瓦斯爆炸对隧道衬砌应力影响的数值模拟

Numerical Simulation of the Influence of Gas Explosion over Lining Stress of Tunnel

以云南省某隧道瓦斯爆炸事故为背景,基于等效爆源理论对隧道内的瓦斯爆炸进行量化,采用ANSYS/LS-DYNA有限元分析软件中Arbitrary Lagrangian-Eulerian(ALE)算法,建立隧道内瓦斯爆炸的流固耦合模型,选用*MAT_JOHNSON_HOLMQUIST_CONCRETE(JHC)材料模型模拟衬砌,分析瓦斯爆炸冲击波传播特征及其对隧道衬砌应力的影响.结果表明:(1)爆炸后隧道内冲击波压强会瞬间增大并持续一段时间;(2)爆炸后的冲击波受到衬砌和围岩的约束,会在隧道内循环发生无规则反射,导致冲击波大幅度增强,并使隧道内的流场复杂化,减缓冲击波强度衰减的时间,且在衬砌墙角和底板处反射效应最强;(3)爆炸后衬砌的有效应力达到最大值后迅速衰减,但是在衰减过程中反复波动,加剧了爆炸对衬砌的破坏.

In this paper,the quantitative research of gas explosion is carried out on a tunnel accident in Yunnan Province based on equivalent explosive energy theory,and the fluid-solid coupling model of gas explosion in tunnel is established by means of Arbitrary Lagrangian-Eulerian(ALE)algorithm of ANSYS/LS-DYNA software,the tunnel lining is simulated by*MAT_JOHNSON_HOLMQUIST_CONCRETE(JHC)model,the characteristics of explosive shock wave are studied and its effects on lining stress of tunnel are analyzed.Results show that:(1)After the explosion,the pressure of shock wave in the tunnel increases instantly and lasts for a period of time;(2)The shock wave after the explosion is constrained by the lining and surrounding rock,and will circulate irregularly in the tunnel,causing the shock wave to be greatly enhanced,complicating the flow field in the tunnel,and reducing the time for the strength of the shock wave to decay,the reflection effect is strongest at the lining of the corner and bottomplate;and(3)After the explosion,the effective stress of the lining will reach the maximum value,and then the effective stress will decay rapidly,but it will fluctuate repeatedly during the attenuation process,which intensifies the damage to the lining by the explosion.