DAMS AND APPURTENANT HYDRAULIC STRUCTURES

Transcription

1 rs-t DAMS AND APPURTENANT HYDRAULIC STRUCTURES LJUBOMIR TANCEV Professor, Faculty of Civil Engineering, Sts Cyril and Methodius University, Skopje, Republic of Macedonia A.A. BALKEMA PUBLISHERS LEIDEN / LONDON / NEW YORK / PHILADELPHIA / SINGAPORE

2 Contents Preface xiii PART ONE: DAMS AND APPURTENANT HYDRAULIC 1 STRUCTURES - GENERAL 1 UTILIZATION OF WATER RESOURCES BY MEANS OF HYDRAULIC 3 STRUCTURES 1.1 Introduction Hydraulic structures (definition, classification) General features of hydraulic structures Intent of dams. Elements of a dam and a reservoir Short review of the historical development of hydraulic structures 17 2 FOUNDATIONS OF DAMS Foundations for hydraulic structures in general Requirements for the foundation Investigation works regarding dam foundations Improvement of foundations 32 3 SEEPAGE THROUGH DAMS Action of seepage flow Mechanical action of seepage flow on the earth's skeleton Seepage resistance of earth foundations and structures Theoretical aspects of seepage Practical solution of the problem of seepage Seepage in anisotropic soil conditions Seepage in non-homogeneous soil conditions Seepage of water through rock foundations Lateral seepage Seepage through the body of concrete dams 65 4 FORCES AND LOADINGS ON DAMS Forces and loadings on dams in general Forces from hydrostatic and hydrodynamic pressure Influence of cavitation and aeration on hydraulic structures Influence from waves Influence of ice and water sediment Seismic forces Temperature effects Temperature effects on embankment dams Temperature effects on concrete structures 86

3 vi CONTENTS 5 DESIGNING HYDRAULIC STRUCTURES Basic stages in the process of the creation and use of hydraulic structures Investigation for design and construction of hydraulic structures Contents of the hydraulic design and design phases Project management and the role of legislation 97 PART TWO: EMBANKMENT DAMS EMBANKMENT DAMS - GENERAL Introduction, terminology, and classification Historical development of embankment dams Dimensions of the basic elements of embankment dams Choice of the dam site H5 6.5 Materials for construction of embankment dams Choice of type of embankment dam Tailings dams SEEPAGE THROUGH EMBANKMENT DAMS Kinds of seepage through the embankment dam body Seepage line and hydrodynamic net in embankment dams Measures against the harmful effect of seepage Action against local seepage rising Action against external erosion Calculations of the casual seepage strength of earthfill dams STATIC STABILITY OF EMBANKMENT DAMS Introduction Classical methods Method of slices Wedge method States in which stability of embankment dams is examined Stability of rockfill dams Contemporary methods Application of the Finite Element Method Specific properties of the application of the Finite Element Method 161 (FEM) for analysis of embankment dams Choice of constitutive law Simulation for dam construction in layers Simulation for filling the reservoir and the effect of water Simulation of behavior at the interfaces of different materials Analysis of consolidation Creep of materials in the body of embankment dams Three-dimensional analysis DYNAMIC STABILITY OF EMBANKMENT DAMS Effect of earthquakes on embankment dams Assessment of design earthquake 199

4 CONTENTS VII Strength, attenuation, and amplification of earthquakes Design earthquake Liquefaction Analysis of stability and deformations in embankment dams induced 207 by earthquakes Pseudo-static method Pseudo-static methods with a non-uniform coefficient 209 of acceleration Equivalent linear method Pure nonlinear method EARTHFILL DAMS Classification and construction of earthfill dams Structural details for earthf ill dams Slope protection Water-impermeable elements Drainages Preparation of the foundation and the joint between earthfill dams 243 and the foundation Preparation of the general foundation Preparation of the foundation when using a dam cutoff trench Joint of the earthfill dam and the foundation EARTH-ROCK DAMS Construction of earth-rock dams Earth-rock dams with vertical core Earth-rock dams with a sloping core Earth-rock dams of'soft'rocks Fissures in the core of earth-rock dams Kinds of fissures and causes for their occurrence Measures for preventing the occurrence of fissures Designing earth-rock dams in seismically active areas ROCKFILL DAMS WITH REINFORCED CONCRETE FACING Definition, field of application and construction Modern dams with reinforced concrete facing Joints for reinforced concrete facings Construction of reinforced concrete facings Examples of modern dams with reinforced concrete facing ROCKFILL DAMS WITH ASPHALTIC CONCRETE AND OTHER 303 TYPES OF FACINGS 1 Rockfill dams with asphaltic concrete facing General characteristics Composition and characteristics of hydraulic asphaltic concrete Construction of the asphaltic concrete facings Joint of the lining with a gallery or concrete cutoff in dam's toe Joint of the facing with dam's crest 317

