Measuring the behaviour of dual row retaining walls in dry sands using centrifuge tests

Protecting coastal populations requires innovative Civil Engineering solutions, as highlighted by the 2011 Tohoku earthquake and tsunami. To this end, dual row retaining walls are being deployed along the Kochi coastline in Japan. Mechanically, how the soil-structure system resists seismic lateral loading is not well understood however. The baseline case of walls founded in dry sand is considered in this work. Dynamic centrifuge tests of dual row walls were conducted and the performance monitored using multiple techniques. The PIV technique gives wall and soil displacements and bending moments were obtained from strain gauges. Further, the horizontal dynamic earth pressures were obtained from tactile pressure sensors. The combination of techniques allows assessment of the internal measurement consistency and together advance understanding of the system behaviour. Decomposing the temporal variations rationalises the pre and post-earthquake results. This allows the overall structural behaviour to be linked to measured changes in the soil behaviour.