偏转角度和颗粒级配对碎屑流前缘运动的影响

Study on influence of deflection angle and grain gradation of debris flow on mass-front motion parameters

为了研究碎屑流的运动物性,通过室内模型试验研究了不同偏转角度和颗粒级配对碎屑流运动参数的影响。研究结果表明:在偏转作用下,相同颗粒级配的碎屑流前缘速度的减小比例和能量的消耗随偏转角度的增大而增大;持速阶段的平均速度、运动距离及减速阶段的初始速度、运动距离均随偏转角度的增大呈抛物线变化特征;偏转角θ为20°时各运动参数指标最大;相同偏转角度下,岩土体的中值粒径越小,碎屑流的前缘物质受到的阻止效应越明显,持速阶段的平均速度、运动距离越小;减速阶段的运动距离与初始速度和底部摩擦效应有关。最后,提出了偏转作用下碎屑流的能量线模型。

The influences of deflection angle and grain gradation of debris flow on motion parameters are analyzed based on model test. The results show that as for the same grain gradation,the reduction ratio of front velocity of the debris flow and energy dissipation increase with the increase of internal friction angle. The average velocity and movement distance in velocity maintenance stage as well as the initial velocity and movement distance in deceleration stage all vary in a parabolic curve with the deflection angle and the parameters reach to the maximum value when the deflection angle is 20°. As for the same deflection angle,the mass-front of debris flow is subject to an increasing resistant effect with the decrease of medium diameter and also the average velocity and movement distance in velocity maintenance stage are in decrease. In deceleration stage,the movement distance is related to the initial velocity and the friction effect. Finally,the energy flow model of debris flow influenced by deflection is proposed.