中文摘要：

通过对贫瘠土壤环境下生长1年的香根草根系在土中分布的统计分析，得到了香根草根系数量和根系横截面积沿土层深度变化的规律，并基于香根草根系抗拉强度的一系列试验，研究了根系抗拉强度随其直径和长度而变化的特性。结果表明：香根草根系的数量和横截面积沿深度呈递减趋势，但大部分根系分布在较深的土层内；随着根径和长度的增长，抗拉强度逐渐下降，根径的影响更加明显。在此基础上，改进了现有的根系抗拉强度计算模型，并给出了针对香根草的模型参数。计算结果和实测数据非常吻合，证明了该理论模型的可靠性，为根土复合体抗剪强度研究和植物边坡稳定分析提供了理论基础。

英文摘要：

Through the statistical analysis on root system of Vetiveria zizanioides which have grown in poor soil for one year, the distribution laws of roots’ number and cross-sectional area along the depth of soil layer were obtained. The analysis results show that both the number and the cross sectional area of roots decreased with the depth increase, but most of the roots distributed in deeper soil layer. Based on a series of indoor tests on the roots of V. zizanioides, the tensile strength characteristics which are related with the diameter and length of roots have been studied. The tested results indicate that, with the increases of diameter and length of roots, theirs tensile strength decreased gradually, and the effect of root diameter on tensile strength was more obvious. At the same time, the existing calculation model of roots tensile strength was improved, and the model parameters for V. zizanioides were given. The calculated results were in good agreement with those of the tested results. it is proved that the theoretical model is reliable, which provides a theoretical foundation for the research of shear strength of root-soil composite, so that this is also an essential prerequisite for stability analysis of plant slope.