Influence of fine content on undrained monotonic behavior of carbonate sand

Abstract

The behavior of carbonate sand is different from that of siliceous sand in terms of high compressibility and crushability, specific particle shape, and physical properties. Thus, investigating the behavior of these soils is of great importance because of their prevalence in coastal areas. Nevertheless, a few studies have considered the presence of fines in the mixture with carbonate sand. The present study explores the influence of non-plastic fines on the undrained monotonic behavior of Bushehr carbonate sand. For this purpose, 30 undrained monotonic triaxial tests were performed on carbonate sand with silt ranges of 0% to 40% with two different void ratios. According to the results, the undrained shear strength of carbonate sand diminished with the addition of silt percentage up to 20%, and increased dramatically at 30% silt content. Also, the results of 40% silty sand revealed that this sample is stronger than samples with 10% and 20% silt content. By surveying the location of the phase transformation point in samples, it was observed that silt particles reduce the dilative phase. Also, confining pressure intensified the contractive phase while relative density had the opposite effect. The results showed that the effect of particle breakage is negligible in this study.