Abstract: According to various excavation depth and the formation conditions, a database of 80 engineering case histories on the urban rail transit foundation pit in Beijing is analyzed, and the ground deformation due to the foundation pit excavation in Beijing sand & gravel zone and clay soil zone is studied. The results show that 1) The distribution of the maximum ground displacement approximately follows a normal distribution or half normal distribution form. 2) The average value of maximum ground settlement is 0.11%H in sand & gravel zone and 0.20%H in clay soil zone, where H is the excavation depth. 3) The ground deformation is related to the pile horizontal displacement on or out of the pit. 4) When the insertion ratio increases, the ground settlement decreases. The system stiffness exerts significant influence on the ground settlement in clay soil zone. 5) The main influence zone around foundation pit is 0.6H or 0.7H. The results can be used to calculate the lateral deformation of similar projects in Beijing and other areas, helping guide the related engineering design and construction.

Key words: urban rail transit, foundation pit engineering, ground deformation characteristic