Transcript Slide 1

Lumpy fill in land reclamation
Dr. R. G. Robinson
Department of Civil Engineering
IIT Madras, India
Prof. Tan Thiam Soon
Dr. Ganeswara Rao Dasari
Contents of Presentation
Overview
 Coastal Reclamation
 Lumpy fill
 Laboratory studies on lumpy fill
 Field Tests
 Conclusions

Contents of Presentation
 Overview
Coastal reclamation
 Lumpy fill
 Laboratory studies on lumpy fill
 Field tests
 Conclusions

Original land area : 580 km2
Population: 4 million
Expected to increase to 5.5 million
in 40-50 years
Contents of Presentation

Overview
 Coastal
reclamation
Lumpy fill
 Laboratory studies on lumpy fill
 Field tests
 Conclusions

Stages of Reclamation
Stage I- Planning
Identify the area to be reclaimed. (HDB, JTC and
PSA are the major agencies).
Stage II-Environmental Impact Assessment
 Tidal
flow patterns, water level, sedimentation
and water quality.
 Impact on sea life.
 Erosion of main land and silting of ports.
 Convince and get approval from Parliament.
….. Stages of Reclamation

Stage III- Construction of sand bunds along the
perimeter to contain the fill

Stage IV-Placing of fill within the sand bund
Sand
 Clay

•
•

Hydraulic fill
Lumpy fill
Stage V-Soil stabilization
Dynamic compaction if it is sand fill
 Surcharge if it is clay

Land Area
2
Land area (km )
720
680
640
600
560
1940 1960 1980 2000 2020
Year
Population density (person/km 2)
760
Population density
6000
5000
4000
3000
2000
1960
1980
2000
Year
2020
Land Reclamation in Singapore-Growing city state
Punggol
Kranji
Tekong/
Ubin
Changi Airport
Jurong Island
Reclaimed area=31%
Marina Bay
Tuas
Pasir Panjang Port
Sentosa
Southern Islands
Strait Times (2000)
Land Reclamation in Singapore-Some major projects
Year
Site
Area (ha)
Vol. of
sand, Mm3
1974-1979
Changi airport
750
40
1983-1986
Changi north
181
12
1985-1989
Tuas
637
69
1981-1985
Pulau Tekong Besar
510
28
1992-2005
Changi East
2086
272
Reclamation
depth
increasing
In-land
materials
depleted
Increasing
Underground
Constructions
Maintenance
of Navigation
Channels
High cost of
imported
sand
Lack of
disposal
ground
HYDRAULIC FILL- Clay slurry
Contains
mainly slurry with occasional
occurrence of small lumps suspended in
slurry
Apply
surcharge to consolidate
Double
handling
Cannot
handle unwanted soil directly
Layered sand-clay scheme (Karunaratne et al. 1990)
Changi south bay
Clay slurry

40 ha (1988) Trial project

Clay slurry  200% water content
Clay slurry
after 1 week
Clay slurry
Sand cap can be formed for dosage
Seabed

< 15 cm

Careful construction control crucial
to prevent sand loss

Sand placement rather time-
consuming

Cannot handle waste soils directly
Contents of Presentation
Overview
 Coastal reclamation

 Lumpy
fill
Laboratory studies on lumpy fill
 Field tests
 Conclusions

CLAY LUMPS
Produced by underground construction & seabed
dredging
 Volume of lumps can easily exceed 1 m3
 Waste soil (unwanted soil) can be handled directly

1.0m
Clamb-shell grab
Dredging of seabed
Lumps placed in a barge
Lumpy Fill
- Place the material in the form of lumps,
directly at the reclamation site
Clamshell grab
Dredging of seabed
Clay lumps placed in a barge
Dumping of clay lumps by bottom-open barge
Barge size:
Width: ~10 m
Length: ~20 m
Depth : ~5 m
Volume: 900-1000 m3
Typical Land Reclamation Scheme
Mean sea level
Sand surcharge
Clay lumps
Inter-lump voids
Filled water
Seabed
Some aspects….

