Document: NUREG-0800
Document ID: 1c866a17-8421-43d4-bdf4-ef58029f1ecb
Document Type: srp
Title: - Liquefaction Potential.  In meeting the requirements of 10 CFR Parts
Source: NUREG-0800
Source URL: https://www.nrc.gov/docs/ML1230/ML12302A004.pdf
Revision Date: 2023-06
Chapter: 2
Section ID: 2.5.4.8
CFR Part: 
CFR Title: 

Content:
and 100, if the foundation materials at the site adjacent to and under Category I structures and facilities are saturated soils and the water table is above bedrock, then an analysis of the liquefaction potential at the site is required. The need for a detailed analysis is determined by a study on a case-by-case basis of the site stratigraphy, critical soil parameters, and the location of safety-related foundations. Undisturbed samples obtained at the site and appropriate laboratory tests are required to show if the soils are likely to liquefy. Liquefaction potential assessments using both deterministic and probabilistic approaches are desirable. When the need for an in-depth analysis is indicated, it may be based on cyclic triaxial test or other state-of-the-art test data obtained from undisturbed soil samples taken from the critical zones at the site. The seismic force used to determine shear stresses induced in the soil should be consistent with the ground motion determined in a manner that is consistent with SRP Section 2.5.2. The site specific GMRS (adjusted to the depth of liquefiable layer) that meets the requirements of Appendix S, 10 CFR Part 50 with respect to the peak ground acceleration, should be used to evaluate the potential for liquefaction. The criterion that should be used to determine when the soil samples tested "liquefied" should be taken as the onset of liquefaction (defined as the cycle when the pore pressure first equals the confining pressure). Test data showing the rate of pore pressure increase with number of cycles should be presented. If the behavior of the pore pressure is such that peak to peak axial strains greater than a few percent occur before liquefaction, then the applicant must include the effects of these strains in his assessment of the potential hazards that complete or partial liquefaction could have on the stability and settlement of any Category I structures. 2.5.4-14 Draft Revision 5 – August 2013 Non-seismic