction in Gravel Using PileAXL and TZPILE." National Academies of Sciences, Engineering, and Medicine. 2024. Pile Design for Downdrag: Examples and Supporting Materials. Washington, DC: The National Academies Press. doi: 10.17226/27864.
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Suggested Citation: "Appendix I: Design Example 7 - Liquefaction in Gravel Using PileAXL and TZPILE." National Academies of Sciences, Engineering, and Medicine. 2024. Pile Design for Downdrag: Examples and Supporting Materials. Washington, DC: The National Academies Press. doi: 10.17226/27864.
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Suggested Citation: "Appendix I: Design Example 7 - Liquefaction in Gravel Using PileAXL and TZPILE." National Academies of Sciences, Engineering, and Medicine. 2024. Pile Design for Downdrag: Examples and Supporting Materials. Washington, DC: The National Academies Press. doi: 10.17226/27864.
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Suggested Citation: "Appendix I: Design Example 7 - Liquefaction in Gravel Using PileAXL and TZPILE." National Academies of Sciences, Engineering, and Medicine. 2024. Pile Design for Downdrag: Examples and Supporting Materials. Washington, DC: The National Academies Press. doi: 10.17226/27864.
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Suggested Citation: "Appendix I: Design Example 7 - Liquefaction in Gravel Using PileAXL and TZPILE." National Academies of Sciences, Engineering, and Medicine. 2024. Pile Design for Downdrag: Examples and Supporting Materials. Washington, DC: The National Academies Press. doi: 10.17226/27864.
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Suggested Citation: "Appendix I: Design Example 7 - Liquefaction in Gravel Using PileAXL and TZPILE." National Academies of Sciences, Engineering, and Medicine. 2024. Pile Design for Downdrag: Examples and Supporting Materials. Washington, DC: The National Academies Press. doi: 10.17226/27864.
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Suggested Citation: "Appendix I: Design Example 7 - Liquefaction in Gravel Using PileAXL and TZPILE." National Academies of Sciences, Engineering, and Medicine. 2024. Pile Design for Downdrag: Examples and Supporting Materials. Washington, DC: The National Academies Press. doi: 10.17226/27864.
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Suggested Citation: "Appendix I: Design Example 7 - Liquefaction in Gravel Using PileAXL and TZPILE." National Academies of Sciences, Engineering, and Medicine. 2024. Pile Design for Downdrag: Examples and Supporting Materials. Washington, DC: The National Academies Press. doi: 10.17226/27864.
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Suggested Citation: "Appendix I: Design Example 7 - Liquefaction in Gravel Using PileAXL and TZPILE." National Academies of Sciences, Engineering, and Medicine. 2024. Pile Design for Downdrag: Examples and Supporting Materials. Washington, DC: The National Academies Press. doi: 10.17226/27864.
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Suggested Citation: "Appendix I: Design Example 7 - Liquefaction in Gravel Using PileAXL and TZPILE." National Academies of Sciences, Engineering, and Medicine. 2024. Pile Design for Downdrag: Examples and Supporting Materials. Washington, DC: The National Academies Press. doi: 10.17226/27864.
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Suggested Citation: "Appendix I: Design Example 7 - Liquefaction in Gravel Using PileAXL and TZPILE." National Academies of Sciences, Engineering, and Medicine. 2024. Pile Design for Downdrag: Examples and Supporting Materials. Washington, DC: The National Academies Press. doi: 10.17226/27864.
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Suggested Citation: "Appendix I: Design Example 7 - Liquefaction in Gravel Using PileAXL and TZPILE." National Academies of Sciences, Engineering, and Medicine. 2024. Pile Design for Downdrag: Examples and Supporting Materials. Washington, DC: The National Academies Press. doi: 10.17226/27864.
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Suggested Citation: "Appendix I: Design Example 7 - Liquefaction in Gravel Using PileAXL and TZPILE." National Academies of Sciences, Engineering, and Medicine. 2024. Pile Design for Downdrag: Examples and Supporting Materials. Washington, DC: The National Academies Press. doi: 10.17226/27864.
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Suggested Citation: "Appendix I: Design Example 7 - Liquefaction in Gravel Using PileAXL and TZPILE." National Academies of Sciences, Engineering, and Medicine. 2024. Pile Design for Downdrag: Examples and Supporting Materials. Washington, DC: The National Academies Press. doi: 10.17226/27864.
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Suggested Citation: "Appendix I: Design Example 7 - Liquefaction in Gravel Using PileAXL and TZPILE." National Academies of Sciences, Engineering, and Medicine. 2024. Pile Design for Downdrag: Examples and Supporting Materials. Washington, DC: The National Academies Press. doi: 10.17226/27864.
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Suggested Citation: "Appendix I: Design Example 7 - Liquefaction in Gravel Using PileAXL and TZPILE." National Academies of Sciences, Engineering, and Medicine. 2024. Pile Design for Downdrag: Examples and Supporting Materials. Washington, DC: The National Academies Press. doi: 10.17226/27864.
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Suggested Citation: "Appendix I: Design Example 7 - Liquefaction in Gravel Using PileAXL and TZPILE." National Academies of Sciences, Engineering, and Medicine. 2024. Pile Design for Downdrag: Examples and Supporting Materials. Washington, DC: The National Academies Press. doi: 10.17226/27864.
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Suggested Citation: "Appendix I: Design Example 7 - Liquefaction in Gravel Using PileAXL and TZPILE." National Academies of Sciences, Engineering, and Medicine. 2024. Pile Design for Downdrag: Examples and Supporting Materials. Washington, DC: The National Academies Press. doi: 10.17226/27864.
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Suggested Citation: "Appendix I: Design Example 7 - Liquefaction in Gravel Using PileAXL and TZPILE." National Academies of Sciences, Engineering, and Medicine. 2024. Pile Design for Downdrag: Examples and Supporting Materials. Washington, DC: The National Academies Press. doi: 10.17226/27864.
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Suggested Citation: "Appendix I: Design Example 7 - Liquefaction in Gravel Using PileAXL and TZPILE." National Academies of Sciences, Engineering, and Medicine. 2024. Pile Design for Downdrag: Examples and Supporting Materials. Washington, DC: The National Academies Press. doi: 10.17226/27864.
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Next Chapter: Appendix J: Design Example 8 - Embankment Over Clay Over Rock Using PileAXL
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