IMPROVEMENTS IN NUCLEAR-DENSITY CONE PENETROMETER FOR NON-HOMOGENEOUS SOILS

摘要

In Singapore, the use of clays from marine dredging and land-based construction activities as fill for land reclamation provides a solution to the problem of disposal while turning such unwanted soils into material of economic value. A major problem with such fill is the formation of very high degree of heterogeneity in the ground. The characterization of such ground at different stages of land reclamation works poses a major challenge as many traditional in-situ tests which provide point values are based on solutions derived assuming the ground is a continuum. A major site characterization program was carried out as part of a research project. The Nuclear-Density Cone Penetrometer is employed for site investigation to measure the continuous changes in density together with other usual cone parameters. The tests have been conducted at various stages of land reclamation works. In the present paper, the problems faced in marine based investigations associated with the use of an existing Double Probe Nuclear-Density Cone Penetrometer are briefly discussed and this limitation has led to the development of a new Single Probe Nuclear-Density Cone Penetrometer which is the main focus of this paper. The wet density profiles obtained from the Single Probe Nuclear-Density Cone Penetrometer are compared with the double probe and the comparison shows a very good agreement.