EFFECT OF MOISTURE CONTENT ON SOIL BEARING CAPACITY

ABSTRACT This study investigates the effect of moisture content on soil bearing capacity, with an emphasis on understanding how variations in water content influence the engineering behaviour of clay, silt, and sand soils. Laboratory tests were conducted to determine effect of moisture content, dry density, and compaction characteristics of the soil samples. The compaction results show that moisture content significantly affects soil density and, consequently, the bearing capacity. Silt achieved the highest maximum dry density at very low moisture content, while clay required higher moisture to compact effectively. Sand showed moderate behaviour, requiring some moisture for lubrication but losing strength when excessively wet. The findings reveal that increasing moisture content beyond the optimum level leads to a reduction in dry density and bearing capacity due to a rise in pore water pressure and a decrease in effective stress. The study concludes that proper moisture control is essential during construction to prevent structural failure, especially in clay and silt soils. The results show that moisture content has a significant influence on soil bearing capacity. As moisture content increases from the dry state toward the optimum moisture content (OMC), the bearing capacity of the soil increases due to improved particle lubrication and densification during compaction. However, beyond the OMC, further increases in moisture lead to a rapid reduction in bearing capacity, as excess water weakens the soil structure, reduces inter-particle friction, and increases pore-water pressure. This trend indicates that the maximum bearing capacity is achieved at or near the optimum moisture content. Recommendations are provided to guide engineers in soil handling, compaction, and foundation design. Keywords: Moisture Content, Soil Bearing Capacity, Compaction, Shear Strength, Optimum Moisture Content (OMC).