Influence Of Underground Pipe Gallery Construction On Surface Subsidence And Adjacent Buildings

In recent years,with the development of underground space,many cities have begun to build underground pipe galleries in the whole country.Among the numerous methods of underground pipe gallery construction,shield tunnel construction is not affected by the ground traffic,does not disturb the surrounding environment,and the construction is concealed well.At present,the application of shield tunnel construction in tunnel and urban subway construction has been researched widely,but there are' few researches on the application of shield tunnel construction in underground pipe gallery construction,and the theoretical researches on the influence of underground pipe gallery construction on surface subsidence and adjacent buildings are not mature yet.Aiming at the problem of how to predict the influence of underground pipe gallery construction on surface subsidence,based on the Peck formula in this paper,the maximum likelihood estimation method is introduced to fit the measured datas considering the heteroscedasticity existed in the previous use of the least square method fitting the measured datas,then surface subsidence is predicted.According to the Peck formula,the maximum likelihood estimation method is used to fit the measured data,the fitting effect is evaluated,the fitting parameters are tested and the settlement through width coefficient K and the ground loss rate ? influencing the prediction of surface subsidence are obtained.Combined with the practical engineering,surface subsidence caused by different embedment depths of the underground pipe gallery is predicted,which provides theory evidence for predicting surface subsidence caused by underground pipe gallery construction.Aiming at the problem of using the modified stiffness method to analyze the influence of underground pipe tunnel construction on adjacent buildings,based on the settlement through width coefficient K and the ground loss rate ? fitted by above-mentioned the maximum likelihood estimation method in this paper,and then the settlement through width coefficient Ks and the ground loss rate VlS considering buildings are calculated.According to the formula of vertical displacement on the bottom of the building calculated by the modified stiffness method,and combined with plane strain principle the formula of horizontal displacement on the bottom of the building is deduced,then the coupling calculation formula of vertical and horizontal displacements on the bottom of the building is obtained along the direction of underground pipe gallery excavation.The vertical and horizontal displacements on the bottom of the building calculated by the coupling calculation formula are exerted on the bottom of the finite element model of the building in the form of displacement loads,which provides theory evidence for analyzing influence of underground pipe gallery construction on internal force and deformation of adjacent buildings.Based on the excavation radius,grouting pressure,excavation footage and actual engineering geological parameter of underground pipe gallery construction,three-dimensional finite element model of pipe gallery-soil-building is established by software ANSYS.The general rules of twist deformation and tilt of buildings and surface subsidence are obtained by analyzing different embedment depths of the pipe gallery,different eccentricities of the pipe gallery and the building and different angles of the pipe gallery and the building,which provides theory evidence for researching the influence of underground pipe gallery construction on surface subsidence and adjacent buildings.