Geotechnical Engineering of Dams, 2nd Edition
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|Format: ||Hardcover, 1348 pages, 2nd Revised Edition|
|Other Information: ||Illustrated|
|Published In: ||United Kingdom, 01 December 2014|
Geotechnical Engineering of Dams, 2nd edition provides a comprehensive text on the geotechnical and geological aspects of the investigations for and the design and construction of new dams and the review and assessment of existing dams. The main emphasis of this work is on embankment dams, but much of the text, particularly those parts related to geology, can be used for concrete gravity and arch dams. All phases of investigation, design and construction are covered. Detailed descriptions are given from the initial site assessment and site investigation program through to the preliminary and detailed design phases and, ultimately, the construction phase. The assessment of existing dams, including the analysis of risks posed by those dams, is also discussed. This wholly revised and significantly expanded 2nd edition includes a lengthy new appendix on the assessment of the likelihood of failure of dams by internal erosion and piping. This valuable source on dam engineering incorporates the 200+ years of collective experience of the authors in the subject area. Design methods are presented in combination with their theoretical basis, to enable the reader to develop a proper understanding of the possibilities and limitations of a method. For its practical, well-founded approach, this work can serve as a useful guide for professional dam engineers and engineering geologists and as a textbook for university students.
Table of Contents
Author Biographies 1 Introduction 1.1 Outline of the book 1.2 Types of embankment dams and their main features 1.3 Types of concrete dams and their main features 2 Key geological issues 2.1 Basic definitions 2.2 Types of anisotropic fabrics 2.3 Defects in rock masses 2.3.1 Joints 2.3.2 Sheared and crushed zones (faults) 2.3.3 Soil infill seams (or just infill seams) 2.3.4 Extremely weathered (or altered) seams 2.3.5 The importance of using the above terms to describe defects in rock 2.4 Defects in soil masses 2.5 Stresses in rock masses 2.5.1 Probable source of high horizontal stresses 2.5.2 Stress relief effects in natural rock exposures 2.5.3 Effects in claystones and shales 2.5.4 Special effects in valleys 2.5.5 Rock movements in excavations 2.6 Weathering of rocks 2.6.1 Mechanical weathering 2.6.2 Chemical decomposition 2.6.3 Chemical weathering 22.214.171.124 Susceptibility of common minerals to chemical weathering 126.96.36.199 Susceptibility of rock substances to chemical weathering 2.6.4 Weathered rock profiles and their development 188.8.131.52 Climate and vegetation 184.108.40.206 Rock substance types and defect types and pattern 220.127.116.11 Time and erosion 18.104.22.168 Groundwater and topography 22.214.171.124 Features of weathered profiles near valley floors 2.6.5 Complications due to cementation 2.7 Chemical alteration 2.8 Classification of weathered rock 2.8.1 Recommended system for classification of weathered rock substance2.8.2 Limitations on classification systems for weathered rock 2.9 Rapid weathering 2.9.1 Slaking of mudrocks 2.9.2 Crystal growth in pores 2.9.3 Expansion of secondary minerals 2.9.4 Oxidation of sulphide minerals 126.96.36.199 Sulphide oxidation effects in rockfill dams - some examples 188.8.131.52 Possible effects of sulphide oxidation in rockfill dams 184.108.40.206 Sulphide oxidation - implications for site studies 2.9.5 Rapid solution 2.9.6 Surface fretting due to electro-static moisture absorption 2.10 Landsliding at dam sites 2.10.1 First-time and "reactivated'' slides 220.127.116.11 Reactivated slides 18.104.22.168 First-time slides 2.10.2 Importance of early recognition of evidence of past slope instability at dam sites 2.10.3 Dams and landslides: Some experiences 22.214.171.124 Talbingo Dam 126.96.36.199 Tooma Dam 188.8.131.52 Wungong Dam 184.108.40.206 Sugarloaf Dam 220.127.116.11 Thomson Dam 2.11 Stability of slopes around storages 2.11.1 Vital slope stability questions for the feasibility and site selection stages 18.104.22.168 Most vulnerable existing or proposed project features, and parts of storage area? - Question 1 22.214.171.124 Currently active or old dormant landslides? - Questions 2 and 4 to 126.96.36.199 Areas where first-time landsliding may be induced (Questions 3 to 7) 188.8.131.52 What is the likely post failure velocity and travel distance? 184.108.40.206 What is the size of impulse waves which may be created? 2.12 Watertightness of storages 2.12.1 Models for watertightness of storages in many areas of non-soluble rocks 2.12.2 Watertightness of storage areas formed by soluble rocks 2.12.3 Features which may form local zones of high leakage, from any storage area 2.12.4 Watertightness of storages underlain by soils 2.12.5 Assessment of watertightness 220.127.116.11 Storages in non-soluble rock areas - assessment of watertightness 18.104.22.168 Storages in soluble rock areas - assessment of watertightness 22.214.171.124 Storages formed in soils - assessment of watertightness 2.12.6 Methods used to prevent or limit leakages from storages 3 Geotechnical questions associated with various geological environments 3.1 Granitic rocks 3.1.1 Fresh granitic rocks, properties and uses 3.1.2 Weathered granitic rocks, properties, uses and profiles 3.1.3 Stability of slopes in granitic rocks 3.1.4 Granitic rocks: check list 3.2 Volcanic rocks (intrusive and flow) 3.2.1 Intrusive plugs, dykes and sills 3.2.2 Flows 126.96.36.199 Flows on land 188.8.131.52 Undersea flows 3.2.3 Alteration of volcanic rocks 3.2.4 Weathering of volcanic rocks 3.2.5 Landsliding on slopes underlain by weathered basalt 3.2.6 Alkali-aggregate reaction 3.2.7 Volcanic rocks (intrusive and flow) check list of questions 3.3 Pyroclastics 13.3.1 Variability of pyroclastic materials and masses 3.3.2 Particular construction issues in pyroclastics 3.3.3 Pyroclastic materials - check list of questions 3.4 Schistose rocks 3.4.1 Properties of fresh schistose rock substances 3.4.2 Weathered products and profiles developed in schistose rock 3.4.3 Suitability of schistose rocks for use as filter materials, concrete aggregates and pavement materials 3.4.4 Suitability of schistose rocks for use as rockfill 3.4.5 Structural defects of particular significance in schistose rocks 184.108.40.206 Minor faults developed parallel and at acute angles to the foliation 220.127.116.11 Kink bands 18.104.22.168 Mica-rich layers 3.4.6 Stability of slopes formed by schistose rocks 3.4.7 Schistose rocks - check list of questions 3.5 Mudrocks 3.5.1 Engineering properties of mudrocks 3.5.2 Bedding-surface faults in mudrocks 3.5.3 Slickensided joints or fissures 3.5.4 Weathered products and profiles in mudrocks 3.5.5 Stability of slopes underlain by mudrocks 3.5.6 Development of unusually high pore pressures 3.5.7 Suitability of mudrocks for use as construction materials 3.5.8 Mudrocks - check list of questions 3.6 Sandstones and related sedimentary rocks 3.6.1 Properties of the rock substances 3.6.2 Suitability for use as