2. Faculty of Earth Sciences
King Abdul-Aziz University
Course Description (Theoretical)
Department: Engineering and Environmental Geology
Course Symbol: EEG
Course name:
Number: 341
Engineering Geology
Pre-requisite Courses: EEG 311, EEG 322
Course description: - Engineering geological consideration, description of soils and rock
masses. Classification of rock masses for engineering purposes. Engineering geological maps
and their applications. Requirement of conducting Engineering Geological studies and Writing
Reports, Rock and soil improvement such as grouting, drains and reinforcement of ground (2
days Field Trips)
Course objectives:
1. To outline the contribution of engineering geology to the civil and mining works
2. To explain the classical approach to solve an engineering geological problem
3. The extensive uses of engineering geology maps
4. The role and effect of engineering geology in the improvement of earth materials
General references for course: (Books/Journals…etc.)
1. Engineering Geology and Geotechnics by BELL, F. G., 1980.
2. Engineering Geology: Rock Engineering in Construction by GOODMAN, R.E.,
1993
3. Engineering Geology: An Environmental Approach by RAHN, P. H., 1986
4. Engineering Geology by ZARUBA, Q., and MENCL, V., 1976
Internet links:
Geology and Geological Engineering
Geotechnical and Geoenvironmental Software Directory
Geophex, Ltd.
GeoLine
SpringerLink: Bulletin of Engineering Geology and the Engineering Geology
Journals in engineering geology, earth science, environment, ...
Engineering Geology
Course outcome: The student will be trained to know the description of soil and rock masses
for engineering purposes and is also expected to know the following:
1. Engineering geological maps and its applications.
2. Rock engineering properties and the geotechnical problems they cause.
3. The various techniques for soil and rock improvement.
Scheme of assessment:
3 exams:
30%
Field Trip:
10%
Attendance:
10%
Lab work:
25%
Final exam:
25%
EEG 341 ﻣﻘﺮر اﻟﺠﻴﻮﻟﻮﺟﻴﺎ اﻟﻬﻨﺪﺳﻴﺔ
ﺟﺎﻣﻌﺔ اﻟﻤﻠﻚ ﻋﺒﺪاﻟﻌﺰﻳﺰ
١
آﻠﻴﺔ ﻋﻠﻮم اﻷرض
أد/ ﻋﺒﺎس ﺑﻦ ﻋﻴﻔﺎن اﻟﺤﺎرﺛﻲ
ﻗﺴﻢ اﻟﺠﻴﻮﻟﻮﺟﻴﺎ اﻟﻬﻨﺪﺳﻴﺔ و اﻟﺒﻴﺌﻴﺔ
3. Time Table for Course Lectures
Week
1
2
3
Test Name
Introduction: Definition, purpose and scope
The broad scope of engineering geology
Functions of engineering geology
References
See above
First Exam
4
5
6
7
8
9
10
11
12
13
14
15
Types of Maps
Engineering geological map. Geohazards maps
Comparison between geological and engineering
maps,.
Description and classification systems of soil
Second Exam
Description and classification systems of Rocks
BGD system
Geological Society system
IAEG system, RMR system
Third Exam
Requirement
of
conducting
Engineering
Geological studies,
Engineering Geological
Reports
Rock and soil improvement such as grouting,
drains and reinforcement of ground
Rock and soil improvement such as grouting,
drains and reinforcement of ground
16
Final Exam
EEG 341 ﻣﻘﺮر اﻟﺠﻴﻮﻟﻮﺟﻴﺎ اﻟﻬﻨﺪﺳﻴﺔ
ﺟﺎﻣﻌﺔ اﻟﻤﻠﻚ ﻋﺒﺪاﻟﻌﺰﻳﺰ
٢
آﻠﻴﺔ ﻋﻠﻮم اﻷرض
أد/ ﻋﺒﺎس ﺑﻦ ﻋﻴﻔﺎن اﻟﺤﺎرﺛﻲ
ﻗﺴﻢ اﻟﺠﻴﻮﻟﻮﺟﻴﺎ اﻟﻬﻨﺪﺳﻴﺔ و اﻟﺒﻴﺌﻴﺔ
4. Time Table for Course Lab Work
Week
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
Test Name
Review: Engineering properties of soils and rock.
Flowchart function
Types of Maps
Exam 1
Classification of engineering geological maps
Single purpose map
Multipurpose & Comprehensive Maps
Soil Classification( USCS)
Exam 2
Description and classification systems of Rocks (Review)
Zonation BGD – system
Rock Mass Description System by GS
Rock and Soil Descrip. & Class. For Eng. Geol. Mapping
(IAEG)
RMR System
Exam 3
Conducting Engineering geological study
Example of Writing Eng. Geol. reports
Lab Final Exam
EEG 341 ﻣﻘﺮر اﻟﺠﻴﻮﻟﻮﺟﻴﺎ اﻟﻬﻨﺪﺳﻴﺔ
ﺟﺎﻣﻌﺔ اﻟﻤﻠﻚ ﻋﺒﺪاﻟﻌﺰﻳﺰ
٣
آﻠﻴﺔ ﻋﻠﻮم اﻷرض
References
أد/ ﻋﺒﺎس ﺑﻦ ﻋﻴﻔﺎن اﻟﺤﺎرﺛﻲ
ﻗﺴﻢ اﻟﺠﻴﻮﻟﻮﺟﻴﺎ اﻟﻬﻨﺪﺳﻴﺔ و اﻟﺒﻴﺌﻴﺔ
5. ﻗﺴﻢ اﻟﺠﻴﻮﻟﻮﺟﻴﺎ اﻟﻬﻨﺪﺳﻴﺔ و اﻟﺒﻴﺌﻴﺔ
ﺭﻤﺯ ﺍﻟﻤﻘﺭﺭ:- ﺽ ﺠﻪ
ﺭﻗﻡ ﺍﻟﻤﻘﺭﺭ ١٤٣
ﺍﻟﻤﺘﻁﻠﺒﺎﺕ ﺍﻟﺴﺎﺒﻘﺔ ﺽ ﺠﻪ ١١٣ ﻭ ﺽ ﺠﻪ ٢٢٣
ﻭﺼﻑ ﺍﻟﻤﻘﺭﺭ:-
ﺘﻌﺭﻴﻑ ﺍﻟﺠﻴﻭﻟﻭﺠﻴﺎ ﺍﻟﻬﻨﺩﺴﻴﺔ ، ﺍﻫﺘﻤﺎﻤﺎﺘﻬﺎ ﻭ ﻤﺠﺎﻻﺕ ﺃﻋﻤﺎﻟﻬﺎ، ﺍﻻﻋﺘﺒﺎﺭﺍﺕ ﺍﻟﺠﻴﻭﻟﻭﺠﻴﺔ ﺍﻟﻬﻨﺩﺴﻴﺔ ، ﺍﻟﺨﺭﺍﺌﻁ
ﺍﻟﺠﻴﻭﻟﻭﺠﻴﺔ ﺍﻟﻬﻨﺩﺴﻴﺔ ﻭ ﺃﻨﻭﺍﻋﻬﺎ، ﺃﻨﻅﻤﺔ ﻭ ﺼﻑ ﻭ ﺘﺼﻨﻴﻑ ﺍﻟﺘﺭﺒﺔ ، ﺃﻨﻅﻤﺔ ﻭ ﺼﻑ ﻭ ﺘﺼـﻨﻴﻑ ﺍﻟﻜﺘـل
ﺍﻟﺼﺨﺭﻴﺔ ﻭﺭﺴﻡ ﺍﻟﺨﺭﺍﺌﻁ ﺍﻟﺠﻴﻭﻟﻭﺠﻴﺔ ﺍﻟﻬﻨﺩﺴﻴﺔ ﻭ ﻜﺘﺎﺒﺔ ﺍﻟﺘﻘﺎﺭﻴﺭ. ﺍﻟﻤﺸﺎﻜل ﺍﻟﻬﻨﺩﺴﻴﺔ ﻓﻲ ﺍﻟﺘﺭﺒﺔ ﻭ ﺍﻟﺼﺨﻭﺭ
ﻭﻁﺭﻕ ﻤﻌﺎﻟﺠﺘﻬﺎ.
