Lesson 1: Soil Formation Flashcards
(67 cards)
it is defined as the uncemented aggregate of mineral grains and decayed organic matter (solid particles) with liquid and gas in the empty spaces between the solid particles.
Soil
it is used as a construction material in various civil engineering projects and it supports structural
foundations.
Soil
Is a branch of science that deals with the study of the
physical properties of soil and the behavior of soil
masses subjected to various types of forces.
Soil Mechanics
Subdiscipline of civil engineering that involves natural
materials found close to the surface of the earth.
Geotechnical Engineering
This includes the application of the principles of soil mechanics and rock mechanics to the design of
foundations, retaining structures, and earth materials.
Geotechnical Engineering
The Application of principles of soil mechanics to engineering problem:
a. Highway retaining wall
b. Building basement walls
c. Bridge abutments
d. Earth dam
e. Waterfront bulkhead
Examples of Geotechnical Systems:
- Dams
- Tunnels
- Excavations
- Slope stabilization
- Earth retaining structures
- Subgrade support
- Ground improvements
- Foundation for buildings
Examples of Geotechnical Failures:
- Leaning Tower of Pisa
- Failure of Transcona Grain Elevator
Soils are formed by ____________ of rocks.
weathering
the chemical elements that constitute rocks
Minerals
the aggregation of minerals into a hard mass
Rocks
average particle diameter of the soil at the 10th percentile or 10% of the particles are smaller that this diameter size.
Effective particle size (D10)
average particle diameter of the soil
Average particle diameter (D50)
numerical measure of uniformity
Uniformity of coefficient (Cu)
measure of the shape of the particle distribution curve (coefficient of gradation/ coefficient of concavity)
Coefficient of curvature (Cc)
measure of the shape of the particle distribution curve (coefficient of gradation/ coefficient of concavity)
Coefficient of curvature (Cc)
Process of which rocks are broken into pieces by physical force
Mechanical Weathering
Process of chemical decomposition of the original rock
Chemical Weathering
Rocks can be divided into three basic types:
- Igneous rock
- Sedimentary rock
- Metamorphic rock
Rocks that are formed by the solidification of molten magma ejected from deep within the earth’s mantle.
Igneous rock
Soils that are formed by the weathered products at their place of origin. These soils retain many of the elements that comprise the parent rock.
Residual Soil
The composition of these soils depends on the environment under which they were transported and is often different from the parent rock.
Transportation soil
The five major categories of Transported Soils:
a) Colluvial/ Gravity Transported - soils from
landslides or mudflows.
b) Lacustrine - formed by deposition in quiet lakes.
c) Alluvial - transported by running water &
deposited along streams.
d) Glacial - formed by transportation and
deposition from glaciers.
e) Aeolian - transported & deposited by wind.
f) Marine - formed by deposition in the seas.
The deposits of gravel, sand, silt, and clay formed by weathering may become compacted by overburden pressure and cemented by agents like iron oxide, calcite, dolomite, and quartz. Rocks formed this way is called:
Sedimentary Rocks