黑麦草根系加固粘土的剪切强度性能研究

Study on shear properties of ryegrass root-reinforced soil

植被在增强边坡稳定性方面有着积极的作用,其作为一种兼顾生态保护和边坡治理的护坡方式,在工程实践中得到了广泛的应用。为了研究植物根系加筋土的抗剪特性,以室内培育的黑麦草根系为加筋土的筋材,制备了不同含根量和含水率的重塑试样,通过直剪试验分析其抗剪强度特性的变化规律。研究结果表明:黑麦草根系加筋增强了土体的抗剪强度,表现为粘聚力随着含根量的增长呈明显增长趋势,最大粘聚力增长可达253%,而内摩擦角的变化较不明显。土体的抗剪强度随含水率的增加有着明显的降低,这归因于根-土界面抗剪强度的降低,使得根系更易被拔出土体而导致较差的拉筋效果。当土体含水率增加时,根系在为加筋土提供抗剪强度方面的作用变得尤为重要。

Vegetation provides a natural bioengineering method to prevent slope failure,which has been widely used in engineering practice.In order to study the shear properties of root-reinforced soil,remolded specimens were prepared by incorporating ryegrass roots.The effect of root content and water content on the shear strength parameters of root-reinforced soils was investigated by conducting direct shear tests.The experimental results showed that the presence of root noticeably improves the shear strength of soils.The cohesion increases with increasing root content which may reach up to a 253%increase comparatively,however,the change in internal friction angle is not obvious.The additional shear strength provided by roots decreases with water content,mostly due to the decrease of shear strength at the root-soil interface,in which case the embedded roots may slip through the soil more easily during shearing rather than experience rupture in tension.The role of roots in providing shear strength for reinforced soil turns to be more important when subjected to an increasing water content.