اﻟﻤﺮاﺟﻊ اﻟﻌﻠﻤﻴﺔ ﻟﻠﻤﻘﺮر
.0891 ,.1. Engineering Geology and Geotechnics by BELL, F. G
,.2. Engineering Geology: Rock Engineering in Construction by GOODMAN, R.E
3991
6891 ,.3. Engineering Geology: An Environmental Approach by RAHN, P. H
6791 ,.4. Engineering Geology by ZARUBA, Q., and MENCL, V
:Internet links
Geology and Geological Engineering
Geotechnical and Geoenvironmental Software Directory
.Geophex, Ltd
GeoLine
SpringerLink: Bulletin of Engineering Geology and the Engineering Geology
... ,Journals in engineering geology, earth science, environment
Engineering Geology
اﻟﻤﻄﻠﻮب ﻣﻦ اﻟﻤﻘﺮر:-
١- ﻓﻬﻢ اﻟﻄﺎﻟﺐ ﻟﻠﺠﻴﻮﻟﻮﺟﻴﺎ اﻟﻬﻨﺪﺳﻴﺔ و اهﺪاﻓﻬﺎ و ﻣﺠﺎﻻت ﻋﻤﻠﻬﺎ
٢- ﻣﻌﺮﻓﺘﻪ ﺑﺎﻧﻮاع اﻟﺨﺮاﺋﻂ اﻟﻬﻨﺪﺳﻴﺔ واﻧﻈﻤﺔ رﺳﻤﻬﺎ و ﺗﺼﻨﻴﻔﻬﺎ
٣- ﺗﻄﺒﻴﻖ اﻧﻈﻤﺔ و ﺻﻒ و ﺗﺼﻨﻴﻒ اﻟﺘﺮﺑﺔ و اﻟﺼﺨﻮر ﻟﻸﻏﺮاض اﻟﻬﻨﺪﺳﻴﺔ و ﻟﺮﺳﻢ اﻟﺨﺮاﺋﻂ اﻟﺠﻴﻮﻟﻮﺟﻴﺔ اﻟﻬﻨﺪﺳﻴﺔ.
٤- ﻣﻌﺮﻓﺔ ﻃﺮق اﺟﺮاء اﻟﺪراﺳﺎت و آﺘﺎﺑﺔ اﻟﺘﻘﺎرﻳﺮ ﻓﻲ ﻣﺠﺎل اﻟﺠﻴﻮﻟﻮﺟﻴﺎ اﻟﻬﻨﺪﺳﻴﺔ.
٥- اﻟﺘﻌﺮف ﻋﻠﻰ اﻟﻤﺸﺎآﻞ اﻟﻬﻨﺪﺳﻴﺔ ﻟﻠﺘﺮﺑﺔ و اﻟﺼﺨﻮر وﻃﺮق ﻣﻌﺎﻟﺠﺘﻬﺎ.
.
ﻃﺮق اﻟﺘﻘﻴﻴﻢ و ﺗﻮزﻳﻊ اﻟﺪرﺟﺎت:
%03
%01
%01
%52
%52
أد/ ﻋﺒﺎس ﺑﻦ ﻋﻴﻔﺎن اﻟﺤﺎرﺛﻲ
ﻗﺴﻢ اﻟﺠﻴﻮﻟﻮﺟﻴﺎ اﻟﻬﻨﺪﺳﻴﺔ و اﻟﺒﻴﺌﻴﺔ
٤
آﻠﻴﺔ ﻋﻠﻮم اﻷرض
:3 exams
:Field Trip
:Attendance
:Lab work
:Final exam
ﻣﻘﺮر اﻟﺠﻴﻮﻟﻮﺟﻴﺎ اﻟﻬﻨﺪﺳﻴﺔ 143 EEG
ﺟﺎﻣﻌﺔ اﻟﻤﻠﻚ ﻋﺒﺪاﻟﻌﺰﻳﺰ
10. Definition and Scope of Engineering Geology
Engineering geology forms the bridge between geology and engineering. It is mainly
concerned with the application of geology to civil and mining engineering practice. The
purpose is to ensure that geological factors affecting the planning, design construction
and maintenance of engineering works and the development of groundwater resources are
recognized, adequately interpreted and presented for use in engineering practice.
: ﺗﻌﺮﻳﻒ
اﻟﺠﻴﻮﻟﻮﺟﻴﺎ اﻟﻬﻨﺪﺳﻴﺔ هﻲ اﻟﺮاﺑﻂ ﺑﻴﻦ اﻟﻤﻮاد اﻟﺠﻴﻮﻟﻮﺟﻴﺔ ) اﻟﺼﺨﻮر واﻟﺘﺮﺑﺔ ( واﻷﻋﻤﺎل اﻟﻬﻨﺪﺳﻴﺔ واﻷﺧﺬ ﻓﻲ اﻻﻋﺘﺒﺎر
اﻟﻌﻮاﻣﻞ اﻟﺠﻴﻮﻟﻮﺟﻴﺔ اﻟﻤﺆﺛﺮة ﻋﻠﻰ
٤- اﻟﺼﻴﺎﻧﺔ
٣- اﻟﺒﻨﺎء
٢- اﻟﺘﺼﻤﻴﻢ
١- اﻟﺘﺨﻄﻴﻂ
In engineering geology basic knowledge is required of the following:
- General Geology
- Surveying
- Geomorphology
- Remote Sensing
- Hydrology
-Seismic, Geophysics
- Soil Mechanics
- Rock Mechanics
- Concrete, Aggregate
- Foundation
- Road pavement of construction
A Much greater knowledge is required of site in investigation practice such as :
Boring
Engineering geophysics
Sampling
Photo geology
Lab in situ testing
Engineering geological mapping
This knowledge is printed on background of with emphasis on structural geology ,
geomorphology , Sediment logy And there must be information on the use of computers
in data analysis and geological mapping .
Functions of Engineering Geologist
The engineering geologist can contribute on the followings;
Interpretation of the ground conditions
Exploration and assessment
Identification of hazards
EEG 341 ﻣﻘﺮر اﻟﺠﻴﻮﻟﻮﺟﻴﺎ اﻟﻬﻨﺪﺳﻴﺔ
ﺟﺎﻣﻌﺔ اﻟﻤﻠﻚ ﻋﺒﺪاﻟﻌﺰﻳﺰ
٩
آﻠﻴﺔ ﻋﻠﻮم اﻷرض
أد/ ﻋﺒﺎس ﺑﻦ ﻋﻴﻔﺎن اﻟﺤﺎرﺛﻲ
ﻗﺴﻢ اﻟﺠﻴﻮﻟﻮﺟﻴﺎ اﻟﻬﻨﺪﺳﻴﺔ و اﻟﺒﻴﺌﻴﺔ
17. ﻤﺜﺎل
Example of Description
BGD
1-Rock Name
2- Layer Thickness
L
3- Fracture Intercept
F
4-Uniaxial Compressive Strength
S
5- Friction Angle
A
Classification Example of
RMR ﻣﺜﺎل ﻋﻠﻰ
Rating
UCU
٢٠
RQD
٢٠
j.S
١٥
Joint Condition
٣٠
Ground Water
٥
Total RMR =90
EEG 341 ﻣﻘﺮر اﻟﺠﻴﻮﻟﻮﺟﻴﺎ اﻟﻬﻨﺪﺳﻴﺔ
ﺟﺎﻣﻌﺔ اﻟﻤﻠﻚ ﻋﺒﺪاﻟﻌﺰﻳﺰ
١٦
آﻠﻴﺔ ﻋﻠﻮم اﻷرض
أد/ ﻋﺒﺎس ﺑﻦ ﻋﻴﻔﺎن اﻟﺤﺎرﺛﻲ
ﻗﺴﻢ اﻟﺠﻴﻮﻟﻮﺟﻴﺎ اﻟﻬﻨﺪﺳﻴﺔ و اﻟﺒﻴﺌﻴﺔ
18. A- Soil and Rock Description classification system
For Engineering Purposes
1- Soil Description and classification system
Unified Soil Classification System (U S C S)
BY: Terzaghi and peck 1968
Engineering proper ties of (U S C S)
1. Soil type
2. Grain size
3. Soil texture
4. Soil color
5. Cc _Cu
6. Strength
7. LL _PL
2- Rock description and classification Systems
Description
a- Basic Geotechnical
b- Rock Mass Description of
Description of Rock
Engineering purpose
Masses (BGD)
BY: Engineering Group
BY: International Society Geological Society (GS) 1972
Rock material Discontinuity
of Rock Mechanics
1. Rock type
1. type
(ISRM) 1981
2. sets no
2. Color
1. Rock name
3. Grain size 3. Joint spacing
2. Layer thickness (L)
4. orientation
3. Fracture intercepts (F) 4. Strength
Dip / Dip direction
4. Uniaxial Compressive
Strength (UCS)
5. Angle of friction(A)
classification
a- Rock Mass Rating (RMR)
BY:Bieniawski 1974
1. Strength
2.Rock Quality Designation
(RQD)
3. Spacing of Joint (J.S)
4. condition of Discontinuity
5. ground water
B- Soil and Rock Mass Description and classification system
For Engineering Geological Mapping
Rock and soil description and classification for engineering geological
mapping. Bulletin of the International Association of Engineering
Geology, No. 24, pp. 235-244.
