Shearing Of Rock Joints With Different Roughness Theoretical Analysis Of Cutting Test

Through the systematic artificial joint surface with different roughness(model material joint surface),the test piece with different undulation angles is made of the same material for direct shear test,and its physical and mechanical parameters are obtained,and the peak strength and residual strength values are studied.The correlation between the undulation angle and the deformation characteristics of the joint plane,the tangential stress-tangential displacement relationship diagram,the residual strength and the normal stress curve characteristics,the obtained residual strength criterion and the existing strength criterion are fitted,and the empirical formula is used.Compared with the actual test results,the revised strength criterion is deduced and applied to the rock slope actual engineering to solve the slope protection and other issues.The main research contents are as follows:(1)Summarize the failure mode of rock joint surface,analyze the tangential stress-tangential displacement relationship diagram,displacement difference-cycle shear number histogram,deductive cohesion c,internal friction angle and residual in the strength weakening stage The relationship between the intensity and the existing empirical formula is fitted,and the residual intensity satisfies the Coulomb-Mohr criterion.(2)In the later stage of the experiment,the tangential stress is applied by cyclic loading and unloading,so that the undulation angle is subject to wear and the angle becomes smaller.Therefore,the residual strength will be greatly reduced first,then slowly decreased,and finally reach a steady state,the number of shearing increases,and the residual of the joint surface The closer the shear strength is,the more it will be fixed.In order to obtain a more accurate residual strength change,compared with the existing Mohr-Coulomb criterion and Hoek-Brown criterion,the theoretical relationship is analyzed,and the residual strength is more suitable for the Hoek-Brown criterion.Comparing the experimental data,the Hoek-Brown criterion has a smaller error range of intensity and data values,less than 20%.(3)Perform the force decomposition of the regular sawtooth oblique section,and combine the Hoek-Brown criterion to correct the proposed empirical formula to obtain a modified formula that meets the experimental conclusion.