摘要
爆破技术广泛应用在国民经济建设和资源的开采中,爆破参数的设计与爆破的效果密切相关。随着煤矿行业的快速发展,煤炭开采面临着严峻的挑战,科学解决生产中所遇到的问题是保证煤矿安全高效开采的前提。煤矿深孔爆破技术逐渐应用于解决深部复杂问题和深部灾害的治理,控制孔在深孔爆破中起着重要的作用,对改善爆破效果具有重要的意义。
本文通过模型实验分析了控制孔与装药孔间的距离对爆破效果的影响。实验采用的装药孔直径为4mm,控制孔的直径为6mm,装药质量为1.0g,装药高度约l00mm,控制孔与装药孔之间的距离为d。当d=30mm时,控制孔在爆炸作用区的裂隙区,爆炸产生的爆生气体使两孔间的介质产生裂隙,裂纹扩展迅速,爆生气体从控制孔溢出,减小了破岩的能量,岩石不断裂;当d=60mm时,控制孔在爆炸作用区的塑性破坏区,控制孔使周围的岩石应力集中,达到岩石的断裂极限,岩石沿控制孔与装药孔的连线方向断裂,控制孔起到定向致裂的作用。当d≥90mm时,控制孔处于弹性区,岩石不沿控制孔与装药孔的连线方向破裂,控制孔的应力集中达不到岩石的破裂极限,岩石根据自身的损伤裂隙分布情况随机断裂,基本不受控制孔的影响。通过实验现象分析,得出控制孔所在爆炸作用区的位置对岩石的破裂至关重要,通过对应力波的分析,控制孔改变了孔周围岩石的应力状态,对控制岩石的破裂起到了重要的作用。
本文结合某煤矿深孔爆破弱化坚硬煤层顶板的试验,阐述了控制孔在深孔爆破中的应用。由于深部岩石的破坏没有足够的空间来满足裂隙的扩展,在爆破设计时,采用控制孔来补偿爆炸荷载作用区域介质产生位移所需空间,同时也能起到定向致裂的作用。试验结果表明:控制孔对实际工程的效果明显,有效的降低了岩体的整体性,使难冒顶板变为可冒顶板,从而大大降低了工作面支架的承载压力,同时也降低了生产成本,提高了开采效率。
控制孔为特殊条件下的工程爆破提供了解决问题的途径,合理设计控制孔参数对改善爆破效果、提高经济效益具有显著的作用。
Blasting technology is widely used in national economic construction and resource exploitation, and the result of blasting is closely related to the design of blasting parameters.With the rapid development of coal industy,coal exploitation is facing serious challenges.Solving the problem encounted in production scientificaly is the foundation of safely and efficiency exploitation.The deephole blasting technology apply to solve the difficulty problem underground and control deep hazards. Control hole plays an important role in deephole blasting. It is extremely significant for improving the blasting effect.
The model experiment is used for analysis the relationship of the distance between control hole and blasting hole to the blasting effect in this paper.In the experiment, the diameter of blasting hole and control hole are4mm and6mm, respectively. The mass of charge is1.0g, and the height of charge is about100mm. The distance between control hole and blasting hole is d.When d=3mm, control hole is located at crush zone. Under the action of explosion gas,the rock medium between the two holes was destory. The crack grew quickly and the explosion gas released from the control hole. The rock can not split due to energy of rock breaking was reduced. When d=6mm, control hole is located at crack zone. The stress concentrated and the value reach the fracture limit. The rock split along the line that joins the two holes. The control hole plays an important role in diractional fracturing. When d≥9mm, control hole is located at elastic zone. The rock split but not along the line that joins the two holes. The stress concentrated but not achieve the fracture limit. The rock split at random according to the damage crack distribute. From the experimental phenomenon,we may drew the conclusion that where the control hole located in the blasting acted zone is important for the rock split In hard rock roof weaken,there is not enough space to meet the demand of crack growth in view of the destory character of deep rock. In blasting design,the control hole is used for compensation the space that the rock medium in the blasting acted zone needed for replace.
Take the deephole blasting in rock roof weaken for example,the paper state the application of deephole blasting in coalmine.There is no enough space for the crack growth underground. The control hole is used to provided enough space for the crack growth. It also plays an important role in directional splite. From the application of control hole in the hard roof weaken,the effect is apperantly. The load of workface support reduced greatly because the completeness of rock is decreased. The roof rock was altered from hard to weak.
Control hole provided a way to solve the problem of engineering blasting in special conditions. The parameters of control hole is important for improving blasting result and increase the economic evenue.
引文
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