Abstract：Shear strength of structural plane has an important influence on stability of engineering rock mass. It determines the probability of engineering rock mass failure. JRC-JCS model based on directional statistical measurement technology of roughness coefficient of structural plane can consider the effect of geology and environment. For structural planes with few filling or without filling，JRC-JCS model with advantages of low cost，fast estimation and easy manipulation can provide a practical method to obtain the shear strength parameters of structural plane in hard rocks. The model has been applied to fifty rock projects in order to get the shear strength parameters of structural planes. To analyze the reliability of estimating the shear strength parameters of structural planes with JRC-JCS model，the shear strengths of natural rocks with structural plane under dry and saturated conditions are measured by direct shear test and empirical estimation with JRC-JCS model. Then，the test results of shear strength are compared. The results show that the shear strength parameters estimated by JRC-JCS model and direct shear test agree well with each other on the basis of the directional statistical measurement，the analysis of JRC scale effect and the consideration of reduced JRC during the course of shear；and JRC-JCS model can estimate the peak friction angle of structural plane well.