construction materials 3.6.3 Weathering products 3.6.4 Weathered profile and stability of slopes 3.6.5 Sandstones and similar rocks - list of questions 3.7 Carbonate rocks 3.7.1 Effects of solution 22.214.171.124 Rock masses composed of dense, fine grained rock substances comprising more than 90% of carbonate (usually Category O) 126.96.36.199 Rock masses composed of dense fine grained rock substance containing 10% to 90% of carbonate (usually Category O) 188.8.131.52 Rock masses composed of porous, low density carbonate rock substance (usually Category Y) 3.7.2 Watertightness of dam foundations 184.108.40.206 Dams which have experienced significant leakage problems 3.7.3 Potential for sinkholes to develop beneath a dam, reservoir or associated works 3.7.4 Potential for continuing dissolution of jointed carbonate rock in dam foundations 3.7.5 Potential for continuing dissolution of aggregates of carbonate rock particles and of permeable carbonate substances (Category O carbonate, in each case) 3.7.6 Discussion - potential for continuing dissolution of carbonate rocks in foundations 220.127.116.11 Category O carbonate rocks 18.104.22.168 Category Y carbonate rocks 3.7.7 Potential problems with filters' composed of carbonate rocks 22.214.171.124 Category O carbonate rocks 126.96.36.199 Category Y carbonate materials 3.7.8 Suitability of carbonate rocks for embankment materials 3.7.9 Suitability of carbonate rocks for concrete and pavement materials 3.7.10 Stability of slopes underlain by carbonate rocks 3.7.11 Dewatering of excavations in carbonate rocks 3.7.12 Carbonate rocks - check list of questions 3.8 Evaporites 3.8.1 Performance of dams built on rocks containing evaporites 3.8.2 Guidelines for dam construction at sites which contain evaporites 3.8.3 Evaporites - checklist of questions 3.9 Alluvial soils 3.9.1 River channel deposits 3.9.2 Open-work gravels 3.9.3 Oxbow lake deposits 3.9.4 Flood plain, lacustrine and estuarine deposits 3.9.5 Use of alluvial soils for construction 3.9.6 Alluvial soils, list of questions 3.10 Colluvial soils 3.10.1 Occurrence and description 188.8.131.52 Scree and talus 184.108.40.206 Slopewash soils 220.127.116.11 Landslide debris 3.10.2 Properties of colluvial soils 18.104.22.168 Scree and talus 22.214.171.124 Slopewash 126.96.36.199 Landslide debris 3.10.3 Use as construction materials 3.10.4 Colluvial soil - list of questions 3.11 Laterites and lateritic weathering profiles 3.11.1 Composition, thicknesses and origin of lateritic weathering profiles 3.11.2 Properties of lateritic soils 3.11.3 Use of lateritic soils for construction 3.11.4 Karstic features developed in laterite terrain 3.11.5 Recognition and interpretation of silcrete layer 3.11.6 Lateritic soils and profiles - list of questions 3.12 Glacial deposits and landforms 3.12.1 Glaciated valleys 3.12.2 Materials deposited by glaciers 188.8.131.52 Properties of till materials 184.108.40.206 Disrupted bedrock surface beneath glaciers 3.12.3 Glaciofluvial deposits 3.12.4 Periglacial features 3.12.5 Glacial environment - list of questions 4 Planning, conducting and reporting of geotechnical investigations 4.1 The need to ask the right questions 4.1.1 Geotechnical engineering questions 4.1.2 Geological questions 220.127.116.11 Questions relating to rock and soil types, climate and topography 18.104.22.168 Questions relating to geological processes, i.e. to the history of development of the site 4.1.3 Geotechnical questions for investigations of existing dams 4.2 Geotechnical input at various stages of project development 4.3 An iterative approach to the investigations 4.4 Progression from regional to local studies 4.4.1 Broad regional studies 22.214.171.124 Objectives 126.96.36.199 Activities 4.4.2 Studies at intermediate and detailed scales 188.8.131.52 Objectives 184.108.40.206 Activities 4.5 Reporting 4.6 Funding of geotechnical studies 4.7 The site investigation team 5 Site investigation techniques 5.1 Topographic mapping and survey 5.2 Interpretation of satellite images aerial photographs and photographs taken during construction 5.2.1 Interpretation of satellite images 5.2.2 Interpretation of aerial photographs 220.127.116.11 Coverage 18.104.22.168 Interpretation 5.2.3 Photographs taken during construction 5.3 Geomorphological mapping 5.4 Geotechnical mapping 5.4.1 Use of existing maps and reports 5.4.2 Geotechnical mapping for the project 22.214.171.124 Regional mapping 126.96.36.199 Geotechnical mapping 5.5 Geophysical methods, surface and downhole 5.5.1 Surface geophysical methods 188.8.131.52 Seismic refraction 184.108.40.206 Self potential 220.127.116.11 Electrical resistivity 18.104.22.168 Electromagnetic conductivity 22.214.171.124 Magnetic 126.96.36.199 Microgravity 188.8.131.52 Ground penetrating radar 5.5.2 Down-hole logging of boreholes 5.5.3 Cross-hole and up-hole seismic 5.6 Test pits and trenches 5.6.1 Test pits 5.6.2 Trenches 5.7 Sluicing 5.8 Adits and shafts 5.9 Drill holes5.9.1 Drilling objectives 5.9.2 Drilling techniques and their application 5.9.3 Auger drilling 5.9.4 Percussion drilling 5.9.5 Rotary drilling 5.9.6 Sonic drilling 5.10 Sampling 5.10.1 Soil samples 5.10.2 Rock samples 5.11 In situ testing 5.11.1 In situ testing in soils 5.11.2 In situ testing of rock 184.108.40.206 Borehole orientation 220.127.116.11 Borehole impression packer 18.104.22.168 Borehole imaging 5.12 Groundwater5.13 In situ permeability tests on soil 5.14 In situ permeability tests in rock 5.14.1 Lugeon value and equivalent rock mass permeability 5.14.2 Test methods 5.14.3 Selection of test section 5.14.4 Test equipment 22.214.171.124 Packers 126.96.36.199 Water supply system 188.8.131.52 Selection of test pressures 5.14.5 Test procedure 184.108.40.206 Presentation and interpretation of results 5.15 Use of surface survey and borehole inclinometers 5.15.1 Surface survey 5.15.2 Borehole inclinometers 5.16 Common errors and deficiencies in geotechnical investigation 6 Shear strength, compressibility and permeability of embankment materials and soil foundations 6.1 Shear strength of soils6.1.1 Drained strength - definitions 6.1.2 Development of drained residual strength Ï R6.1.3 Undrained strength conditions 6.1.4 Laboratory testing for drained strength parameters, and common errors 220.127.116.11 Triaxial test 18.104.22.168 Direct shear test 22.214.171.124 Ring shear test 126.96.36.199 Comparison of field residual with laboratory residual strength obtained from direct shear and ring shear 6.1.5 Laboratory testing for undrained strength 6.1.6 Estimation of the undrained strength from the Over-Consolidation Ratio (OCR), at rest earth pressure coefficient Ko, and effective stress strengths 188.8.131.52 Estimation of undrained strength from OCR 184.108.40.206 Estimation of undrained strength from effective stress shear parameters 6.1.7 Estimation of the undrained strength of cohesive soils from in situ tests 220.127.116.11 Cone Penetration and Piezocone Tests 18.104.22.168 Vane shear 22.214.171.124 Self Boring Pressuremeter 6.1.8 Shear strength of fissured soils 126.96.36.199 The nature of fissuring, and how to assess the shear strength 188.8.131.52 Triaxial testing of fissured soils 6.1.9 