EEG 341 ﻣﻘﺮر اﻟﺠﻴﻮﻟﻮﺟﻴﺎ اﻟﻬﻨﺪﺳﻴﺔ
ﺟﺎﻣﻌﺔ اﻟﻤﻠﻚ ﻋﺒﺪاﻟﻌﺰﻳﺰ
١٧
آﻠﻴﺔ ﻋﻠﻮم اﻷرض
أد/ ﻋﺒﺎس ﺑﻦ ﻋﻴﻔﺎن اﻟﺤﺎرﺛﻲ
ﻗﺴﻢ اﻟﺠﻴﻮﻟﻮﺟﻴﺎ اﻟﻬﻨﺪﺳﻴﺔ و اﻟﺒﻴﺌﻴﺔ
19. Soil Classification and Description
Soil Description :1- Soil Type .
2- Soil Color .
3- Mineral Composition .
4- Strength (Consistency) , Density .
Type of Soils :1- Sand . , 2- Silt . 3- Clay . 4- Sabkhah . 5- Mixed (Gravel, Sand, Silt, Clay)
-: * ﻣﺜﺎل ﻟﺒﻌﺾ أﻟﻮان اﻟﺘﺮﺑﺔ و ﻣﻌﺮﻓﺔ ﺗﺮآﻴﺒﻬﺎ اﻟﻤﻌﺪﻧﻲ
- Yellowish Red (Granite : Mineral Composition : K- feldspar – Plagioclase)
- Black – Gray (Diorite – Gabbro : Mineral Composition : Biotite – Muscovite)
- Yellow – Beige (Clay – Dolomite)
: و ﻣﺜﺎل ﻟﺘﺼﻨﻴﻔﻬﺎ
SW
,
SP
,
CL
4- SPT (Standard Penetration Test) :N
- Very Dense.
- Dense.
- Medium Dense.
- Loose.
- Very Loose.
• Soil Description :- -: ﻣﺜﺎل ﻟﻠﻮﺻﻒ
- Sand = Yellow. Dense, Angular, Very Loose. SW 0 – 15 % Relative Density.
ASTM (1985a). Standard practice for description and identification of
soils (visual-manual) procedure. Test designation D2488-84. 1985
Annual Book of ASTM Standards, American Society of Testing and
Materials, Philadelphia, Vol.04.08, pp. 409-423.
ASTM (1985b). Standard test method for classification of soils for
engineering purposes. Test Designation D2487-83. 1985 Annual Book of
ASTM Standards, American Society of Testing and Materials,
Philadelphia, Vol. 04.08, pp. 395-408.
EEG 341 ﻣﻘﺮر اﻟﺠﻴﻮﻟﻮﺟﻴﺎ اﻟﻬﻨﺪﺳﻴﺔ
ﺟﺎﻣﻌﺔ اﻟﻤﻠﻚ ﻋﺒﺪاﻟﻌﺰﻳﺰ
١٨
آﻠﻴﺔ ﻋﻠﻮم اﻷرض
أد/ ﻋﺒﺎس ﺑﻦ ﻋﻴﻔﺎن اﻟﺤﺎرﺛﻲ
ﻗﺴﻢ اﻟﺠﻴﻮﻟﻮﺟﻴﺎ اﻟﻬﻨﺪﺳﻴﺔ و اﻟﺒﻴﺌﻴﺔ
20. Soil Description
The sequence of describing a soil sample is as follows:
a) Compactness and consistency
b) Color
c) Descriptive term
d) Soil identification (Major constituents)
e) Soil identification (Minor constituents)
f) Water content descriptive term.
a) Compactness and consistency: (stiffness or density)
b) Color: the soil colors provide information of soil minerals and
environments.
•
•
•
•
•
•
•
Red: Indicates iron oxide
Pale Yellow: Hydrated iron oxide
Black: Organic soils
Dark brown: due to dark
Gray: (manganese, magnetite)
Green: Glauconitic
White: Silica, gypsum, kaoline clay.
In general use only basic colors. Describe soils with different shades of basic
colors by using two basic colors; e.g. Gray brown.
“Mottled” means marked with spots of color while "streaked" means
having color patterns which cannot be considered spotted.
c)Descriptive term:
• Coarse grained soils
i. Use angular, subangular, rounded etc. to indicate the shape of the
grains
ii. Use coarse medium, fine, coarse to fine, or medium to fine to
indicate grain size distribution of the samples.
• Fine grained soils
Use brittle, friable, spongy, sticky, fissured, fibrous, etc. if
applicable.
EEG 341 ﻣﻘﺮر اﻟﺠﻴﻮﻟﻮﺟﻴﺎ اﻟﻬﻨﺪﺳﻴﺔ
ﺟﺎﻣﻌﺔ اﻟﻤﻠﻚ ﻋﺒﺪاﻟﻌﺰﻳﺰ
١٩
آﻠﻴﺔ ﻋﻠﻮم اﻷرض
أد/ ﻋﺒﺎس ﺑﻦ ﻋﻴﻔﺎن اﻟﺤﺎرﺛﻲ
ﻗﺴﻢ اﻟﺠﻴﻮﻟﻮﺟﻴﺎ اﻟﻬﻨﺪﺳﻴﺔ و اﻟﺒﻴﺌﻴﺔ
21. • Other descriptive terms applicable to both fine grained and coarse
grained soils are : with occasional, with frequent, pockets of,
layers of, seams of, lenses of, etc.
These will follow the soil identification.
d) Soils identification: (Major constituents)
Identify the major matrix of the soil sample and write this in Capital
letters e.g. GRAVEL, SAND, SILT, CLAY.
e) Soils identification: (Minor constituents)
Identify the minor matrix of the soil sample and write this in small letters
e.g. gravely , Sandy, Silty , Clayey.
f) Water content descriptive term.
Seepage, Wet, Dump, Dry, very Dry
Examples:
Sand : Dense, brown, subangular medium grained, trace silt, with pockets
of clay.
Gravel : Very dense, gary, angular fine grained, some sand and trace silt,
with seems of clay.
Silty Sand : Medium dense, gray brown, subrounded medium grained
with trace gravel and lenses of clay
clay : Stiff, dark gray, sticky with some silt.
Soil Classification:
Unified Soil Classification System BY: Terzaghi and peck 1968
It includes:- 1. Soil type , 2. Grain size, 3. Soil texture, 4. Soil color, 5. Cc, Cu 6. Strength, 7. LL -PL
Sieve analysis test is a test to determine gradation, which is common mean for describing the
particle size distribution present in a soil. It is applied to the soil fraction consisting of gravel,
sand, silt, and clay particles.
Soil Types:- (1) Cohesion:- CLAY
(2) Cohesionless:- GRAVEL, SAND, SILT
Cu Coefficient of uniformity = D60 / D10
Cc Coefficient of curvature = (D30)2 / (D10*D60)
Soil Strength :- The Standard Penetration Test (SPT) is useful in determining certain
properties of soils, particularly of cohesionless soils, for which undisturbed samples are not
easily obtained. SPT (Standard Penetration Test) :-Very Dense, Dense, Medium Dense. Loose
Very Loose.
Plastic Limit, PL, and Liquid Limit, LL are engineering properties for clays.
EEG 341 ﻣﻘﺮر اﻟﺠﻴﻮﻟﻮﺟﻴﺎ اﻟﻬﻨﺪﺳﻴﺔ
ﺟﺎﻣﻌﺔ اﻟﻤﻠﻚ ﻋﺒﺪاﻟﻌﺰﻳﺰ
٢٠
آﻠﻴﺔ ﻋﻠﻮم اﻷرض
أد/ ﻋﺒﺎس ﺑﻦ ﻋﻴﻔﺎن اﻟﺤﺎرﺛﻲ
ﻗﺴﻢ اﻟﺠﻴﻮﻟﻮﺟﻴﺎ اﻟﻬﻨﺪﺳﻴﺔ و اﻟﺒﻴﺌﻴﺔ
26. The description of rock masses for engineering purposes
By
Geological Society
(GS)
[ Engineering Group] Working Party .
: اﻟﺨﻮاص اﻟﺘﻲ ﻳﻌﺘﻤﺪ ﻋﻠﻴﻬﺎ هﺬا اﻟﺘﺼﻨﻴﻒ
By the Geological Society (Gs)(Engineering Group) Working
Party, 1977
Properties of Intact Rock
Description:
Properties of Rock Mass
Description:
1‐
2‐
3‐
4‐
5‐
1‐ Types
2‐ Numbers of
discontinuity sets
3‐ Location and orientation
4‐ Spacing between
adjacent discontinuities
5‐ Aperture of
discontinuity surface
6‐ Infilling
7‐ Persistence or extent
8‐ Nature of surface
Rock type
Color
Grain size
Texture and fabric
Weathered and altered
state
6‐ Strength
Geological Society (1972). The preparation of maps and plans in terms of
engineering geology. Geological Society Engineering Group Working Party
Report, Quarterly Journal of Engineering Geology, Vol.5, pp. 295-381.
