This document summarizes the key mechanical properties of rocks, including density, specific gravity, strength, strain, stress, porosity, and permeability. It defines each property, provides examples for common rock types, and notes that mechanics refers to how materials respond to applied loads. The conclusion restates that the document covered the mechanical characteristics of rocks according to these seven properties.

1. MECHANICAL
characters OF ROCK
seminar
on

2. contents
 Introduction
 Mechanical characters of rocks
 Density
 specific gravity
 strength
 strain
 stress
 porosity
 permeability
 Conclusion
 reference

3. INTRODUCTION
The material can be divided as
rocks,soil,&fluid. Rocks are the important
building materials and they provide foundation
to many engineering structure.
Mechanicsm refers to the response of
materials to applied load. This seminar deal
with mechanical characters of rocks

4. DENSITY
 Density is the term for how heavy an object is for its size.
 Density is usually expressed in units like grams per cubic
centimeter (g/cc or g/cm3
), kilograms per cubic meter,
pounds per cubic inch.
 Rocks considerably in high density, so the density of a rock
is often a good identification tool and useful for
distinguishing
 limestone (2.6 g/cm3
or less), quartzite (2.7 g/cm3
), and
granite (2.7-2.8 g/cm3
) are all common low-density rocks.
 The basalt one of the most common kinds of volcanic
rocks, its can be as high density as 3.0 g/cm3
.

5. SPECIFIC GRAVITY
. Specific gravity is the ratio of the mass
(weight) of a rock to the mass of the same
volume of water.
Water has a density of 1.0 g/cm3
, so the
numeric value of specific gravity for a rock
is the same as that for density. Because
specific gravity is a ratio, it has no unit.
Specific gravity is easier to measure than
density.

6. STRENGTH
The strength of a material defined as the lode under which
the material cracked and disintegrated.
The experimental definition of strength is determined by
increasing the lode observing at the point at which the first
crack appeared.
It is obvious that such criteria can’t applied to a piece of
rocks which is completely surrounded by other rock at the
depth in the earth’s crust.

7. STRAIN
Strain is the deformation caused by the strees,strain may
be dilation which is a change in volioum or distortion
which change in the form or both.
 The application of stress to a material causes it to deform.
The amount of deformation is called strain.
 axial strain:- deformation along the direction of loading.
 lateral strain:- the lateral extension perpendicular to the
direction of loading.
Poisson's ratio = (lateral strain)/(axial strain).

10. STRESS
Stress is force per unit area acting on a plane at any point
within a material. There are three types of stresses:
compressive stress:- equal forces that act towards a
point from opposite directions
tensile stress:- equal forces that pull away from each
other.
shear stress:- equal forces that operate in opposite
directions across the body.

12. POROSITY
Porosity is an index of the amount of the groundwater
that can be stored in the saturated formation.
Porosity Is the ratio between the total voids or pores of
particular rocks to the total volume of the same rocks.
It is usually expressed in percentage of the bulk volume
of the rocks.
There are two type of porosity
 Primary porosity (before the formation)
 Secondary porosity (after the formation)

13. Primary & secondary porosity

14. PERMEABILITY
Is the capacity of porous medium to transmit water or
liquid .ie,a relative easy to flow of a liquid under
unequal pressure.
It a factor how a rock will act as a source of water for a
well
A rock permeable when the rock has got many
connected pore space

15. conclusion
Mechanicsm refers to the response of materials to
applied loads.
specific gravity: the ratio between the mass and
that of equal volume of water.
 porosity n: measurement of the relative amount of
void space .
permeability: measurement of the rate at which
fluids will flow through a saturated materials.
Stress is force per unit area acting on a plane at any
point within a material.

16. Cont.……
The application of stress to a material causes it to
deform. The amount of deformation is called strain.
According to above mention features density,
specific gravity,strenght,strain,stress,porosity,and
permeability, are the mechanical characters of rocks.

17. REFERENCE
Books
 L.U de Sitter STRUCTURAL GEOLOGY (1956)McGraw- HILL
publishing company limited new york landon p18-p30
 Marland P Billings STRUCTURAL GEOLOGY(1984) third
edition prenticve hall of India privet limited new Delhi, p11-p34
 NW Gokhale THE THEORY OF STRUCTURAL GEOLOGY
(1996) CBS Publication & Distribution, p5-p19
Internet
 file:///F:/Mass,%20Weight,%
20Density%20or%20Specific%20Gravity%20of%20Bulk%20Materials.htm
 www.google.com