Study On Optimizing Mechanical Properties And Construction Schemes For Dome Structure Of Exceptionally Large Scale Underground Railway Station

ABSTRACT:The new Beijing-Zhangjiakou intercity railway station was built in the underground Badaling scenic mountain, as high-speed railway stations, this project is extremely rare among the country and even the world. The design highlights of whole station is the innovative by using a large-span roof dome structure as a station roof, adds a beautiful angle elements to this station in architecture, and fit to the overall image of Badaling; however, that is also a new challenge to aspect of design structure and construction. And the difficulty of construction will be greatly increased because of the rare span of more than40meters of rock used in underground stations dome structures.This paper will use the new Beijing-Zhangjiakou intercity railway station Badaling underground excavation as engineering background, and research the dome structure for large span underground excavation program conduct, by using Midas/GTS finite element analysis software to analog computation it, and draw some basis and rules could be reference during the construction.. The major works are as follows:(1)Reviewing similar projects of the current domestic and international profiles and some basic construction methods of water conservancy and hydropower project construction dome structure, which providing references for selecting a construction programs for new Beijing-Zhangjiakou intercity railway station concourse level ridge eight dome;(2) Provided two kinds of large-span dome structure excavation scheme-the surface guide hole method and the side guide hole method\, and numerical simulation, analyses indexes of surface subsidence, cavern surrounding displacement, plastic zone to produce the range, supporting structure by force displacement, and then get rules during excavation process separately; By using the surface guide hole method during construction, the biggest settlement of surface would be2.08mm, and by using the side guide hole method, the biggest settlement of surface would be1.82mm;the biggest settlement of wall rock would be8.04mm by using the surface guide hole method, and that would be11.15mm by using the side guide hole method.(3)Compare to the indexes among arrangements had been proposed, and finally find out the side guide hole would be relatively optimal choice for construction, and put a further analyze for this scheme.The above finding have engineering guidance for proposed underground station Badaling large span dome structure, and also has certain instructive effect on similar rational design of underground structures to provide guidance.