摘要
预裂爆破的现场实践表明,诸如节理、软弱夹层和断层等地质不连续面是影响预裂爆破效果的一个重要因素。运用LS-DYNA 3D程序研究了不同角度的节理对预裂爆破效果的影响。通过数值模拟发现,岩体中节理的存在对预裂爆破效果影响显著,其吸收应力波能量并阻碍应力波的传播,且影响预裂缝产状。研究结果表明,节理附近的预裂缝大多沿节理垂直方向开裂,逐渐与被破坏节理连接,节理夹角较小时,易形成锯齿状裂缝,且较难贯通。随着节理与炮孔连线夹角的增大,应力波在节理处的透射率越大,节理附近位置上的质点振速也越大,预裂缝更趋于平直且更易贯通。当节理垂直炮孔连线时透射率最大,所形成的预裂缝与炮孔连线基本重合,不会出现锯齿形裂缝,相对成缝效果最佳。
Field practice demonstrates that geological discontinuities such as joints, weak intercalations, as well as faults, are a key factor controlling result of presplit blasting operations. The influence of angle of geological joints is investigated using the software LS-DYNA 3D. The numerical simulation of the process of presplit blasting in jointed models shows that the existence of the joint in rock mass can affect presplitting blasting significantly. The joint absorbs stress wave energy and prevents the transmission of stress wave, also impacts presplitting fissure occurrence. The cracks near joints mostly run along the direction vertical to the joints and gradually connect with the joints. When the angle between joint and the direction of designed presplit is small, the zigzag-shaped cracks are likely to rise, but hardly to penetrate. With increase of the angle, the effect of the stress wave transmission over the joints, as well as the particle vibration velocity near the joints can increase, and the produced presplitting cracks are more likely to straightly penetrate from one to another along the designed presplit line. When the joints and the designed presplit line are perpendicular to each other, the stress wave transmission over the joints reaches maximum and the cracks are likely to be in the same line connecting the presplit holes. Thus it becomes less possible for the zigzag-shaped crack to occur. The effect of presplitting to crack occurrence is best.
出处
《岩土力学》
EI
CAS
CSCD
北大核心
2015年第1期189-194,204,共7页
Rock and Soil Mechanics
关键词
预裂爆破
节理岩体
数值模拟
预裂缝
应力波
presplitting blasting
jointed rock
numerical simulation
cracking from presplit blasting
stress wave
