草本植物根系对高液限土的加固效应

Reinforcing Effect of Herb Roots on High Liquid Limit Soil

[目的]探索草本植物根系对高液限土的加固效应,为工程中合理预估植物根系在高液限土质边坡防护中的作用提供依据。[方法]以高羊茅根系及其与高液限土壤构成的根—土复合体为研究对象,通过一系列室内直剪试验分析高液限土含水率和含根量对抗剪强度的影响。[结果]在土样中掺加根系可以显著提升其黏聚力,小幅提升其内摩擦角。根系对土体的加固效果随着含水率增加呈现先上升后减小的趋势。不同含水率梯度下根—土复合体的最优含根量有所区别,对于20%和25%含水率的土样,其最优含根量大致在0.3%附近,对30%含水率土样在0.4%附近,对35%~45%含水率土样在0.5%附近。[结论]草本植物根系可以有效抑制高液限土的水敏性,且在不同含水率梯度下根系发挥的作用差异显著。

[Objective] The strengthening effect of herbaceous plant root system on the high liquid limit soil was explored to provide the basis for reasonable estimation of the plant root system about the effect of slope protection on the high liquid limit soil.[Methods] Root-soil complexus of tall fescue couch grass root and high liquid limit soil were taken as research object, and the influences of water content and root amount on shearing strength of the complexus were explored through a series of indoor direct shear tests.[Results] The cohesion ability can be greatly improved by adding root system to soil samples, and the internal friction angle was also increased slightly. The reinforcement effect of root system on the soil increased initially with the increase of moisture content, decreased as moisture continued increasing. There existed difference for optimal root amount with regard to reinforcement under different moisture content of the complexus. When soil moisture content was 20%~25%, 30%, and 35%~45%, the optimal root amount was around 0.3%, 0.4%, and 0.5%, respectively.[Conclusion] The herbaceous plant root system can effectively suppress the water sensitivity of high liquid limit soil. There is significant influence on different root systems for different moisture content.