某强透水承压含水地层基坑工程降水方案比较分析

Comparative analysis of dewatering scheme of foundation pit engineering in strong permeable water-bearing stratum

通过结合实际工程案例,分析了承压含水层降水后,承压水位的变化趋势,及降水对地面沉降与现状道路沉降的影响。通过数值模拟建立了存在局部深坑的综合基坑的降水方案模型,分析结果表明:通过在局部深坑处设置止水帷幕可将深坑内降水井数目减少一半,坑边地面沉降值减少约53%,现状路面沉降减少约23%;同时,止水帷幕进入坑底以下10 m后,坑底水位方可满足降水要求;但该深度大于10 m后再加深止水帷幕对坑底及坑边承压水位降深影响逐渐减小。因此,推荐降水方案为在局部深坑处设置止水帷幕,帷幕进入坑底以下10 m。

In this paper,the variation trend of underground water level and ground subsidence after dewatering were analysed combined with engineering case.The analytic target of this paper was a comprehensive foundation pit with local deep pits.By means of numerical simulation,the dewatering scheme model of the foundation pit was established.The analysis results showed that by setting waterproof curtain around the local deep pit,the number of dewatering wells in the deep pit can be reduced by one time,the ground settlement can be reduced by about 53%,and the road settlement around the pit can be reduced by about 23%.Meanwhile,the dewatering requirements can be met after the waterproof curtain enters 10 m below the pit bottom.However,when the depth was greater than 10 m,the influence of the water stop curtain on the bearing water level at the bottom and edge of the pit decreased gradually.Therefore,the recommended dewatering Scheme for this foundation pit was to set the waterproof curtain around the local deep pit,and the curtain entered 10 m below the pit bottom.The calculation and analysis process in this paper can provide reference for similar projects in the future.