In The Inner Supporting Retaining Structure With Waist Beam Around The Force Analysis And Optimization Design

With China's rapid economic development, urban land increasingly nervous, top or tall building fit more and more peripheral environment restrict the more strict, so more and more is also high to the requirement of deep foundation pit. Foundation pit supporting and earth excavation is often encountered in traditional civil engineering project, it is a complex technology, fusion theory, experience, and risk in the integration of design and construction technology. With the deepening of the foundation pit supporting research and foundation pit supporting design practice often appear too aggressive or too conservative phenomenon,optimization design of supporting structure has become the focus on professional and technical personnel and discussed topic.In view of the present within the support beam waist in the design of supporting structure design is not comprehensive consideration of supporting pile(wall) stiffness contribution,resulting in excessive waist beam reinforcement is too large or section of the phenomenon,this paper use the concrete design principle of "beam slab structure" waist beam calculation model is set up, with supporting pile(wall) and waist beam bending stiffness ratio as waistbeam of variable parameter analysis, analysis of the supporting pile(wall) stiffness on the stress of the beam waist. Combining the author's team engineering(guang hong building foundation pit supporting) case waist beam reinforcement calculation are expounded, and with the large general 3 d finite element analysis software Midas- GEN the actual model calculation result is compared, confirmed the supporting pile(wall) of the waist beam having the role of the load. According to the different thickness of underground continuous wall and the combination of waist beam section size relations, analysis in different combinations in proportion to the total load low back beam. The main research contents and research results are as follows :(1) According to the design principle of the concrete beam slab structure ", " supporting pile(wall) generalized simulation into board structure, waist beam simulation Cheng Liang structure, waist beam analysis model is established. Bending stiffness ratio as variable parameters, analysis of different thickness of supporting pile(wall) effect on the internal force distribution of the beam waist, it is concluded that the thicker the retaining pile(wall), the share of the conclusion of the greater the proportion of soil pressure.(2)With the examples of hong building foundation pit supporting project by comparing does not consider the calculation method of underground continuous wall stiffness and consider the calculation method of underground continuous wall stiffness, prove the existence of underground continuous wall of waist beam to share the role of the earth pressure and other load. As according to the consideration of the underground continuous wall stiffness calculation results, it is concluded that after optimization of the cross section and reinforcement scheme.(3) Through the large general 3 d finite element analysis software Midas- GEN set up different thickness of underground continuous wall and waist beam section size combination model, analysis the waist beam under the different combination of internal force, it is concluded that the waist beam under different combination of the size of the proportion of total load.