Estimation of the effective friction angle of granular soils 184.108.40.206 Methods usually adopted 220.127.116.11 In situ tests 18.104.22.168 Laboratory tests 22.214.171.124 Empirical estimation 6.1.10 Shear strength of partially saturated soils 6.2 Shear strength of rockfill 6.3 Compressibility of soils and embankment materials 6.3.1 General principles 126.96.36.199 Within the foundation188.8.131.52 Within the embankment 6.3.2 Methods of estimating the compressibility of earthfill, filters and rockfill 184.108.40.206 Using data from the performance of other dams - earthfill 220.127.116.11 Using data from the performance of other dams - rockfill 18.104.22.168 In situ testing 22.214.171.124 Laboratory testing 126.96.36.199 Tensile properties of plastic soils 6.4 Permeability of soils 6.4.1 General principles 6.4.2 Laboratory test methods 6.4.3 Indirect test methods 188.8.131.52 Oedometer and triaxial consolidation test 184.108.40.206 Estimation of permeability of sands from particle size distribution 6.4.4 Effects of poor sampling on estimated permeability in the laboratory 6.4.5 In situ testing methods 7 Clay mineralogy, soil properties, and dispersive soils 7.1 Introduction 7.2 Clay minerals and their structure 7.2.1 Clay minerals 7.2.2 Bonding of clay minerals 220.127.116.11 Primary bonds 18.104.22.168 Secondary bonds 7.2.3 Bonding between layers of clay minerals 7.3 Interaction between water and clay minerals 7.3.1 Adsorbed water 7.3.2 Cation exchange 7.3.3 Formation of diffuse double layer 7.3.4 Mechanism of dispersion 7.4 Identification of clay minerals 7.4.1 X-ray diffraction 7.4.2 Differential Thermal Analysis (DTA) 7.4.3 Electron microscopy 7.4.4 Atterberg limits 7.4.5 The activity of the soil 7.5 Engineering properties of clay soils related to the types of clay minerals 7.5.1 Dispersivity 7.5.2 Shrink and swell characteristics 7.5.3 Shear strength 7.5.4 Erosion properties 7.6 Identification of dispersive soils 7.6.1 Laboratory tests 22.214.171.124 Emerson class number 126.96.36.199 Soil Conservation Service test 188.8.131.52 Pinhole dispersion classification 184.108.40.206 Chemical tests 220.127.116.11 Recommended approach 7.6.2 Field identification and other factors 7.7 Use of dispersive soils in embankment dams 7.7.1 Problems with dispersive soils 7.7.2 Construction with dispersive soils 18.104.22.168 Provide properly designed and constructed filters 22.214.171.124 Proper compaction of the soil 126.96.36.199 Careful detailing of pipes or conduits through the embankment 188.8.131.52 Lime or gypsum modification of the soil 184.108.40.206 Sealing of cracks in the abutment and cutoff trench 7.7.3 Turbidity of reservoir water 8 Internal erosion and piping of embankment dams and in dam foundations 8.1 The importance of internal erosion and piping to dam safety 8.2 Description of the internal erosion and piping process 8.2.1 The overall process leading to failure of a dam 8.2.2 Initiation of internal erosion 8.2.3 Continuation of erosion 8.2.4 Progression of erosion 8.2.5 Detection and intervention 8.2.6 Breach 8.3 Concentrated leak erosion 8.3.1 The overall process 8.3.2 Situations where cracking and low stress zones may be present in an embankment or the foundation 220.127.116.11 Cracking and hydraulic fracture due to cross valley differential settlement of the core 18.104.22.168 Cracking and hydraulic fracture due to cross valley arching 22.214.171.124 Cracking and hydraulic fracture due to differential settlement in the foundation under the core 126.96.36.199 Cracking and hydraulic fracture due to small scale irregularities in the foundation profile under the core 188.8.131.52 Cracking due to lack of support for the core by the shoulders of the embankment 184.108.40.206 Cracking and hydraulic fracture due to arching of the core onto the shoulders of the embankment 220.127.116.11 Crack or gap adjacent to a spillway or abutment walls and where concrete dams abut embankment dams 18.104.22.168 Crack or hydraulic fracture in poorly compacted layers in the embankment 22.214.171.124 Internal erosion associated with conduits embedded in the embankment 126.96.36.199 Cracking due to desiccation188.8.131.52 Transverse cracking caused by settlement during earthquakes 184.108.40.206 Cracking or high permeability layers due to freezing 220.127.116.11 Internal erosion initiated by the effects animal burrows and vegetation 18.104.22.168 Relative importance of conduits, spillway walls cracking mechanisms, and poorly compacted zones 8.3.3 Estimation of crack width and depth of cracking 22.214.171.124 Cracking due to differential settlement, adjacent walls 126.96.36.199 Cracks formed by collapse settlement of poorly compacted soil 8.3.4 The mechanics of erosion in concentrated leaks 188.8.131.52 The procedure for assessing whether erosion will initiate 184.108.40.206 The estimation of hydraulic shear stresses in cracks and pipes 220.127.116.11 Erosion properties of soils in the core of embankment dams - basic principles 18.104.22.168 Effect of degree of saturation of the soil 22.214.171.124 Effect of the testing method on the critical shear stress to initiate erosion (Ï c) and the erosion rate index 126.96.36.199 Effect of dispersion, slaking, soil structure and shear strength on erosion properties 8.3.5 Comparison of the hydraulic shear stress in the crack (Ï ) to the critical shear stress which will initiate erosion for the soil in the core of the embankment (Ï c) 8.4 Backward erosion 8.4.1 General description of backward erosion 8.4.2 Experimental modelling of backward erosion piping 8.4.3 Methods for predicting whether backward erosion piping will initiate and progress 188.8.131.52 Empirical rules for estimating a factor of safety 184.108.40.206 Terzaghi and Peck (1948) 220.127.116.11 Sellmeijer and co-workers at Deltares method 18.104.22.168 Schmertmann method 8.4.4 Some field observations 8.4.5 Suggested approach to design for and assessing backward erosion piping 8.4.6 Guidance on whether the overlying soil will form a roof to the pipe 8.4.7 Methods for prediction of initiation and progression of global backward erosion 8.5 Suffusion of internally unstable soils 8.5.1 General description of suffusion 8.5.2 Methods of identifying soils which are internally unstable and potentially subject to suffusion 22.214.171.124 General requirements 126.96.36.199 Some methods for assessing whether a soil is internally unstable 188.8.131.52 Some general comments 8.5.3 Assessment of the gradation after suffusion 8.5.4 Assessment of the seepage gradient which will cause suffusion 8.5.5 Some general comments 184.108.40.206 Need for project specific laboratory tests 220.127.116.11 Do not use "average'' soil gradations 18.104.22.168 Allow for the effects of segregation when assessing suffusion 8.6 Contact erosion 8.6.1 General description of contact erosion 8.6.2 Methods for predicting initiation and progression of contact erosion 22.214.171.124 Non plastic sand below a coarse soil layer 126.96.36.199 Non plastic silt and clay (particles <75Î¼m) below a coarse layer 188.8.131.52 Non-plastic silt above a coarse soil layer 184.108.40.206 General comment 8.6.3 Contact erosion or scour of the dam core into