【摘要】 应用动态焦散线测试系统,模拟含缺陷岩体爆破过程,进行了PMMA(有机玻璃)模型透射式动态焦散线试验,着重研究了与预制裂隙共线的炮孔爆炸作用下裂纹扩展的规律.试验结果表明,爆炸载荷下裂隙两端分别产生了1条翼裂纹A和B,翼裂纹A的长度大于翼裂纹B的长度,2条翼裂纹向相反的方向扩展;随着翼裂纹长度的增加,裂纹扩展速度出现快速增加,减少,再增加,再减少的振荡过程;翼裂纹扩展加速度也始终存在着加速与减速不断交替变化的现象;翼裂纹尖端动态应力强度因子呈快速增大到逐渐减小连续振荡变化的趋势,动态应力强度因子KdⅠ最大值为1.3 MN/m3/2,KdⅠ一直大于KdⅡ.更多还原

【Abstract】 Using the dynamic caustics-test system,the PMMA(Polymethyl Methacrylate) model transmission-type experiment of dynamic caustics was carried out to simulate blasting process of rock containing flaws.The crack propagation law under blasting load of the borehole in the same line of the prefabricated flaw was studied.The experimental results show that two wing cracks appear at both ends of the flaw in material subjected to blasting load.The wing crack A length is longer than wing crack B length.Two wing cracks expand along reverse direction.The crack velocity oscillates with the increase of crack length,and there are several stages of recognized increasing,decreasing,reincreasing and redecreasing regions during the whole fracture process.The wing crack acceleration presents the alternation with increasing and decreasing.Dynamic stress intensity factors also present the wavy variation of quick increasing and gradual decreasing.The maximum value of dynamic stress intensity factor KdⅠ=1.3 MN/ m3/2,and the value of KdⅠ is larger than KdⅡ at all times.更多还原