Modeling Potential Liquefaction during an Earthquake under a Breakwater with PM4Sand

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Abstract

The stability of breakwaters in seismically active areas is not always guaranteed. A new approach to model a breakwater subjected to an earthquake is with PM4Sand. The goal of this research is to find if breakwaters subjected to earthquakes can be correctly modelled with PM4Sand.
To investigate PM4Sand a breakwater subjected to an earthquake on centrifuge scale is modelled in Plaxis. The soils of the centrifuge test are modelled with PM4Sand and UBCSand. After calibrating the soil parameters and incorporating the proper earthquake signal results are generated and compared. The investigated results focus on the settlements of the caisson, deformations of the breakwater and generated Excess Pore Water Pressures underneath the breakwater due to the earthquake. Comparing the results from the numerical models with the centrifuge test result show that both the UBCSand model and PM4Sand can give comparable results for the settlements and deformations. However, both UBCSand and PM4Sand were not able to give the correct EPWP development underneath the breakwater.
Due to the incorrect behaviour of the EPWP underneath the breakwater resulting from the numerical models, this research is not able to conclude that PM4Sand can be used for modelling breakwaters subjected to earthquakes. Further research is needed to investigate the development of EPWP underneath the breakwater during an earthquake. Focus points of future research can be: the influence of the amplitude of an earthquake signal on the EPWP, the influence of modelling a centrifuge test on the behaviour of the EPWP and the influence of the initial static shear stress on the EPWP development.