Effect of Water on Coal Strength

Abstract

Water content is one of the most important factors influencing the rock strength. The present study has been conducted to see how coal strength changes under dry and water saturated conditions. The study reveals that the strength of coal decreases with increasing moisture. For rock mechanics and rock engineering projects, it is strongly recommended that the dry uniaxial compressive strength is used for the purposes of strength classification, while for the actual engineering design it is essential to establish the wet strength and ideally the water sensitivity of the rock, in order to assess their potential change in strength and deformability. It has been observed that there is a significant reduction in strength when water is absorbed by coal. It has also been observed that the strength is higher in case the loading is done perpendicular to cleats as compared to when loading is done parallel to cleats. So, the orientation of cleats also plays a major role in the strength of coal. The specimen loaded parallel to cleats has a reduction in strength by 32.48% whereas the specimens loaded perpendicular to cleat has a reduction in strength by 29.29%.

Keywords: Coal Strength, Cleats, Loading Direction, Coal Saturation, Compressive Strength.