Study On The Construction Mechanics Behavior Of Puhuangyu Metro Station

In a complex urban environment, where open-cut method and top-down method can not be employed during metro station construction, Cavern-pile method is widely applied because of its advantages of high security, small impact on the surrounding environment. In the progress of the cavern-pile method construction, mechanical switches frequently and the behavior of construction mechanics is complex. So, it is necessary to study on construction mechanical behavior of metro station which is built by cavern-pile method. At the same time, in the construction of metro lines, the satuation where a tunnel crossing a existing station is unavoidable. As a consequence, it is necessary to study on the construction mechanical behavior of tunnel which is built under the existing subway station.This paper is based on Puhuangyu subway stations of Bei Jing Subway Line14, taking the new subway stations built by cavern-pile method and the subway tunnel crossing the existing station as research objects. Three-dimensional numerical simulation and similar model experiment for the subway stations built by cavern-pile method, three-dimensional numerical simulation for the subway tunnel crossing the existing are launched, the main research work is as follows:1.The ground settlement, the stratum displacement, and the variation of the structural internal force of subway station in the construction process of subway station built by cavern-pile method under4rock conditions and4construction schemes are researched by employing finite difference software. The study obtains the dynamic characteristics of the mechanical behavior during the excavation process of the station, revealing the location of the maximum internal force of structure and the corresponding process during the excavation.2. The ground settlement, the stratum displacement, and the variation of part of the structural internal force of subway station in the construction process of subway station built by cavern-pile method under2rock conditions and4construction schemes are researched by employing similar model experiment. Model experiment results and numerical simulation results are basically identical.3. The whole construction process constructed by CRD method and bench method of tunnel crossing the exiting station are simulated by finite difference software, mechanics behavior of the two methods are gotten. This paper analyzes the difference of the stratum displacement, the structural deformation and internal force of the new undercrossing tunnel. The displacement and stress of the existing station between the two construction methods, reveales the advantages and disadvantages of the two methods.