康定市牛棚子沟泥石流发育特征及动力学过程模拟

Development Characteristics and Dynamical Process Simulation of Niupengzi Debris Flow in Kangding

牛棚子沟位于四川省康定市大渡河左岸,沟口为土地复垦区,2020年8月暴发泥石流。经现场勘察,牛棚子沟流域内物源丰富,沟口排导条件极差,仍具备暴发大规模泥石流的可能性。笔者采用规范公式计算了牛棚子沟泥石流的动力学参数,分析了泥石流的成灾特征。使用基于有限体积法的CFX软件,模拟了牛棚子沟可能暴发的泥石流在沟口的运动、堆积过程。模拟结果显示20 a一遇降雨泥石流堆积面积为1.70×10^(4)m^(2),最大堆积宽度为250 m,沟口居民将遭受重大威胁,既有排导槽设计不合理。将模拟结果与实测堆积范围对比,计算得出模拟结果精度为88.3%,并根据模拟结果提出了针对性的防治措施建议。

Niupengzi debris flow gully is located in the left shore of Dadu River,Kangding City,Sichuan Province.The reclamation area is located in the mouth of the gully.The debris flow broke out in August 2020.According to the in-site investigation,there were abundant material source in Niupengzi gully.The diversion condition of the gully mouth was very poor,and there was still possibility of large-scale debris flow.In this paper,the kinematic parameters of debris flow were calculated and analyzed by using the code-recommended formulae,and the disaster characteristics of the debris flow were analyzed.The CFX software based on the finite volume method was used to simulate the movement and accumulation process of Niupengzi debris flow.The simulation results show that the accumulation area of debris flow with a frequency of 20 years was 17000 m^(2),and the maximum accumulation width was 250 m.The residents in the gully mouth were under great threat,and the design of existing diversion channel is unreasonable.By comparing the simulation results with the insite measured accumulation range,the accuracy of the simulation results is 88.3%.The specific prevention and treatment measures are proposed according to the simulation results.