贵广铁路大源隧道古岩溶坍塌分析

贵广铁路大源隧道穿过古岩溶坍塌堆积区长度达300余米。由于岩溶坍塌现象较为隐蔽,勘察阶段未能有效查清。施工开挖后,根据揭示情况完成隧道围岩级别变更,加强了洞周支护及衬砌措施。在补充基底勘察后,分析了岩溶坍塌判断依据、形成过程,并评价堆积物的稳定性。结果表明:大源隧道工程所穿越的大型古老岩溶坍塌堆积物整体是稳定的,但是,对于局部地段存在的空隙,应采取注浆加固处理。

Analysis on Collapse of Ancient Karst at Dayuan Tunnel on Guiyang-Guangzhou Railway

The Dayuan Tunnel on Guiyang-Guangzhou Railway passes through the accumulation zone of collapsed ancient karst by more than 300 meters. As the phenomenon of karst collapse is relatively concealed, it was failed to be identified in the stage of investigation; then the classification of rock surrounding the tunnel was changed according to the disclosure after excavation with the measures of supporting and lining around strengthened. With the base survey added, the criterion to judge karst collapse and its formation course were studied and the stability of accumulation was evaluated. The results show that the large accumulation of collapsed ancient karst, through which the Dayuan Tunnel passes, is stable as a whole; however, the gaps existing in local sections should be reinforced by grouting.