Contenido Hydraulic Fill Manual For Dredging and Reclamation Works

Without proper hydraulic fill and suitable specialised equipment, many major infrastructure projects such as ports, airports, roads, industrial or housing projects could not be realised. Yet comprehensive information about hydraulic fill is difficult to find. This thoroughly researched book, written by noted experts, takes the reader step-by-step through the complex development of a hydraulic fill project.

Up-to-date and in-depth, this manual will enable the client and his consultant to understand and properly plan a reclamation project. It provides adequate guidelines for design and quality control and allows the contractor to work within known and generally accepted guidelines and reasonable specifications. The ultimate goal is to create better-designed, more adequately specified and less costly hydraulic fill projects.

The Hydraulic Fill Manual covers a range of topics such as:

• The development cycle of a hydraulic fill project

• How technical data are acquired and applied

• The construction methods applicable to a wide variety of equipment and soil conditions, the capabilities of dredging equipment and the techniques of soil improvement

• How to assess the potentials of a borrow pit

• Essential environment assessment issues

• The design of the hydraulic fill mass, including the boundary conditions for the design, effects of the design on its surroundings, the strength and stiffness of the fill mass, density, sensitivity to liquefaction, design considerations for special fill material such as silts, clays and carbonate sands, problematic subsoils and natural hazards

• Quality control and monitoring of the fill mass and its behaviour after construction.

This manual is of particular interest to clients, consultants, planning and consenting authorities, environmental advisors, contractors and civil, geotechnical, hydraulic and coastal engineers involved in dredging and land reclamation projects.


Table Contents

Preface

Acknowledgements

Notation

Abbreviations

1 Introduction to the manual

1.1 Land reclamation by hydraulic filling
1.2 History and prospects
1.3 Context and objectives
1.4 Design philosophy
1.5 Structure, content and use

2 Project initiation

2.1 General
2.2 Basic elements of a land reclamation project
2.2.1 Conceptual design
2.2.2 Availability of fill sources
2.2.3 Data collection
2.2.4 Environmental requirements
2.2.5 Feasibility study
2.2.6 Initial project planning
2.2.7 Legal aspects
2.2.8 Types of contracts
2.3 Design
2.3.1 Design phases
2.4 Considerations for selecting construction method
2.5 Systems Engineering

3 Data collection

3.1 Introduction
3.2 Interpretation of data, contractual aspects
3.3 Desk study
3.4 Required data
3.4.1 Bathymetrical or topographical data
3.4.2 Geological and geotechnical information
3.4.2.1 Geological and geotechnical information in the borrow area
3.4.2.2 Geological and geotechnical information of the subsoil in the reclamation area
3.4.3 Hydraulic, meteorological, morphological and environmental data
3.4.3.1 Hydraulic data
3.4.3.2 Meteorological data
3.4.3.3 Morphological and environmental data
3.4.4 Seabed obstructions
3.5 Typical sand search site investigation
3.6 Reporting
3.6.1 Soil and rock classification and description
3.6.2 Soil classification based on CPT measurements
3.7 Use of data during different project stages
3.8 Geostatistical methods
3.8.1 General
3.8.2 Methods
3.8.3 Geostatistical software

4 Dredging equipment

4.1 Introduction
4.2 Dredging equipment
4.2.1 Suction dredging
4.2.2 Mechanical dredging
4.2.3 Other types of equipment
4.2.4 Combinations of equipment or dredge chains
4.3 Operational limitations
4.3.1 Waves and swell
4.3.2 Currents
4.3.3 Hindrance to shipping and other parties
4.3.4 Environmentally driven limitations
4.4 Dredging of fill material
4.4.1 Introduction
4.4.2 Volume and dimensions of borrow area
4.4.3 Minimum thickness of fill deposits
4.4.4 Dredgeability
4.5 Transport of fill
4.5.1 Introduction
4.5.2 Hydraulic transport through a pipeline
4.5.3 Transport by trailing suction hopper dredger or barge
4.6 Utilisation characteristics of dredging equipment
4.7 Basis of cost calculation for dredging

5 Selection borrow area

5.1 Considerations for the selection of a borrow area
5.2 Quality of the potential fill material
5.2.1 Change of the grading as a result of dredging
5.2.2 Alternative fill materials
5.3 Data collection in the borrow area
5.3.1 Data collection for quality assessment
5.3.2 Data collection for quantity assessment
5.3.3 Data collection for dredgeability assessment
5.4 Quantity of fill material available
5.4.1 Bulking
5.4.2 Losses
5.4.3 Slope stability
5.4.4 Geo-statistical methods
5.5 Boundary conditions

