Variation law of infrasound leakage sound source of Urban PE gas pipeline

To explore the infrasound leakage detection technology for urban buried medium-and low-pressure Polyethylene pipelines and master the infrasound source characteristics of PE pipeline leakage, comparative analyses were conducted of the changes and laws of parameters such as the infrasonic pressure field, sound pressure level, and total plane wave power density in PE gas pipelines under leakage and non-leakage conditions via numerical simulations and laboratory tests. The results show that: once a pipeline leaks, the amplitudes of parameters including the sound pressure field, sound pressure level, and total plane wave power density of the infrasound source signal increase, with peaks appearing in the frequency domains of 0~2Hz and 10~13Hz respectively. Subsequently, the total plane wave power density decreases rapidly within these two peak frequency bands, the energy loss increases sharply, and the frequency domains of the sound pressure field and sound pressure level exhibit the characteristic of periodic slow decrease. In contrast, under the non-leakage condition, the amplitudes of the above three characteristic parameters are relatively stable with almost no fluctuation, which provides favorable data support for judging pipeline leakage. Additionally, finite element analysis was introduced to establish a calculation model for the infrasound field, and this model was well verified in the experimental pipeline. This research offers foundational theoretical insights for leak detection together with monitoring in urban non-metallic gas pipelines.