Soil improvement with laponite: effects on soil-structure interaction in liquefiable sands

This paper investigates the effects of laponite treatment as a mitigation technique against seismically induced soil liquefaction and its influence on soil-structure interaction. Firstly, undrained cyclic triaxial tests are conducted on clean and laponite-treated Hostun sands. The tests confirm that laponite could enhance the resistance of the treated sand against liquefaction and that the constitutive model PM4Sand is able to capture the main aspects of the dynamic behavior of both clean and laponite-treated Hostun sands, by adjusting the relevant constitutive parameters. Then, two-dimensional plane-strain finite element models are constructed using OpenSees and PM4Sand based on the centrifuge tests involving two schemes of laponite treatment. The numerical results match well with the centrifuge test data, thus verifying the validity of the numerical soil-structure systems. Finally, the numerical models are re-configured to test the effects of laponite treatment on the soil-structure interaction of a shallow buried tunnel, a surface structure, and a combination of the two in liquefiable soils.