This document provides information on the analysis, design, behavior, and seismic resistance of concrete face rockfill dams (CFRDs). It discusses numerical modeling of CFRDs, stresses in the concrete face and underlying transition zones, and the effects of high compressibility of rockfill materials. It also summarizes general recommendations for dynamic analysis and design of high CFRDs in seismic regions, including use of roller compacted concrete to reduce concrete face deformation. A new design for the 275m high Kambarata-1 CFRD in Kyrgyzstan incorporates this technique to improve seismic safety.
Lyapichev. Modern structural & technological solutions for new projects of hi...Yury Lyapichev
This document discusses modern structural solutions for large dams, including:
1) New designs for roller-compacted concrete (RCC) dams that improve seismic safety, such as facing symmetrical hardfill (FSH) dams with lean RCC zones and inner rockfill cores.
2) Proposed designs for very tall concrete-faced rockfill (CFR) dams over 100m that decrease cracking risks by including RCC supporting elements under the concrete facing.
3) The Kankunskaya rockfill dam design in Russia that utilizes an asphalt concrete core to improve safety compared to other core types, especially in seismic areas. Case studies and analyses demonstrate the viability of these innovative dam designs.
Lyapichev Yury - Innovation structures of very lean RCC dams (Journal of Stru...Yury Lyapichev
This document discusses innovations in the structural design of roller compacted concrete (RCC) dams to reduce cement consumption and expand their use on non-rock foundations. It analyzes the static and seismic stress-strain states of symmetrical RCC dams with very lean concrete cores. It finds that for rock and dense sandy-gravel foundations, symmetrical RCC dams with slopes of 0.5-0.7 and outer zones of conventional concrete and central zones of cement-strengthened rockfill are the most economical option. These dams can be built up to 200m high on rock foundations and up to 100m high on dense sandy gravel foundations. They have greater seismic resistance and technical/economic efficiency than conventional RCC dams.
This document summarizes tunnelling projects and experiences in Greece from the early 1990s to present. It discusses the Athens Metro and use of microtunnelling and jet grouting to construct underground stations. It also describes the Egnatia Motorway project and challenges with Tunnel S3. Specifically, it examined over 100km of railway tunnels and nearly 350km of motorway and railway tunnels constructed. Lessons included using a Geological Strength Index and Tunnel Stability Factor to assess tunnel conditions. Jet grouting was used to improve weak rock and prevent face collapses during the Athens Metro project.
This document proposes an alternative design for constructing the foundations of a new pedestrian bridge across a harbour. It suggests using a temporary sheet pile wall cofferdam that would allow workers to build the pile group and pile cap at the riverbed level, avoiding the need for divers. The cofferdam design is sized at 10x10m and embedded 10m deep. Calculations are presented to check for piping, heaving, and structural failure. A finite element model is also used. It is determined that drains will be needed to reduce water pressures and piping risks. The design of the internal bracing structure and construction sequence are also considered. The cofferdam is concluded to be a feasible alternative construction method for the bridge
This document discusses the challenges of tunnel design and construction in the GCC (Gulf Cooperation Council) region. It outlines several ongoing and future major tunneling projects in GCC countries like Qatar, Saudi Arabia, and Oman. Key challenges include weak rock formations, karstic features, high groundwater, and tight project timelines. Solutions proposed include using closed-face TBMs, detailed risk analysis to estimate machine advance rates, grouting programs for karst, and steel fiber-reinforced concrete tunnel linings to resist aggressive groundwater. Overall, the large scale of projects in challenging geotechnical conditions requires innovative design and construction approaches.
Practices in Planning, Design and Construction of Head Race Tunnel of a Hydro...Mohit Shukla
This paper has been selected for oral presentation as well as inclusion in the conference proceedings of the ICCCGE 2016 : 18th International Conference on Civil,Construction and Geological Engineering held in Toronto, Canada during June,
13-14, 2016. This paper was also able to find a position in the international conference of Dams and Hydropower held at Laos in May 2016.
Lyapichev. Modern structural & technological solutions for new projects of hi...Yury Lyapichev
This document discusses modern structural solutions for large dams, including:
1) New designs for roller-compacted concrete (RCC) dams that improve seismic safety, such as facing symmetrical hardfill (FSH) dams with lean RCC zones and inner rockfill cores.
2) Proposed designs for very tall concrete-faced rockfill (CFR) dams over 100m that decrease cracking risks by including RCC supporting elements under the concrete facing.
3) The Kankunskaya rockfill dam design in Russia that utilizes an asphalt concrete core to improve safety compared to other core types, especially in seismic areas. Case studies and analyses demonstrate the viability of these innovative dam designs.
