黄土高原刺槐根系固土的力学增强效应评价  

Triaxial Compression Test of Loess-Root Composites to Evaluate Mechanical Effect of Roots on Reinforcing Soil

作　　者：张超波[1] 陈丽华[1] 刘秀萍[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,北京100083

出　　处：《水土保持学报》2009年第2期57-60,共4页Journal of Soil and Water Conservation

基　　金：国家自然科学基金项目(30872067,30571531);国家“973”重大基础研究项目(2002CB111502)

摘　　要：为了评价根系固土的力学增强效应,采用三轴压缩试验研究了中国西北黄土高原上的刺槐（Robinia pseudoacacia）根系-黄土复合体。结果表明：根土复合体极限主应力差最多时候比素土提高了70%,复合体抵抗剪切破坏的能力比素土有明显提高;根系能显著增强土壤黏聚力,复合体黏聚力在含水量12.7%时比素土提高了38%-162%,在含水量12.7%时比素土提高了22%-50%,对土壤内摩擦角影响较小;在含垂直根、水平根和复合根的3种复合体中,根体积比高的复合根土复合体比根体积比低的水平根与垂直根土复合体具有更高的增强土壤抗剪强度的特性;土壤含水量的增加直接导致土壤内部黏聚力下降,对素土和根土复合体抗剪强度产生的是负面效果。In order to evaluate mechanical effect of roots on reinforcing soil, triaxial compression test was carried out to study composite of soil and roots of Robinia pseucdoacacia from Loess Plateau in northwest China. The results showed that the ultimate principal stress difference （σ1-σ3）f of soil-root cnmposite was 70% higher than that of plain soil at the most. Root significantly contributed to the increase of soil cohesion, which was 38%-162% when soil water content was lower at 12.7% and was 22%-50% when soil water content was higher at 20.0 %, but little impact on soil internal friction angle. Among designed vertical roots, horizontal roots and composite roots, the reinforcing effect of composite roots, which were higher root volume ratio, was more effective than horizontal roots and vertical roots, which were lower ratio. Soil water content was negatively relative to shear strength of plain soil and soil-root composite because the rise of soil water content directly induced decline of internal cohesion of soil.

关 键 词：刺槐 含水量 根土复合体 三轴压缩试验 抗剪强度 

分 类 号：S714.7[农业科学—林学]