A Comparison between the Dynamic Behaviour of Flexible Dual Row Walls Founded in Dry and Liquefiable Sands

抄録

The 2011 Tōhoku earthquake and Tsunami event devastated large parts of the Japanese coastline, causing widespread damage to infrastructure and claiming many human lives. The dual row wall concept is potentially a robust and efficient sea wall design. However, loss of soil strength and stiffness from earthquake induced liquefaction is a prospective design concern. Evaluating the resilience of the dual row system to earthquake loading is a complicated soil structure interaction problem even when the walls are founded in dry ground. Further, soil liquefaction fundamentally changes the seismic wall and soil response. Centrifuge modelling provides an avenue to explore the dynamic behaviour. Dynamic testing of small scale centrifuge models of the dual row wall systems, founded in dry and liquefiable sands is detailed. Recorded wall and soil accelerations are considered and the impact of excess pore pressure generation on the shear stress transmission highlighted. Observable changes in the dynamic shear stress strain behaviour of the soil rationalise the system responses. A modified approach to inferring the wall displacements from the accelerations and discrete displacement measurements is discussed. Consistency between the results is verified and the differing displacement modes obtained are considered in the context of the overall soil behaviour.