基于根系构型定向调控的植物边坡固土机理研究

Plant slope is widely used in slope protection because of its advantages of water conservation, soil reinforcement, ecological restoration and strong sustainability. The configuration of roots in the soil has an impact on soil reinforcement and slope protection. However, it is restricted to develop and utilize the deep root plant to protect slope because the mechanism of root reinforcing soil is still unclear based on roots configuration. In this project, based on fractal theory and the root soil reinforcement theory, using the model tests, micro root window ecological monitoring system and numerical simulations, the root-soil interface friction and its variation law with root growth are researched. The high-strength root-soil structure model is built considering roots morphological characteristics. Applying the roots configuration control technology, the plant roots configuration is regulated and optimized. The method of directional controlling roots configuration is proposed to reinforce soil in the best way. Based on moisture migration theory, the moisture movement law in plant slope soil is resolved. The stability of plant slope is analyzed before and after the regulation of roots. The molding mechanism of high-strength root-soil structure is reveal in plant slope. The research results can effectively prevent and treat with shallow landslide and slope instability, which has vital important theoretical significance and practical value to the construction of ecological engineering and sustainable development.

植物护坡技术既可涵水固土，又可恢复生态环境，已广泛用于边坡防护等领域。植物根系的构型决定了其固土护坡的效果，然而基于根系构型的植物边坡根系固土机理研究还不够深入，限制了植物护坡技术在防治滑坡、崩塌等方面的应用。本项目基于分形理论、摩擦加筋等理论，利用模型槽试验、微根窗试验与数值模拟等手段，研究植物根系与土体间的界面力及其随根系生长的变化规律，构建考虑根系构型形态特征的高强度根-土结构模型；利用植物根系调控技术，优化根系构型，提出植物固土最佳根系构型的调控方法；基于植物水分迁移原理等理论，探明植物边坡根系区域内外水分运动的规律；数值分析根系调控前后植物边坡稳定性，揭示植物边坡高强度根-土结构体系成型机理。该项目研究成果可有效预防和治理浅层滑坡等地质灾害，对建设生态型工程和可持续发展具有较大的理论意义和实践价值。

植物边坡由于具有涵水固土、低成本、环境友好、可持续发展性、自修复再生能力和适应性强的特点，已广泛应用于工程实践。由于目前在植物根系构型、根系提高边坡土体抗剪强度等理论方面的研究相对于技术应用严重滞后，较大地制约了植物护坡技术在防治浅层滑坡、崩塌等方面的应用。本项目针对深根系植物香根草开展了试验和理论研究，解析了深根系植物香根草的根系形态参数随生长期的变化规律；建立了考虑根系空间分布角度的土体抗剪强度的关系表达式，阐明了不同分布形态的根系在浅层滑坡时发挥的不同力学作用，构建了考虑根系构型形态特征的高强度根-土结构模型；解析了植物边坡土体水分运动规律，建立了土壤体中湿润锋运移方程，构建了边坡土体基质吸力与含水率的V-G模型；推导出了考虑香根草根系分布角度对边坡安全系数的计算公式，并通过三轴试验验证了其可靠性。通过有限元强度折减法，研究了与剪切面呈不同的倾角根系对边坡浅层土体的应力、应变及稳定性的影响；数值分析根系调控前后植物边坡稳定性，揭示植物边坡高强度根-土结构体系成型机理。该项目研究成果可为预防和治理浅层滑坡等地质灾害提供思路。