Abstract: Aiming at the construction of cut-off walls in special formations such as the existing overhead leaky formations and loose backfills, based on previous construction experience of cut-off walls, it has been found that such formations are often prone to collapse accidents. In severe cases, the bottom of the drilling platform may even collapse,leading to the drilling The collapse accident caused serious economic losses. Based on this, this article combines the construction technology used in the construction of the anti-seepage wall of the Shuangjiangkou Hydropower Station for similar special formations, and summarizes a set of advanced construction techniques and treatment methods for this type of special formations, in order to provide references for related projects.