Investigation on Various Relations Between Uniaxial Compressive Strength, Elasticity and Deformation Modulus of Asmari Formation in Iran

Abstract

Deformation modulus represents rock mechanical behavior before failure and is deployed as the most important parameter in understanding the deformation behavior of the rock mass. Two large concrete dams, namely, Karun IV and Khersan III located in Asmari Formation in the south of Iran, have been considered as case studies. In the present research, 30 data sets of uniaxial compressive strength (UCS), elasticity (E) and deformation modulus were utilized. The relations between the first to fifth loading cycles in plate loading test with E were studied. The results indicate that the correlation coefficient (R2) and the F values from analysis of variance are improved by increasing loading cycles. In other words, increasing the loading cycles leads to a decrease of the effect of discontinuities in relations between E and the deformation modulus. In this paper, the relation between UCS and E with Asmari deformation modulus obtained from the fifth cycle of plate load tests was used. Then, by employing artificial neural network, two equations for predicting deformation modulus of Asmari Formation are proposed. The results show that the predicted values of statistical and neural network methods have the highest accuracy by power relations and have a generally acceptable agreement with the in situ measurements. Also, the comparison between equations confirms that the modulus ratio as an input parameter has more effect on deformation modulus than E. Therefore, using the equations that utilize the modulus ratio is recommended for further practical use.