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:
toric lakes. Determine settlement behavior of structures in the area. Check natural slopes and cuts for varved clays; check settlement behavior of structures. DG-1392, Appendix A, Page A-5 APPENDIX A, Cont’d. GEOLOGIC FEATURE OR CONDITION INFLUENCE ON PROJECT OFFICE STUDIES FIELD OBSERVATIONS QUESTIONS TO ANSWER Dispersive clays Is a major factor in selecting soils for embankment dams and levees. Check with Soil Conservation Service and other agencies regarding behavior of existing small dams. Look for peculiar erosional features, such as vertical or horizontal cavities in slopes or unusual erosion in cut slopes. Perform “crumb” test. Riverbank and other liquefaction areas Has a major effect on riverbank stability and on foundation stability in seismic areas. Locate potential areas of loose fine-grained alluvial or terrace sand, most likely along riverbanks where loose sands are present and erosion is occurring. Check riverbanks for scallop-shaped failure with narrow neck (may be visible during low water). If present, determine shape, depth, average slope, and slope of adjacent sections. Liquefaction in wooded areas may leave trees inclined at erratic angles. Look for evidence of sand boils in seismic areas. Filled areas Relatively recent filled areas would cause large settlements. Such fill areas may be overgrown and not detected from surface or even subsurface evidence. Check old topo maps, if available, for depressions or gullies not shown on more recent topo maps. Obtain local history of site from area residents. Local overconsolidation from previous site usage Local areas of a site may have been overconsolidated from past heavy loadings of lumber or material storage piles. Obtain local history from residents of area. DG-1392, Appendix B, Page B-1 APPENDIX B SOURCES OF GEOLOGIC INFORMATION (adapted from EM 1110-1-1804, U.S. ARMY CORPS OF ENGINEERS, 2001) AGENCY TYPE OF INFORMATION DESCRIPTION REMARKS U.S. Geological Survey (USGS) Topographic maps U.S.