Research On Deformation Of Foundation Pit Under Traffic Load

With the rapid development of urban rail transit,and the pits of subway stations can be seen everywhere,there are many factors affecting the stability and safety of the foundation pit in the subway station,but at present,scholars mainly focus on the ground water,soil reinforcement,construction method,supporting structure forms,etc,and the influence of traffic load on the deformation of foundation pit has not been thoroughly explored.In the current study,the traffic load is generally considered as a uniform static load,but the actual traffic load is a kind of random variable load,this simplified method is extremely unfavorable to the design of the foundation pit and the safety of the foundation pit.In this paper,the influence of traffic load on the deformation behavior of foundation pit is analyzed based on an example of a subway pit excavation project in soft soil area,four aspects are mainly studied as follows:Firstly,based on the actual situation of on-site road traffic,the deformation characteristics of the foundation pit on the south(near road side)and north side are analyzed according to the actual measurement of the project;secondly,The finite element analysis results are compared with the engineering measurement,and the rationality of the finite element model of Abaqus is validated;thirdly,considering the current dynamic load simplified model is difficult to consider the actual distribution of vehicles,the deformation characteristics of the foundation pit are analyzed using the quasi static model of the single axis concentrated load from the vehicle layout,the vehicle layout is determined by the following three factors: vehicle distance,distance of road from foundation pit,and the number of lanes,the law of pit deformation characteristics caused by the vehicle layout is obtained;finally,according to the half wave sinusoidal dynamic load model,the deformation characteristics of the foundation pit under different speed and axle weight are analyzed,and the general law influenced by the variation of speed and axle weight is obtained.