Research on Step Distance Optimization for Rapid Construction of Extra Long Single Line Hard Rock Mass Tunnel
The Qinling Mabai Mountain Tunnel,a special long single track double hole tunnel of the Xi'an-Shiyan High-speed Railway,has a hard rock mass tunnel with granite as the surrounding rock,mainly of Class Ⅱ and Ⅲ rock masses.To meet the requirements of rapid construction of hard rock mass tunnels,determining the reasonable step distance of the arch and secondary lining is a prerequisite for effectively coordinating and organizing various processes.By analyzing the organization design of rapid construction of hard rock tunnels,based on the mechanized configuration of tunnel rapid construction,using FLAC3D finite difference software,a three-dimensional model was established and numerical simulation analysis was carried out.Considering the cross-sectional form,excavation method,and support form of the tunnel,the stability of tunnel surrounding rock and the deformation and stress characteristics of support structures after adjusting the construction step distance are analyzed,and the actual operation equipment configuration and working space requirements of the Mabai Mountain Tunnel construction site were considered.A long-distance step distance that meets the full section excavation and corresponding support conditions was proposed,providing theoretical support for rapid construction of hard rock masses.
single track tunnelhard rock massreasonable step distancenumerical simulation
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