径向不耦合装药孔壁冲击压力特性

Impact Pressure Characteristics of Radial Uncoupled Charge on Hole Wall

径向不耦合装药结构广泛应用于实际爆破工程中,为探究径向不耦合装药孔壁冲击压力的变化规律,基于冲击波理论,利用激波管模型对径向不耦合装药条件下孔内波系作用过程进行简化分析。研究了孔内爆炸冲击波在各介质面的冲击压力,获得了径向不耦合装药条件下孔壁初始冲击压力的计算表达式,模拟了径向不耦合装药时冲击波的作用过程。研究结果表明:径向空气层的存在极大削减了爆炸冲击波压力,孔壁峰值压力在不耦合系数1~2时发生指数型衰减,在不耦合系数大于2时,其衰减速度较缓慢。冲击波作用在孔壁处时存在多个波峰,且初始峰值压力最大,后续峰值压力随时间的延长逐渐减小;随着不耦合系数的增大,初始峰值压力逐渐减小且到达峰值压力的出现时间也逐渐延后;不耦合系数越大,多波峰特性越明显,不耦合系数较小时峰值压力较大,会对围岩产生较大的破坏。为减小对围岩的破坏且满足相应的爆破要求,应充分利用不耦合系数较大时的多波峰特性,根据岩石性质选择合理的径向装药系数。

The radial uncoupled charge structure is widely used in practical blasting engineering.In order to explore the variation law of the impact pressure of the hole wall of the radial uncoupled charge,based on the shock wave theory,the shock tube model is used to simplify the action process of the wave system in the hole under the condition of the radial uncoupled charge.The impact pressure of the blast wave in the hole on each medium surface is studied.The calculation expression of the initial impact pressure of the hole wall under the condition of radial uncoupled charge is obtained,and the action process of the blast wave under the condition of radial uncoupled charge is simulated.The results show that the existence of the radial air layer greatly reduces the pressure of the explosion shock wave.The peak pressure of the hole wall decays exponentially when the uncoupling coefficient is 1~2,and the decay rate is slow when the uncoupling coefficient is greater than 2.There are multiple peaks when the shock wave acts on the hole wall,and the initial peak pressure is the largest,and the subsequent peak pressure gradually decreases with time.With the increase of the uncoupling coefficient,the initial peak pressure gradually decreases and the time to reach the peak pressure gradually delays.The larger the uncoupling coefficient is,the more obvious the multi-peak characteristics are.When the uncoupling coefficient is small,the peak pressure is larger,which will cause greater damage to the surrounding rock.In order to reduce the damage to the surrounding rock and meet the corresponding blasting requirements,the multi-peak characteristics when the decoupling coefficient is large should be fully utilized,and a reasonable radial charge coefficient should be selected according to the rock properties.