Dynamic Response Analysis of Underground Pipe Gallery under Gas Explosion

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.