拉拔-水平荷载作用下根-土复合体变形特征分析

Analysis of the deformation characteristics of root-soil composite body under pull-horizontal load action

摘要

生态护坡技术主要通过植物根系固结土体来提高土体抗剪强度，增强边坡浅层稳定性。以往植物根系护坡研究多集中在根-土复合体强度特征方面。基于数值模拟方法，研究逐级拉拔-水平耦合荷载作用下根-土复合体变形规律。基于根系和土体的特征位移，分析拉拔-水平耦合荷载作用下根-土复合体破坏模式，明确受荷过程中邻近土体位移演化规律。通过对比拉拔和拉拔-水平耦合荷载作用下根-土复合体变形特征差异，分析水平荷载对根-土复合体变形的影响，确定不同荷载下植物根系固土能力。结果表明：根-土复合体逐级拉拔情况下，低荷载时，根系与土壤间尚能保持一定程度的连结；但当荷载超过临界值，根系与土壤间的相互作用减弱，最终导致根-土复合体的破坏。根系的存在不仅改变了土壤的位移模式，还对土壤的力学响应产生了重要影响，尤其是在荷载较低时，根系的支撑作用更为明显。

Abstract

The ecological slope protection technology mainly improves the soil shear strength and enhances the stability of the shallow layer of the slope through the root system of plants. Previous studies on plant root slope protection were mostly focused on the strength characteristics of the root-soil composite body. Based on the numerical simulation method, the deformation law of the root-soil composite body under the gradual pulling-horizontal coupled load action is studied. Based on the characteristic displacement of the roots and soil, the failure mode of the root-soil composite body under the pulling-horizontal coupled load action is analyzed, and the evolution law of the displacement of the adjacent soil under the load is clarified. By comparing the deformation characteristics of the root-soil composite body under the pulling and pulling-horizontal coupled load actions, the influence of the horizontal load on the deformation of the root-soil composite body is analyzed, and the plant root retention ability under different load conditions is determined. The result show that: under the gradual pulling condition of the root-soil composite body, the root system and soil can still maintain a certain degree of connection at low load; but when the load exceeds the critical value, the interaction between the root system and soil weakens, and ultimately leads to the failure of the root-soil composite body. The existence of roots not only changes the displacement pattern of soil, but also has an important influence on the mechanical response of soil, especially at low load, where the support of roots is more obvious.

关键词

植物根系 / 土体 / 变形 / 生态护坡 / 稳定性

Key words

plant roots / soil mass / metamorphosis / ecological slope protection / stability

Author summay

李健宏(1984—), 男, 高级工程师, 副总经理, 学士, 从事工程项目管理及相关研究。E-mail: [e-mail]

基金资助

湖南省重点研发计划(2022SK2082)