The Experimental Research And Numerical Simulation On The Formation Of Shear Band Of Rock

The paper studies the deformation process and formation of shear zone of the red mud-sand stone and mud stone in Chongqing region under uniaxial compression with the laser-speckle double-interference technique, and the RFPA software is used to numerically simulate the process of rock deformation localization.Experiment results show that the deformation localization behavior appears in the most of all tested samples, and the deformation localization properties of rock under uniaxial compression.The test results show that the first stage of deformation, i.e. elastic, develops steadily, then followed by an unstable one, and that when the loading reaches 60% the peak strength of the test coupon, a stable localization zone of distortion ensues; and when the loading is equal to or over the peak strength, visible cracks appear and macro failure results. The analysis and comparison of change in the dip angle of the shear zone, in combination with speckle graphs of the red mud-sand stone and sand stone, show the change of the mud-sand rock in the dip angle of deformation shear zone is greater than that of sand rock and the dip angle of the mud-sand rock tends to a fixed direction finally, while the direction of deformation localization shear zone of sand stone is comparatively fixed and forms a conjugate shear zone.Based on the grads plastic theory, the grads plastic relationship is set up, which can be used to describe rock's deformation and failure, and from which the relationship between the width of the shear zone and the internal length derives with the internal length of the rock sample being determined.The RFPA software is used to numerically simulate the process of deformation and failure of tested samples and the comparison and analysis of their deformation, failure processes and forms of localization shear zone with varying confining pressures being applied to, are made.