Groundwater lowering in construction : a practical guide to dewatering

Description

"Construction requires dry, stable and safe soil conditions, which frequently requires the reduction of pore pressures or groundwater levels.This established professional guide covers the design, construction and environmental management of groundwater control and dewatering works for construction projects. It is practically oriented and written for practising construction professionals, whether engineers, geologists or hydrogeologists, and Masters level students. It is well illustrated with case studies.Changes have been made to this new edition to reflect the considerable developments in environmental management practice and procedures and in the regulations related to groundwater control. The book contains a brand new chapter on permanent dewatering systems, and heavily revised coverage of other dewatering systems, environmental impacts, and the design of groundwater lowering systems, and coverage of specialist topics such as the management of water from sump pumping and wellpointing for deeper excavations"--  Read more... 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