基于LCEM-GFEM方法爆炸载荷作用下含缺陷岩体损伤机理研究

Damage mechanism and fracture evolution of rock containing defects with LCEM-GFEM method under explosive load

在爆破作业过程中,岩体缺陷对裂纹扩展具有显著影响。本研究基于全局有限元方法的局部黏结单元(LCEM-GFEM)方法构建数值模拟模型,研究爆破作用下含缺陷岩体的损伤演化和裂纹扩展模式。通过引入能量传递系数,定量分析了缺陷形态对应力波传播和衰减的影响。结果表明,缺陷形态对岩体的损伤特性和裂纹扩展具有显著影响。随着平行缺陷夹角的增加,爆破诱发的裂缝与衍生裂缝的合并路径从缺陷末端转移到了缺陷中间,能量传递系数增加,分形维度减小。随着平行缺陷之间的水平距离增加,平行缺陷之间的裂缝数目和能量传递系数相应减少。随着垂直缺陷之间的垂直距离增加,穿过缺陷C的主水平裂缝长度增加,能量传递系数和分形维度也增加。研究结果可为受到爆破荷载作用下含缺陷岩体的损伤特征提供指导。

Defects in rock masses have significant influence on the fracture propagation during blasting.In this study,a numerical model is developed using the local cohesive element based on the global finite element method(LCEMGFEM)to simulate the damage evolution and fracturing pattern of rock mass with defects under blasting load.The influence of defect morphology on the stress wave transmission and attenuation is quantified by introducing the energy transfer coefficient.The numerical results show that the defect morphology has prominent influence on the damage characteristics and fracture propagation of rock masses.The merging path of the blast-induced fracture and the derivative fracture shifts from the end to the middle of the defect as the angle of parallel defects increases.The energy transfer coefficient increases with the angle of parallel defects,while the fractal dimension decreases in this case.The number of fractures between the parallel defects and the energy transfer coefficient reduces significantly with the horizontal distance between parallel defects.With the increase of perpendicular distance between the vertical defects,the length of the main horizontal fracture passing through the defect C increases,as well as the energy transfer coefficient and fractal dimension.The numerical results would be beneficial to the understanding of the damage characteristics of defective rock masses under blasting load.