尾矿库坝基管涌破坏试验

以绵阳市平武县某铅锌矿选矿厂尾矿库设计资料为依托，利用尾矿坝溃坝致灾模拟试验台，对尾矿坝坝基进行了渗流破坏（管涌）的砂槽模型试验；观察并分析了渗流破坏（管涌）发生、发展并导致溃决的过程，即坝基管涌破坏可概化为无明显渗透变形阶段、形成阶段、发展阶段和整体破坏阶段等4个阶段；揭示了渗流破坏（管涌）的演化机理：当坝基水平平均水力梯度低于临界水力梯度时，管涌沟槽向上游仅在坝基一定范围内发展并最终停止，一旦超过该临界值后，管涌沟槽持续发展并最终与上游连通，连通管流的强力冲刷最终导致坝基整体结构失效和溃决。试验结果表明：①尾矿库坝基管涌破坏仅发生在砂层顶部的浅层区域；②坝基管涌破坏的水平平均临界水力梯度为0.484。

Ping Damage Expriment in Dam Foundation of Tailing Reservoir

Based on design data of a Pingwu tailing reservoir of lead-zinc concentrator in Mianyang city，a series of flume model experiments were conducted to study seepage damage (piping) of tailing dam foundation by simulation experiment platform of tailing dam-break.The whole development process from seepage damage (piping) incipit to dam failure was observed and analyzed，and it means that piping damage of tailing dam foundation can be generalized into four stages:no seepage deformation stage，forming stage，development stage and overall damage stage.Evolution mechanism of seepage damage (piping) was revealed:piping channel towards the upstream develops only within a certain area and eventually stops when horizontal average hydraulic gradient is under critical hydraulic gradient.Piping channel will persistently propagate towards the upstream and finally cause dam foundation structure to fail or break as the horizontal average gradient exceeds the critical value.The experiment result showed that piping damage of tailing dam foundation only occurs in shallow area at the top of tailings; Horizontal average critical hydraulic gradient of piping damage is 0.484.