-Craney Island Eastward Expansion Hydraulically Constructed Dikes - - PowerPoint PPT Presentation

▶
craney island eastward expansion hydraulically
SMART_READER_LITE
LIVE PREVIEW

-Craney Island Eastward Expansion Hydraulically Constructed Dikes - - PowerPoint PPT Presentation

Apr 17, 2023 119 likes •507 views

-Craney Island Eastward Expansion Hydraulically Constructed Dikes 40 Years of Dredging and Environmental Innovation P R E S E N T E D B Y: I R A B ROT M A N , P E M O F FAT T & N I C H O L O C T O B E R 2 5 , 2 0 1 2

slide-1
SLIDE 1

P R E S E N T E D B Y:

I R A B ROT M A N , P E M O F FAT T & N I C H O L

O C T O B E R 2 5 , 2 0 1 2

  • Craney Island Eastward Expansion

Hydraulically Constructed Dikes

“40 Years of Dredging and Environmental Innovation”

slide-2
SLIDE 2

Craney Island Eastward Expansion

slide-3
SLIDE 3

CIEE Layout

I

Existing CIDMMA CIDMMA East Dike CIEE Main Dike CIEE Cross Dike (typ)

slide-4
SLIDE 4

Subsurface Stratigraphy

slide-5
SLIDE 5

CIDMMA Dikes (1954)

slide-6
SLIDE 6

CIDMMA Dikes (1954)

slide-7
SLIDE 7

CIDMMA Dikes (1954)

slide-8
SLIDE 8

Cross Dike Objectives

 Experiences with CIDMMA (built to +5’)  Minimize Mud Waves  Minimize Deformation  Minimize Instability – Now and Future  Minimize Ultimate Sand Volume  Predictable Schedule

slide-9
SLIDE 9

Cross Dike Alternatives

 High strength geotextile/geogrid  Pre-dredge  Deep Soil Mixing  Prefabricated Vertical Drains (PVD)

 Build dikes in lifts/stages  Allow increase in shear strength  Achieve by specifying lift thicknesses and hold times

slide-10
SLIDE 10

Distance in feet (x 1000)

0.50

  • 0.45
  • 0.40
  • 0.35
  • 0.30
  • 0.25
  • 0.20
  • 0.15
  • 0.10
  • 0.05

0.0 0.0 5 0.1 0.1 5 0.2 0.2 5 0.3 0.3 5 0.4 0.4 5

Elevation in feet (MLLW)

  • 16
  • 14
  • 12
  • 10
  • 80
  • 60
  • 40
  • 20

20 40 60

Selected Low Cost, Low Risk Cross Dike

  • Final target elevation = +18 ft (MLLW)
  • 900 ft Wide
  • Built in 3 Stages

Upper Norfolk Clay (Qnu)

Pleistocene/Pliocene Sands (Qnl/Tys)

PVDs

Hydraulic Sand Fill Zone of PVDs

Marine PVDs Marine PVDs Land PVDs

slide-11
SLIDE 11

Construction Sequence

 Place Initial Lift  Install Marine PVDs

 Initiate Strength Gain

 Place Second Lift

 Allow Additional Strength Gain

 Place Third Lift

slide-12
SLIDE 12

South and Division Cross Dikes

slide-13
SLIDE 13

Cross Dikes – Stage 1

Hydraulic Sand Fill, Stage 1

slide-14
SLIDE 14

Cross Dikes Stage 1 – Marine PVDs

PVDs Outer 3rd

PVDs PVDs

slide-15
SLIDE 15

Cross Dikes Stage 2A – Sand Fill

Hydraulic Sand Fill, Stage 2A

slide-16
SLIDE 16

Rendering Post Stage 3

slide-17
SLIDE 17

Rendering Southeast Cell Closed

slide-18
SLIDE 18

Borrow Source

Atlantic Ocean Channel

CIEE

slide-19
SLIDE 19

GLDD – Stage 1

slide-20
SLIDE 20

Sand Placement

slide-21
SLIDE 21
slide-22
SLIDE 22
slide-23
SLIDE 23
slide-24
SLIDE 24
slide-25
SLIDE 25
slide-26
SLIDE 26

GLDD – Stage 1 – Marine PVDs

slide-27
SLIDE 27
slide-28
SLIDE 28
slide-29
SLIDE 29

PVD Installation Record

slide-30
SLIDE 30

PVD Tip Elevations

slide-31
SLIDE 31

Multibeam Survey

slide-32
SLIDE 32

Multibeam Survey

slide-33
SLIDE 33

Geotechnical Instrumentation

slide-34
SLIDE 34

Instrumentation Website

slide-35
SLIDE 35

Settlement

slide-36
SLIDE 36

Summary

 Schedule Challenges

 TOY: Turtles

 Contractor Innovation

 Spillbarge  Specialized Barge for PVDs  Positioning /Tracking System

 Observational Method Success

 Measure behavior of foundation during filling  Validate Lift placement schedule and hold times  PVD installation verification  Control project risk

slide-37
SLIDE 37

Thank You

Special thanks to:

 Virginia Port Authority  Corps of Engineers, Norfolk District