| With the rapid passage of time,cities are developing rapidly,and many high-rise buildings are springing up in the streets of today’s cities.At the same time,subway construction has gradually become a symbol of urban modernization.Construction of subway tunnels has become particularly important.In the underground tunnel construction,but also inevitably a special situation,the excavation of the foundation pit is just close to the subway tunnel.In this case,the construction becomes particularly important,and it is possible to cause horizontal or vertical tunnel segment rupture.the subway long-term operation may cause adjacent excavation excavation collapse,uplift,collapse and other casualties.Therefore,it is urgent to analyze the influence of excavation on shield tunneling and to identify the influencing factors.How to consider various factors in excavation has become a problem to be solved.In the analysis of the influence of excavation on the adjacent subway shield tunnel,the influence of excavation on the adjacent shield tunnel is summarized by consulting a lot of literature.The methods used by a large number of scholars in this research field are classified into three categories: formula calculation method,field measurement method and finite element simulation method.Problems and shortcomings in this area were discussed.The deformation principle of tunnel and excavation is also analyzed from two aspects: on the one hand,by summarizing the factors of tunnel failure and classifying its failure types,the paper analyzes the load of tunnel segment under the upper soft soil foundation and the local uniform load on the upper part of elastic foundation beam;on the other hand,it briefly introduces three stress forms of retaining wall,including static earth pressure,active earth pressure and passive earth pressure.The internal force of pile arrangement at different depth is analyzed by calculation software,and the slope after excavation is stable and safe by anti-overturning formula.Chapter 4 models the excavation of a small area near Hefei Metro Line 3 by using MIDAS GTS/NX geotechnical analysis software.This paper introduces the main points of attention of each stage of this modeling in a more simple way,so that some readers can learn from it later,and also introduces some modeling experiences.After the software analysis is completed,the results of deformation of foundation pit bottom plate,retaining pile,double-line tunnel segment and track are compared and analyzed,and each influencing factor is compared by horizontal and vertical displacement values.At the same time,according to the actual situation of theproject and different excavation depth comparative analysis,the corresponding results are obtained.This paper summarizes the influence of foundation pit excavation in the adjacent subway tunnel,and summarizes the following points: deformation of foundation pit support structure,surface settlement after foundation pit excavation,foundation pit bottom uplift,and also summarizes and expounds several major causes and influencing factors of foundation pit deformation in detail.Finally,through these main factors,including the horizontal distance from the center of the tunnel to the center of the foundation pit,the excavation near the tunnel(the best excavation depth is 3 meters)to obtain the deep foundation pit of different depth to analyze the influence on the adjacent double-line tunnel,the control variable method is used to establish different engineering models for more detailed analysis.Figure[62]table[11]reference[50]... |
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