The potential use of GPR in the exploration for riprap layers in tidal flat embankment

Abstract

This study focuses on the use of ground penetrating radar (GPR) to delineate riprap layers in cross sections of tidal flat embankments. Foundation treatments are an important consideration in the reclamation of tidal flats and for offshore engineering in coastal areas with soft soils. Such treatments generally consist of explosive riprap fill. The bottom depth and cross-sectional shape of the riprap, which are important components of the body of an embankment, determine the effectiveness of the fill in foundation treatments and embankment stabilization efforts. Thus, identification of the bottom depth and the cross-sectional shape are important steps in the effective design and implementation of riprap fill projects. Here, we focus on a case study of a tidal flat embankment in the Zhejiang area. A comparison of the dielectric properties of a riprap layer and its surrounding soils indicates that this layer can be detected using GPR. We also present new drillhole-verified radar wave propagation velocity data for different materials obtained in this study. The velocity analysis enabled the reconstruction of the cross-section of riprap using GPR profiles. This study indicates that effective and economic riprap detection can be achieved by GPR with additional corroboration from only a few drillholes.