Influence of Grain Sizes on Undrained Strength of Sand Mixtures

Abstract

Sand is known as the main material in land reclamation works to develop and widen an area. It is important for the Geotechnical Engineer to ensure the sand used can accommodate the burden imposed from the structures to be built on it. Previous researchers have conducted studies on the strength of sand, whether focusing on the sand itself or with the presence of fines. However, the study of sand grain size effects in sand mixtures in affecting sand behavior is extremely limited. The sizes and angularity of the sand particle are believed to contribute to the behavior of sand mixtures soil. Hence, the study to investigate the effect of sand grain size on sand mixtures in term of undrained strength is being carried out. The sand was sieved to coarse sand, medium sand and fine sand then each size was mixed with kaolin at 0 %, 20 % and 40 %. The undrained strength was obtained from triaxial test on undrained condition. As a result, it is found that the maximum deviator stress, qmax increases with the decrease of fines (kaolin) content. On the other hand, at the same fines content, increased of sand size leads to the increased of qmax, which means the increased of undrained shear strength. In addition, the angular shape of sand particle was thought to contribute to the high value of undrained shear strength for the sand mixtures.