3种植物根-土复合体抗剪特性对比分析  

The Shear Property Comparison of Three Roots-soil Composites

作　　者：格日乐[1] 张成福[1] 蒙仲举[1] 斯琴[1] 吴映东 

机构地区：[1]内蒙古农业大学生态环境学院,呼和浩特010019

出　　处：《水土保持学报》2014年第2期85-90,共6页Journal of Soil and Water Conservation

基　　金：国家自然科学基金项目(41161046)

摘　　要：采用直剪仪对3种植物重塑的根-土复合体及素土进行室内剪切试验,探讨其抗剪强度以及土壤含水率对抗剪强度的影响,结果表明:在相同径级(d=1.25mm)和快剪条件下,在0.8m的浅层土范围,3种植物根-土复合体抗剪强度相对于素土的增长率大小顺序为柠条(60%)>沙棘(35%)>杨柴(29%);3种植物根-土复合体粘聚力值相对于素土的增长率大小顺序为柠条(39%)>杨柴(38%)>沙棘(28%);而3种植物根-土复合体的内摩擦角相对于素土的增长率值均为负值,分别为-2%(柠条),-14%(沙棘)和-21%(杨柴)。因此,可以认为粘聚力的增加对提高根-土复合体抗剪强度起到重要的作用。土壤含水率对3种植物根-土复合体抗剪强度的影响结果显示:随着土壤含水率的增加,3种植物根-土复合体抗剪强度及粘聚力均呈现先增大后减少的趋势,且植物种不同,其抗剪强度和粘聚力峰值出现时的土壤含水率不同。通过上述研究得出,植物根系增强土壤抗剪强度的作用大小不仅受植物种的影响,还与土壤含水量密切相关,植物种不同,其根系增强土体抗剪强度的作用达到最佳时所要求的土壤水分条件亦不同,存在最适含水量或含水量区域。The shearing strength of pure soil and the roots-soil composite of three vegetation species and the impact of soil moisture on the shearing strength in laboratory were studied. The three vegetation included Caragana korshinskii, Hippophae rhamnoides, Hedysarum fruticosum. The relative shear strength com- pared with pure soil was 60% for Caragana korshinskii, 35% for Hippophae rhamnoides, and 29% for Hedysarum fruticosum with the diameter class of 1.25 ram, fast shear, and soil depth less than 0.8 m. The relative roots-soil composite cohesion compared with pure soil was 39% for Caragana korshinskii, 58% for Hedysarum fruticosum and 28% for Hippophae rhamnoides. The relative internal friction angle compared with pure soil was - 2% for Caragana korshinskii, -- 14% for Hippophae rhamnoides, and -- 21% for Hedysarum fruticosum, respectively. The above results denoted that the shear strength of roots-soil com- posite increased with the increase of its cohesion. With the increase of soil moisture, the shear strength and cohesion of three roots-soil composite increased firstly and then decreased. The peaks of the shear strength and cohesion appeared differently with different soil moisture and plant species. Vegetation species and soil moisture determined the shear strength and cohesion of roots-soil composite.

关 键 词：根-土复合体 抗剪强度 黏聚力 内摩擦角 土壤含水率 

分 类 号：S714.7[农业科学—林学]