Consolidation behaviour

Closing of inter-lump voids

Shear strength of the fill after stabilization

Creep/Secondary compression


Influence of clay slurry in the inter-lump voids
Effect of degree of swelling
Contents of Presentation
Overview
 Coastal reclamation
 Lumpy fill

 Laboratory
Field tests
 Conclusions

studies on lumpy fill
Typical seabed profile
0
0
Corrected cone resistance, qt (MPa)
4
12
Upper marine clay
~8200 years
Forms lumps
~24000 years
10
After dredging
Forms slurry
Surface soft marine clay
5
Depth below seabed (m)
8
May or may not
form lumps
Intermediate layer
15
20
Pore pressure
Cone resistance
25
Lower marine clay
Forms lumps
~28000 years
30
Weathered rock
35
0
0.4
0.8
1.2
1.6
Pore pressure, u2 (MPa)
2
Soil used for the study
1.5 m
Depth : 13m
LL=77%
PL=36%
PI=41%
Sand=5%
Silt size=55%
Clay=40%
NMC=60%
One-dimensional consolidation tests
Typical time-settlement curve
Time, min
0.1
1
10
0
Settlement, mm
0.2
0.4
0.6
0.8
1
1.2
1.4
1.6
1.8
Cv=1.25 x 10-3 cm2/s
H = 19 mm
Double drainage
100
e-log sv’ curves from conventional oedometer tests on
homogeneous clay
2.5
Undisturbed
ICL
Void ratio, e
2.0
s’c=200 kPa
OCR= 2.5
1.5
1.0
1
10
100
Consolidation pressure, kPa
1000
Tests on lumpy fill
Preparation of clay lumps
Cut using wire cutter
25 mm cubical lumps
Experimental set-up
LVDT
Burette
Loading frame
Perforated loading cap
Geotextile filter
Clay lumps
Geotextile filter
Sand drain
Experimental Programme
1. Effect of packing (using 25 mm lumps)
1.
2.
Placed directly in water-Test 1
Packed in the container and then added
water
(Test 2 and Test 3)
2. Effect of size
12.5, 25, 50 mm cubical lumps
3. Effect of degree of swelling