Lyapichev Yury - Innovation structures of very lean RCC dams (Journal of Stru...Yury Lyapichev
This document discusses innovations in the structural design of roller compacted concrete (RCC) dams to reduce cement consumption and expand their use on non-rock foundations. It analyzes the static and seismic stress-strain states of symmetrical RCC dams with very lean concrete cores. It finds that for rock and dense sandy-gravel foundations, symmetrical RCC dams with slopes of 0.5-0.7 and outer zones of conventional concrete and central zones of cement-strengthened rockfill are the most economical option. These dams can be built up to 200m high on rock foundations and up to 100m high on dense sandy gravel foundations. They have greater seismic resistance and technical/economic efficiency than conventional RCC dams.
This document summarizes tunnelling projects and experiences in Greece from the early 1990s to present. It discusses the Athens Metro and use of microtunnelling and jet grouting to construct underground stations. It also describes the Egnatia Motorway project and challenges with Tunnel S3. Specifically, it examined over 100km of railway tunnels and nearly 350km of motorway and railway tunnels constructed. Lessons included using a Geological Strength Index and Tunnel Stability Factor to assess tunnel conditions. Jet grouting was used to improve weak rock and prevent face collapses during the Athens Metro project.
This document proposes an alternative design for constructing the foundations of a new pedestrian bridge across a harbour. It suggests using a temporary sheet pile wall cofferdam that would allow workers to build the pile group and pile cap at the riverbed level, avoiding the need for divers. The cofferdam design is sized at 10x10m and embedded 10m deep. Calculations are presented to check for piping, heaving, and structural failure. A finite element model is also used. It is determined that drains will be needed to reduce water pressures and piping risks. The design of the internal bracing structure and construction sequence are also considered. The cofferdam is concluded to be a feasible alternative construction method for the bridge
This document discusses the challenges of tunnel design and construction in the GCC (Gulf Cooperation Council) region. It outlines several ongoing and future major tunneling projects in GCC countries like Qatar, Saudi Arabia, and Oman. Key challenges include weak rock formations, karstic features, high groundwater, and tight project timelines. Solutions proposed include using closed-face TBMs, detailed risk analysis to estimate machine advance rates, grouting programs for karst, and steel fiber-reinforced concrete tunnel linings to resist aggressive groundwater. Overall, the large scale of projects in challenging geotechnical conditions requires innovative design and construction approaches.
Practices in Planning, Design and Construction of Head Race Tunnel of a Hydro...Mohit Shukla
This paper has been selected for oral presentation as well as inclusion in the conference proceedings of the ICCCGE 2016 : 18th International Conference on Civil,Construction and Geological Engineering held in Toronto, Canada during June,
13-14, 2016. This paper was also able to find a position in the international conference of Dams and Hydropower held at Laos in May 2016.
This document provides a summary of the scope of work for engineering design and installation of a new 10-inch, 22 km offshore pipeline from Palang to an FSO unit. The scope includes pipeline design, material selection, coating and cathodic protection design, engineering drawings, installation analysis using specialized software, and environmental and geotechnical data collection. Key deliverables are the wall thickness verification, free span analysis, anode design, and pipeline expansion calculation.
Rcc box culvert methodology and designs including computer methodcoolidiot07
This document discusses the methodology and design of reinforced concrete box culverts. It addresses key considerations for the structural design of box culverts, including:
1) Load cases to consider (empty, full, surcharge loads), factors like live load, effective width, earth pressure, and impact.
2) Methods for determining the coefficient of earth pressure and its effect on design. Values of 0.333 and 0.5 are compared.
3) Determining the effective width to use for live load distribution, which significantly impacts design of culverts without cushion. Different approaches in codes and literature are discussed.
4) The document aims to comprehensively cover design provisions, considerations, and justification of factors impact
This document discusses rock tunnel engineering. It introduces different types of tunnels and their purposes. Tunnels can have various cross-sectional shapes and be located underground in different ground types. Tunnels are constructed using methods like cut-and-cover, drilling and blasting, or mechanized boring machines. Geotechnical investigations for tunnels are challenging due to uncertainties in ground conditions. Rock mass classification systems help characterize rock strength. The principles of tunnel stabilization and design aim to control ground movements rather than carry ground loads by mobilizing the strength of the surrounding ground.
The document provides an overview of the "Cut-and-Cover" and "Cover-and-Cut" tunnel construction techniques. The "Cut-and-Cover" method involves excavating a trench and constructing the tunnel structure within it, then refilling the trench. The "Cover-and-Cut" method first constructs a retaining concrete shell, then excavates underneath it for tunnel construction. Both methods are used for highway and railway tunnels where shallow depths or unstable ground conditions require extra support during construction. The document discusses the design process and construction steps for each method.
