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| Research on the Deformation Laws of Center Pillar of Metro Station Excavated by Semi- covered Method |
| REN Jian-xi, MA Ji-nan, BAI Jin-long, YANG Ke, FAN Di, HUANG Jian-bin |
| (Xi’an University of Science and Technology, Xi’an, Shaanxi 710054, China) |
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Abstract Abstract：Research purposes： The center pillar is regarded as a particular support structure for the foundation pit of metro station using semi-covered excavation method, which can directly affect the safe construction, the deformation law of which is sophisticated, about which there are little experience and knowledge especially in loess area. This paper takes the foundation pit of metro station excavated firstly by semi-covered method in Xi'an as study background, studies deformation mechanism and deformation law of center pillar, so as to provide reference for the design of foundation pit retaining structure in the loess area on this condition. Research conclusions： (1) The deformation of center pillar is relevant with the following factors, foundation pit precipitation, vehicle loading, weight of cover plate and support structure and heave of the bottom soil, in which the last factor has the greatest influence on deformation of center pillar. (2) The accumulative deformation of center pillar in real-time can be divided into four phases with little dropping phase, continuous phase, dropping phase and stable phase where the maximum occurs in the second stage. (3) The value of uplift of center pillar is increased with the addition of excavation depth. Therefore, the design must consider uplift problem of center pillar, to ensure that has a sufficient length. (4) The use of temporary pavement system composed of reinforced concrete support and pavement slab and the implementation of the eight steps of the construction process can make the deformation of center pillar safe. (5)The construction method of this metro station and various design parameters of support structure can provide reference to similar projects in loess area.
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Received: 09 June 2017
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2017, Vol. 34 
