Understanding mechanical interactions at the root-soil interface is essential to predict the erosion of vegetated slopes. Recently, the shear strength of vegetatedil under changing hydraulic conditions has been measured and modeled; however, root-soil interfaces have not been investigated under changing hydraulic conditions. This paper proposes (1) a novel pullout apparatus to measure the shear strength at the root-soil interface under changing suction, (2) a Mohr-Coulomb-Vilar (MCV) shear strength model of root-soil interfaces, and (3) a numerical simulation using Node-To-Segment (NTS) approach along with Finite Element Method (FEM). The pullout tests were verified using the numerical simulation, and the results showed that the combination of the MCV model and NTS/FEM approach can accurately predict the shear behavior of root-soil interfaces under changing suction. In addition, we experimentally evaluated the pullout problem of roots and showed that the present method provides reasonably predicts root-pullout problems even when the suction is changed during the pullout process. The current method, therefore, can be used for predicting root-soil interface dynamics under varying suction and soil pressure by only adding two additional parameters of the Vilar model.

了解根部-土壤界面的机械相互作用对于预测植被坡度的侵蚀至关重要。最近，在变化的水力条件下，vegetatedil 的剪切强度已被测量和建模；然而，尚未在不断变化的水力条件下研究根-土界面。本文提出 (1) 一种新型拉出装置，用于测量吸力变化下根-土界面的剪切强度，(2) 根-土界面的莫尔-库仑-维拉 (MCV) 剪切强度模型，以及 (3)使用节点到段 (NTS) 方法和有限元方法 (FEM) 进行数值模拟。使用数值模拟验证了拉拔试验，结果表明，MCV模型与NTS/FEM方法的结合可以准确预测吸力变化下根土界面的剪切行为。此外，我们通过实验评估了根部拔出问题，并表明即使在拔出过程中吸力发生变化时，本方法也可以合理地预测根部拔出问题。因此，目前的方法可用于预测在变化的吸力和土壤压力下根 - 土壤界面动力学，只需添加 Vilar 模型的两个附加参数。