Geological Society (1977). The description of rock masses for engineering
purposes. Geological Society Engineering Group Working Party Report,
Quarterly Journal of Engineering Geology, Vol.10, pp. 355. و ﺑﻌﺪ إﻳﺠﺎد اﻟﺨﻮاص اﻟﺴﺎﺑﻘﺔ و ﺗﺮﺗﻴﺒﻬﺎ ﻓﻲ ﺟﺪول ﺗﻮﺻﻒ ﻓﻲ وﺻﻒ آﺘﺎﺑﻲ
EEG 341 ﻣﻘﺮر اﻟﺠﻴﻮﻟﻮﺟﻴﺎ اﻟﻬﻨﺪﺳﻴﺔ
ﺟﺎﻣﻌﺔ اﻟﻤﻠﻚ ﻋﺒﺪاﻟﻌﺰﻳﺰ
٢٥
آﻠﻴﺔ ﻋﻠﻮم اﻷرض
أد/ ﻋﺒﺎس ﺑﻦ ﻋﻴﻔﺎن اﻟﺤﺎرﺛﻲ
ﻗﺴﻢ اﻟﺠﻴﻮﻟﻮﺟﻴﺎ اﻟﻬﻨﺪﺳﻴﺔ و اﻟﺒﻴﺌﻴﺔ
29. Rock and soil description and classification for engineering
geological mapping
IAEG (1981). Rock and soil description and classification for
engineering geological mapping. Bulletin of the International Association
.442-532 .of Engineering Geology, No. 24, pp
أول ﻣﺎ ﻳﺘﻢ ﻋﻤﻠﻪ ﻣﻦ ﻗﺒﻞ اﻟﺠﻴﻮﻟﻮﺟﻲ اﻟﻬﻨﺪﺳﻲ :-
١- اﻟﺨﺮوج ﻟﻠﻤﻮﻗﻊ و ﻓﺤﺼﻪ .
٢- اﻹآﺘﺸﺎف و اﻟﺘﻘﻴﻴﻢ و إﺟﺮاء اﻟﺘﺠﺎرب اﻟﺤﻘﻠﻴﺔ و اﻟﻤﻌﻤﻠﻴﺔ .
٣- ﺗﻌﻴﻴﻦ اﻟﻤﺨﺎﻃﺮ و ﺗﺤﺪﻳﺪ اﻟﻨﻄﺎﻗﺎت ورﺳﻢ اﻟﺨﺮاﺋﻂ اﻟﺠﻴﻮﻟﻮﺟﻴﺔ اﻟﻬﻨﺪﺳﻴﺔ و ﻣﻦ ﺛﻢ آﺘﺎﺑﺔ اﻟﺘﻘﺮﻳﺮ.
أد/ ﻋﺒﺎس ﺑﻦ ﻋﻴﻔﺎن اﻟﺤﺎرﺛﻲ
ﻗﺴﻢ اﻟﺠﻴﻮﻟﻮﺟﻴﺎ اﻟﻬﻨﺪﺳﻴﺔ و اﻟﺒﻴﺌﻴﺔ
٨٢
آﻠﻴﺔ ﻋﻠﻮم اﻷرض
ﻣﻘﺮر اﻟﺠﻴﻮﻟﻮﺟﻴﺎ اﻟﻬﻨﺪﺳﻴﺔ 143 EEG
ﺟﺎﻣﻌﺔ اﻟﻤﻠﻚ ﻋﺒﺪاﻟﻌﺰﻳﺰ
30. Material Improvement
The soil and rock improvement will include two parts;
(A) Grouting,
and
(B) Deep Compaction.
A) Grouting
A.1 Definition:
Injection of fluid material under pressure to improve the geotechnical character
of soil and rocks and to stop or reduce water movement.
Grouting is expensive and time consuming process.
A.2 Purpose:
Grout are used to
1. improve the quality of soil and rocks in dams, tunnel, slopes, mines
and foundation. The main purpose are:
2. increase the strength by cementing the particles (cohesion)
3. prevent water by reduce pore water pressure and reduce permeability
4. stop water leakage
A.3 Types of Grout:
a) Particles suspensions
Clay grout: clay mixed with water to form colloidal
Suspension. The clay may be bentonite. the strength is low reduce the permeability
•
Clay and cement grout
to increase the strength
keeping the permeability low
Cement grout: the cement water ratio is 3 to 5 to prevent clogging the pores.
Bitumen: cheap grout used mainly for water stop.
b) Grout admixture : Some of the grouts are a mixture of more than one type to
improve the grout quality (Table 1).
Table 1: The properties of some grout admixture
EEG 341 ﻣﻘﺮر اﻟﺠﻴﻮﻟﻮﺟﻴﺎ اﻟﻬﻨﺪﺳﻴﺔ
ﺟﺎﻣﻌﺔ اﻟﻤﻠﻚ ﻋﺒﺪاﻟﻌﺰﻳﺰ
٢٩
آﻠﻴﺔ ﻋﻠﻮم اﻷرض
أد/ ﻋﺒﺎس ﺑﻦ ﻋﻴﻔﺎن اﻟﺤﺎرﺛﻲ
ﻗﺴﻢ اﻟﺠﻴﻮﻟﻮﺟﻴﺎ اﻟﻬﻨﺪﺳﻴﺔ و اﻟﺒﻴﺌﻴﺔ
31. Grout that accelerate setting time
• Cacl2
• NaOH
• Sodium silicate
Grout that reduce setting time
• Gypsum
• lime
Grout that increase plasticity and reduce
Chemical
c)
shrinkage very fine bentonite (volcanic clay)
There
are
grout:
hundred of chemical grouts in the form of powder. The material is mixed with
water in the site. The amount of powder added to water controls the setting
time. The chemical composition is presented in Table 2.
Table 2: The chemical grout
Silicate gel
Resins (Acrylic and
Phenolic)
Phenol-formaldehyde
Acrylate
Resorcinolformaldehyde
Polyacrylamide
Foam
Am-9
DMAPN
Cemex-A
A.4 Site Investigation:
EEG 341 ﻣﻘﺮر اﻟﺠﻴﻮﻟﻮﺟﻴﺎ اﻟﻬﻨﺪﺳﻴﺔ
ﺟﺎﻣﻌﺔ اﻟﻤﻠﻚ ﻋﺒﺪاﻟﻌﺰﻳﺰ
٣٠
آﻠﻴﺔ ﻋﻠﻮم اﻷرض
أد/ ﻋﺒﺎس ﺑﻦ ﻋﻴﻔﺎن اﻟﺤﺎرﺛﻲ
ﻗﺴﻢ اﻟﺠﻴﻮﻟﻮﺟﻴﺎ اﻟﻬﻨﺪﺳﻴﺔ و اﻟﺒﻴﺌﻴﺔ
32. 1. Geology
Rocks: look for fissures, faults, or weakness zones (shear zones)
Soils: Soil type and permeability
2. Geotechnical survey:
2.1 Drilling to discover the soil/rock types and boundaries.
2.2 Soil properties (k)
2.2.1 Permeability: This will tell us how easy
the grouting fluid can penetrate.
Should be determined in boreholes "site"
k =(Q)/ 5.5 r H
Q = volume of flow
r = radius of casing
H = differential head causing flow
2.2.2 Porosity:
It gives an indication of the volume required to fill the soil (rock) with grout fluid.
2.2.3 Borehole size distribution
i.
if 20% passes # 200 grouting is not successful
ii.
grout particles < (1/10) D50
2.2.4 Pore size distribution
Grout particles = soil pore size
A.5 Grout selection:
The correct grout for a given project is selected based on:
The purpose (strength and/or water tightening)
The purpose (strength and/or water tightening)
The material to be treated (soil or rock)
Look Table 7-4 and Table 7-17.
The grout viscosity
The grout grain size
The availability in local market
The setting time
The grout price (Table 7-16).
EEG 341 ﻣﻘﺮر اﻟﺠﻴﻮﻟﻮﺟﻴﺎ اﻟﻬﻨﺪﺳﻴﺔ
ﺟﺎﻣﻌﺔ اﻟﻤﻠﻚ ﻋﺒﺪاﻟﻌﺰﻳﺰ
٣١
آﻠﻴﺔ ﻋﻠﻮم اﻷرض
أد/ ﻋﺒﺎس ﺑﻦ ﻋﻴﻔﺎن اﻟﺤﺎرﺛﻲ
ﻗﺴﻢ اﻟﺠﻴﻮﻟﻮﺟﻴﺎ اﻟﻬﻨﺪﺳﻴﺔ و اﻟﺒﻴﺌﻴﺔ
33. Example (1): If the ground k-value is 5x10-3 m/s. What is the grout type if it the
purpose is to increase strength.
