| There are various ways of excavating urban subway tunnels,and the shield tunneling method is increasingly used by various cities in the world because of its construction safety.In the form of subway lines,the form of double-line tunnels is particularly common.However,tunnel excavation will inevitably cause disturbances to the surrounding buildings,bridges,underground pipelines,etc.Once the disturbance exceeds its limit,it will have a serious impact.Therefore,it is very important to study the influence of the shield tunneling method of double-track tunnel on ground surface settlement and the prediction of surface settlement of the tunnel.This paper is based on the research of Hefei Metro Line 2 and Line 3 project.Based on the actual monitoring data of the site and the finite element software Midas/GTS/NX simulation,this paper analyzes the surface settlement caused by shield tunneling in the double-track tunnel and Peck.The parameters of the problem,the main research work is as follows:(1)Firstly,the research methods and results of surface settlement induced by shield tunneling in double-track tunnels at home and abroad are briefly introduced.Then the mechanism of excavation and settlement of double-track tunnels and the factors influencing surface subsidence are analyzed.(2)Presented a number of calculation methods for surface settlement of double-track tunnels by domestic and foreign researchers.To Hefei Metro Line 2civil engineering 03 standard Tongling Road Station-East Second Ring Road Station,East Second Ring Road Station-and County Road Station,Civil Engineering 06 West Jiangxi Road Station-Gaohe East Road Station,07 Standard Qianshan Road Station-Shihe Road Station Interval,08 Standard Qingxi Road-Sili River Road Section Five Project Monitoring Data Based on,and from the well-known Based on the peck formula,the peck formula is transformed,fitted and analyzed to verify the applicability of the Peck formula,and the width coefficient(K)of the settlement trough and the stratum loss rate are calculated to estimate the ground settlement.,verified the suitability of Peck.(3)Using Midas gts nx finite element software to simulate the tunnel construction of Jinzha Road Station-Suzhou Road station station,and using themonitoring data,numerical simulation results,revised Peck estimates to conduct comparative analysis,verifying Based on the rationality of the model,and on the basis of this,the simulation of the settlement of the ground caused by the construction of the double-tunnel tunnels with different center distances,shield excavation methods,distances between different face planes,and the depth of soil cover was simulated.Peck parameters change and its value under many factors caused by surface tunnel subsidence.(4)The prediction of surface subsidence is not the ultimate goal.It is the most important in the whole construction process to feedback the prediction results to how to control surface subsidence after construction and design.At the end of this paper,the change laws of surface subsidence according to the above influencing factors are proposed.Corresponding control measures.This paper analyzes the monitoring data of some sections of Hefei Subway Line2 and Line 3,verifies the applicability of peck,calculates and predicts the peck parameters,so that the surface settlement can be estimated;and then the excavation of double-track tunnels is performed.In the simulation,the factors affecting ground subsidence were analyzed,the ground settlement of double-track tunnels was obtained,and the value of Peck parameters was discussed.The control measures for surface subsidence during the construction of double-track tunnels were proposed.The prediction of surface subsidence caused by the construction of double-track tunnels in Hefei area and the prevention and control of surface settlement induced by construction are instructive. |
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