层理面对水压爆破应力波传播规律的影响

Infulence of bedding planes on stress wave propagation in hydraulic blasting

水压爆破应力波的传播过程决定了爆破的作用效果及影响范围,层状岩体中的层理面特征对水压爆破应力波的传播路径及衰减具有直接影响。为明确水压爆破应力波在层状岩体内的传播规律及影响因素,采用理论分析和数值模拟相结合的方法,研究了层理面位置及其介质属性对水压爆破应力波传播的影响规律。结果表明:水压爆破相对于常规爆破产生的初始应力更大,破碎效果更明显;水压爆破应力波传播至层理面时会发生反射和透射,导致层理面区域的岩体应力状态发生改变,使得临近层理面的入射应力峰值明显降低;层理面与爆源的距离越小,层理面对应力波传播和裂纹扩展的抑制作用越明显,随着该距离的增大,反射应力波会促进层理面与爆源间的裂纹扩展并诱导初始裂纹继续延伸,同时改变横向裂纹的扩展方向;层理面介质对应力波的传播和裂纹的扩散影响显著,层理面介质与岩体的性能差异越大,应力波在层理面的衰减越严重,降低了应力波的有效作用范围。

The propagation process of hydraulic blasting stress waves determines the effect and scope of blasting,and bedding plane features of layered rock mass have a direct influence on the propagation path and attenuation of hydraulic blasting stress wave.In order to clarify the propagation law and influencing factors of hydraulic blasting stress wave in the layered rock mass,the theoretical analysis combined with numerical simulation was used to study the influence law of the position and the medium of bedding on the propagation of hydraulic blasting stress wave.The results show that the initial pressure produced by hydraulic blasting is larger and the crushing effect is more obvious than those produced by conventional blasting.The stress wave of hydraulic blasting will reflect and transmit when it propagates to the bedding plane,which leads to the change of stress state of the rock in the area,and significant reduce of the peak value of incident stress near the area.The smaller the distance between the bedding plane and the explosion source,the more obvious the suppression effect on stress wave propagation and crack propagation.As the distance increases,the reflected stress waves promote the crack propagation between the bedding plane and the explosion source and induce the initial crack to continuously spread,and at the same time,the propagation direction of transverse crack is changed.The layered medium has a significant influence on the propagation of stress waves and the spread of cracks.The greater the performance difference between the bedding plane medium and the rock mass,the more serious the attenuation of the stress wave on the bedding plane,which reduces the effective action range of the stress wave.