Study On Horizontal Displacement Of Bridge Pier And Abutment In Deep Silt Stratification Areas

For building bridge in deep silt stratification areas, due to the silt have the characteristics of high moisture content, high compressibility, low permeability and high sensitivity, so the subgrade is worse stability. In bridge construction and application periods, the dead loading of that bridge embankments often cause the silt soil layer's lateral displacements and adjacent pile foundations' horizontal displacements. It'll to the failure of the bridge structures and traffic accidents.the analytic methods about question mentioned above are less and so much idealization, the experiment studies consume more times and energy and have some randomicity. Therefore, the numerical methods are one of fundamentality approachs to solve a good many complex factors above for the analytic and theory level of passive piles-soil interaction. It see little of the FEM methods to analyse bridge filling-passive piles-soil interaction in deep silt stratification areas. In this paper, although it is pilot attempt to study the lateral transformation mechanics of bridge Pier and abutment piles in deep silt stratification areas, that is signality for the optimum design of bridge pier and abutment piles in practice engineering.therefore, To solve this problem, the behavior of bridge pier and abutmentagainst soil lateral movements in deep silt stratification areas has been studied, The main contents and conclusions can be given as follows:Firstly, based on the synthetize analysis of engineering disease in domestic and overseas, the basic reasons and transformation mechanics of bridge pier and abutment in deep silt stratification are analyzed detailedly. Then it is systematic summary of existing field tests, model tests and analytical approaches of passive piles, to summarize the trend in development of passive piles.Secondly, based on considering the affects of the soil arching on bridge Pier and abutment piles, the 2D Finite element model is set up to analyse the soil arching effects around the passvie piles about some kinds of influencing factors, for example the soil property, piles spacing and multi row piles and so on, to optimum design inpractice engineering.Then, 3D Finite element method is used to simulate the behaviour of passive piles-soil interaction with plastic flow of silt, with a view to the various influencing factors such as embankment load, silt stratification thickness, pile condition and so on, and to analyse the horizontal mechanics of multi row passive piles.Finally, the resolve measures of bridge embankment filling effects on the Pier and abutment piles are expatiated, such as reducing the density of bridge embankment filling and improving bridge piles structure. Through the theory analysis and numerical calculate of the resolve measures with Finite element model, some availability conclusions for improving bridge embankment filling effects on the Pier and abutment piles are also taken.