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Cast-in-place pile by artificial digging hole with high bearing capacity, quality assurance easy, the advantages of easy construction, has been widely used in high-rise buildings, roads and bridges, deep and offshore oil platforms, and other projects.However, cast-in-place pile by artificial digging hole in the construction can have an accident, usually takes at when a piece of retaining structure located. For example, the dynamic music-quarter is due to the lack of protective wall on the establishment of the theory and experience, leading to the collapse pit, seen personnel casualties. Retaining structure established norms has not had a complete formula, it is usually based on experience, but in the case of thick, waste materials; If located too thin, it prones to accidents, causing casualties and economic losses. Therefore, the study on retaining structure of cast-in-place pile by artificial digging hole has become a pressing issue. This paper is a study on the thickness of retaining structure of cast-in-place pile by artificial digging hole.Based on the clay limit equilibrium conditions , can calculate what deep holes will need to set up retaining structure. Elasto-plastic analysis is being used the oretical pile near the stress concentration, drawn from the pile farther, the smaller the stress concentration, When the pile is drawn from the infinite, stress reduces to the initial stress. The use of elastic-plastic theory of the thin-walled cylinder elastoplastic analysis, as a thin cylinder wall,it is by the surrounding soil, after analysis : retaining structure internal plastic first appeares, as pressure increases plastic zone gradually outward expansion until there appeares lateral wall of plastic, which is the state limit,at this time the retaining structure is the thinnest , in order to allow the project to bias security, the retaining structure should be thicker.As analytical formula for the homogeneous soils derives certain limitations. the paper also uses ANSYS software to support the design of the thickness of the two-dimensional finite element modeling, in the process of simulation of the soil material nonlinearity and the deformation process performance characteristics of the plastic. Specifically, the foundation pit excavation is the erection of retaining structure, as calculated by the 5～6 m need not locate within Lake T, 5～6 m not after digging a section of Meshech Wall, the retaining structure uses the C25 . ANSYS simulation software is used by retaining structure soil to its edge, retaining the stress and displacement situations. By calculating formula overturned and ANSYS simulation, we can arrive at the wall thickness of the reasonable formula. This article based on a study of the theory is credible.
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