两种植物根分布特征及其对露天矿边坡表层的加固效果

为研究露天矿排土场边坡植物根的分布特征及加固效果,以海州露天矿西排土场为研究地点,以杠柳(灌木植物)和小蓬草(草本植物)为研究对象,每种植物选择5个样本,采用图片像素换算,确定不同深度(2、4、6、8、10、12和14 cm)土壤剖面上根面积比(RAR)分布;并采用拉力计测量两种植物根的抗拉力学特性;进一步通过纤维束模型计算,量化不同深度土壤剖面上根的附加黏聚力;并建立排土场理想边坡模型,研究两种植物根对边坡浅层稳定性的影响。研究结果表明,两种植物的RAR均值随着土壤剖面深度的增加而减小,每一个物种的RAR在不同深度土壤剖面存在显著性差异;两种植物根的抗拉力与根直径呈现幂律函数关系,且根直径相同时,小蓬草根的抗拉力高于杠柳;两种植物根附加黏聚力随深度的增加而减小,每一种植物根附加黏聚力在不同深度上存在显著性差异;RAR与根附加黏聚力随着根深度的增加,其数据离散性减小;两种植物根系对边坡起到明显的加固效果,杠柳和小蓬草根系加固后,安全系数分别提升了5.4%和9.0%。

Distribution Characteristics of Two Kinds of Plant Roots and Their Effects on Surface Reinforcement of Open-Pit Mine Slope

An ideal slope model of open-pit mine dump was established to investigate the influence of two plant roots,i.e.,Periploca sepium Bunge (shrub plant) and Conyza canadensis L. Cronq. (herb plant),on the stability of shallow slope. The west dump of Haizhou open-pit mine was selected as the research site. The distributions of root area ratio (RAR) on soil profiles at different depths (2,4,6,8,10,12 and 14 cm) were determined by using image processing technology;the tensile properties of the roots of the two plants were measured by a tension meter. Furthermore,the additional cohesion of roots on soil profiles at different depths was quantified by using the fiber bundle model. Results showed that the average RAR of the two plant roots decreased with the increase of soil profile depth,and the RAR of each individual plant root varied significantly at different soil profile depths. The relationship between tensile force and diameter of the two plant roots showed a power law function,and the tensile force of Conyza canadensis L. Cronq. root was higher than that of Periploca sepium Bunge root given the same diameter. Moreover,the additional cohesion of the roots of the two plants decreased with the increase of depth,displaying significant differences at various depths. The data dispersion of RAR and additional cohesion attenuated with the increase of root depth. In conclusion,the root systems of the two plants have obvious reinforcement effects on the slope. The safety factors of slopes reinforced by Periploca sepium Bunge and Conyza canadensis L. Cronq. increased by 5.4% and 9%,respectively.