The Dynamic Cone Penetrometer as a Seismic Source for Geophysical Exploration in Urban Environments

The Dynamic Cone Penetrometer (DCP) is a classic and prevalent testing device for evaluating the structural conditions of asphalt pavements in situ. The device consists of a steel rod with a conical tip; the rod guides a small mass that is manually raised and dropped, hammering the tip into the tested pavement. This study was motivated by the idea of utilising the DCP as a seismic source, and subsequently employing geophysical techniques to uncover the shear modulus of deep materials which the tip cannot reach. A seismic survey was carried out over an asphalt road wherein waves caused by a DCP drop were recorded with an array of accelerometers. A forward-interpretation technique was outlined and applied to obtain the shear modulus profile below to road’s surface down to a large depth. The resulting profile was validated by comparison against other measurements. It is concluded that the advocated idea is practical and useful, and that it should be extended to investigate the attenuation characteristics of urban infrastructures.