矩形顶管临近地铁施工地表变形特性OACHSSCDCSTPCD

With the utilization and development of urban underground space,the application of rec-tangular pipe jacking project is more and more extensive,in order to investigate the deformation law of the ground surface when the rectangular pipe jacking is constructed in close proximity to the subway tunnels,relying on the pipe jacking project,the whole process of pipe jacking construction is simula-ted by using the software of MIDAS-GTS-NX,and the influence of the change of each construction pa-rameter on the deformation of the ground surface is analyzed.The results show that:(1)In the process of pipe jacking,the soil in front of the cutter plate of pipe jacking machine is extruded to pro-duce uplift deformation,and the surface settlement occurs at the rear due to the loss of strata and un-loading of soil,and the surface uplift deformation at the excavation surface is larger,and the strata is obviously disturbed;(2)Within a certain range,increasing the tunnelling pressure can effectively maintain the stability of the palm surface,reduce surface settlement,and lower the risk of damages to the surrounding buildings and the adjacent underground;(3)Increasing the grouting pressure can control the deformation of the ground surface,and reduce the risk of damages to the surrounding buildings and the adjacent underground.Increasing the grouting pressure can control the soil disturb-ance and reduce the surface settlement,but under the conditions of this project,more than 140 kPa will have an over-compensatory effect instead of increasing the surface settlement;(4)The impact of the friction force on the surface deformation is relatively small compared to that of the trenching and grouting pressures,but the overall settlement of the surface reflects the trend of increasing with the in-crease of friction force.