Study On The Construction Technology Of Shield Launching Shaft Of Urban Metro In Narrow Field

With the development of the metro construction and the extensive utilization of the shield tunnel technology, researches of the technology of shield launching shaft deep excavation construction of urban metro in narrow field, and according that gives the corresponding optimization recommendations and attention are becoming to be a hot subject. Based on the shield launching shaft deep excavation construction of the first contract section of Guangzhou Metro Line No.2-8, using the 3D-FEM method and analyzing the field monitoring data, the site layout and planning of the shield launching shaft, the track beam of 40t gantry crane which crossing the deep excavation and its support system, shield launching shaft deep excavation construction, and the influence to deep excavation by shield launching were systematically studied in this paper.Main Research Methods and Contents:1. Firstly, the problems and cautions of the site layout and planning of the shield launching shaft were put forward. On this basis, the shield launching shaft and shield construction site were arranged systematic and scientific, and summarizing the layout principles of the metro construction in narrow site. And then, the track beams and its support system of 40t gantry crane were designed by proceeding from actual engineering.2. The track beams of gantry crane and its support, shield launching shaft deep excavation and shield launching of 40t gantry crane were studied by the 3D-FEM. The paper has analyzed the change condition of displacement and stress of surrounding ground, the track beams of gantry crane and its support and the support and structure of shield launching shaft deep excavation.3. Comparative analyzing the Finite element analysis results and on-site monitoring data, and Combining with the actual construction of the scene, the corresponding optimization recommendations and construction measures were proposed to design track beams of gantry crane and its support, support system of shield launching shaft deep excavation and parameters of shield launching.Main research results:1. Analyzed the importance of shield launching shaft site layout and its key processes, and gives the way for using construction site reasonable, in case to make the layout is the most reasonable.2. Designed and analyzed the track beams of gantry crane and its support, and combining with the actual construction of the scene, gives the reasonable way of track beams layout of gantry crane in narrow site.3. Analyzed the change condition of displacement and stress of surrounding ground and support structure in deep excavation of different conditions, and according that gives the corresponding optimization recommendations and attention of deep excavation support structure in the geological characteristics and construction condition.4. Analyzed the influence to deep excavation by shield launching shaft deep excavation, and combining with the actual construction of the scene, the corresponding optimization recommendations and construction measures were proposed to shield launching.