14.330 Soil Mechanics - Geology
NATURAL SOIL DEPOSITS
Soils are produced by weathering of rock.
Weathering is the physical or chemical breakdown of
rock.
Physical Processes:
- Unloading
- Frost Action
- Organism Growth
- Crystal Growth
- Abrasion
Revised 1/2012
Chemical Processes:
- Oxidation
- Hydration
- Hydrolysis
- Carbonation
- Solution
after FM 5-410 Military Soils Engineering
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14.330 Soil Mechanics - Geology
ROCK-SOIL RELATIONSHIPS
•  Igneous Rocks
•  Granite > silty sands
•  Basalts > clayey soils
•  Sedimentary rocks
•  Shales > clays and silts
•  Sandstones > sandy soil
•  Limestone > coarse or fine grained soils
•  Metamorphic rocks
•  Gneiss > silty sands
•  Slate > clayey soils
•  Marble > fine grained soils
•  Quartzite > coarse grained soils
Revised 1/2012
from Dr. Larry Muszynski
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14.330 Soil Mechanics - Geology
SOIL FORMATION METHODS
Two Main Groups:
Residual Soils
Rock material weathered in place
via mechanical and chemical
processes (chemical usually
dominant factor).
As a result of this process, and
because the rock material may
have an assorted mineral structure,
the upper layers of soils are usually
fine-grained and relatively
impervious to water.
Transported Soils
Soils transported from place of
origin via three main processes:
1. Water
2. Glacial
3. Air
Most soils are transported soils.
Example: Cape Cod.
Example: Piedmont (Eastern US).
Revised 1/2012
after FM 5-410 Military Soils Engineering
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14.330 Soil Mechanics - Geology
RESIDUAL SOILS
TYPICAL WEATHERING PROFILES
(a)  Mudstone, Shale,
and Slate
(b) Gneiss and Schist
(c) Granite to Gabbro;
from Sowers, G.F. 1988. Foundation problems in residual soils. Proceedings, Engineering Problems of Regional Soils: 154- 171. Beijing,
China and Sowers, G.F. (1994). "Residual soil settlement related to the weathering profile." Vertical and Horizontal Deformations of
Foundations and Embankments, ASCE GSP 40, 1689-1702.
Revised 1/2012
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14.330 Soil Mechanics - Geology
RESIDUAL SOILS
TYPICAL WEATHERING PROFILES
(a) Metamorphic Rocks
ZONE
Colluvium of other
transported soils;
“pebble marker”
common here
(b) Intrusive Igneous Rocks
ZONE
Colluvium etc.
IA
IA
A horizon
I
Residual
Soil
IB
IB
B horizon
IC
IC
C horizon
(Saprolite)
IIA
IIA
Transition
from
Saprolite to
Weathered
Rock
II
Weathered
Rock
IIB
IIB
Partly
Weathered
Rock
III
Unweathered
Rock
Revised 1/2012
III
Figure3-2.
3-2. Typical
weathering
profile for metamorphic
igneous rocks
(DeerePatton,
and Patton, 1971).
Figure
from
NHI-06-088
(afterandDeere
and
1971).
FHWA NHI-06-088
Soils and Foundations – Volume I
3-8
3 – Subsurface Explorations
December 2006
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14.330 Soil Mechanics - Geology
RESIDUAL SOILS – PIEDMONT PROVINCE
Covers ~1/3 of
SC and NC.
Eastern Border of
Province called
Fall Line
“Georgia Red
Clay” – Residual
Soil
Figure from Finke, K.A., Mayne, P.W. & Klopp, R.A. (2001). Piezocone penetration testing in
Atlantic Piedmont residuum. Journal of Geotechnical & Geoenvironmental Engineering 127 (1).
Revised 1/2012
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14.330 Soil Mechanics - Geology
TRANSPORTED SOIL DEFINITIONS
Glacial Soils: formed by transportation and
deposition of glaciers.
Alluvial Soils: transported by running water and
deposited along streams.
Lacustrine Soils: formed by deposition in quiet lakes.
Marine Soils: formed by deposition in seas/oceans.
Aeolian Soils: transported and deposited by the wind.
Colluvial Soils: formed by movement of soil from its
original place by gravity (e.g. landslides).
from Das, B.M. (1998). Principles of Geotechnical Engineering, 4th edition, PWS Publishing Company.
Revised 1/2012
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14.330 Soil Mechanics - Geology
TRANSPORTED SOILS
Meander and
Erosion along
Rivers
Meander
Development &
Cutoff
Revised 1/2012
from FM 5-410 Military Soils Engineering
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14.330 Soil Mechanics - Geology
TRANSPORTED SOILS
Oxbow Lake Deposits
Revised 1/2012
from FM 5-410 Military Soils Engineering
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Address Northampton, MA
14.330 Soil Mechanics - Geology
TRANSPORTED
SOILS
Oxbow Lake
Example
Northampton, MA
Revised 1/2012
Map courtesy of Google.com
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14.330 Soil Mechanics - Geology
TRANSPORTED SOILS
Major Floodplain Features
Revised 1/2012
from FM 5-410 Military Soils Engineering
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14.330 Soil Mechanics - Geology
NEW ENGLAND GEOLOGY
Revised 1/2012
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14.330 Soil Mechanics - Geology
NEW ENGLAND GEOLOGY
Revised 1/2012
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14.330 Soil Mechanics - Geology
NEW ENGLAND GEOLOGY
Revised 1/2012
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14.330 Soil Mechanics - Geology
NEW ENGLAND GEOLOGY
Revised 1/2012
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14.330 Soil Mechanics - Geology
NEW
ENGLAND
GEOLOGY
Surficial Geologic Map of
the Ashby-Lowell-SterlingBillerica
11-Quadrangle Area
(Stone and Stone, 2007)
Revised 1/2012
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14.330 Soil Mechanics - Geology
Revised 1/2012
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