Abstract

While excavated discharge channels are often used for the emergency treatment of landslide-dammed lakes, the erosion of the discharge channel of a landslide dam is complex and rarely monitored on site. This work presents a quantitative monitoring method based on three-dimensional terrestrial laser scanning technology (TLS) for analyzing the erosion of a landslide dam discharge channel and then applies this method to evaluate the emergency engineering treatment of the 2018 Baige landslide-dammed lake in 2019. The proposed method uses TLS technology to accurately track the dynamic evolution of the discharge channel and to quantify the lateral erosion. Moreover, qualitatively analysis for vertical erosion is conducted based on the difference between actual and hypothetic river elevation. The results indicate that erosion processes of landslide deposition fluctuate as the results of flow discharge variations. Damage to the covering layer consisting of large particles is considered to be the main cause of this phenomenon. According to the relationship between erosion intensity (EI) and flow velocity, an empirical formula is deduced for erosion analysis. The key parameter in this formula is determined by the variation rate of discharge, the flow velocity, the composition of riverbank and the flow field distribution.

摘要

虽然开挖泄洪道常用于滑坡堰塞湖的应急处理，但滑坡坝泄洪道的侵蚀情况复杂，现场监测很少。本文提出了一种基于三维地面激光扫描技术（TLS）的定量监测方法，用于分析滑坡坝泄洪道侵蚀情况，并将该方法应用于2018年白格滑坡坝湖2019年应急工程处理评价。所提出的方法使用TLS技术准确跟踪放电通道的动态演化并量化侧蚀。此外，根据实际和假设河流高程的差异，对垂直侵蚀进行了定性分析。结果表明，由于流量变化，滑坡沉积的侵蚀过程会发生波动。由大颗粒组成的覆盖层的损坏被认为是这种现象的主要原因。根据侵蚀强度之间的关系（EI ) 和流速，推导出侵蚀分析的经验公式。该公式中的关键参数由流量变化率、流速、河岸组成和流场分布决定。