Common Terms applied to Rock Mechanics in Geotechnical Engineering

written by: Om Thoke • edited by: Lamar Stonecypher • updated: 2/16/2011

Rock mechanics is a field of engineering that involves interaction between geology, mathematics, physics, petroleum, mining, and civil engineering. There's a lack of standardization in rock mechanics terminology, so this beginner's guide is intended to help you get started with rock mechanics.

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What is Rock Mechanics?

The terminology of rock mechanics is related to the response of rocks as well as rock masses toward the force fields of their respective physical environment. In other words, it is the theoretical as well as applied science of the mechanical characteristics of rock masses.

Rock mechanics is a division of the broader topic, geomechanics, which is classified under geotechnical engineering; this subject deals with the mechanical reactions of all geological elements like soil, rock, etc.

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Overview

Presently, there is no complete correlation between the theoretical assumptions and experimental results. Hence, the principles depend on aspects like lab results, prototype behavior, and in-place measurements.

Out of these, in-place measurement is more emphasized since the properties of rock vary for different sites even if the geologic surroundings are similar.

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Basics of Rock Mechanics

To understand the basics of rock mechanics, it is important to know the engineering uses of rocks (they can be used as a building material as well as a foundation), rock measurements, rock properties, and its definition in engineering terms.

The physical features of the rock mass are a basic geological property that is very significant to engineers.

Difference between Rock and Stone

Though rock and stone mean the same in general terms, there's a distinctive difference between the two in engineering terms. Rock signifies a mass of material in the bedrock that is not disturbed or moved, while stone is a piece of material that has been moved from its bedrock position.

Rock mechanics terminology is not at all standardized as many interdisciplinary aspects need to be considered. However, given below are some of the definitions and terms that will be useful.

Ecological Features: They are the human influences and natural factors that need to be considered in engineering issues of rock mechanics.

The human influences are derived from mechanical, chemical, electrical, or thermal energy applications in the destruction of construction processes. The major environmental factors are hydrology, ambient stress, and geology.

Rock mechanics as applied in Mining, as well as other Civil Engineering Practices

In civil engineering, rock mechanics involves the application of principles of engineering mechanics for designing rock structures by means of drilling, reservoir production, mining shafts, open pit mines, gas/oil wells, underground excavations, waste repositories etc.

It even involves design of reinforcement systems including but not limited to rock bolting patterns.

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More Terminologies in Rock Mechanics

Ambient Stress: It is nothing but the numerical value of stress in the surrounding before any kind of disturbance caused by humans. Rock system is a term that comprises the entire environment to influence the characteristics of the specific part of earth’s crust. Usually, all the natural eco factors are included in it.

Rock Element: It is a term used to define the coherent rock piece, which is the basic element of a rock system. It features mechanical, petrographic, and physical properties that can be measured or explained by lab tests on such elements.

Rock Failure: It is a term used to signify that a rock system can no longer carry out the planned engineering functions. Such failures are indicated by fractures, reduction of strength, and distortion of shapes.

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And That's Not All!

Rock mechanics is a very interesting subject in the field of engineering and a significant part of geology. This is not all about the subject, but rather just the beginning!

Soil mechanics is also closely related to rock mechanics. We'll be covering several related topics individually in near future, but first off, It is very important to understand the fundamental principles that are used in the analysis of rock mechanics, in order to become acquainted with the field, let alone the prospects of becoming an expert (as there's a lot more that you'll have to learn and understand).