油松根系的固土力学机制

为深入了解林木根系固土力学机制,探讨不同条件下的根系固土作用,对油松根系进行了拉伸、拔出和根土复合体三轴试验。结果表明,油松根系的抗拉力随根系直径的增大成幂函数关系增加,而抗拉强度随直径的增大无明显变化规律;根系受拉的应力—应变曲线特征参数不同,以二次多项式模型拟合效果最好,均为单峰曲线,具有弹塑性材料的特征,极限应力和极限延伸率的大小与根系直径无明显的关系;根土界面最大摩擦力随着根径的增加呈现出近似线性的增长趋势。根径越大,根系越深,根土界面摩擦力就越大,进而对土壤的摩擦锚固作用就越强。相同根径时,根土复合体的抗剪强度随围压的增加而增大。相同围压下,根土复合体的抗剪强度随着根径的增加而增大。相同的根径和围压下,垂直埋根方式的根土复合体抗剪效果好于水平埋根方式。

Soil Reinforcement by Pinus Tabuliformis Roots

In order to understand soil reinforcement by root, to explore the role of soil-reinforcement by roots in soil conservation under different conditions, Pinus tabulaeformis roots anti-tensile strength and anchoring force, and the root-soil composite triaxial compression apparatus tests were carried out. Results showed that tensile resistance of Pinus tabulaeformis roots increased with increasing diameter according to a power function, but tensile strength had no obvious change rule with the increasing diameter. The root stress-strain parameters were different in different curves, and the quadratic polynomial model was very reasonable to describe its stress-strain response. All of them showed the single-peak curves with elastic-plastic material characteristics. Ultimate stress and ultimate elongation had no significant correlation with their diameters. There was an approximate linear relationship between root soil friction and root diameter. The larger diameter and deeper depth of root were, the bigger root-soil interface friction and the stronger anchoring role were. With the same diameter, it was found that root-soil complex shear strength increased with the increase of confining pressure. With the same confining pressure, shear strength of root-soil complex increased with the increasing diameter, and with the same diameter and confining pressure, the increasing influence with vertical root was better than that with horizontal root.