Structural Geology and Rock Mechanics Quiz

Structural Geology and Rock Mechanics

Attitude of Beds

• Refers to the orientation of beds in space
• Defined by two measurements: strike and dip
• Strike: direction of the line produced by the intersection of an inclined rock layer with a horizontal plane
• Dip: angle at which the rock layer inclines from the horizontal, perpendicular to the strike

Outcrops

• Visible exposure of bedrock or ancient superficial deposits on the earth's surface
• Provide opportunities for geologists to directly observe and sample the bedrock in site for geologic analysis and creating geologic maps
• Extremely important for understanding the geologic time scale of earth history

Geological Maps

• Special-purpose map made to show various geological features
• Essential for understanding the geological history, tectonic processes, and natural resources of a given area
• Created by making careful field observations at numerous outcrops throughout the mapping area
• Rock units or geologic strata are shown by color or symbols

Engineering Geology

• Study of structures
• Provides essential information about the geological features and the potential hazards that may impact the construction project
• Used to determine the type of foundation suitable for the specific site conditions, considering the soil and rock properties and the potential for ground movement
• Used to determine the best ground improvement techniques to improve the strength, stiffness, and stability of the soil or rock

Rock Properties

Hardness

• Ability of a material to resist scratching, abrasion, penetration, or wear
• Ability of a material to resist plastic deformation

Elasticity

• Ability of a material to regain its original shape and size after the removal of external load
• Property of matter that causes it to resist deformation in volume or shape

Plasticity

• Ability of a material to withstand permanent deformation without failure

Dynamic Properties of Rocks

Wave Propagation

• P-waves (compressional or primary waves), S-waves (shear or secondary waves), surface waves (Love and Rayleigh waves)
• Used in seismology to study the interior of the Earth

Velocity

• Influenced by density, shear modulus, bulk modulus, pore pressure, and lithostatic pressure
• Velocity decreases with increasing density and pore pressure, but increases with shear modulus, bulk modulus, and lithostatic pressure

Igneous Massive Rocks

• Widely spaced joints help in breaking open the rock mass in excavations
• Understanding geological structures such as folds, faults, and joints ensures the stability and safety of structures

Rock Mechanics

• Theoretical and applied science of the mechanical behavior of rocks and rock masses
• Branch of mechanics concerned with the response of rock and rock masses to the force fields of their physical environment

Sub-Categories of Rock Mechanics

Engineering Rock Mechanics

• Applied in human activities including civil engineering, engineering geology, mining, petroleum, and environmental engineering
• Involves the application of the principles of engineering mechanics to the design of structures built in or on rock
• Structures include objects such as a drilling well, a mine shaft, a tunnel, a reservoir dam, a repository component, or a building

Geological Rock Mechanics

• Deals with the rock's response caused by natural geological processes such as faults, folds, or fractures
• If our aim is to lengthen or shorten a rock without actually breaking it, the greater the value of E, the larger the stress that is needed to achieve the deformation
• The static and dynamic moduli of the same rock may significantly differ from each other

Grouting

• Technique used in structural geology and rock mechanics
• Involves the injection of a grout (a fluid material) into cracks or voids in rocks or structures under pressure
• Purpose is to improve the physical and mechanical characteristics of the rock or structure

Key Points about Grouting

• Improves rock properties
• Seals and consolidates fractures and voids, reduces water flow, and controls seepage
• Widely used in various fields of rock and civil engineering, including tunneling, dam construction, mining, and foundation stabilization

Test your knowledge of Structural Geology and Rock Mechanics concepts, including attitude of beds, outcrops, and more!