Influence of Initial Conditions on Liquefaction Resistance of Sandy Soil from Chlef region in Northern Algeria

Two strong earthquakes occurred in the region of Chlef (north western part of Algeria) during the last century. From the geological context, there were several great masses of sandy soil ejections on the ground surface level and severe damages to civil and hydraulic structures. These damages were due to the soil liquefaction phenomenon. The objective of this paper is to study the resistance to static and cyclic liquefaction of Chlef sand through triaxial tests with focus on the effect of the initial state. For this purpose, a series of undrained monotonic and cyclic triaxial tests were carried out on saturated silty sand at two initial relative densities (Dr = 29 and 80 %). The initial confining pressure was kept at 200 kPa. Moist tamping and dry funnel Pluviation were used to prepare sand specimens. Test results indicated that the monotonic and cyclic resistance of soil mainly depends on initial conditions. Samples prepared by dry funnel Pluviation method have a greater resistance to liquefaction while those by moist tamping have been found to be potentially liquefiable. Further, liquefaction resistance increases with increase in initial relative density and confining pressure.