Test and estimation on the shear parameters of structural plane from Jincheng anthracite coal

In order to study the shear strength and related parameters of coal structural planes from Jincheng an-thra- cite coal,some direct shear tests under different normal stresses were carried out on coal samples with structural planes from No,3 coal seam of Sihe mine,and also the three dimensional photogrammetry of the structural surface topography was carried out. The tests obtained some experimental values and estimated values. The test results show that under a low normal stress level,the stiffness range of coal structural plane is 13-39． 2 GPa / cm,and the range of shear stiffness is 3． 1-26． 6 GPa / cm. Under a moderate normal stress level,the stiffness range of coal structural plane is 13. 8-62． 0 GPa / cm,and the range of shear stiffness is 4． 3-18． 2 GPa / cm,The average cohesion of coal structural plane is 0． 67 MPa,and the average peak friction angle is 37 degree. With the increase of normal stress,the normal stiffness, shear stiffness and shear strength of the structural plane also increase. The test values provide a reference for the pa- rameters in numerical simulation. Through the comparison between calculated shear strength and experimental shear strength,the JRC-JCS model can be used to predict the shear strength of the structural plane.