尾矿库坝体溃决演进规律的模型试验研究

本文结合实际工程,在自主研发的尾矿库模型试验平台上完成了尾矿库模型的搭建,进行了由于坝体排渗系统失效致使浸润线持续升高而诱发的尾矿库溃坝模型试验。利用坝体位移跟踪测量系统对尾矿库坝体溃决的演进过程进行了观测,总结了整个试验过程中的溃决模式及破坏形式。结果表明,坝体整体呈逆流牵引型溃决模式,溃决破坏形式大致经历三个阶段:坝面沼泽化诱发张拉裂缝、流土与局部塌落、较大范围崩塌与滑坡,其中前两个阶段是崩塌与滑坡的诱发阶段。在流土破坏出现前会出现堆积坝局部渗水、坝体裂缝等现象,此时若采取有效措施迅速降低浸润线,可避免发生大范围流土破坏。崩塌与滑坡过程溃决量大、持续时间短,一般难以防范。将模型试验结果与数值模拟结果和尾矿库溃坝原型资料对比,三者吻合良好。本文提出的模型试验方法可以预测尾矿库溃坝过程以及对尾矿库溃坝事故进行反演分析。

Experimental model study on dam break and evolution law of tailings pond

According to the practical project, the tailings pond model was set up based on a self-developed dam-break model test system. The dam-break model test was carried out under the continuous rise of saturation line caused by the failure of drainage system in the tailing pond. In the tests, the dam break and evolution process of the tailings pond was observed and measured by the dam displacement measuring device, and the dam-break pattern and dam-failure mechanism were discussed. The results show that the type of dam break belongs to the reversed-stream and traction failure, and the dam break process can be approximately divided into three stages:(1) tension cracks appeared by the dam surface swamping,(2) soil flow failure and local collapse failure, and (3) extensive collapse failure and landslide failure. The first two stages are the induced phases of the collapse and landslide failure. Before soil flow failure the cracks appeared on the surface of the dam and the seepage water overflow from the dam. If the effective measure can be carried out to reduce the saturation line at first time,the extensive soil flow will be avoided. The collapse and landslide failure has the characteristics of larger break body and shorter duration, which is difficult to prevent. Comparison of the model test results with the numerical results and the prototype observed data,it is showed that the model test results are in well agreement with the others. The model test method in this paper could be used to predict and inverse the dam break process of tailings ponds.