Measurement of wave‐induced pressures and stresses in a sandbed

The effects of water‐wave loading on the pressure and stress distributions within a sandbed are examined experimentally in a laboratory wave tank. Total stresses and pore water pressures are measured directly in the sandbed. A simple, rigid‐bed model capable of predicting stresses and pressures is compared to the data obtained in the test program. The model'combines total stresses with pore water pressures to obtain effective stresses. The results of this study show that wave loadings on a saturated sandbed alter the effective stress state throughout the bed. Cyclic stress ratios are maximum at the sediment‐water interface, and for the test conditions considered, have a maximum value of 0.20, although higher values are possible. Bed displacements are shown to be small, thus verifying the assumption of rigid bed behavior for sand.