【摘要】 应用动态焦散线测试系统,模拟断续节理岩体断裂爆破过程,进行了有机玻璃(PMMA)模型透射式动态焦散线实验,研究了无充填和充填断续节理对切缝药包断裂控制爆破裂纹扩展规律的影响和裂纹扩展的机理.结果表明:切缝药包爆炸应力波到达无充填断续节理面后,在节理的两端产生了两条翼裂纹,翼裂纹基本沿原爆生裂纹方向继续扩展,最长达2.5 cm,翼裂纹尖端复合应力强度因子呈由小变大再变小连续波动变化的趋势,裂纹扩展速度和加速度变化趋势与应力强度因子变化类似;爆炸应力波到达充填断续节理面后,同样在节理两端产生了两条翼裂纹,翼裂纹向两侧偏移很大,翼裂纹最长达4 cm,翼裂纹尖端应力强度因子KdⅠ呈由小变大再变小连续波动变化的趋势,动态应力强度因子KdⅡ则呈由大变小连续振荡变化的趋势,而且翼裂纹扩展过程中具有起裂时间早、裂纹扩展速度和加速度峰值大的特征.更多还原

【Abstract】 A PMMA(polymethyl methacrylate) model of a transmission-type experiment with dynamic caustic was carried out with a dynamic caustic-test system to simulate the blasting process of rock with discontinuous joints.The crack propagation mechanism and effect of filled and unfilled discontinuous joints,given the rules of crack propagation of cutting seam cartridge fractures,were studied under controlled blasting.Our experimental results show that two wing cracks appeared at both ends of the joints after the explosive stress wave reached the unfilled discontinuous joint plane.Wing cracks generally expand along the initial detonation crack.The longest wing crack was 2.5 cm.The mixed-mode stress intensity factor at the tips of the wing cracks changed from small to large.The change in crack speed and acceleration is similar to that of the stress intensity factor.Two wing cracks appeared at both ends of the joint after the explosive stress wave reached the filled discontinuous joint plane.Wing cracks are offset much to both sides.The longest wing crack is 4 cm.The stress intensity factor,at the tips of the wing cracks continuously fluctuates from small to large while the dynamic stress intensity factor continuously fluctuates from large to small.Wing cracks appeared at an early stage,with a large propagation speed and acceleration.更多还原