摘要
本文将聚能装药结构的爆炸聚能原理应用于石材矿山的切割开采之中,首先分析了聚能药包爆炸作用对石材的切割原理,其中,着重研究了炮孔壁上的聚能开裂和裂缝扩展以及贯通的物理过程,推导了裂缝形成过程中各个阶段的力学条件;然后,将聚能切割原理应用于大理石的切割爆破之中,并对现场切割爆破效果和影响聚能效应的因素进行了分析讨论,试验研究表明,文中所得的结论与现场试验的结果相吻合。
The theory of cumulative charge explosion is applied to cut rock materials in this paper. The author analyses the cumulative effects in cutting rock fundamentals first. In this part the rock cracking process is emphatically studied and divided into three periods which are cumulative crack initiation, initial crack extension and crack formation. The crack initiation on the wall of the explosion hole is because of the action of the cumulative metal flow. The criterion of crack initiation is given bywhere u-rock poisson' s ratio, p= material density of cumulative hood, v= velocity of cumulative flow, s= dynamic tensile strength of the rock.The cumulative flow and the quasistatic pressure of explosion gases provide with the power of crack extension in its initial extension period. Thus we can obtain the criterion of initial crack extensionwhere R= radius of the explosion hole, a1= length of crack initiation, r= distance between a certain point and the crack tip, p1 quasistatic pressure of explosion gases in explosion hole, F1= a coefficient concerned with the radius of the explosion hole and the length of crack extension.After the cumulative flow disappears , only the pressure of explosion gases causes crack continuously extending till the crack arrests. In this process the rock occurs fracture failure and its failure criterion is given belowwhere p2= explosion gases pressure through its attenuation, a2 crack length when cumulative flow disappears, K = rock dynamic plane strain fracture tenacity.Then the author explains the conditions and the results of field tests and analyses the factors which affect the effect of cumulative cutting rock. These factors are the charge quantity, charge structure, the material quality and shape and size of the cumulative hood respectively. Clearly the formation of the cumulative flow depends upon the detonation pressure, velocity, the charge diameter and the material of the cumulative hood. Especially the later has a great influence on the effects of cumulative cutting rock.
出处
《爆炸与冲击》
EI
CAS
CSCD
北大核心
1991年第3期265-272,共8页
Explosion and Shock Waves
关键词
聚能药包
切割爆破
力学条件
cumulative charge, cutting blasting, mechanical criterion, rock meterial mining