open joints in rock in the foundation 8.7 Continuation and filter action 8.8 Progression of erosion 8.8.1 General description 8.8.2 Overall approach for assessing progression for concentrated leak erosion 8.8.3 Assessing whether the soil will hold a roof to a developing pipe 8.8.4 Assessing whether crack filling action will occur 220.127.116.11 Internal erosion in the embankment 18.104.22.168 Internal erosion through the foundation 22.214.171.124 Internal erosion of the embankment into or at the foundation 8.8.5 Assessing whether upstream flow limitation will occur 8.8.6 Assessing the rate of development of the pipe 8.9 Detection of internal erosion and piping 8.9.1 General principles 8.9.2 Some information on the rate of internal erosion and piping 8.9.3 The likelihood of detection and intervention 8.10 Intervention and repair 8.11 Initiation of breach 8.11.1 General principles 8.11.2 Breach by gross enlargement 8.11.3 Breach by slope instability 8.11.4 Breach by unravelling or sloughing 8.11.5 Breach by sinkhole development leading to loss of freeboard 8.12 Assessment of the likelihood of internal erosion and piping in existing dams 8.12.1 General procedure 8.12.2 The importance of having complete and reliable information upon which to make the assessment of internal erosion 126.96.36.199 Geometric model 188.8.131.52 Geological model of the foundation 184.108.40.206 Geotechnical model of the embankment and foundations 220.127.116.11 Hydraulic or seepage model 18.104.22.168 Stress state in the dam and its foundation 22.214.171.124 General comments 8.12.3 Loading conditions 126.96.36.199 Reservoir level loading 188.8.131.52 Earthquake loading 8.12.4 Potential Failure Modes Analysis (PFMA) 8.12.5 Screening of potential failure modes 184.108.40.206 Screening of PFM on the zoning of the dam and the properties of the core of the embankment 220.127.116.11 Screening of PFM on foundation geology and properties 18.104.22.168 Screening of PFM on details of the embankment foundation geometry, compaction of the core, and conduits and retaining walls 8.12.6 Estimation of likelihoods of failure for the Potential Failure Modes applicable to the dam 22.214.171.124 Some general principles 126.96.36.199 Summary of how to estimate conditional probabilities within the event tree 188.8.131.52 Ways in which the safety of the dam against internal erosion and piping can be considered 184.108.40.206 Quantitative risk analysis methods for internal erosion and piping 9 Design, specification and construction of filters 9.1 General requirements for design and the function of filters 9.1.1 Functional requirements 9.1.2 Flow conditions acting on filters 9.1.3 Critical and non critical filters 9.1.4 Filter design notation and concepts 220.127.116.11 Notation 18.104.22.168 Filtering concepts 22.214.171.124 Laboratory test equipment 9.2 Design of critical and non-critical filters 9.2.1 Particle size based methods for designing no erosion filters with flow normal to the filter 126.96.36.199 Original USBR method 188.8.131.52 Sherard and Dunnigan method 184.108.40.206 Foster and Fell method 220.127.116.11 Vaughan and Soares method 9.2.2 Methods based on constriction or opening size 9.2.3 Methods based on the permeability of the filter 18.104.22.168 Delgardo and co-workers 22.214.171.124 Vaughan and Soares, Vaughan and Bridle method 9.2.4 Recommended method for design of critical no erosion filters, with flow normal to the filter 9.2.5 Recommended method for design of less critical and non-critical filters 126.96.36.199 Filters upstream of the dam core 188.8.131.52 Filters under rip-rap 9.2.6 Review of available methods for designing filters with flow parallel to the filter 9.2.7 Design criteria for pipe drains and pressure relief well screens 184.108.40.206 Pipe drains 220.127.116.11 Pressure relief well screens 9.2.8 Other factors affecting filter design and performance 18.104.22.168 Criteria to assess internal instability or suffusion 22.214.171.124 Segregation 126.96.36.199 Ability of the filter to hold a crack 188.8.131.52 Permeability 184.108.40.206 "Blow-out'' or "heave'' of the filter 9.3 Assessing filters and transition zones in existing dams 9.3.1 Some general issues and concepts 9.3.2 Continuing and excessive erosion criteria 9.3.3 Discussion of continuation scenarios in existing dams 220.127.116.11 Internal erosion in the embankment, from the embankment into the foundation or into openings in conduits passing through the embankment 18.104.22.168 Internal erosion in the foundation 22.214.171.124 Internal erosion of the embankment at or into the foundation 9.3.4 Assessment of the likelihood of continuation where a filter/transition zone does not satisfy no-erosion filter criteria 126.96.36.199 General principles 188.8.131.52 Details of how to apply the Foster and Fell (1999a, 2001) method for assessing the likelihood of continuation of erosion for filters and transitions which do not meet modern filter design criteria 9.3.5 Assessment of the likelihood of continuation for internal erosion into an open defect, joint or crack in the foundation, in a wall or conduit 9.4 Specification of particle size and durability of filters 9.4.1 Particle size distribution 9.4.2 Durability 184.108.40.206 Standard tests for durability and particle shape 220.127.116.11 Possible effects if carbonate rocks are used as filter materials 18.104.22.168 Effects if rocks containing sulphide minerals are used as filter materials 22.214.171.124 Other investigations for filter materials 9.4.3 Contractual difficulties associated with gradation and durability of filters 126.96.36.199 Fines content 188.8.131.52 Use of crushed rock for fine filters 9.5 Dimensions, placement and compaction of filters 9.5.1 Dimensions and method of placement of filters 184.108.40.206 Some general principles 220.127.116.11 Placement methods 9.5.2 Sequence of placement of filters and control of placement width and thickness 9.5.3 Compaction of filters 9.6 Use of geotextiles as filters in dams 9.6.1 Types and properties of geotextiles 9.6.2 Geotextile filter design criteria 18.104.22.168 General requirements 22.214.171.124 Filtering requirement 126.96.36.199 Clogging and blinding resistance 188.8.131.52 Permeability requirement 184.108.40.206 Durability or "survivability'' requirement 220.127.116.11 Use of geotextile filters in dams 18.104.22.168 Construction factors 22.214.171.124 Sources of detailed information 10 Embankment dams, their zoning and design for control of seepage and internal erosion and piping 10.1 Historic performance of embankment dams and the lessons to be learned 10.2 Types of embankment dams, their advantages and limitations 10.2.1 The main types of embankment dams and zoning 10.2.2 The general principles of control of seepage pore pressures and internal erosion and piping 10.2.3 Taking account of the likelihood and consequences of failure in selecting the type of embankment 10.2.4 Types of embankment dams, their advantages, limitations and applicability 10.3 Zoning of embankment dams and typical construction materials 10.3.1 General principles 10.3.2 Examples of embankment designs 10.3.2.1 Zoned earthfill dams 10.3.2.2 Earthfill dams