C4: ROCK MECHANICS AND THE PROPERTIES OF ROCKS (PHYSICAL, MECHANICAL, AND DYNAMIC PROPERTIES).

Question 1

is a discipline that uses the principles of mechanics to describe the behaviour of rocks under various physical forces.

Answer 1

ROCK MECHANICS

Question 2

In 1963, the ___________ was founded and the term adopted the following definition

Answer 2

Rock Mechanics Committee of the American
National Academy of Science

Question 3

the theoretical and applied science of
the mechanical behaviour of rock. It is the branch of mechanics concerned with the response of rock to the force fields of its physical environment.

Answer 3

Rock mechanics

Question 4

TWO MAJOR BRANCHES OF ROCK MECHANICS:

Answer 4

1. STRUCTURAL ROCK
   MECHANICS
2. COMMINUTION

Question 5

Typically continuous,
homogeneous, isotropic, and linearlyelastic (CHILE). Their
properties are well-known and controllable during
production.

Answer 5

Construction Materials

Question 6

Are discontinuous, inhomogeneous, anisotropic, and non-linearly elastic (DIANE). The properties of rocks are often variable and difficult to control, making their behavior less predictable.

Answer 6

Rocks

Question 7

are fractures or breaks in rocks that
affect their mechanical behaviour

Answer 7

Discontinuities

Question 8

These include large, smooth
fractures that are often weathered or infilled, such as faults,joints, bedding, and fractures

Answer 8

Normal Discontinuities

Question 9

These are smaller, rough, and often fresh fractures with no specific pattern, typically created by human activities.

Answer 9

Artificial Discontinuities

Question 10

This refers to the
variation in rock properties at different locations, often
due to mineral composition or the presence of discontinuities.

Answer 10

Inhomogeneity of Rock Materials:

Question 11

This is primarily caused by
the existence of discontinuities in the rock mass, which
significantly affect its mechanical behavior.

Answer 11

Inhomogeneity of Rock Masses

Question 12

is defined as variation of properties with respect
to the directions concerned in design and analysis of rock
structures.

Answer 12

Anisotropy

Question 13

is the force per unit area applied to a rock. It
can be classified into:

Answer 13

Stress

Question 14

Stress that acts perpendicular to a surface.

Answer 14

Normal Stress

Question 15

Stress that acts parallel to a surface.

Answer 15

Shear Stress

Question 16

• may be known as Index Properties
• it describes the rock material and helps in classifying them

Answer 16

Physical Properties

Question 17

The composition,structure, and texture of rock materials directly control their strength. While there are over 2,000 known minerals, only about nine play a significant role in rock formation.

Answer 17

Mineralogic Composition, Structure, and Texture

Question 18

is the ratio of the density of the rock to the density of water. It helps determine whether the rock will float or sink.

Answer 18

Specific Gravity(G)

Question 19

also known as specific weight, relates the rock’s size, mass, density, and force.

Answer 19

Unit Weight (Y)

Question 20

refers to how compact the rock is, and It is related to its mineral composition.

Answer 20

Density

Question 21

Is the ratio of the volume of voids to the volume of solids, and is related to porosity.

Answer 21

Void Ratio

Question 22

is the proportion of the volume that is not solid, affecting water storage and permeability.

Answer 22

Porosity

Question 23

influences physical properties such as weight and density.

Answer 23

Moisture Content

Question 24

indicates how much moisture is present in the rock relative to its total void capacity.

Answer 24

Degree of Saturation

Question 25

Describes the rock's ability to transmit fluids. Highly porous rocks with well connected voids have high permeability.

Answer 25

Permeability

Question 26

majority of rocks are dielectric, and measurements of dielectric constants are used to interpret data.

Answer 26

Electrical Properties

Question 27

The increase in temperature also makes rock weaker due to the formation of cracks in the rock mass

Answer 27

Thermal Properties:

Question 28

occurs when rocks absorb water and Increase in volume.

Answer 28

Swelling

Question 29

refers to the condition where the properties of a rock mass vary depending on the direction.

Answer 29

Anisotropy

Question 30

refers to how resistant rocks are to weathering and other forms of degradation overtime.

Answer 30

Durability

Question 31

describe a rock' s strength and its ability to resist Deformation under load.

Answer 31

Mechanical properties

Question 32

The ability of a rock to withstand axial loads without failure.

Answer 32

Compressive Strength:

Question 33

is determined by dividing The load at failure by the cross-sectional area Of the rock.

Answer 33

Uniaxial compressive Strength

Question 34

Tests like the uniaxial compression and triaxial compression tests directly measure compressive strength.

Answer 34

Direct Methods

Question 35

Techniques like the Schmidt Hammer Test and Point Load Test estimate compressive strength without damaging the rock sample

Answer 35

Indirect Methods

Question 36

The maximum tension a rock can withstand before failure. Rocks are generally weak in tension, but tensile strength is important for understanding failure

Answer 36

Tensile Strength

Question 37

Involve applying uniaxial tensile stress.

Answer 37

Direct Methods

Question 38

Techniques like the Brazilian Disc Test estimate tensile strength nondestructively.

Answer 38

Indirect Methods

Question 39

This refers to the maximum resistance to deformation caused by shear stresses. It is essential for analyzing rock slopes and foundations.

Answer 39

Shear Strength:

Question 40

Include laboratory tests to measure shear resistance along weakness Planes in the rock.

Answer 40

Shear Strength Tests

Question 41

are generated when stress is applied to a rock, causing deformation that propagates as sound waves through the material. They are essential for understanding seismic activities.

Answer 41

Stress waves

Question 42

Pressure experienced by rocks due to the weight of overlying materials.

Answer 42

Lithostatic Stress

Question 43

Unequal stress experienced by rocks, often caused by tectonic forces.

Answer 43

Differential Stress

Question 44

The deformation or change in shape that occurs in response to applied stress.

Answer 44

Strain

Question 45

The rock returns to its Original shape after the stress is removed.

Answer 45

Elastic Deformation

Question 46

Occurs under high temperature and pressure, causing the rock to flow rather than fracture.

Answer 46

Ductile Deformation

Question 47

Characterized by rock fracturing when stress exceeds its yield strength.

Answer 47

Brittle Deformation

Question 48

These constants describe the rock's ability to return to its original shape after deformation

Answer 48

Elastic Constants

Question 49

4 elastic constants

Answer 49

1. modulus of elasticity (young's modulus) 2. shear modulus 3. bulk modulus 4. poisson's ratio

Question 50

Measures resistance to compression.

Answer 50

Modulus of Elasticity (Young’s Modulus

Question 51

Measures resistance to shear deformation.

Answer 51

Shear Modulus

Question 52

Measures resistance to volume change under pressure.

Answer 52

Bulk Modulus

Question 53

Describes the relationship between lateral strain and longitudinal strain underloading.

Answer 53

Poisson's Ratio