不耦合装药系数对岩体爆破损伤的影响

Effect of Uncoupled Charge Coefficients on Rock Blast Damage

在爆破工程中,选择合适的装药结构能够有效提高炸药利用率,从而改善爆破效果。基于RHT(Riedel-Hiermaier-Thomamodel)动态响应力学关系,采用ANSYS/LS-DYNA软件研究了偏心不耦合装药条件下不耦合系数K对岩体爆破荷载的影响,以及爆破过程中岩体的损伤情况。通过建立单孔偏心不耦合爆破模型,分析了不耦合系数K为1.0、1.5、2.0、2.5、3.0和3.5条件下的有效应力、振动速度、爆破地震波能量和损伤状况。同时,研究了不同不耦合系数K条件下爆心距(l)与损伤度(D)、质点振动速度(PPV)与爆心距(l),以及振动速度(vpp)与损伤度(D)之间的关系。结果表明:随着不耦合系数K的增大,耦合侧与不耦合侧有效应力和峰值振动速度、地震波峰值能量略微减小;粉碎区和裂隙区范围逐渐减小,且粉碎区损伤半径较裂隙区减小速率更大。岩体损伤程度和质点振动速度(vpp)均随着爆心距的增大而逐渐减小。质点振动速度越大损伤程度也越大,当vpp=50.4 cm/s时,岩体中的损伤变量达到损伤破坏阈值(D=0.19);当vpp>140.6 cm/s时,损伤度D>0.80。

A suitable charging structure in blasting engineering can effectively improve the utilization rate of explosives and thus improve the blasting effect.Based on the RHT(Riedel-Hiermaier-Thomamodel)dynamic response mechanics relationship,ANSYS/LS-DYNA software was used to study the effect of the uncoupling coefficient K on the blasting load of rock body under the condition of eccentric uncoupled charge and the damage of rock body during blasting.The effective stress,vibration velocity,seismic wave energy and damage conditions under uncoupling coefficients K=1.0,1.5,2.0,2.5,3.0 and 3.5 were analyzed by establishing a singlehole eccentric uncoupled blasting model.In addition,the relationship between burst center distance l and damage degree D,mass vibration velocity PPV and burst center distance l,and vibration velocity vpp and damage degree D under different conditions of uncoupling coefficients K were investigated.The results show that with the increase of the uncoupling coefficient K,the effective stress and peak vibration velocity of the coupled and uncoupled sides and the peak energy of the seismic wave decreases slightly.The range of the crushed zone and the fracture zone decreases gradually,and the radius of the damage in the crushed zone is larger than the rate of decrease in the fracture zone.The damage degree of rock body and the mass vibration velocity vpp are gradually reduced with the increase in the burst center distance.The greater the particle vibration velocity vpp is,the larger the damage degree is.When vpp reached 50.4 cm/s,the damage variable D in the rock body reached the damage failure threshold of 0.19.When vpp>140.6 cm/s,the damage degree D>0.80.