with horizontal and vertical drains 10.3.2.3 Central core earth and rockfill dams 10.3.2.4 Sloping upstream core earth and rockfill dam 10.3.2.5 Concrete face rockfill dams 10.4 Selection of embankment type 10.4.1 Availability of construction materials 10.4.1.1 Earthfill 10.4.1.2 Rockfill 10.4.1.3 Filters and filter drains 10.4.2 Foundation conditions 10.4.3 Climate 10.4.4 Topography and relation to other structures 10.4.5 Saddle dam 10.4.6 Staged construction 10.4.7 Time for construction 10.5 General requirements and methods of control of seepage and internal erosion and piping in embankment dams and their foundations 10.6 Some particular features of rock and soil foundations which affect seepage and internal erosion control 10.7 Details of some measures for pore pressure and seepage flow control 10.7.1 Horizontal and vertical drains in the embankment 10.7.2 Treatment of the sides of the cutoff trench 10.7.3 Prevention of critical seepage gradients and heave of the foundation 10.7.4 Design of pressure relief wells 10.8 Control of foundation seepage and internal erosion and piping by cutoffs 10.8.1 General effectiveness of cutoffs 10.8.2 Cutoff trench 10.8.3 Slurry trench cutoff backfilled with bentonite-sand-gravel 10.8.4 Grout diaphragm wall 10.8.5 Diaphragm wall using rigid or plastic concrete 10.8.6 Methods of excavation of diaphragm walls 10.8.7 Permeability and performance of cutoff walls 10.8.8 We live in a three dimensional world 10.9 Examples of dam upgrades to address deficiencies in internal erosion and piping control 10.9.1 Upgrades to reduce the likelihood of continuation of erosion by providing filters and cutoffs 10.9.2 Upgrades to reduce the likelihood of breach 11 Analysis of stability and deformations 11.1 Analysis of stability and deformations methods of analysis 11.2 Limit equilibrium analysis methods 11.2.1 General characteristics 11.2.2 Some common problems 11.2.3 Three dimensional analysis 11.2.4 Shear strength of partially saturated soils 11.3 Selection of shear strength for design 11.3.1 Drained, effective stress parameters 126.96.36.199 Peak, residual or fully softened strength in clay soils? 188.8.131.52 Selection of design parameters in clay soils 184.108.40.206 Selection of design parameters - granular soils and rockfill 11.3.2 Undrained, total stress parameters 220.127.116.11 Triaxial compression, extension or direct simple shear strength 18.104.22.168 Selection of design parameters 11.3.3 Inherent soil variability 11.4 Estimation of pore pressures and selection of strengths for steady state, construction and drawdown conditions 11.4.1 Steady state seepage condition 22.214.171.124 Steady state pore pressures 126.96.36.199 Pore pressures under flood conditions 11.4.2 Pore pressures during construction and analysis of stability at the end of construction 188.8.131.52 Some general principles 184.108.40.206 Estimation of construction pore pressures by Skempton (1954) method 220.127.116.11 Estimation of construction pore pressures from drained and specified undrained strengths 18.104.22.168 Estimation of pore pressures using advanced theory of partially saturated soil 22.214.171.124 Undrained strength analysis 126.96.36.199 Summing up 11.4.3 Drawdown pore pressures and the analysis of stability under drawdown conditions 188.8.131.52 Some general issues 184.108.40.206 Estimation of drawdown pore pressures, excluding the effects of shear-induced pore pressures 220.127.116.11 Methods for assessment of the stability under drawdown conditions 18.104.22.168 Some detailed issues for drawdown analyses 11.5 Design acceptance criteria 11.5.1 Acceptable factors of safety 11.5.2 Post failure deformation assessment 11.6 Examples of unusual issues in analysis of stability 11.6.1 Hume No. 1 Embankment 11.6.2 Eppalock Dam 11.6.3 The lessons learnt 11.7 Analysis of deformations 11.7.1 Analyses of embankment cross sections 11.7.2 Cross valley deformation analyses 11.8 Probabilistic analysis of the stability of slopes 12 Design of embankment dams to withstand earthquakes 12.1 Effect of earthquake on embankment dams 12.2 Earthquakes and their characteristics 12.2.1 Earthquake mechanisms and ground motion 12.2.2 Earthquake magnitude and intensity 12.2.3 Attenuation and amplification of ground motion 12.2.4 Earthquakes induced by the reservoir 12.3 Evaluation of seismic hazard 12.3.1 Terminology 12.3.2 General principles of seismic hazard assessment 22.214.171.124 Probabilistic approach 126.96.36.199 Seismic hazard from known active or capable faults 12.3.3 Other forms of expression of seismic hazard 12.3.4 Selection of design seismic loading 188.8.131.52 Deterministic approach 184.108.40.206 Risk based approach 220.127.116.11 Which approach to use? 12.3.5 Modelling vertical ground motions 12.3.6 The need to get good seismological advice 12.4 Principles of risk based analyses for earthquake loads 12.4.1 General principles 12.4.2 Failure by loss of freeboard and overtopping 12.4.3 Failure by cracking and internal erosion and piping 12.5 Liquefaction of dam embankments and foundations 12.5.1 Definitions and the mechanics of liquefaction 18.104.22.168 Definitions 22.214.171.124 Some consideration of the mechanics of liquefaction of granular soils 126.96.36.199 Suggested flow chart for evaluation of soil liquefaction 12.5.2 Soils susceptible to liquefaction 188.8.131.52 Methods based on soil classification and in situ moisture content 184.108.40.206 Discussion and recommended approach 220.127.116.11 Methods based on geology and age of the deposit 12.5.3 The "simplified procedure'' for assessing liquefaction resistance of a soil 18.104.22.168 Background to the simplified method 22.214.171.124 Discussion of differences between the Youd et al. (2001), Seed et al. (2003) and Idriss and Boulanger (2008) methods 126.96.36.199 The simplified method - outline 188.8.131.52 Evaluation of Cyclic Stress Ratio (CSR) 184.108.40.206 Evaluation of Cyclic Resistance Ratio for M7.5 earthquakes (CRR7.5) from the Standard Penetration Tests using the Boulanger and Idriss (2012), Idriss and Boulanger (2008) method 220.127.116.11 Evaluation of the Cyclic Resistance Ratio for M7.5 earthquake (CRR7.5) from Cone Penetration Tests using the Idriss and Boulanger (2008) method 18.104.22.168 Evaluation of Cyclic Resistance Ratio for M7.5 earthquake (CRR7.5) from shear wave velocity using the Andrus and Stokoe (2000) method 22.214.171.124 Earthquake magnitude scaling factors and factor of safety against liquefaction 126.96.36.199 Corrections for overburden stress and static shear stress 188.8.131.52 Allowance for the age of the soil deposit 12.6 Liquefied undrained shear strength and post earthquake stability analysis 12.6.1 Some general principles 12.6.2 Background to the assessment of the liquefied shear strength Su(LIQ) 12.6.3 Some methods for assessing the strength of liquefied soils in the embankment and foundation 184.108.40.206 "Critical State'' based methods 220.127.116.11 Normalized strength ratio methods 18.104.22.168 Other methods 12.6.4 Some other factors to consider 12.6.5 Recommended approach to assessing the liquefied undrained strength soils of in the embankment and foundation 12.6.6 Methods