The Finite Element Analysis Of Inverse Construction Method Extra Deep Foundation Pit Support System

With the development of city construction, there are more and more deep foundation pit projects,thedepth of which is increasing.Many high buildings constructions among the intensive building complex.because of narrow construction field, the deep excavation work without any protection can't be implemented.Neighboring building that must be protected require strictly stability and deformation control of supportstructure for deep excavation pit. Set the finite element model of diaphragm wall and other structures in deepexcavation with finite element software, simulation of deep excavation pit and the whole process of theexcavation and supporting is analyzed in this paper.Analysis internal forces and deformation and groundsettlement of each condition. The following conclusions have been achieved by means of simulationcalculation.1.Two dimensional finite element method adoped in this paper can actually simulate the influence of theprocess of excavating,unloading of soil mass,Installation of supporting.And indicated that this method is ofhigh practicability and validity.2.The result of calculation tested that the design combinationed of main body with strutting system caneffectively control the deformation of deep foundation pit. It is proved by calculation and measurement thatadopt beam and slab structure as horizontal supporting forming great rigidity,it produce small deformationof diaphragm wall and little influences of the ambience out of the excavation of deep foundation pits.3. Measured data and calculated results show that the maximum horizontal displacement occurs on the lowerthan middle of excavation depth,which is different from deformation of conventional construction ofdiaphragm wall(The maximum horizontal displacement occurs on the bottom of excavation and horizontaldisplacement decreases along the depth) .4. Adopting advanced Hardening Soil Model. Because unloading property is specially considered inHardening Soil Model, Hardening Soil Model has better rigidity compared to MOHR-COULOMBModel,which has only one rigidity parameter.Actually,unloading modulus is larger than deformation modulus.a better result of simulated results could be obtained by adopting Hardening Soil Model.