Degree of swelling =0%
50% and
100%
State of the fill under different consolidation pressures in Test 1
100 mm
0 kPa
27 kPa
10 kPa
50 kPa
Effect of initial packing on e-logs’v curves
3.5
Test 1 (eiv=1.05, e=4.31
Test 2 (eiv=0.93, e=3.99)
3
Test 3 (eiv=0.57, e=3.07
Undisturbed
Void ratio, e
ICL
2.5
25 mm cubical lumps
2
1.5
1
1
10
100
Consolidation pressure, kPa
1000
Effect of size on e-logs’v curves
Void ratio, e
3.5
3
12.5 mm
25mm
50 mm
2.5
eiv = 0.60±0.03
2
1.5
1
1
10
100
Consolidation pressure, kPa
1000
Typical time-settlement curves
Time, s
1
10
100
1000
10000
100000
1000000
0
Test 1
Normalized settlement
0.2
0.4
100-200 kPa
16-27 kPa
0.6
27-50 kPa
200-400 kPa
0.8
50-100 kPa
1
Pore pressure inside and in between the lumps
30
120
Dsv=25 kPa
Dsv=100 kPa
100
Inside the lump
20
Pore pressure, kPa
Pore pressure, kPa
25
15
In between the lumps
10
Inside the lump
80
In between the lumps
60
40
20
5
100-200 kPa
25-50 kPa
0
0
1
1
10
100
1000
Time, s
10000 100000
10
100
1000
Time, s
10000
100000 1000000
Typical e-log sv’ curves of lumpy fill
Lump size : 25 mm
No. of lumps: 90
Fill height: 170 mm
3.5
Lumpy fill
Undisturbed
ICL
Void ratio, e
3.0
2.5
s’c=200 kPa
2.0
e0 = 1.59
1.5
1.0
1
10
100
Consolidation pressure, kPa
1000
Permeability of lumpy fill system
Lump size : 25 mm
No. of lumps: 90
Fill height: 170 mm
Coefficient of permeability, m/s
1.E-04
Lumpy fill
Undisturbed
1.E-05
ICL
1.E-06
1.E-07
1.E-08
1.E-09
1.E-10
1.E-11
1
10
100
Consolidation pressure, kPa
1000
Cone penetration test on lumpy fill
The Cone
Lump size : 50 mm
Penetration rate: 5mm/s
10 mm
qc  s vo
su 
Nk
su
svo
Nk
3 mm
Load Cell
30 mm
Nk =
Undrained shear strength
Overburden pressure
Cone factor
9.5 against vane shear
CPT were conducted under
sv’=50, 100, 200 and 360 kPa
Thanks to Hokuto Ricken Co., Japan
Shear strength profile under 50 kPa
su, kPa
0
10
20
0
20
Depth, mm
40
su=0.23sv' (OCR)0.75
60
80
100
120
140
su=0.23 sv'
30
40
50
Shear strength profile under 100 kPa
su, kPa
0
10
20
30
0
20
Depth, mm
40
0.75
su=0.23sv' (OCR)
60
80
100
120
140
su=0.23 sv'
40
50
Shear strength profile under 200 kPa
su, kPa
0
10
20
30
0
20
Depth, mm
40
60
80
100
120
140
su=0.23 sv'
40
50
Shear strength profile under 360 kPa
su, kPa
0
20
40
60
0
20
Depth, mm
40
60
80
100
120
140
su=0.23 sv'
80
100
Secondary compression of lumpy fill
Coeff. of Secondary Compression
4
Mesri’s (C/Cc ) concept
0.07
Undisturbed
ICL
12.5 mm
0.06
25 mm
3
(C /Cc) = 0.05
50 mm
(C /Cc)
C (%)
0.05
2
0.04
0.03
1
(C /Cc) = 0.03
0.02
0
0.01
10
100
Average consolidation pressure, kPa
1000
10
100
Average consolidation pressure, kPa
1000
Influence of clay slurry
Inter-lump voids filled with water
Inter-lump voids filled with slurry
Lump
Water
Lump
Clay slurry
Lump
Experimental set-up
LVDT
Burette
Loading frame
Perforated loading cap
Geotextile filter
Clay lumps
Geotextile filter
Sand drain
Typical time-compression curves
Settlement, mm
0
ILV with slurry
(w=150%)
4
ILV with slurry
(w=300%)
8
ILV with water
12
(a) 6-12 kPa
16
1
100
10000
Time,s
1000000
…….Typical time-compression curves……….
Settlement, mm
0
ILV with slurry
(w=150%)
4
ILV with water
ILV with slurry(w=300%)
8
(b) 50-100 kPa
12
1
100
10000
Time, s
1000000
…….Typical time-compression curves
Settlement, mm
0
ILV with slurry
(w=150%)
4
ILV with water
ILV with slurry(w=300%)
8
(c) 200-400 kPa
12
1
100
10000
Time, s
1000000
Applicability of Terzaghi’s theory
Time factor (Tv)
Degree of consolidation (%)
0.0001
0
0.001
0.01
20
40
60
80
100
Terzaghi's Theory
6-12 kPa (150%)
12-25 kPa (150%)
6-12 kPa (300%)
12-25 kPa (300%)
0.1
1
10
e-log s’v curves
3
Undisturbed
ICL
ILV with water
Void ratio, e
2.5
ILV with slurry (w=150%)
2
ILV with water (w=300%)
1.5
1
0.5
1
10
100
Consolidation pressure, kPa
1000
Variation of permeability with consolidation pressure
10-4
Undisturbed
Coefficient of permeability, m/s
ICL
10-5
ILV filled with water
ILV filled with slurry (w=150%)
10-6
10-7
10-8
10-9
10-10
10-11
1
10
100
Consolidation pressure, kPa
1000
Pore pressure inside and in between the lumps
Inter-lump voids with water
Inter-lump voids filled with slurry
30
30
Dsv=25 kPa
Inside the lump
20
15
In between the lumps
10
5
Dsv=25 kPa
25
Pore pressure, kPa
Pore pressure, kPa
25
20
Inside the lump
15
In between the lumps
10
5
25-50 kPa
25-50 kPa
0
0
1
10
100
1000
Time, s
10000 100000
1
10
100
1000
Time, s
10000
100000 1000000
Pore pressure inside and in between the lumps
Inter-lump voids with water
Inter-lump voids filled with slurry
120
120
Dsv=100 kPa
Inside the lump
80
In between the lumps
60
40
20
Dsv=100 kPa
100
Pore pressure, kPa
Pore pressure, kPa
100
80
60
40
100-200 kPa
20
100-200 kPa
0
0
1
10
100
1000
Time, s
10000
100000 1000000
1
10
100
1000
Time, s
10000
100000 1000000
Influence of swelling of lumps
Lumps in the field are very large and may not reach fully swollen state
if sufficient time is not allowed before the application of surcharge
Swelling test
To find the time required for different degrees of
swelling
Degree of Swelling, Us
Us
 w  wi 
 100
w
f

