3D ELASTOPLASTIC NUMERICAL SIMULATION OF SURROUNDING ROCK DISPLACEMENT IN SOFT SURROUNDING ROCK SECTION DURING CONSTRUCTION PROCESS
软弱围岩段隧道施工过程中围岩位移的三维弹塑性数值模拟

The tunnel in soft surrounding rock with maximum buried depth was modeled based on Bijiashan Tunnel of the 2nd Project of Yuqian Expressway; and three-dimensional elastoplastic numerical simulation is conducted for construction process. Variation laws and magnitudes of settlement and horizontal displacement in designated cross section are attained. Computing results show that the maximum range of influence on the settlement and horizontal displacement is within 3 meters before and after the designated section and magnitudes account for two-third of gross amount, and the influence of upper bench excavation is obviously greater than that of lower bench; and the settlement and horizontal displacement have accomplished 40% before heading face is excavated; and the area with concentrated displacement is 3 -5 m away from the tunnel wall. In addition, comparison of arch crown settlement and horizontal convergence of haunch between in-situ testing data and computing ones shows that the variation laws fit preferably.