The selection of grout material based on (Figure 5.5):
(1)
(2)
(3)
Purpose.
material to be treated (soil).
Permeability.
Answer : the grout is Asphalt Emulsion
Fig. 5-5. Grout applications in loose soil.
A.6 Ground Treatment: Following the selection of the grout type and ground,
the area to be treated should be estimated (in square meters) and the depth of
the treatment. Grouting is conducted in the following steps;
Select the suitable grout type based on the properties and condition
of the ground to be treated (Figure 5.5, Table 7.4, Tables 4.1-4.2 ). Check
again the grout suitability based on prices (Tables 7-16).
The grout is injected to the ground inside drill holes. The standard of
the boreholes is shown in Figure 7.39. The depth of the drilling depends on
the thickness of the layer to be treated (5 or 10 m deep).
The spacing of the drill holes depends on the type of ground material,
soil or rock (Table 7.9).
The volume of the grout depends on the porosity of soil ( !) or the
estimation of the fracture size in rocks.
Example (2): Fine sand under a dam is to be treated to increase the
٣٢
EEG 341 ﻣﻘﺮر اﻟﺠﻴﻮﻟﻮﺟﻴﺎ اﻟﻬﻨﺪﺳﻴﺔ
أد/ ﻋﺒﺎس ﺑﻦ ﻋﻴﻔﺎن اﻟﺤﺎرﺛﻲ
ﺟﺎﻣﻌﺔ اﻟﻤﻠﻚ ﻋﺒﺪاﻟﻌﺰﻳﺰ
آﻠﻴﺔ ﻋﻠﻮم اﻷرض
ﻗﺴﻢ اﻟﺠﻴﻮﻟﻮﺟﻴﺎ اﻟﻬﻨﺪﺳﻴﺔ و اﻟﺒﻴﺌﻴﺔ
34. strength. The ground surface area is 55 by 25 m, and treatment should be to
a depth of 5 m. The soil permeability
(k) is 5x10 m/s. The soil porosity (n) is 0.25. The cost of
cement is SR 60 per m 3 , the relative cost of the grout to be used is 1.5.
Determine
• The grout type to be used
• The volume of the grout
• The total cost of the grout
Solution
(1) Use
Figure 5.5 to determine the grout type based on k value and
purpose (strengthening). ..... the suitable grout is Silicate gel (for
strengthening).
volume of the treated soil is 55x25x5 m 3 ( 6,875 m3). The volume of
the grout depend on the soil porosity (n=0.25), then the
volume of the grout (Vg ) is
(2) The
Vg . 6,875 x 0.25 = 1,718.75 m3
The total grout cost can be estimated as follow: - the grout volume is
1,718.75 m3
- the cost of cement is SR 60 per m3, which means that if the used grout was
cement then it cost :
60 x 1,718 = SR 103,125
(But remember that we did not use cement).
- the selected grout relative cost is 1.5, then the cost of the selected grout is:
(3)
103,125 x 1.5 = SR 54,687.5
EEG 341 ﻣﻘﺮر اﻟﺠﻴﻮﻟﻮﺟﻴﺎ اﻟﻬﻨﺪﺳﻴﺔ
ﺟﺎﻣﻌﺔ اﻟﻤﻠﻚ ﻋﺒﺪاﻟﻌﺰﻳﺰ
٣٣
آﻠﻴﺔ ﻋﻠﻮم اﻷرض
أد/ ﻋﺒﺎس ﺑﻦ ﻋﻴﻔﺎن اﻟﺤﺎرﺛﻲ
ﻗﺴﻢ اﻟﺠﻴﻮﻟﻮﺟﻴﺎ اﻟﻬﻨﺪﺳﻴﺔ و اﻟﺒﻴﺌﻴﺔ
35. B) Deep Compaction:
This method is restricted to soil only. The main types of deep compaction are;
B-1 Static Compaction
B-2 Dynamic compaction
B-3 Vibrofloatation
B-4 Deep blasting
B-1
Static Compaction
This method is slowing arid used for fine grained soil (silt and clay). Large
and heavy rectangular concrete are placed on the soil for months and the
soil settlement is monitored.
EEG 341 ﻣﻘﺮر اﻟﺠﻴﻮﻟﻮﺟﻴﺎ اﻟﻬﻨﺪﺳﻴﺔ
ﺟﺎﻣﻌﺔ اﻟﻤﻠﻚ ﻋﺒﺪاﻟﻌﺰﻳﺰ
٣٤
آﻠﻴﺔ ﻋﻠﻮم اﻷرض
أد/ ﻋﺒﺎس ﺑﻦ ﻋﻴﻔﺎن اﻟﺤﺎرﺛﻲ
ﻗﺴﻢ اﻟﺠﻴﻮﻟﻮﺟﻴﺎ اﻟﻬﻨﺪﺳﻴﺔ و اﻟﺒﻴﺌﻴﺔ
36. B-2
Dynamic compaction (Menard, 1972)
Weight of bounder (Wx) = 5 to 40 tons Dropping height (hx) = 10 to 40 m
Energy = 4000 ft-ton
Crater depth 1 to 3 m
Effective depth (De) can be calculated from;
De = (Wx hx)'/2
The average De is about 10 to 15 m
B-3
Vibrofloatation
Good for loose granular soils by rearranging loose cohesionless grains into
denser array (Figure 4.5). It is more suitable where explosions can not be used.
The degree of suitability depends on the soil PI as follow;
Degree of suitability
Fair to good
Not suitable
PI
Good to excellent
0 to less than 8
more than 8
0
B- 4 Deep blasting
EEG 341 ﻣﻘﺮر اﻟﺠﻴﻮﻟﻮﺟﻴﺎ اﻟﻬﻨﺪﺳﻴﺔ
ﺟﺎﻣﻌﺔ اﻟﻤﻠﻚ ﻋﺒﺪاﻟﻌﺰﻳﺰ
٣٥
آﻠﻴﺔ ﻋﻠﻮم اﻷرض
أد/ ﻋﺒﺎس ﺑﻦ ﻋﻴﻔﺎن اﻟﺤﺎرﺛﻲ
ﻗﺴﻢ اﻟﺠﻴﻮﻟﻮﺟﻴﺎ اﻟﻬﻨﺪﺳﻴﺔ و اﻟﺒﻴﺌﻴﺔ
37. Explosive compaction is carried out by setting off explosive charges in the
ground. The energy released causes liquefaction of the soil close to the blast
point and causes cyclic straining of the soil. This cyclic strain process increases
pore water pressures and provided strain amplitudes and numbers of cycles
of straining are sufficient, the soil mass liquefies (i.e. pore water pressures
are temporarily elevated to the effective vertical overburden stress in the soil
mass so that a heavy fluid is created).
Experience has indicated that the degree of ground improvement obtained
by blasting depends on the initial density of the granular subsoils. The
density of loose deposits can typically increase considerably to relative
densities in the range of 70 to 80%, whereas soils with initial relative densities
of 60 to 70% can only be densified by a small amount. Our experience also
indicates that EC generally causes volume changes equal to or in excess of
what would be anticipated under design levels of earthquake shaking, as
described in the attached reference paper by Gohl et al (2000).
The radius of the effected area (r) is:
r = (w)1/3 C
where
r = radial distance
w = charge weight of explosive
C = charge factor depending on the soil type
Example: if
Wt 6 x 1.2 kg charge
Depth 7 m
Soil is loose sand ------ this will give
Settlement of 0.4 m and 10 m effective depth
EEG 341 ﻣﻘﺮر اﻟﺠﻴﻮﻟﻮﺟﻴﺎ اﻟﻬﻨﺪﺳﻴﺔ
ﺟﺎﻣﻌﺔ اﻟﻤﻠﻚ ﻋﺒﺪاﻟﻌﺰﻳﺰ
٣٦
آﻠﻴﺔ ﻋﻠﻮم اﻷرض
أد/ ﻋﺒﺎس ﺑﻦ ﻋﻴﻔﺎن اﻟﺤﺎرﺛﻲ
ﻗﺴﻢ اﻟﺠﻴﻮﻟﻮﺟﻴﺎ اﻟﻬﻨﺪﺳﻴﺔ و اﻟﺒﻴﺌﻴﺔ
40. 1.Compaction
Soil is extensively used as a basic material of construction. For example: dams, dikes,
embankments, ramps, etc. The advantages of using soil are that it (1) is generally
available everywhere, (2) is durable – it will last a long time, and (3) has a
comparatively low cost.
It is typically placed in layers (sometimes called lifts) with each layer being
compacted to develop a final elevation and/or shape.
Why Does It Need Compacted?
