MECHANICAL PROPERTIES

Question 1

The tests are carried out on intact rock specimens in the
laboratory or on rock mass in the field to determine the strength
values.

Answer 1

MECHANICAL PROPERTIES

Question 2

There are two methods used in testing the strength:

Answer 2

1. Direct Methods for calculating the above strength values in the
   laboratory
2. Indirect Methods for determining the above strength value
   approximately in the laboratory or at the field site such as
   Compressive, Tensile and Shear Strength.

Question 3

is a measure of its
ability to resist uniaxial compressive loads without yielding
or fracture.

Answer 3

COMPRESSIVE STRENGTH

Question 4

is given by the ratio of load at failure or rupture to
crosssectional area of the specimen.

Answer 4

UNIAXIAL COMPRESSIVE STRENGHT

Question 5

Applying compressive load until failure
occurs in the core by a fracture in the
middle using high-capacity.
Compressive testing machinery verifies
the Uniaxial Compressive Strength of
rock material and deformation behavior
under loading.

Answer 5

UNIAXIAL
COMPRESSION TEST

Question 6

is the strength
exhibited by a rock specimen when it is
subjected to confining pressure in addition to
vertical pressure. Typically, at least 5
specimens are tested, each at a different
confining pressure, to determine the peak
strength. The Mohr’s envelope can also be
used to determine shear strength parameters
of rock materials using this test.

Answer 6

TRIAXIAL
COMPRESSION TEST

Question 7

Effects of Confining Pressure

Answer 7

• Peak strength increases.
• a transition from typically brittle to fully
  ductile behavior with the introduction of plastic
• mechanism of deformation

Question 8

Effects of Porewater Pressurev

Answer 8

• Transition from ductile to brittle behavior.

Question 9

used to determine the hardness of a rock sample’s
surface because it is simple to use and handle. The
sample should be in the form of a core or a block and
the test is nondestructive. The best part of the test is
that you can reuse the sample from the previous one.

Answer 9

SCHMIDT OR REBOUND
HAMMER TEST

Question 10

is an index test that classifies rocks based on their weight. Other
intact rock properties for which the test corresponds, such as
uniaxial compressive and tensile power, can be estimated using
the test. The strength ratio at point load in the directions with
the lowest and highest strength index values is defined by the
anisotropy index. The sample load and force gauges are part of
the test instrument, and the sample measurements (length
scale) are also determined..

Answer 10

POINT LOAD TEST

Question 11

is defined as the maximum tensile which a material is
capable of developing. In nature, rock mass is rarely
subjected to direct tension, but it is subjected to tensile
stresses. Rocks are weak in tension.

Answer 11

TENSILE STRENGTH

Question 12

The maximum resistance to deformation caused by shear stress
is known as shear strength. Surface frictional resistance along
the sliding plane, interlocking between individual rock grains,
and cohesion in the sliding surface of the rock all contribute to
the shear strength of a rock mass.

Answer 12

SHEAR STRENGTH

Question 13

DYNAMIC PROPERTIES OF ROCKS

Answer 13

1. STRESSWAVES
2. STRAIN
3. ELASTIC CONSTANT

Question 14

occur when the body is not in static equilibrium, and are essentially sound waves in solid materials

Answer 14

1. STRESSWAVES

Question 15

Also knows as deviatoric stress.

Answer 15

DIFFERENTIAL STRESS

Question 16

Rock beneath the Earth’s surface
experiences equal pressure
exerted on it from all directions
because of the weight of the
overlaying rock. It is the
hydrostatic stress (water pressure)
that a person feels pressing all
around the body when diving
down deep in water.

Answer 16

LITHOSTATIC STRESS

Question 17

deformation is the response to stress. Rock responds to
stress differently depending on the pressure, temperature and mineralogy of rock.

Answer 17

STRAIN

Question 18

is a temporary deformation that is fully recoverable when the stress is
removed. It’s like stretching a rubber band – it returns to its original shape.

Answer 18

Elastic Strain

Question 19

is a permanent deformation that occurs when the stress exceeds the
rock’s elastic limit. It’s like bending a metal bar – it stays bent after the force is
removed.

Answer 19

Ductile Strain

Question 20

is a type of rock deformation where rocks break or fracture
rather than bend, typically occurring at lower temperatures and pressures near the
Earth’s surface, resulting in features like faults and joints.

Answer 20

Brittle deformation

Question 21

They are used to characterize the elasticity of
materials, which is the ability of a material to return to its original shape after being
deformed by an external force.

Answer 21

3. ELASTIC CONSTANT

Question 22

pertains to young’s modulus.
Measures resistance of a solid to transmit load. Ratio of stress to strain.

Answer 22

MODULUS OF ELASTICITY

Question 23

pertains to the shear modulus. Denoted as g, sometimes s.
Ratio of shear stress to shear strain.

Answer 23

MODULUS OF RIGIDITY

Question 24

The resistance of a solid to change in volume when subjected
to compressional load. Ratio of the direct stress to the volumetric stress.

Answer 24

BULK MODULUS

Question 25

Defines the amount of expansion that can occur under dynamic loading. Determines the maximum amount of stress that can be tolerated before cracks are generated. Ratio of lateral strain and longitudinal strain.

Answer 25

POISSON'S RATIO (V)