THE PREDICTION OF ELASTIC-PLASTIC STATE OF THE SOIL MASS NEAR THE TUNNEL WITH TAKING INTO ACCOUNT ITS STRENGTH ANISOTROPY

In this work the strength and deformation characteristics of clay formations in the underground space of megacities are investigated. It is found that they have anisotropy of the mechanical characteristics, which are directly connected with the processes of soil formation. The clay layered mass is seen as a transversely isotropic medium, the strength and deformation characteristics of which depend on the direction of load application relative to the plane of bedding. From the experimental results we have obtained indicators of the strength and deformation characteristics which are used as model parameters of a transversely isotropic medium in mathematical and numerical modeling. We have developed geomechanical model of a plastically anisotropic soil mass and estimated the influence of anisotropy on the limiting condition of the soil mass around the tunnel. In order to solve the problem the method of small parameter and finite element method have been used.