Abstract Timely prediction of a landslide dam breach is particularly important for assessments of expected disaster consequences and to plan emergency responses. However, due to the complex composition and specific geotechnical properties of the landslide dam material, such a prediction is challenging. In this study, geological survey results and landslide dam breach mechanisms were used to develop a numerical model for overtopping-induced landslide dam breaches, considering variation of soil erodibility with depth. The model included a hydrodynamic process module, a soil erosion module, and a breach evolution module. Moreover, a time step iteration algorithm was adopted to simulate the soil and water coupling process during dam breach. A comparison of calculated and measured breach hydrographs, variations of dammed lake water level, breach sizes, as well as two other typical models were used to validate the rationality of the numerical model, by considering the Baige landslide breach case of November 3, 2018 with detailed measured data. Parameter sensitivity analysis showed that the soil erodibility coefficient exerted an important influence on the breach process, while soil critical shear stress had a relatively small influence (which remained within ±15% for output parameters when it was multiplied by 0.5, 1.0, and 2.0). Furthermore, spillway excavation was found to significantly reduce the peak breach flow if the dammed lake has a large storage capacity, thus identifying it as an effective measure for disaster mitigation.

中文翻译：

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滑坡坝漫顶破坏过程的预测

摘要 及时预测滑坡溃坝对于评估预期灾害后果和制定应急响应尤为重要。然而，由于滑坡坝材料的复杂组成和特定的岩土特性，这样的预测具有挑战性。在本研究中，考虑到土壤可蚀性随深度的变化，地质调查结果和滑坡溃坝机制被用于开发超顶引起的滑坡溃坝数值模型。该模型包括一个水动力过程模块、一​​个土壤侵蚀模块和一个裂口演化模块。此外，采用时间步长迭代算法来模拟溃坝期间的水土耦合过程。计算和测量的破坏水位线、堰塞湖水位变化、破坏大小、并结合2018年11月3日的白格滑坡溃决案例，结合详细实测数据，利用另外两个典型模型验证了数值模型的合理性。参数敏感性分析表明，土壤可蚀性系数对破坏过程有重要影响，而土壤临界剪应力影响较小（乘以0.5、1.0和2.0时输出参数保持在±15%以内） . 此外，发现如果堰塞湖具有大的蓄水能力，溢洪道开挖可以显着降低峰值破坏流量，从而将其确定为减灾的有效措施。2018 年有详细的测量数据。参数敏感性分析表明，土壤可蚀性系数对破坏过程有重要影响，而土壤临界剪应力影响较小（乘以0.5、1.0和2.0时输出参数保持在±15%以内） . 此外，如果堰塞湖的蓄水量大，则发现溢洪道开挖可以显着降低峰值破坏流量，从而将其确定为减灾的有效措施。2018 年有详细的测量数据。参数敏感性分析表明，土壤可蚀性系数对破坏过程有重要影响，而土壤临界剪应力影响较小（乘以0.5、1.0和2.0时输出参数保持在±15%以内） . 此外，如果堰塞湖的蓄水量大，则发现溢洪道开挖可以显着降低峰值破坏流量，从而将其确定为减灾的有效措施。