Deformation Prediction Of Adjacent Pipelines By Foundation Pit Excavation At Xi'an Subway Station

With the intensification of the urbanization process,the foundation pit project and the surrounding environment have gradually attracted widespread attention.Excavation of the foundation pit will change the initial stress state of the soil,accelerate the change trend of soil displacement,and cause damage to the surrounding environment of the foundation pit.Urban underground pipelines are a prerequisite to maintain the normal operation of urban foundation functions.It is of great significance to predict the deformation of underground pipelines adjacent to the foundation pit.It can improve the design of the foundation pit engineering and clarify the shortcomings in the construction process.Has a certain practical value.In this paper,Midas GTX finite element analysis software is used to carry out a full range of numerical simulations on the foundation pit engineering of the adjacent underground pipeline.The displacement change of the pipeline under the coupling of different factors is explored.The principle of orthogonal experiment design is used to discover the influencing factors on pipeline deformation In order of importance,suggestions for optimization of related parameters are proposed,and a deep foundation pit in a subway station in Xi'an is used as an example.The past monitoring data is used to predict and analyze the subsequent deformation of the construction with the help of neural network and finite element.The main research contents of this article are as follows:Explore the stress state and deformation mechanism of the subway station foundation pit construction process,summarize the causes of the foundation pit deformation,summarize and summarize the foundation pit safety control standards,excavate the deformation and stress mechanism of the underground pipeline,list five modes of pipeline damage,and analyze For the cause of damage,the standard for deformation control of adjacent pipelines by foundation pit excavation was proposed.The three-dimensional finite element analysis software is used to construct a three-dimensional simulation model of the foundation pit and its surrounding environment.The horizontal and vertical displacement rules of the pipeline at various depth positions and different burial distances are analyzed and predicted.The effects of displacement changes on the pipelines adjacent to the foundation pit,List the corresponding method of pipeline safety protection.With the excavation of a deep foundation pit in a subway station in Xi'an as the engineering background,the horizontal distance from the pipeline to the foundation pit,the buried depth of the pipeline,the vertical spacing of the support,and the stiffness of the retaining structure were set as variables,and the maximum horizontal and vertical displacement of thepipeline was used as the assessment index.,Select the correct and appropriate orthogonal table,and use the three-dimensional finite element analysis software to calculate the numerical simulation results under different combinations and conditions,perform range analysis and variance analysis on the results of each group,and discover the four variables that rank the significance of pipeline deformation.,Put forward parameter optimization suggestions,find out the combination of variables that minimize the pipeline deformation.Using the Elman neural network prediction model,the sample data is selected as the difference between the measured data and the numerical simulation value,the difference between the two data in the subsequent stage is predicted,and then the numerical simulation value is added to obtain the revised predicted value.Comparing the three data,the corrected predicted value reduces the error of the numerical simulation value by half.The research results have a certain reference function for the prediction of the deformation of the adjacent pipeline induced by the excavation of the foundation pit.