Compaction increases a soils density. This produces the following effects:
1. increases the soil’s shear strength
2. decreases future settlement
3. decreases the soil’s permeability (also a function of soil type)
4. stable against volume change as water content or other factors change
5. relatively durable and safe against deterioration
It is most appropriate to talk about a compaction energy. The compaction energy
given to a soil is proportional to the pressure, speed of rolling, and the number of
times it is rolled. A unique aspect of soil is encountered when one wants to maximize
the density but minimize the compaction energy – which makes good business sense.
For a given compaction energy, there is an optimum water content that will obtain a
maximum dry density. Too little or too much water content will cause a smaller dry
density. The water acts as a lubricant and allows the soil particles to squeeze together
more easily.
The Standard Proctor Test is a laboratory test used to determine the optimum water
for a given compaction energy, for a given soil. The graph below illustrate the results
obtained from a Standard Proctor test:
Quick glance at the Standard Proctor test procedures (ASTM D 1557): (1) dry
sample until friable (easily crumbled) with trowel (2) prepare at least 4 samples using
the same soil but different moisture contents (3) wait for a specified curing time (4)
compact (gives a standard energy/vol) (5) measure γ and ω.
EEG 341 ﻣﻘﺮر اﻟﺠﻴﻮﻟﻮﺟﻴﺎ اﻟﻬﻨﺪﺳﻴﺔ
ﺟﺎﻣﻌﺔ اﻟﻤﻠﻚ ﻋﺒﺪاﻟﻌﺰﻳﺰ
٣٩
آﻠﻴﺔ ﻋﻠﻮم اﻷرض
أد/ ﻋﺒﺎس ﺑﻦ ﻋﻴﻔﺎن اﻟﺤﺎرﺛﻲ
ﻗﺴﻢ اﻟﺠﻴﻮﻟﻮﺟﻴﺎ اﻟﻬﻨﺪﺳﻴﺔ و اﻟﺒﻴﺌﻴﺔ
41. Types of compactors (machine images courtesy of Bomag GmbH)
!Error
!Error
Hand
Compactor
(motorized
and nonmotorized)
!Error
!Error
!Error
Walk
Behind
Double
Smooth
Roller
!Error
!Error
Towed Single
Roller
(Vibratory or nonvibratory)
!Error
!Error
Smooth
Roller
(Many times
vibratory)
“Sheepsfoot
”
(Protrusions
!Error
stick out
from
smooth
roller, can
supply
pressures in
excess of
600 psi or
4200
kN/m2)
Walk
Behind
Vibratory
Plate
Walk Behind
Roller
Pneumati
c Roller
(smooth
rubber
tires)
Smooth Roller
!Error
!Error
Grader
(Not a compactor,
but often used in
conjunction with
compactors)
!Error
Heavy
Compactor/Bulldoz
er
(also a “Sheepsfoot”
compactor)
EEG 341 ﻣﻘﺮر اﻟﺠﻴﻮﻟﻮﺟﻴﺎ اﻟﻬﻨﺪﺳﻴﺔ
ﺟﺎﻣﻌﺔ اﻟﻤﻠﻚ ﻋﺒﺪاﻟﻌﺰﻳﺰ
٤٠
آﻠﻴﺔ ﻋﻠﻮم اﻷرض
أد/ ﻋﺒﺎس ﺑﻦ ﻋﻴﻔﺎن اﻟﺤﺎرﺛﻲ
ﻗﺴﻢ اﻟﺠﻴﻮﻟﻮﺟﻴﺎ اﻟﻬﻨﺪﺳﻴﺔ و اﻟﺒﻴﺌﻴﺔ
42. Soil type, water content, and type of compactor are factors that need to be considered
when compacting. Compaction is often used when fill (disturbed soil from another
location and transported) is used at a construction site. This implies you may be using
self-propelled scrapers (earth movers), bulldozers, and graders. An earthcut or
“borrow” is popular to use. A borrow is simply a hole dug (usually near the
construction site) so that soil from this hole is used elsewhere as fill.
Borrows and fill dirt being used at a construction site. Notice the darker top soil with
the lighter subsoil.
Rules of Thumb For Compacting Soils:
I. Granular soils can be compacted in thicker layers (or “lifts) than silt or clay.
II. Fill placed underwater (or requiring good drainage properties) should consist of
granular or coarse material.
III. Check to make sure natural soil is adequate for supporting compacted fill. This
can be tested by rolling over it with a heavy piece of equipment and observing
compaction characteristics (called “proof-rolling”).
IV. Cohesionless soils usually need kneading, tamping, vibratory compacting.
(Note: kneading is defined as working by folding.) Cohesive soils usually need
kneading, tamping, or impact. Heavy cohesive soils can sometimes require dynamic
compacting that uses large weights dropped from heights or underground dynamite
with directed explosions.
Compaction Control Field Testing:
1. Sand Cone – requires hole excavated, weigh the soil removed and determine the
volume of the hole with sand. This is done by filling the hole with a sand of known
density.
2. Washington Densometer – requires hole excavated
3. Oil Replacement – requires hole excavated, weigh the soil removed and determine
the volume of the hole with a device with an expandable rubber membrane
4. Nuclear Densometer – uses a radioactive source and “counter” to determine soil
density. This method has fast results with the potential for a large number of tests in a
short time. It is usually calibrated with the Sand Cone method.
EEG 341 ﻣﻘﺮر اﻟﺠﻴﻮﻟﻮﺟﻴﺎ اﻟﻬﻨﺪﺳﻴﺔ
ﺟﺎﻣﻌﺔ اﻟﻤﻠﻚ ﻋﺒﺪاﻟﻌﺰﻳﺰ
٤١
آﻠﻴﺔ ﻋﻠﻮم اﻷرض
أد/ ﻋﺒﺎس ﺑﻦ ﻋﻴﻔﺎن اﻟﺤﺎرﺛﻲ
ﻗﺴﻢ اﻟﺠﻴﻮﻟﻮﺟﻴﺎ اﻟﻬﻨﺪﺳﻴﺔ و اﻟﺒﻴﺌﻴﺔ
43. Compaction Characteristics and Soil Grouping in USCS
Group Symbol
Value as
Compaction Compressibility
Embankment
Characteristics and Expansion
Material
GW
Good
Very Little
GP
Good
Very Little
GM
Good
Slight
GC
Good
Slight
SW
Good
Very Little
SP
Good
Very Little
SM
Good
Slight
SC
Good to Fair
Slight to
Medium
ML
Good to Poor
Slight to
Medium
CL
OL, MH, CH,
OH, PT
Good to Fair
Medium
Very Stable
Reasonably
Stable
Reasonably
Stable
Reasonably
Stable
Very Stable
Reasonably
Stable when
Dense
Reasonably
Stable when
Dense
Reasonably
Stable
Poor, gets better
with high
density
Stable
Fair to Poor
High
Poor, Unstable
EEG 341 ﻣﻘﺮر اﻟﺠﻴﻮﻟﻮﺟﻴﺎ اﻟﻬﻨﺪﺳﻴﺔ
ﺟﺎﻣﻌﺔ اﻟﻤﻠﻚ ﻋﺒﺪاﻟﻌﺰﻳﺰ
٤٢
آﻠﻴﺔ ﻋﻠﻮم اﻷرض
Value as
Subgrade
Material
Excellent
Excellent to
Good
Excellent to
Good
Good
Good
Good to Fair
Good to Fair
Good to Fair
Fair to Poor
Fair to Poor
Poor to Not
Suitable
أد/ ﻋﺒﺎس ﺑﻦ ﻋﻴﻔﺎن اﻟﺤﺎرﺛﻲ
ﻗﺴﻢ اﻟﺠﻴﻮﻟﻮﺟﻴﺎ اﻟﻬﻨﺪﺳﻴﺔ و اﻟﺒﻴﺌﻴﺔ
44. 2. Dewatering
When soil is excavated below or near the water table, pumps will usually be used to
dewater the site. This involves creating a drawdown curve (or cone of depression) that is
below the base of the excavation. Factors that are important include soil permeability,
depth of water table, depth (and geometry) of excavation.
Single stage dewatering
The above diagram illustrates a dewatering technique using small trenches dug around
the perimeter of the excavation. One can estimate the pumping requirements based upon
the formula
(reference: Soils In Construction, W.L. Schroeder, S.E. Dickenson, Prentice Hall 1996,
pg. 162). The value D represents the radius of influence, H is the depth to an
impermeable layer from the original water table, ht is the height of the water level in the
interceptor ditch with respect to the impermeable layer, k is the soil’s permeability, and q
is the pump per unit length of ditch. A more elaborate two-stage dewatering technique is
shown in the diagram below.
