Dissertation
Dissertation > Industrial Technology > Building Science > Construction > The project and the type of work > Foundation engineering

Research on deformation characteristics to optimize the design and construction process of excavation program by

Author HeChen
Tutor ChenJianHong
School Central South University
Course Underground Space Science and Engineering
Keywords Pit Plaxis Finite element method Numerical simulation F-spw
CLC TU753
Type Master's thesis
Year 2011
Downloads 282
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With Chinese rapid economic growth, the pace of urban construction and reconstruction is also faster and faster. Therefore, the design of deep foundation become increasingly important. Expansion of urban’s function and large urban population make modern city crowd. At present, ground space has tended to become saturated, and there is a growing emphasis on the development and construction of underground space, resulting in a large number of foundation pit.Pit excavation, because of long time, high costs and many difficulties in design and calculation, is a focus for civil engineers how to reasonably calculate, design and check the braced system. This article takes the Nanjing Renheng G53 pit engineering as the background, by the application analytic hierarchy process principle, Hierarchical complex pit supports and protections plan decision-making question. According to the pit supports and protections system’s characteristic establishment hierarchical structure model, people select the most superior supports and protections plan. In the excavation process, Plaxis, a Finite element method software, was used in this paper to simulate the engineering. Excavation and shoring were analyzed by this software. Harding-soil model was used in this paper to simulate the soil. Then set different project step to simulate the excavation and shoring process. Structural internal force, displacement and the earth’s surface sedimentation can be calculated by this way. We can get many conclusion as follows.1、According to the basic principles of AHP, pit program was established comprehensive evaluation index system, and identify 4 evaluation indicators and calculations by the analytic hierarchy index weight. Gravity retaining wall of deep mixing piles was chosed as Sealing curtain and bored was in.2、The design theory of Pit-retaining Structure has been studied by the numbers.The soil Pressure theory actuality and the application and development of the finite element in the foundation Pit have been analyzed. At the same time, the mechanics properties of the deep foundation pit and the calculation theory of soil pressure and water pressure, have been researched. 3、Initial stresses and displacements before excavation are investigated by finite element method through expatiating the finite element theories and methods during the processing of deep foundation excavations.4、PLAXIS, an huge geotechnical engineering finite element program, has been introduced. Combined with Practical measurement of engineering, factors of design、construction and natural environment on effect of deformation of retaining structure are studied by PLAXIS finite element program. The important factors are analyzed by quantification, and deformation of timbering structures infoundation Pit excavation and the developing and changing rules of the settlement of surrounding stratum have been founded out. Some measurements, which offer reference to design and construction of deep foundation pit, to control deformation of foundation pit have been forward.5、In this paper, excavation process is calculated and analyzed by survey and design software "F-spw", which validates the correctness of the new-built mode land the Properness of adopted parameters.

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