Tunnelling is a serious engineering project.
In addition to large investment cost, the challenges related to long and deep tunnels are considerable.
Important aspects which needs to be considered are related to the construction works, geology, environment and operation. his module highlights all these aspects.
The document discusses foundation treatment for dams. It covers treating rock foundations by excavating to solid rock, cleaning rock surfaces, treating defects like seams, and using grouting. It also discusses treating earth foundations to provide bearing strength, prevent sliding and seepage, and protect against piping. Common earth foundation treatments include cutoff walls, impervious blankets, drainage systems, and using piles. The effectiveness of partial versus complete cutoff walls is analyzed.
This document provides an overview of tunneling, including the purposes of tunnels, effects of tunneling on the ground, tunnel lining, economic aspects, geological considerations, overbreak, and examples of important tunnels. Tunnels are used for transportation, utilities, and protection from hazards. They affect the surrounding ground and require lining for structural integrity and waterproofing. Cost, time, and construction method are economic factors to consider. Geological conditions like rock type influence tunnel design and construction challenges like overbreak. The Pir Panjal Railway Tunnel in India is highlighted as a significant tunnel project.
Dams are classified based on their purpose, materials used, and hydraulic design. The main types are embankment dams made of earth or rock, and concrete dams including gravity, buttress, and arch dams. Embankment dams use local natural materials and have lower foundation requirements but greater risks of overtopping. Concrete dams can better withstand overtopping but require stronger foundations and transportation of materials. Both dam types have advantages and disadvantages depending on the site conditions and purposes.
Major issues to be considered for the successful application of unreinforced and steel fiber reinforced concrete (SFRC) tunnel final linings concepts include:
1) Application limits related to the geotechnical environment, seismic regime, and topography that must be determined based on safety and serviceability requirements.
2) Existing design codes and recommendations provide frameworks for evaluating the safety and serviceability of these lining concepts.
3) Case studies demonstrate that unreinforced and SFRC tunnel linings have been successfully used in tunnels up to 8km and 4.8km respectively, in various ground conditions.
This document provides an overview of embankment dam design and construction. It discusses the types of embankment dams, causes of failure, and design procedures. The key points covered are:
1. Types of embankment dams include homogeneous dams with toe drains or blankets, and zoned dams with central cores and filters/blankets.
2. Causes of failure include hydraulic failures from overtopping, seepage failures from piping/leakage, and structural failures from sliding, liquefaction, or settlement.
3. Design considers safety against hydraulic, seepage and structural failures. This includes limiting seepage, ensuring stability of slopes, and providing adequate spillway capacity.
tunnelling scope, construction techniques and necessityShashank Gaurav
This document discusses tunnel construction methods and planning. It describes the main types of tunnels based on application and construction method. The key construction methods covered are cut-and-cover, pipe jacking, shield tunneling, New Austrian tunneling method, and immersed tube tunneling. For each method, the document outlines the construction sequence, advantages, and disadvantages. Proper planning stages including investigations and alignment selection are also emphasized.
This document summarizes the key aspects of box culvert design and analysis. Box culverts consist of horizontal and vertical slabs built monolithically, and are used for bridges with limited stream flows and high embankments up to spans of 4 meters. They are economical due to their rigidity and do not require separate foundations. Design loads include concentrated wheel loads, uniform loads from embankments and decks, sidewall weights, water pressure when full, earth pressures, and lateral loads. The culvert is analyzed for moments, shears, and thrusts using classical methods to determine force effects from these various loading conditions.
Importance of geological considerations while choosing tunnel sites and align...Buddharatna godboley
This document discusses the importance of geological considerations when selecting sites and alignments for tunnels. It notes that geological investigations are essential for choosing the best route, determining the excavation method, designing the tunnel, assessing costs and stability, and evaluating environmental hazards. The document provides details on how different rock types and geological structures like folding and faulting can impact tunnel construction and design. It emphasizes that understanding the area's geology is crucial for planning tunnels and minimizing risks.
Necessity/advantage of a tunnel, Classification of Tunnels,
Size and shape of a tunnel, Alignment of a Tunnel, Portals and Shafts,
Methods of Tunneling in Hard Rock and Soft ground, Mucking, Lighting
and Ventilation in tunnel, Dust control, Drainage of tunnels, Safety in
tunnel construction.
The document discusses the design of an ogee spillway for a concrete gravity dam. It describes how shifting the curve of the nappe spillway profile can save concrete by becoming tangential to the downstream dam face. It then provides sample calculations for designing an ogee spillway based on given parameters like discharge rate, dam dimensions, and river levels. These include calculating the design head, developing the upstream and downstream spillway profiles, and considering factors that affect spillway design.
