Design optimization and application of bolt-shotcrete support for East Tianshan tunnel project in China
November 17-20, 2019
Bolt-shotcrete support is a form of support with low cost, convenient for construction, uniform structural stress, which is widely used in international tunnel engineering. In this paper, the 2# inclined shaft of East Tianshan tunnel in China is taken as the research object. The stress characteristics of composite lining support and bolt-shotcrete support are analyzed and compared by FLAC3D software, and the bolt-shotcrete support scheme suitable for this project is put forward. Based on the principle of orthogonal experiment, the most reasonable shotcrete material proportion is selected, and structural stress and displacement monitoring is carried out during the construction stage of typical sections. The results show that: (1) in FLAC3D simulation calculation, the interface element is applied between different layers, which can simulate the interaction between different layers of lining structure and reflect the mechanical characteristics and displacement characteristics of the interface between layers; (2) from the aspect of mechanical performance, single layer lining which can meet the requirements of tunnel support with thinner structural thickness and has higher economic efficiency, is better than composite lining; (3) the field monitoring results show that the deformation of bolt-shotcrete support structure is small, the structural stress meets the material performance requirements, and there is no structural damage during the construction of the test section; (4) during the implementation of bolt-shotcrete support, the cost of support per meter is reduced by 36.78%, and the average excavation efficiency is increased by 38.9%, which verifies the applicability and advantages of the optimization scheme. The research results in this paper can provide reference for the follow-up construction of tunnels and similar projects.
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Junsheng Yang and Li Linyi, "Design optimization and application of bolt-shotcrete support for East Tianshan tunnel project in China" in "Shotcrete for Underground Support XIV", Matthias Beisler, ILF Consulting Engineers Asia, Ltd., Thailand Preedee Ngamsantikul, Thailand Underground and Tunneling Group (TUTG), Thailand Herbert Klapperich, TU Freiberg, Germany Eds, ECI Symposium Series, (2019). https://dc.engconfintl.org/shotcrete_xiv/16