The Effect of Poisson's Ratio on Rock Properties

Abstract

American Institute of Mining, Metallurgical, and Petroleum Engineers, Inc. Abstract This paper presents various relationships between Poisson's ratio and other rock properties such as overburden pressure, bulk properties such as overburden pressure, bulk compressibility, Young's modulus, modulus of rigidity, compressive and tensile strength, porosity, density, wave velocities, modulus of porosity, density, wave velocities, modulus of resilience, modulus of rupture, fractures, drillability, and hardness. Thus, it points out the importance of Poisson's ratio in the understanding of some of the questions in rock mechanics. Introduction Though the change in Poisson's ratio for various types of rocks is small in general, sometimes this change can be significant. Assumption of a constant value of Poisson's ratio in some cases may result in serious errors. Unfortunately, the importance of Poisson's ratio in the understanding of other rock properties is not fully realized and very little work, both theoretical and practical, has been done on this subject. This paper presents various relationships between Poisson's ratio and other rock properties such as overburden pressure, bulk properties such as overburden pressure, bulk compressibility, Young's modulus, modulus of rigidity, compressive and tensile strength, porosity, density, wave velocities, modulus of porosity, density, wave velocities, modulus of resilience, modulus of rupture, fractures, drillability, and hardness. Thus, it points out the importance of Poisson's ratio in the understanding of some of the questions in rock mechanics. POISSON'S RATIO POISSON'S RATIOWhen a force is applied to a body, at right angles to the force, a certain amount of lateral (transverse) expansion or contraction takes place. This phenomenon is shown in Fig. 1. In place. This phenomenon is shown in Fig. 1. In other words, it can be said that, if a solid body is subjected to an axial tension, it contracts laterally; on the other hand, if it is compressed, the material expands sidewise. So the definition of Poisson's ratio can be stated as the ratio of transverse strain to axial strain induced by unconfined axial deformation. Poisson's ratio can be expressed as(1) where the strains are caused by uniaxial strain only. Generally, values of Poisson's ratio vary between 0.25 and 0.35.