for assessing the post earthquake strength of non-liquefied soils in the embankment and foundation 22.214.171.124 Saturated potentially liquefiable soils 126.96.36.199 Cyclic softening in clays and plastic silts 188.8.131.52 Compacted plastic and non-plastic soils 12.6.7 Liquefaction potential and limit equilibrium stability analysis 12.6.8 Site investigations requirements and development of geotechnical model of the foundation 12.7 Seismic deformation analysis of embankment dams 12.7.1 Preamble 12.7.2 Performance of embankment dams during earthquakes 12.7.3 The methods available and when to use them 12.7.4 Suggested approach to estimation of deformations 12.7.5 Screening methods 184.108.40.206 USACE method 220.127.116.11 Hynes-Griffin and Franklin (1984) pseudo-static seismic coefficient method 12.7.6 Empirical database methods 18.104.22.168 Swaisgood (1998, 2003) empirical method for estimating crest settlements 22.214.171.124 Pells and Fell empirical method for estimating settlement, damage and cracking 12.7.7 Simplified methods of deformation analysis for dams where liquefaction and significant strain weakening do not occur 126.96.36.199 General principles 188.8.131.52 Makdisi and Seed (1978) method 184.108.40.206 Bray and Travasarou (2007) method 12.7.8 Advanced numerical methods for estimating deformations during and post earthquake for non-liquefied and liquefied conditions 220.127.116.11 Total stress codes 18.104.22.168 Effective stress codes 22.214.171.124 Summary 12.8 Defensive design principles for embankment dams 12.9 Methods for upgrading embankment dams for seismic loads 12.9.1 General approaches 12.9.2 Upgrading of embankment dams not subject to liquefaction 12.9.3 Embankment dams subject to liquefaction 13 Embankment dam details 13.1 Freeboard 13.1.1 Definitions and overall requirements 13.1.2 Examples of freeboard requirements 126.96.36.199 New embankment dams 188.8.131.52 Existing embankment dams 184.108.40.206 Suggested approach for determining freeboard 13.1.3 Estimation of wave run up freeboard for design of small dams and for feasibility and preliminary design 13.1.4 Estimation of wind setup and wave run-up for detailed design 220.127.116.11 Fetch 18.104.22.168 Design wind 22.214.171.124 Wave height 126.96.36.199 Wave length and wave period 188.8.131.52 Wave run-up 184.108.40.206 Wind set-up 13.2 Slope protection 13.2.1 Upstream slope protection 220.127.116.11 General requirements 18.104.22.168 Sizing and layer thickness 22.214.171.124 Selection of design wind speed and acceptable damage 126.96.36.199 Rock quality and quarrying 188.8.131.52 Design of filters under rip-rap 184.108.40.206 Use of soil cement and shotcrete for upstream slope protection 13.2.2 Downstream slope protection 220.127.116.11 General requirements 18.104.22.168 Grass and rockfill cover 13.3 Embankment crest details 13.3.1 Camber 13.3.2 Crest width 13.3.3 Curvature of crest in plan 13.4 Embankment dimensioning and tolerances 13.4.1 Dimensioning 13.4.2 Tolerances 13.5 Conduits through embankments 13.5.1 Piping into the conduit 13.5.2 Piping along and above the conduit 13.5.3 Flow out of the conduit 13.5.4 Conclusions 13.5.5 Recommendations 13.6 Interface between earthfill and concrete structures 13.6.1 Interface between retaining walls and embankment 13.6.2 Interface between concrete gravity dam and embankment 13.7 Flood control structures 13.8 Design of dams for overtopping during construction 13.8.1 General design concepts 13.8.2 Types of steel mesh reinforcement 13.8.3 Design of steel reinforcement 13.9 Design of rip rap for minor overtopping of levees or small dams during floods 13.10 Other overtopping protection methods for embankment dams 14 Specification and quality control of earthfill and rockfill 14.1 Specification of rockfill 14.2 Specification of earthfill 14.3 Specification of filters 14.4 Quality control 14.4.1 General 14.4.2 `Methods,' and `performance' criteria 14.4.3 Quality control 14.4.4 Influence of non technical factors on the quality of embankment dams 14.5 Testing of rockfill 14.5.1 Particle size, density and permeability 14.5.2 Field rolling trials 14.6 Testing of earthfill 14.6.1 Compaction-test methods 14.6.2 Compaction control - some common problems 14.6.3 Compaction control - some other methods 15 Concrete face rockfill dams 15.1 General arrangement and reasons for selecting this type of dam 15.1.1 Historic development of concrete face rockfill dams 15.1.2 General arrangement - modern practice 15.1.3 Site suitability, and advantages of concrete face rockfill dams 15.2 Rockfill zones and their properties 15.2.1 Zone 2D - Transition rockfill 15.2.2 Zones 2E, 3A and 3B - Fine rockfill, rockfill and coarse rockfill 22.214.171.124 General requirements 126.96.36.199 Layer thickness and compaction 188.8.131.52 Use of gravel as rockfill 15.2.3 Effect of rock properties, compaction and addition of water during compaction on modulus of rockfill 15.2.4 Estimation of the modulus of rockfill 184.108.40.206 Estimation of the secant modulus Erc 220.127.116.11 Estimation of the first filling `pseudo modulus' Erf 18.104.22.168 Effect of valley shape 15.2.5 Selection of side slopes and analysis of slope stability 15.3 Concrete face 15.3.1 Plinth 15.3.2 Face slab 22.214.171.124 Face slab thickness 126.96.36.199 Reinforcement 188.8.131.52 Vertical and horizontal joints 15.3.3 Perimetric joint 184.108.40.206 General requirements220.127.116.11 Water stop details 15.3.4 Crest detail 15.4 Construction aspects 15.4.1 Plinth construction and special details 15.4.2 River diversion 15.4.3 Embankment construction 15.5 Some non-standard design features 15.5.1 Use of dirty rockfill 15.5.2 Dams on erodible foundation 15.5.3 Leaving alluvium in the dam foundation 15.5.4 Plinth gallery 15.5.5 Earthfill cover over the face slab 15.5.6 Spillway over the dam crest 15.6 Observed settlements, and displacements of the face slab, and joints 15.6.1 General behaviour 15.6.2 Post construction crest settlement 15.6.3 Face slab displacements and cracking 15.6.4 Cracks in CFRD dams 15.7 Observed leakage of CFRD 15.7.1 Modern CFRD 15.7.2 Early CFRD and other dams which experienced large leakage 15.8 Framework for assessing the likelihood of failure of CFRD 15.8.1 Overview of approach 15.8.2 Assessment of likelihood of initiation of a concentrated leak 15.8.3 Assessment of the likelihood of continuation of a concentrated leak 15.8.4 Assessment of the likelihood of progression to form a pipe 15.8.5 Assessment of the likelihood of a breach forming 15.8.6 Concluding remarks 15.9 Further reading 16 Concrete gravity dams and their foundations 16.1 Outline of this chapter 16.2 Analysis of the stability for normal operating and flood loads 16.2.1 Design loads 16.2.2 Load combinations 16.2.3 Kinematically feasible failure models 16.2.4 Analysis of stability 16.2.5 Acceptance criteria 16.3 Strength and compressibility of rock foundations 16.3.1 Some general principles 16.3.2 Assessment of rock shear strength 18.104.22.168 General requirements 22.214.171.124 Shear strength of clean discontinuities 126.96.36.199 Shear strength of infilled joints and seams showing evidence of previous displacement 188.8.131.52 Shear strength of thick infilled joints, seams or extremely weathered beds with no previous displacement 184.108.40.206 Shear strength of jointed rock masses with no persistent discontinuities 16.3.3 Tensile strength of rock foundations 16.3.4 Compressibility of jointed rock foundation 16.3.5 Ultimate bearing capacity of rock foundations 16.4 Strength of the concrete in the dam 16.4.1 What is recommended in guidelines 16.4.2 Measured concrete strengths from some USA dams 220.127.116.11 Background to the data 18.104.22.168 Tensile strength of concrete and lift joints 22.214.171.124 Shear strength of concrete 16.5 Strength of the concrete - rock contact 16.6 Uplift in the dam foundation and within the dam 16.6.1 What is recommended in guidelines? 