w
i


Us  
w = moisture content of the specimens after
immersing in water at any instant of time
wi = initial moisture content of the specimen
wf = moisture content of the fully swollen specimen
For a cubical lump of 25 mm, t50=20 min
Time
State of the lumpy fill under sv’ = 50 kPa (25 mm lumps)
Us = 0%
Us=50%
Us=100%
Swelling of clay lumps
THREE DIMENSIONAL SWELLING OF CLAY LUMPS
Method I
 Obtain the water content of the lump with time
during swelling.
 Suitable for small size lumps only
Method II
 Obtain the volume change with time during swelling
 Not simple for three-dimensional swelling
Method III
Obtain the pore-pressure dissipation with time
Simple and easy to make the measurements
Three dimensional swelling of clay lumps
Soils used
Instrument used
Kaolinite:
LL=82%, PL=40%
28 mm
Cylindrical samples of
105, 205 and 400 mm
6 mm diameter
12 mm
Marine clay:
LL=56%, PL=33%
Cylindrical samples of
105 and 205 mm
Tensiometer
PPT
Performance of PPT in comparison with Tensiometer during desiccation
100
PPT
Tensiometer
60
240 mm
Suction, kPa
80
40
T
PPT
240 mm
20
0
0
5000
10000
Time, min
15000
20000
EXPERIMENTAL PROCEDURE
Load
Split mould
Water
Lump
Outer container
Filter
Schematic of the split mould for conducting swelling test
160
Split
m ould
Clay
Slurry
7
8
750
160
Oute r containe r
4
5
6
160
Pore pre s s ure
trans duce rs
400PPT-1
2
160
550
3
Ge ote xtile
50
400
650
(All dimensions are in mm)
Bottom s and
drain
View of the split mould for conducting swelling test
Pneumatic piston
Split mould
Outer container
View of the kaolinite lump of 400 mm diameter
after removing the split mould
400 mm
Dissipation of suction on submerging the kaolinite lump
of 400 mm diameter in water
1.2
400PPT-3
400PPT-5
400PPT-6
0.8
97.5
0.6
97.5
0.4
7
8
400PPT-3 4 5 6
50 m m
195
Normalized suction (u/u0)
1
0.2
Clay lump
0
1
10
100
1000
Time, s
10000
100000
Normalized suction at the centre of marine clay lumps
1.4
105 mm
Normalized suction (u/uo )
1.2
205 mm
1
0.8
0.6
0.4
0.2
0
1
10
100
1000
Time, s
10000
100000
1000000
Initial state
End state
Kaolinite
Marine clay
Variation of water content within the marine clay lump of
205 mm diameter after full swelling
wl
wo
Water content (%)
42
0
Depth, cm
4
8
12
16
20
44
46
48
50
52
54
56
Water content variation within the lump-Undisturbed
Cube : 50 mm
80
Water content (%)
wL
wo
75
70
65
60
-30
-20
-10
0
10
20
Distance from centre of lump, mm
30
Finite Element Analysis
Finite Element Analysis
Finite Element mesh
Soil Parameters
Property
Kaolinite
Marine clay
f’o
25
23
Ko
0.58
0.61
n
0.3
0.3
E in kPa
3000
4000
k
0.05
0.03
kv in m/s e=1.21log(kv)+11.2 e=0.912 log(kv)+9.8
kh/kv
1.9
2.3
Effect of soil model (Kaolinite lump 105 mm diameter)
Acknowledgement: Dr. Ganeswara Rao Dasari
(1) Linear Elastic
1.2
(2) Non-linear Elastic (NLE1)
NLE1
K'
(1  e) p '
k
(3) Non-linear Elastic (NLE2)
k = 0.005 +0.10 log (OCR)
(4) NLE2
-Permeability increased
Normalized pore pressure
1
NLE2
0.8
0.6
LE
0.4
(4)
0.2
0
1
10
100
Time, s
1000
10000
Predicted and measured suctions at the centre of marine clay lumps
1.4
Normalized suction (u/uo)
1.2
NLE2 (205 mm diameter)
1
NLE2 (105 mm diameter)
0.8
0.6
0.4
Measured (105 mm diameter)
0.2
Measured (205 mm diameter)
0
1
10
100
1000
Time, s
10000
100000
1000000
Big Tank Experiment
I-section
152x152x37
Base for fixing
hydraulic jack
I-section
457x152x67
3500
1000
2280
1.4m
1500
1.5m
1" thick plate
305
I-section
305x165x46
Stif f ner
SAMPLE PREPARATION
DREDGED & PLACED IN A FLAT BARGE
CUT TO CUBICAL LUMPS OF 150 MM
PACKED IN BAGS & TRANSPORTED TO THE LAB
STORED IN CONTAINERS AFTER COVERING
WITH CLING-FILM
Size of lumps
No. of lumps
No. of layers
Total weight
Height of fill
:
:
:
:
:
15 cm
223
6
1.37t
93 cm
Contents of Presentation
Overview
 Coastal reclamation
 Lumpy fill
 Laboratory studies on lumpy fill

