Karst features of the Lianhuatai hydropower station and engineering significance

The Lianhuatai hydropower station is located in the main valley section of the Danjiang river in Shangnan county, Shaanxi Province. Based on geological survey and exploration data, this paper presents the pattern, scale and distribution of the karst in the area of the dam and summarizes the development characteristics of the karst. The results show that karst development in the dam area is mainly controlled by lithology and geological structures. The karst is widely developed and concentrated at some places, characterized by vertical zoning and uneven spatial distribution. The influence of karst on construction mainly includes two aspects， karst seepage and karst stability, the former of which may cause the power station to fail to reach the designed normal water level. The karst caves may lower the anti-sliding stability of dam foundation. Therefore, it is suggested to set up anti-seepage curtains, and to replace and reinforce the karst caves exposed by dam foundation excavation with consolidation grouting. The influence of karst on the project can be effectively avoided with engineering treatment.