LE 1 CONCEPTS (M1 - M3) Flashcards
a dynamic natural body on the surface of the earth in which plants grow, composed of mineral and organic materials and living forms. (Brady)
Soil in Agriculture
it is a loose surface of the earth as distinguished from solid bedrock
Soil in Geology
the uncemented aggregate of mineral grains and decayed organic matter (solid particles) with liquid and gas in the empty spaces between the solid particles.(Das)
Soil in Engineering
naturally occurring solid aggregate of one or more minerals or mineraloids.
Rock in Geology
the aggregation of minerals into a hard mass
Rock in Engineering
the subdiscipline of civil engineering that involves natural materials found close to the surface of the earth. It includes the application of the principles of soil mechanics and rock mechanics to the design of foundations, retaining structures, and earth structures.
Geotechnical engineering
Father of Soil Mechanics
Karl Terzaghi
Branches of Geotechnical Engineering
- Soil Mechanics
- Rock Mechanics
- Geoenvironmental Engineering
- Foundation Engineering
- Geotechnical Earthquake Engineering
- Geologic Engineering
Exploration Program
- Collection of Preliminary Information
- Reconnaissance of the Area
- Preliminary Site Investigation
- Detailed Investigation
Assembly of all available information on dimensions, column spacing, type and use of the structure, basement requirements, and any special architectural considerations of the proposed building
Collection of Preliminary Information
- The general topography of the site, including drainage paths, creep of slopes, deep/wide cracks
- Soil stratification from deep cuts from nearby construction
- Vegetation type
- High-water marks on nearby buildings
- Ground water levels from nearby wells
- The types of constructions nearby.
Reconnaissance of the Area
- Soil pits
- Exposes the shallow-level soil profile
- does not guarantee reliable or even consistent data
- soils have very poor homogeneity
Preliminary Site Investigation
- Where the preliminary site investigation has established the feasibility of the project, a more detailed exploration program is undertaken
- Laboratory testing
- To classify the soils.
- To determine soil strength, failure stresses and strains, stress–strain
response, permeability, compactibility, and settlement parameters.
Detailed Investigation
Depth of boring for Compressible Soils (Clays)
at least between 1 and 3 times the width of the proposed foundation below the depth of embedment or until the stress increment due to the heaviest foundation load is less than 10%, whichever is greater
Depth of boring for Coarse-grained Soils
5 m to 6 m to prove that the thickness of the stratum is adequate
Minimum Depth of Boreholes
6 m unless bedrock or very dense material is encountered
Minimum no. of boreholes for buildings with area < 100 m^2
2 boreholes
Minimum no. of boreholes for subdivisions with area < 4000 m^2
2 boreholes
Common Methods of Drilling
*Wash Boring
*Rotary Drilling
Water with high pressure pumped through hollow boring rods is released from narrow holes in a chisel attach to the lower end of the rods.
Wash Boring
Type of Soil unsuitable for wash boring
coarse gravel strata
Primarily intended for investigation in rock, but also used in soils.
Rotary Drilling
Fluid used in rotary drilling
Bentonite slurry
Type of Soil unsuitable for rotary boring
soil containing a high percentage
of gravel/cobbles
Type of Soil Samples
- Disturbed
- Undisturbed
*In situ structure not retained
*Water content, classification, compaction
Disturbed
*Less disturbed
*Shear strength, consolidation, permeability
Undisturbed
generally a three phase system. It consists of solid particles, liquid and gas.
Soil mass
