寒区尾矿力学特性的环境响应试验

Experiment on Environmental Response of Tailings' Mechanical Properties in Cold Regions

通过室内冻融循环后的直剪试验,研究了不同次数冻融循环对寒区干堆尾矿物理力学特性的影响。在相同冻融循环条件下,分别设置了开放和密封的试验环境以研究试样在不同冻融循环次数后的表面龟裂、含水率、抗剪强度、粘聚力和内摩擦角的环境响应。运用数学拟合函数获取了干堆尾矿力学特性对环境的响应关系。试验结果表明:开放组试样表面在经历6次冻融循环后开始出现龟裂,而密封组试样表面无明显变化;开放组和密封组试样的含水率分别在12次和9次冻融循环后趋于稳定;随着冻融循环次数的增加,开放组试样的抗剪强度、粘聚力和内摩擦角均增大,而密封组试样的抗剪强度、粘聚力和内摩擦角均减小。

The direct shear tests were conducted after laboratory freezing-thawing cycles, for studying the impact of freeze-thaw cycles on physico-mechanical properties of dry stack tailings in cold regions. After different freeze-thaw cycles, the tested sample responding to the open and sealed environment with the same cycle, respectively, were all studied in terms of its surface cracking, moisture content, shear strength, cohesion and internal friction angle. Mathematical fitting function was adopted to obtain a response relationship between mechanical characteristics of dry stack tailings and environment. Test results indicated that, cracks were observed when the unsealed group specimens were subjected to six freeze-thaw cycles. In contrast, no obvious change was found on the surface of sealed group specimens. The water content of unsealed and sealed specimens tended to be stable after 12 and 9 freeze-thaw cycles, respectively. As freeze-thaw cycles increasing, the shear strength, cohesion and internal friction angle of unsealed specimens all grew. On the contrary, these indexes of the sealed specimens all decreased.