Effect of initial fabric on the undrained response of clean Chlef sand

Different soil reconstitution methods lead to samples with different initial structure. This article presents a laboratory investigation which aims to study the influence of initial fabric of specimens on the undrained behaviour of clean Chlef sand subjected to triaxial compression tests. The samples tested were prepared at three level of relative densities using different deposition methods, i.e., the layered dry deposition (LDD), the tapped funnel deposition (TFD), the water deposition (WD) and the moist deposition (MD), and they were consolidated under different confining pressures. In order to evaluate the soil fabric, an analysis using X-ray µCT was conducted on three loose samples after soil reconstitution and before triaxial testing. It was found that the void ratio of the sample prepared by the MD method is slightly higher than that of samples reconstituted by the two others methods (TFD and WD). The triaxial results showed that the resulting fabric affects the behaviour of the sand. It was found that the effect of initial fabric is more pronounced at large strain where the specimens prepared by the MD method always present the lowest resistance. These findings, especially those found at loose state, are in agreement with those obtained from µCT.