This document summarizes the key loads and design considerations for concrete dams. It discusses the primary, secondary, and exceptional loads that act on gravity dams, including water load, self-weight, uplift, wave load, silt load, wind load, and earthquake load. It also covers the design of gravity dams against overturning, sliding, and material failure. Buttress and arch dam designs are briefly introduced. Thin cylinder theory for arch dam design is explained.
The document discusses various types of loads and pressures that act on underground tunnels, including:
1) Earth/rock pressures and water pressure are the most important potential loads. Live loads from surface traffic can usually be neglected.
2) Dimensions of tunnel sections must account for overburden weight (geostatic pressure) or loosening pressure (weight of loosened rock zone).
3) Lateral pressures, bottom pressures, and rock pressures are discussed. Several theories for estimating vertical and lateral loads are presented, including those by Bierbaumer, Terzaghi, and Tsimbaryevitch.
4) Rock pressures depend on factors like the quality of rock, stresses/strains around the
- The document provides information about tunnels and tunneling, including background on some of the earliest tunnels constructed by ancient Egyptians and Babylonians.
- Tunnels can be classified based on their purpose, geological location/condition, and cross-sectional shape. Examples of different tunnel types and shapes are given.
- Key geological conditions that influence tunnel planning and construction are discussed, including rock properties, groundwater conditions, and fault zones. The importance of site investigations is emphasized.
- Methods of tunnel construction in soft ground, dealing with water and gases in tunnels, and controlling temperature are outlined. Excavation methods like cut-and-cover, sequential excavation (drill-and-blast), and tunnel boring
Lyapichev. Problems in numerical analysis of CFRDs (ICOLD Bull.155)6 p.)Yury Lyapichev
The document discusses several challenges and developments in numerically analyzing concrete faced rockfill dams (CFRDs). It notes that until recently, CFRDs were designed based on experience rather than analysis. Accurate models have since shown issues like excessive compressibility of downstream rockfill adversely impacting the concrete face. The document also discusses modeling earthquakes, the need for structure-specific models in some cases, and ensuring nonlinear analysis convergence. Overall, it emphasizes the importance of numerical analysis as a tool to supplement—not replace—engineering judgment, especially for extrapolating lessons from incidents at high CFRDs.
The document discusses a study that used ground penetrating radar (GPR) to develop models for estimating moisture and chloride content in concrete slabs. Concrete slab samples of varying moisture and chloride content were tested using GPR. The GPR wave attenuation correlated strongly with both the moisture and chloride levels. Two multiple regression models were developed that demonstrate a good correlation between GPR amplitude attenuation and the moisture and chloride concentrations in the concrete cover. The models can be used to estimate moisture and free chloride content in concrete, which provides useful information for assessing corrosion levels in reinforced concrete structures.
This document provides a summary of the scope of work for engineering design and installation of a new 10-inch, 22 km offshore pipeline from Palang to an FSO unit. The scope includes pipeline design, material selection, coating and cathodic protection design, engineering drawings, installation analysis using specialized software, and environmental and geotechnical data collection. Key deliverables are the wall thickness verification, free span analysis, anode design, and pipeline expansion calculation.
Rcc box culvert methodology and designs including computer methodcoolidiot07
This document discusses the methodology and design of reinforced concrete box culverts. It addresses key considerations for the structural design of box culverts, including:
1) Load cases to consider (empty, full, surcharge loads), factors like live load, effective width, earth pressure, and impact.
2) Methods for determining the coefficient of earth pressure and its effect on design. Values of 0.333 and 0.5 are compared.
3) Determining the effective width to use for live load distribution, which significantly impacts design of culverts without cushion. Different approaches in codes and literature are discussed.
4) The document aims to comprehensively cover design provisions, considerations, and justification of factors impact
This document discusses rock tunnel engineering. It introduces different types of tunnels and their purposes. Tunnels can have various cross-sectional shapes and be located underground in different ground types. Tunnels are constructed using methods like cut-and-cover, drilling and blasting, or mechanized boring machines. Geotechnical investigations for tunnels are challenging due to uncertainties in ground conditions. Rock mass classification systems help characterize rock strength. The principles of tunnel stabilization and design aim to control ground movements rather than carry ground loads by mobilizing the strength of the surrounding ground.
The document provides an overview of the "Cut-and-Cover" and "Cover-and-Cut" tunnel construction techniques. The "Cut-and-Cover" method involves excavating a trench and constructing the tunnel structure within it, then refilling the trench. The "Cover-and-Cut" method first constructs a retaining concrete shell, then excavates underneath it for tunnel construction. Both methods are used for highway and railway tunnels where shallow depths or unstable ground conditions require extra support during construction. The document discusses the design process and construction steps for each method.
