大型高尾矿坝灾变机制与防控方法

大型高尾矿库隐患治理是"十三五"期间遏制重特大事故的重要任务和重点工程之一。高应力下尾矿材料的细观结构和宏观力学特性演化、大型尾矿坝沉积规律及复杂条件下高尾矿坝的劣化理论是其中的关键问题。为揭示尾矿细观结构特性,对尾矿材料进行了光学显微镜观察、电镜扫描和CT扫描处理,建立了尾矿材料的三维重构模型;为揭示高压下尾矿材料的力学特性,对尾矿进行了高应力三轴试验、高应力渗透固结联合试验,研究了高应力下尾矿材料的强度、渗透和固结特性;为揭示尾矿的沉积特性,进行了尾矿材料的大型模型试验,得到了矿浆流动、淤积形态、尾矿料物理力学性质的空间分布以及夹层结构在空间内的分布规律;为揭示高尾矿坝的失稳机制,通过理论分析与数值模拟,对高压下尾矿的强度准则进行了讨论,高尾矿坝的稳定性分析建议使用强度折减法;为揭示尾矿的排渗设施淤堵机制与服役性能,进行了尾矿-土工布渗透试验以及微观观测,发现细粒尾矿更容易产生物理淤堵,且化学淤堵程度与溶液中离子的种类和浓度有关;为了推进尾矿坝风险管控技术,搭建了尾矿库重大风险评估监测系统平台,以便实现尾矿库基础数据的提取、实时风险预警等智能化功能。通过以上坝体劣化理论研究、溃坝灾害评估与预警,提升了我国大型高尾矿库筑坝与灾害防控水平。

Disaster mechanism and prevention methods of large-scale high tailings dam

The control of hidden hazards of large-scale high tailings ponds is an important task and key project to contain major accidents during the "13 th Five-Year Plan" period. Key issues closely related to this research topic are the evolution of the meso-structure and macro-mechanical properties of tailings materials under high stress, the sedimentary regularity of large tailings dams, and the theory of degradation of high tailings dams under complex conditions. In order to reveal the meso-structure characteristics of the tailings, the tailings materials can be screened by optical microscope, electron microscope scanning, and CT scanning. In this paper, a three-dimensional reconstruction model of the tailings materials is established. In order to reveal the mechanical properties of tailings materials under high pressure, a high-stress triaxial experiment and high-stress conjoined consolidation permeability tests are carried out, and the strength, permeability and consolidation characteristics of the tailings materials under high stress are analyzed. To reveal the sedimentary characteristics, a large-scale model test of tailings materials is carried out. The spatial distribution of the slurry flow, siltation form, the physical and mechanical properties of the tailings, and the spatial distribution of the sandwich structure are obtained. To reveal the failure mechanism of high tailings dams, the strength criteria of tailings under high pressure are discussed through theoretical analysis and numerical models. The strength reduction stability analysis of high tailings dams is recommended. In order to reveal the clogging mechanism and service performance of tailings drainage facilities, tailings-geotextile permeability tests and microscopic observations are carried out. Fine-grained tailings are more prone to physical blockage, and the degree of chemical blockage is related to the type and concentration of solution ions. In order to promote the risk management and control technology of tailings dams, a major risk assessment and monitoring system platform for tailings dams are put forward, which can realize the extraction of basic data of tailings dams, real-time risk warning and other intelligent functions. Through the above-mentioned research activities, the level of dam building, disaster prevention and the control of large-scale high tailings ponds in China have been substantially improved.