Study On The Influence Of Foundation Pit Excavation Dewatering On Surrounding Buildings

In the research of domestic and foreign literature and practical investigations of multiple foundation pit projects in Zhengzhou City,it was found that when the depth of the foundation pit is not large(less than 10 meters),the surrounding buildings are far away from the foundation pit,and the groundwater level is relatively shallow,in the selection of actual engineering design schemes for foundation pit support,it is generally to save costs,and examples of using soil nail support without waterproof curtains are not uncommon.But in this situation,how much impact does excavation and dewatering of foundation pit soil nail support have on surrounding buildings? How to evaluate this impact? For many years,it has been a problem that needs to be considered in the design,construction and monitoring process of on-site foundation pit engineering.This article takes a certain foundation pit in Zhengzhou City as the engineering background,and uses a combination of design calculation using Lizheng software,numerical simulation using finite element software,and theoretical formula calculation to study the impact of soil nail support excavation dewatering on surrounding buildings.The main research content of this article includes the following aspects:(1)Design and calculate the support structures of sections 4-4 on the north side of the foundation pit and section 7-7 on the west side of the foundation pit using Lizheng software.Through local tensile verification,internal stability verification,concrete surface calculation,and anti uplift stability verification,the results show that these two soil nail support profiles meet the requirements of the design specifications.(2)Using the finite element software MIDAS GTS/NX,numerical simulation was conducted on the construction process of the foundation pit.The physical models of the teaching building on the west side of the foundation pit and the residential building on the north side of the foundation pit were built to participate in the analysis.The horizontal and vertical displacement of the soil mass,the horizontal displacement and settlement of the teaching building and residential building,and the main tensile strain of the longitudinal wall of the teaching building and residential building were analyzed under conditions such as excavation and precipitation To study the impact of foundation pit excavation dewatering on teaching and residential buildings,the variation laws of pore water pressure and soil nail axial force are used.(3)Through theoretical research on ground settlement induced by foundation pit excavation dewatering,a simplified algorithm formula for ground settlement caused by foundation pit dewatering considering building loads is derived.Combined with engineering examples,the settlement laws of different parts of the foundation pit and surrounding buildings are obtained.(4)The on-site monitoring of the foundation pit was conducted,and a monitoring plan was provided.The monitoring results were analyzed and compared with the numerical simulation results.