Shear crack propagation laws and fracture mechanism of filled joint granite with different angles
In enhanced geothermal systems(EGS)reservoirs,rock fractures in the form of filled joints often contain fillings,and the shear mechanical behavior of filled joints directly affects the permeability and connectivity of the reservoir.Based on direct shear tests on filled joint granite with different angles,this study investigates the mechanical characteristics of shear failure,evolution of damage variables,and crack propagation laws of granite with filled joints.The results indicate that the filling material and joint angle affect the shear strength of granite.The filling material alters the medium for crack propagation while the joint angle affects the stress state of the joint surface during shear.The process of damage and failure in granite with filled joints can be divided into three stages:crack closure,crack initiation and development,and crack propagation and failure.The damage variable increases continuously as the stages progress.The direction of shear crack propagation in jointed granite can be classified into horizontal direction and parallel-to-the joint direction.For specimens with joints at 0° and 90°,the shear crack extends horizontally until it penetrates the specimen.For specimens with joints at 30°,45°,and 60°,the direction of shear crack propagation aligns with the joint angle.
rock mechanicsfilled jointjoint anglefracture mechanismdamage evolution
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