There are a lot of cross fissures in natural rock mass,which seriously affect the deformation,failure and instability law of rock mass structures.Sandstone material is made of rock samples with different main and secondary crack dip angles as the research object.By using uniaxial compression and digital image processing(DIC)imaging test methods,the influence of cross crack occurrence on the mechanical properties and failure mode of rock samples was studied.The results show that compared with the single crack,the peak strength and elastic modulus of the rock sample with single crack are generally greater than those of the rock sample with cross cracks,indicating that cross cracks will further weaken the mechanical properties of the rock sample.When α ≤45°,α=60° andβ≤45°,the initiation of the secondary crack tip crack is basically earlier than that of the primary crack,the secondary crack tip crack does not propagate through,and the primary crack tip crack is connected.When α=60°,β≥60° and α=90°,the crack initiation at the tip of the primary crack is basically earlier than that at the secondary crack,and the secondary crack extends through,while the primary crack does not.The cracks mainly spread along the direction of up and down,and the horizontal cracks are less.Among them,α is the main fracture and horizontal inclination,β is the secondary fracture and main fracture inclination.When α is 0° and 90°,all rock samples exhibit tensile failure.When α is 30°,45° and 60°,rock samples exhibit a change from shear failure to tension-shear composite failure to tension-tensile failure with the increase of β.The main failure crack is controlled by a longer horizontal projection of the main crack and the secondary crack.
万方数据
维普
