淤泥冲击挤压作用下软基土石坝动力响应分析

以江西城门山铜矿城门湖区软基土石坝为研究对象，基于淤泥流动过程中的冲击力特性，采用FLAC3D程序模拟和分析了淤泥冲击挤压作用下软基土石坝的水平速率、水平位移和剪应变等动态响应。研究结果表明：（1）坝体速率变化规律与冲击挤压作用周期基本一致。坝体监测点速率大小及发生运动的区域均随时间增加而增大。约在0.3 s（1/2周期）时，速率达到最大值；而约在0.45 s（3/4周期）时，发生运动的区域达到最大；之后随着冲击荷载的衰减坝体质点逐渐趋于静止。（2）淤泥冲击挤压作用下坝体发生了永久位移，平均位移值约30 mm，可看作坝身整体向下游侧移动了30 mm。（3）坝体内形成了一条明显的剪应变增量贯通带，发生区域位于上层软土坝基内，表明坝体最可能沿此位置发生整体滑动失稳破坏。

Dynamic response analysis of soft foundation earth-rock dam under impact and squeezing action of silt

The soft foundation earth-rock dam in the Chengmen lake in Chengmenshan copper mine of Jiangxi province was selected as a case study. Based on the characteristics of impact force during the silt flowing process, FLAC3D program was used to simulate and analyze the dynamic response of earth-rock dam, such as the horizontal velocity, displacement and shear strain, under the impact-squeezing action of silt. The research results are drawn as follows: (1) The variation law of the dam velocity is basically identical with the period of the impact-squeezing action. The monitoring point velocity and motion region in dam increase with the time. The monitoring point velocity reaches the maximum at about 0.3 s (1/2 period); while the motion region reaches the maximum at about 0.45 s (3/4 period). Afterwards, the dam tends to be static with the attenuation of the impact force. (2) Permanent displacement happens in the dam under the impact-squeezing action of silt. The average displacement is 30 mm, which can be seen that the whole dam moves 30 mm towards the downstream. (3) An obvious coalescence zone of shear strain increment generated in the dam is located in the upper soft foundation of the dam, which indicates that the dam will probably slide and damage along this coalescence zone.