Analysis of effect on adjacent metro tunnels due to foundation pit excavation in soft ground

Based on one engineering practice of deep pit construction in soft ground,the application of finite element method to simulate the construction process of deep foundation pit is presented.The deformation of foundation pit and the excavation affection on metro tunnels are analyzed in detail with the results of different FEM models being compared and some conclusions drawn.Due to consideration of underground water and time-space effect,HSS model is more suitable for modeling pit construction than HS model.In order to control the effect on metro tunnel caused by pit construction,such measures as block excavation,dewatering should be taken.The process of concrete diaphragm wall trenching cannot be modeled,therefore,the deformation of surrounding soil and adjacent tunnel should be controlled during the construction process.The experience and conclusions presented can be referred in the design,construction and site monitoring of similar tunnels.