累积效应下初支混凝土爆破损伤规律研究

Research on blasting damage law of initial concrete support under cumulative effect

为研究初支混凝土在循环爆破荷载作用下爆破损伤的累积效应,通过引入等效距离和等效药量的概念,代替爆心距和最大段药量对萨道夫斯基经验公式拟合得到质点峰值振速的衰减公式,根据爆破损伤经典公式,推导了爆破损伤增量公式。通过分析质点峰值振速和损伤增量随爆破次数和等效距离变化的关系,得到了初支混凝土在循环爆破荷载作用下的爆破累积损伤规律。研究结果表明:累积损伤随爆破次数增加而增大,但损伤增量却逐渐减小,两者变化皆呈现出非线性关系;临近爆源的几组测点在经过循环爆破后初支混凝土的累积损伤已达到损伤界限;损伤增量随等效距离变化的关系与质点峰值振速衰减规律具有相似性,且两者具有较高线性相关性。

In order to study the cumulative effect of blasting damage of initial concrete support under cyclic blasting load,the concepts of equivalent distance and equivalent charge were introduced to replace the blasting center distance and maximum charge to fit the Sadowski empirical formula to get the attenuation formula of peak particle velocity(PPV).Based on the classic formula of blasting damage,a blasting damage increment formula is proposed.By analyzing the relationship of PPV and damage increment with blasting times and effective distance change,the blasting cumulative damage law of the initial concrete support under the cyclic blasting load is obtained.The research results show that the cumulative damage increases with the increase of blasting times,but the damage increment gradually decreases,both showing a nonlinear relationship.The cumulative damage of the initial concrete support of several sets of measuring points near the blasting source under cyclic blasting has reached the damage limit.The relationship between the damage increment and the equivalent distance is similar to the PPV attenuation law,and they have a high liner correlation.