Axial Deformation Behavior of Precompressed Coral Sand under Repeated Impacts

Abstract

Yang, J.; Wang, J.; Dong, L., and Fan, P., 2022. Axial deformation behavior of precompressed coral sand under repeated impacts. Journal of Coastal Research, 38(3), 592–602. Coconut Creek (Florida), ISSN 0749-0208. To investigate the subsidence behavior of backfill foundation under the disturbance of repeated landing of planes, a series of one-dimensional tests under repeated impacts were conducted on precompressed crushed coral sand with a variety of grading and relative densities. For each sample, the impacts (amplitude 600 kPa, frequency 5 Hz) were loaded three times in cluster form (lasting 6 s, one hour apart), while the static stress (200 kPa) was maintained continuously for 4 h. The axial deformations of the samples were recorded, and a comparative study was conducted by referencing the results of silica sand samples under the same conditions and coral sand samples under static loadings. The test results indicate that compared with silica sand, coral sand has a much larger total deformation, which is mainly influenced by the relative density, gradation, and order of impacts. By analyzing the results, it can be concluded that the deformation of coral sand has a greater plastic component and decreases faster than that of silica sand under repeated disturbances, and the total deformation and proportion of irreversible deformation decrease with increasing relative density. The influence of initial grading on the particle breakage index is more significant than the relative density. Improving the grading of coral sand can reduce the total deformation and minimize the proportion of unrecoverable deformation.