Abstract

In order to solve the problem of subsurface cavities in urban areas, industry, government and academia carried out collaborative research over 2018-2020. In this joint research, analysis of existing cavity data, laboratory model experiments, numerical analysis, and full-scale field test, monitoring of the cavity in the road, etc. were conducted. In this study, a full-scale test road was constructed with artificial cavities installed to evaluate the risk of collapse in consideration of the road structure. A series of plate loading tests and falling weight deflectometer tests was conducted on the road surface above a cavity to understand the cavity behaviour. A surface wave survey was also conducted to evaluate the wave propagation on and around cavities. It was found to be reasonable to evaluate the collapse risk of subsurface cavities by the ratio of depth and width of cavities, in which the thickness of the pavement should be excluded from the depth.