Seismic Performance and Seismic Risk Assessment of a Sheet-pile Retaining Wall Subjected to Liquefaction-induced Lateral Spreading

Earthquakes may trigger liquefaction in saturated coarse granular soils, causing significant lateral deformations and posing a risk to retaining walls, especially in waterfront areas. To systematically investigate the impact of sand liquefaction on the seismic performance and risk of sheet-pile retaining wall, this study employs a novel multi-yield surface elasto-plastic constitutive model to simulate the liquefaction characteristics of saturated sandy soils during earthquakes. The dynamic coupling effect between pore water and soil particles is systematically considered, and a Finite Element (FE) framework for a sheet-pile retaining wall is created based on a centrifuge test configuration. The accuracy and effectiveness of the soil constitutive model and the FE framework are validated by matching the liquefaction strength curve of the Ottawa sand and centrifuge test results. A total of 100 ground motion records are selected as the base input to develop seismic fragility curves and seismic risk curves of the calibrated sheet-pile retaining wall model subjected to liquefaction-induced lateral spreading. In addition, the cumulative absolute velocity (CAV) is identified as the optimal seismic intensity parameter based on the effectiveness, correlation, practicality, and proficiency. Ultimately, the influence of soil permeability on the seismic performance and seismic risk of the sheet-pile retaining wall is analyzed within the probabilistic framework. Overall, the research outcome provides meaningful insights into the seismic design and mitigation measures of equivalent sheet-pile retaining structures.