Nine blasts with cylindrical granite specimens were carried out under different stemming conditions. All rock specimens had a diameter of 240 mm and a length of 300 mm. Explosive Pentaerythritol tetranitrate (PETN) with specific charges 0.2 and 0.3 kg/m³ were used, and the blasts were carried out in a large explosion chamber. Each rock specimen was enclosed by a steel box in the chamber during blasting, without constraint or confinement to the specimen from lateral and top sides. During blasting a high-speed camera was used to film the blasting process and monitor the gas ejection. After each blast all fragments were collected, sieved and analyzed. The experimental results showed that: (1) the blasts with full sand stemming yielded better (finer) fragmentation than the blasts with partial steel stemming at a constant specific charge, and (2) gas ejection from the collars of blastholes occurred much earlier in the blasts with partial steel stemming than in the blasts with full sand stemming. Based on the experimental results, it can be concluded that it is extremely important to prevent gas ejection from the collars in order to achieve desirable rock fragmentation.

在不同的填塞条件下对圆柱形花岗岩标本进行了9次爆炸。所有岩石样本的直径为240毫米，长度为300毫米。爆炸性季戊四醇四硝酸盐（PETN），比电荷为0.2和0.3 kg / m ³使用，爆炸是在一个大爆炸室内进行的。在爆破过程中，每个岩石标本都由室内的一个钢箱封闭，而不受侧面或顶面的约束或限制。喷砂过程中，使用高速相机拍摄喷砂过程并监视气体喷射。每次爆炸后，收集所有碎片，筛分并分析。实验结果表明：（1）充满全沙的爆炸比细钢以恒定的装料电荷产生的爆破（更细）碎裂；（2）爆破孔环中的瓦斯喷射发生得较早。带有部分钢渣的爆破比具有完全砂渣的爆破。根据实验结果，