The headcut migration describes the physical process of breach side slope retreat that governs the widening of the breach. Modeling the growth of a breach due to embankment failure is the first step in mapping the resulting inundation in a floodplain. As removal of soil from the toe of the headcut effectively removes physical support for the upper part, the headcut fails on the plane normal to the direction of tensile stress. This process is a typical mode of tensile failure. A numerical model of the headcut migration was established by integrating the effects of the soil tensile strength, soil permeability and embankment geotechnical characteristics. Thus, a simple analytical equation was finally obtained to predict the critical length of the headcut. Furthermore, the presented model was verified by using the limit equilibrium method (LEM) for three typical embankment scales (2, 4 and 6 m high). The comparisons between the present model and the LEM show good agreements. The present model could provide a simple method to predict the critical length of the headcut migration and easily be adopted to breach widening models.

中文翻译：

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一种基于土体抗拉强度的断口边坡切头迁移模型

断头迁移描述了控制裂口扩大的裂口边坡撤退的物理过程。对因堤防破坏而导致的破坏增长进行建模是绘制洪泛区洪水泛滥的第一步。由于从切头的趾部去除土壤有效地去除了对上部的物理支撑，因此切头在垂直于拉伸应力方向的平面上失败。这个过程是典型的拉伸破坏模式。综合考虑土体抗拉强度、土体渗透性和路堤岩土特性的影响，建立了断头迁移的数值模型。因此，最终获得了一个简单的分析方程来预测切头的临界长度。此外，所提出的模型通过使用极限平衡法 (LEM) 对三个典型路堤尺度（2、4 和 6 m 高）进行验证。本模型与 LEM 之间的比较显示出良好的一致性。本模型可以提供一种简单的方法来预测切头偏移的临界长度，并且很容易被用于裂缝扩大模型。