BEARING CAPACITY OF SHALLOW FOUNDATIONS ON JOINTED ROCK

Abstract

Rock is a very different engineering material and the process of designing a structure in a rock mass is a very complex problem. The distribution of stresses in the rock mass is equally important as the applied loads. Therefore measurement and judgment both are important while determining the material strength. The behavior of jointed rock mass depends upon many like joint frequency, location of joints, joint orientation, infill material, joint strength etc. The present study aims at studying the variation of bearing capacity of shallow foundation resting over a jointed rock mass through model study. As the process of determining in situ strength of a jointed rock mass is very expensive and difficult, many researchers have performed model studies to predict the strength behavior. The important factors on which strength of a rock mass depends are type of rock, bedding planes, condition of initial stress, presence of joints and cracks, nature of joint surface and the presence of infill material between the bedding planes.

Rocks are not found in intact state anywhere in the world, they essentially have faults and fissures in them which make it an anisotropic medium. These discontinuities like fissures, cracks, joint, bedding plane and faults make a rock weaker and more prone to deformations. In the case of important structures like a dam, leakage of water can take place due to this which can lead to loss of energy and erosion of the dam.