Geomorphic Processes and Rock Classification in Civil Engineering

What are the key processes driving changes in landforms?

Weathering, erosion, transportation, and deposition.

What is the difference between exogenetic and endogenetic processes?

Exogenetic processes occur above or on the Earth's surface, while endogenetic processes occur within the Earth.

What is weathering?

The process of breaking down rocks through mechanical, chemical, and biological means.

What are the three types of weathering?

Mechanical, chemical, and biological weathering.

What is mechanical weathering?

The physical breakdown of rocks into smaller fragments without changing their chemical composition.

What is chemical weathering?

The alteration of the chemical structure of rocks through reactions with water, air, and other substances.

What is biological weathering?

Weathering caused by the actions of living organisms, such as plants and animals.

What is erosion?

The process by which weathered material is removed from its source.

What are the main agents of erosion?

Water, wind, glacial ice, and waves.

What is mass movement?

The downslope movement of soil and rock due to gravity.

What factors contribute to mass movement?

Instability of slopes due to gravitational and water-related processes.

What is deposition?

The accumulation of sediment and rock material in a new location.

What is aggradation?

The raising of the ground surface due to the accumulation of sediment.

What is the role of climate in weathering rates?

High rainfall and temperature accelerate chemical weathering, while arid and cold conditions favor physical weathering.

How does topography affect weathering?

Steeper topography generally results in a higher rate of weathering.

What is denudation?

The process of exposing deposits through weathering and erosion.

What is liquefaction?

The softening and failure of soil deposits due to shaking, often during an earthquake.

What is a lahar?

A mudflow or debris flow consisting of a slurry of volcanic material.

What is the relationship between weathering and soil formation?

Weathering contributes to the breakdown of rocks, leading to the formation of soil.

What is the impact of vegetation on weathering?

Vegetation can enhance weathering through biological processes and by retaining moisture in the soil.

What is the role of time in weathering rates?

Longer exposure time generally leads to greater weathering effects.

What are the characteristics of sedimentary rocks?

Sedimentary rocks are formed from the accumulation and lithification of sediment.

What is lithification?

The process of turning sediment into solid rock through compaction and cementation.

What are the two main categories of rock discussed in geotechnical engineering?

Intact Rock and Rock Mass.

What characterizes Intact Rock?

It is continuous material with more consistent properties.

What is a Rock Mass?

A combined representation of rock and defects, where defects significantly influence engineering behavior.

What are the key descriptors used in rock classification?

Weathering, Colour, Fabric, and Rock Name.

How does weathering affect rock classification?

It can describe the overall rock mass and discontinuities within the rock mass.

What does the color of a rock indicate?

It provides indications of mineralogical composition, weathering, and moisture conditions.

What is meant by 'Fabric' in rock classification?

The arrangement of the minerals or particles in a rock, indicating the pattern.

What does 'Bedding' refer to in rock classification?

The thickness and orientation of layering in rock deposits.

What is compressive strength in the context of rock classification?

It characterizes the intact rock material's strength, assessed through field and lab-based approaches.

What are some methods to test rock strength?

Unconfined Compression Test, Point Load Test, and Rebound Hammer.

What are discontinuities in rock mass?

Defects within the rock mass that influence engineering behavior, including orientation, spacing, and roughness.

What does 'Orientation' describe in rock classification?

The orientation of planar features in 3D space, including strike and dip.

What is 'Strike' in geological terms?

The compass bearing along an imaginary line where dipping rock intersects a horizontal plane.

What is 'Dip' in geological terms?

The angle of maximum inclination of a feature from horizontal, indicating the direction of downslope.

How is 'Spacing' defined in rock classification?

The perpendicular distance between discontinuities.

What does 'Roughness' refer to in rock classification?

It influences the ability for surfaces to shear past each other, characterized as rough, smooth, or slickensided.

What is 'Aperture' in the context of rock discontinuities?

The distance between rock faces for a particular discontinuity.

What is 'Infill' in rock classification?

The type of material present within a discontinuity, such as soil or mineral deposition.