Tunnelling is a serious engineering project.
In addition to large investment cost, the challenges related to long and deep tunnels are considerable.
Important aspects which needs to be considered are related to the construction works, geology, environment and operation. his module highlights all these aspects.
The document discusses foundation treatment for dams. It covers treating rock foundations by excavating to solid rock, cleaning rock surfaces, treating defects like seams, and using grouting. It also discusses treating earth foundations to provide bearing strength, prevent sliding and seepage, and protect against piping. Common earth foundation treatments include cutoff walls, impervious blankets, drainage systems, and using piles. The effectiveness of partial versus complete cutoff walls is analyzed.
This document provides an overview of tunneling, including the purposes of tunnels, effects of tunneling on the ground, tunnel lining, economic aspects, geological considerations, overbreak, and examples of important tunnels. Tunnels are used for transportation, utilities, and protection from hazards. They affect the surrounding ground and require lining for structural integrity and waterproofing. Cost, time, and construction method are economic factors to consider. Geological conditions like rock type influence tunnel design and construction challenges like overbreak. The Pir Panjal Railway Tunnel in India is highlighted as a significant tunnel project.
Dams are classified based on their purpose, materials used, and hydraulic design. The main types are embankment dams made of earth or rock, and concrete dams including gravity, buttress, and arch dams. Embankment dams use local natural materials and have lower foundation requirements but greater risks of overtopping. Concrete dams can better withstand overtopping but require stronger foundations and transportation of materials. Both dam types have advantages and disadvantages depending on the site conditions and purposes.
Major issues to be considered for the successful application of unreinforced and steel fiber reinforced concrete (SFRC) tunnel final linings concepts include:
1) Application limits related to the geotechnical environment, seismic regime, and topography that must be determined based on safety and serviceability requirements.
2) Existing design codes and recommendations provide frameworks for evaluating the safety and serviceability of these lining concepts.
3) Case studies demonstrate that unreinforced and SFRC tunnel linings have been successfully used in tunnels up to 8km and 4.8km respectively, in various ground conditions.
This document provides an overview of embankment dam design and construction. It discusses the types of embankment dams, causes of failure, and design procedures. The key points covered are:
1. Types of embankment dams include homogeneous dams with toe drains or blankets, and zoned dams with central cores and filters/blankets.
2. Causes of failure include hydraulic failures from overtopping, seepage failures from piping/leakage, and structural failures from sliding, liquefaction, or settlement.
3. Design considers safety against hydraulic, seepage and structural failures. This includes limiting seepage, ensuring stability of slopes, and providing adequate spillway capacity.
tunnelling scope, construction techniques and necessityShashank Gaurav
This document discusses tunnel construction methods and planning. It describes the main types of tunnels based on application and construction method. The key construction methods covered are cut-and-cover, pipe jacking, shield tunneling, New Austrian tunneling method, and immersed tube tunneling. For each method, the document outlines the construction sequence, advantages, and disadvantages. Proper planning stages including investigations and alignment selection are also emphasized.
This document summarizes the key aspects of box culvert design and analysis. Box culverts consist of horizontal and vertical slabs built monolithically, and are used for bridges with limited stream flows and high embankments up to spans of 4 meters. They are economical due to their rigidity and do not require separate foundations. Design loads include concentrated wheel loads, uniform loads from embankments and decks, sidewall weights, water pressure when full, earth pressures, and lateral loads. The culvert is analyzed for moments, shears, and thrusts using classical methods to determine force effects from these various loading conditions.
Importance of geological considerations while choosing tunnel sites and align...Buddharatna godboley
This document discusses the importance of geological considerations when selecting sites and alignments for tunnels. It notes that geological investigations are essential for choosing the best route, determining the excavation method, designing the tunnel, assessing costs and stability, and evaluating environmental hazards. The document provides details on how different rock types and geological structures like folding and faulting can impact tunnel construction and design. It emphasizes that understanding the area's geology is crucial for planning tunnels and minimizing risks.
Necessity/advantage of a tunnel, Classification of Tunnels,
Size and shape of a tunnel, Alignment of a Tunnel, Portals and Shafts,
Methods of Tunneling in Hard Rock and Soft ground, Mucking, Lighting
and Ventilation in tunnel, Dust control, Drainage of tunnels, Safety in
tunnel construction.
The document discusses the design of an ogee spillway for a concrete gravity dam. It describes how shifting the curve of the nappe spillway profile can save concrete by becoming tangential to the downstream dam face. It then provides sample calculations for designing an ogee spillway based on given parameters like discharge rate, dam dimensions, and river levels. These include calculating the design head, developing the upstream and downstream spillway profiles, and considering factors that affect spillway design.
