Numerical Study On The Behavior Of Multi-propped Deep Foundation Excavation

With the development of our country, the process of urbanization is faster and faster, the problem of the rare of land source is standing out day by day. As the exploitation of underground space and the high-rise structures in urban, a large number of deep foundation excavations have appeared lately. Their scale and depth increase constantly. Urban deep foundation excavations are generally surrounded with dense buildings. So their working space is very narrow, especially when close to the adjacent buildings or structures, which made the design and construction more difficult by using the routine design theory and construction technology. Many scholars and engineers have already made great effort in the displacement-controlling design of deep foundation excavations recent years, however, problems remains to be solved in correlation among the deformation of the retaining structures, soil deformation and the displacements of adjacent structures.In this paper, the construction process of the deep foundation excavation is simulated and analyzed using the special geotechnical software FLAC. With numerical simulation, many factors, including the diameter and the space of the soldier piles, the cross-section of the bracing beams, the number of the support layers and the excavating depth in each step, which may affect the behaviors of the retaining structures and deformation of the structures and surrounding soils, were studied. By the simulation, the displacement laws between the soldier piles and the subway tunnel are got, and also the relationship between the maximum displacement of the soldier pile and the maximum settlement around the foundation. Eventually, the author made a suggestion that use two layers of supports, which will make the construction more easily and economically.