坑道口部爆炸冲击波压力传播规律

坑道口部是防护的重点和难点.利用显式动力学有限元软件,通过合理简化假设,对典型的等截面直墙圆拱坑道口部爆炸的冲击波波动过程进行了数值模拟,形象揭示出坑道中冲击波压力传播规律,即坑道中冲击波压力首先直线上升至最大值,随后由于坑道壁来回反射,出现了与自由大气中理想冲击波指数衰减不同的多个波峰震荡,并得到了峰值压力随距离衰减的模拟结果.再采用相似比为1/5的室外大比例模型,对0.8 kg,0.6 kg和0.4 kg 3种集团装药在坑道口部爆炸的冲击波压力传播规律进行了试验研究,由实测数据拟合出了冲击波峰值压力计算经验公式.结果表明,试验拟合公式与数值模拟及其他经验公式一致性较好,具有一定的工程使用价值.

Study of Shock Wave Pressure Propagation Laws of the Explosion at the Tunnel Entrance

Entrance is the keystone part of a tunnel and is very difficult to be protected. The dynamic finite element program is employed to simulate the explosion shock wave propagation in typical wall-arch tunnel with uniform section. Some parameters are simplified via assumptions. In course of a numerical simulation, the shock wave pressure value in the tunnel rises to the maximum straight in a moment. Then, due to the reflection back and forth along the inner surface, multi-peak appears, which is different from the ideal shock wave by exponential decay in the free atmosphere. More, the outdoor large-scale model test is tried on with the similar ratio as 1/5, including three-level quantities 0.8kg, 0.6kg and 0.4kg TNT. It further reveals the pressure propagation laws in the tunnel. And at the same time this article gives the fitting empirical formula of the peak pressure by dimensional theory according to the measured test data. The result shows that the fitting test is consistence with the numerical simulation and other empirical formulas.