摘要
冲击气浪是雪崩最为常见的链生灾害,其具有超强破坏力和超大致灾范围,可对雪崩流动堆积外的区域造成严重威胁。目前,针对雪崩-冲击气浪致灾强度的定量预测方法仍十分欠缺。本文基于深度积分和双层流理论,考虑雪崩-冲击气浪层间质量/动量传递、冲击气浪空气卷吸、四周扩散和受阻减速等关键物理过程,建立了雪崩-冲击气浪高效动力学模型。结合灾害现场调查和数值仿真,重构了瑞士阿尔卑斯山区Innerchinn雪崩-冲击气浪演进过程,探究了雪崩-冲击气浪动力致灾机制。结果表明:Innerchinn雪崩启动体积为9×10^(4)m^(3),运动距离达2700m,其运动过程中产生了强烈的冲击气浪,沟谷两侧冲击气浪最大速度超40m·s^(-1),最大压强达5.5kPa,摧毁了大量植被。冲击气浪高速、高压区集中于沟谷转折处,当雪崩运动方向偏转时,冲击气浪可脱离雪崩主体运动致灾。此外,相较于雪崩主体,冲击气浪表现出更大的传播距离和影响高度,地面以上15m范围内强度超12级台风,裹挟的冰雪碎屑使得冲击气浪在同等速度下,相较于台风表现出更强的破坏力。本文研究成果可为高寒山区雪崩-冲击气浪灾害风险防控提供理论与技术支撑。
Avalanche-induced air blasts represent one of the most frequent and destructive cascading effects of snow avalanches.Characterized by intense destructive force and extensive impact ranges,they can inflict severe damage well beyond the boundaries of the avalanche itself.Nevertheless,reliable methods for evaluating their destructive potential remain limited.This study develops a depth-averaged two-layer model to simulate avalanche-triggered air blasts,incorporating essential physical processes such as mass and momentum transfer,air entrainment,lateral spreading,and cloud drag.By integrating field investigations with numerical simulations,we reconstructed the evolution of the Innerchinn avalanche and the associated air blast events.Results show that the avalanche originated with a volume of 9×10^(4)m^(3)and traveled a total distance of 2700 m.During its descent,it generated intense air blasts with peak velocities exceeding 40m·s^(-1)and maximum pressures reaching 5.5 kPa,resulting in extensive forest destruction.The most powerful air blast occurred at a bend in the valley,where the flow direction of the avalanche core shifted abruptly,leading to the separation and independent propagation of the air blast.Compared to the avalanche core,air blasts exhibited significantly larger impact areas both horizontally and vertically.In the case of the Innerchinn avalanche,the air blast maintained destructive force up to 15 m above ground level,equivalent to a Force 12 wind load.The mixture of ice crystals and snow dust increased the density and destructive potential of the air blast,rendering it more damaging than a typhoon at comparable wind speeds.This study provides theoretical and technical support for assessing snow avalanche-air blast risks in high-mountain regions.
作者
庄宇
邢爱国
陈仁朋
ZHUANG Yu;XING Aiguo;CHEN Renpeng(College of Civil Engineering,Hunan University,Changsha 410082,China;Key Laboratory of Building Safety and Energy Efficiency of Ministry of Education,Hunan University,Changsha 410082,China;Hunan Provincial Engineering Research Center of Advanced Technology and Intelligent Equipment for Underground Space Development,Changsha 410082,China;WSL Institute for Snow and Avalanche Research SLF,Davos Dorf 7260,Switzerland;State Key Laboratory of Ocean Engineering,Shanghai Jiao Tong University,Shanghai 200240,China)
出处
《工程地质学报》
北大核心
2025年第6期2257-2265,共9页
Journal of Engineering Geology
基金
国家自然科学基金项目(资助号:42277126,51878267).
关键词
雪崩
冲击气浪
动力致灾
形成与传播机制
数值模型
Snow avalanche
Air blast
Dynamic mechanism
Formation and propagation
Numerical model
