The failure, slaking, and self-sealing behavior of clay-bearing rocks

Abstract

Clay-bearing rocks with different thickness are commonly encountered in sedimentary rocks during many important engineering applications such as tunneling, underground and open-pit mining, and road cut or dam site constructions. Clay minerals are the main constituent of the mineralogical composition of such sedimentary rocks, and are the most important minerals that affect the strength and deformation behavior of these rocks. Due to the presence of clay minerals, the physico-mechanical features of these sensitive rocks are not constant and eventually change with variations in moisture content when subjected to natural environmental conditions. Many natural disasters and engineering projects–based problems such as landslide, slope instability, embankment failures, open-pit and underground excavation problems, and undercutting-related rockfalls generally have direct or indirect relationships with clay-bearing rocks due to their low durability and strength characteristics as well as high swelling tendency as a result of contact with water. Despite these natural disasters and engineering problems, due to their low characteristics of hydraulic conductivity and self-sealing behavior, the thermo-hydro-mechanical properties of clay-bearing rocks (e.g., Opalinus Clay and Boom Clay) have also been investigated up to now for the purpose of being used as host rocks for high-level radioactive waste. Particularly in the last two decades, the source of energy found trapped within shale formations has begun to be important in the popularity of these rocks. The reductions of conventional fossil fuels and worldwide high energy demands as well as occasional disruptions in energy supply have led scientists to do more investigation to achieve alternative energy sources from clay-bearing rocks. Considering low durability and strength dependent clay-bearing rocks–based engineering problems and the importance of these rocks for extraction shale gas and storage nuclear waste, the physico-mechanical and self-sealing characteristics of these rocks are comprehensively discussed and presented in this study.