山地灾害与地表过程重点实验室知识库

基于Hertz弹性碰撞理论的修正公式是计算泥石流块石冲击力的有效方法之一,但公式中的修正系数目前尚无具体的量化方法。在Hertz接触理论和Thornton弹塑性假设的基础上,建立了泥石流块石冲击构筑物的计算模型,推导了修正系数的表达式。研究表明,修正系数是材料强度、泥石流块石尺寸和速度的函数而非一个常量,其随泥石流块石冲击速度的增加而减小,随泥石流块石半径、构筑物材料强度的增加而增加。板子沟泥石流沟防治工程计算结果显示,修正冲击力仅为Hertz弹性碰撞冲击力的15.58%。当泥石流块石冲击速度小于3 m/s,修正系数大于0.20;当泥石流块石冲击速度大于3 m/s,修正系数介于0.10~0.20,计算结果与实践估计较为一致。 更多还原
 

Modified formula based on the Hertz elastic collision theory is one of the effective methods to calculate impact force exerted by boulders transported (IFEBT) in debris flow. However, there is no informative method to quantify the modified coefficient currently. A calculation model of IFEBT was built and the analytical equation of the modified coefficient was deduced based on the Hertz contact theory and the Thornton elastoplasticity hypothesis. The study shows that the modified coefficient is a function of material strength, boulder size, and velocity rather than constant. The IFEBT decreases with the growth of boulder velocity and increases with structure material strength and boulder size. The modified method was applied to control engineering for Ban Zigou debris flow. Calculation results show that the modified IFEBT in debris flow is only 15.58% of the one by the Hertz elastic theory. The modified coefficient is larger than 0.2 when boulder velocity is less than 3 m/s and ranges between 0.1 and 0.2 when boulder velocity is larger than 3 m/s.