尾矿坝垮塌机制与溃决模式试验研究

基于云南拉拉铜矿小打鹅尾矿库工程设计资料，采用现场排放尾矿砂为试验材料，进行了尾矿堆积坝在洪水情况下发生垮塌破坏的模型试验。通过水流控制系统模拟尾矿坝遭遇洪水情况，采用侧面示踪点、水位测压管、应力传感器以及数码摄像机等设备获得了尾矿坝溃决过程中坝坡的位移矢量演化、浸润线与应力的变化特性以及坝体破坏发展过程，揭示了洪水作用下尾矿坝的垮塌机制和溃决模式。试验结果发现：尾矿堆积坝的浸润线变化存在滞后性；在洪水入库致库区最高设计洪水水位过程中，靠近坝坡中部处水平方向的总应力增量较垂向总应力增量大，增大的水平应力是坝体产生破坏的重要因素之一；洪水导致坝坡尾矿砂所受的渗透力、上浮力、重力以及孔隙水压力增大，削弱了坝体材料的黏聚力，并加大了自身荷载，降低了坝体的稳定性；尾矿坝溃决模式一般为逆流渐进型，破坏先是从坡脚处发生，继而向上游发展，呈现牵引式发展，破坏的滑动面由多个弧形滑移面构成。研究成果加深了对尾矿堆积坝垮塌机制和溃决模式的认识，并在洪水灾害的预防和控制方面作了一些新的探索

Model experimental study of collapse mechanism and broken mode of tailings dam

Based on the physical model experiment and the design data of Xiaoda?e tailings impoundment, the course of tailings dam gravitational collapse in flood was modeled with the field tailings. The water system is controlled to model the tailings impoundment to suffer the flood situation, through the technique of side displacement points, water level measurement pipes, stress transducers and digital photography measurement, a series of important test data are obtained; such as displacements, saturation line, stresses and the broken processes, The mechanism and mode of tailings dam failure in flood are explored. The results indicate that: (1) the character of saturation line change has a time lag of the water level of tailings impoundment; (2) in the processes of the flood into tailings impoundment to the maximum water level of tailings impoundment design data in flood, the horizontal stress increment is larger than that of vertical beside dam slope center, and it is one of the important cause of dam failure; (3) the seepage force, buoyant force, gravity and pore pressure are increased by flood; then the cohesion of tailings dam is weakened and the load of dam is augment; then the stability of tailings dam is reduced; (4) the broken mode of tailings dam performs progressive failure; the failure of tailings dam happened in the toe of the dam and evolved from toe to upstream; it is shown pull-typed behavior, the failure slippage faces are composed of multi-arc faces. The model experiment results can provide significant data for deep study the mechanism of collapse and broken mode of such tailings dam in flood, so as to provide useful information for the prevention and control measures in flood disaster.