岩体的初始损伤对爆破效果的影响研究

根据损伤力学理论，提出了含初始损伤岩体动态损伤本构模型。结合Grady根据破碎能量守则给出的脆性材料动态平均块度尺寸公式，将初始损伤变量引入计算模型，并充分考虑爆炸应力波对岩体的破碎作用和在爆生气体膨胀及渗流压力作用下岩块之间的相互挤压碰撞作用，得出了爆破后的平均块度计算式，同时进行了试验验证。计算和试验结果表明，岩体的初始损伤对爆破效果的影响是非常显著的，但是可以通过改变爆破设计参数控制并利用初始损伤以改善爆破效果。同时还得出了一些有益的结论，对指导工程实践具有一定参考价值。

INFLUENCE OF ORIGINAL DAMAGES IN ROCKMASS ON BLASTING EFFECT

According to the damage mechanics, the dynamic damage constitutive model of rock mass containing original damages is proposed. The formula of the average fragment size containing original damage variable after blasting is derived from the dynamic average fragmentation size formula of the fragile material given by Grady on the basis of fragmentation energy rules, fully considering the breaking action of the explosion stress wave and the motive fragment blocks extrusion and collision under the action of the detonation gas expansion and infiltration flow pressure. The experiment being made by our research group is aimed at verifying the results of the constitutive model. The results of the experiment coincide well with the calculation. The studies show that the influence of the original damages in the rock mass on blasting effect is very remarkable, and the average fragment size increase with the increasing of original damages. But the original damages can be controlled and utilized by modifying design parameters of blasting so as to improve the blasting effect. Some beneficial conclusions are summarized which are available for reference to practical projects.