Research On The Impact Of Foundation Pit Dewatering On The Surrounding Environment

To guarantee the safety of foundation pit engineering,dewatering of foundation pit has been taken.However,dewatering certainly will have an impact on the surrounding soil settlement,adjacent buildings,also dewatering changes the seepage field would caused the interaction of the surrounding stress field,increased the difficulty of accurate prediction of the results.This article is based on the background of a subway station excavation project in Beijing,using Midas GTS finite element software with seepage stress coupling analysis,study the influence of foundation pit dewatering on the surrounding environment,the main results are as follows:First,discuss the domestic and foreign the theoretical research status of the influence of the foundation pit dewatering on the settlement of the soil around the pit and the surrounding environment in detail.Second,summarizes and analyzes the harm of groundwater seepage on foundation pit engineering and the types of foundation pit dewatering and applicable conditions,theoretical analysis of the mechanism of the influence of precipitation on the surrounding environment,and gives the calculation method of ground subsidence.Third,elaborated the Midas GTS finite element software used in the foundation pit engineering involves the seepage analysis and seepage stress coupling analysis basic principle,the material constitutive model in the software and the similar project modelling analysis method.Forth,The actual monitoring results and the numerical simulation results under different conditions are compared and analyzed.According to the research:when the cumulative settlement of the soil outside the pit is taken as the research object,the case three has the best fitting effect.The settlement outside the pit caused by precipitation is about 35% of the total settlement,caused by excavation is about65%.With the increase of horizontal distance,the cumulative settlement value increases first and then decreases,the maximum value is about 1.16 times of the excavation depth,the influence of precipitation must be considered in the analysis of foundation pit engineering with precipitation.Taking the foundation pit heave as the research object,the first elastic bottom uplift,with precipitation increasing excavation depth into plastic upheaval.At the beginning,the bottom of the foundation pit's uplift is elastic,with the increase of excavation depth,it changes to plastic uplift.Based on the deformation and internal force of the adjacent pile foundation,the settlement of the pile decreases with the increase of the distance of the foundation pit,which forms the differential settlement,and causes the inclination of the building.Taking the horizontal displacement of diaphragm wall and the internal force of steel shotcrete for research objects,with the increase of excavation depth,the deformation of diaphragm wall is characterized by smal at both ends and large in the centre;The maximum value of the axial force of steel shotcrete is similar to the horizontal displacement of the retaining structure,The variation of axial force is consistent with the deformation of retaining structure.