A Study on Strength and Deformation Behaviour of Jointed Rock Mass

Rock, like soil, is sufficiently distinct from other engineering materials that the process of design in rock is very complex. In rock structures, the applied loads are often less significant than the forces deriving from redistribution of initial stresses. Hence, the determination of material strength requires as much judgement as measurement. A thorough review of literature on different aspects of jointed rock mass indicate that the behavior of jointed rock mass is influenced by many factors such as location of joints, joint frequency, joint orientation and joint strength. In the present study, an effort has been made to establish empirical relations to define the properties of jointed rock mass as a function of intact rock properties and joint factor. The effect of joints in the jointed rock is taken into account by the joint factor. The most important factors which govern the strength of rock mass are type of rocks, bedding planes, stress condition, presence of cracks and fissures, nature of joint surfaces and presence of minerals in bedding planes also play an important role in the strength and deformation behaviour of jointed rock mass. As the in situ determination of jointed rock mass is costly and time consuming, attempts are being made to predict the strength and deformation of rock mass through model test under controlled laboratory conditions.