川东褶皱带明月峡背斜区地下岩溶发育规律

川东隔挡式褶皱带一直是四川、重庆东西向交通通道的天然屏障,隧道可快速穿越褶皱山区,但其在建设时却常常遭遇岩溶涌突水等地质灾害,威胁着施工人员安全与生态地质环境。通过分析川东明月峡背斜区各类排泄基准面控制的地下水循环模式,研究了明月山及所在的川东地区地下岩溶发育规律及岩溶发育深度。结果表明:川东及明月峡背斜区主要可分为贯穿河谷型、横向深切沟谷型、横向浅切沟谷型3类排泄基准面控制的地下水循环模式;在贯穿河谷控制的地区,岩溶向深发育;横向深切沟谷控制的地带,岩溶也具有一定向深发育的能力,岩溶发育深度一般在沟谷之下200~500 m;横向浅切沟谷密集发育的地带地下岩溶发育深度大致在200 m以内。研究结果对于预测与规避川东地区隧道建设时面临的岩溶涌突水灾害及减小其对地质环境的影响有参考价值。

Development Rules of Underground Karst in the Mingyue Gorge Anticline Area of the Eastern Sichuan Tectonic Belt

The belt of folded strata in east Sichuan has always been a natural barrier for the transportation eastward of Sichuan and Chongqing. Tunnels could pass through the folded mountainous area quickly; but tunnel construction often encounters geological disasters such as karst gushing and water inrush, which threatens the safety of construction workers and ecological geological environment. By analyzing the groundwater circulation patterns controlled by various discharge datum in the anticline area of Mingyue Gorge in east Sichuan, we studied the development rules and depth of underground karst in Mingyue mountain and east Sichuan, and obtained the following conclusions: in east Sichuan and the Mingyue Gorge anticline zone, the groundwater circulation mode can be divided into three patterns according to the discharge datum: penetrative valley, transverse deep valleys, and transverse shallow valleys. In penetrative valley controlled region, karst develops to the deep; in transverse deep valley controlled zone, karst also develops to the deep in the range 200-500 meters below the valley; in transverse shallow valleys, karst develops roughly within 200 m range. The research findings are of referential value to predicting and avoiding karst gushing as well as reducing impact on geological environment.