The Analysis Of Mechanical Characters Of Composite Ground Under Flexible Foundation

With the development of highway , many different ground treatment technique have been applied in the highway project. Especially various piles-soil composite foundation techniques are extensively applied in the soft soil consolidation and the ground treatment of the highway section where the highway and bridge or thoroughfare join. However , because the rigidity of the embankment is small in the highway , the piles can stab to the embankment and the mechanics under the flexible foundation is different to the rigid foundation in archetectual engineering. At present , there have been some relatively perfect theories and methods for the performance analysis of composite foundation under rigid foundation, while those for the performance analysis of composite foundation under the flexible foundation as the embankment of highway are still not perfect. The research on composite foundation under the flexible foundation still uses the theoretical hypothesis under the rigid foundation, which bring some problems in the practical application and the theory research.Based on the ADINA software, this paper generates 2-D mathematical single-pile model to analyze the the bearing behavior of the composite foundation such as the stress ratio, the friction of pile , and the influential factors of them, such as the pile parameters , the mattress layer parameters , the foundation parameters etc .Through the numerical simulation , this paper summarizes the regularity of the mechanics character. Based on the static balance among the pile and soil, the basic differential equations of the displacements of the pile and soil were deduced. Considering the compatibility condition of stress and strain , based on the vertical deformation of pile and pile-surrounding soil, the analytical formulas calculating the pile friction were drew. For verifying feasibility of the method, the results are contrast with the FEM by way of calculating example, and also carrying on the model experiment. All results indicate: The result derived from this method is compared with that of practical data to vertify its correctness.