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:
t Water is added to an open-ended pipe casing sunk to desired depth. With constant head tests, constant rate of gravity flow into hole and casing pipe are measured. Variations include applied pressure tests and falling head tests. Rough approximation of in situ permeability of soils and rock mass. Pipe casing must be carefully cleaned out just to the bottom of the casing. Clear water must be used or tests may be grossly misleading. Measurement of local permeability only. Direct shear test Block of in situ rock is isolated to permit shearing along a preselected surface. Normal and shearing loads are applied by jacking. Loads and displacements are recorded. Measurement of shearing resistance of rock mass in situ. Tests are costly. Usually, variability of rock mass requires a sufficient number of tests to provide statistical control. Pressure tunnel test Hydraulic pressure is applied to sealed-off length of circular tunnel, and diametral deformations are measured. Determination of elastic constants of the rock mass in situ. Volume of rock tested is dependent on tunnel diameter. Cracking caused by tensile hoop stresses may affect apparent stiffness of rock. Radial jacking test Radial pressure is applied to a length of circular tunnel by flat jacks. Diametral deformations are measured. Same as pressure tunnel test. Same as pressure tunnel test. Borehole jack test Load is applied to wall of borehole by two diametrically opposed jacks. Deformations and pressures are recorded. Determination of elastic modulus of rock in situ. Capable of applying greater pressure than dilatometers. Apparent stiffness may be affected by development of tension cracks. Borehole deformation meter Device for measuring diameters is placed in borehole, and hole is overcored to relieve stresses on annular rock core with deformation meter. Diameters (usually 3) are measured before and after overcoring. Rock modulus is measured by laboratory tests on core; in situ stresses are computed by elastic