Analysis Of Soil Deformation Caused By Large Diameter Pipe Jacking Construction In Sand Stratum

With the rapid development of urban construction in China,the development and utilization of underground space has received more and more attention.As a kind of undercut construction technology,the pipe jacking method has been more and more widely used in urban infrastructure construction.However,due to the characteristics of the pipe jacking construction,disturbances are inevitably generated during the construction process,causing deformation of the surrounding soil.If the deformation is too large,it may cause damage to surrounding structures and underground pipelines,and may even bring huge Economic losses and the safety of personnel.Therefore,it is of great significance to predict and control the soil deformation caused by pipe jacking construction.On the basis of previous studies,I used theoretical calculation analysis and numerical simulation analysis to study the soil deformation law caused by large-diameter pipe jacking construction and its influence on the surrounding environment and the influence of various parameters on soil deformation..The main research contents and conclusions of this paper are as follows:(1)The elastic deformation analysis method is used to calculate the deformation and settlement of the soil in the upper part of the top pipe caused by the large-diameter construction of the sand layer.The causes of soil deformation caused by pipe jacking construction are analyzed.The soil displacement caused by the three main factors of top thrust,friction and soil loss is calculated by elastic mechanics.The direct integral method is used to solve the problem.The results obtained are compared with the measured data.(2)Numerical simulation of the engineering example is carried out by using MIDAS GTS finite element software.It is assumed that the soil layer is homogeneous and isotropic,and the soil is numerically simulated by Moore-Coulomb theory.Comparing the simulation results with the measured data and theoretical calculation results,it is concluded that the law of soil deformation caused by large-diameter pipe jacking construction is similar to thenormal distribution trend,and the influence range is about 1.5h~2h.,verify the correctness of the theoretical calculation results.(3)Analyze the impact of pipe jacking construction on adjacent viaducts.When the top pipe excavation surface is gradually approaching the bridge structure,the lateral displacement of the bridge pile foundation gradually increases.When the top pipe excavation face reaches the bridge structure,the lateral displacement reaches the maximum value,and then the pipe jacking is excavated.As the surface gradually moves away,the lateral displacement of the bridge structure rebounds,and its deformation value tends to decrease gradually.(4)Study the influence of various relevant factors on soil deformation during pipe jacking construction,including construction parameters,soil properties,soil depth,pipe diameter and pipe shape,and draw various factors under different variables,pipe jacking construction The deformation law that causes the deformation of the soil.