Action zoning in clay stratum caused by tunnel excavation

Aiming at analyzing the tunnel excavation problem in representative silty clay stratum in Beijing,triaxial consolidation drainage tests were carried and the mechanical characters under different stress paths were analyzed.Then,a two-dimensional numerical tunneling model with general engineering parameters was established.The stress of grid points and Gauss points was calculated,and the stress changes of typical points were tracked.After that,the action zones of the stratum were classified,and the final ground settlements which consider action zones were calculated by turning the test results of strength into the corresponding action zone model.At last,a centrifuge test model was constructed,and the final surface settlement value was recorded.By contrasting test results with simulation results,the correctness of action zoning in silty clay stratum was verified.