结构性黏土边界面模型在FLAC^3D中的开发及隧道施工数值模拟

According to the secondary development platform provided by FLAC^3D, the anisotropic structured clay model(ASCM) is implemented using the coding language of C++. The model is first verified by simulating the undrained triaxial tests on K₀ consolidated Shanghai clay. Numerical simulation of ground loss during tunnel construction is then performed, and the influences of clay structure and adhesive stress on ground surface settlement are analysed. The results show that the user-defined ASCM constitutive model can be used for numerical simulation of 3D tunnels and that the calculated ground surface settlement curves due to tunnel construction agree well with measurements of the centrifugal model tests. The profiles of the ground settlement curve like a "V" with the peak point located near the centre of the two tunnels with a spacing of 1.5D. With increasing the spacing distance of twin-tunnel, the settlement curve shape changes from "V" to "W" with two peak points located above the tunnel axis. Finally, the influence of clay structure on tunnel construction is numerically analysed. It is shown that the influence of clay structure on the ground deformation shape under the disturbance of ground loss in tunnel construction is not significant while that the ground settlement at the tunnel axis increases significantly due to structural deterioration. The influence of the clay adhesive stress on the ground settlement and deformation shape under the disturbance of ground loss in tunnel construction is not significant.