Vegetation has good application in slope stabilization, but its beneficial effects on reinforcing topsoil are generally limited by the soil properties it was cultivated in. This study aims at evaluating the strength improvements of sand-root composite by treating with polyurethane polymer and hence investigating the mechanism of polymer-root-soil interactions. Vegetation roots were selected and mixed with dry sand and polymer solution to prepare remolded specimens. A series of experimental tests were then performed at different percentages of root content (0, 0.4, 0.8, 1.2, and 1.6 % by weight of dry sand) and polymer content (1, 2, and 4% by weight of dry sand) to evaluate the shear parameters and unconfined compressive strength (UCS). The combined mechanism was studied by scanning electron microscopy (SEM) images. The results showed that the strengthening effect has greater efficiency with higher polymer content. Through varying contents of vegetation root, it was found that low root content induced an undesirable weakening effect on the strength of the treated soil. However, this situation was somewhat improved with the increase in root content. The good flexibility of polymers not only promote the capacity of soil to energy absorption, but also impart good ductility to soil. The presence of polymers greatly strengthens soil stability due to its special network structure, by which the improved shear resistance at the root-soil interface provides sufficient anchorage effect for the tensile strength of roots to be fully mobilized. Overall, the synergistic effect of root reinforcement and polymer treatment has the potential for its use in soil stabilization.

植被在边坡稳定方面具有良好的应用，但其对表土加固的有益作用通常受到其耕种土壤特性的限制。本研究旨在评估通过用聚氨酯聚合物处理而提高的砂根复合材料的强度，并研究其机理。聚合物-根与土壤的相互作用。选择植被根并将其与干砂和聚合物溶液混合以制备重塑的标本。然后以不同百分比的根含量（干砂重量的0、0.4、0.8、1.2和1.6％）和聚合物含量（干砂重量的1、2和4％）进行一系列实验测试，评估剪切参数和无侧限抗压强度（UCS）。通过扫描电子显微镜（SEM）图像研究了结合的机理。结果表明，随着聚合物含量的增加，强化效果提高。通过改变植被根的含量，发现低根含量对处理后的土壤强度产生了不利的减弱作用。但是，随着根含量的增加，这种情况有所改善。聚合物的良好柔韧性不仅促进土壤吸收能量的能力，而且赋予土壤良好的延展性。聚合物的存在由于其特殊的网络结构而极大地增强了土壤稳定性，通过这种结构，根-土界面处的抗剪强度得到了改善，从而为充分发挥根的抗张强度提供了充分的锚固效果。总体而言，根部加固和聚合物处理的协同效应具有将其用于土壤稳定化的潜力。