Abstract Bio-engineered slopes use vegetation as “live” protection elements against the triggering forces of landslides, erosions and debris flows. In this paper, the effects of basic plant traits (both root and shoot) on their slope stability functions in compacted and planned green slopes have been reviewed. This review is based on over 200 papers on areas primarily related to unsaturated soil mechanics, plant biology, hydrology and ecology. The first section of this paper gives an overview of the plant-soil-water continuum, highlighting the key interactions that determine reinforcing actions of vegetation in sloped soil. The hydraulic pathway (water flow from roots to atmosphere) and plant response at varying soil stress (suction) is explained. Thereafter, the effects of inherent plant properties (bio-polymer composition, plant physiological parameters and root morphology) on soil reinforcement are discussed. The second section discusses the three stability functions (i.e., mechanical, hydrological and interception reinforcements) of vegetation in slopes, wherein the first two subsections considering mechanical and hydrological reinforcement action are catalogued. In the third subsection, the interception functions of plant (both shoot and root parameters) against erosion and debris flow are illustrated based on experimental, numerical and field observations. In the last section, the knowledge gaps on the topic of bio-engineered slope stability are highlighted such as the consideration of plant age effect, plantation strategy and high suction response of vegetation. The possible negative effects of vegetation towards slope stability resulting from extreme climate conditions such as extended droughts, forest fires, freeze-thaw cycles and elevated CO2 concentration levels are discussed. The review identifies new research themes for developing futuristic bio-engineered slopes. The potential of real time monitoring and maintenance of bio-engineered slopes, redefinition of wilting point and concept of “plant sensors” are also put forth.

中文翻译：

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生物工程边坡植被性状及其稳定性功能的影响：透视回顾

摘要 生物工程斜坡利用植被作为“活”保护元素，抵御滑坡、侵蚀和泥石流的触发力。本文综述了植物基本性状（包括根系和枝条）对其在压实和规划绿化边坡中的边坡稳定性功能的影响。本综述基于 200 多篇主要与非饱和土力学、植物生物学、水文学和生态学相关领域的论文。本文的第一部分概述了植物-土壤-水连续体，重点介绍了决定倾斜土壤中植被加固作用的关键相互作用。解释了水力途径（水从根部流向大气）和植物在不同土壤压力（吸力）下的反应。此后，植物固有特性的影响（生物聚合物成分，讨论了植物生理参数和根系形态）对土壤加固的影响。第二部分讨论了边坡植被的三个稳定性函数（即机械、水文和截留加固），其中前两个小节考虑了机械和水文加固作用。在第三小节中，根据实验、数值和现场观察，说明了植物（地上部和根参数）对侵蚀和泥石流的拦截功能。在最后一节中，强调了生物工程边坡稳定性主题的知识空白，例如考虑植物年龄效应、种植策略和植被的高吸力响应。讨论了极端气候条件（如长期干旱、森林火灾、冻融循环和 CO2 浓度水平升高）导致的植被对斜坡稳定性可能产生的负面影响。该评论确定了开发未来生物工程斜坡的新研究主题。还提出了实时监测和维护生物工程斜坡的潜力，重新定义枯萎点和“植物传感器”的概念。