 Field

tests
Conclusions
NUCLEAR DENSITY CONE ND-CPT

Density is related to scattering
of gamma ray

Cesium source Cs137 with half
life of 37.6 years

Housed in standard CPT:
 Diameter = 35.6 mm
 Cone angle = 60
 Cone area = 10 cm2
 Penetration = 1.5 cm/sec
30 cm
Diameter
Calibration Curve
Density Count Ratio (Rp) = [RI Count – BG Count ] / Standard Count
LUMPY FILL TEST SITE AT PULAU PUNGGOL TIMOR

Reclaimed  14 years ago

8 m dredged fill &

10 m sand fill
Test Plan
90
89
91
BH 11
9
8
3.0
68
69
67
2.5

Very dense grid:
 79 ND-CPT
 5 CPTS
 11 Boreholes

4
2.0
87
88
43
19
20
58
54
18
BH 3
1.0
46
22 m
0.5
12
34
BH 8
BH 2
42
3
17
33
21
7
5
66
1.5
70
BH 10
1
44
45
BH 7
30
11
2
0.5
71
86
22m
55
56
57
Spacing 0.5 m at
centre to 6 m at
periphery
59
22
47
13
14
23
BH 5
48
24
37
29
10
28
16
BH 1
53
41
65
6
15
27
38
52
BH 9
25
64
26
76
49
50
51
BH 6
85
61
62
78
77
63
Legend
73
74
84
75
ND-CPT
0.5
PCPT
BH 4
Boreholes
0.5
83
82
81
80
25.5m
25.5 m
All dimensions are in metres
79
Final density of lumpy fill
3
14
Wet Density (kN/m )
16
18
20
22
14
RI 21
BH8- Direct
measurement
Depth (m)
15
16
17
18
BH8-from
water content
Final shear strength of lumpy fill
0
Cone Penetration Test
UU Test
Undrained Shear Strength, (kPa)
Undrained shear strength (kPa)
40
80
120
160
200
30
14
0.23sv '
15
Depth (m)
15
Depth (m)
70
90
14
0.23 s’v
16
50
16
17
17
18
18
BH 1
BH 2
BH 3
BH 4
BH 6
Oedometer test results
Preconsolidation Pressure (kPa)
100
200
300
14
sv'
Depth (m)
15
400
BH 1
BH 2
BH 3
BH 4
BH 5
BH 6
16
OCR=2
17
18
OCR=1
Contents of Presentation
Overview
 Coastal reclamation
 Lumpy fill
 Laboratory studies on lumpy fill
 Field tests

 Conclusions
SOME ISSUES

Time-settlement of lumpy fill
•
•
•

Double porous
Heterogeneous initial condition
Pore pressure generation and dissipation
Swelling of clay lumps
•
•
Time-swell
End state
Acknowledgements
NSTB and HDB for funding
Toa Corporation
Kiso-Jiban
: Contractors for reclamation
: Contractors for in-situ Testing
Researchers:
Mr. M. Karthikeyan
Mr. Yang Li-Ang
Mr. A Vijayakumar
Ms. Goh Wen Jean
Ms. Lim Chea Rong
Ms. Lim Hsiao Chern
Mr. Lim Chee Kiong
Research Engineer
Research Engineer
Research Scholar
FYP
FYP
FYP
FYP
Had Useful discussions with:
Dr. D. W. Hight
Geotechnical Consulting Group, London, UK
Prof. J. Locat
Laval University, Canada
Dr. H. TanakaPort and Airport Research Institute, Japan
Prof. M. Mimura
Kyoto University, Japan
Mr. M. Nobuyama
Soil and Rock Engg. Co. Ltd., Japan
Prof. J .Takemura
Tokyo Institute of Technology, Japan
Thank you