Study On Design And Construction Method Of Retaining Structure For Tunnel Foundation Pit With Confined Water Stratum

Design and construction of confined water foundation pit are one of the hot and difficult problems in geotechnical engineering.Balancing the deformation and cost of foundation pit is a subject that engineers are exploring.On the basis of summing up a large number of research results and engineering experience,the paper analyzed the deformation of tunnel foundation pit with confined water in Suzhou which taking the Renmin Road tunnel as the background.At the same time,we studied the deformation factors of foundation pit using Midas GTS NX finite element software.The main work and contents of this paper are as follows:Summarized the research methods of the design of foundation pit,analyzed the seepage theory and the research status of the confined water foundation pit.Systematically expounded the deformation regularity and mechanism of foundation pit,and summarized the common form of retaining structure of confined water foundation pit combining with the design and construction experience.Analyzed and compared the safety grade standard specification and deformation control standard.Collected deformation monitoring data and establish the database.Put forward the proposed value of the deformation control index of the tunnel foundation pit in Suzhou on the basis of summarizing and summarizing the deformation data.Summarized the hydrogeological features of Suzhou,and divided the foundation pit with confined water into 4 typical forms.Utilizing the micro confined water foundation pit form which can represent the highway tunnel foundation pit in Suzhou,combined with the Midas GTS NX finite element software,to research and analyze the impact of hydrological factors,design factors and construction factors on the deformation of foundation pit.Put forward measures to control the deformation of foundation pit and provided the basis for the design and construction of this type of foundation pit.Summarized the key technologies of the foundation pit engineering of Renmin road tunnel from the selection,design and construction of the retaining wall.In addition,some measures are put forward to control the deformation of the foundation pit and protect the subway section tunnel,and the effectiveness of the measures was proved by the finite element simulation.