Studies On The Performance Of Soil Foundation Reinforced By Geogrids With Model Test And FEA

The soil is mixture of disseminated values, water and gas. It has lowly resist-pull intensity. The reinforced foundation is a new kind of structure, which is added with geosynthetics as reinforcement material at the appropriate position in soil. If the reinforcement works effectively, it can greatly improve the bearing capacity and stability of the foundation. As one of the new geosynthetics, geogrids are chosen because of its high strength, low elongation and high stability.Based on the studies of predecessors, the paper is combined with Da Yao gulf 250 thousands tonnage special ore dock engineering. The model test, which can reflect the deformation characteristic of real structure under static step loads, is performed in a room, and the geogrid and filling soil are same to field condition. The capability of the reinforced foundation with different parameters also be researched. Further more, its nonlinear behavior under excitation was analyzed by Finite Element Analysis program. Finally, some beneficial conclusions are found and some suggestions are put forward. The main work are as follows:(1) Look back generally to elaborate the history and development of the reinforced soil structure, and the research situation in the fields of theoretic, model tests, and numerical analysis at present. And the characters of geogrid and the reinforced soil also be introduced.(2) Design an indoor reinforcement foundation model test. Compare the reinforced foundation characteristic with the unreinfoced one under static loads. Change three parameters, which are the number of geogrid layers N , the length of the geogrid layer b, and the distance between the bottom of the foundation and the top geogrid layer u, to research the influence of them under the condition of loads. And advise an optimal reinforcement project for strip shallow foundation.(3) Analyze the results of the model test, and comment the merit and defect of the current reinforcement theory and their applicability in detail. Furthermore, the action between geogrid and filling soil and the perfect action mechanism also be discussed. It would be beneficial to the furthermore study.(4) Basted on the studies of theoretics and model test, the model was simulated by FEM software ANSYS. The calculate results indicate that reinforcement by geogrid make the vertical stress distribution more average and the horizontal stress, shear stress decrease. Finally, compare with the model test results, the simulated analysis results are in good agreement with them.