Effects of Soil-Resistance Damping on Wave-Induced Pore Pressure Accumulation around a Composite Breakwater

摘要

It is important to consider the potential instability of the seabed from the accumulation of wave-induced pore pressure in the design of a composite breakwater because the pore pressure within the seabed can build up considerably under wave loading, which can eventually lead to a sharp decrease in its effective stress. Because of the importance in practical engineering, many theoretical models have been developed to evaluate the magnitude and distribution of residual pore pressure. However, most of these studies treat the soil skeleton as an invariant medium, which ignores the damping of the soil strength from the reduction in the effective stress. In this study, a two-dimensional poroelastoplastic model, in which the influence of the reduction of effective stress on soil strength was considered, is proposed for investigating the accumulation of pore pressure around a composite breakwater and its effect on soil characteristics. The simulation results show that liquefaction is likely to occur around the toe of the breakwater because of the accumulation of pore pressure at that point. The liquefaction leads to a decrease in soil resistance, which has a great effect on the development of the residual pore pressure. Analysis shows that the development of residual pore pressure is also greatly affected by both the wave height and soil permeability. The simulation demonstrates that if the decrease in soil resistance is not considered, the soil liquefaction depth will be overestimated.