Theoretical solution of the vibration response of the buried flexible HDPE pipe under impact load induced by rock blasting

摘要

The blasting vibration load can pose great threats to the safety of urban buried pipelines. Winkler model is commonly used to simulate the soil-pipe interaction and calculate the response of the stiff pipe, but the effectiveness of the resulting for the flexible pipe is doubtable. In this study, a theoretical method based on the Winkler model and the Timoshenko beam theory is presented to calculate the effect of blasting load induced by rock blasting on the overlying flexible buried pipe, and the modified soil spring stiffness is provided for accurately calculating the vibration response of flexible high-density polyethylene (HDPE) pipe buried in the silty clay. The proposed theoretical method and modified spring stiffness are tested and calibrated against full-scale experiments and its detailed numerical modeling with ANSYS/LS-DYNA. It is indicated that the analytical method with empirical spring stiffness (from American Lifeline Alliance 2001) overestimates the vibration velocity magnitude of the HDPE pipe subjected to blasting vibration. Reducing the spring stiffness to one-tenth of the original value can provide improved calculation results for flexible HDPE pipe subjected to blasting vibration.