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Dr. R. G. Robinson Department of Civil Engineering IIT Madras, India Lumpy fill in land reclamation.

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Presentation on theme: "Dr. R. G. Robinson Department of Civil Engineering IIT Madras, India Lumpy fill in land reclamation."— Presentation transcript:

1 Dr. R. G. Robinson Department of Civil Engineering IIT Madras, India Lumpy fill in land reclamation

2 Prof. Tan Thiam Soon

3 Dr. Ganeswara Rao Dasari

4 Contents of Presentation  Overview  Coastal Reclamation  Lumpy fill  Laboratory studies on lumpy fill  Field Tests  Conclusions

5  Overview  Coastal reclamation  Lumpy fill  Laboratory studies on lumpy fill  Field tests  Conclusions Contents of Presentation

6 Original land area : 580 km 2 Population: 4 million Expected to increase to 5.5 million in years

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8  Overview  Coastal reclamation  Lumpy fill  Laboratory studies on lumpy fill  Field tests  Conclusions Contents of Presentation

9 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.

10  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 Hydraulic fill Lumpy fill Lumpy fill  Stage V-Soil stabilization  Dynamic compaction if it is sand fill  Surcharge if it is clay ….. Stages of Reclamation

11 Land Area Population density

12 Land Reclamation in Singapore-Growing city state Southern Islands Sentosa Pasir Panjang Port Tuas Jurong Island Punggol Marina Bay Tekong/ Ubin Changi Airport Reclaimed area=31% Kranji Strait Times (2000)

13 Land Reclamation in Singapore-Some major projects YearSite Area (ha) Vol. of sand, Mm Changi airport Changi north Tuas Pulau Tekong Besar Changi East

14 Reclamation depth increasing In-land materials depleted High cost of imported sand Increasing Underground Constructions Maintenance of Navigation Channels Lack of disposal ground

15 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

16  40 ha (1988) Trial project  Clay slurry  200% water content after 1 week  Sand cap can be formed for dosage < 15 cm  Careful construction control crucial to prevent sand loss  Sand placement rather time- consuming  Cannot handle waste soils directly Changi south bay Layered sand-clay scheme (Karunaratne et al. 1990) Seabed Clay slurry

17  Overview  Coastal reclamation  Lumpy fill  Laboratory studies on lumpy fill  Field tests  Conclusions Contents of Presentation

18 CLAY LUMPS  Produced by underground construction & seabed dredging  Volume of lumps can easily exceed 1 m 3  Waste soil (unwanted soil) can be handled directly Dredging of seabed Lumps placed in a barge 1.0m Clamb-shell grab

19 Lumpy Fill Dredging of seabed Clamshell grab - Place the material in the form of lumps, directly at the reclamation site

20 Clay lumps placed in a barge

21 Dumping of clay lumps by bottom-open barge Barge size: Width: ~10 m Length: ~20 m Depth : ~5 m Volume: m 3

22 Seabed Sand surcharge Clay lumps Inter-lump voids Filled water Mean sea level Typical Land Reclamation Scheme

23 Some aspects…. Consolidation behaviour Consolidation behaviour Closing of inter-lump voids Closing of inter-lump voids Shear strength of the fill after stabilization Shear strength of the fill after stabilization Creep/Secondary compression Creep/Secondary compression Influence of clay slurry in the inter-lump voids Influence of clay slurry in the inter-lump voids Effect of degree of swelling Effect of degree of swelling

24  Overview  Coastal reclamation  Lumpy fill  Laboratory studies on lumpy fill  Field tests  Conclusions Contents of Presentation

25 Typical seabed profile ~8200 years ~24000 years ~28000 years Forms slurry Forms lumps May or may not form lumps After dredging

26 Soil used for the study Depth : 13m LL=77% PL=36% PI=41% Sand=5% Silt size=55% Clay=40% NMC=60% 1.5 m

27 One-dimensional consolidation tests

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40 Time, min Settlement, mm C v =1.25 x cm 2 /s H = 19 mm Double drainage Typical time-settlement curve

