Estimation of the deformation modulus of rock mass is one of the most important design parameters in a rock engineering project. This paper presents the results of series of laboratory experiments and in-situ measurements of deformation modulus of intact rock and rock mass in Karun dam in Iran. The study aimed at obtaining a correlation between the field and lab deformation modulus in the studied region. Total number of 51 samples were collected and tested in the technical and soil mechanics laboratory according to ASTM and ISRM standard methods in order to estimate the elastic modulus of the rock. Also, in-situ deformation modulus of rock mass was measured using dilatometer tests. Correlation was developed between the field and lab deformation modulus which allows estimation of this parameter to be made in nearby regions. The detailed lab procedure and the results are presented in this paper.
Deformation modulus is one of the most important parameters used in order to estimate various rock mass properties in a rock engineering projects. Estimation of deformation modulus can be done through lab experiments or in-situ tests, the latter being more reliable (ASTM, 2000). However, it is well known that, field experiments are significantly more time consuming and costly than that of laboratory experiments. Therefore, estimation of in-situ properties from lab results is a common practice (Bieniawski, 1989). Different in-situ measurements of deformation modulus are used including dilatometer and plate or radial jacking methods. The use of each of these methods requires special considerations associated with the method application itself and site preparation (Bulat, 2004). On the other hand, the standard procedure for estimation of the modulus of deformation of rock mass has been proposed by the ISRM and ASTM D3148 (Gokceoglu, 2003 & Hoek, 2006).