| In recent years, many new construction methods and new technology is coming out. Among them, hole pile method construction (hole pile method) is based on the traditional method of shallow excavation and absorb the technological achievements of the cover and cut method. Hole pile method construction is a new construction method which uses a small pilot hole spacing groups, withholding arch, piles, piles and other organic combination of mature technologies. This method achieved remarkable economic and social benefits.But hole pile method construction consist of many process, mechanical conversion process is complex. Currently, deformation and mechanical effects caused by the this method is not enough awareness. The article is based on the construction of SuZhoujie station of Beijing Subway Line 16th. We use the FLAC 3D software to establish the three-dimensional numerical model and discuss the ground deformation law of station when constructing. Meanwhile, we use the ANSYS software to establish the two-dimensional numerical model of station’s main structure. The numerical simulation of the whole construction process reveals the structural mechanics switching mechanism and the structural internal force distribution of the station. The article compares the pilot tunnel and arch monitoring data with numerical simulation results. It provides a reliable data support for the construction of similar projects. The main conclusions are as follows:(1) We establish three-dimensional numerical simulation model of the station and the station for the whole construction process was simulated. And the ground deformation law of station is as follows:The construction of pilot tunnel and arch is the main stage which caused ground deformation. And the ground deformation caused by the construction of pilot tunnel and arch is about 50% and 30% of the final ground deformation. So we can see that the construction of pilot tunnel and arch is the main construction sector to control the ground deformation. The vertical displacement is substantially symmetrical distribution when the station structure is completed and the maximum surface subsidence is 49.3mm in the midline of the station. Horizontal displacement of soil is the both sides soil move to the main axis of symmetry. Generally speaking, the station above ground perturbed more serious, but smaller scope;the closer to the surface disturbance weaker, but the larger scope.(2) We use the ANSYS software to establish the two-dimensional numerical model and simulate the mechanical conversion process of station, the conclusion is as follows:There is a group effect when the pilot hole tunnel construction, and each pilot tunnel excavation on the surrounding rock cave disturbance obviously superimposed effect. Rock around the hole perturbed more serious, the greater the corresponding pilot tunnel early support to withstand internal forces. Before initial support to get rid of the pilot hole, a small pile to withstand internal forces, because the upper load by the early part of the pilot hole branches spread out, then buckle arch support early stress concentration phenomenon exists with the guide hole spandrel connection. After the initial pilot hole support break, buckle arch and column structure and mechanism of the formation of the force transmission pile side, hole pile method construction framework bearing system play a role in the subsequent construction were performed at the carrier system.(3) By analyzing the site monitoring data, we Know the numerical model and calculation parameters are reasonable. The site monitoring data reveals the force variation and deformation low of the pilot holes and the buckle arch support. And the article provides reliable data support and reference for the construction of similar projects. In addition, the measured data are analyzed by deformation of the guide hole buckle arch construction and construction stages of formation were compared,which validate the numerical model and calculation parameters selection is reasonable. |
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