Multi-stage dewatering
EEG 341 ﻣﻘﺮر اﻟﺠﻴﻮﻟﻮﺟﻴﺎ اﻟﻬﻨﺪﺳﻴﺔ
ﺟﺎﻣﻌﺔ اﻟﻤﻠﻚ ﻋﺒﺪاﻟﻌﺰﻳﺰ
٤٣
آﻠﻴﺔ ﻋﻠﻮم اﻷرض
أد/ ﻋﺒﺎس ﺑﻦ ﻋﻴﻔﺎن اﻟﺤﺎرﺛﻲ
ﻗﺴﻢ اﻟﺠﻴﻮﻟﻮﺟﻴﺎ اﻟﻬﻨﺪﺳﻴﺔ و اﻟﺒﻴﺌﻴﺔ
45. As a general rule, when the excavation is deep (with respect to the water table) and
the soil is very permeable (i.e. gravel or sand), a high pumping rate will be required.
For an excavation that extends just slightly below the water table and the soil is
somewhat impermeable (i.e. clay or silt), a lower pumping rate is required. Be
careful, the depth of a water table varies as a function of time for any given site!
This means that the depth of the water table varies with seasons or possibly local
precipitation.
Drawdown curve for an excavation site with two pumps.
EEG 341 ﻣﻘﺮر اﻟﺠﻴﻮﻟﻮﺟﻴﺎ اﻟﻬﻨﺪﺳﻴﺔ
ﺟﺎﻣﻌﺔ اﻟﻤﻠﻚ ﻋﺒﺪاﻟﻌﺰﻳﺰ
٤٤
آﻠﻴﺔ ﻋﻠﻮم اﻷرض
أد/ ﻋﺒﺎس ﺑﻦ ﻋﻴﻔﺎن اﻟﺤﺎرﺛﻲ
ﻗﺴﻢ اﻟﺠﻴﻮﻟﻮﺟﻴﺎ اﻟﻬﻨﺪﺳﻴﺔ و اﻟﺒﻴﺌﻴﺔ
46. 3. Stress and Settlement
A strange case of Palace of Fine Arts in the Alameda area of Mexico City. Built
sometime between 1900 and 1934, it was a magnificent and strongly built structure.
It was built on grade, level with the square and other buildings nearby. But because
of loose sand permeated with water in the subsurface, the massive structure sunk 6 ft
into the ground! (Luckily, it settled evenly minimizing structural damage.) Believe
it or not, in the 1960’s the building moved again. This time it moved 12 ft up! The
weight of skyscrapers being built around the Palace had pushed the subsurface water
and soil around sufficiently to raise the building.
(Source: Why Buildings Fall Down, M. Levy and M. Salvadori, WW Norton & Company, 1992)
The Milwaukee Metropolitan Sewerage District (MMSD) agreed to a $24 million
settlement in a claim against the engineering firm CH2M Hill. MMSD claimed the
engineering firm mis-judged the weak bedrock and potential for flooding in the
designs of a 5.3-mile North Shore deep tunnel project. This project was designed to
store raw sewage during rain-storms and snow melts, preventing the polluted water
from fouling the area’s rivers and Lake Michigan. MMSD also agreed to pay $3.5
million to settle claims from downtown businesses. These businesses claimed water
pouring into the tunnel drained ground water under downtown businesses, causing
building foundations, walls, sidewalks and sewer connections to crack.
(Source: Milwaukee Journal Sentinel, December 5, 1998)
Worlds oldest building code, the Code of Hammurabi.
Settlement and Consolidation of Soils
Any structure built on soil is subject to settlement. Some settlement is inevitable and,
depending on the situation, some settlements are tolerable. When building structures
on top of soils, one needs to have some knowledge of how settlement occurs and
predict how much and how fast settlement will occur in a given situation.
Important factors that influence settlement:
•
•
•
•
•
Soil Permeability
Soil Drainage
Load to be placed on the soil
History of loads placed upon the soil (normally or over-consolidated?)
Water Table
Settlement is caused both by soil compression and lateral yielding (movement of soil
in the lateral direction) of the soils located under the loaded area. Cohesive soils
usually settle from compression while cohesionless soils often settle from lateral
yielding – however, both factors may play a role. Some other less common causes of
settlement include dynamic forces, changes in the groundwater table, adjacent
excavations, etc. Compressive deformation generally results from a reduction in the
void volume, accompanied by the rearrangement of soil grains. The reduction in void
volume and rearrangement of soil grains is a function of time. How these
EEG 341 ﻣﻘﺮر اﻟﺠﻴﻮﻟﻮﺟﻴﺎ اﻟﻬﻨﺪﺳﻴﺔ
ﺟﺎﻣﻌﺔ اﻟﻤﻠﻚ ﻋﺒﺪاﻟﻌﺰﻳﺰ
٤٥
آﻠﻴﺔ ﻋﻠﻮم اﻷرض
أد/ ﻋﺒﺎس ﺑﻦ ﻋﻴﻔﺎن اﻟﺤﺎرﺛﻲ
ﻗﺴﻢ اﻟﺠﻴﻮﻟﻮﺟﻴﺎ اﻟﻬﻨﺪﺳﻴﺔ و اﻟﺒﻴﺌﻴﺔ
47. deformations develop with time depends on the type of soil and the strength of the
externally applied load (or pressure). In soils of high permeability (e.g. coarse-grained
soils), this process requires a short time interval for completion, and almost all
settlement occurs by the time construction is complete. In low permeable soils (e.g.
fine-grained soils) the process occurs very slowly. Thus, settlement takes place slowly
and continues over a long period of time. In essence, a graph of the void ratio as a
function of time for several different applied loads, provides an enormous amount of
information about the settlement characteristics of a soil.
Terminology
Pressure (or load) is defined as the amount of weight being distributed over an
amount of area. Mathematically:
.
Overburden pressure is the effective pressure (sometimes referred to as effective
weight) of the overlaying soil. This can be calculated according to the formula P=γh
where γ is the unit weight of overlaying soil and h is the depth.
Normally consolidated clay has never been subjected to any loading larger than the
present effective overburden pressure. The height of the soil above the clay has been
fairly constant through time.
Overconsolidated clay has been subjected at some time to a loading greater than the
present overburden pressure. This type of clay is generally less compressible.
Coefficient of consolidation, cv, is a measure of how fast and how much a sample of
soil will deform under a load. A large value indicates a fast consolidation and a low
value indicates a slow consolidation.
Estimating Settlement in Clay and Sand
How fast does the soil settle?
The process of obtaining a quantitative prediction of how much a soil will settle and
how fast begins with examining a plot of soil deformation as a function of time for a
given load. The soil deformation will correspond to a void ratio. Figure 1 shows such
a plot.
Figure 1
Primary consolidation of the soil happens before point A on the graph.
EEG 341 ﻣﻘﺮر اﻟﺠﻴﻮﻟﻮﺟﻴﺎ اﻟﻬﻨﺪﺳﻴﺔ
ﺟﺎﻣﻌﺔ اﻟﻤﻠﻚ ﻋﺒﺪاﻟﻌﺰﻳﺰ
٤٦
آﻠﻴﺔ ﻋﻠﻮم اﻷرض
أد/ ﻋﺒﺎس ﺑﻦ ﻋﻴﻔﺎن اﻟﺤﺎرﺛﻲ
ﻗﺴﻢ اﻟﺠﻴﻮﻟﻮﺟﻴﺎ اﻟﻬﻨﺪﺳﻴﺔ و اﻟﺒﻴﺌﻴﺔ
48. The secondary consolidation happens after point A and is characterized by a very
slow settlement. The coefficient of consolidation, cv, for a particular loading is related
to the shape of this graph and is defined as
(1)
where H is the thickness of the test specimen at 50% consolidation, and t50 is the time
to 50% consolidation. One can use this parameter to calculate the time rate of
settlement with equation 2 and figure 2. The time, t, to reach a particular percent of
consolidation is
(2)
where H is the thickness of the consolidating layer, Tv is a time factor that depends of
the percent consolidation and is obtained from figure 2, and cv is the coefficient of
consolidation.
Figure 2
How much will the soil settle?
Figure 3
EEG 341 ﻣﻘﺮر اﻟﺠﻴﻮﻟﻮﺟﻴﺎ اﻟﻬﻨﺪﺳﻴﺔ
ﺟﺎﻣﻌﺔ اﻟﻤﻠﻚ ﻋﺒﺪاﻟﻌﺰﻳﺰ
٤٧
آﻠﻴﺔ ﻋﻠﻮم اﻷرض
أد/ ﻋﺒﺎس ﺑﻦ ﻋﻴﻔﺎن اﻟﺤﺎرﺛﻲ
ﻗﺴﻢ اﻟﺠﻴﻮﻟﻮﺟﻴﺎ اﻟﻬﻨﺪﺳﻴﺔ و اﻟﺒﻴﺌﻴﺔ
49. Now, to calculate the total settlement due to primary consolidation, we need to
introduce the equation (derived from figure 3):
(3)
where
S = total settlement due to primary consolidation,
eo = initial void ratio of the soil in situ,
e = void ratio of the soil when subjected to a total pressure (p),
H = thickness of the consolidating clay layer (if the cohesive soil layer is underlain by sand
and gravel then use ½H for the thickness and use H if underlain by bedrock) ,
p = total pressure acting at midheight of the consolidating layer,
po = present effective overburden pressure at midheight of the consolidating layer.
