Research On Mould Grouting Technology For Vault Of High-speed Railway Tunnel Lining

With the rapid development of high-speed railways,there have been many railway tunnels that have cracks,shedding,knocking cavitation,water leakage,water inflow and other defects in the arches,which seriously threaten the safety of high-speed trains.In the static acceptance of some lines,the railway opening was severely delayed due to quality problems of tunnels,which caused a serious impact on operations and safety,and caused huge economic losses.During the concreting process of High-speed rail tunnel dome lining,the tunnel lining voidsare universally existed behind lining,because of the self defects of pouring process,poor pouring conditions,poor quality consciousness of the pouring staff and loose quality control of construction organization,,.The phenomenon of “two skins” also often appears by the conventional grouting method.Therefore,the structural integrity is poor,which makes the tunnel structure in extremely dangerousstatus.Compared with ordinary railway tunnels,high-speed railway tunnels have the characteristics of large tunnel section,many long tunnels and complex geological conditions,which bring great challenges to the grouting process.In addition,the high-speed railway train runs at a high speed,and once diseases occur in the tunnel,it will be a huge potential safety hazard.At the same time,once the high-speed railway has a safety accident,it often becomes the focus of public opinion and has far-reaching social impact.Therefore,the hazards of lining quality problems of high-speed railway tunnels are especially obviousIn order to solve the problem of the emptying behind tunnel lining vaults,the “two-layer skin” phenomenon of conventional backfill grouting,andin timerepairing ofthe cold joints and the circumferential construction joints at arch linings,as well as remdies of insufficient lining thickness for various reasons.This paper starts with the problems existing in lining voids with conventional grouting,and takes the research on the vertical grouting technology with the tunnel lining trolley at the entrance section of the Lijiadian tunnel of the seventh tenders in Jingshenjing Passenger Railway.The vault mold grouting process has been comprehensively researched and analyzed in timely grouting,grouting design for rigs,embedded grouting pipes,grouting materials,construction equipment,quality and safety control.The final grouting process with mold grouting in the first 1-2 hours after the completion of concrete pouring,withthe RPC embedded grouting pipe into the high-mobility microexpansive early-age retardant mortar as a grouting material,can better solve the traditional disadvantages of the “two skins” of slurry and second-lined concrete,improve the overall bearing capacity of the lining and integrity of lining structure.Therefore,it can comprehensively reduce the risk of cracking,voiding and shedding of lining concrete,and enhance the safety of high-speed railway trains.