EXPERIMENTAL STUDY ON PEAK SHEAR STRENGTH CRITERION FOR ROCK JOINTS
YANG Jie1，2，RONG Guan1，2，CHENG Long1，2，HOU Di1，2，WANG Xiaojiang3
(1. State Key Laboratory of Water Resources and Hydropower Engineering Science，Wuhan University，Wuhan，Hubei 430072
2. Key Laboratory of Rock Mechanics in Hydraulic Structural Engineering，Ministry of Education，Wuhan，Hubei 430072
3. Mid-south Design and Research Institute，China Hydropower Engineering Consulting Group Co.，Changsha，Hunan 410014)
Abstract：The three-dimensional morphology of a rock joint have a great impact on its shear behavior. In order to study ofrelationship between the three-dimensional morphology characteristics and peak shear strength of rock joints，fresh tensile rock joints of granite and sandstone are prepared anddirect shear tests are carried out under different constant norm loads. The morphology of each jointwas measured before the direct shear tests.The three-dimensional morphological parameters of each joint were calculated. Then，by analyzing the test results，a new peak shear strength criterion of rock joints is proposed using twothree-dimensional morphological parameters which are termed as the maximum apparent dip angle and a roughness parameter C. Direct shear test data of tensile rock joints collected from Grasselli are used to further verify the proposed criterion. A comparison among the new criterion，Grasselli’s criterion and Xia?s criterion are made from the perspective of both the rationality of the formula and the prediction accuracy for the 50 groups of joints. It turn out that the new criterion have some advantages in predicting peak shear strength of rock joints.
2015, Vol. 34 
