深部岩体在掏槽爆破过程中的损伤演化机制

摘要

为研究深部岩体掏槽爆破过程中岩体的损伤演化机制,将Cowper-Symonds硬化模型与拉压损伤模型耦合以后的模型嵌入到LS-DYNA软件中对其进行数值模拟研究.数值模拟结果表明:地应力及临空面的存在对岩体的损伤演化机制有影响,地应力存在对应力波所诱发的压力载荷产生抵制作用,使得岩体受压力荷载作用产生的损伤范围受到影响,随着地应力增大,掏槽爆破岩体的损伤范围变小;掏槽爆破中的中心孔有充当临空面的作用,使得应力波在遇到临空面时形成拉伸波,并造成中心孔附近岩体的拉损伤往岩体内部扩展,最终有加大掏槽孔周围岩体的损伤范围作用.%For the purpose of research on the damage evolution mechanism of deep rock mass in the process of cut blasting, a coupled model between the Cowper-Symonds hardening model and tension-compression damage model was implemented into commercial software LS-DYNA to simulate the damage evolution mechanism of deep rock mass in the process of cut blasting. The numerical results show that the in-situ stress and existence of free surface have an influence on the damage evolution mechanism of deep rock mass in the process of cut blasting. Since the in-situ stress exerts the resistance on the pressure load induced by blasting load in the rock mass, the damage scope of the rock mass surrounding the cut holes is influenced accordingly, and the damage scope decreases with the increase of the in-situ stress. However, in the process of cut blasting, the center hole as a free surface can enlarge the damage scope surrounding the cut holes. That is because the stress waves change into tensile stress waves upon the reflection at the free surface, here, and the tensile damage caused by tensile stress waves at the free surface propagates toward the inner rock mass, and eventually the damage scope of the rock mass surrounding the cut holes is enlarged.