Abstract
The mountainous areas of Southwest China are characterized by steep terrain, deeply incised valleys, and complex geological structures. Debris flows, as the primary type of geological hazard in this region, severely restrict regional economic development due to their typical characteristics of beyond-frequency occurrence, ultra-high dynamic damage, and complex dynamic movement processes. Based on the OpenLISEM numerical simulation platform and incorporating rainfall, topographic, and material source parameters from Chutou Gully and Sucun Gully in Wenchuan County, this study conducts numerical simulation of the entire process of debris flow initiation, movement, and deposition to back-analyze the August 20 debris flow event in Chutou Gully and the July 10 debris flow event in Sucun Gully. Key parameters such as flow velocity, flow depth, and deposition range were obtained, and model settings and relevant parameters were dynamically calibrated based on actual data. The simulation accuracy index Ω values reached 1.57 and 1.37 respectively, indicating that the simulation results are in good agreement with observed data. Furthermore, the dynamic damage processes of debris flows under check dam service conditions in Chutou Gully and Sucun Gully were predicted for rainfall frequencies of 5%, 2%, and 1%, providing reasonable recommendations for future disaster prevention and mitigation efforts. This study reveals the dynamic evolution laws and complete movement processes of debris flows in Southwest mountainous areas under check dam constraints, and the research content and related methods can provide data support and theoretical reference for conducting predictive research on similar debris flows in the region.
Full Text
Study on the Typical Debris Flow Damage Process under Check Dam Service in Southwest Mountainous Areas
Luo Chaopeng¹, Kang Yongchuang¹
¹ Guiyang Survey Design and Research Institute of Chinese Electric Power Construction Group Co., Ltd., Guiyang 550081
Abstract
The southwestern mountainous regions of China feature steep topography, deeply incised river valleys, and complex geological structures. Debris flows represent the predominant geological hazard in these areas, characterized by their tendency to exceed design frequencies, inflict severe dynamic damage, and exhibit highly complex kinematic processes—factors that significantly impede regional economic development. This study utilizes the OpenLISEM numerical simulation platform, incorporating rainfall, topographic, and source material parameters from Hutou Gully and Sucun Gully in Wenchuan County. Through comprehensive numerical modeling of the complete debris flow cycle—including initiation, transport, and deposition—we back-calculated the August 20 (Hutou Gully) and July 10 (Sucun Gully) debris flow events. Key parameters such as flow velocity, flow depth, and deposition extent were extracted, and model configurations were dynamically refined using observational data. The simulation accuracy index (Ω) values of 1.57 and 1.37, respectively, indicate strong agreement between simulated results and field observations. Additionally, we forecast the dynamic damage processes of debris flows under check dam operation scenarios for rainfall frequencies of 5%, 2%, and 1%, offering evidence-based recommendations for future disaster prevention and mitigation strategies. This research elucidates the dynamic evolution patterns and complete kinematic processes of debris flows in southwestern mountainous areas under check dam constraints, providing both data support and methodological framework for predictive studies of analogous debris flow events in the region.
Keywords: debris flow; check dam; OpenLISEM; numerical simulation; dynamic damage