林木根系黄土复合体的非线性有限元分析  

Nonlinear finite element analysis of woody roots-loess composite

作　　者：张超波[1] 陈丽华[1] 刘秀萍[1] 

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

出　　处：《北京林业大学学报》2008年第S2期221-227,共7页Journal of Beijing Forestry University

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

摘　　要：为了揭示林木根系固土的力学机制和林木固坡的抗滑机理,以林木根系黄土复合体为研究对象,采用三轴压缩试验结合有限元模拟的方法,研究了根土复合体的应力应变传递变化。将根土复合体视作单一均匀复合材料,采用非线性弹性模型中的邓肯--张(E--B)模型作为其复合模型,根据三轴压缩试验结果计算出的模型参数,运用非线性有限元法模拟三轴压缩试验中素土和复合根土复合体的应力场和应变场,绘制等值线图。结果表明:土体中加根能显著提高土体的承载力、限制土体的侧向变形、减少土体的沉降量,模拟结果与三轴压缩试验结果基本一致。可以将有限元方法用于造林边坡的应力应变场研究。In order to study the mechanism of woody root system in loess reinforcing and slope antisliding,triaxial compression tests combined with nonlinear finite element simulation were conducted on root-soil composite to investigate its stress-strain relationship.Throughout the whole process,root-soil composite was regarded as a single,uniform and complex material.One of nonlinear elastic models,i.e.,Duncan-Chang(E-B)model was chosen for the composite model.Based on the results of the triaxial compression tests,parameters of the model were calculated.With these parameters,stress field and strain field of loess and compound roots-soil composite in the triaxial compression tests were simulated by nonlinear finite element method,then isoline maps were easily drawn.Results indicate that adding roots in soil could significantly improve carrying capacity,restrict lateral deformation and reduce subsidence of the soil.The simulated results are primarily the same as the triaxial compression tests,which suggests that nonlinear finite element method could be utilized to analyze stress and strain field of forested slope.

关 键 词：三轴压缩试验 根系--黄土复合体 邓肯--张(E--B)模型 非线性有限元 

分 类 号：S714[农业科学—林学]