不同土壤生物工程措施根系附加黏聚力研究

Study on the Adhesion Cohesion of Root Systems in Different Soil Bioengineering Measures

[目的]研究4种不同土壤生物工程措施对边坡土体抗剪强度的提高作用。[方法]设置了一处长40 m的人工边坡,在边坡上使用扦插、灌丛垫、层栽与梢捆4种土壤生物工程措施,并在施工8、12个月后分别开展根系现场调查,在实验室进行单根抗拉试验,并引入RWM模型量化研究4种不同土壤生物工程对边坡抗剪强度的提高作用。[结果]旱柳根系抗拉强度随根系直径增大逐渐减小,能产生显著的根系加筋作用;随着土层深度的增加,根的面积比减小,4种土壤生物工程措施完工12个月后的各径级的根系截面积比率(RAR)相比于8个月后提高43.75%~69.38%;土壤生物工程可以明显提高边坡的抗剪强度,随着根系的发展,12个月以后各种措施附加黏聚力比8个月时有明显的增长。20 cm土层深度时灌丛垫与梢捆措施附加黏聚力高于扦插和层栽,且根系所产生的附加黏聚力最大,对边坡的浅层土壤的加筋作用优于另外2种措施。20 cm深度以下灌丛垫与梢捆措施根系附加黏聚力逐渐下降,而扦插与层栽措施附加黏聚力逐渐增加,对深层土壤具有一定的锚固作用。[结论]研究可为土壤生物工程技术在农田水利护坡中的广泛应用提供量化评价方法和理论指导。

[Objective]The effect of 4 different soil bioengineering measures on the shear strength of slope soil was studied.[Method]An artificial slope of 40 m was set up in the experiment.Four kinds of soil biological engineering measures were used on the slope,including cutting,shrub mat,layer planting and bundling,and the root field investigation was carried out in 8 months and 12 months after construction. Single tensile test was carried out in the laboratory,and RWM model was introduced to quantify the effect of 4 different soil biological engineering on the shear strength of the slope.[Result]The results showed that： the tensile strength of the root system decreased with the increase of root diameter,which could produce a significant root and reinforcement effect. With the increase of soil depth,the area ratio of the root was decreased,and the RAR of the four soil bioengineering measures after 12 months was increased by 43.75% to 69.38% compared with that in 8 months.Soil bioengineering can obviously improve the shear strength of the slope. With the development of the root system,the adhesion of various measures after 12 months is significantly higher than that in August. Scrub pads when 20 cm soil depth and tip add bundle of measures of cohesion is higher than cutting and planting,and the root system produced by the additional cohesive force,the largest of shallow soil on the slope reinforcement effect better than the other two measures. The adhesion cohesion of the root system was gradually decreased with the thickness of the thicknes and the tip bundle,and the adhesion of the cuttings and bedding was gradually increased,which had a certain anchoring effect on the deep soil. [Conclusion]The research results provide quantitative evaluation method and theoretical guidance for the wide application of soil bioengineering technology in farmland water conservancy slope protection.