降雨条件下上游法尾矿坝漫顶溃坝机制及其预测模型研究

Unusual rainfall is the primary cause for the failure of the tailings dams, and the overtopping is the most representative mode for the failure of the tailings dams. As for the mechanism of overtopping under the rainfall conditions, current researchers' knowledge of this important issue is superficial. This project focuses on the key scientific problems in disaster prevention and control of the tailings dams in China, namely "study on the overtopping mechanism of the tailings dams constructed by the upstream method and its prediction model under unusual rainfall". The tailings dams constructed by upstream method is taken as the research object. The indoor experiments, model experiments, theoretical analysis and numerical simulation method is adopted to systematic study this problems in depth. Through the experiments of the unsaturated tailings material, a practical strength model of the unsaturated tailings material is established. The overtopping mechanism of the tailings dams constructed by upstream method is obtained through the overtopping model experiments. Combination with the crested weir relationship, sediment transport formula, collapse extension conditions and tailings slope stability analysis, which uses the practical strength model of the unsaturated tailings material, the prediction model of the overtopping under the condition of rainfall is obtained. The VC++ is used to achieve the model visualization. On this basis, some typical accidents of the tailings dams is analyzed to validate and amend prediction model. This project will overcome the bottleneck of disaster prevention problems of the tailings dams constructed by the upstream method under the overtopping failure conditon, and have a higher theoretical value and good application prospect.

不寻常降雨是尾矿坝溃坝的首要原因，而漫顶溃坝破坏是其中最具代表性的破坏模式，目前研究者对这一重要问题的认识欠深入。本项目针对我国尾矿坝灾害防治中的关键科学问题-降雨条件下上游法尾矿坝漫顶溃坝触发机制及其预测模型，以上游法尾矿坝为研究对象，采用室内实验、模型实验、理论分析与数值模拟相结合的方法进行系统深入地研究。通过室内试验建立非饱和尾矿材料的实用强度模型；进行上游法尾矿坝漫顶溃坝模型实验，揭示了降雨条件下上游法尾矿坝漫顶溃坝机制；结合水动力学堰流公式、泥沙输移方程及其溃口扩展条件，并将非饱和尾矿材料的实用强度模型用于尾矿边坡稳定性分析，得到降雨条件下上游法尾矿坝漫顶溃坝预测模型；运用VC++实现该模型的可视化，采用该模型模拟某一典型尾矿坝的漫顶溃坝事故，验证该模型的正确性。本项目研究将突破上游法尾矿坝灾害防治的瓶颈问题，具有较高的理论价值及良好的推广应用前景。

不寻常降雨是尾矿坝溃坝的首要原因，而漫顶溃坝破坏是其中最具代表性的破坏模式，针对该问题,本项目对此进行深入研究。本项目以上游法尾矿坝为研究对象，采用室内实验、模型实验、理论分析与数值模拟相结合的方法进行系统深入地研究。通过室内试验建立非饱和尾矿材料的实用强度模型；进行上游法尾矿坝漫顶溃坝模型实验，揭示了降雨条件下上游法尾矿坝漫顶溃坝机制；结合水动力学堰流公式、泥沙输移方程及其溃口扩展条件，并将非饱和尾矿材料的实用强度模型用于尾矿边坡稳定性分析，得到降雨条件下上游法尾矿坝漫顶溃坝预测模型。.通过对42起能确定溃坝原因的事故研究表明：引起尾矿坝溃坝因素依次为尾矿坝边坡稳定性不足、违规建设、不寻常降雨；坝高为20～40m的尾矿坝发生溃坝事故的概率较大。分别进行不同干密度尾矿样的脱水试验，测量不同吸力下尾矿样的含水量。在此基础上，整理得到不同干密度下尾矿样的土水特征曲线，得到修正的Gardner模型，Gardner模型的拟合曲线与堆积尾矿的实测土水曲线十分接近，拟合相关性高，修正后的Gardner模型可以很好地描述和预测非饱和尾矿材料的土水特征曲线。针对降雨条件作用下上游法尾矿坝漫顶溃坝进行模型试验，根据试验结果，尾矿坝的溃坝过程可分为了两个阶段，即溃口启动和溃口扩展两个阶段。在此基础上，在假定尾矿坝溃口形状的基础上，分析了尾矿坝块体的受力情况，获得了尾矿坝溃口形成的启动条件，并用模型试验的结果进行验证取得了较好的一致性。接着，阐述溃口扩展速率和溃口展宽的机理，运用泥沙动力学和土力学原理，得到了溃口扩展模型，将得到的扩展模型应用于模型试验，比较了两者的结果。本项目研究可预测上游法尾矿坝漫顶溃坝破坏过程，并可为尾矿坝在其他作用下的溃坝机制提供参考，具有一定的理论价值及应用前景。