The Constitutive Model of Chang 7 Shale Considering Initial Damage

摘要

In this paper,the Chang 7 shale is taken as the research object.In view of the shortage of initial damage in the shale constitutive model,a Chang 7 shale constitutive model considering initial damage is established.Through scanning electron microscopy and CT scanning experiments,it can be seen that shale itself has a large number of mesoscopic damage,and the shale has different initial damage through ABAQUS simulation.The results show that the existence of the initial damage makes the shale more easily broken and has a great influence on the displacement field and stress field;according to the theory of continuous damage and the statistical intensity theory.In this paper,a statistical damage constitutive model for uniaxial compression of Chang 7 shale considering initial damage is established.The uniaxial compression test of Chang 7 shale is carried out.According to the failure pattern,it is found that the failure of the shale core along the parallel bedding direction is mainly caused by the joint action of shear and splitting failure.The theoretical model curve considering the initial damage fits well with the experimental data curve,which verifies the accuracy of the model.