Effects of Water Content on Unconfined Compressive Strength of Clay

Abstract

The most significant index property of clay in the natural state is consistency. The water content has an extreme influence on consistency. At low water, content clay behaves more like a solid, but at high water content clay and water may flow like a viscous fluid. Depending on water content, the consistency can qualitatively be expressed as solid, semisolid, plastic, and liquid. Quantitatively the consistency can be expressed by the unconfined compressive strength (qu). In this research, the effects of water content on the unconfined confined compressive strength of two different clays are investigated. The samples, clay-1 is collected from Jashore, Bangladesh, and clay-2 is collected from Ashulia, Bangladesh. The clay-1 and clay-2 have a liquid limit and plastic limit of 33.0, 44.0, and 22.5, 26.0 respectively. The laboratory compaction tests revealed that the maximum dry unit weight of clay-1 is 17.20 kN/m3 and clay-2 is 16.16 kN/m3 . In the unconfined compressive strength tests, cylindrical specimens having a diameter of 38 mm and height of 76 mm are prepared at 90% of the maximum dry unit weight with varying water content in the range of plastic limit. The experimental results revealed that water content has extreme effects in the reduction of unconfined compressive strength and this reduction is predominant while water content reaches near the liquid limit. It is also observed that the unconfined compressive strength of clay has a linear relationship to the water content. It is expected that the output of this research can be used to predict the reduction of unconfined compressive strength with the changes of water content.