Effect of Structure of Clay Mineral on the Physical and Mechanical Properties of Rock Materials

Abstract

It is generally known that physical and mechanical properties of rock materials significantly change by clay mineral content. Therefore, it is considered that clay mineral content or type is one of the factors that greatly affect the rock strength. In order to clarify that effect of only clay mineral content, a series of experiments has been carried out on artificial rock by the use of gypsum specimen mixed with clay minerals. The value of P-wave velocity, uniaxial compressive strength and degree of strength reduction differ with the clay mineral content and type. Comparative tests revealed that the difference of clay mineral content or type in the clay mineral-bearing rock material specimens influences the physical and mechanical properties of rock materials. Furthermore, the results suggested that uniaxial compressive strength of clay mineral-bearing rock materials under dry condition can be evaluated on the basis of interlayer bonding force (i.e. chemical bonds type) in the clay minerals. Our results can be useful and contribution as basis data when evaluating physical and mechanical properties of clay mineral-bearing rock materials.