基于粗糙集与贝叶斯决策的尾矿坝浸润线预警

Saturation Line Pre-warning of Tailings Dam Based on Rough Set and Bayesian Decision

为支持尾矿库的现场安全监管与决策,根据粗糙集和贝叶斯决策理论,提出了基于不确定性的尾矿坝浸润线预警方法以确定合理的尾矿坝浸润线预警阈值。首先,根据尾矿渗透性与干滩长度的不确定性对坝体稳定性的影响,计算得到离散尾矿坝体安全系数对应的浸润线的多点位(埋深)数据;其次,以粗糙集属性重要度分析为前提,采用贝叶斯决策法建立坝体安全系数与浸润线埋深的多属性决策模型,以互信息熵表示安全系数对浸润线多点位埋深数据的依赖程度;最后,用条件概率量化浸润线重要点位对尾矿坝稳定性的影响,通过最大后验概率确定浸润线埋深预警阈值。通过对陕西某尾矿坝的实例研究,得出堆积坝标高1 220. 03、1 200. 03、1 180. 03、1 150. 03 m处的浸润线高于37. 33、19. 9、17. 6、11. 6 m时,尾矿坝存在潜在不稳定风险,应采取措施降低浸润线高度。结果表明,浸润线预警阈值能客观反映尾矿坝稳定性状况,完善了尾矿库的现场监测预警体系。

In order to support the site safety supervision and decision-making of tailings pond, according to the Rough Set attribute and Bayesian Decision theory, an early warning method of tailings dam saturation line based on uncertainty to determine the reasonable warning threshold of tailings dam saturation line was proposed. Firstly,according to the influence of the permeability of tailings and the uncertainty of the length of the dry beach on the stability of the dam, the safety coefficient of the discrete tailings dam corresponds to the multi-point (buried depth) data of the saturation line was received. Secondly, based on the importance analysis of the Rough Set attribute, the Bayesian Decision-making method is used to establish the multi-attribute decision-making model with the safety factor of the tailings dam and the buried depth of the saturation line. The mutual information entropy is used to express the dependence of safety factor on the multi-point buried depth data of the saturation line. Finally, the conditional probability is used to quantify the influence of the important points of the saturation line on the stability of the tailings dam, and the early warning threshold of the buried depth of the saturation line is determined by Maximum Posterior Probability. Through a case study of one tailings dam in Shaanxi, it is concluded that the tailings dam is potentially in instability when the height of the saturation line at the elevation 1 220.03, 1 200.03, 1 180.03 and 1 150.03 m of the embankment is higher than 37.33, 19.9, 17.6,11.6 m. To stabilize the risk,measures should be taken to reduce the height of the saturation line. The research shows that the early warning threshold of the saturation line can objectively reflects the stability condition of the tailings dam and improves the on-site monitoring and early warning system of the tailings pond.