张家口地区高羊茅根系对浅层边坡的力学固土研究

Study on Mechanical Soil Fixation of Tall Fescue Roots on Shallow Slope in Zhangjiakou Area

为了建立根土复合体抗剪强度极限值估算模型,本研究通过高羊茅根系拉拔试验研究,基于室内直剪试验测定的根土复合体抗剪强度参数对Wu模型进行修正,并通过修正后的Wu模型确定高羊茅根系附加黏聚力的增长情况。结果表明:不同土体及不同植被的θ值不同,θ值与法向压力及含水率有关,且θ角度的变化随根面积比的增大而增大;夹角系数k随含水率的增高先增大后减小,其峰值点也会随含水率的增大而提高;平均拉拔强度与高羊茅根系直径呈现幂函数关系;根土复合体抗剪强度破坏趋势和素土大致相同,剪应力略高于素土。本研究为快速量化根土复合体的抗剪强度及评估植被稳固浅层边坡稳定性提供了理论支撑,为稳固浅层滑坡问题提供了解决方案。

In order to establish an estimation model for the shear strength limit of root soil composite,this study conducted a pull-out test of tall fescue roots,modified Wu's model based on the shear strength parameters of root soil composite measured through indoor direct shear tests,and determined the growth of additional cohesion of tall fescue roots through the modified Wu's model.The results show that the values of different soil and vegetation are different,and theθvalues are related to the normal pressure and water content,and the change ofθangle increases with the increase of root area ratio;The includedθangle coefficient k first increases and then decreases with the increase of water content,and its peak point will also increase with the increase of water content;There is a power function relationship between the average pulling strength and the root diameter of tall fescue;The failure trend of the shear strength of the root soil composite is approximately the same as that of the plain soil,and the shear stress is slightly higher than that of the plain soil.This study provides theoretical support for rapidly quantifying the shear strength of root soil composites and evaluating the stability of vegetation stabilized shallow slopes,as well as providing solutions to the problem of stabilizing shallow landslides.