Research On The Influence Of Side-Crossing Of Subway Earth Pressure Balance Shield Construction On Adjacent Twin Buildings

At present shield construction is the most widely used method in subway and tunnel excavation,for soft soil,it has unique advantage methods for crossing buildings.However,the construction of subway shield tunnels is carried out in the stratum,In the process of shield machine driving,it will inevitably affect the adjacent soil layer,resulting in deformation of buildings above the soil layer and causing safety accidents.At the same time,most of the subway shield construction need to pass through the buildings.This article considers the building,soil layer and shield machine as an organic whole,analyzes the mechanism of the disturbance of the surrounding soil layer during the construction of the shield tunnel.The disturbance reasons about the adjacent soil.The interaction about between the buildings and the stratum between the buildings when the side of the shield tunnel was installed.Finite element numerical simulation is a practical and effective method in the field of geotechnical engineering to analyze the deformation of surrounding environment caused by shield tunnel construction.This article collates the previous research in this arera,at the same time the excavation mechanism of the tunnel is further deduced.The twin similar adjacent apartment buildings are used as the engineering background in the shield section of the East Extension Line of Tianjin Metro Line 1.The finite element software Midas/GTS is used to fully consider the nonlinearity of soil material,the action of shield machine on stratum,the action between stratum and segment,the pressure of grouting outside segment,the loss of formation and the pressure of tunneling(earth pressure),etc.in a 3-D finite element model.The dynamic simulation of tunneling process of shield tunneling is carried out,and the deformation law of adjacent soil layer in the excavation process of shield machine is obtained.The trend of the deformation results is fitted well with the measured value.The interaction between adjacent apartment buildings is analyzed when the shield tunnel side crossed in the tunnel-soil-structure finite element model.The relationship between adajiacent buildings at different locations during the construction of the shield tunnel is considered.It is found that the ratio of the net distance between the twin buildings to the depth of the tunnel axis has obvious influence on values of the settlememt,the loacal tilt and the tosion in the proceding building.When the ratio is about equal to 1.0,all of the values are achieving their minum values.The safety and stability of the buildings during the process are evaluated.For this reason,similar projects can be used for reference.