地铁车站深厚地连墙支护下的基坑降水工艺研究

Research on dewatering technology of foundation pit excavation under deep connecting wall support of subway station

以某地铁车站基坑工程为例,针对该地铁站基坑开挖地下水时亟需降水,对车站顶板防水、结构渗漏有很大影响的情况,设计使用三维渗流模型,对整个渗流区进行离散后,采用向后差分法将上述数学模型进行离散,得到了数值模型,设计在3轴—25轴区域坑外布置③2T层降水井40口(其中22口为备用兼观测井),并由此计算预测降水引起的地下水位的时空分布,为类似含水条件下的地下连续墙地铁基坑降水提供了类似的经验参考。

Taking a subway station foundation pit project as an example,the underground water excavation of the subway station is in urgent need of precipitation,which is greatly influenced by the waterproof roof and structural leakage of the station.The three-dimensional seepage model is used in the design,the whole seepage zone is discretized,and the above mathematical model is discretized by backward difference method,then the numerical model can be obtained.In the design,40 precipitation wells(22 of which are standby and observation wells)in the③2T layer are arranged outside the pit in the 3-25 axis area,and the spatio-temporal distribution of groundwater level caused by precipitation can be calculated and predicted.It provides similar experience reference for dewatering of underground diaphragm wall subway foundation pit under similar water condition.