摘要
泥石流运动阻力是泥石流动力学的核心问题。泥石流内部多种流变类型和应力过程并存,目前各类阻力模型难以准确描述其运动阻力。本文基于原位监测与数值模拟方法,针对宾汉模型、湍屈模型、Voellmy模型、膨胀塑流模型四种不同的阻力模型,分析粘性泥石流龙头形态特征与阻力模型的适用性;基于Euler(时间过程线)和Lagrange(空间过程线)两种视角,将数值计算结果与蒋家沟实测粘性泥石流龙头形态数据进行比较;进一步改变粘性泥石流的密度和底床坡降,分析四种阻力模型计算结果对这两个基本参数的敏感性。结果表明:(1)综合考虑了固液两相混合流屈服摩阻、粘性应力和分散应力的膨胀塑流模型适用于描述粘性泥石流的运动阻力。(2)宾汉模型计算结果与实测数据相差较大,而膨胀塑流模型计算结果并未随密度变化产生差异,但受坡度影响较大,与实测数据较为吻合;湍屈模型、Voellmy模型计算得到的速度几乎不受坡降变化影响,与实际泥石流不符,初步分析可能与湍流阻力项中残留层的计算受坡降影响有关。本文可为泥石流灾害风险评估和防治工程设计过程中的阻力模型选取提供参考。
To measure the resistance of a flowing debris flow to movement is the key issue of debris flow dynamics.A variety of rheological formations and stresses coexist in a flowing debris flow;there was no dynamic resistance model available to properly describe debris flow movement.In this study,it conducted in-situ monitoring and numerical simulation to investigate the morphological features of viscous debris flow head and the applicability of four dynamic resistance models by introducing Bingham model,Turbulence-yield model,Voellmy model and Dilatant Plastic model into experiments,separately.From the perspective of both Euler(time process line)and Lagrange(spatial process line)coordinate systems,morphological values of viscous debris flows obtained by simulations were verified by observations at a well-known high prevalence area of debris flow,Jiangjia Gully,Yunan,China.Then it analyzed the sensitivity of two parameters,the density of viscous debris flow and gully bed slope,in the four dynamic resistance models by adjusting their preset values in the models.Following result are obtained:(1)The dilatant plastic model,which integrated yield friction,viscous stress and dispersion stress of solid-liquid mixed flow,was suitable for describing the movement resistance of viscous debris flow.(2)There was a large discrepancy between the mathematical results from Bingham model and observations at Jiangjia Gully.The modelling by dilatant plastic model was justified by observations,in which simulation was not changed in values with the changes of the density of viscous debris flow,but it was altered by varied slopes.The velocities of debris flow calculated by Turbulence-yield model and Voellmy model kept steady as bed slope was reset in the model,which were inconsistent with general knowledge;this might be referred to the interference of bed slope in the calculation of residual layer in the turbulent resistance term of the model.This paper can provide a reference for risk assessment of debris flow disaster and the selection of resistance model in the design of control engineering.
作者
李彦稷
李浦
胡凯衡
LI Yanji;LI Pu;HU Kaiheng(Chengdu Institute of Mountain Hazards and Environment,Chinese Academy of Sciences&Ministry of Water Resources,Chengdu 610299,China;University of Chinese Academy of Sciences,Beijing 100049,China)
出处
《山地学报》
CSCD
北大核心
2023年第2期216-227,共12页
Mountain Research
基金
国家自然科学基金项目(41371039
91747207)
中国国家铁路集团有限公司科技研究开发计划课题(K2019G006)
陕西省自然科学基金青年基金项目(2021JQ-452)~~。
