The Effect of Moisture Content at Compaction and Grain Size Distribution on the Shear Strength of Unsaturated Soils

Abstract

The soil moisture content at shearing and other factors, including dry density and grain size, influence its shear strength. This study investigated the effect of moisture content at compaction and grain size distribution on the unsaturated soil shear strength. Triaxial compression tests were performed in the laboratory using the modified triaxial apparatus on silica sands No. 3 and 6 without fines and with 20% fines to explore the unsaturated soil shear strength characteristics. Test samples were compacted and sheared at various combinations of the soil’s optimum and residual moisture content. The analysis of the triaxial compression test results shows that moisture content at compaction and the grain size distribution influence the unsaturated soil shear strength. The test samples compacted at optimum moisture content showed higher peak shear strength when sheared at residual moisture content. Further, test results show that the test samples of soil without fines, when compacted at residual moisture content, show higher peak shear strength at optimum moisture content. The finding of this study endorses considering the moisture content at compaction for the geotechnical design of structures while predicting the soil shear strength.

Thermal Conductivity and Shear Strength in Root-Reinforced Silty Clay: An Analysis of Asteraceae Plants from Taihang Mountain

“…Despite an abundance of studies on the thermal dynamics of silty clay, a discernible focus is evident: investigations predominantly target singular soil types, often overlooking the interplay of biology, particularly plant root systems [15][16][17][18][19]. Moreover, extant literature is replete with experiments, often sidelining methodical theoretical analyses [20][21][22][23][24][25][26][27]. For instance, a preponderance of studies have been noted to quantify thermal conductivity through mere experimental measurements, abstaining from dissecting influences like pore configurations, seepage conditions, or stress states.…”