5 viii CONTENTS 2 Rockf ill dams with steel facing 3 Rockfill dams with facing of geomembrane ROCKFILL DAMS WITH DIAPHRAGM WALL Rockfill dams with asphaltic concrete diaphragm wall Function, conditions of work and materials Structure of the asphaltic concrete diaphragm walls Joint of diaphragm wall with the foundation and lateral 335 concrete structures 14.2 Other types of diaphragm walls Concrete diaphragm walls Grout and plastic diaphragm walls Stability of earth-rock dams with diaphragm wall MONITORING AND SURVEILLANCE OF EMBANKMENT DAMS Task and purpose of monitoring Monitoring of pore pressure and seepage Hydraulic piezometers Electric piezometers Monitoring of seepage Monitoring of displacements Measurement of displacements at the surface of the dam Measuring displacements in the interior of the dam Measurements of stresses Seismic measurements General principles on the selection and positioning layout of measuring 368 instruments PART THREE: CONCRETE DAMS GRAVITY DAMS ON ROCK FOUNDATIONS Gravity dams in general Mass concrete for dams General Constituent elements of mass concrete Parameters of concrete mixture Fabrication and placing of concrete Cross-section of gravity dams Cross-sections in general Theoretical cross-section Practical cross-section Dimensioning of concrete gravity dams Elementary methods Modern methods Determination of stresses Determination of stresses by the gravitational method Calculation of stresses by using the theory of elasticity 395 3J8

6 CONTENTS IX Influence of temperature changes, shrinkage and expansion of 397 concrete on stresses in dams Permissible stresses and cracks General structural features of gravity dams Stability of gravity dams on rock foundation Dam sliding and shearing across foundation Hollow gravity dams GRAVITY DAMS ON SOIL FOUNDATIONS Fundamentals of gravity dams on soil foundation Schemes for the underground contour of the dam Determination of basic dimensions of underground contour Construction of elements of the underground contour Construction of the dam's body Dimensioning and stability of gravity dams on soil foundation ROLLER-COMPACTED CONCRETE GRAVITY DAMS Introduction Characteristics of roller-compacted concrete Types of roller-compacted concrete Trends in development of dams made of roller-compacted concrete Improving the water-impermeability of dams made of roller-compacted 448 concrete 18.6 Cost of dams made of roller-compacted concrete Examples of dams made of roller-compacted concrete Particularities of high dams of roller-compacted concrete BUTTRESS DAMS Definition, classification and general conceptions Massive-head buttress dams Flat-slab buttress dams Multiple-arch buttress dams Conditions for application of buttress dams ARCH DAMS Arch dams in general - classification Development of arch dams through the centuries Methods of designing arch dams Basic design Arch dams with double curvature Form of arches in plan and adaptation to ground conditions Structural details of arch dams Static analysis of arch dams Method of independent arches Method of central cantilever The Trial-Load Method 537

