林木根系与黄土复合体的抗剪强度试验研究  

Study on the shear strength of forest root-loess composite.

作　　者：刘秀萍[1] 陈丽华[1] 宋维峰[1] 

机构地区：[1]北京林业大学水土保持学院,水土保持与荒漠化防治教育部重点实验室

出　　处：《北京林业大学学报》2006年第5期67-72,共6页Journal of Beijing Forestry University

基　　金："973"国家重大基础研究项目(2002CB111502);国家自然科学基金项目(30571531)

摘　　要：为了深入了解林木根系在增强黄土抗剪强度中的作用机理,该文用三轴压缩试验方法研究了林木根系与黄土构成的复合体的应力--应变及强度特性,探讨了不同根系直径、根系分布方式、复合体含水量和围压下的土体抗剪强度.试验证明,根系--土壤复合体抗剪强度τf与法向正压力σ的关系符合库仑定律,即τf=σtan+C.由试验结果可知,根系直径相同时,复合体含水量从12.72%增至15%,水平根系的根土复合体的抗剪强度减小,垂直根系和复合根系的复合体抗剪强度增加;复合体含水量一定时,3种分布方式的根土复合体的抗剪强度都随根系直径的增加而增大;根系直径和复合体含水量一定时,复合根系的根土复合体的抗剪强度最大,垂直根系次之,水平根系最小.In order to understand the effect of forest roots on loess shear strength better, triaxial compression tests were carried out to determine the stress-strain and strength characteristics of forest root-loess composite. The shear strength of the composite was investigated in terms of various root diameter, root distribution, water content of composite and confining pressure. Results proved that the direct shear strength can be described by Coulomb Equation, i e τf = σtanφ ＋ C. It was found that with the increase of water content from 12.72% to 15 % , the shear strength of horizontal composite decreased, while the shear strength of vertical and complex root-loess composite increased. When the water content of composite in the steady state, shear strength of three kinds of root-loess composites increases with the increase of root diameter. And when the diameter of root system and water content of the composite are constant, the forest root-loess composite of complex root system has the largest shear strength, then the vertical root system, and the horizontal one is the least.

关 键 词：根系-土壤复合体 三轴压缩试验 刺槐 抗剪强度 

分 类 号：S714.7[农业科学—林学]