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本文用动光弹方法研究了炸药爆炸产生的气体压力对炮孔周围应力场的影响。炸药分别装在两个模型的中心炮孔中。一个模型中为敞露装药,另一个模型将装药容纳在一个特殊的密封装置中。多火花式动态光弹性仪被用来记录膨胀波和剪切波的传播以及裂纹的扩展。文章给出了爆生气体增压作用的一些重要结论:1.密封装药时膨胀波脉冲幅度比敞露装药时的幅度高一倍左右,脉冲宽度也有所增大。2.密封装药时最大径向位移是敞露装药时的2—3.5倍,最大径向和切向应变的绝对值是敞露装药时的2.5倍左右,最大径向和切向应力的绝对值是敞露装药时的2倍左右。3.无论是密封装药或是敞露装药,在入射 P 波的压缩相中,|σ_r|_(max)对|σ_θ|_(max)的比值约为3。4.密封装药时炮孔周围的径向裂纹的平均长度为敞露装药时的8/3倍。
In this paper, the effect of gas pressure generated by the explosive detonation on the stress field around the borehole was studied by using the dynamic photoelastic method. Explosives were installed in the central hole in the two models. One model is unpacked and the other model holds the charge in a special seal. Multi-spark dynamic photoelasticity was used to record the propagation of the expansion and shear waves and the propagation of cracks. The article gives some important conclusions about the supercharging effect of gas explosion: 1. The pulse amplitude of expansion wave is about one time higher than that of open charge, and the pulse width also increases. 2. The maximum radial displacement of the seal charge is 2-3.5 times of the open charge, and the absolute value of the maximum radial and tangential strain is about 2.5 times when the open charge is applied. The maximum radial and tangential stress The absolute value is about 2 times the open charge. 3. The ratio of | σ_r | _ (max) to | σ_θ | _ (max) is about 3.4 in the compressed phase of the incident P-wave, both for hermetic charge and open charge. The average length of radial cracks around the blast hole is 8/3 times longer than the open charge.