Dynamic Simulation and Mechanical Analysis of Large-Diameter Water Main Burst

Abstract:

Pipe burst in urban water supply networks often pose serious threats to urban operation safety. Based on the pipe burst accident at Siping-Liyang Road in Shanghai on November 16， 2017， the pipe burst was modeled and analyzed by using the finite element method（FEM） with in-situ investigation and the damaged pipeline data collected from 3D laser scanning. The effect of pipe pressure and initial crack length on the stress concentration at crack tip was studied assuming the existence of some potential cracks in the pipe. The full failure process was also simulated from the initial crack to pipe burst by dynamic analysis. The results show that the stress concentration at crack tip grows as water pressure increases， the rate of which varies with crack length. The critical water pressure at crack tip failure decreases as crack length increases sharply. The central angle of initial crack length is evaluated to be more than 26° through the monitoring the data of pipe pressure around. The pipe failure simulation shows that the pipe shards rotate towards the pipe top with the development of crack and finally break along the pipe while the penetrating crack forms. The rotation and outward translation of the shards is considerably large due to external loads and internal pressure， and thus the burst of pipe causes great damage instantaneously.