Safe vibration velocity of directly buried pressure pipeline under blasting P wave

With the continuous development of urban underground space in China, safety problems between urban underground pipelines and underground engineering construction that are in active service are constantly emerging. As an important way of excavating engineering rock and soil mass, blasting has a particularly prominent impact on pressure pipelines due to its harmful seismic effect. It is of great significance to study the vibration damage effect of the pressure pipeline under the excavation blasting earthquake to guide the safety production of the adjacent pipeline blasting construction and the safety design of the pressure pipeline under the influence of adverse factors such as blasting vibration. Based on the above research requirements, the stress characteristics of a thin-walled pipe with uniform internal pressure under an incident P-wave caused by blasting are first analyzed. The stress analytical calculation model under the seismic wave of pressure pipeline blasting is then established by quasi-static analysis and superposition principle. Based on the yield characteristics of pressure pipeline materials and the Tresca yield theory, a safety criterion calculation model for the vibration velocity of pressure pipeline under P-wave blasting is established. Combined with two engineering cases of a directly buried pressure thin-walled pipeline under explosion, the calculation model is verified. Results show that before the application of blasting load, the pipeline is only subjected to uniform internal pressure with initial axial and tangential stresses. After blasting, the pipeline is subjected to both internal pressure and blasting seismic P-wave load. Results reveal that the peak stress of the pipeline decreases with the increase of the incident angle. Moreover, the tensile failure mainly occurs at normal incidence, and the tangential failure mainly occurs at the total reflection. The vibration velocity of the safety control of the pressure pipeline increases with the increase of the incident angle. In the actual project, according to the actual situation of the internal pressure of the pipeline, the smaller value is selected as the safety control value.