轴向不耦合装药结构水介质不耦合系数及位置效应分析

Analysis of water medium decoupling ratio and position effect of axial decoupling charge structure

为了改善爆破破岩效果,减少爆破的有害效应,并减少岩石大块率的产生,采用ANSYS/LS-DYNA模拟水介质所处的不同位置以及不同不耦合系数对爆破效果的影响,通过优化装药结构以期找到合理的装药结构和较优的不耦合系数。基于显式动力学有限元软件ANSYS/LS-DYNA建立三维数值计算模型,以爆炸应力云图、峰值拉应力分布为评判依据,对轴向不耦合装药位置、轴向不耦合系数等因素进行了对比分析。研究表明:轴向不耦合装药位置的不同,对最大拉应力值的影响不同,虽然水介质在中部和在顶部的装药结构在孔口段处的最大拉应力值远大于岩石的抗拉强度,但综合考虑孔底岩石所受的损伤效应,得出水介质在两端的装药结构能量分布较为均匀,孔底岩石受的损伤大大减少,减少对未爆岩体的损伤和扰动;以最大拉应力值作为爆破效果的评判标准,在不耦合系数1.3~1.8之间,峰值拉应力存在极大值,即对应一个最优的不耦合系数,同时较耦合装药结构相比,减少了粉层和有毒有害气体的生成。

In order to improve the effect of blasting rock,reduce the harmful effects of blasting,and reduce the generation of rock mass rate,ANSYS/LS-DYNA is used to simulate the influence of different positions of the water medium and different decoupling ratio on the blasting effect,and by optimizing the charge structure to find a reasonable charge structure and a better decoupling ratio.Based on the explicit dynamics finite element software ANSYS/LS-DYNA,a three-dimensional numerical calculation model was established.Based on the explosion stress nephogram and the peak distribution of tensile stress,the axial decoupling charge position and the axial decoupling ratio were compared and analyzed.Studies have shown that the difference in the position of the axially decoupled charge has different effects on the maximum tensile stress value,although the maximum tensile stress value at the orifice section of the charge structure with the water medium at the middle and the water medium at the top is much greater than the tensile strength of the rock.But comprehensively considering the damage effect of the rock at the bottom of the bore,it is concluded that the energy distribution of the charge structure of the water medium at both ends is relatively uniform.The damage to the rock at the bottom of the hole is greatly reduced,the damage and disturbance to the unexploded rock mass are reduced.Taking the maximum tensile stress value as the evaluation standard of blasting effect,the maximum value of tensile stress peak value exists between the decoupling ratio 1.3~1.8,which corresponds to an optimal decoupling ratio.At the same time,compared with the coupled charge structure,it is reduced to powder layer and the generation of toxic and harmful gases.