| With the acceleration of the domestic urbanization process,the quality of people's living standards has inproved rapidly,and the mode of travel has been continuously transformed,resulting in urban ground traffic congestion.In order to improve the ground traffic pressure,many cities began to develop underground rail transit. Quasi-rectangular shield is a novel shield tunnel It has many advantages over traditional circular tunnels,high utilization of underground space,and reduced demolition of ground buildings.Shield method is the most commonly used construction method at present,but underground pipelines of various purposes are buried underground.Shield construction will have certain impact on undergound pipelines,deformation,damage or even cracking,etc.People's lives and property are safe.1.This paper mainly focuses on the indoor model test of the influence of uasi-rectangular shield tunnel construction on adjacent underground pipelines.The odel test study is carried out by changing the relative position of pipelines,pipeline epth,soil loss rate and using non-continuous pipelines and damaged pipelines. nalyze the regular changes of underground pipeline settlement and bending moment in the model test.In this paper,the surface and deep soil settlement are monitored,and the variation law of soil in shield construction is obtained.The main work of this paper is as follows:2.The model test results show that before the measuring point of the uasi-rectangular shield,the pipeline settlement and bending moment are small,and he variation range is small.When the shield passes through the pipeline measurement oint,the pipeline settlement increases sharply and the maximum settlement occurs ue to soil loss.It is located directly above the axis of the tunnel and obeys the aussian distribution.It has a "V" shape and the bending moment responds obviously. t is distributed in an "N" shape.The pipeline settlement and bending moment remain table until the shield is completely removed.The settlement of the deep soil is symmetrically distributed about the axis of the tunnel.As the depth of the soil ncreases,the gap between the maximum settlements of the soil increases.3.Comparing the relative factors of pipe and tunnel relative position,pipeline depth and soil loss rate,the settlement of pipe tunneling obliquely is slightly larger than the vertical condition of pipe tunneling,and the negative bending moment is closer to the tunnel direction than the vertical working condition.Parallel working conditions are least affected;the greater the buried depth of the pipeline,the larger the settlement and bending moment values,the greater the impact on the pipeline;the soil loss is a major influencing factor affecting pipeline deformation and soil settlement,and has a significant impact.Pipeline settlement and bending moment response.4.In order to simulate the actual working conditions more realistically,this paper uses non-continuous pipelines and damaged pipelines to carry out model test research,and obtains the test results:the results of non-continuous pipeline test are not obvious compared with continuous pipelines,pipeline settlement and bending moment data.The numerical value is relatively small,which is more in line with the actual working conditions.On the basis of non-continuous pipelines,the experimental study is conducted using broken pipelines.For pipeline settlement,the data of discontinuous damaged pipelines and non-continuous pipelines are very small.For the bending moment,the non-continuous damaged pipelines have a greater response to negative bending moments.Figure[61]Table[5]Reference[63]... |
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