Prediction of uniaxial compressive strength of sandstones of Kashaf rud and Shurijeh Formation using petrographic and porosity characteristics

This study was evaluated relationships between uniaxial compressive strength with porosity and characteristics of petrography contains type of cement and quantities of quartz, feldspar and rock fragment on 22 samples of sandstone which collected from formation of Kope Dogh zone. Use of correlation relations among uniaxial compressive strength with petrographic properties can be used in the estimation of compressive strength at a lower cost and less time. For this purpose used Pearson correlation coefficient and univariate and multivariate statistical regression. The results show that the method of petrography introduced to calculate uniaxial compressive strength is a method with low error estimation to find the strength of sandstones studied. These results showed that in sandstones, unlike other rocks the role of the type of cement (silica or calcium) on the strength of these types of rocks is more than the role of the type of constituent minerals and porosity. According to the results a relationship with acceptable accuracy is proposed to predict the uniaxial compressive strength of sandstones based on the percentage and type of cement.