Numerical Analysis Of The Properties Of Pile-Net Composite Foundation On Wide Deep Soft Soil In Chaoshan Station

Pile-net composite foundation is a method to improve the behavior of deep soft soil, and has been used broadly in highway embankment, railway embankment, and industral and civil construction recently.In this paper, based on the wide deep soft soil treatment project of the ChaoShan railway station area, statistical analysis and numerical simulation were used to study the engineering properties of soft soil, the deformation rules of non-supporting model, the action mechanism and deformation rules of the pile-net composite foundation, and so on. The main contents and results are as follows:(1) The previous methods dealing with pile-net composite foundation are outlined. The composition and mechanism of the pile-net composite foundation are summed up.(2) Base on the analysis of the physical and mechanical parameters of the ChaoShan deep soft soil, the following characteristics have been found:high water content, high void ratio, and high compressiblity, as well as low intensity, low permeability and low bearing capacity.(3) According to the characteristics of the embankment section DK205+870 of Chaoshan station, the pile-net composite foundation settlement rules and load transfer law of different models were studied using the numerical simulation software FLAC3D. It is concluded that:â‘ the settlement of foundation distributes in bubble shape, and increases with the filling height increasing. The maximum settlement occurs at the center of the roadbed surface, and the maximum lateral displacement occurs at the place which is 10m lower than the toe.â‘¡The influence depth of axial force, skin friction, and negative skin friction increase with the pile spacing increasing. The influence of pile cap to axial force and skin friction is limited, presenting the law that, more than a certain depth, whether there is pile cap, the model curves will coincide. Reducing pile spacing and setting pile cap can reduce the settlement of soil among pile foundation.(4) Finally, the design methods for pile-net composite foundation are summed up.