Karst Region Groundwater Catchment Feature In Southwest China And Control Action On Cross-mountain Tunnel

In southwest china where carbonate rocks distribute widely, the tunnel through carbonate rocks all occur karst water and mud bursting different degree. There is close relation between climatic characteristics, formation lithology, geological structure , topography and geomorphology with the problem of engineering geology in tunnel project. Topography and geomorphology are important factors to influent karst development and control tunnel karst water bursting, which control karst groundwater catchment.This thesis taking karst region in southweat china as study object, basing on karst geomorphology shapes and types classification, combining with lots of engineering examples, we research the most five typical karst geomorphology shape'water catchment and drainage in southweat china. and that influences on the situation of karst supplied. Furthermore, combining with tunnel examples, research the topography and geomorphology control on tunnel karst water bursting. The main results are as follows:(1)It divides to types according to collecting form .The compound feature of plus and minus configuration also can divides into enclosed catchment feature,semi-enclosed catchment feature and opening catchment feature detailedly,slope can divides into ravinated slope and integrated slope.(2)It study with the characteristic of water draining and catchment divideing by karst feature type. taking the most typical karst geomorphology shape as emphasis, this thesis analyzes karst groundwater catchment and drainage features about each karst geomorphology shape. Combining with many engineering examples, it is to confirm the value range of precipitation recharge coefficient, and to conclude karst groundwater supplyment, catchment and drainage.the rainfall infiltration factor is above 0.6.However,integrated slope which belongs to opening catchment configuration is the worst, the drainage.the rainfall infiltration factor is below 0.3.(3) Combining with tunnel examples in southwest china, this thesis analyzes topography and geomorphology influent on karst development and control on tunnel karst water bursting. It further concluding topography and geomorphology control on karst groundwater catchment and drainage. It reveal that topography and geomorphology are important factors to influent karst water bursting in tunnel. Finally, it makes some prevented principles and measures for tunnel water bursting.