Effect Of Excavation Of Subway Foundation Pit On Vicinity Pile Foundation

The influence of subway foundation pit excavation on the adjacent pile foundation of the bridge is mainly manifested in the displacement of the soil outside the pit caused by the excavation of the foundation pit,which causes additional displacement and bending moment to the bridge pile foundation.Bridge pile foundation will be damaged when the additional displacement and bending moment accumulate to a certain extent.And cause the instability and damage of the bridge.The foundation's holding characteristics are poor in soft soil areas such as Tianjin.The underground structures are more prone to be damaged when an earthquake occurred.Therefore,this paper discuss the influence of foundation pit excavation on pile foundation of nearby bridge both on displacement,internal force and seismic performance of pile foundation.Studies the influence of the excavation of subway station foundation pit on nearby bridge pile foundation.Take the Xueyuanbeilu Station engineering of Tianjin metro line 11 as the research object,built a two-dimensional finite element model.Analyze the influence of the pedestrian bridge pile foundation on the displacements and internal force when a metro station pit is excavation and construction nearby.Discuss the influence on displacement and internal force of the bridge pile foundation when the site soil layer parameters(modulus of elasticity,poisson's ratio,severity,cohesion,internal friction angle),the pile physical parameters(modulus of elasticity),the size of pile(length,diameter)are changed.Verifies the conservation law of inner convex foundation pit.The law is: the surrounding area of horizontal displacement of the wall along the depth direction,the surrounding area of surface settlement around the foundation pi,the surrounding area of swell curve of the foundation pit are approximately equal.At last,the paper take the Xueyuanbeilu Station engineering as the study object,establishing seismic model of finite element.Discuss the influence of the establishment of a subway station on the seismic performance of the nearby bridge pile foundation.And discuss the influence of pile's seismic performance when pile's physical properties(modulus of elasticity)are different.All the data in this paper are from the actual measurement of the Xueyuanbeilu Station project.The calculation results can be used as a reference for the special risk design and the earthquake-resistant design of the subway station.And provide a basis for the construction of the Xueyuanbeilu Station project...