Index properties of rock

3. properties of the rock.
• According to the classification system
recommended by the
International Society of Rock Mechanics (ISRM
1978c),
rock may range from extremely weak to extremely
strong
depending on the unconfined compressive
strength (or
Point Load Strength Index) or approximate field
identification.

4. Index Properties
•Specific Gravity of Solids
•permeability
•Porosity
•density
strength
1) Compressive Strength
2)Tensile Strength
•Elastic Modulus
ultrasonic velocity
etc

5. Density
Density is defined as the mass per volume of
a substance.
Rock density is very sensitive to the minerals
that compose a particular rock type.
Sedimentary rocks (and granite), which are
rich in quartz and feldspar, tend to be less
dense than volcanic rocks. And if you know
your igneous petrology, you will see that the
more mafic a rock is, the greater its density.

6. • Density
• rock type density (grams per cubic cm)
quartzite2.65
salt2.10–2.20
schist2.73–3.19
shale2.06–2.67

7. One of the heavier minerals, gold has
a density of 19.32.

8. Porosity and Permeability
Porosity and permeability are related properties of
any rock or loose sediment. Most oil and gas has
been produced from sandstones. These rocks often
have high porosity, and are usually “high perm” too.
Porosity consists of the tiny spaces in the rock
that hold the oil or gas.
Permeability is a characteristic that allows the oil and
gas to flow through the rock.

9. permeability
Permeability is the interconnected pore space.
The permeability of a rock is a measure of the
resistance to the flow of a fluid through a
rock. If it takes a lot of pressure to squeeze
fluid through a rock, that rock has “low
permeability” or “low perm.” If fluid passes
through the rock easily, it has “high
permeability,” or “high perm.”

11. Porosity (n)
ratio of void or pore volume (Vv)
to the total volume,(V) of the rock. It is dimensionless and
varies significantly for different rock types or even for the
same rock
type due to different factors such as grain size distribution,
grain
shape , depth and pressure
n = Vv/V

12. Specific gravity
• It is the ratio between volume of rock mass
and volume of water at 4centi grade .greater
the specific gravity lower will be the water
Obsorbtion denser the material

13. Average Specific Gravity of Various Rock Types
Andesite2.5 - 2.82.11 - 2.36
Basalt/Traprock2.8 - 3.02.36 - 2.53
Coal - Anthracite1.31.08
Coal - Bituminous1.1 - 1.40.92 - 1.18
Copper Ore21.89
Diabase2.6 - 3.02.19 - 2.53
Diorite2.8 - 3.02.36 - 2.53
Dolomite2.8 - 2.92.36 - 2.44
Earth (dry)1.6 - 1.81.35 - 1.52
Earth (wet)21.6875
Gneiss2.6 - 2.92.19 - 2.44
Granite2.6 - 2.72.19 - 2.28
Gypsum2.3 - 2.81.94 - 2.36
Iron Ore4.5 - 5.33.79 - 4.47

14. Sonic velocity
the velocity with which stress waves are
transmitted Sonic velocity evaluate the degree of
fissuring( planar cracks in igneous and
metamorphic rock)
sonic velocity as an index to degree of fissuring
First calculate the longitudinal wave velocity that
the specimen would have , if it lakcked pores or
fissures.

15. Strength
Strength determination of rock usually
require careful test setup and
specimen preparation and the result
are highly sensitive to the method and
style of loading strength index is now
available using the point load test
b/w the point loads Where P is the load of rupture
& D is the distance

20. THANK YOU