生态防护主要是利用植物根系来达到固坡和防护的目的，以植物根系分布特征和固坡机理分析为基础，通过土工直剪试验，系统研究了根-土复合体的抗剪强度，并分析了根系密度对的抗剪强度的影响。研究结果表明草本植物根系的90%集中分布在距地表0~30 cm的土层内；根-土复合体的抗剪性能与根系的抗拉强度和根的面积比率有关；而且随正应力的增大而增大，近似呈线性关系，较无根系土的黏聚力增加一倍多，根系对土体抗剪强度的提高主要是由黏聚力的增大来实现的；根系密度对根-土复合体抗剪强度有明显影响，根-土复合体抗剪强度增量与根系密度之间具有良好的二次多项式的相关关系。%Plant roots is mainly used to achieve the goal of slope-fixing and protection in the ecological protection , shear strength of soil-roots composite was studied and the influence of root density on soil strength was analyzed using soil direct shear test on the basis of plant roots distribution and slope-fixing mechanism analysis. The results showed that 90% of the herbaceous plant roots is distributing within 0~30 cm from the surface of the soil. Shear strength of soil-roots composite and tensile strength of root have influence with area ratio of root and increase more than doubled than the cohesion of soil without roots with the increase of normal stress by approximate linear trend. The soil shear strength is mainly implemented by the increase of cohesion by root system. Root density has significant influence on the shear strength of soil-root composite which has well quadratic polynomial correlation with the increment of soil-root composite shear strength.
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