6 Planning and construction methods reclamation

6.1 Planning of the works
6.1.1 Introduction
6.1.2 Work preparation
6.1.2.1 Establishment of project team
6.1.2.2 Provision of housing and offices for personnel
6.1.2.3 Execution of engineering works
6.1.2.4 Create access to site and development of lay-down areas
6.1.2.5 Preparation and mobilization of equipment
6.1.3 Construction and monitoring
6.1.4 Demobilisation, clean-up and maintenance
6.1.5 Example of a project schedule
6.2 Work plan for reclamation works
6.3 Placement methods
6.4 Construction of containment bunds
6.4.1 General
6.4.2 Methods of bund construction
6.5 Placement of fill material
6.5.1 Underwater placement in bulk of fill material
6.5.2 Placement of fill material using a discharge pipeline
6.5.3 Rainbowing
6.5.4 Spraying
6.6 Fill mass properties related to method of placement
6.7 Management of poor quality materials
6.7.1 Use of cohesive or fine grained materials
6.7.2 Settling ponds

7 Ground improvement

7.1 Introduction
7.2 Benefits of ground improvement
7.3 Overview of ground improvement techniques
7.4 Pre-loading with or without vertical drains
7.4.1 Purpose and principle of pre-loading
7.4.2 Vertical drains
7.5 Compaction
7.5.1 Introduction
7.5.2 Vibratory surface compaction
7.5.3 Deep vibratory compaction
7.5.3.1 General
7.5.3.2 Vibratory probes without jets
7.5.3.3 Vibroflotation
7.5.4 Dynamic compaction techniques
7.5.5 Explosive compaction
7.6 Soil replacement
7.6.1 Introduction
7.6.2 Soil removal and replacement
7.6.3 Stone columns
7.6.3.1 Purpose and principle
7.6.3.2 Execution of stone columns by the vibro-replacement technique
7.6.4 Sand compaction piles (closed end casing)
7.6.5 Geotextile encased columns
7.6.6 Dynamic replacement
7.7 Admixtures and in-situ soil mixing

8 Design of reclamation area

8.1 Design philosophy
8.2 Basic mass properties
8.2.1 Strength of fill mass: Bearing capacity and slope stability
8.2.2 Stiffness of fill mass: Settlements, horizontal deformations and tolerances
8.2.3 Density of the fill mass and subsoil: Resistance against liquefaction
8.2.4 Permeability of fill mass: Drainage capacity
8.2.5 Platform level: Safety against flooding and erosion
8.3 Density
8.3.1 Definition of key parameters
8.3.2 Density ratios
8.3.3 The use of densities or density ratios in specifications
8.3.4 Effect of grain size distribution on the density of a soil sample
8.3.5 Density measurement
8.3.5.1 Measurement of reference densities (minimum and maximum density)
8.3.5.2 Direct measurement of in situ density
8.3.5.3 Indirect measurement of relative density by cone penetration testing
8.3.5.4 Indirect measurement of relative density by SPT testing
8.3.5.5 Measurement of in situ state parameter ψ by cone penetration testing
8.3.6 Typical relative density values of hydraulic fill before compaction
8.4 Strength of the fill mass and subsoil (bearing capacity and slope stability)
8.4.1 Introduction
8.4.2 Shear strength
8.4.2.1 High quality fill material
8.4.2.2 Poor quality fill material
8.4.2.3 Assessment of shear strength
8.4.3 Relevant failure modes
8.4.3.1 Introduction
8.4.3.2 Safety approach
8.4.3.3 Analytical calculation models versus Finite Element Method (FEM)
8.4.3.4 Bearing capacity
8.4.3.5 Punch through
8.4.3.6 Squeezing
8.4.3.7 Slope stability of fill and subsoil
8.4.3.7.1 Design methods
8.4.3.7.2 Limit Equilibrium Methods
8.4.3.7.3 Finite Element Method
8.4.3.8 Construction of a slope on soft soil
8.4.3.9 Effect of groundwater flow on slope stability
8.4.3.10 Earthquakes and slope stability
8.4.3.11 Stabilising measures for slope stability
8.4.3.11.1 Optimizing the slope geometry by using counterweight berms
8.4.3.11.2 Staged construction
8.4.3.11.3 Soil replacement (sand key)
8.4.3.11.4 Stone columns, sand compaction piles
8.4.3.11.5 Geosynthetics
8.5 Stiffness and deformation
8.5.1 Introduction
8.5.2 Stiffness
8.5.2.1 General considerations
8.5.2.2 Stiffness of subsoil
8.5.2.3 Stiffness of fill material
8.5.3 Deformations
8.5.3.1 General considerations
8.5.3.2 Settlement calculation methods
8.5.3.3 Additional considerations
8.5.3.4 Vertical deformation of a reclamation surface
8.5.3.5 Vertical deformations of structures
8.5.3.6 Horizontal deformations
8.5.4 Techniques for limiting settlement
8.6 Liquefaction and earthquakes
8.6.1 Overview
8.6.2 History of understanding
8.6.3 Flow slides versus Cyclic softening
8.6.4 Assessing liquefaction susceptibility
8.6.4.1 Codes & Standards
8.5.4.2 Loading: Estimating CSR by site response analysis
8.6.4.3 Resistance, Step 1: Susceptibility to large deformations
8.6.4.4 Resistance, Step 2: Evaluation of CRR
8.6.5 Movements caused by liquefaction
8.6.5.1 Slope deformations
8.6.5.2 Lateral spreads
8.6.5.3 Settlements
8.6.6 Fill characterization for liquefaction assessment
8.6.6.1 Necessity for in situ tests
8.6.6.2 Required number of CPT soundings
8.6.6.3 CPT calibration
8.6.6.4 Supporting laboratory data
8.6.7 Note on soil type (Calcareous and other non-standard sands)

