In-situ measurement of wet density and natural water content with RI-Cone penetrometers

The development of two types of radioisotope cone penetrometers (RI-Cones) is described. They are Neutron-Moisture Cone penetrometer (NM-Cone) that can detect the natural water content of soils and Nuclear-Density Cone penetrometer (ND-Cone) that can measure the wet density of soils together with the conventional triple components of CPT. These cone penetrometers have been successfully applied to actual site investigation at various locations in the world. In-situ performance of RI-Cones is presented for two clayey deposits and two sandy deposits. For all sites, the natural water content, wn and the wet density, ρt profiles measured with RI-Cones have been compared with the data obtained from laboratory tests carried out on undisturbed samples. On the basis of the fact that they show a very good agreement for both clay and sand deposits, RI-Cones are found to be versatile tools for subsoil investigation.