Study On The Calculation Design Of Method And The Application Of Secant Pile Wall In The Support Structure Of Metro Station

Since the 80's in the last century, the exploitation and utilization of underground space has attracted more and more attentions. The development of underground engineering causes deep and large pit,which becomes inevitable trend. A safe, economical and reasonable support method of deep pit becomes a hot pot at present. Secant pile wall is a new kind of foundation pit support, whose theoretical research and design method is not analysed and summarized comprehensively.The paper adopts the methods of theory analysis, numerical simulation and site monitoring to research. Considering the comparability among secant pile wall, colonnade retaining wall and diaphragm wall, a design method of secant pile wall equivalent to rigidity distribution method of diaphragm wall is given. The internal force of the surrounding protection structure has been calculated using equivalent beam method,and comparied with the numerical computation result for the confirmation design method accuracy. Combining secant pile verticality and theory of cavity expansion, the calculation method of secant degree and secant time is given. Then the length,engagement of pile,the ratio of rigidity for two kind of pile and so on the factors to the designing of the secant pile wall had been analyzed with numerical computation. Background of Binhe Road Station in Hangzhou Metro Line 1 and based on the method of finite difference numerical simulation, variation regularity of displacement and bend moment of secant pile wall in different construction phases is studied. Base on the analysis of site monitoring data, variation regularity of displacement in different construction phases is given, variation regularity of support axial force is analysed for representational section.Rigidity distribution method of secant pile wall and the calculation method of secant degree and secant time in this paper provide reference for similar foundation pit engineering. The analysis of site monitoring data has positive meaning to study structure stress distortion regularity. Construction technics, construction measures and disposal method of familiar accident pile provide reference for similar project. The researching of each kind of influence factors,the rule of displacement and the bending moment of the secant pile wall under the different construction stage as well as the scene measured data's analysis has the positive sense to the rule research of the secant pile wall structure's stress and distortion.