Classification on jointed rock mass

Abstract

Rock mass classification is widely used throughout the underground mining industry in both coal and hard rock mines. It is used in all stages of the mining process, from site characterization to production operations. Rock mass characterization is an integral part of rock engineering practice. There is several classification systems used for design of structures on/in rock strata. It is interesting to note that these classification systems: RMi, RMR, Q and GSI, have their origin in civil engineering. Rock mass classification systems are used for various engineering design and stability analysis. These are based on empirical relations between rock mass parameters and engineering applications, such as tunnels, slopes, foundations, and excavatability. Rock mass classification systems have gained wide attention and are frequently used in rock engineering and design. However, all of these systems have limitations, but applied appropriately and with care as they are valuable tools. Different joint configurations will be introduced to achieve the most common modes of failure occurring in nature. A coefficient called Joint factor has been used to account for the weakness brought into the intact rock by jointing. Models have been being prepared using plaster of Paris and Lime-plaster of Paris mix specimens and different degrees of anisotropy have been induced by making joints in them varying from 0 to 90 degree. The specimen will be tested under direct shear, uniaxial compression to determine the various parameters. Rock mass classification system uses rock mass modulus for characterization of systems: RMR, Q, GSI and others. The rock mass classification includes some inputs obtained from intact rock and discontinuity properties, which have major influence on assessment of engineering behaviour of rock mass.