Dynamic Response Analysis of Underground Pipe Gallery under Gas Explosion
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摘要: 在燃气通过地下管廊输送过程中,若燃气泄漏进入管廊内部并引起爆炸将会产生严重的后果。以平潭综合试验区环岛路管线工程为背景,借助LS-DYNA非线性动力分析有限元软件,基于流固耦合和ALE多物质算法,建立地下空间燃气爆炸数值计算模型,探讨管廊内燃气爆炸过程中爆炸冲击波对管廊结构的影响。数值计算结果表明:在爆炸过程中,超压峰值从爆源中心转移到波阵面上,导致爆源附近压力低于波阵面压力,爆源附近形成负压区;爆炸荷载作用下,燃气仓内距离爆源最近的内墙上的测点超压值最大,在t=7.8 ms时达到最大值为18.65 MPa,且在t=10 ms左右时,位移和速度达到最大值,分别为10.47 mm、3.303 m/s;气体爆炸后,管廊燃气仓内墙正负压振荡时间持续较长,振动现象最为明显,最易发生破坏。Abstract: Many factors can cause natural gas explosions, and it will lead to serious structural damages and human injures.This study is focused on the leakage of natural gas from underground pipe gallery.A case study has been made in a project of the circular island road in Pingtan comprehensive test.An underground explosion was modeled by use of the fluid-solid coupling and multi-material ALE algorithm in finite element software LS-DYNA.On this basis, the influence of explosion shock wave on the surrounding structure was discussed.Numerical results show that, during the whole process of the explosion, the overpressure transferred from explosion source center to the wave front, leading to the lower pressure in the explosion source compared to the wave front and the formation of a negative pressure zone near the explosion source.The overpressure value of point which is on the internal wall closest to the explosion source in the gas cabin is larger than that of other points.The maximum overpressure is 18.65 MPa at t=7.8 ms.At t=10 ms, the displacement and velocity reach their own maximum values of 10.47 mm and 3.303 m/s, respectively.Explosion in the gas cabin, interior wall experiences positive and negative pressure oscillation with long duration, the vibration phenomenon is most obvious and the structure is easy to be failure.
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表 1 土壤材料参数
Table 1. Parameters of soil material
Material Thickness/
cmDensity/
(g·cm-3)Cohesion/
kPaInternal frictionangle /(°) Elastic modulus/MPa Poisson'sratio Plain fill 130 1.8 6 10 4.2 0.30 Fully weathered granite 210 1.9 20 25 20 0.24 Sandy weathered granite 620 2.0 30 32 54000 0.21 表 2 混凝土材料参数
Table 2. Parameters of concrete
Density/(g·cm-3) Elastic modulus/GPa Poisson's ratio Yield strength/MPa Shear modulus/GPa 2.5 30 0.22 33.8 12.5 -
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