某高寒、高海拔高铁隧道洞口段下沉整治技术

Techniques for Sinking Remediation of a High-Cold,High-Altitude High-Speed Rail Tunnel Opening Section

某高铁隧道地处祁连山中高山区,洞口海拔3000 m以上。线路开通运营后,隧道出口段多年冻土地层发生缓慢融沉,隧道洞口段仰拱填充面、道床板出现横向裂缝,相邻路基段路肩塌陷下沉、路肩封闭层下和桩板结构板下脱空,轨道出现不均匀沉降、平面偏移。对隧道洞口段采取隧底注浆加固、无砟轨道抬升纠偏及相邻路基段路肩下沉、桩板结构板下脱空进行换(回)填处理后,线下基础稳定,线路运行平稳。

A high-speed rail tunnel is situated in the mid-high Qilian Mountains,with its entrance at an altitude of over 3000 meters.Over the years of operation,the permafrost at the tunnel exit section has gradually thawed and subsided.This geological change has resulted in transverse cracks appearing in the invert filling surface and track bed slab at the tunnel entrance section,as well as shoulder collapse and subsidence in the adjacent embankment section.Additionally,voids have developed under the shoulder sealing layer and the slab structure of the pile cap.These issues have ultimately caused uneven settlement and lateral displacement of the track.To address these challenges,targeted engineering measures are proposed in this paper.Initially,grouting reinforcement was applied to the invert of the tunnel entrance section to enhance geological stability.Subsequently,corrective measures were implemented on the ballastless track to elevate and realign it,addressing the lateral displacement caused by settlement.Meanwhile,efforts were made to backfill the collapsed shoulders of adjacent embankment sections and fill the voids under the pile cap structure boards,restoring their original load-bearing capacity and stability.Following the implementation of these construction measures,the foundation beneath the rail line has been restored to a stable state,allowing for smooth resumption of track operations.