地铁暗挖车站初支拱盖法开挖工序数值模拟优化

Numerical Simulation and Optimization of Excavation Process of Initial Supported Arch Cover Method for Subway Underground Excavation Station

初支拱盖法地铁车站通常较大,施工中变形控制一直是重点。为优化施工开挖顺序,保证施工安全,结合贵阳地铁施工案例,通过数值模拟进行开挖工序参数优化,并对优化后的施工方案进行长期监测,最终形成以下结论:(1)采用数值模拟的方式提前获知开挖施工过程中的关键控制工序,可以有效预演施工过程,为施工优化提供详实参数;(2)在初支拱盖法施工条件下,采用缩短开挖进尺和增加初支刚度的方式可以减少围岩扰动,增加岩体稳定,有效保证结构安全;(3)实际施工中,临时支撑拆除和核心土开挖引起的地表沉降占总沉降量的近50%,施工中需要严格把控。

The subway station with initial support arch cover method is usually large,and the deformation control has always been the focus in construction.In order to optimize the construction excavation sequence and ensure the construction safety,combined with the construction case of Guiyang Urban Rail Transit,the excavation process parameters are optimized through numerical simulation,and the optimized construction scheme is monitored for a long time.Finally,the following conclusions are formed:(1)the key control procedures in the excavation construction process are obtained by numerical simulation,which can effectively preview the construction process,and provide detailed parameters for construction optimization.(2)Under the construction condition of initial supported arch cover method,shortening the excavation footage and increasing the initial support stiffness can reduce the disturbance of surrounding rock,increase the stability of rock mass and effectively ensure the safety of structure.(3)In actual construction,the surface settlement caused by temporary support removal and core soil excavation accounts for nearly 50%of the total settlement,which needs to be strictly controlled during construction.