State of ground stress its use and measurement in rock engineering with special reference to weak rocks

Determination of the initial state of stress in rock masses remains one of the most important and complex problems in rock mechanics. The difficulty arises primarily from geological complexity and the localized significance of individual measurements. As the knowledge of in-situ tensors is a basic input parameter like rock strength and modulus in the engineering design of underground cavities and other civil engineering structures, accurate forecasts of the state of stress require in-situ measurement. The stress measurement in weak rocks is altogether a different subject due to difficulties in the measurement and interpretation of the data. The paper discusses the definition, classification and usefulness of ground stress in brief. The achievements and shortcomings of various measurement techniques are analysed. Lastly the use of ground stress in rock engineering is reviewed with case histories specially taken from Weak Rocks.