41 e-log  v ’ curves from conventional oedometer tests on homogeneous clay  ’ c =200 kPa OCR= 2.5

42 Tests on lumpy fill

43 Preparation of clay lumps Cut using wire cutter 25 mm cubical lumps

44 LVDT Burette Loading frame Perforated loading cap Geotextile filter Clay lumps Sand drain Experimental set-up

45 1. Effect of packing (using 25 mm lumps) 1. Placed directly in water-Test 1 2. 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% Experimental Programme

46 0 kPa 10 kPa 50 kPa 27 kPa State of the fill under different consolidation pressures in Test mm

47 Effect of initial packing on e-log  ’ v curves 25 mm cubical lumps

48 Effect of size on e-log  ’ v curves e iv = 0.60±0.03

49 Typical time-settlement curves

50  v =25 kPa Pore pressure inside and in between the lumps Inside the lump In between the lumps kPa Inside the lump In between the lumps  v =100 kPa

51 Typical e-log  v ’ curves of lumpy fill  ’ c =200 kPa Lump size : 25 mm No. of lumps: 90 Fill height: 170 mm

52 Permeability of lumpy fill system Lump size : 25 mm No. of lumps: 90 Fill height: 170 mm

53 Cone penetration test on lumpy fill Lump size : 50 mm Penetration rate: 5mm/s The Cone 3 mm 30 mm 10 mm s u Undrained shear strength  vo Overburden pressure N k Cone factor N k =9.5 against vane shear CPT were conducted under  v ’=50, 100, 200 and 360 kPa Load Cell Thanks to Hokuto Ricken Co., Japan

54 Shear strength profile under 50 kPa

55 Shear strength profile under 100 kPa

56 Shear strength profile under 200 kPa

57 Shear strength profile under 360 kPa

58 Secondary compression of lumpy fill Coeff. of Secondary Compression Mesri’s (C  /C c ) concept

59 Influence of clay slurry

60 Lump Water Lump Clay slurry Lump Inter-lump voids filled with water Inter-lump voids filled with slurry

61 LVDT Burette Loading frame Perforated loading cap Geotextile filter Clay lumps Sand drain Experimental set-up

62 Typical time-compression curves

63 …….Typical time-compression curves……….

64 …….Typical time-compression curves

65 Applicability of Terzaghi’s theory

66 e-log  ’ v curves

67 Variation of permeability with consolidation pressure

68  v =25 kPa Pore pressure inside and in between the lumps Inter-lump voids with waterInter-lump voids filled with slurry Inside the lump In between the lumps Inside the lump In between the lumps kPa

69 Pore pressure inside and in between the lumps Inter-lump voids with waterInter-lump voids filled with slurry Inside the lump In between the lumps  v =100 kPa

70 Influence of swelling of lumps Swelling test To find the time required for different degrees of swelling Degree of Swelling, U s w = moisture content of the specimens after immersing in water at any instant of time w i = initial moisture content of the specimen w f = moisture content of the fully swollen specimen Time UsUs For a cubical lump of 25 mm, t 50 =20 min 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

71 State of the lumpy fill under  v ’ = 50 kPa (25 mm lumps) U s = 0% U s =50% U s =100%

72 Swelling of clay lumps

73 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

74 Soils used Kaolinite: LL=82%, PL=40% Cylindrical samples of 105, 205 and 400 mm Marine clay: LL=56%, PL=33% Cylindrical samples of 105 and 205 mm Three dimensional swelling of clay lumps PPTTensiometer 28 mm 12 mm Instrument used 6 mm diameter

75 240 mm T PPT Performance of PPT in comparison with Tensiometer during desiccation

76 Lump EXPERIMENTAL PROCEDURE Outer container Filter Split mould Load Water

77 Schematic of the split mould for conducting swelling test

78 View of the split mould for conducting swelling test Pneumatic piston Split mould Outer container

79 400 mm View of the kaolinite lump of 400 mm diameter after removing the split mould

