基坑疏干抽排对区域水文地质的影响分析

Research on the influence of foundation pit drainage and drainage of an enterprise headquarters on regional hydrogeology

研究疏干抽排条件下的基坑地下水变化状况对掌握水资源变化量与避免地面沉降的发生具有重要意义。本文以某建设项目为例,依据GMS地下水数值模拟技术研究了基坑疏干抽排对周边地下水水位、水资源量、地面沉降及其他方面的影响,论证抽排水的合理性,为实现水资源可持续利用、城市可持续发展提供科学理论依据。结果表明:在疏干抽排条件下,基坑周边水位降深随着与基坑距离增加而逐渐变小,基坑降水对周边水位影响范围有限。当基坑抽排水662 d时,可出水总量为16 421.10 m^(3)。其中,潜水与第一微承压含水层可出水量分别为6 900.81 m^(3)、9520.29 m^(3),表明基坑抽排水量基本合理。在基坑抽排水662 d后,基坑外水位降深为0~0.2 m,基坑外引起的地面沉降最大值为0.005 4 m,且最大沉降量主要集中于基坑边缘。分析结果可为类似项目提供参考。

It is of great theoretical and practical significance to study the variation of groundwater in foundation pits under the condition of dredging and draining for grasping the variation of water resources and avoiding the occurrence of land subsidence.Taking a construction project as an example,this paper studies the influence of foundation pit drainage and drainage on the surrounding groundwater level,water resources,land subsidence and other aspects based on GMS groundwater numerical simulation technology,and demonstrates the rationality of pumping and drainage.Sustainable utilization and sustainable urban development provide scientific theoretical basis.The research results show that:under the condition of dredging and drainage,the water level around the foundation pit decreases gradually with the increase of the distance from the foundation pit,and the influence range of the foundation pit precipitation on the surrounding water level is limited.When the foundation pit is pumped and drained for 662 days,the total water output is 16421.10 m^(3).Among them,the water yield of the submersible and the first micro-confined aquifer are 6900.81 m^(3) and 9520.29 m^(3),respectively,indicating that the drainage volume of the foundation pit is basically reasonable.After 662 days of drainage from the foundation pit,the water level outside the foundation pit draws down to 0.0~0.2 m,and the maximum land subsidence caused outside the foundation pit is 0.0054 m,and the maximum subsidence is mainly concentrated at the edge of the foundation pit.The analysis results can provide reference for similar projects.