Research On The Effect Of Zonal Excavation Of Narrow,Long And Deep Foundation Pit On Settlement Of Adjacent Buildings

With the acceleration of urbanization in our country,the development speed of urban rail transit is getting faster and faster.Subway is an important link in rail transportation.It is usually located in the prosperous area of the urban area,and the surrounding environment is complex and requires high protection.In order to study the effect of zonal excavation of narrow and long deep foundation pits on the settlement and deformation control of adjacent buildings,based on the deep foundation pit project of Diejiao Station of Foshan Metro Line 3,the monitoring data of settlement and deformation of surrounding buildings during zonal excavation were collected and sorted.At the same time,the three-dimensional finite element model of the subdivision and overall excavation of the deep foundation pit of the station was established,and the effect of subdivision excavation on controlling the settlement and deformation of surrounding buildings was compared and analyzed.The main research contents and research results include the following aspects:(1)The existing deep foundation pit theories,including the deformation of the foundation pit itself,the ground settlement outside the pit,the influence of the foundation pit excavation on the adjacent buildings,and the foundation pit divisional excavation theory are studied.(2)Relying on the deep foundation pit project of Diejiao Station of Foshan Rail Transit Line 3,by establishing the numerical model of foundation pit excavation,the displacement of the foundation pit enclosure structure and the settlement of surrounding buildings were analyzed,and the result was obtained.Displacement changes of protective structures and buildings.(3)By comparing the numerical simulation results of subdivision excavation with the on-site monitoring data of Diejiao Station,it is found that the deformation of the enclosure structure,the surface settlement and the settlement of adjacent buildings during the excavation of the foundation pit are basically consistent with the on-site monitoring data.This verifies that the parameters selected for numerical simulation are reasonable and feasible.(4)Continue to use the relevant parameters selected for subdivision excavation to establish the numerical model of the overall excavation of the foundation pit.When the excavation is carried out,it has a significant impact on the settlement and deformation of the building near the middle of the long side of the foundation pit.By setting up partition walls to excavate in different areas,the space effect of the foundation pit can be fully exerted,and the influence of the "long side effect" on the settlement and deformation of the building can be reduced.It can provide reference for the design and construction of similar projects in the future.