Study On The Construction Technology Of Subway Shield Tunnel Under Crossing Pedestrian Passage

Recently,the exploration and utilization of underground space have aroused extensively attention.Rock engineering varies with different geological conditions in cities nationwide.During the construction of shield tunnel,different geotechnical engineering problems will be also encountered.The influence of the construction under cities with soft soil foundation for the surrounding buildings is the key factor that affects the designation and construction.In some soft soil foundation cities,building subsidence and damage for the public facility caused by the shield construction have attracted more attention.Based on the city of Xiamen island to the Xiangan sea channel project Wuyuan Bay station and Exhibition Center station to tunnel through the pedestrian tunnel engineering,research status review of shield tunneling theory of earth pressure balance shield are discussed,and the numerical model of EPB shield tunneling under construction process line the channel using the finite element software ANSYS.The research of tunnel in different depth and stratum changes,the excavation method of right hole,the first excavation of the right tunnel after excavation of the left tunnel and the right tunnel excavation and excavation of the left tunnel excavation after wearing walkway excavation influence of pedestrian and displacement the surface subsidence,the results were as follows:(1)When the buried depth of the tunnel is more than 2.6 times,the Y direction displacement of the pedestrian passage shows the "seesaw" effect when the tunnel section is not at the same time.When the depth of the tunnel is less than 2.6 times,the seesaw effect disappears.(2)No matter whether the excavation of the right hole after the excavation of the left hole or the excavation of the right hole after the excavation of the right hole will affect the X and Z direction displacement of the pedestrian passageway.(3)With the increase of the buried depth of the tunnel,the Y direction displacement of the pedestrian passages increases sharply.After the excavation of the right tunnel,the maximum displacement of the left hole excavation method is the largest,and the excavation method at the left and right sides is the smallest.(4)With the increase of tunnel burial depth,the Y direction displacements of pedestrian passages are decreasing,and the displacement produced by the first right rear left excavation method is larger.(5)When the left and right holes are excavated separately,the slope of the surface subsidence change above each other is basically the same,that is,when the left hole is excavated first,the surface subsidence above the left hole and the change rate of the surface subsidence above the left hole when the right is excavated first.(6)When the level of the surrounding rock of the tunnel varies from V to IV,whether the right hole is excavated after the first excavation of the left hole or the first excavation of the left hole after the excavation of the right hole,the displacement of the Y direction of the pedestrian passage is reduced by about 25%,the difference in the displacement of the X and Z is not significant,and the slope of the surface subsidence is reduced by about 70%.