Dynamic behavior and failure of buried gas pipeline considering the pipe connection form subjected to blasting seismic waves

To ensure the safety of gas pipelines during tunnel blasting excavation, it is of vital significance to investigate the dynamic response of buried gas pipelines under blasting vibration. Based on a great number of engineering examples, a representative buried gas pipeline with a diameter of 1 m and a wall thickness of 10 cm in the urban area was taken as the research object, and a full-scale buried gas pipeline blasting experiment on basis of vibration monitoring and dynamic strain monitoring was designed and implemented Next, 3D numerical models were established to analyze the response characteristics of the buried gas pipeline based on the field experiment, and the reliability of the numerical model was verified by the field monitoring data. Considering the influence of pipeline connection form, the numerical calculation models of the buried gas pipelines with bolted flange joints were established under different blasting scaled distances to supplement the field experiment. The dynamic response characteristics of the pipeline without interface and pipeline with bolted flange joints were further analyzed, and the dynamic response characteristics of bolted flange joints were discussed emphatically. At last, based on the failure mode of pipeline connection and the results of dynamic strain analysis of pipeline in field experiment, the safety evaluation of pipeline with bolted flange joints and pipeline without interface was comprehensively proposed. By comparing the safety control vibration velocity of pipeline with bolted flange joints and pipeline without interface, it is concluded that the flange bolt connection is vulnerable to the harmful effect of blasting vibration and the safety evaluation of pipeline considering bolted flange connection is more reasonable.