Numerical simulation and optimization on deformation law of deep foundation pit of subway station

Taking the deep foundation pit engineering of Shijidadao station of Lanzhou subway 1#lines first-stage project as background.The project's surroundings,geological and hydrological conditions of the proposed field and the retaining structural type was introduced.According to the engineering characteristics,the project was divided into four typical operating conditions,the deformation rules of deep foundation pit at subway station in tunneling that the supporting structures is choosed by the bored piles and interior support were simulated with the FLAC3D,The horizontal deformation of the retaining structures, the axial force changes of steel support,the settlement law and the influence sphere of surrounding soil were analyzed.The design alternative of supporting of the pit engineering was optimizated according to the effect of supporting position on deformation of deep foundation pit.The improved design had a better performance in deformation control during the excavation comparison than the original design.