Performance Analysis And Experimental Research On Working Well Of Pipe Gallery

Underground pipe gallery is an important infrastructure of a modern city.As an important hub connecting tunnels,pipe gallery work wells have a great influence on the stable operation of underground utility tunnel.Because it is deeply buried in the soil,the structure depth is larger than the plane size,and it has a more obvious spatial effect.At the same time,there are complex interaction problems between the pipe gallery working well and the soil during use,which are affected by many factors.When analyzing the performance of working wells,how to select reasonable parameters for structural and soil analysis models is worthy of in-depth study.In this paper,combined with the 220 k V cable tunnel project of Gaishan～Dongtai,indoor model tests and three-dimensional finite element numerical simulation methods are used to analyze and study the bearing and deformation laws of working wells under horizontal and vertical loads.The main work of this paper has the following aspects:A rectangular working well model was designed based on similar principles,and indoor model tests were carried out with sand as the backfill material.During the test,a self-designed test device was used to measure the deformation of the working well,well wall stress and earth pressure,and explore the bearing and deformation laws of working wells under the action of 5 sets of uniformly distributed loads are described.Using ABAQUS finite element analysis software to carry out the numerical simulation of the corresponding indoor model test of the working well,and further study the earth pressure distribution,displacement change and stress distribution law behind the wall of the working well under different loads.The results of the numerical analysis and the test are compared to verify the accuracy of the model test results and the effectiveness of the modeling method.Using the validated modeling method,based on the working shaft structure in the 220 k V cable line tunnel project of Gaishan～Dongtai,a three-dimensional finite element numerical analysis model considering the soil-structure and tunnel-structure interaction was established,and the length and width were studied.The load-bearing and deformation characteristics of working wells with ratios of 1:1,1.5:1,and 2:1 under normal use conditions.Based on the calculation results,structural reinforcement calculations are carried out,and representative working wells are selected to study the pair of surrounding load arrangements.The influence of structural load-bearing and deformation characteristics.The research results show that as the aspect ratio increases,the deformation and stress of the working well gradually increase,the spatial effect becomes more obvious,and the structural reinforcement ratio also increases;as the distance between the vehicle load and the working well increases,the load affects the working well.The influence of deformation and stress is gradually reduced;the increase of pile load and traffic static load at the side of the well will lead to the increase of deformation and stress of the working well;the three kinds of loads have almost no effect on the stress and deformation of the bottom of the working well.Based on the working well with a length-to-width ratio of 1.5:1 under normal operating conditions,a four-factor three-level orthogonal test was designed to study the combination of working well wall thickness,bottom plate thickness,internal slab wall thickness and soil stiffness.The load-bearing,deformation law and reinforcement ratio of the structure are analyzed,and the evaluation index of each structural parameter is analyzed,so as to obtain the relationship between each structural parameter and the degree of influence.After analyzing the calculation results,it can be obtained that the thickness of the bottom plate is the most important factor affecting the stress distribution of the working well structure;the stiffness of the surrounding soil mainly affects the maximum vertical displacement of the working well and the stress distribution of the internal slab wall;the thickness of the working well wall mainly affects the work The horizontal displacement of the overall structure of the well and the reinforcement ratio of the structure;From the perspective of reducing the structural reinforcement ratio,the shaft wall thickness should be appropriately increased,and the changes in the other three factors have little effect on the structural reinforcement ratio.Combining multiple factors,considering the stress and deformation of the control structure,the optimal design combination is that the thickness of the bottom plate is 1.3m,the elastic modulus of the soil is strengthened to twice the original,the thickness of the shaft wall is1.0m,and the thickness of the internal slab wall is 0.4m.