LI Jiang, LIU Ying, JIA Hongquan, YANG Yusheng

Abstract: For many years, the ultra-deep cutoff wall technology has been the main problem to be overcome in the anti-seepage treatment of dam foundation with deep overburden in Xinjiang, and it has created the best completely closed cutoff wall technology. In order to popularize and apply this technology better, the practice and exploration in this field was summarized, and the achievements of Xinjiang in this field over the years were showed in this paper. The characteristics of the deep overburden of riverbed in Xinjiang and the problems to be solved were analyzed, and the key technologies and innovations in design and construction were summarized by taking the 186m cutoff wall of dam foundation of Daheyan project as an example. The key technologies for the construction of ultra-deep cutoff wall include the design structure of cutoff wall with complex connection forms such as the cancellation of core wall corridor, as well as the complete equipment for pore making and trough formation, mud wall fixation technology, key technology for wall formation, and construction technology for cutoff wall under special circumstances, etc. These technologies had been successfully applied in many projects in Xinjiang, indicating that the construction technology of 200m cutoff wall is mature, which can provide valuable experience for similar projects.

Keywords: deep overburden layer, super deep, concrete cutoff wall, design, construction, key technology