80 Dissipation of suction on submerging the kaolinite lump of 400 mm diameter in water

81 Normalized suction at the centre of marine clay lumps

82 Initial state End state Kaolinite Marine clay

83 Variation of water content within the marine clay lump of 205 mm diameter after full swelling wowo wlwl

84 wLwL wowo Water content variation within the lump-Undisturbed Cube : 50 mm

85 Finite Element Analysis

86 Finite Element mesh Finite Element Analysis

87 PropertyKaolinite Marine clay ’o’o’o’o2523 KoKoKoKo E in kPa  k v in m/s e=1.21log(k v )+11.2e=0.912 log(k v )+9.8 k h /k v Soil Parameters

88 (1) Linear Elastic LE (2) Non-linear Elastic (NLE1) NLE1 (3) Non-linear Elastic (NLE2)  = log (OCR) NLE2 (4) NLE2 -Permeability increased (4) Effect of soil model (Kaolinite lump 105 mm diameter) Acknowledgement: Dr. Ganeswara Rao Dasari

89 Predicted and measured suctions at the centre of marine clay lumps

90 1.4m 1.5m Big Tank Experiment

91 SAMPLE PREPARATION DREDGED & PLACED IN A FLAT BARGE PACKED IN BAGS & TRANSPORTED TO THE LAB CUT TO CUBICAL LUMPS OF 150 MM STORED IN CONTAINERS AFTER COVERING WITH CLING-FILM

92 Size of lumps: 15 cm No. of lumps: 223 No. of layers: 6 Total weight: 1.37t Height of fill: 93 cm

93  Overview  Coastal reclamation  Lumpy fill  Laboratory studies on lumpy fill  Field tests  Conclusions Contents of Presentation

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95   Density is related to scattering of gamma ray   Cesium source Cs 137 with half life of 37.6 years   Housed in standard CPT:   Diameter = 35.6 mm   Cone angle = 60    Cone area = 10 cm 2   Penetration = 1.5 cm/sec NUCLEAR DENSITY CONE ND-CPT

96 Calibration Curve Density Count Ratio (R p ) = [RI Count – BG Count ] / Standard Count

97 LUMPY FILL TEST SITE AT PULAU PUNGGOL TIMOR  Reclaimed  14 years ago  8 m dredged fill &  10 m sand fill

98 Test Plan   Very dense grid: 79 ND-CPT 5 CPTS 11 Boreholes   Spacing 0.5 m at centre to 6 m at periphery 25.5 m 22 m

99 Final density of lumpy fill

100 Final shear strength of lumpy fill Cone Penetration TestUU Test 0.23  ’ v

101 Oedometer test results OCR=1 OCR=2

102  Overview  Coastal reclamation  Lumpy fill  Laboratory studies on lumpy fill  Field tests  Conclusions Contents of Presentation

103 SOME ISSUES  Time-settlement of lumpy fill Double porous Double porous Heterogeneous initial condition Heterogeneous initial condition Pore pressure generation and dissipation Pore pressure generation and dissipation  Swelling of clay lumps Time-swell Time-swell End state End state

104 Acknowledgements NSTB and HDB for funding Toa Corporation: Contractors for reclamation Kiso-Jiban: Contractors for in-situ Testing Researchers: Mr. M. KarthikeyanResearch Engineer Mr. Yang Li-AngResearch Engineer Mr. A VijayakumarResearch Scholar Ms. Goh Wen JeanFYP Ms. Lim Chea RongFYP Ms. Lim Hsiao ChernFYP Mr. Lim Chee KiongFYP

105 Had Useful discussions with: Dr. D. W. HightGeotechnical Consulting Group, London, UK Prof. J. LocatLaval University, Canada Dr. H. TanakaPort and Airport Research Institute, Japan Prof. M. MimuraKyoto University, Japan Mr. M. NobuyamaSoil and Rock Engg. Co. Ltd., Japan Prof. J.TakemuraTokyo Institute of Technology, Japan

106 Thank you


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