Dr. R. G. Robinson

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Lumpy fill in land reclamation
Dr. R. G. Robinson Department of Civil
Engineering IIT Madras, India
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Prof. Tan Thiam Soon
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Dr. Ganeswara Rao Dasari
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Contents of Presentation

• Overview
• Coastal Reclamation
• Lumpy fill
• Laboratory studies on lumpy fill
• Field Tests
• Conclusions

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Contents of Presentation

• Overview
• Coastal reclamation
• Lumpy fill
• Laboratory studies on lumpy fill
• Field tests
• Conclusions

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Contents of Presentation

• Overview
• Coastal reclamation
• Lumpy fill
• Laboratory studies on lumpy fill
• Field tests
• Conclusions

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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.

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.. 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

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Land Area
Population density
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Land Reclamation in Singapore-Growing city state
Strait Times (2000)
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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
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Use the Unwanted Soil as Fill Material
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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

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Changi south bay
Layered sand-clay scheme (Karunaratne et al. 1990)
Clay slurry

• 40 ha (1988) Trial project
• Clay slurry ? 200 water content after 1 week
• Sand cap can be formed for dosage lt 15 cm
• Careful construction control crucial to prevent
  sand loss
• Sand placement rather time-consuming
• Cannot handle waste soils directly

Clay slurry
Clay slurry
Seabed
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Contents of Presentation

• Overview
• Coastal reclamation
• Lumpy fill
• Laboratory studies on lumpy fill
• Field tests
• Conclusions

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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
Lumps placed in a barge
Dredging of seabed
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Lumpy Fill
- Place the material in the form of lumps,
directly at the reclamation site
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Clay lumps placed in a barge
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Dumping of clay lumps by bottom-open barge
Barge size Width 10 m Length 20 m Depth 5
m Volume 900-1000 m3
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Typical Land Reclamation Scheme
Seabed
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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

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Contents of Presentation

• Overview
• Coastal reclamation
• Lumpy fill
• Laboratory studies on lumpy fill
• Field tests
• Conclusions

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Typical seabed profile
After dredging
Forms slurry
8200 years
Forms lumps
24000 years
May or may not form lumps
Forms lumps
28000 years
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Soil used for the study
Depth 13m LL77 PL36 PI41 Sand5 Silt
size55 Clay40 NMC60
1.5 m
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One-dimensional consolidation tests
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Typical time-settlement curve
Time, min
0.1
1
10
100
0
Cv1.25 x 10-3 cm2/s H 19 mm Double drainage
0.2
0.4
0.6
0.8
Settlement, mm
1
1.2
1.4
1.6
1.8
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e-log sv curves from conventional oedometer
tests on homogeneous clay
sc200 kPa OCR 2.5
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Tests on lumpy fill
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Preparation of clay lumps
Cut using wire cutter
25 mm cubical lumps
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Experimental set-up
LVDT
Burette
Loading frame
Perforated loading cap
Geotextile filter
Clay lumps
Geotextile filter
Sand drain
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Experimental Programme

• 1. Effect of packing (using 25 mm lumps)
• 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

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State of the fill under different consolidation
pressures in Test 1
100 mm
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Effect of initial packing on e-logsv curves
25 mm cubical lumps
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Effect of size on e-logsv curves
eiv 0.600.03
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Typical time-settlement curves
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Pore pressure inside and in between the lumps
Inside the lump
In between the lumps
25-50 kPa
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Typical e-log sv curves of lumpy fill
Lump size 25 mm No. of lumps 90 Fill height
170 mm
sc200 kPa
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Permeability of lumpy fill system
Lump size 25 mm No. of lumps 90 Fill height
170 mm
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Cone penetration test on lumpy fill
The Cone
Lump size 50 mm Penetration rate 5mm/s
10 mm
su Undrained shear strength svo Overburden
pressure Nk Cone factor
Nk 9.5 against vane shear
CPT were conducted under sv50, 100, 200 and
360 kPa
3 mm
30 mm
Load Cell
Thanks to Hokuto Ricken Co., Japan
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Shear strength profile under 50 kPa
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Shear strength profile under 100 kPa
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Shear strength profile under 200 kPa
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Shear strength profile under 360 kPa
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Secondary compression of lumpy fill
Coeff. of Secondary Compression
Mesris (Ca/Cc ) concept
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Influence of clay slurry
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Inter-lump voids filled with water
Inter-lump voids filled with slurry
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Experimental set-up
LVDT
Burette
Loading frame
Perforated loading cap
Geotextile filter
Clay lumps
Geotextile filter
Sand drain
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Typical time-compression curves
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.Typical time-compression curves.
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.Typical time-compression curves
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Applicability of Terzaghis theory
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e-log sv curves
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Variation of permeability with consolidation
pressure
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Pore pressure inside and in between the lumps
Inter-lump voids with water
Inter-lump voids filled with slurry
Dsv25 kPa
Inside the lump
Inside the lump
In between the lumps
In between the lumps
25-50 kPa
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Pore pressure inside and in between the lumps
Inter-lump voids with water
Inter-lump voids filled with slurry
Dsv100 kPa
Dsv100 kPa
Inside the lump
In between the lumps
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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
• 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

