Document: NRC Regulatory Guide
Document ID: a094549d-8685-4dad-b90f-c28c7d279a53
Document Type: regulatory_guide
Title: Geologic and Geotechnical Site Characterization Investigations for Nuclear Power Plants + HISTORY – HISTORY 08/2021 – DG-1392 , Proposed Revision 3 07/2014 – Periodic Review of Revision 2 – Reviewed with no issues identified 02/2001 – DG-1101 , Proposed Revision 2 (Rev. 3)
Source: NRC Regulatory Guide Division 1
Source URL: https://www.nrc.gov/docs/ML2119/ML21194A176.pdf
Revision Date: 2023-05
Chapter: 
Section ID: RG-1.132
CFR Part: 
CFR Title: 

Content:
and compared by Nicholson (1983; Ref. 20) and Bowles (1996; Ref. 21). The suggested in situ method for determining direct shear strength of rocks is described in RTH 321-80, “Suggested Method for In Situ Determination of Direct Shear Strength (ISRM),” issued 1980 (Ref. 22). Although the standard penetration test (SPT) is used extensively in investigations of soil liquefaction susceptibility, the cone penetration test (CPT) is also widely used in site investigation because (1) the CPT provides continuous penetration resistance profiles for soils and (2) CPT results are more repeatable and consistent (Ref. 23). Both Appendix C and Appendix F compare the applicability and limitations of the CPT and SPT. 4.10 Geophysical Investigations 4.10.1 General Geophysical investigations include surface geophysical surveys and borehole logging and other testing techniques, which are important for determining subsurface engineering properties and geologic and hydrologic characteristics, features, and conditions. Data from these investigations should be used to provide more continuous, and possibly deeper, subsurface information for filling in between data derived from surface outcrops, trenches, and boreholes and correlating data from other sources. Available geophysical and borehole logging methods are listed in Appendix E to this guide and in EM-1110-1-1802, “Geophysical Exploration for Engineering and Environmental Investigations,” issued 1995 (Ref. 24). A geophysical exploration should consider the following factors: (1) Subsurface and surface geophysical investigations cannot be substituted for each other. Both surface and subsurface geophysical investigations should be conducted to validate and calibrate site investigation results. (2) For subsurface material engineering properties that could have high consequences if they are not determined properly, or are deemed critical to safe performance of the facility, multiple tests using different methods are recommended to