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Analysis of Water Seepage Characteristics and Formation Mechanisms
in Seasonal Water-Rich Tunnels in a Karst Area of Chongqing
(Key Laboratory of Transportation Tunnel Engineering, Ministry of Education; School of Civil Engineering, Southwest Jiaotong University, Chengdu 610031)
Abstract Based on an investigation of 66 of the 187 operational highway tunnels with water seepage in Chongqing, this paper selects 15 tunnels with serious water seepage for a statistical analysis and indicates a connection of water seepage to karst landforms and seasonal rainfall according to its distribution characteristics. Using the Xiushan tunnel as an example, the paper discusses water seepage characteristics and relevant formation mechanisms. The results shows that: (1) water seepage in tunnels in the Chongqing karst area typically has the characteristics of zonal distribution, temporal continuance, dynamic karst water changes, unfavorable geological conditions, and an intermittent connection between water surrounding the tunnel and the underground river; (2) passing through a developed karst area, three working conditions may be encountered by tunnel construction at different stages, i.e., a normal condition, high water-pressure condition, and low water-pressure condition; and (3) water seepage is a result of multiple factors, especially the hydrogeologic conditions, design factors, construction quality of the waterproofing and drainage facilities, failures during operation, etc. The practice indicates that tunnels in these geological conditions should follow the principle of drainage first with blocking to follow.
Abstract：
Based on an investigation of 66 of the 187 operational highway tunnels with water seepage in Chongqing, this paper selects 15 tunnels with serious water seepage for a statistical analysis and indicates a connection of water seepage to karst landforms and seasonal rainfall according to its distribution characteristics. Using the Xiushan tunnel as an example, the paper discusses water seepage characteristics and relevant formation mechanisms. The results shows that: (1) water seepage in tunnels in the Chongqing karst area typically has the characteristics of zonal distribution, temporal continuance, dynamic karst water changes, unfavorable geological conditions, and an intermittent connection between water surrounding the tunnel and the underground river; (2) passing through a developed karst area, three working conditions may be encountered by tunnel construction at different stages, i.e., a normal condition, high water-pressure condition, and low water-pressure condition; and (3) water seepage is a result of multiple factors, especially the hydrogeologic conditions, design factors, construction quality of the waterproofing and drainage facilities, failures during operation, etc. The practice indicates that tunnels in these geological conditions should follow the principle of drainage first with blocking to follow.
ZOU Yu-Lin,
He,
CHUAN etc
.Analysis of Water Seepage Characteristics and Formation Mechanisms
in Seasonal Water-Rich Tunnels in a Karst Area of Chongqing
[J] MODERN TUNNELLING TECHNOLOGY, 2014,V51(4): 18-27
2014, Vol. 51 