| In recent years,road traffic congestion in first-tier and second-tier cities has become increasingly serious.Underground rail transit,as an effective method to alleviate congestion,is under construction in a large area.Among them,shield method is one of the most important construction methods.It has the advantages of safe excavation and lining,fast tunneling speed,and does not affect the ground traffic and facilities,but there is a common problem frequently occurring in the construction process: the floating of tunnel lining.At present,many scholars pay more attention to the research on the control of tunnel lining floating in soft strata,but less on the control of tunnel lining floating in water-rich hard rock strata.However,with the rapid development of urban subway construction,in the actual shield construction process,it is often encountered that the water-rich hard rock stratum tunnel lining floating.If not properly controlled,it will seriously affect the engineering quality of tunnel lining structure and cause irreparable losses.Therefore,The floating of tunnel lining in the water-rich hard rock strata is also worthy of attention and research.First of all,this thesis collectes relevant literature on tunnel lining floating of shield tunnel to understand the mechanism of tunnel lining floating,factors affecting tunnel lining floating and control measures of tube sheet floating from three aspects of theoretical research,experimental research and technical research.Then,the thesis summarizes the five main reasons related to the floating of tunnel lining in the water-rich hard rock stratum,and analyzes the influence of static floating,dynamic floating and attitude control on the floating of pipe slices.In addition,taking the shield tunneling construction of dashu east road station and xiuhu road station of the south extension line 2 of a city rail transit line as the engineering background,the precontrol measures of tube piece floating are put forward.Then,the shield tunnel in the water-rich hard rock area in the engineering case was selected,and the finite element model of the shield tunnel in the area was established by using ABAQUS simulation analysis software to simulate the tunnel construction process.After post-processing,the relevant data of tunnel lining floating was obtained and analyzed,then,according to the result of simulation optimization control counter measures,get 4 tunnel lining floating water hard rock stratum of the control method and the actual monitoring means to verify the effectiveness of the control measures,according to the application effect and the actual construction process control measures for optimizing again,until The floating of tunnel lining in the water-rich hard rock strata is controlled in a reasonable range.This thesis takes shield tunneling as an example,and through theoretical and practical research,the obtained control measures for tunnel lining floating in water-rich hard rock strata will be of certain reference value for similar projects in the future. |
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