管廊燃气爆炸载荷特征及作用效应研究

Gas Explosion Study on Load Characteristics and Action Effect in Pipe Gallery

管廊燃气爆炸效应严重危及城市发展和社会生活稳定,研究燃气爆炸冲击波荷载特征及作用效应对管廊结构优化设计具有重要指导价值。设计开展了城市管廊燃气爆炸相似模型试验研究,分析了不同甲烷浓度情况下燃气爆炸冲击波时程曲线与压力分布特征。理论推导了燃气爆炸荷载作用下结构顶板位移响应峰值计算公式,并结合模型试验结果和数值仿真结果对位移响应理论计算结果进行了验证。结果表明:甲烷浓度为9.5%时,燃气爆炸超压峰值高于10%浓度,在此情况下,超压峰值大小取决于燃气爆炸时的浓度条件;在试验条件下燃气爆炸超压时程曲线升压时长为500~700 ms,超压作用时间约1500 ms,爆炸超压作用时间与模型大小有直接关系;仓内各测点超压峰值分布均匀,可近似看作时变均布荷载。研究结果反映出,理论推导给出的顶板位移响应计算公式切实有效,可用于计算燃气爆炸荷载作用下的顶板最大位移值。

The gas explosion effect of pipe galleries seriously endangers urban development and social life stability.Studying the load characteristics and effect of gas explosion has guided significance of the optimal design of pipe gallery structure.The similarity model test of gas explosion in urban pipe gallery was designed,and the time history curve and pressure distribution characteristics of gas explosion shock wave under different methane concentration were analyzed.The calculation formula of the peak displacement response of the structural roof under the action of the gas explosion load is theoretically deduced,and the theoretical calculation results of the displacement response are verified by combining the model experiment results and numerical simulation results.The results show that when the concentration of methane is 9.5%,the peak overpressure of gas explosion is higher than the concentration of 10%.In this case,the peak value of overpressure depends on the concentration conditions of gas explosion.Under the test conditions,the size of the overpressure peak depends on the concentration conditions of the gas explosion.The gas explosion overpressure time-history curve has a boosting time of 500~700 ms,and the overpressure action time is about 1500 ms,the action time of explosion overpressure is directly related to the size of the model.The peak overpressure at each measuring point is evenly distributed,which can be approximated as a time-varying uniform load.The study results show that the given calculation formula for roof displacement response is effective and can be used to calculate the roof′s maximum displacement under the action of gas explosion loads.