根系生态护坡的机理及试验研究

针对公路边坡开挖可能导致生态破坏和边坡失稳等问题,分别从理论上分析植物根系生态护坡的力学机理和从试验上研究根系的抗拉锚固能力.理论研究表明,根系提高土的抗剪强度主要是通过根-土接触面的摩擦力把土中的剪应力转换成根的拉应力来实现的;根系在生长时分泌了大量高分子聚合物,将其表面附近的土颗粒聚集起来,从而抵抗边坡土体受水流等因素的侵蚀.刺槐幼株根系的抗拉强度试验研究表明：侧根抗拉强度最大值大于主根的抗拉强度最大值,其最大值可达91.41 MPa;与HPB235钢材强度设计值210 MPa相比,该株刺槐根系的抗拉强度可达到其1/4～1/2.

Research on Mechanism and Test of Roots for Ecological Protection Slope

According to the ecological damage and instability of highway slopes, a theoretical research on the mechanism of ecological protection slope and an experimental study of the tensile of roots for its anchoring ability were presented. It has been proved in theory that soil shear stress is transferred to roots tensile stress through the frictional force of root-soil contact surface to improve soil shear strength, and soil granules around roots surface are aggregated through much high polymer produced from the growth of roots to resist slope soil erosion by rain. The tests have been based on the tensile strength of the roots of young robinia pseudoacacia. The results have shown that the maximum tensile strength of lateral root is higher than the maximum tensile strength of taproot, and the maximum value is up to 91.41MPa. Compared with the design tensile strength 210MPa of steel HPB235, its tensile strength is as great as 1/4~1/2.