Study On The Aettenuation Law And Safe Distance Of Gas Explosion Shock Wave

Gas explosion is one of the serious disasters,in case of which will cause heavy casualties in coal mines. Explosion shock wave first destroy the underground ventilation system, and then the poison gas spread in the out-of-control ventilation system, resulting in disaster area enlargement. Lacking of research on the laws of the explosion shock wave attenuation in complicated ventilation network, makes no rules to follow at the scene of gas explosion rescue, especially the determination of the safe rescue distance. On account of this, the paper mainly studies the attenuation laws and the safe distance on the explosion shock wave in underground roadways. The results are beneficial to the prevention and rescue of gas explosion in coal mines.Gas explosion shock wave, consisting of overpressure and dynamic pressure(impact aie-flow), will change regularly with the spread of explosion in roadway. Based on the dimensional method and explosive similar law, comprehensive considering the gas accumulation, the sectional area, the roughness coefficient and the distance, the attenuation similarity model of shock wave overpressure and impact aie-flow velocity in excavation roadway are constructed; Based on the gas explosion experimental data in the test roadway, adopting the regression analysis and data fitting function of the MATLAB software, the attenuation mathematics model of shock wave overpressure and impact air-flow velocity with distance in straight excavation roadway are obtained. Furthermore, according to the energy law of similitude, the attenuation relation extends to general roadway.The extrusion of overpressure and the collsion of dynamic pressure will cause harm to human body. After having studied the attenuation law of the gas explosion shock wave, to get the safe distance on the rescue scene, fistly, 19.6k Pa and 17.1m/s are determined as the critical shock wave parameters; Secondly,it is assumed that human body will be in a safety state when they suffer a overpressure and airflow velocity less than the critical value; Thirdly, putting the critical parameters generation into the attenuation formula, the safe distance in different gas accumulation and roadway conditions are calculated by the nonlinear equation root dichotomy procedure in MATLAB; Finally, the quantity-distance table and the safe distance nomograph, through which we can get the safe distance quickly in practice, are successfully made on the basis of the calculation.At last, taking the 3.12 large gas explosion occurred in Ren Lou Coal Mine, Wan Bei Coal Group and the gas explosion experiment in Lake Lynn Mine for example, the paper analyzes the failure behavior and verifies the attenuation law of shock wave in actual roadways;Meanwhile, the general law of the gas source, the ignition source, the ventilation system and the accident spot on gas explosion are gained by stastics analysis on the serious gas and especially serious gas explosion accident in our countries’ coal mines.