基于ANSYS/LS-DYNA的液态CO_(2)相变破岩裂纹扩展特征研究

Study on crack propagation characteristics of liquid CO_(2)phase transition rock breaking based on ANSYS/LS-DYNA

为研究液态CO_(2)相变爆破技术破岩机理,更好地推广这种安全爆破技术,采用ANSYS/LS-DYNA仿真软件对液态CO_(2)相变爆破岩石的裂纹扩展特征及影响致裂结果的关键因素进行研究。基于仿真结果对比CO_(2)爆破和炸药爆破岩石损伤裂纹的区别,并研究岩石爆破裂纹的扩展形式与应力波加载速率和岩石强度的关系,以及地应力对爆破裂纹扩展的影响。研究结果表明:CO_(2)爆破岩石产生裂纹条数较少的原因是其爆炸应力波的加载速率较低,且只有爆炸应力波强度高于岩石动态抗压强度时才会产生粉碎区。初始地应力会抑制爆破裂纹的扩展,在各向异性的地应力作用下,裂纹会朝着最大地应力的方向扩展。研究结果可为实际工程中的爆破参数选取提供参考。

In order to study the rock breaking mechanism of liquid CO_(2)phase transition blasting technology and better promote this safe blasting technology,the finite element simulation software ANSYS/LS-DYNA was used to study the crack propagation characteristics of rock by liquid CO_(2)phase transition blasting and the key factors affecting the cracking results.Based on the numerical simulation results,the difference of rock damage cracks between CO_(2)blasting and explosive blasting was compared.The relationship between the propagation form of rock blasting crack and the loading rate of stress wave and the strength of rock,as well as the influence of in-situ stress on the growth of blasting crack were studied.The results showed that the reason why there are fewer cracks in CO_(2)blasting rock is that the loading rate of the blast stress wave is low,and only when the strength of blasting stress wave is higher than the dynamic compressive strength of rock,the crushing zone will be generated.The initial in-situ stress will inhibit the propagation of blasting crack,and under the anisotropic in-situ stress,the crack will expand towards the direction of the maximum in-situ stress.The research results can provide reference for the selection of blasting parameters in practical engineering.