地应力条件下爆破载荷破岩的DDA模拟研究

为探究地应力条件下的岩石爆破破岩特征与机理,基于非连续变形分析(DDA)方法建立岩石爆破力学模拟模型,分别考虑爆生气体压力和爆炸应力波的爆破载荷作用形式,对双向等值和不等值地应力条件下均质岩石的单孔爆破进行数值模拟,研究地应力对爆生气体压力和爆炸应力波破岩效果的影响。结果表明:对于均质岩石,在双向等值初始地应力条件下,爆破裂纹区近似为圆形,其面积随初始地应力的增大而减小,且双向等值初始地应力大小的变化对爆炸应力波的破岩作用影响更大;在双向不等值初始地应力条件下,爆破裂纹区呈扁平形,裂纹主要朝较大压应力方向扩展,且侧压系数的变化对爆生气体的破岩作用影响更大。研究结果对爆破工程实践具有一定的理论参考意义。

DDA simulations of rock fracture by blasting loads under geostress conditions

To explore the mechanism and characteristics of rock fracture in rock blasting under geostress conditions,mechanical simulation models of rock blasting under geostress are constructed with the discontinuous deformation analysis(DDA)method,and the two types of blasting loads of explosion-induced stress wave and explosion gas pressure are considered.The influence of the geostress with different side pressure coefficient on the fracture of homogeneous rock by the two types of blasting loads is numerically investigated through the simulations of single borehole rock blasting examples.Results indicate that,for homogeneous rock,under bi-directional equivalence initial geostress,an approximately circular rock fracturing zone is always produced and its area decreases with the increase of the geostress magnitude,and the fracture of rock under explosion-induced stress wave is more likely to be influenced as compared with that under explosion gas pressure.Under bi-directional unequal initial geostress,a flat zone of rock fracturing towards the maximum direction of the geostress is preferred to be generated,and the fracture of rock under explosion gas pressure is more likely to be influenced by the change of the side pressure coefficient.The research has certain theoretical reference significance in blasting engineering practice.