布孔方式对支撑梁爆破拆除的影响机制

Influence Mechanism of Blasthole Arrangement on Explosive Demolition of Support Beam

支撑梁爆炸毁伤破坏效应的数值模拟及理论研究是创新改进爆破拆除方法的前提。结合钢筋混凝土支撑梁爆破拆除工程实际,针对垂直布孔与多向协同布孔分别建立其共节点分离式模型,比较分析梁内Von Mises等效应力分布规律、爆炸荷载空间分布特点及其破碎形态。结果表明:相邻炮孔炸药能量分别在50μs、60μs开始耦合叠加,叠加区应力水平显著增高;在混凝土碎胀效应及反射拉伸波共同作用下,支撑梁表面材料单元以拉伸破坏为主;相同炸药单耗时,多向协同布孔法可促进梁内爆炸荷载的均匀分布,有效改善拆除效果;材料失效演变过程表明,支撑梁破碎形态分别在255μs、265μs时刻稳定下来,采取先下后上的起爆顺序,能有效防治爆破飞石危害。

Numerical simulation and theoretical study of explosion damage effect of support beam are the prerequisite for innovation and improvement of demolition blasting method. Combined with engineering practice,the separated common-node blasting model of reinforced concrete support beam is established with vertical and multi-directional synergy arrangement of blasthole. Under which,the distribution law of Von Mises equivalent stress,the spatial distribution characteristics of explosive load and the shape of fracture zone are analyzed and compared. The result shows that the explosive energy of the adjacent holes is coupled and superposed at 50 μs and 60 μs respectively,and the stress level of the superposition region is obviously higher than that of other regions. Under the combined action of the concrete dilatancy effect and the reflected tensile wave,tensile failure is dominated on the supporting beam surface.With the same unit explosive consumption,the multi-directional synergy arrangement of blasthole can promote the uniform distribution of explosive load in the beam,effectively improve the demolition effect. Furthermore,material failure evolution process shows that,the fracture shape of the support beam is stabilized at 255 μs and 265 μs respectively. Priming sequence from bottom to top. Can prevent the hazard of blasting slungshot significantly.