三峡一期围堰安全运行3年后拆除。堰体大量采用当地风化砂，其中70m以下为水下抛填，最大抛填深度25m。对部分风化砂进行了调查和物理、力学性能试验，证明水下抛填不会产生大的颗粒级配分离现象，干密度可满足设计要求，堰基淤砂层不会产生振动液化。柔性材料防渗墙运用3年后，墙厚及力学性能均满足设计要求。 The Three Gorges a cofferdam safe operation three years after the demolition. Weirs used a large number of local weathered sand, of which 70m below the water throwing and filling, the maximum throwing depth of 25m. Part of the weathered sand was investigated and the physical and mechanical properties tests were carried out. It is proved that the underwater throwing and filling can not produce the separation of large particles, the dry density can meet the design requirements, and the weir silt layer will not vibrate and liquefy. 3 years after the application of flexible material cutoff wall, wall thickness and mechanical properties meet the design requirements.