The Interaction Of Support Pile-Soil Under Vehicle Moving Loads In Deep Foundation Pit

The study of the effect of vehicle moving loads on pile-soil interaction is still in the stage of start and the research of the interacting situation between soldier pile and soil in deep foundation pit under the nearby vehicle moving loads is still in the blank. This article researches the mechanical behavior of vehicle loads, soil, and pile-soil interface and uses ANSYS software to simulate the interaction of single cantilever pile-soil in deep foundation pit under vehicle moving loads. The main work is as follow:The identification of vehicle model and loading mode:this article identifies the contact track shape and its calculation formula of vehicle tire and road surface through analyzing the characteristics of vehicle loads and discussing various vehicle dynamic models with different degree of freedom, meanwhile, selects double degree of freedom and quarter vehicle model which performs well in the analysis of vertical vibration as the final vehicle model to simulate. Comprehensively considering various influencing factors, this article also proposes the mathematical expression of vehicle loads and finally uses four of the same mobile half sine wave rectangular uniformly distributed loads to describe the four tires of vehicle.The selection of soil constitutive model:according to the analysis of the characteristics of soil material, this article particularly reviews the soil constitutive models under numerical analysis to describe the interaction between soil and structure. And finally on the basis of the nonlinear characteristic of soil material and relative merits of different soil constitutive models, this article selects the currently effective nonlinear elasticity-ideal plastic soil constitutive model--Drucker-Prager Model as the soil material model using in the simulation of ANSYS.The definition of contact surface elements of structure and soil:this article first discusses the theoretical basis and applicability of no thickness contact surface elements and thickness contact surface elements through summarizing the characteristics of the interaction between structure and soil and the development of the numerical simulation of contact surfaces of pile-soil, and then chooses the "generalized" no thickness Goodman contact surface element which performs well in simulation as the final contact surface element using in ANSYS, meanwhile analyzes the normal relationship and tangential relationship between two contact surface elements and points out that the key for choosing proper contact surface elements is to realize contact coordination condition.The analysis results of ANSYS simulation:This article uses ANSYS to simulate the interaction of single cantilever retaining pile-soil under vehicle moving loads in deep foundation pit and comparative analyzes the effect of vehicle moving loads before and after the excavation, the speed of vehicle and the angular frequency of vehicle vibration after the excavation. The results show that:after the excavation, the effect of vehicle moving loads is more obvious than the situation before the excavation; the effect of vehicle moving loads on the settlement is greater than the effect on displacement to the foundation pit which is greater than the displacement along the vehicle driving direction; the disturbance of vehicle moving loads is more obvious in the displacement along vehicle driving direction than in the displacement to the foundation pit and the disturbance to the settlement is the weakest.