Objective The development characteristics of the debris flow in Nangang gully, Fangshan District, Beijing City were analyzed to reveal the differences in material source composition and disaster-causing mechanisms of rainstorm-induced debris flow in the southwest mountainous areas of Beijing City, in order to provide theoretical support for debris flow prevention and control in the local area fand similar regions. Methods Taking the debris flow disaster that occurred in Nangang gully after the ‘23·7’ rainstorm in Beijing as the research object, topographic data were acquired using unmanned aerial vehicle (UAV), and terrain, material source, and water source conditions were analyzed in combination with field investigations. The FLO-2D model was used to simulate the dynamic process of the debris flow, with a focus on quantifying movement parameters under the dendritic gully-high and steep slope topography. The results were then validated against field investigation data. Results Nangang gully featured large topographic relief and deeply incised valleys, with abundant and diverse material sources (including landslide deposits, slope erosion deposits, and channel deposits). Atmospheric precipitation served as the main water source, and rainstorms were the primary triggering factor for debris flow. The FLO-2D simulations showed that the maximum sliding velocity of the debris flow was 6.75 m/s, and the maximum accumulation depth was 14.6 m. The error rate between the simulation and field investigation results was 3.995%, which was within a reasonable range. A comprehensive analysis confirmed that the susceptibility index of debris flow in Nangang gully was 2—3, classifying it as a debris flow-prone gully. Conclusion The Nangang gully debris flow is a typical rainstorm-induced gully-type dilute debris flow, with its formation following the process of ‘rainfall infiltration—runoff concentration—channel bed scouring—material convergence’, and the gully is classified as a debris flow-prone area. The FLO-2D simulation has been verified to be reliable.
文献参数: 赵云辉, 马海志, 柳文涛, 等.北京市南港沟泥石流发育特征及孕灾成因[J].水土保持通报,2025,45(6):132-139. Citation:Zhao Yunhui, Ma Haizhi, Liu Wentao, et al. Developmental characteristics and disaster-causing mechanisms of debris flow at Nangang gully, Beijing City [J]. Bulletin of Soil and Water Conservation,2025,45(6):132-139.
WangGaofeng, YangQiang, ChenZongliang, et al. Risk assessment of debris flow in the Ganjia gully of the Bailongjiang Basin [J]. Journal of Sediment Research, 2020,45(4):66-73.
JiangTaotao. Study on risk assessment and early warning model of debris flow in Shijiaying Township, Beijing [D]. Beijing:China University of Geosciences, 2021.
ShiXuelei, HanXudong, YangXiuyuan, et al. Factors inducing the Xigouwan landslide in the Three Gorges reservoir area and the influence of antecedent precipitation [J]. Journal of Geomechanics, 2023,29(2):253-263.
WangRuijun, WangShuaidong, SunYongbin, et al. Study on the distribution law and evolution trend of debris flow hazards in Yanqing, Beijing [J]. World Nuclear Geoscience, 2024,41(3):623-632.
MaJunxue, GaoHuiran, XuChong. Characteristics of flash flood-debris flow disaster induced by the ‘23·7’ rainstorm in Hantai village, Changping District, Beijing [J]. Water Resources and Hydropower Engineering, 2024,55(7):1-18.
ChangMing, XuQiang, WangYunsheng, et al. Development characteristics and disaster-causing mechanisms of the “8 · 3” catastrophic flash flood and debris flow in Guzan, Kangding, Sichuan Province [J]. Geomatics and Information Science of Wuhan University, 2024,49(11):2136-2144.
MaZhiliang, ZhuangJianqi, WuJing, et al. Characteristics analysis and risk assessment of low-frequency debris flow induced by heavy rainfall based on numerical simulation: A case study of Jiwozi flash flood and debris flow in Qinling Mountains [J]. Bulletin of Soil and Water Conservation, 2025,45(1):147-157.
LiuFuzhen, ZhangHaowei, XiaoDongsheng. Risk assessment of highway debris flow in Jiedigang village based on FLO-2D numerical simulation [J]. Science Technology and Engineering, 2022, 22(13): 5417-5424.
LiBaoxing, CaiQiang, SongJun, et al. Risk assessment of debris flow hazard based on FLO-2D:A case study of debris flow in Maiduo gully [J]. Journal of Natural Disasters, 2022,31(4):256-265.
QuJingkai, YangWeimin, ShenJunfeng, et al. Analysis of debris flow engineering treatment effect based on DEM data preprocessing in small watershed:A case study of Fangjiagou debris flow, Zhangxian County [J]. Hydrogeology & Engineering Geology, 2024,51(4):206-219.
ZhaoMan, SunJun, ZhuKaiyue. Simulation prediction and risk evaluation of debris flow in gullyprone ditches of Lajing village, Lanping County, Yunnan Province, China [J]. The Chinese Journal of Geological Hazard and Control, 2024,35(5):110-119.
HuangXun, TangChuan, ZhouWei. Numerical simulation of occurrence frequency estimation model for debris flows [J]. Journal of Engineering Geology, 2014,22(6):1271-1278.
FangQunsheng, TangChuan, WangYi, et al. A calculation method for predicting dynamic reserve and the total amount of material source of the debris flows in the Wenchuan meizoseismal area [J]. Journal of Disaster Prevention and Mitigation Engineering, 2016,36(6):1008-1014.
China Association of Geological Hazard Prevention Engineering. Specification of Geological Investigation for Debris Flow Stabilization: T/CA GHP 006—2018 [S]. Wuhan: China University of Geosciences Press, 2018.
LiaoLiye, ZengQingli, YuanGuangxiang. Characteristics and mechanism of the rainstorm-induced debris flow on July 16 in Huairou, Beijing [J]. Journal of Engineering Geology, 2021,29(3):807-816.
TangDesheng, TangChuan, ZhuJing. Outbreak probability analysis of gully debris flow in Wenchuan earthquake zone [J]. Water Resources and Power, 2015,33(9):148-151.
LiangHongxi, ShangMin, XuXin. Research on the influencing factors of flow and deposition of debris flow based on the FLO-2D simulation[J]. Journal of Engineering Geology, 2016, 24(2): 228-234.