钻孔爆破孔间最佳延时时间模型试验研究

摘要

To explore the optimal delay time between the blast holes,high precision experiment device and technology are adopted,including high speed photography,dynamic strain test method,digital electronic ignition system and others. Consider-ing the factors from new free surface forming time and the residual mount of stress wave,investigation is made through concrete slope model of single hole blasting of high speed photography and hole by hole blasting dynamical strain test. The results show that:when the delay time between holes is 5 ms,the stress wave superposition between two holes is good,but the good free sur-face is not formed at the later hole;When the delay time between holes is 10 ms,the formation of cracks in 10 mm above is en-sured,and also the subsequent hole still have a larger residual stress existing in the medium. It is conducive to the formation of good crushing effect;When the delay time between hole is 15ms,the residual stress generated by the front hole almost disap-peared;When the delay time between holes is above 20 ms,blasting of the latter hole is not affected by the front hole. After comprehensive consideration,it is suggested that the optimal delay time between holes ranges from 10 to 15 ms in hole-by-hole millisecond blasting.%为探寻钻孔爆破孔间最佳延期时间，采用高速摄影技术、动态应变测试方法以及数码电子起爆系统等高精度试验设备，从新自由面形成时间和应力波残余量两方面因素考虑，通过混凝土边坡模型单孔爆破高速摄影拍摄和逐孔爆破动态应变测试试验进行分析研究。孔间延时时间为5 ms时，前后炮孔间应力波叠加情况很好，但是后孔起爆时未能形成良好的自由面；当孔间延时时间为10 ms时，既能保证有10 mm以上的裂缝形成，后孔起爆时又仍有较大残余应力存在于介质中，有利于形成良好的破碎效果；当孔间延时时间为15 ms时，介质中由前孔爆破产生的残余应力几乎消失；当孔间岩石在20 ms以上时，后孔起爆不受前孔爆破应力波影响。综合考虑，建议逐孔微差爆破中孔间最佳延时时间控制在10~15 ms。