In order to investigate the working mechanism of composite foundation with rigid piles
two tests of composite foundation with 9 piles were conducted. In these tests
pressure cells were embedded in the soil to measure the vertical stresses at different depths
whereas stress gauges with vibrating strings were installed in the piles to measure their axial forces
which can be further used to estimate the pile shaft friction. The load was applied step by step and the stresses in the soil arid axial forces in the piles were measured for each load step. The test results show the entire process of load transmission; and they can provide useful information for the designer in understanding the bearing characteristics of this type of composite foundation.