土工离心机模拟泥石流问题的相似性考虑

尺度效应是阻碍对泥石流复杂动力学过程理解的最主要因素。土工离心机通过提供一个等效的高倍重力加速度场,能够在模型中还原岩土工程原型的应力状态,为泥石流物理模拟的尺度效应难题提供了一个经济可行的解决方案。在总结前人提出的两相流（泥石流）无量纲参数的基础上,建立了应用于土工离心机模拟泥石流的分层次相似性试验设计体系,可以确保模型和原型中泥石流运动学与动力学参数绝对值和相对值的一致,从而可以系统性地还原泥石流原型问题的物理过程。同时,针对对模拟结果产生较大影响的科里奥利效应和1g自然重力加速度,建议试验设计阶段选择有效旋转半径更大的离心机并适当降低旋转角速度。研究结果对泥石流和碎屑流的小尺度、大尺度物理模拟以及离心机模拟具有理论和技术层面的参考意义。

Scaling principles of debris flow modeling using geotechnical centrifuge

The scale effect of debris flow hinders the in-depth understanding of debris flow dynamics. The geotechnical centrifuge can replicate the appropriate stress states of the prototype through an equivalent elevated centrifugal acceleration field. The geotechnical centrifuge provides a cost-effective solution for the scale effect of physical modelling of debris flows. Based on the existing dimensionless group of two-phase flows, a hierarchical scaling solution is proposed for the design of debris flow experiments in the centrifuge. It ensures that both the absolute values (i.e., absolute stresses) and the relative values (characterized by the dimensionless group) in the model match those in the prototype, so that the fundamental physical processes in debris flows can be captured. Furthermore, the technical issues, the Coriolis effect and the influence of the real 1g gravitational acceleration, are quantitatively evaluated. To minimize these effects, a larger effective centrifuge radius and a lower angular velocity are recommended in the design of debris flow experiment using centrifuge. This study provides a significant theoretical and technical reference to the small-scale and large-scale physical modelling, and centrifuge modelling of debris flow problems.