孔排距对高台阶抛掷爆破效果影响的模型试验

为研究高台阶抛掷爆破中孔距、排距对抛掷爆破效果的影响规律,以黑岱沟露天煤矿抛掷爆破为原型,基于相似理论,展开高台阶抛掷爆破模型试验,并进行了超动态应力应变的测试与分析,得出:有效抛掷率E_p和最远抛距L_m随孔距的增加或排距的减小而增大,但当孔距增加到排距的1.45倍时E_p开始下降;排距减小到孔距的0.66倍时L_m开始减小;即当炮孔密集系数m满足1.4-1,卸载率为51 s^-1;拉应变的加载率为11 s^-1,卸载率为3.6 s^-1;结合现场爆破情况分析,砂浆材料拉伸破坏时,其拉应变峰值在160 με以上。

Model Experiment Study on the Effect of Casting Parameters on the Cast Percentage of High Bench Cast Blasting

To search the effect of hole and row spacing on blasting effect in high bench cast blasting, taking the throwing blasting of Heidaigou open pit coal mine as the prototype, model test of high order throwing blasting was carried out based on similarity theory, and the test and analysis of super dynamic compression were also carried out. The results show that the effective cast percentage E_p and the farthest throw distance L_m increase with the increase of the hole spacing or the decrease of the row spacing, but when the hole spacing increases to 1.45 times of the row spacing, E_p begins to decline; When the row spacing is reduced to 0.66 times of the hole distance, the L_m begins to decrease; The value of optimal m could be the one between 1.4 and 1.6, depending on the particular experimental conditions. When explosive stress wave propagates in mortar, the wave loading rate of compressive strain is about 200 s^-1, the unloading ratio is about 51 s^-1. And the wave loading rate of tensile strain is about 11 s^-1, the unloading ratio is about 3.6 s^-1; According to the analysis of field blasting, the peak tensile strain value of mortar material is above 160 με when tensile failure occurs.