TRB's National Cooperative Highway Research Program (NCHRP) Web-Only Document 258: Manual on Subsurface Investigations provides an update to the American Association of State Highway Transportation Officials (AASHTO) 1988 manual of the same name. This report reflects the changes in the approaches and methods used for geotechnical site characterization that the geotechnical community has developed and adopted in the past thirty years. The updated manual provides information and guidelines for planning and executing a geotechnical site investigation program. It may also be used to develop a ground model for planning, design, construction, and asset management phases of a project.
Sign in to access your saved publications, downloads, and email
preferences.
Former MyNAP users: You'll need to reset your password on your first
login to MyAcademies. Click "Forgot password" below to receive a reset
link via email. Having trouble?
Visit our FAQ page
to contact support.
Members of the National Academy of Sciences, National Academy of
Engineering, or National Academy of Medicine should log in through their
respective Academy portals.
Register
Register
Thank You
Thank You
Thank you for creating a MyAcademies account!
Enjoy free access to thousands of National Academies' publications, a
10% discount off every purchase, and build your personal library.
Forgot Password
Forgot Password
Enter the email address for your MyAcademies (formerly MyNAP) account to
receive password reset instructions.
Reset Requested
Reset Requested
We sent password reset instructions to
your email
. Follow the link in that email to create a new password. Didn't receive
it? Check your spam folder or
contact us
for assistance.
We sent a verification link to your email. Please check your inbox (and
spam folder) and follow the link to verify your email address. If you
did not receive the email, you can request a new verification link below