Research On The Behavior Of Bridge Piles Foundation Subjected To The Lateral Soft Clay Movement Due To Heaped Loads

Soft clay is widely distributed around the rivers, lakes, and oceans and it is required to widen and highten the road subgrade in the connecting segments of road and bridge. When there are large thickness of the soft clay in these regions, the abutment piles would sink and deflection under embankment overburden, resulting rupture of piles and detachment of bridge panel, and even traffic accident. Abutment piles subjected to the lateral soft movement called"passive piles", and the problems of"passive piles"is more complicated than"active piles". Therefore it is necessary to carry on research to the interaction between movement soil and piles, considering key influcing factors as possible and establishing the reasonable analysis models. Research contents in this paper are as follows:Firstly, in order to have a better understanding of abutment piles constructing on soft clay, the current research situation of the behavior of bridge piles foundation subjected to the lateral soft clay movement due to heaped loads is summarized, including: theoretical research, experimental study and FEM.Secondly, some existing methods for computing the ultimate lateral earth pressure of piles are compared, which are applied to design the anti-sliding piles. And then, a method for computing the ultimate lateral earth pressure based on the plastic deformation theory and considering the roughness of the piles is proposed. Compared to some field data, the calculated results of the ultimate lateral earth pressure using the method proposed in this paper are reasonable and can be used to analyze the deformation of the abutment piles in soft ground.Thirdly, based on the lateral earth pressure of piles and using the p-y curves to consider the nonlinear of the interaction between piles and movement soil, this paper put forward a method to calculate the deformation behavior of the abutment pile and the effectiveness of the method is verified through an example. And some significant conclusions are getted in this chapter.And then using finite element software and setting the pile-soil contacting element, the 3-D FEM model of the abutment piles constructed in the soft clay is established. In this model, earth pressure distribution, pile-soil interaction mechanism and the moment of the piles and the influencing factors are discussed.Finally, some measures are put forward to reduce the lateral movement of the abutment constructed in the soft clay.