Earthquake-Induced Liquefaction of Confined Soil Zones: A Centrifuge Study

Abstract

Abstract : Reported here are data from four dynamic centrifuge tests conducted on model embankments with confined liquefiable soil layers. The model embankments were constructed with a steeper slope on one side to give a factor of safety similar to that of the down stream slope of an equivalent embankment with outward seepage. These liquefiable zones were inclined and were located on the steeper slope side of the model embankment. In the first centrifuge test LEG-1 the liquefiable layer of sand was inclined but the excess pore pressures dissipated rapidly. There was some settlement of the crest and slipping of the down stream slope. In the subsequent centrifuge tests LEG-2 to LEG-4 the loose layer was confined by placing a thin impermeable rock flour layer at its interface with denser sections. In these tests the excess pore pressures were sustained for much longer time. The acceleration traces recorded on the down stream slope showed significant peak accelerations in one direction indicating slipping of this slope.