Experimental Study on the Flatness of Concrete for Initial Support of Railway Tunnels
Taking the Taipengshan Tunnel of Chengdu-Dazhou-Wanzhou High-speed Railway as an example,this paper carries out experimental research on the flatness of shotcrete for initial support,and draws the following conclusions:(1)When the working wind pressure of the side wall is 0.4 MPa and the spraying distance is 1.5 m,the rebound rate is the lowest,and the flatness is the highest.(2)When the working wind pressure of the arch is 0.4 MPa and the spray distance is 1.5 m,the rebound rate is the lowest,and the flatness is the highest when the working wind pressure of the side wall is 0.4 MPa and the spray distance is 1.8 m.(3)The flatness of the arch is lower than the flatness of the side wall.(4)The optimal parameters of the side wall are the jet wind pressure of 0.35-0.4 MPa and the spraying distance of 1.2-1.5 m,and the rebound rate and flatness match are the highest.(5)The optimal parameters of the arch are the jet wind pressure of 0.4-0.45 MPa and the spraying distance of 1.5-1.8 m,and the rebound rate and flatness match are the highest.(6)It is recommended to use up and down and reciprocating types for the spray route.(7)The new process of"211"shotcrete summarized makes the surface flatness of concrete better and more beautiful.
tunnel initial supportflatnessinjection pressureinjection distancejet routes"211"jetting process
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