16.6.2 Some additional information on uplift pressures 126.96.36.199 Effects of geological features and deformations on foundation uplift pressures 188.8.131.52 Analysis of EPRI (1992) uplift data 184.108.40.206 Design of drains 220.127.116.11 Hydro-dynamic forces 18.104.22.168 Aprons 22.214.171.124 `Contact' or `box' drains 16.7 Silt load 16.8 Ice load 16.9 The design and analysis of gravity dams for earthquake loading 16.9.1 Introduction 16.9.2 Gravity dams on soil foundations 16.9.3 Gravity dams on rock foundations 126.96.36.199 General 188.8.131.52 The Westergaard pseudo-static method 184.108.40.206 The Fenves-Chopra refined pseudo-static method 220.127.116.11 The US Corps of engineers method 18.104.22.168 Finite Element Method (FEM) 22.214.171.124 Design earthquake input motion 126.96.36.199 Should vertical ground motion be included? 188.8.131.52 Reservoir level variation 184.108.40.206 What do the results of analyses mean? 220.127.116.11 Post-earthquake analyses 18.104.22.168 Dams on rock foundations with potentially deep-seated failure mechanisms 22.214.171.124 Dams on foundations that could be subjected to ground displacement 16.9.4 Concluding remarks 17 Foundation preparation and cleanup for embankment and concrete dams 17.1 General requirements 17.1.1 Embankment dams 17.1.2 Concrete dams 17.1.3 Definition of foundation requirements in geotechnical terms 17.2 General foundation preparation for embankment dams 17.2.1 General foundation under earthfill 126.96.36.199 Rock foundation 188.8.131.52 Soil foundation 17.2.2 General foundation under rockfill 17.2.3 General foundation under horizontal filter drains 17.3 Cutoff foundation for embankment dams 17.3.1 The overall objectives 17.3.2 Cutoff in rock 17.3.3 Cutoff in soil 17.4 Width and batter slopes for cutoff in embankment dams 17.4.1 Cutoff width W 17.4.2 Batter slope 17.4.3 Setting out 17.5 Selection of cutoff foundation criteria for embankment dams 17.6 Slope modification and seam treatment for embankment dams 17.6.1 Slope modification 17.6.2 Seam treatment 17.6.3 Dental concrete, pneumatically applied mortar, and slush concrete 17.6.4 The need for good records of foundation treatment 17.7 Assessment of existing embankment dams 17.8 Foundation preparation for concrete gravity dams on rock foundations 17.8.1 The general requirements 17.8.2 Excavation to expose a suitable rock foundation 17.8.3 Treatment of particular features 17.8.4 Treatment at sites formed by highly stressed rock 18 Foundation grouting 18.1 General concepts of grouting dam foundations 18.2 Grouting design - cement grout 18.2.1 Staging of grouting 18.2.2 The principles of `closure' 18.2.3 The design and quality control of cement grouts 184.108.40.206 The cement and additives used for grouting 220.127.116.11 Water cement ratio 18.104.22.168 Rheological properties of grout 22.214.171.124 High, medium and low mobility grouts 126.96.36.199 Field quality control testing of grouts 188.8.131.52 Grout pressure 184.108.40.206 Recommended closure criteria for embankment and concrete dams18.2.4 Effect of cement particle size, viscosity, fracture spacing and Lugeon value on the effectiveness of grouting 18.2.5 The effectiveness of a grout curtain in reducing seepage 18.2.6 The depth and lateral extent of grouting 18.2.7 Grout hole position and orientation 118.3 Some practical aspects of grouting with cement 18.3.1 Grout holes 18.3.2 Standpipes 18.3.3 Grout caps 18.3.4 Grout mixers, agitator pumps and other equipment 18.3.5 Monitoring of grouting program 18.3.6 Water pressure testing 18.4 Prediction of grout takes 18.5 Durability of cement grout curtains 18.6 Chemical grouts in dam engineering 18.6.1 Types of chemical grouts and their properties18.6.2 Grout penetrability in soil and rock 18.6.3 Grouting technique 18.6.4 Applications to dam engineering 19 Mine and industrial tailings dams 19.1 General 19.2 Tailings and their properties 19.2.1 What are mine tailings? 19.2.2 Tailings terminology and definitions 19.2.3 Tailings properties 220.127.116.11 General 18.104.22.168 Particle size 22.214.171.124 Mineralogy 126.96.36.199 Dry density and void ratio 188.8.131.52 Permeability 184.108.40.206 Properties of water in tailings 19.3 Methods of tailings discharge and water recovery 19.3.1 Tailings discharge 19.3.2 Cyclones 19.3.3 Sub-aqueous vs sub-aerial deposition 19.3.4 Water Recovery 19.4 Prediction of tailings properties 19.4.1 Beach slopes and slopes below water 19.4.2 Particle sorting 19.4.3 Permeability 19.4.4 Dry density 19.4.5 The prediction of desiccation rates 19.4.6 Drained and undrained shear strength 220.127.116.11 Drained shear strength 18.104.22.168 Undrained shear strength 19.5 Methods of construction of tailings dams 19.5.1 General 19.5.2 Construction using tailings 22.214.171.124 Upstream method 126.96.36.199 Downstream method 188.8.131.52 Centreline method19.5.3 Construction using conventional water dams19.5.4 Selection of embankment construction method 19.5.5 Control of seepage by tailings placement, blanket drains and under-drains 184.108.40.206 Tailings placement 220.127.116.11 Drainage blankets and under-drains 19.5.6 Some factors affecting the potential for internal erosion and piping of tailings dams 19.5.7 Some factors to consider for seismic design of tailings dams 18.104.22.168 Conventional dams and downstream construction 22.214.171.124 Upstream construction 19.5.8 Storage layout 19.5.9 Other disposal methods 126.96.36.199 Thickened discharge or Robinsky method 188.8.131.52 Co-disposal 184.108.40.206 Paste disposal 220.127.116.11 Belt filtration18.104.22.168 Disposal into open cut and underground mine workings 22.214.171.124 Discharge into rivers or the sea 19.6 Seepage from tailings dams and its control 19.6.1 General 19.6.2 Principles of seepage flow and estimation 19.6.3 Some common errors in seepage analysis 19.6.4 Seepage control measures 126.96.36.199 Controlled placement of tailings 188.8.131.52 Foundation grouting 184.108.40.206 Foundation cutoffs 220.127.116.11 Clay liners 18.104.22.168 Under-drains 22.214.171.124 Synthetic liners (geomembranes) 126.96.36.199 Geomembrane liners 19.6.5 Seepage collection and dilution measures 188.8.131.52 Toe drains 184.108.40.206 Pump wells 220.127.116.11 Seepage collection and dilution dams 19.6.6 Rehabilitation 18.104.22.168 Long term stability and settlement 22.214.171.124 Erosion control 126.96.36.199 Seepage control 188.8.131.52 Return of area to productive use 20 Monitoring and surveillance of embankment dams 20.1 What is monitoring and surveillance? 