河漫滩地区深基坑地下水控制方法研究

Study on Groundwater Control Methods for Deep Foundation Pit in Floodplain Area

以汾河漫滩地区砂土与黏性土交互沉积地层中的两个典型深基坑工程为例,研究不同地下水控制方法的降水效果;对地下水位变化、基坑周边地表沉降进行分析。结果表明:在地下水位较高的汾河漫滩地区开挖地铁车站基坑时,采用坑外降水方案是安全可行的;对于同等规模的基坑工程,采用坑外降水方案可在一定程度上缩短工期、节省造价;相比坑外降水方案,采用有止水帷幕的坑内降水方案可显著降低对周边环境的影响,总抽水量减少约60%,降水影响半径减小约70%,地表沉降减少约45%。

Taking two typical deep foundation pit projects in the interactive sedimentary strata of sand and clayey soil in the floodplain area of Fenhe River as the examples,the precipitation effects of different groundwater control methods are studied.The changes of groundwater and the ground subsidence around the foundation pit caused are analyzed and studied.The results show that the out-of-pit precipitation is safe and feasible for the subway station in Fenhe floodplain area;for the foundation pit of same scale,the out-of-pit precipitation can shorten the construction period and save the cost to a certain extent;compared with the out-of-pit precipitation,the in-pit precipitation with waterproof curtain can significantly reduce the impact on the surrounding environment,the total pumping volume is reduced by about 60%,the precipitation influence radius is reduced by about 70%,and the ground subsidence is reduced by about 45%.