Estimating Rock Mass Long-Term Strength Using In-Situ Measurement And Testing Results

A method for estimating rock mass long-term strength (σLT) using the results of in situ measurement and test has been developed. It consists of estimation of rock mass strength (σcm) using Hoek-Brown criterion, determination of rock mass modulus of deformation (Em) through Goodman’s jack test, and construction of rock mass rheological model based on displacement monitoring data, taking into acount the stress changes due to stoping activities underneath the test and monitoring locations. The rheological model is used to determine the rock mass long-term modulus of deformation (ELT). It is proposed that the long-term strength of rock mass can be estimated by using the rock mass strength and deformation modulus, rock mass long term modulus, and a coefficient on the rock mass characteristics. Keywords: Rock mass; Hoek-Brown criterion; Long-term strength; Rheological model.