冻融作用下草本植物根系加固土体试验研究

为了研究植物根系在冻融作用下对边坡土体的加固效应，取哈尔滨、东营、合肥等地公路常见的3种草本植物根系作为研究对象，基于植物根系与土体之间的界面摩擦效应，对不同植物根系在不同次数冻融作用后的根-土复合体进行了拉拔试验以及直剪试验。结果表明：结缕草根系与土体之间的摩擦效应最为显著，加筋效果最好；狗尾草的根系与土体之间的摩擦效应最差，但狗尾草根系抗冻性较好。根-土复合体模型的抗剪强度随冻融作用次数的增加发生变化，体现在黏聚力不断减小，后趋于稳定；内摩擦角先增大后减小，之后趋于稳定。所得结果可为植物护坡加固工程以及加筋土作用机理研究提供数据参考。

Experimental study on the reinforcement of herbaceous plant roots under freezing-thawing cycles

In order to study the reinforcement effect of plant roots on the slope soils under freezing-thawing cycles, three types of herbaceous (Zoysia japonica, Eleusine indica and Setaria viridis) roots common to Harbin, Dongying and Hefei highways were selected as research objects. Based on the interface friction effect between plant roots and soil, pull-out test and direct shear test were carried out on root-soil composites of different plant roots after various freezing-thawing cycles. The experimental results showed that the friction effect between root systems of Zoysia japonica and soil is most significant, and the reinforcement effect is the best. The friction effect between root systems of Setaria viridis and soil is least significant, and the reinforcement effect is worst. However, the frost resistance of Setaria viridis is better. The shear strength of the root-soil composite model changes with the number of freezing-thawing cycles, showing that the cohesion force decreases continuously and then tends to be stable; the internal friction angle increases first and then decreases, and then tends to be stable. The obtained results may be useful for researching plant slope protection and functional mechanism of reinforced soil.