| Earth berms are sometimes efficient to reduce the displacment and internal force of retaining structure, and it isn seldom used in our country. Compared with other supporting systems, the use of earth berm when excavation can save a lot of money spending on retaining structure, it can also save the time needed to construct the struct. Earth berm supporting system is employed in excavation of pit in Tianjin Xiangyu Plaza construction engineering which has a large excavation area and a limited time for construction. By construction monitor in excavation, the displacement of the retaining structure and the settlement of the earth surface are obtained, this insures the safety of the excavation construction and we can use the datum to analyse the effect of earth berm.In this paper, the FEM software Plaxis is used to analyse the effect of earth berm on retaining structure using plane strain assumption, and the hardenging-soil model is employed for the costitutive relationship of soil, and an interaction surface is set between the soil and retaining structure. In this paper, the relationship between the displacement of the retaining structure and the length of the top of earth berm, the grade of earth berm and the height of earth berm are analysed. The definition of reaction coefficient of soil is propose based on the Winkler premise, and the simplified analysis method is proposed taking into account the assumption of"m"method, and an elastic reaction program is made based on the simplified analysis method, the relationship between the displacement of retaining structure and the length of the top of earth berm, the grade of earth berm and the height of earth berm is analysed using the program. It can be seen from the datum obtained using the simplified analysis method and the case history that the method is efficient. |
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