基于安全系数的地铁车站衬砌优化设计探讨

实际工程中初衬受力与变形很大因而初衬会进入塑性,应将初衬视作弹塑性加固材料进行设计计算。结合一个青岛地铁车站衬砌的设计计算,将强度折减法应用于隧道稳定性分析。考虑衬砌施作时的围岩应力释放率影响,利用强度折减法计算隧洞围岩及衬砌的安全系数。初衬后围岩安全系数不应小于1.15~1.20,如果围岩安全系数小于1.30,此时二衬将承受一定荷载。二衬安全系数与初衬后围岩安全系数的乘积应大于2,以确保二衬安全。通过计算可以定量的确定初衬和二衬的结构尺寸,确保隧洞安全并合理降低成本。

Discussion on Lining Optimization Design of Subway Station Based on Safety Factor

There load and deformation of initial lining are big in practical engineering,so the lining may work in plastic state.The initial lining should be taken as elastic-plastic reinforced material in calculation.Based on the lining design calculation of a station in Qingdao subway,the strength reduction method is applied to the analysis of tunnel stability.Considering the influence of stress release rate of surrounding rock on lining,the safety factor of tunnel surrounding rock and lining is obtained by strength reduction method.The safety factor of surrounding rock with initial lining should not be less than 1.15～1.20.If the safety factor is less than 1.3,the secondary lining will support a certain amount of load.The product of safety factors of the initial lining and the secondary lining should be greater than 2 to ensure the secondary lining safety.The structure size of the initial lining and the secondary lining can be determined through calculation,and the tunnel safety can be ensured and the cost can be reduced reasonably.