中文摘要：

从粒子尺寸阶段和内在的表面的联合行动的小粒的流动结果的集体前面的速度。然而，因为磨擦的复杂性，在流动运动，象斜坡脚趾阻抗效果那样的细节和动量转移机制期间有不是完全由理论分析，数字模拟，或地调查解释了。到干燥小粒的流动的集体前面的速度由斜坡的角度影响了到刺杀的学习，飞机和粒子缩放我们进行了的阶段记录了快速、长刺杀的岩石崩落或雪崩的运动的模型实验。斜槽测试用 25 漠 ? 桴 ? 湥牥祧搠獩楳慰楴湯猠牴 ' 壮肭玫男逼陆嵌缺唤小?

英文摘要：

The mass-front velocities of granular flows results from the joint action of particle size gradations and the underlying surfaces. However, because of the complexity of friction during flow movement, details such as the slope-toe impedance effects and momentum-transfer mechanisms have not been completely explained by theoretical analyses, numerical simulations, or field investigations. To study the mass-front velocity of dry granular flows influenced by the angle of the slope to the runout plane and particle size gradations we conducted model experiments that recorded the motion of rapid and long-runout rockslides or avalanches. Flume tests were conducted using slope angles of 25°, 35°, 45°, and 55° and three particle size gradations. The resulting mass-front motions consisted of three stages acceleration, velocity maintenance, and deceleration. The existing methods of velocity prediction could not explain the slowing effect of the slope toe or the momentum-transfer steady velocity stage. When the slope angle increased from 25° to 55°, the mass-front velocities dropped significantly to between 44.4% and 59.6% of the peak velocities and energy losses increased from 69.1% to 83.7% of the initial, respectively. The velocity maintenance stages occurred after the slope-toe and mass-front velocity fluctuations. During this stage, travel distances increased as the angles increased, but the average velocity was greatest at 45°. At a slope angle of 45°, as the median particle size increased, energy loss around the slope toe decreased, the efficiency of momentum transfer increased, and the distance of the velocity maintenance stage increased. We presented an improved average velocity formula for granular flow and a geometrical model of the energy along the flow line.