林木根系固土作用数值分析  

Numerical analysis on the effects of forest root system on soil reinforcement

作　　者：宋维峰[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

出　　处：《北京林业大学学报》2006年第S2期80-84,共5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：林木根系的固土作用是通过影响土体的应力、应变(位移)状态来实现的.该文将根土复合体看作是由土体、根系以及土体与根系之间的接触单元所联系起来的有机体,采用Duncan-ChangE-μ模型和非线性界面单元模型对根系固坡问题进行了应力应变分析,以油松为对象,模拟了油松根系与黄土相互作用的应力场,探索了有限元数值分析方法在根系固土机理研究领域的应用.研究结果表明,根系能使坡面表层的应力传递到土层深层,并弱化一定深度土层土体的应力,尤其是根底边缘附近的浅层土体应力减小的幅度较大,表明根系固土的影响范围局限于土体浅层.采用有限元法计算坡面在无林与有林两种条件下的边坡安全系数分别为1·821和1·984,有油松根系存在的边坡其安全系数比天然边坡计算的安全系数提高了10%,说明根系具有一定的固土作用.Forest root system affects the soil stress and strains and contributes to soil reinforcement. An analysis of stress and strain in the root-soil composite, which combines roots, soils, and an interface element, was presented using the Duncan-Chang E-μ model and a nonlinear-interface-element model. In this research, a finite element numerical analysis method was applied to simulate the stress field resulting in a composite of Pinus tabulaeformis roots and soils. Results show that roots can transmit the stress from surface to deep soil, and can reduce soil stress within the surface soil layer, showing that the effects of soil reinforcement by root system are limited to the surface soil. Using finite element method, the slope safety indices are 1.821 and 1.984 under non-forested and forested conditions, respectively. The slope safety index of a pine slope becomes 10% higher than that of a natural slope, indicating that root system has significant effects on soil reinforcement.

关 键 词：油松 根系 根土复合体 应力 数值分析 固土 

分 类 号：S714[农业科学—林学]