Research On Mechanical Behavior Of Utility Tunnel Gallery In Xi’an Ground Fissure Area

At present,China is in the process of rapid urbanization,and the infrastructure construction in major cities is also advancing at the same time.As the lifeline project of the city,the underground pipe gallery structure is being vigorously promoted under the government’s advocacy.In Xi’an area,because of the unique geological structure characteristic of Xi’an ground crack,the construction of the underground comprehensive pipe gallery in the main urban area has encountered a difficult problem.According to the existing literature,the distribution of ground fissures in Xi’an,including the plane distribution,profile distribution and structural characteristics of the Xi’an ground cracks,is discussed in accordance with the current situation of the Xi’an ground fissure and the current construction of the underground tube Gallery,and the deformation characteristics of the Xi’an ground cracks are analyzed,including the formation of the distribution of the Xi’an ground cracks.The three dimensional destructiveness of the activity of the ground crack and the progressive characteristic of the ground crack activity,the possible damage to the main structure of the underground pipe gallery in Xi’an,the concrete damage forms,and the possible engineering problems such as the leakage of the corridor,the settlement of the soil and the deformation and damage of the pavement,are also discussed.Combined with the actual engineering pipe gallery traversing the ground fissure problem,ABAQUS finite element software is used to establish the corresponding calculation model,and the numerical simulation analysis is carried out.The structure calculation hypothesis,the model simplification condition,the pipe soil interaction model,the load and the structure boundary condition of the tube gallery are discussed,and the constitutive relation of the soil material and the stress and strain curve of the reinforcement and the concrete material and the element selection of the calculation model and the meshing method are discussed.Combined with the stress and displacement response of various components of soil and pipe gallery,the static behavior of underground pipe gallery is studied.By adjusting the intersection angle of the ground crack and the tube Gallery,the section length of the gallery and the value of the soil parameters,the effect of the ground crack on the tube corridor is analyzed.It is found that the closer the intersection angle is 90 degrees,the smaller the section length of the tube corridor is,the more the soil surrounding the soil is,the smaller the damage of the structure is.Considering the activity of ground fissure,the representative soil pipe gallery model is selected to calculate the dynamic response of various components of soil pipe gallery under earthquake.Based on the displacement and acceleration responses of some grid nodes of the soil tube structure,the dynamic behavior of the underground pipe corridor is studied by comparing the time history response and the peak acceleration.It is found that the acceleration response of the grid nodes near the ground cracks is obviously higher than that of the other grid nodes.The deformation will accumulate and increase gradually.The influence of waveform,seismic wave peak value and the direction of seismic wave exerted on the simulation results is analyzed.It is concluded that the amplitude of the earthquake has great influence on the dynamic response of the tube soil model,and the influence of the azimuth influence of the waveform and the seismic wave is small.