寒旱环境植物根系增强边坡土体抗剪强度试验研究  

Research on Soil Shear Strength Reinforced by Vegetation Roots in Slope of Cold and Arid Environments

作　　者：赵玉娇[1] 胡夏嵩[1,2] 刘昌义[1] 窦增宁 李国荣[1] 

机构地区：[1]青海大学地质工程系,西宁810016 [2]中国科学院青海盐湖研究所,西宁810008

出　　处：《水土保持研究》2016年第4期212-220,共9页Research of Soil and Water Conservation

基　　金：国家自然科学基金项目(41162010;41572306);教育部长江学者和创新团队发展计划资助(IRT13074);长安大学西部矿产资源与地质工程教育部重点实验室开放基金资助(CHD2011SY016)

摘　　要：研究以地处西宁盆地的青海大学自建试验区作为研究区。采用草本、灌木植物单一种植和混合种植的方式,对种植植物边坡及未种植植物的素土边坡在A层（坡面地表0cm）、B层（坡面以下20cm）深度处的根—土复合体试样进行直接剪切试验,探讨了单一种植和混合种植两种种植方式下边坡土体抗剪强度的变化特征。结果表明：（1）单一种植的草本边坡在A层处根—土复合试样的粘聚力值分别为24.09,22.81kPa,均显著大于灌木边坡A层深度处根—土复合体试样的粘聚力值19.03,17.91kPa,且相对于素土试样的粘聚力值,草本根—土复合体试样的粘聚力值的增加幅度依次为104.67%,93.80%,灌木根—土复合体试样粘聚力值的增加幅度依次为61.68%,52.17%,显然,草本根—土复合体的粘聚力值增长幅度大于灌木植物;（2）随边坡土体深度的增加,单一种植方式下草本边坡根—土复合体试样粘聚力值呈递减趋势,即粘聚力值依次由24.09,22.81kPa递减至19.06,21.02kPa,这在一定程度反映出草本对边坡浅层土体抗剪强度的增强作用相对较为显著;（3）2种草本和灌木混合种植方式下根系对边坡土体抗剪强度的贡献值,均大于相应位置处2种草本和灌木单一种植方式下的贡献值,即混合种植条件下复合体的粘聚力值较单一种植时的增加幅度为0.13%~42.83%。该研究成果为定量评价边坡不同种植方式下植物根系增强边坡土体抗剪强度提供了理论依据,同时为进一步探讨植物根系增强边坡土体抗剪强机理具有一定理论价值和实际意义。The experimental site of this study is set up in Qinghai University,Xining Basin.We take root-soil composite systems in layer A（0cm）and layer B（20cm beneath the ground surface）on the slope with the planted herbs and shrubs by the approach of herbs and shrubs single planting and mixing planting,and from bare slope as shear test samples.And the characteristics of soil shear strength of the slope with herbs and shrubs are analyzed.The results show that：（1）the cohesion forces of root-soil composite systems in layer A of the slope with the2 herbs are 24.09 kPa and 22.81 kPa,respectively,both of which are higher than the cohesion forces（19.03 kPa,17.91kPa）of root-soil composite systems in layer A of the slope with 2shrubs.Compared with the cohesion force of bare slope,the increased cohesion force amplitudes of root-soil composite systems of herbs are 104.67%and 93.80%,respectively,the increased cohesion force amplitudes of root-soil composite systems of shrubs are 61.68% and 52.17%,respectively,so the increased cohesion force amplitudes of root-soil composite systems of herbs are much higher than shrubs;（2）the cohesion force of root-soil composite systems of the slope with 2herbs decreased from 24.09 kPa,22.81 kPa to 19.06 kPa,21.02 kPa with the increase of soil depth,which reflects the reinforcement by herb root in the shallow layer of the slope is significant;（3）the increasedcohesion force of root-soil composite systems of the mixture of 2herbs and 2shrubs is higher than that of single plant.The increased cohesion force amplitude of root-soil composite systems of the mixture of 2herbs and 2shrubs is 0.13%~42.83%.This study provides theoretical support for quantifying the contribution of vegetation roots to soil shear strength under different planting patterns,and it also has theoretical value and significance in further discussing the mechanism of soil shear strength reinforcement by roots on slope.

关 键 词：寒旱环境 根—土复合体 抗剪强度 直剪试验 

分 类 号：TU411.7[建筑科学—岩土工程]