Development of free fall cone penetration testing system

Abstract

For the rigorous design of offshore structures, the geotechnical characteristics of the seabed ground should be rigorously investigated, in the deep water, seabed ground surveys are complex equipment and costly. Free fall type ground survey equipment that can acquire a simple and comparatively accurate ground is developed when only the characteristic investigation of the shallow depth ground such as the submarine pipeline, the submarine cable burial is the main concern. In this study, FFCPT was developed. Based on behavior results of numerical model simulation for FFCPT, it was manufactured. Water depth was obtained using pressure sensor and penetrated depth was estimated by the double integration of acceleration signal. In addition, we can veri-fy vertical penetration at real field test of FFCPT using 2axis of inclinometer. So, the results of the seabed type offshore CPTu experiment and the developed model were compared and the performance was evaluated.