The research investigation is conducted to perform an analysis of sensitivity of parameters affecting the strength of joints in rock mass. Friction angle, normal stiffness, shear stiffness and shear displacement are the parameters analyzed with respect to shear strength of rock joints. Discontinuities have an important influence on the deformational behavior of rock systems; hence, proper consideration of the physical and mechanical properties of discontinuities is necessary during experimental investigation, in order to correctly evaluate the shear behavior. These parameters are utilized to simulate the in situ stress condition in numerical modeling, which is important for safe and economical design of various engineering constructions. These concerns require accurate quantification of shear strength of unfilled and in-filled joints, proper understanding of the basic mechanics of discontinuity and the principals involved in their shear deformation. This can be achieved through laboratory testing on natural rock core samples. In the present work, the detailed account of test results of direct shear tests performed on rock joints is presented. Rock samples are obtained by core drilling in an underground mine, in Nevada. These rock samples, containing joint, are used to perform direct shear strength test. Calibration of numerical model is done on average values obtained from direct shear strength test. Analysis of sensitivity of parameters effecting shear strength of rock is done in FLAC3D shear test environment. A numerical parametric study is done, according to the Mohr-Coulomb constitutive model, and results obtained are plotted to estimate performance of rock joints.
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