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:
ned based on the type and number of tests planned. A sufficient quantity of each fill type should be collected, preferably all during the initial sampling efforts, to ensure better uniformity in soils collected and sampling methods. 4.7 Materials Unsuitable for Foundations Boundaries of unsuitable materials should be delineated by borings and representative sampling and testing. These boundaries should be used to define the required excavation limits. 4.8 Transportation and Storage of Samples Handling, storage, and transportation of samples are as critical for sample quality as the collection procedures used. Disturbance of samples after collection can happen in a variety of ways and transform samples from high quality to slightly disturbed to unusable. Soil samples can change dramatically because of moisture loss, moisture migration within the sample, freezing, vibration, shock, or chemical reactions. Moisture loss might not be critical on representative samples but should be kept to a minimum. Moisture migration within a sample can cause differential residual pore pressure to equalize with time. Water can move from one layer to another, causing significant changes in the undrained strength and compressibility of the sample. Freezing of clay or silt samples can cause ice lenses to form and severely disturb the samples. Therefore, storage room temperatures for clay and silt samples should be kept above 4 degrees Celsius (C). Vibration or shock can provoke remolding and strength or density changes, especially in soft and sensitive clays, and cohesionless samples. Transportation should be carefully arranged to avoid such effects. Chemical reactions between samples and sample containers can occur during storage and induce changes that affect soil plasticity, compressibility, 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