某地铁车站基坑围护结构变形过大的实测与计算分析

Monitoring and Numerical Inversion Analysis of Excessive Deformation of Retaining Structure in Foundation Pit of a Subway Station

对于围护结构出现变形过大、报警情况的地铁车站基坑,安全余量和危险程度通常不易定量判断,针对此种情况,对广州某地铁基坑位移报警工况进行了全过程数值反演计算,采取墙背土压力随开挖过程而变化的增量法,利用监测结果反演了计算参数并进行了验证,利用验证后的参数进行计算,得到了正常和报警等不同工况下的内力和变形,得到一些围护结构变形过大时的变形特征和规律,可以对工程的危险情况进行定量判断,取得了常规方法不能达到的较好效果,对类似设计具有一定参考价值。

For the subway station foundation pit with excessive deformation and alarm,the safety margin and danger degree are usually difficult to quantitatively judge.In this paper,the whole process numerical inversion calculation of the displacement alarm working condition of a subway foundation pit in Guangzhou is carried out,and the incremental method of the earth pressure on the back of the wall changing with the excavation process is adopted.The calculated parameters are inverted and verified by the monitoring results.The internal forces and deformations under normal and alarm conditions are calculated by using the validated parameters.The deformation characteristics and laws of some envelope structures are obtained when the deformation is too large.The dangerous situation of the project can be quantitatively judged and the conventional formulas are obtained.The good results that can not be achieved by the conventional methods and some conclusions are obtained.It has certain reference value for similar design.