基底侵蚀作用下泥石流动力过程分析
Numerical Study about the Influence of the Basal Erosional and Block Effectson Dynamic Process of Debris Dlow
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摘要: 基底侵蚀是运动物体与浅层地表在沿非滑动接触面剪切的时候而产生的相互作用，该作用可以改变泥石流系统的动力作用机制，从而影响泥石流的危害程度，是泥石流研究中的一项重要议题。本研究提出侵蚀率概念，分析了初始运动物质与夹带物质系统的侵蚀关系；同时建立了相关的数学模型和流变本构的数值实现，构建了数值模拟试验进行参数化评估。详细阐述了基底侵蚀作用对泥石流运动行为和整体流动性的影响。选取的流变模型和参数会产生比较好的模拟结果，侵蚀速率概念以及无量纲形式和动态模型的提出会给具有强烈侵蚀泥石流分析提供一套科学的潜在应用，也为地质灾害防治提供一定的技术参考。Abstract: The mechanism of mass changes and block in debris transportation process is an important topic in the study of fast landslides, debris flows and avalanches. Basal erosion is recognized as a dynamic interaction between the original moving material and the entrained basal topsoil sheared along their non-slip contact surface.The dam is used to control mobility behavior of debris flows, to decrease the runout speed of debris flows, to reduce erosion capability and discharge, and tomake the flow direction diverge.In this paper, a new concept of yield rate has been proposed, and the erosional relationship between original moving material and the entrained basal topsoil has been analyzed. Apertinent mathematical model and numerical implementation have been formulated. Parametric numerical experiments have been conducted to compare the erosional effects. The influence of involved erosive material and block effects on the runout behavior and global mobility of moving material has been elucidated. The simulated results are consistent with available experimental and field observations. The excellent match to the field data suggests that it is a plausible potential application to analyze the gravity-driven flow with significant erosion. The defined dimensionless form and the proposed yield rate can be estimated conveniently in general geotechnical practices.
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Key words:
- basal erosion /
- block dam /
- debris flow
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