This document summarizes the key loads and design considerations for concrete dams. It discusses the primary, secondary, and exceptional loads that act on gravity dams, including water load, self-weight, uplift, wave load, silt load, wind load, and earthquake load. It also covers the design of gravity dams against overturning, sliding, and material failure. Buttress and arch dam designs are briefly introduced. Thin cylinder theory for arch dam design is explained.
The document discusses various types of loads and pressures that act on underground tunnels, including:
1) Earth/rock pressures and water pressure are the most important potential loads. Live loads from surface traffic can usually be neglected.
2) Dimensions of tunnel sections must account for overburden weight (geostatic pressure) or loosening pressure (weight of loosened rock zone).
3) Lateral pressures, bottom pressures, and rock pressures are discussed. Several theories for estimating vertical and lateral loads are presented, including those by Bierbaumer, Terzaghi, and Tsimbaryevitch.
4) Rock pressures depend on factors like the quality of rock, stresses/strains around the
- The document provides information about tunnels and tunneling, including background on some of the earliest tunnels constructed by ancient Egyptians and Babylonians.
- Tunnels can be classified based on their purpose, geological location/condition, and cross-sectional shape. Examples of different tunnel types and shapes are given.
- Key geological conditions that influence tunnel planning and construction are discussed, including rock properties, groundwater conditions, and fault zones. The importance of site investigations is emphasized.
- Methods of tunnel construction in soft ground, dealing with water and gases in tunnels, and controlling temperature are outlined. Excavation methods like cut-and-cover, sequential excavation (drill-and-blast), and tunnel boring
Lyapichev. Problems in numerical analysis of CFRDs (ICOLD Bull.155)6 p.)Yury Lyapichev
The document discusses several challenges and developments in numerically analyzing concrete faced rockfill dams (CFRDs). It notes that until recently, CFRDs were designed based on experience rather than analysis. Accurate models have since shown issues like excessive compressibility of downstream rockfill adversely impacting the concrete face. The document also discusses modeling earthquakes, the need for structure-specific models in some cases, and ensuring nonlinear analysis convergence. Overall, it emphasizes the importance of numerical analysis as a tool to supplement—not replace—engineering judgment, especially for extrapolating lessons from incidents at high CFRDs.
The document discusses a study that used ground penetrating radar (GPR) to develop models for estimating moisture and chloride content in concrete slabs. Concrete slab samples of varying moisture and chloride content were tested using GPR. The GPR wave attenuation correlated strongly with both the moisture and chloride levels. Two multiple regression models were developed that demonstrate a good correlation between GPR amplitude attenuation and the moisture and chloride concentrations in the concrete cover. The models can be used to estimate moisture and free chloride content in concrete, which provides useful information for assessing corrosion levels in reinforced concrete structures.
This document summarizes key issues in the design and construction of embankment dams. It discusses common causes of embankment dam failures such as sliding due to high pore water pressure, seepage failures from hydraulic fracturing, and differential settlement causing cracks. It also outlines investigation, design, and construction processes for embankment dams and analyzes total and effective stress for stability evaluations.
This document summarizes key issues in the design and construction of embankment dams. It discusses common failure modes such as sliding due to high pore water pressure, seepage failures from hydraulic fracturing, and differential settlement causing cracks. It also examines the shear strength properties and testing of fill materials important for stability analyses. Earthquake damage patterns include liquefaction of foundations and various failure types in dam bodies depending on their configuration.
PERFORMANCE OF BEAM COLUMN JOINT WITH GEOPOLYMER MATERIAL BY NON LINEAR ANALYSISIRJET Journal
This document discusses analyzing the performance of beam-column joints using geopolymer concrete through nonlinear finite element analysis. It begins with background on the types of beam-column joints and importance of ductility. The research aims to model and analyze critical interior beam-column joints of an RCC building using ANSYS to evaluate stresses, cracks and deflections. It also reviews previous studies on geopolymer concrete and modeling beam-column joints, and outlines the methodology which includes modeling the building in STAAD Pro, identifying critical joints, and analyzing them under earthquake loads in ANSYS.
Analysis of Bund to avoid breach in Irrigation system of Sindh, Pakistan.Farhan Hussain
Deformation problem and Instability may occur in roads of katcha regions in Sindh during floods. Here an example (in 2010) in north region of Sindh, Pakistan by failure of Thori Bund which not only fail the system of Irrigation but massive destruction comes in result due to failure of Thori bund 1.21 Million houses were damaged and 2.33 Million people were died. Regarding to this major accident we should measure the stability of existing Bunds to avoid the Flood Problem
This document discusses stress modeling of pipelines strengthened with advanced composite materials. It begins by introducing the need to rehabilitate pipelines damaged by environmental factors and corrosion. Fiber reinforced polymer composites are presented as a potential new method for pipeline repair without excavation. Theoretical stress models are developed to analyze the effects of internal pressure, soil loading, and composite reinforcement on the circumferential stresses in the pipe wall. Equations are provided to calculate hoop stresses from internal pressure and bending stresses from soil loading on undamaged pipes.
