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:
ty, and shear strength. Therefore, selection of the correct sample container material is important. Unless stabilized chemically or by freezing, cohesionless soil samples are particularly sensitive to disturbance from impact and vibration during removal from the borehole or sampler and subsequent handling. Samples should (1) be kept in the same orientation as that in which the samples were taken at all times (e.g., in a vertical position if sampled in a vertical borehole), (2) be well padded for isolation from vibration and impact, and (3) be transported with extreme care if undisturbed samples are required. 4.9 In Situ Testing In situ testing of soil and rock materials should be conducted where necessary for definition of subsurface material properties and in situ state of stress using boreholes, excavations, test pits, and trenches that are either available or have been prepared for sampling and testing. Larger block samples for laboratory testing can also be obtained at the same locations. Appendix F to this guide shows some applicable in situ testing methods. NUREG/CR-5738 further describes the procedures. In situ tests are often the best means to determine the engineering properties of subsurface materials and, in some cases, might be the only way to obtain meaningful results. Some materials are hard to sample and transport while keeping them representative of field conditions, because of softness, lack of cohesion, or composition. In situ testing techniques offer a valuable option for evaluating soils and rocks that cannot be sampled for laboratory analysis. Interpretation of in situ test results in soils, clay-rich shales, and moisture-sensitive rocks requires consideration of the drainage that may occur during the test. Consolidation during soil testing makes it difficult to determine whether the results relate to unconsolidated-undrained, consolidated-undrained, consolidated-drained, or unconsolidated-drained conditions or to intermediate conditions between