Document: NRC Regulatory Guide
Document ID: 1859c547-c10c-4ce4-ad2e-e54f7b66d4ef
Document Type: regulatory_guide
Title: Laboratory Investigations of Soils and Rocks for Engineering Analysis and Design of Nuclear Power Plants + HISTORY – HISTORY 07/2014 – DG-1256 , Proposed Revision 3 08/2001 – DG-1109 , Proposed Revision 2 (Rev. 3)
Source: NRC Regulatory Guide Division 1
Source URL: https://www.nrc.gov/docs/ML1318/ML13186A032.pdf
Revision Date: 2023-06
Chapter: 
Section ID: RG-1.138
CFR Part: 
CFR Title: 

Content:
or extruding samples. Undisturbed tube samples should satisfy the following criteria: (1) The specific recovery ratio should be between 90 and 100 percent; a tube with less recovery may be acceptable if it appears that the sample was broken off, but appears otherwise undisturbed. Investigators should record and document the actual recovery obtained. (2) The surface or sliced sections of the sample should have no visible distortions, planes of failure, pitting, discoloration, or other signs of disturbance that can be attributed to the sampling operation or handling of the sample. (3) The net length and weight of the sample and the results of other control tests should not have changed during shipment, storage, and handling of the sample. c. In addition to the above, samples that have been subjected to violent mechanical shocks or to accidental freezing and thawing should not be considered undisturbed, even if other evidence of disturbance is absent. d. To permit establishment of the soil and geologic profiles, investigators should ensure that test specimens are representative of each discrete soil or rock unit to be tested and are accurately described on the basis of classification tests. Physical and engineering property tests of in situ soils, whether cohesive or cohesionless, should use the highest quality and most representative undisturbed samples available. e. Trimming and shaping of test specimens of soils require great care to prevent disturbance and changes in water content. Frozen samples should be prepared under conditions that will prevent premature thawing. f. Laboratory personnel should record a complete detailed description of the specimen that includes, but is not limited to, the material, color, consistency, and brittleness of the material and any indication that the boring samples were disturbed. Personnel should not use disturbed samples for any test other than classification and tests that do not require an undisturbed sample. When a sample is