Three series of push-off tests were conducted to study subbase friction characteristics for typical Korean jointed concrete pavement systems under different subbase conditions. The subbase conditions tested were: I) concrete slab directly cast on lean concrete subbase, II) polythene sheet placed between slab and subbase, and III) asphalt bond breaker layer between slab and subbase. Tests were performed at various loading rates and slab thicknesses to evaluate how these factors influence subbase friction properties. Results showed that subbase type and stiffness affected the failure plane location and shape of the friction-displacement curve. Softer subbases led to failure at the slab-subbase interface and a decreasing friction curve, while stiffer subbases
The document discusses the durability of concrete, which is defined as its ability to resist weathering, chemical attack, and other deterioration processes over its lifespan. It notes that the interaction between concrete and its environment occurs through the hardened cement paste, allowing materials from the environment to permeate into the concrete. To improve durability, the document states that environments must be better classified so that appropriate cements, water-cement ratios, reinforcement covers, and crack widths can be selected. Lower water-cement ratios produce denser, less permeable concrete and therefore improve durability by reducing cracks and disintegration over time.
Auber_Steel fiber reinforcement concrete_Slab on ground-Design NoteHoa Nguyen
This document provides design guidelines for slabs on ground using Auber steel fiber concrete. It discusses general principles of yield line design theory and describes procedures for determining the load carrying capacity of slabs. Material properties for Auber steel fibers are specified based on testing standards. The design process involves discretizing the slab cross-section into layers and determining fiber distribution. Load cases include uniform and point loads. Models are presented for analyzing the effects of temperature, shrinkage, and different load configurations. Critical aspects like shear capacity and punching are also addressed.
This document summarizes a study on modeling negative friction forces on pile foundations in loess soils prone to consolidation. It discusses European and Ukrainian design standards, previous research, and a case study modeling test pile behavior using PLAXIS 3D Foundation software. The study aims to clarify methods for incorporating negative skin friction forces resulting from soil consolidation, which can reduce pile capacity. Numerical modeling is seen as a way to better understand pile-soil interaction and deformation over time compared to physical testing alone.
Post Earthquack Slope Stability Analysis of Rubble Mound BreakwaterIJERA Editor
Rubble mound breakwaters are structures built mainly of quarried rock. Generally armourstone or artificial concrete armour units are used for the outer armour layer,which should protect the structure againist wave attack. Armour stones and concrete armoure unites in this outer layer are usually placed with care to obtain effective interlocking and consequently better stability
IRJET - Shrinkage Crack Study due to Lead Contamination in Bentonite ClayIRJET Journal
1. The document studies the effect of lead contamination on the shrinkage cracking of bentonite clay. Bentonite clay samples contaminated with varying percentages of lead (0-0.1%) were tested.
2. The results showed that with increasing lead concentration, the consistency limits (liquid limit and plastic limit) of the bentonite clay decreased. The shrinkage limit was not significantly affected. Hydraulic conductivity increased with increasing lead concentration.
3. Digital image processing was used to analyze the crack patterns of the contaminated bentonite clay samples. The crack intensity factor, which is the ratio of crack surface area to total surface area, increased with higher lead contamination levels.
Synopsis on Tribological behaviour of Nitronic-SteelDeepuDavid1
This document summarizes a synopsis report on the tribological behavior of nitronic steel. It discusses using nitronic steel for underwater parts in hydroelectric projects as 13Cr-4Ni martensitic stainless steel currently used has limited wear life. The objectives are to study cavitation erosion, solid particle erosion, and sliding erosion in hydro turbine blades made of nitronic steel and compare its erosion behavior to 13/4 martensitic stainless steel and 316L stainless steel. The work plan includes literature review and experiments to study structure-property correlation and involve metallography, tensile tests, hardness measurements, X-ray diffraction, and cavitation testing.
This document provides an overview of fracture characterisation from borehole image logs. It discusses how fractures of different sizes, apertures, and mineral infills can be imaged using various borehole tools. Direct measurements that can be taken from images include fracture location, orientation, morphology, continuity and apparent aperture. Fracture descriptions should be ground-truthed with core data. The impact of fractures on reservoir performance can be both positive and negative. Analysis of fracture image data involves displaying and separating fractures into sets, analyzing factors like density and spacing, and developing a conceptual fracture model.
