Simulating floodwater movement in pavements for developing post-flooding time-depth-damage functions

Flooding has caused severe damage to civil infrastructure worldwide. Roadway pavements are one of the infrastructures most affected by flooding, however, quantification of post-flooding pavement damage has not received attention until recently. There remains a gap to advance knowledge on how floodwater moves inside pavements and, consequently, how it will impact post-flooding pavement damage. This study adopted finite element seepage modeling to observe floodwater movement in three different pavements, each under three flood scenarios. Laboratory testing is conducted to validate the accuracy of the model. It is concluded that both the finite element seepage modeling and laboratory testing show similar post-flooding weakening and recovery behavior in pavements. The recovery phase is much longer than the weakening phase, due to the hysteretic nature of soil moisture related to suction. The base layer loses stiffness drastically during the weakening phase, more than any studied subgrade materials. The improved understanding reported here can enhance the development of time-depth-damage functions for post-flooding pavements. It will enable the quantification of post-flooding damage and thus facilitate estimation of flood induced economic losses in practices.

Automated summary

Flooding has caused significant damage to civil infrastructure globally, particularly roadway pavements. However, quantification of post-flooding pavement damage has only recently received attention, and there is still a knowledge gap regarding how floodwater moves within pavements and how it impacts pavement damage. This study used finite element seepage modeling and laboratory testing to observe floodwater movement and found that pavements exhibit similar post-flooding weakening and recovery behavior. The study also highlighted the importance of understanding the time-depth-damage relationships for post-flooding pavements to estimate economic losses caused by floods.