Mechanical Behavior of Sandy Soils Under Different Moisture Contents Using UU Triaxial Tests
The objective of this study was to determine the influence of moisture variation on the shear strength and stress–strain response of sandy soils subjected to different confinement levels. The applied methods followed a quantitative, applied, and quasi-experimental approach using reconstituted cylindrical specimens measuring 7.26 cm in diameter and 14.52 cm in height. Moisture contents of 0%, 2.5%, 5%, 7.5%, and 10% were evaluated under confining pressures ranging from 50 to 200 kPa. The findings demonstrated that the mechanical response strongly depends on both moisture content and confinement conditions. Under dry conditions, shear strength increased considerably with higher confinement levels due to greater interparticle friction and granular interlocking. At 2.5% moisture content, strength improved because capillary suction effects generated apparent cohesion. The maximum shear strength value, 870.77 kPa, was obtained at 7.5% moisture content, where capillary suction and granular densification reached an optimal balance. In contrast, at 10% moisture content, strength decreased due to excess pore water, which reduced effective stresses and interparticle friction. The novelty of this study lies in identifying the optimal moisture content that maximizes the shear strength of sandy soils under UU triaxial testing conditions.