Study On The Weakening Effect Of Mechanical Properties Of Non-penetrating Jointed Rock Mass Bridges

The jointed rock mass is one of the most common and important geological bodies.The failure of jointed rock mass is usually composed of joints and rock bridge failure,and the failure characteristics of the joints are the composite failure surface composed of the original joints and the failure surfaces of the rock bridge.Under the action of external load,the rock bridge near the joint surface will crack and extend to the rock bridge,which leads to the weakening of the mechanical properties.The weakening of the mechanical properties of the rock bridge is essentially a mechanical process in which the micro elements in the rock bridge are destroyed under the action of external loads.In this paper,the mechanical properties of jointed rock mass in different failure stages are measured by direct shear test.Based on the theoretical analysis,the mechanical property weakening model of the rock mass bridge is studied,and the influence of the relevant parameters on the weakening degree is analyzed.Based on the rock mass shear exterior facade and interior surface shear test failure analysis,summed up the different connectivity,joints with different topography and different angle of the normal stress on the rock mass damage law.Through the external facade and shear failure surface analysis of rock mass four failure modes: tensile failure and shear failure Zhang La(tensile failure.),shear tensile failure(shear failure and shear failure).At the same time to study the rock mass of six kinds of weakening regional model figure four failure modes corresponding to the next,the tension joint two,tensile shear failure(tensile failure.)two,shear tensile failure(shear)a shear failure,a.Based on the data of the direct shear test,the shear strength of the jointed rock mass is studied by means of the analysis of the different connection rate,different shapes and the different normal pressure.Based on the analysis of the compression strength test data of the core samples in the weakened zone,the weakening law of the non penetrating joints is obtained.Under the same connectivity rate,the higher the fluctuation angle is,the higher the weakening degree is,the lower the connectivity is,the lower the weakening degree is.