爆炸荷载作用下缺陷岩体破坏特征的数值模拟研究

为了研究爆炸荷载下含缺陷岩体的破坏规律,根据已有的实验结果建立了在爆炸荷载下含缺陷岩体的漏斗爆破模型,所考虑的缺陷包括孔洞、孔隙和微小的张开型节理.缺陷是随机分布的,且对于缺陷内部考虑了两种情况,一种是含水的,另一种是空的.依据已有花岗岩的实验结果,通过拟合得到了其冲击状态方程,并将其应用于炸药附近的花岗岩,而对于远离炸药的花岗岩,采用了线性状态方程.根据实验结果,将花岗岩的动态强度设计成随应变率变化的变量.模拟结果表明,在爆破荷载下,湿润的岩体比其相应干燥岩体的动态强度低;在应力波作用下缺陷密度越大,其岩体的破坏范围越小;最后,讨论了巷道附近的爆破过程对巷道稳定性的影响.

Numerical Predication on the Fracture Characteristics of Rocks with Defects Under Blasting Loads

A crater blasting model of rock with pre-existing defects, including voids, pores and small open joints, under blasting loads are established, based on experiment results. The defects are randomly distributed, and are empty or saturated with water. A shock equation of state (EOS), obtained from the existing test results, is employed for the granite near the explosive charge, and for the granite far from the charge, a linear EOS is applied. A modified principal stress failure criterion is applied to determining the granite statuses. The granite dynamic strengths, which increase with strain rate, are calculated from the existing test results. The simulation results show that under blasting, as rock contains water, its strength will decrease; the larger the defect density is, the smaller the damage range is; and finally, the effect of blasting on tunnel stability is discussed.