铁矿尾矿料力学特性及坝体变形稳定性研究

尾矿料矿物成分复杂,物理力学特性区域差异性大。本文以西南地区某铁矿拟建尾矿库为研究对象,对粗、细两种尾矿料进行了系统的物理力学特性试验,获得了粗细尾矿料物理力学指标并应用到尾矿库坝数值分析,分析了该尾矿库坝的应力变形特性,对不同堆积高程、不同工况下尾矿库坝的安全稳定性进行计算分析。此外采用拟静力法对地震荷载作用下尾矿坝的稳定性进行分析。结果表明,粗尾矿料会呈现出剪胀和软化力学特性,而细尾矿料则无明显剪胀;尾矿坝坝体内以压应力为主,坝体表面出现小范围拉应力区;高堆积高程,坝体倾向于发生深层滑动,坝体最小安全稳定性系数较大;干滩长度增大明显提高坝体稳定性;最后对该尾矿库的安全运行提出了一些针对性措施及建议。

MECHANICAL CHARACTERISTICS OF IRON MINE TAILING MATERIALS AND ANALYSIS ON DEFORMATION AND STABILITY OF TAILING DAM

Stability evaluation of tailing dam is the key procedure for tailing pond construction. The mineral types of tailings are quite complex, and are regional dependent. The characteristics of tailings are largely affected by mineral types, producing processes and deposited environments. This paper examines an ongoing designed iron mine tailings pond. It locates at Southwestern China. Specifically, this paper conducts a large number of physical and mechanical experiments for coarse and fine tailing materials, and obtained physical and mechanical parameters and applies them into tailing dam numerical simulation. It analyzes the stress and deformation properties of this tailing dam, and stability at different deposit elevations and different operation conditions. Furthermore, the quasi-static method is adopted to analyze the dynamic response of tailing dam under earthquake condition. Results show that coarse tailings present dilatancy and softening properties. In contrast, the dilatancy of fine tailings is not apparent. Compressive stress is commonly present inside tailing dam. There is a small part tensile stress area that appears on the surface of tailing dam. Tailing dam tends to happen deep slide at higher deposit elevation conditions. Additionally, the length of dry-beach has significant effects on dam stability. The ratio of dam stability increases with the increase of the length of dry-beach. In the end, some specific measures and suggestions are proposed for the tailing dam's safely operation. The results of this paper can provide a scientific basis for tailing dam design, construction and safely operation.