Research on the temporary support method of shield expansion excavation construction of metros passing through ground crack sections
To investigate the influence of different temporary support methods on surrounding rock deformation during shield expansion excavation through ground fissures,this article focuses on the construction of the section between Fujunmiaocun station and Zhucun station of Xi'an metro line 15.FLAC3D and Midas GTS NX software are utilized to analyze the surrounding rock deformation and the shield tunnel force during the shield expansion excavation process and when excavating through ground cracks.These are also used to come up with a reasonable temporary support method for practical applications and to compare the deformation situation with that of the field ground surface.The research results illustrate that the double vertical temporary support has a good controlling effect on the surrounding rock deformation and tunnel structure.The breaking and trenching construction of the first ring tube sheet changes the integrity of the tunnel structure,which leads to a drastic increase of surrounding rock deformation,thus making it a dangerous part of the shield expansion excavation construction process,which needs to be paid attention to.Through on-site monitoring,ground subsidence during excavation construction remains within permissible limits,with the impact range of excavation construction mainly within a 7-ring radius.Advanced reinforcement measures can be implemented in conjunction with the excavation impact range during construction projects.
metroshield expansion excavationtemporary supportsurrounding rock deformationon-site monitoring
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