Groundwater Lowering in Construction: A Practical Guide to Dewatering, Second Edition

✍ Scribed by Pat M. Cashman (Author); Martin Preene (Author)

• Publisher: CRC Press
• Year: 2012
• Leaves: 665
• Edition: 2
• Category: Library

✦ Synopsis

Linking theory and application in a way that is clear and understandable, Groundwater Lowering in Construction: A Practical Guide to Dewatering, Second Edition uses the authors’ extensive engineering experience to offer practical guidance on the planning, design, and implementation of groundwater control systems under real conditions.

Discover engineering methods that can help you improve working conditions, increase project viability, and reduce excavation costs.

In the decade since publication of this book’s first edition, groundwater lowering and dewatering activities have been increasingly integrated into the wider ground engineering schemes on major excavations to help provide stable and workable conditions for construction below groundwater level. Consequently, many engineering ventures now require a more in-depth assessment of potential environmental impacts of dewatering and groundwater control, and this book details the latest best practices to evaluate and address them.

Includes New Chapters Covering:

• Cutoff methods used for groundwater exclusion
• Issues associated with permanent or long-term groundwater control systems
• Groundwater control technologies used on contaminated sites
• Methods needed to understand, predict, and mitigate potential environmental impacts of groundwater control works

Updated to reflect the crucial technological and application advances shaping construction processes, this book contains valuable direction that can give you a true competitive advantage in the planning and execution of temporary and permanent dewatering works. The authors cover cutting-edge methods and key subjects, such as the history of dewatering, working on contaminated sites, site investigation techniques, and operation and maintenance issues, including health, safety, and legal aspects. Written for practising engineers and geologists as well as postgraduate engineering students, this updated manual on design and practice provides numerous case histories and extensive references to enhance understanding.

✦ Table of Contents

Groundwater lowering: A personal view,P.Cashman

Structure of the rest of the book

History of groundwater theory and practice

Earliest times to the sixteenth century

Renaissance period to the nineteenth century

Progress from a qualitative to a quantitative science

Later theoretical developments

Groundwater modeling

Early dewatering technology in Britain

Practical publications

Groundwater and permeability

Hydrology and hydrogeology

Permeability and groundwater flow

Aquifers, aquitards, and aquicludes

Flow to wells

Aquifers and geological structure

Aquifer boundaries

Using geological structure to advantage

Groundwater chemistry

Groundwater effects on the stability of excavations

Groundwater control—the objectives

Groundwater, effective stress, and instability

Large-scale instability caused by groundwater

Slope instability

Base instability

Localized groundwater problems

Excavations in rock

Surface water problems

Effect of climate and weather

Methods for control of surface water and groundwater

Control of surface water

Methods of groundwater control

Exclusion methods

Dewatering methods

Groundwater control for tunnels and shafts

Use of pumping and exclusion methods in combination

Site investigation for groundwater lowering

Purpose of site investigation

Planning of site investigations

Stages of site investigation

Determination of ground profile

Determination of groundwater conditions

Determination of permeability

Design of groundwater lowering systems

What is design?

Design approach

Development of a conceptual model

Expectations of accuracy

Selection of method and geometry

Estimation of steady-state discharge flow rate

Specification of well yield and spacing

Other considerations

Numerical modeling

Sump pumping

Applications of sump pumping

Pumping of surface water runoff

Pumping sumps

Drainage of side slopes of an excavation

Sump pumping of small excavations

Sump pumping problems

Disposal of water from sump pumping operations

Case history: Sump pumping of large excavation

Wellpoint systems

Which system: Wellpoints or deep wells?

What is a wellpoint system?

Wellpoint installation techniques

Spacing of wellpoints and drawdown times

Sealed vacuum wellpoint system

Wellpoint pumping equipment

Wellpoint installations for trench excavations

Wellpointing for wide excavations

Wellpointing for deeper excavations

Case history: Derwent outlet channel, Northumberland

Deep well systems

Deep well installations

Design of wells for groundwater lowering

Constructing deep wells

Drilling of well boreholes

Installation of well materials

Well development

Installation and operation of deep well pumps

Vacuum deep well installations

Shallow well installations

Case history: Tees barrage, Stockton-on-Tees

Other dewatering systems

Ejectors

Horizontal wellpoints

Horizontal wells

Pressure relief wells

Collector wells

Siphon drains

Electro-osmosis

Artificial recharge systems

Dewatering and groundwater control technologies used for the control or remediation of contaminated groundwater

Methods for the exclusion of groundwater

Principal methods for groundwater exclusion

Geometries of exclusion applications

Steel sheet piling

Vibrated beam walls

Slurry trench walls

Concrete diaphragm walls

Bored pile walls

Grout barriers

Mix-in-place barriers

Artificial ground freezing

Pumps for groundwater lowering duties

Wellpoint pumps

Jetting pumps

Sump pumps

Pumps for deep wells

Sizing of pumps and pipework

Permanent groundwater control systems

Types of permanent groundwater control systems

Objectives of permanent groundwater control systems

Design issues for permanent groundwater control systems

Practical issues for permanent groundwater control systems

Opportunities associated with permanent groundwater control systems

Case history: Govan underground tunnel, Glasgow

Environmental impacts from groundwater control

Why are impacts from groundwater control of concern?

Potential environmental impacts from groundwater control

Impacts from groundwater abstraction

Impacts from groundwater pathways

Impacts from groundwater barriers

Impacts from discharge flows to the groundwater environment

Impacts from discharge flows to the surface water environment

Assessment of potential environmental impacts

Monitoring and maintenance of groundwater lowering systems

Need for monitoring

Monitoring of water levels

Monitoring of discharge flow rate

Other parameters that may be monitored

Data-logging systems

Mechanical factors and automation

Backfilling and sealing of wells on completion

Encrustation, biofouling, and corrosion

Fault finding and problem solving

Safety, contracts, and environmental regulation

Health and safety

Contracts for groundwater control works

The future—a personal perspective by Toby Roberts

Applications and techniques

Communication and monitoring technology

Numerical modeling

Regulation

Where do we go from here?

Next generation of dewatering practitioners

Appendix 1: Estimation of permeability from laboratory data—Loudon method

Appendix 2: Execution and analysis of variable head permeability tests in boreholes

Appendix 3: Execution of well pumping tests

Appendix 4: Design examples

Appendix 5: Estimation of flow rate using V-notch weirs

List of notation

Glossary

List of conversion factors

References

✦ Subjects

Engineering & Technology;Civil, Environmental and Geotechnical Engineering;Hydraulic Engineering;Soil Mechanics;Water Engineering;Mining, Mineral & Petroleum Engineering;Mining Engineering;Mining Construction