Improvement of dynamic soil properties induced by preloading verified by a field test

Presented here are the results of an elaborate field preloading study on a liquefaction-susceptible site. Preloading was applied by a temporary embankment 9 m high. Prior and after preloading, borings with standard penetration tests, cone penetration tests and geophysical studies were performed. During the process of embankment construction and demolition, settlements, excess pore pressures and vertical and horizontal stresses were recorded versus time at different locations. A partial embankment failure occurred during the preloading process. Methods are proposed and verified which predict (i) risk of failure during the construction of the preload embankment and (ii) stresses and displacements and (iii) the change in the shear wave velocity and cyclic liquefaction strength induced by the preload embankment.