Quantitative risk assessment for debris flows based on dynamic process:A case study of Huangniba gully,Muli County,Liangshan Prefecture,Sichuan Province
Quantitative risk assessment for debris flows based on dynamic process:A case study of Huangniba gully,Muli County,Liangshan Prefecture,Sichuan Province
王东坡 1董奇 1廖良波 2鲁帅 1闫帅星1
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作者信息
1. 成都理工大学地质灾害防治与地质环境保护国家重点实验室,成都 610059
2. 上海华测导航技术股份有限公司,上海 330046
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摘要
以四川凉山州木里县黄泥巴沟泥石流为例,基于Massflow数值仿真平台,通过现场调查及数值模型构建,分析泥石流形成演化机制,反演泥石流动力演进物理过程.在此基础上,开展不同重现期泥石流危险性评估,构建不同破坏模式下砌体结构易损性评估模型,建立基于动力过程的泥石流风险评估方法.研究区泥石流风险评估结果表明:20 a 一遇泥石流极高、高风险区面积分别为0.15×104和1.68×104 m2,其中建筑物数量分别为10和13座;50a一遇极高、高风险区面积相比20 a一遇分别增加40％和70.8％,建筑物分别增加2和4座;100a一遇极高、高风险区面积相比20 a 一遇分别增加113.3％和132.1％,建筑物分别增加11和5座.本研究构建的考虑侵蚀的泥石流动力过程数值模型可较好反映黄泥巴沟泥石流事件,且砌体结构易损性评估模型经与其他泥石流事件分析验证表明其具有较好的可行性,相关结果可为黄泥巴沟泥石流风险定量预测提供依据.
Abstract
[Objective,Methods]This study focus on debris flows in Huangniba gully,Muli County,Liangshan Prefecture,Sichuan Province,utilizing a mass flow numerical simulation platform.Through field investigations and the construction of numerical models,we analyze the mechanisms driving debris flow formation and evolution,ai-ming to invert these mechanisms.Based on this foundation,we assess debris flow hazards,develop a vulnerability model for masonry structures under different damage modes,and establish a dynamic process-based debris flow risk assessment method.[Results]The risk assessment indicates that,for a 20-year return period,very high-and high-risk zones for debris flow encompass 0.15×104 m2 and 1.68×104 m2,affecting 10 and 13 buildings,respectively.For a 50-year return period,the areas of very high-and high-risk zones expand by 40％and 70.8％,with 2 and 4 additional buildings affected.Moreover,for a 100-year return period,these zones increase by 113.3％and 132.1％,respectively,affecting 11 and 5 more buildings compared to the 20-year scenario.[Conclusion]Further-more,the erosion-incorporating debris flow dynamics model developed in this study accurately represents the debris flow events in Huangniba gully.Additionally,the vulnerability assessment model for masonry structures was valida-ted against other debris flow events,confirming its enhanced feasibility.These findings provide a foundation for quantitative risk prediction in Huangniba gully.
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