TY - JOUR
T1 - Linking stress-dependent effective porosity and hydraulic conductivity fields to RMR
AU - Liu, J.
AU - Elsworth, D.
AU - Brady, B. H.
N1 - Funding Information:
The work reported in this paper was supported by the National Science Foundation under Grant No. MSS-9209059 and by the Australian Research Council under Large Grant No. A89600730. The sources of this support are gratefully acknowledged. The authors also thank two anonymous reviewers for providing critical comments and constructive suggestions in revising the manuscript.
PY - 1999
Y1 - 1999
N2 - Relations are developed to define changes in effective porosity and hydraulic conductivity that result from the redistribution of stresses and strains in disturbed rock masses. In each instance, changes in porosity and directional conductivities are determined from pre-disturbance porosities and conductivities, knowledge of the number of joint sets, and the indices of Rock Quality Designation (RQD) and Rock Mass Rating (RMR), defining the rock mass structure. Measured magnitudes, or estimates, of the applied strain distribution are the final required parameter. These parameters allow porosity and conductivity changes to be straightforwardly evaluated for a broad spectrum of rock mass qualities, including the representation of granular media. The model is applied to an effective stress analysis of conductivity changes that develop around a unlined circular drift in a biaxial stress field. Large increases in tangential conductivity, and reductions in radial conductivity are shown to result. These results are corroborated against the drift macropermeability test at Stripa where increases in hydraulic conductivity of the order of 1000-10000 times were measured in a 0.5-1.0 m wide zone adjacent to the excavation.
AB - Relations are developed to define changes in effective porosity and hydraulic conductivity that result from the redistribution of stresses and strains in disturbed rock masses. In each instance, changes in porosity and directional conductivities are determined from pre-disturbance porosities and conductivities, knowledge of the number of joint sets, and the indices of Rock Quality Designation (RQD) and Rock Mass Rating (RMR), defining the rock mass structure. Measured magnitudes, or estimates, of the applied strain distribution are the final required parameter. These parameters allow porosity and conductivity changes to be straightforwardly evaluated for a broad spectrum of rock mass qualities, including the representation of granular media. The model is applied to an effective stress analysis of conductivity changes that develop around a unlined circular drift in a biaxial stress field. Large increases in tangential conductivity, and reductions in radial conductivity are shown to result. These results are corroborated against the drift macropermeability test at Stripa where increases in hydraulic conductivity of the order of 1000-10000 times were measured in a 0.5-1.0 m wide zone adjacent to the excavation.
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U2 - 10.1016/S0148-9062(99)00029-7
DO - 10.1016/S0148-9062(99)00029-7
M3 - Article
AN - SCOPUS:0032848925
SN - 0148-9062
VL - 36
SP - 581
EP - 596
JO - International Journal of Rock Mechanics and Mining Sciences
JF - International Journal of Rock Mechanics and Mining Sciences
IS - 5
ER -