The constant Cc is the compression index and is equal to the slope of the curve
indicated in figure 3. Its value can be calculated by
(4)
with the variables defined the same as in equation 3.
Example: Consider an 8 ft clay layer beneath a building that is overlain by a stratum
of permeable sand and gravel and is underlain by impermeable bedrock. The total
expected consolidation settlement for the clay layer due to the footing load is 2.5 in. It
is also known from laboratory tests that cv=2.68x10-3 in.2/min.
Find: (1) How many years it will take for 90% of the total expected consolidation settlement to take
place? (2) What amount of consolidation settlement will occur in 1 yr.?
(2)
(1)
Work part one in reverse:
t = (Tv/cv)H2
Tv = 0.848 (using U = 90% in figure 2)
H = 8ft(12in/1ft) = 96 in
t = (1yr)(365d/1yr)(24hr/1d)(60min/1hr) =
2
2
2
t90 = ( (0.848)(96in) )/(2.68x10 in /min) 5.26x105 min
= 2.9x106 min
Tv = (tcv)/H2 = ( (5.26x105 min)(2.69x10-3
or
in2/min) )/(96in)2 = 0.15
Tv = 0.15 corresponds to U = 43% (figure
2.9x106 min
(1hr/60min)(1d/24hr)(1yr/365d) = 5.5
2)
Thus, S1yr = (2.5in)(0.43) = 1.08 in.
years
In sandy soils, settlement occurs fast (soil is usually settled before construction is
done) and the amount of settlement is determined in a different way than cohesive
soils. The maximum settlement on dry sand can be calculated by
where smax is the maximum settlement (inches), q is the applied pressure (tsf), B is the
width of the footing, and Nlowest is a number of blows required to drive a rod while
following a standard set of procedures. It should be noted that this equation has a
correction factor if the groundwater table is close to the footing.
Example of a settlement analysis with a high water table and multiple soil
layers
EEG 341 ﻣﻘﺮر اﻟﺠﻴﻮﻟﻮﺟﻴﺎ اﻟﻬﻨﺪﺳﻴﺔ
ﺟﺎﻣﻌﺔ اﻟﻤﻠﻚ ﻋﺒﺪاﻟﻌﺰﻳﺰ
٤٨
آﻠﻴﺔ ﻋﻠﻮم اﻷرض
أد/ ﻋﺒﺎس ﺑﻦ ﻋﻴﻔﺎن اﻟﺤﺎرﺛﻲ
ﻗﺴﻢ اﻟﺠﻴﻮﻟﻮﺟﻴﺎ اﻟﻬﻨﺪﺳﻴﺔ و اﻟﺒﻴﺌﻴﺔ
50. Time of Soil Settlement Animation
Illustrates primary and secondary rates of consolidation.
Soil
Compression
Characteristics
Animation
Soil does not behave like a spring (i.e. it does not follow Hooke’s Law). Once
compressed it rebounds only slightly upon un-loading. This animation demonstrates
the different behavior for normally consolidated and over-consolidated soil.
Settlement cracks that have developed in the masonry near
the the Stout physics department offices in Jarvis Hall.
Same crack line but on the opposite side of the wall. The
crack goes right into the floor tiling.
Differential settlement of the Soil Retaining wall at UW-Stout during the summer of
2001.
EEG 341 ﻣﻘﺮر اﻟﺠﻴﻮﻟﻮﺟﻴﺎ اﻟﻬﻨﺪﺳﻴﺔ
ﺟﺎﻣﻌﺔ اﻟﻤﻠﻚ ﻋﺒﺪاﻟﻌﺰﻳﺰ
٤٩
آﻠﻴﺔ ﻋﻠﻮم اﻷرض
أد/ ﻋﺒﺎس ﺑﻦ ﻋﻴﻔﺎن اﻟﺤﺎرﺛﻲ
ﻗﺴﻢ اﻟﺠﻴﻮﻟﻮﺟﻴﺎ اﻟﻬﻨﺪﺳﻴﺔ و اﻟﺒﻴﺌﻴﺔ
51. 4. Foundations
"On account of the fact that there is no glory attached to the foundations
and that the sources of success or failure are hidden deep in the ground,
building foundations have always been treated as step children and their
acts of revenge for the lack of attention can be very embarrassing." Karl
Terzaghi [source: Lundin, T., 2001, Are you saving nickels or dollars?, Hanson
Insight newsletter, <http://www.hansonengineers.com/insight/0502/story4.htm>,
May]
Important aspects to be aware of:
I. In the design plans, the depth of the footings should be indicated with respect to the
final grade around the house. Foundation footings should be no less than 4 feet deep
(Wisconsin Standard) and should not be placed onto disturbed soil. The footings need
to be below the frost line. The frost line is the depth to which soil freezes during the
winter. The soil above the frost line is subject to large amounts of fost heaving and
shrinking (when ice melts) and can cause extreme cracking for too shallow of
foundations.
II. Foundation footings should be placed upon good soil. This information can be
obtained by soil exploration and laboratory testing. One could also ask neighbors
about their foundations and the extent of cracking in their walls.
III. The sewer pipe should enter the house below the footing (sometimes at a depth of
8 inches from the bottom of the footing to the top of the pipe). The sewer pipe should
have a slope of about 1/8in. every foot causing contents to move away from the
house.
Bearing Capacity for Shallow Foundations
Structure foundations are subject not only to settlement but also to shear failures. First
of all, foundations usually have the design of an inverted T. Where columns or walls
are resting on a footing and the footing has an enlarged area to reduce the pressure
exerted on the soil for a given load. In general, foundations must be designed to
satisfy the following criteria:
1. They must be located properly (both vertically and horizontally orientation) so
as not to be adversely affected by outside influences.
2. They must be safe from excessive (or non-uniform) settlement.
3. They must be safe from bearing capacity failure (shear failure).
There are three modes of shear failure: general shear failure, local shear failure, and
punching shear failure. These modes characterize the stress-strain dynamics that
happen in certain soil types.
General shear failure is identified by a well-defined wedge beneath the foundation
and slip surfaces extending diagonally from the side edges of the footing downward
through the soil, then upward to the ground surface. The ground surface adjacent to
the footing bulges upward. Soil displacement is accompanied by tilting of the
foundation (unless the foundation is restrained). The load-settlement curve for the
general shear case indicates that failure is abrupt.
EEG 341 ﻣﻘﺮر اﻟﺠﻴﻮﻟﻮﺟﻴﺎ اﻟﻬﻨﺪﺳﻴﺔ
ﺟﺎﻣﻌﺔ اﻟﻤﻠﻚ ﻋﺒﺪاﻟﻌﺰﻳﺰ
٥٠
آﻠﻴﺔ ﻋﻠﻮم اﻷرض
أد/ ﻋﺒﺎس ﺑﻦ ﻋﻴﻔﺎن اﻟﺤﺎرﺛﻲ
ﻗﺴﻢ اﻟﺠﻴﻮﻟﻮﺟﻴﺎ اﻟﻬﻨﺪﺳﻴﺔ و اﻟﺒﻴﺌﻴﺔ
52. Punching shear failure involves significant compression of a wedge-shaped soil zone
beneath the foundation and is accompanied by the occurrence of vertical shear
beneath the edges of the foundation. The soil zones beyond the edges of the
foundation a little affected, and no significant degree of bulging occurs. Aside from a
large settlement, failure is not clearly recognized.
Local shear failure has elements of both general and punching shear failure. It has
well-defined slip surfaces that fade into the soil mass beyond the edges of the
foundation and do not carry upward to the ground surface. Slight bulging of the
ground surface adjacent to the foundation does occur. Significant vertical
compression takes place beneath the foundation.
EEG 341 ﻣﻘﺮر اﻟﺠﻴﻮﻟﻮﺟﻴﺎ اﻟﻬﻨﺪﺳﻴﺔ
ﺟﺎﻣﻌﺔ اﻟﻤﻠﻚ ﻋﺒﺪاﻟﻌﺰﻳﺰ
٥١
آﻠﻴﺔ ﻋﻠﻮم اﻷرض
أد/ ﻋﺒﺎس ﺑﻦ ﻋﻴﻔﺎن اﻟﺤﺎرﺛﻲ
ﻗﺴﻢ اﻟﺠﻴﻮﻟﻮﺟﻴﺎ اﻟﻬﻨﺪﺳﻴﺔ و اﻟﺒﻴﺌﻴﺔ