9 Special fill materials and problematic subsoils

9.1 Cohesive or fine-grained fill materials
9.1.1 Introduction
9.1.2 Segregation of fines
9.1.3 Soft clay or soft silt
9.1.3.1 Suitability of soft (organic) clay or silt as fill material
9.1.3.2 Workability of clay
9.1.3.3 Effects of winning method
9.1.3.4 Measures to improve the fill properties after disposal
9.1.3.5 Construction aspects of soft soils in case of application above the waterline
9.1.3.6 Construction aspects of soft soils in case of application below the waterline
9.1.4 Stiff clay or silt
9.2 Carbonate sand fill material
9.2.1 Introduction
9.2.2 Origin and composition of carbonate sands
9.2.3 Typical properties of carbonate sands
9.2.4 Mechanical behaviour of carbonate sands
9.2.5 The use of carbonate sand as fill
9.2.5.1 Typical behaviour during dredging and hydraulic transport
9.2.5.2 Cone Penetration and Standard Penetration testing in carbonate sands
9.2.5.3 Laboratory testing
9.2.5.4 Field compaction
9.3 Hydraulic rock fill
9.3.1 Introduction
9.3.2 Lump size
9.3.3 Compaction and measurement of compaction result
9.3.4 Grading
9.3.5 Fines
9.3.6 Wear and tear
9.3.7 Pumping distance during rock dredging
9.3.8 Specifications rock fill
9.4 Problematic subsoils
9.4.1 Sensitive clay
9.4.2 Peat
9.4.3 Glacial soils
9.4.4 Sabkha
9.4.5 Karst
9.4.6 Laterite

10 Other design items

10.1 Introduction
10.2 Drainage
10.2.1 Infiltration
10.2.2 Surface runoff
10.2.3 Artificial drainage systems
10.3 Wind erosion
10.4 Slope, bank and bed protection
10.5 Interaction between reclamation and civil works
10.5.1 General
10.5.2 Foundations
10.5.3 Construction sequence
10.5.4 Impact on existing structures
10.6 Earthquakes
10.7 Tsunamis

11 Monitoring and quality control

11.1 Introduction
11.2 Quality Control Plan
11.3 Monitoring and testing
11.3.1 Geometry
11.3.2 Fill material properties
11.3.2.1 Grain size distribution
11.3.2.2 Minimum and maximum dry densities
11.3.2.3 Mineralogy
11.3.3 Fill mass properties
11.3.3.1 Shear strength
11.3.3.2 Stiffness
11.3.3.3 Density, relative compaction and relative density
11.3.4 Environmental monitoring

12 Technical specifications

12.1 Introduction
12.2 Roles and responsibilities
12.3 Checklist project requirements
12.4 Commented examples of technical specifications
12.4.1 Introduction
12.4.2 Description of the works
12.4.3 Standards
12.4.4 Data collection (see Chapter 3)
12.4.5 Dredging equipment and working method (see Chapter 4)
12.4.6 Selection borrow area—quality fill material (see Chapter 5)
12.4.7 Construction methods reclamation area (see Chapter 6)
12.4.8 Environmental impact
12.4.9 Design of a land reclamation (see Chapter 8)
12.4.10 Ground improvement (see Chapter 7)
12.4.11 Special fill materials (see Chapter 9)
12.4.12 Other design aspects (see Chapter 10)
12.4.13 Monitoring and quality control (see Chapter 11)
12.4.13.1 Geometry
12.4.13.2 Testing fill material properties (see Section 11.3.2)
12.4.13.3 Testing fill mass properties (see Section 11.3.3)
12.4.13.4 Settlement monitoring (see Appendix B.5.3)
12.4.13.5 Performance testing
12.4.13.6 Reporting
12.4.13.7 Monitoring and Quality Control Program (see Section 11.2)

Appendices

A Equipment
B Field and Laboratory Tests
C Correlations and Correction Methods
D Geotechnical Principles
References