7 x CONTENTS The Finite Element Method The Experimental Method DYNAMIC STABILITY OF CONCRETE DAMS Earthquake effects on concrete dams Methods for dynamic analysis of concrete dams Linear analysis and response of the structure Nonlinear analysis and the response of the dam Knowledge gained from practice and experiments MONITORING AND SURVEILLANCE OF CONCRETE DAMS Monitoring, surveillance, and instrumentation of concrete dams general 22.2 Monitoring by precise survey methods Surveillance with embedded instruments Automatization and computerization of monitoring PART FOUR: HYDROMECHANICAL EQUIPMENT AND APPURTENANT 565 HYDRAULIC STRUCTURES 23 MECHANICAL EQUIPMENT AND APPURTENANT 567 HYDRAULIC STRUCTURES - GENERAL 23.1 Hydromechanical equipment - general Introduction Classification of gates and valves Forces acting on gates and valves Mechanisms for lifting and lowering of the gates and valves. Service 569 bridges 23.3 Installation and service of gates and valves Appurtenant hydraulic structures Definition, function, and capacity Classification of spillways and bottom outlets Evacuation of overflowing waters via a chute spillway Energy dissipation of the spillway jet Selection of type of spillway structure SURFACE (CREST) GATES Basic schemes of surface (crest) gates Surface (crest) gates transferring water pressure to side walls or piers Ordinary plain metal gates Special plain gates Stop-log gates Radial gates Roller gates Surface (crest) gates transferring the water pressure to the gate sill Sector (drum) gates Flap gates 613

8 CONTENTS XI Bear-trap gates Inflatable gates HIGH-HEAD GATES AND VALVES General characteristics - classification High-head gates transferring pressure to the structure directly through 621 their supports Plain high-head gates Radial (taintor) high-head gates Diaphragm gate Valves transferring the pressure through the shell encasing the valve Waterworks valve types Disc-like or butterfly valves Cone dispersion valve Needle valves and spherical valves Cylindrical balanced high-head valves SPILLWAYS PASSING THROUGH THE DAM'S BODY Crest spillways High-head spillway structures SPILLWAYS OUTSIDE THE DAM'S BODY Frontal (ogee) spillway structure Side-channel spillway Shaft (morning glory) spillway Siphon spillways BOTTOM OUTLET WORKS Basic assumptions on designing bottom outlet works Bottom outlet works in concrete dams Bottom outlet works in embankment dams SPECIAL HYDRAULIC STRUCTURES Transport structures Hydraulic structures for the admission and protection of fish RIVER DIVERSION DURING THE CONSTRUCTION OF 709 THE HYDRAULIC SCHEME 30.1 River diversion during the construction of dams and appurtenant 709 hydraulic structures - general 30.2 Construction of the structures without river diversion from the parent 710 river channel Method with damming of the construction (foundation) pit Method without damming of the construction pit Construction of the structures with river diversion from the river channel 716

9 XII CONTENTS PART FIVE: HYDRAULIC SCHEMES COMPOSITION OF STRUCTURES IN RIVER HYDRAULIC SCHEMES Definition and classification of hydraulic schemes General conditions and principles for the composition of hydraulic schemes Characteristics of river hydraulic schemes for different water 723 economy branches 31.4 Aesthetic shaping of hydraulic schemes River hydraulic schemes without pressure head Low-head hydraulic schemes Medium-head river hydraulic schemes HYDRAULIC SCHEMES High-head river hydraulic schemes on mountain rivers (Type I) High-head hydraulic schemes on middle and low parts of rivers Pumped-storage hydraulic scheme RESERVOIRS Introduction Formation and safety of reservoirs Stability of reservoir banks Water-impermeability of the reservoir Seismicity ofthe ground in the zone of the reservoir Water absorption ofthe ground in the zone ofthe reservoir Evaporation Sediment accumulation Resettlement of population and relocation of structures Sports and recreational facilities NEGATIVE EFFECTS OF HYDRAULIC SCHEMES AND 775 ENVIRONMENTAL PROTECTION 34.1 Types of negative effects on the environment Changing the land into the area of the reservoir Change of the flow downstream of the dam Damming the migration paths of fish and wild animals Change in the surrounding landscape and the microclimate Social and ecological monitoring Environmental protection - selection of a solution with minimum 783 negative effects on the environment 35 RESTORATION AND RECONSTRUCTION OF HYDRAULIC SCHEMES Need for restoration and reconstruction Restoration of dams and hydraulic schemes Reconstruction of hydraulic schemes 795 References and Abbreviations 803 Subject Index Index of Dams