Us
Time
For a cubical lump of 25 mm, t5020 min
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State of the lumpy fill under sv 50 kPa (25 mm
lumps)
Us 0
Us50
Us100
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Swelling of clay lumps
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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

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Three dimensional swelling of clay lumps
Soils used Kaolinite LL82,
PL40 Cylindrical samples of 105, 205 and 400
mm Marine clay LL56, PL33 Cylindrical
samples of 105 and 205 mm
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Performance of PPT in comparison with Tensiometer
during desiccation
240 mm
T
PPT
240 mm
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EXPERIMENTAL PROCEDURE
Lump
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Schematic of the split mould for conducting
swelling test
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View of the split mould for conducting swelling
test
Pneumatic piston
Split mould
Outer container
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View of the kaolinite lump of 400 mm diameter
after removing the split mould
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Dissipation of suction on submerging the
kaolinite lump of 400 mm diameter in water
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Normalized suction at the centre of marine clay
lumps
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Initial state
End state
Kaolinite
Marine clay
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Variation of water content within the marine clay
lump of 205 mm diameter after full swelling
wl
wo
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Water content variation within the
lump-Undisturbed
Cube 50 mm
wL
wo
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Finite Element Analysis
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Finite Element Analysis
Finite Element mesh
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Soil Parameters
Property Kaolinite Marine clay
fo 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 e1.21log(kv)11.2 e0.912 log(kv)9.8
kh/kv 1.9 2.3
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Effect of soil model (Kaolinite lump 105 mm
diameter)
Acknowledgement Dr. Ganeswara Rao Dasari
(1) Linear Elastic
(3) Non-linear Elastic (NLE2) k 0.005
0.10 log (OCR)
(4) NLE2 -Permeability increased
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Predicted and measured suctions at the centre of
marine clay lumps
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Big Tank Experiment
1.4m
1.5m
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SAMPLE PREPARATION
DREDGED PLACED IN A FLAT BARGE
PACKED IN BAGS TRANSPORTED TO THE LAB
STORED IN CONTAINERS AFTER COVERING WITH
CLING-FILM
CUT TO CUBICAL LUMPS OF 150 MM
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Size of lumps 15 cm No. of lumps 223 No. of
layers 6 Total weight 1.37t Height of
fill 93 cm
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Contents of Presentation

• Overview
• Coastal reclamation
• Lumpy fill
• Laboratory studies on lumpy fill
• Field tests
• Conclusions

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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

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Calibration Curve
Density Count Ratio (Rp) RI Count BG Count
/ Standard Count
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LUMPY FILL TEST SITE AT PULAU PUNGGOL TIMOR

• Reclaimed ? 14 years ago
• 8 m dredged fill
• 10 m sand fill

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Test Plan

• Very dense grid
• 79 ND-CPT
• 5 CPTS
• 11 Boreholes
• Spacing 0.5 m at centre to 6 m at periphery

22 m
25.5 m
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Final density of lumpy fill
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Final shear strength of lumpy fill
Cone Penetration Test
UU Test
0.23 sv
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Oedometer test results
OCR2
OCR1
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Contents of Presentation

• Overview
• Coastal reclamation
• Lumpy fill
• Laboratory studies on lumpy fill
• Field tests
• Conclusions

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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

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Acknowledgements NSTB and HDB for funding Toa
Corporation Contractors for reclamation Kiso-Jib
an Contractors for in-situ Testing Researchers
Mr. M. Karthikeyan Research Engineer Mr.
Yang Li-Ang Research Engineer Mr. A
Vijayakumar Research Scholar Ms. Goh Wen
Jean FYP Ms. Lim Chea Rong FYP Ms. Lim Hsiao
Chern FYP Mr. Lim Chee Kiong FYP
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Had Useful discussions with Dr. D. W.
Hight Geotechnical Consulting Group, London,
UK Prof. J. Locat Laval University, Canada Dr.
H. Tanaka Port 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
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Thank you