Abstract: 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.

Key words: karst development rules, underground karst, Mingyue Gorge anticline, East Sichuan tectonic belt, tunnel engineering