Study On Lateral Deformation Of Piled For Bridge Abutments Under Embankment Overburden On Soft Ground

With the rapid economic development of our country, the expressway construction has entered an unprecedented phase of rapid development. Our country has vast territory, natural and geographical environment is different, especially soft clay is widely distributed around the rivers, lakes and oceans. It is required to widen and heighten the road subgrade in the connecting segmens of road and bridge. When there are large thickness of the soft soil in those regions, the abutment pile would sink and deflection under embankment overburden, and this can cause vehicle skip, rupture of pile and detachment of bridge panel, and even bring traffic accident. Abutment pile loaded by lateral soil movement called "passive pile". As the lateral earth pressure of passive pile due to soil movement is difficult to determine, the problems of "passive piles" is much more complicated than "active pile". Therefore, study on passive piles have significant theoretical and practical values.Firstly, in order to better understanding of passive pile, the difference between the passive pile and active pile is introduced, then generalize the present research condition of passive pile, including: theoretical research, experimental study and FEM.Secandly, several issues of displacement-based methods are discussed, including pile-soil relative displacement, non-linear load transfer model, modulus of subgrade reaction and free displacement field of soil under embankment, facilitate describing relevant content in later chapters. And then special research of the lateral ultimate earth pressure of pile is made. ultimate pile lateral earth pressure is divided into active and passive earth pressure respectively, analyse the piles in cohesive soil, sandy soil and pile group from active and passive parts. Based on Guo's (2001) closed-form solution, the ultimate earth pressure of active part in Ningbo region is determined using two test piles data. Using ABAQUS finite element software the ultimate earth pressure of passive part is studied.Thirdly, based on the passive pile and soil interaction, the passive pile was divided into passive part and active part in the computation model, p-d curve and p-y curve were adopted in the passive part and active part respectively, and ideal elastic-plastic model was applied in p-d and p-y curves, the matrix of soil-displacement factors and Pasternak model were used to consider the interrelation of soil springs, and bending moment and deformation of passive pile was solved by the displacement compatibility differential equation obtained from finite difference method. Based on the analysis of single pile, the pile row with bent taking into account the factors of bent and pile - soil - pile interaction is researched.Finally, above method was used to calculate the engineering cases. On the emergence of the problem, and introduce the corresponding reinforcement measures. A static load test is applied to examine the effect of reinforcing, and monitoring data show that the lateral displacement of abutment piles have been effectively controlled, which illustrate that reinforcement was successful.