Seismic Performance of Underground Water Pipelines

Throughout previous earthquakes, underground pipelines system undergoes big damages led to serious impacts. Therefore, the parameters that affect the behaviour of underground pipelines under seismic load have been studied. Three tests were carried out utilising a shaking table for the buried pipe model in dry case and saturated case. Cohesionless soil was utilised as a foundation and backfill for the pipe model. Gravel (filter) is used as a first layer at the base of container. UPVC pipe with a diameter of 50 mm was used. The dynamic behaviour of buried pipe is evaluated in terms of vertical displacement (settlement), acceleration response and dynamic soil pressure. Also includes the effect of the gravel with certain thickness under pipes in terms of time history of acceleration, vertical displacement, and dynamic soil pressure. The results showed the amplification occurred at the top surface of pipe model due to amplified occurred with increasing the thickness of layers. For this reason, the design of underground pipelines system requires a big care for the decision-maker. As well as attenuation occurred in seismic waves with increasing depth of layers in the saturated case. Due to liquefaction phenomenon which leads to reduced shear strength of soil as a result accumulation of excess pore water pressure.