Dynamic buckling response of buried X70 steel pipe with bolted flange connection under two-charge explosion loads

It is of great significance to investigate the dynamic response of pipes under blasting loads for the operation, assessment, and repair of pipes. However, there are few studies available on the dynamic buckling response of pipes under multiple explosion loads. In the present study, pipe-soil coupling 3-D models are established to investigate the dynamic buckling response of X70 steel pipe with bolted flange connection (BFC) under two-charge explosion loads (Charge A lied on the ground surface and Charge B lied in the soil). The main influencing factors are also discussed, including explosion mode, internal pressure, interval time, mass ratio of charges, and diameter-to-thickness ratio (D/t ratio). When Charges A and B were exploded simultaneously, it is found that the non-pressurized X70 pipe produced more significant cross-sectional deformation than in one-point explosion (Charge A or B). Increasing D/t ratio is advantageous for the anti-explosion of the pipe with BFC. Suitable internal pressure can effectively prevent the buckling deformation of the pipe. Compared with the common straight pipe, BFC system can effectively decrease the local buckling deformation and improve the anti-explosion ability of the pipe due to its higher local stiffness and energy absorption.