20.2 Why undertake monitoring and surveillance? 20.2.1 The objectives 20.2.2 Is it really necessary? 20.2.3 Some additional information on embankment dam failures and incidents 20.2.4 Time for development of internal erosion and piping failure of embankment dams and ease of detection 20.2.5 The ability of monitoring to detect slope instability 20.3 What inspections and monitoring is required? 20.3.1 General principles 20.3.2 Some examples of well instrumented embankment dams 20.3.3 Dam safety inspections 20.4 How is the monitoring done? 20.4.1 General principles 20.4.2 Seepage flow measurement and observation 20.4.3 Surface displacements 20.4.4 Pore pressures 184.108.40.206 Why and where are pore pressures measured? 20.4.5 Pore air and pore water pressure 220.127.116.11 Fluctuations of pore pressure with time and the lag in response of instruments 18.104.22.168 Types of instruments and their characteristics 20.4.6 Should piezometers be installed in the cores of earth and earth and rockfill dams? 20.4.7 Displacements and deformation 22.214.171.124 Vertical displacements and deformation 126.96.36.199 Horizontal displacements and deformations 20.4.8 Thermal monitoring of seepage 188.8.131.52 General 184.108.40.206 Distributed fibre optic temperature sensing 220.127.116.11 Thermotic sensors in stand pipes in the dam 18.104.22.168 Infra-red imaging of the downstream face of the dam and foundations 20.4.9 Use of geophysical methods to detect seepage 22.214.171.124 Self potential 126.96.36.199 Resistivity 188.8.131.52 Other methods ReferencesAppendix A: Methods for estimating the probability of failure by internal erosion and piping Subject index
About the Author
Robin Fell is Emeritus Professor of Civil Engineering at the University of New South Wales, Australia, and also works as a consultant. He has more than 40 years of experience in geotechnical engineering of dams, landslides and civil and mining projects in Australia and Asia. He has worked on over 100 dams worldwide and has been involved in all aspects of planning, site investigation, design and construction of embankment dams. Patrick MacGregor is a Consulting Engineering Geologist with more than 40 years experience in the assessment of geological constraints for major civil engineering projects in a number of countries. He has been involved in dam investigation, design and construction, and particularly worked on hydroelectric developments at all stages from inception to operation. David Stapledon spent many years investigating large dam construction sites in various countries. He was a Professor of Engineering Geology at the University of South Australia (1964 -1993) and worked as a Consultant in Engineering Geology, contributing to major dam projects in Australia, New Zealand and South East Asia. He has more than 50 years of experience and was awarded the John Jaeger Memorial Medal for Contributions to Geomechanics in 1995. Graeme Bell has been a Consulting Dam Engineer since 1962. His role has varied from providing the full technical input, design management and construction advice for new dams to the preparation of complex structural analyses of existing dams. From 1979, he has acted as an independent reviewer on many dam projects, mainly in Australia, but also in several overseas locations. Mark Foster has 20 years of experience in dam engineering and geotechnical engineering. This has involved a wide variety of projects including dam safety reviews, design of dam upgrade projects and dam safety risk assessments for embankment and concrete dams. He has a particular interest in the assessment of piping and internal erosion of embankment dams which was the topic of his doctoral research studies at the University of New South Wales.
Eleven years after the publication of the first edition of the excellent book Geotechnical Engineering of Dams, the geotechnical and dam engineering community can enjoy reading and analyzing the second edition, completely revised, updated, enlarged and enriched. [...] All chapters are almost equally important and interesting for any dam and geotechnical engineer, but I especially like chapters 8 and 9, dealing with internal erosion, piping and filters at embankment dams and in foundation. Apparently, a great experience and original research knowledge of part of the authors of the book is embedded in these thoroughly executed chapters. I cannot also avoid mentioning chapter 12 - Design of embankment dams to withstand earthquakes - in which an up-to-date review and analysis of this sensitive aspect of embankment dam design is given, still under intensive development.Dam builders have always been aware of the fact that dams are firmly bonded to the foundation. But, with this extraordinary book, the bond seems even stronger! I am sure this book will be an unavoidable professional reference and guide in the libraries of all dam and geotechnical engineers. Also, I strongly recommend the book to advanced university students as a textbook, as well as a source of ideas for further research works. Ljubomir Tanchev, Professor on dams and hydraulic structures, University of Skopje, Macedonia This book fills a lacuna in the available comprehensive literature on Geotechnical Engineering of Dams. [...] It covers dimensions not seen in normally available and commonly prescribed textbooks. An intuitive sense of amalgamating both theory and practice is the distinguished and remarkable feature of the book. [...]A very important and useful aspect of the book is that it covers common errors in the five major aspects of safe dams and provides insight in these aspects by dealing with practical problems and case studies.The book very well covers all important geotechnical aspects of dam engineering for civil engineering students at undergraduate as well as at post graduate level and for practitioners. [...] Academicians & practicing engineers will be able to sharpen their knowledge with the help of input provided by the book. The book is useful to civil engineers [...] working in the area of geotechnical dam engineering and ground improvement. Prof. Gautam N. Gandhi, President, Indian Geotechnical Society, New Delhi, Formerly Principal, IDS, Nirma University, India The book is an excellent contribution in the area of dam engineering. Dam Engineering has become an important area in providing efficient infrastructure for water supply, power generation as well as resources generation and conservation. The revision of the previous edition is timely and up to date. [...] In summary, the treatise is comprehensive, up-to-date and needs to be studied by scientists and engineers, organizations, professional bodies, policy makers and builders connected with dam engineering. Prof. G.L. Sivakumar Babu, Chairman, International Technical Committee on Forensic Geotechnical Engineering ISSMGE / Governor, Region 10, American Society of Civil Engineers, USA / Editor-in Chief, Indian Geotechnical Journal, Department of Civil Engineering, Indian Institute of Science, Bangalore, India
25.15 x 17.53 x 6.35 centimetres (1.95 kg)|
15+ years |