Abstract

Igneous rock is one of the three main rock types, other being sedimentary rocks and metamorphic rocks. Igneous\nand metamorphic rocks make up 90–95% of the top 16 km of the Earth\'s crust by volume. The engineering properties of these\nrock types essentially depend on physical properties of minerals and thus show varied characteristics. Hence in broader sense,\nthese rocks can also be differentiated on the basis of their engineering characters. It is widely accepted that strength,\ndeformation and permeability are the key engineering parameters that define the suitability of any rock type in general. Many\nresearchers so far have tried to derive relationships between different physical properties and engineering properties of\nIgneous rocks. In Civil engineering precise knowledge of Unconfined Compressive Strength (UCS) of different rocks in\nvarious regions is considered to be of crucial importance. Unconfined compressive strength (uniaxial compressive strength) is\nthe strength of rock or soil sample when crushed in one direction (uniaxial) without lateral restrain. It was found that\nunconfined compressive strength (UCS) of intact rock is a key parameter required for the design of various geo-mechanical\nproblems ranging from wellbore instabilities during drilling, evaluation of sand production potential and quantitatively\nconstraining stress magnitudes using observations of wellbore failure. In this review paper thus the emphasis is placed on\ntrends of differentiation of Igneous rocks based on UCS tests and analysis. A brief overview of classification of Igneous\nrocks and a summary on different methodologies for determining the UCS of Igneous rocks has been discussed in this paper.