Research on Key Technology for Qingganglin Small Clear Distance Tunnel Construction
This paper is based on the construction engineering of Qingganglin small clear distance tunnel in Sichuan Province.the total length of the left line section of the tunnel is 1 725 m,and the total length of the right line section is 1 729 m.The thickness of the intermediate rock pillar is less than 1 time of the tunnel excavation span,which belongs to small clear distance tunnel.The clearance section size of the tunnel's main hole is 15.25 m×5 m.In order to solve the construction difficulties such as small clear distance tunnel excavation and ensure the construction quality,the small clear distance section of the small clear distance tunnel adopts the combined initial support of steel frame,anchor rod,steel mesh and wet shotcrete,and the φ108 mm large pipe roof+advance ductule advanced support.The tunnel entering is constructed by twin-side heading method,and the tunnel excavation adopts drilling and blasting design.After adopting the above key technologies,the small clear distance tunnel is excavated to the specified depth,and the implementation effect is good,which can be used for reference.
small clear distance tunneladvanced supporttwin-side heading method
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