AN EXPERIMENTAL STUDY OF LIQUEFACTION OF SATURATED SANDS

Abstract

Loose saturated sand was placed in a rigid box, covered with an impervious membrane, and subjected to horizontal vibration while a surcharge was applied on the membrane. The pore water pressure measured at various depths during vibration showed that the process leading to a completely liquefied state consisted of two stages : (1) a period in which the pore pressure at different depths increased uniformly and simultaneously while the sand remained stable, and (2) a very rapid rise in the pore water pressure reaching the value approximately equal to the total stress.The second stage (termed "sudden liquefaction" process) occurred when the effective stress was reduced to a certain value as a result of the first stage (termed "initial compaction" process). The critical effective stress immediately before the sudden liquefaction increased with an increase in the applied acceleration, and the duration of the initial compaction process increased with increasing surcharge and with decreasing acceleration.