摘要
植物根系与土的相互关系非常复杂，将根土复合体当作由土体、根系所联系起来的有机体，提出基于根系形态特征的同土机理数值分析方法，研究在雨水侵蚀力和坡面径流侵蚀力作用下，不同的根系形态对土体的应力场和位移场的影响。选择常见护坡植物夹竹桃（Neniumindicum）作为研究对象，根据植物天然生长形态特征，建立植物根系数值模型，研究主侧根夹角度数不同的根系模型对边坡表层土体稳定性的影响。研究结果表明：运用有限元法能够模拟土体与根系的共同作用，可形象直观地体现植物根系对于边坡表层应力场和位移场的影响，根系的存在能够在土体中形成刚度较大的网状结构，网状结构能够有效的通过应力扩散作用将外力传递到周围土体，使边坡的应力向土层周围传递，从而增加了根系分布层整体的抵抗作用，能有效提高边坡表层土体整体稳定性，有效减小边坡表层土体位移量，边坡表层土体位移量随着根系长度的增加逐渐减小，根系主侧根夹角不同对边坡表层位移影响不同。主侧根夹角45°～60°，对减小边坡表层位移变化量最为有效。选择合适根系分布形态的护坡植物对稳定边坡表层土体具有不同的效果。植物根系对于边坡土体的稳定性仅限于边坡浅层土体，植物根系固土的作用主要是增加浅层土体的黏聚力，限制浅层土体的侧向位移，在土体表层形成加筋网络作用，提高边坡土体表层的稳定性。
As the relations between roots and soil are quite complex, this paper, considering the root-soil composite as an organism, brings forward the root form-based soil reinforcement numerical analysis method to study the effects of different roots on the stress field and displacement field of the soil under the conditions of rainfall and runoff erosions. The author selects a common slope plant, nerium indicum, as research object, and sets up the numerical models on the basis of natural root features to suggest the effects of roots with different included angles between taproot and lateral roots on the stability of slope surface soil. The results show that finite element method is capable in stimulating the root-soil interaction and intuitively reflecting the root effects on the stress field and displacement field of slope surface. Roots function as a rigid net structure in soil which transmits the slope stress to the deeper soil so as to enhance the resistance of the whole root distribution, improve the surface stability and decrease the displacement of surface soil. The displacement of slope surface soil reduces as the root length increases. Different included angles between taproot and lateral roots have different effects on the surface soil displacement, with the angle of 45°-60° most effective in reducing the displacement. The reinforcement of the rooted slope soil is restricted to the shallow layers and the roots serve to improve the cohesion, decrease lateral displacement of shallow soil and strength the stability of soil surface.
出处
《生态环境学报》
CSCD
北大核心
2012年第12期1966-1970,共5页
Ecology and Environmental Sciences
基金
教育部博士点基金项目(200802980005)
江苏省高校优势学科建设工程资助项目(2010)
关键词
主侧根夹角
根系形态
有限元
稳定性
位移
included angles between taproot and lateral roots
root form
finite numerical method
stability
displacement
