Study on the Influence Mechanism of Sample Preparation Method on the Shear Strength of Silty Soil

Abstract

During the compaction of silty soil subgrade, different filling methods are adopted, which will significantly impact the subgrade performance, but few studies have been applied to quantify this influence. To explore the influence mechanism of dry density and sample preparation method (compaction and static compression method) on the shear strength of silty soil, the consolidated undrained shear test (CU test), dynamic triaxial test, and nuclear magnetic resonance microscopic test on silty soil were carried out in this study. The test results show that the shear strength of the sample is positively correlated with the dry density. The influence of the sample preparation method on shear strength is mainly reflected in the cohesion. The pore size distributions obtained by different sample preparation methods had smaller differences before the CU test. However, significant differences were observed after the CU test, indicating that the influence of the sample preparation method on the shear strength of the sample is not on the initial pore distribution but on the residual stress and overall uniformity. The dynamic triaxial tests show that a differential settlement may occur when multiple sample preparation (soil-filling method in subgrade practice) methods are adopted.