The effect of clay content and slake durability on the compressive strength of weak rocks

In order to investigate the effect of clay content and slake durability on the compressive strength of weak rocks, eight different weak rock samples from the Sultanate of Oman were subjected to rigorous experimental analyses. In order to gel a reasonable spread of the geological depositional environments, samples were taken from different lithological units. The plasticity and the XRD analyses were performed to quantify the clay content. For this purpose, clay fraction was carefully separated from the rest fo the sample. The slake durability index is taken as a measure to represent the insitu characteristics of weak rocks. The compressive strength was determined by number of direct and indirect techniques. Result of this study shows a direct relationship between the compressive strength and clay content of the weak rocks. The scatter present in the data is mainly attributed to limited number of samples and the inability of the testing procedures to determine the compressive strength of weak rocks to a higher degree of accuracy.