高地应力下岩体的爆破损伤及能量特性

Blasting Damage and Energy Characteristics of Rock Mass under High in-Situ Stress

在深层岩体地下工程中,岩体的爆破效果与地应力密切相关。基于岩体-空气流固耦合模型,采用理论分析与LS-DYNA有限元数值模拟相结合的方式,研究了不同地应力和侧压系数条件下岩体爆破损伤效果以及岩体非弹性边界处能量及质点峰值振动速度阈值的变化规律。结果表明:岩体的损伤范围和裂纹扩展在一定程度上受到地应力的抑制作用,地应力越大,损伤范围和裂纹长度越小;不同地应力下,非弹性区与弹性区边界处的能量差随侧压系数的增大而减小,当侧压系数一定时,能量随地应力的增大而增大;高地应力状态下,利用质点峰值振动速度阈值判据进行岩体爆破安全控制是不可靠的。

In blasting excavation of deep rock mass engineering,the blasting effect is closely related to ground stress.Based on the rock mass-air fluid-solid coupling model,the blasting damage effect of rock mass under different in-situ stress and lateral pressure coefficient,and the variation rule of energy and peak particle velocity(PPV)threshold at inelastic boundary of rock mass were studied by combining theoretical analysis and LS-DYNA finite element numerical simulation.The results show that the damage range and crack propagation of rock mass are restrained by in-situ stress to a certain extent.The larger the in-situ stress is,the smaller the damage range and crack length will be.Under different ground stresses,the energy difference between the inelastic zone and the elastic zone decreases with the increase of the lateral pressure coefficient.When the lateral pressure coefficient is constant,the energy increases with the increase of ground stress.Under the condition of high in-situ stress,it is inaccurate to use the PPV threshold to determine the safety control of rock blasting.