Abstract Retrogressive spreading failure occur frequently in sensitive clay deposits due to triggering such as gradual natural erosion and degradation or artificial cut. The large scale of failure observed in retrogressive landslides have been attributed to quasi-horizontal shear band propagation along a weak layer. This study explores the critical conditions for such failure and develops the criteria for catastrophic propagation of quasi-horizontal shear band in infinite slopes accounting for unidirectional uphill shear band propagation and removal of downslope support. The critical conditions and criteria, with respect to pre-existing softened zone length and gravity shear stress ratio, for catastrophic shear band propagation in cut slopes are influenced by the front angle of cut slope, the softened zone length and the post-peak degradation relationship. The proposed criteria are justified by a large deformation finite element analysis. A framework for stability analysis of cut slopes in sensitive clays is established based on the criteria for catastrophic shear band propagation. The 1994 Sanite-Monique landslide in Quebec Canada is re-visited using the proposed framework, with the calculated factor of safety and failure mechanism compared with an upper bound limit analysis.

中文翻译：

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剪切带沿弱层传播的削坡稳定性分析

摘要 在敏感的粘土矿床中，由于逐渐的自然侵蚀退化或人工切割等触发，倒退蔓延失败经常发生。在倒退滑坡中观察到的大规模破坏归因于沿弱层的准水平剪切带传播。本研究探讨了这种破坏的临界条件，并制定了无限边坡准水平剪切带灾难性传播的标准，考虑了单向上坡剪切带传播和下坡支撑的移除。临界条件和标准，关于预先存在的软化区长度和重力剪应力比，在切割边坡中灾难性剪切带传播的临界条件和标准受切割边坡前角的影响，软化区长度与峰后降解关系。提出的标准通过大变形有限元分析证明是合理的。基于灾难性剪切带传播的标准，建立了敏感粘土切割边坡稳定性分析框架。1994 年加拿大魁北克的 Sanite-Monique 滑坡使用提议的框架重新访问，计算的安全系数和失效机制与上限分析进行了比较。