| With the development of society and the continuous expansion of urbanization,various traffic problems have emerged in an endless stream.The rail transit mode has played an important role in solving urban traffic congestion.Because it is located in the central area of the city,the construction of the subway tunnel is sensitive to the disturbance of the ground.It is necessary to control the deformation of the ground caused by various constructions and the surrounding rock force within the prescribed range to ensure the safety of construction and protect the daily work of the citizens.Life,property and life safety are not affected.Therefore,the ground surface settlement during the construction of urban rail transit engineering tunnels is deeply studied,and the basic characteristics and laws of surface settlement changes in different regions and geology are sought,which guides the scientific and orderly guidance of the monitoring and measurement of the tunnel construction process.It is of great significance to provide scientific and reasonable and reliable data prediction predictions for subsequent construction steps,as well as targeted and effective control measures in tunnel construction.In this paper,the HW interval tunnel excavation construction of a project of Urumqi Rail Transit is used as the project.Through the investigation of relevant literatures at home and abroad,the influence of the tunnel excavation construction on the ground settlement is summarized.The tunnel engineering finite element method is used to support the project.The construction excavation was simulated and combined with the actual monitoring data to study the ground settlement law caused by HW interval tunnel construction.It mainly includes the following aspects:1.Analyzed and summarized the various influencing factors of surface settlement during the construction of subway tunnel excavation method,summarized and summarized the calculation methods of surface settlement caused by various excavation construction methods,and determined the research ideas and technical routes of this paper.2.According to the nonlinear finite element method of tunnel engineering,based on the simulation method of vertical shaft,cross channel,tunnel excavation,boundary conditions of finite element analysis model,constitutive relations of rock and soil and material,HW interval is established.The finite element analysis model of rock mass-vertical shaft-cross channel-tunnel is simulated by MIDAS/GTS,a finite element analysis software for different construction excavation stages.Through the finite element numerical simulation analysis,the effects of different excavation stages such as shaft,cross channel,tunnel main line and tunnel excavation on the deformation,stress and distribution of surface,stratum and surrounding rock are obtained.3.The numerical simulation results of surface subsidence law and the on-site monitoring measurement results are compared and analyzed,which not only verifies the reliability of the finite element numerical model of complex tunnel construction established in this paper,but also verifies the rationality of numerical simulation results.The subsequent construction of HW interval tunnel process optimization,guiding on-site monitoring program and organization implementation,and safe operation of ground road during tunnel undercut construction provide a scientific basis.The research results and conclusions of this paper can be used as reference for related projects. |
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