Study On Coupling Effect Of Large Deep Foundation Pit And Control Of Construction Deformation

With the rapid development of urbanization,gradually increasing the utilization of urban underground space,in the same area a series of specifications of foundation pit and the synchronous construction or in succession construction,which in turn have a different degree of the superposition of coupling of the influence of foundation pit surrounding environment,retaining structure of foundation pit,the pit bottom soil resilience,namely the coupling effect.The influence degree by soil condition,construction sequence,construction conditions and various pit complexity multiple factors,mechanism of the effect of different factors on foundation pit surrounding environment,retaining structure and soil heave and there is no perfect conclusion,especially of Zhengzhou region of silt on the coupled effect of the foundation pit population has not yet been found in the newspapers.Therefore,it is imperative to problem of the coupled effect of the foundation pit population in the silt area in Zhengzhou were in-depth study to guide the engineering practice.Zhengzhou Xinzheng International Airport Phase II construction project mover system engineering adjacent to the under construction of subway foundation pit engineering and become a typical super large and deep foundation pits engineering,in this paper,taking the project as the background,using FLAC3 D finite difference software,using Mohr Coulomb constitutive model and Mohr Coulomb failure criterion,the three-dimensional numerical model is established,of group of coupling effect and construction of super large and deep foundation pit deformation control problem for the research are as follows:(1)Through the establishment of pseudo three-dimensional foundation pit excavation model and combining with theoretical analysis,that single foundation pit excavation surface around the foundation pit settlement,the variation of the deformation of foundation pit and soil heave,and studies the coupling effect mechanism of complex foundation pit and influence analysis of foundation pit stability and security of the main factors.(2)Based on the above-mentioned theory research as the basis,combined with engineering examples,three numerical model is established.Firstly,it analyzes the adopted in the project of construction deformation control measures,and verify the control effect;and then the numerical calculation results and the actual monitoring data comparison analysis to prove the correctness of the numerical simulation results,to ensure that the coupling effect research result is true and reliable.(3)Based on the analysis of different excavation sequence,different construction conditions foundation group surrounding ground settlement,foundation pit row pile deformation,pit bottom soil resilience coupling effect mechanism,and based on this,for similar projects of excavation sequence is proposed,so as to guide the engineering practice.