Research On Foundation Pit Construction Technology Of Yiliulu Utility Tunnel Project In Southern New Town Of Changchun

Based on the comprehensive utility tunnel engineering of no.b6 road,new town,south of changchun city,this paper conducts an in-depth study on the key construction technologies of pipe gallery deep foundation pit by combining the construction,on-site monitoring and numerical simulation of pipe gallery deep foundation pit.The main research contents are as follows:(1)In this paper,relying on the comprehensive utility tunnel engineering,of no.b6 road,new town,south of changchun city,based on regional geology and climate conditions,and combined with the difficulty of the utility tunnel deep foundation pit engineering on the pipe rack,summarizes the key construction technology of deep foundation pit,put forward the utility tunnel construction of deep foundation pit precipitation larsen steel sheet pile construction and the key technology of excavation,can provide a reference for similar projects(2)Based on the geological and climatic conditions of changchun area,combined with the characteristics of the foundation pit support structure,the monitoring scheme of the foundation pit support structure was developed.This monitoring program adopts the method of combining automatic monitoring with manual monitoring.The principle and implementation method of various monitoring contents are comprehensively analyzed and expounded in this paper,which lays a foundation for efficient monitoring and correct analysis of safe foundation pit construction.(3)Through in-depth analysis of the monitoring data of the deep foundation pit of the tunnel,the change rules of monitoring targets with the construction progress are obtained,and the change trend is analyzed.(4)Through the analysis of the steel support form of foundation pit at K0+547 miles of no.b6 road,new stown,south new town of changchun(fangcaojie-no.3 road),discrete element software PFC is used to establish a discrete element simulation model.Through numerical simulation and analysis,the horizontal displacement,vertical displacement and axial force of steel support of retaining piles under three working conditions are obtained.(5)The simulation results are compared with the measured data,and the simulation results are basically consistent with the measured data.The correctness and effectiveness of monitoring data and numerical simulation results of this project are verified by each other,and the reliability of PFC simulation for dynamic excavation of foundation pit is also demonstrated,which can provide technical guidance and help for similar projects.To sum up,this paper adopts the method of combining tunnel deep foundation pit construction,on-site monitoring and numerical simulation to study the deformation and stress characteristics of the overall structure of tunnel deep foundation pit in the construction stage,and obtains beneficial results,which can provide reference for the optimization design and structural analysis of similar projects.