玉京山隧道巨型溶洞地质特征与稳定性评价

Geological Characteristics and Stability Evaluation of Giant Karst Cave Affecting Yujingshan Tunnel

成贵高速铁路玉京山隧道施工中遭遇高速铁路建设史上的最大溶洞,溶洞下部发育大型暗河,洞内充填物厚度大,成分复杂,工程地质环境复杂,处理难度大、施工安全危险性高。现场采用地质调查及测绘、三维激光扫描、水文观测、物探、钻探、孔内测试、取样试验等综合勘察手段,查明了巨型溶洞的形态特征、水文地质特征和充填物工程地质特征,对洞壁稳定性进行了分析和评价,预测了洞顶塌落高度及稳定性,提出了“暗河改道、溶洞回填、桥梁跨越”总体处理措施建议,为合理确定施工整治方案提供了详实的地质依据。研究成果可为山区高速铁路岩溶勘察提供重要参考。

During the construction of the Yujingshan Tunnel of Chengdu-Guiyang High-speed Railway,the largest karst cave in the history of high-speed railway construction was encountered,where the geological environment is complicated,with large underground rivers developed underneath and thick filling materials of complex composition inside.The treatment is difficult,and the construction safety risk is high.Comprehensive investigation methods including geological survey and mapping,3D laser scanning,hydrological observation,geophysical prospecting,drilling,in-hole testing,and sampling tests were applied on-site to find out the morphological characteristics,hydrogeological characteristics,and geological characteristics of fillings in this giant karst cave,analyze and evaluate the stability of cave walls,and predict the collapsed height and stability of the roof.The overall treatment measure of“ diverting underground rivers,backfilling karst cave,and crossing with bridges ”was put forward,which provided a detailed geological basis for reasonably determining the construction treatment scheme.The research results can provide an important reference for investigating the karsts of high-speed railways in mountainous areas.