Evaluation of Engineering Properties of Some Carbonate Rocks Trough Corrected Texture Coefficient

Abstract

Micro-fabric features are the main factor in determining the engineering properties of rocks. Engineering properties of sedimentary rocks are mainly influenced by grain shape, elongation, orientation, circularity, packing density, porosity, and matrix content, and all of these parameters are controlled by rock texture or micro-fabric. In this study, the relationships between engineering properties and rock texture have been investigated on carbonate rocks. Also, rock micro-fabric was quantified from the texture coefficient (TC) method which could be used to put a value on rock micro-fabrics with the textural parameters. This research presents a study on the TC of carbonate rocks and the main methods to determine and classify engineering properties. For this purpose, 28 carbonate rock samples which have middle to low strength were studied in different locations in Iran. TC values of samples are determined with microscopic laboratory studies carried out on rock thin sections using image analysis. Also, samples were tested in rock laboratory to determine unit weight (γd), porosity (P), water absorption (Wab), uniaxial compressive strength (UCS), point load index (Is50) and slake durability index. Regarding TC concept and previous studies, there is some shortage in TC and tried to solve them named corrected TC (CTC). The correlation coefficient (R), coefficients of determination (R2), standard error of the estimate and analysis of variance were used to evaluate the relationships between CTC and each engineering properties. Also, the correlation between TC, CTC and engineering properties of samples are highlighted. Results indicate that all engineering properties of carbonate rocks are mainly influenced by CTC. In addition, CTC had different effects on each engineering properties of samples. Overall, when CTC value is increased, the most of the engineering properties of samples are enhanced. Some engineering properties of samples such as UCS proved a close correlation to CTC, R2 = 0.92. Also, CTC classification is offered based on the engineering classification of samples. As a result, CTC can be used for evaluating and classifying the engineering properties of carbonate rocks in practical applications.