102 / 2025-04-24 12:56:04

Prototype-Scale Experiments on the Processes and Detection of Coastal Internal Erosion, Cavity Formation and Collapse beneath Asphalt Pavement

Cavity collapse caused by internal erosion of backfilling sand has occurred frequently at
the back sides of coastal structures such as seawalls and quaywalls worldwide. To prevent such
geohazards, it is crucial to detect cavities under the pavement at an early stage. This requires an
understanding of the processes of cavity formation, development, and collapse, while considering
the pavement structure. In this study, based on the above background, prototype-scale experiments
were conducted to investigate how different types of backfilling sand and pavement thickness
influence these processes beneath asphalt pavement under a water level rise, and how these factors
affect the accuracy of ground-penetrating radar (GPR) in detecting a cavity under the pavement.
The results revealed the processes and mechanisms relevant to cavity formation, development and
collapse beneath the asphalt pavement. Additionally, both the backfilling sand types and the
pavement (i.e., asphalt layer) thickness significantly affected the cavity detection depth of the GPR.