| Deformations of soil induced by the excavation will exert additional stress on the pile foundation within its influence range,resulting in lateral deformations or insufficient bearing capacity of the pile,thus adversely affecting the pile,which will cause uneven settlement of the structure(building)in the long run and lead to local damage of the soil below the pile,and even distort the deformation of the upper structure(building),affecting its use safety.This paper deeply analyzes the mechanism of mutual influence between excavation and adjacent pile,establishes the functional relationship between maximum horizontal deflection of pile and system stiffness,and proposes a prediction method of maximum horizontal deflection of pile,which can put forward reasonable reference for similar pile engineering.In this paper,based on the effect of deep excavation on single pile,the response law of pile under different working conditions is studied,the system stiffness under different support schemes is discussed,and the system stiffness is related to the maximum horizontal deflection of pile,and the specific research contents are as follows.(1)The pile deflection under the influence of factors such as horizontal spacing between pile and supporting structure and excavation depth of the pit is analyzed by analyzing the actual measured data of different deep foundation pit engineering.The twostage method is used to analyze the deflection and internal force of pile,and the free deflection field of soil during the excavation is used as the input condition to solve the differential equation of lateral deflection of single pile by introducing the improved modulus of foundation reaction into the Winkler model.(2)A numerical model is established to study the effects of pit on the surrounding soil,supporting structure and adjacent pile,analyze the effects of different factors on the force deformation law of pile,explore the degree of influence of different system stiffness on pile,and relate the system stiffness to the maximum horizontal deflection of pile,and analyze the relationship between them.(3)Study the effect of excavation on group piles,compare the change of deflection trend of single pile and single row pile under the free condition of pile top,analyze the effect of shading and reinforcement between group piles,explore the effect of change of integrated stiffness on the maximum horizontal deflection of group piles,propose the method of predicting the maximum horizontal deflection of pile based on the system stiffness of pit support,combine the change rate of maximum horizontal deflection of single pile and group pile about the system stiffness,introduce the effect of The critical system stiffness that affects the change rate of maximum horizontal deflection of pile foundation is introduced. |
