铁尾矿库无土植被护坡力学加固效应分析

针对铁尾矿库水土流失和库区生态环境的修复问题,通过开展水力侵蚀室内试验,研究了高羊茅、星星草、野牛草和裸坡4种工况下尾矿库边坡的径流模数时变规律、侵蚀模数时变规律、入渗与植被截流率和植被全截流规律。通过开展根-尾矿砂复合体的室内直剪试验,研究在不同含根量和不同生长时间的情况下野牛草根-尾矿砂复合体黏聚力和内摩擦角的变化规律,分析野牛草根系含量和生长时间对铁尾矿砂抗剪强度的影响,进而分析野牛草根系含量和生长时间对铁尾矿砂抗侵蚀能力的影响。确定了提高铁尾矿砂抗剪强度和边坡抗侵蚀能力的最佳含根量及根系最佳生长时间。结果表明:野牛草是铁尾矿库无土植被护坡工程中的优选草种,野牛草根作为铁尾矿砂的加筋材料能够明显提高尾矿砂的抗剪强度和边坡的抗侵蚀能力;根-尾矿砂复合体的黏聚力随根系的生长时间和含根量的增加先逐渐增大,后逐渐减小,但均高于未加野牛草根时的黏聚力;野牛草的最优生长时间为3个月、最优含根量为0.20%,野牛草根系的生长时间和含根量对铁尾矿砂内摩擦角的影响很小。

Analysis of reinforcement effect of soilless vegetation slope protection in iron tailings reservoir

Hydraulic erosion indoor experiments are conducted by considering the soil erosion of the iron tailings pond and the restoration of the ecological environment of the reservoir area. The timevarying law of runoff modulus, the time-varying law of erosion modulus, the rate of total infiltration and vegetation interception and full interception of vegetation of the tailings pond slope are studied under the four working conditions of tall fescue, star grass, bison grass and bare slope. Based on the indoor direct shear test of root-tailing sand complex, the variation of cohesion and internal friction angle of buffalo root-tailing sand complex under different root contents and growth times are studied. Furthermore, the effects of root content and growth time of the buffalo grass on the erosion resistance of iron tailings sand are analyzed. The optimum root content and root growth time of the root-tailing sand shear strength and slope erosion resistance are determined. The results show that the buffalo grass is the preferred grass species in the soilless vegetation slope protection project of iron tailings reservoir. The buffalo grass root serving as the reinforcement material of iron tailings sand can dramatically improve the cohesive force of tailings sand and the slope erosion resistance. The cohesive force of root-tailing sand gradually increases and then decreases with the increase of root growth time and root content, which is always higher than that without buffalo grass. The optimal growth time of the buffalo grass is three months, and the optimal root amount is about 0. 20%, which has little effect on the internal friction angle of iron tailings reservoir.