Soil bioengineering using vegetation is an environmentally friendly solution to maintain the stability of shallow earthen slopes. To explore the microscopic mechanical reinforcement mechanism of plant roots on slope stabilization, the stabilities of three soil slopes covered by live grasses in different root morphologies under intense rainfall were examined extensively by both experimental tests and numerical simulations. Highly-bionic root morphological models were developed and validated to simulate the changes in root morphologies and root axes contact-forces. It was revealed that the roots in a uniform morphology effectively strengthened the slope toe through strong shear resistance in the middle and anchoring force at the end of root system; the roots in an upside-down triangular morphology maintained the stability of upper soil slope through its wide upper roots, which extended deeply into the slope interior and hence gave full play to tensile force. Compared with the previous two, the roots in a fusiform morphology had the weakest soil reinforcement and the slope experienced a series of retrogressive failures until the upper residual slope soil collapsed eventually. The significant increase in shear strength of root-soil composites derived primarily from the increase in cohesion. The root axis with the strongest contact-force during slope failure was not necessarily the longest taproot in the middle of root system but a single-root on one side.

中文翻译：

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强降雨条件下植被土质边坡稳定性试验研究

利用植被的土壤生物工程是维持浅土坡稳定性的环保解决方案。为了探索植物根系对边坡稳定的微观力学加固机制，通过实验测试和数值模拟，对不同根系形态的活草覆盖的三个土坡在强降雨条件下的稳定性进行了广泛的研究。开发并验证了高度仿生根形态模型，以模拟根形态和根轴接触力的变化。结果表明，形态均匀的根系通过根系中部较强的抗剪力和末端的锚固力，有效加固坡脚；根系呈倒三角形形态，其上根部较宽，深入坡体内部，充分发挥拉力，维持了上层土坡的稳定性。与前两者相比，梭形形态的根部土体加筋力最弱，边坡经历了一系列的后退破坏，直至上部残坡土体最终塌陷。根-土复合材料剪切强度的显着增加主要源于内聚力的增加。边坡破坏时接触力最强的根轴不一定是根系中部最长的主根，而是一侧的单根。