This document discusses pile walls as a type of side support system for excavations. It provides information on different pile wall systems including contiguous pile walls, secant pile walls, and tangent pile walls. Continuous flight auger piling and rotary piling installation methods are described. The document also covers site investigation, soil parameters, structural design, load considerations, failure modes, and construction stages for pile walls.
special concrete and high performance concreteErankajKumar
GROUTING OF CONCRETE, advantage ofGrouting,Characteristics of Grouting, GUNTING OF
CONCRETE, Application of Guniting, Properties of Guniting, advantage and disadvantage of Guniting, UNDERWATER CONCRETING, Properties of underwater concrete, METHODS OF UNDERWATER CONCRETE, advantage and disadvantage of underwater concrete, HOT WEATHERING CONCRETE, precautions, COLD WEATHER CONCRETING, PUMPABLE CONCRETE, Requirements of Mix Design for Pumpable Concrete, Ready Mixed Concrete RMC, Types of Ready Mixed Concrete, advantage and disadvantage of ready mixed concrete, introduction in High performance concrete HPC, selection of materials, behaviour of fresh high performance concrete HPC , behaviour of Hardened High performance concrete HPC when to use High performance concrete HPC , application of HPC , Advantage of HPC , Limitations of HPC
IRJET- Study on Causes of Cracks and its Remedial Measures in Reinforced Conc...IRJET Journal
The document discusses cracks in reinforced concrete bridge piers and abutments. It first provides background on the causes of cracking, including applied loads, restraint from volume changes, and drying shrinkage. It then presents a case study of a bridge exhibiting cracks in the abutments and approaches. The cracks are thought to be caused by movement of the abutments due to issues with surrounding soils. The document outlines various remedial measures that could address abutment movement and cracking, such as soil grouting, concrete jacketing, and epoxy injection. It concludes that abutment movement must be addressed to prevent further deterioration of the bridge structure.
Rocks mechanics and its application in mining geology.
It aims at enhancing the mining process and higher yielding by reducing the chance of failures by providing information about the rocks of the mining area.
Similar to Lyapichev. Analysis, design & behavior of CFRDs (20)
This presentation summarizes the environmental problems associated with large hydropower plants and dams based on assessments by ICOLD over the last 20 years. Examples are given of issues with projects like the High Aswan Dam in Egypt and Rogun Dam in Tajikistan. While local environmental impacts must be considered in new dams and renovations, dams also address global problems through renewable energy generation and providing stable electrical grids. Dams integrate intermittent renewable sources like solar and wind power, and pumped storage helps better store large amounts of energy from these sources.
Lyapichev: Analysis, design & behavior of CFRDsYury Lyapichev
Comprehensive numerical analysis, design & behavior of some high concrete face rockfill dams (CFRDs) are given including recommendations for improvement their safety in seismic regions .
Soluciones nuevas en presas en paises con alta sismisidadYury Lyapichev
Este documento discute nuevas soluciones estructurales y tecnológicas para presas de concreto compactado con rodillo en países con alta sismicidad. Se proponen dos tipos de presas: 1) Presas simétricas de concreto muy pobre compactado con pantallas de concreto y 2) Presas simétricas con zonas exteriores de concreto plástico y zona interior de enrocado enriquecido con mortero de cemento. Estas presas ofrecen ventajas como mayor resistencia sísmica, menores costos y
“PRESAS GRANDES EN REGIONES SÍSMICAS”
ASPECTOS DE DISEÑO, CONSTRUCCION Y OPERACION
Prof., Dr. (Cienc. Tecn.), miembro del ICOLD:
YURY LYAPICHEV (RUSIA)
Boletin inicial del curso internacional (Lyapichev)Yury Lyapichev
“PRESAS GRANDES EN REGIONES SÍSMICAS”
ASPECTOS DE DISEÑO, CONSTRUCCION Y OPERACION
Prof., Dr. (Cienc. Tecn.), miembro del ICOLD:
YURY LYAPICHEV (RUSIA)
Ляпичев. Проектирование, строительство и поведение современных высоких плотин...Yury Lyapichev
Научно-практическая монография по проектированию, строительству и мониторингу поведения современных высоких плотин трех типов: из укатанного бетона, каменно-насыпных плотин с железобетонными экранами и с асфальтобетонными диафрагмами
Ляпичев. Проектирование, строительство и поведение современных высоких плотин...Yury Lyapichev
Рассмотрены 3 типа современных высоких плотин: из укатанного бетона, каменно-насыпные с железобетонным и асфальтобетонными экранами по состоянию на 2013 год
La política trata sobre la seguridad de presas nuevas y existentes. Sus objetivos son asegurar que presas nuevas sean diseñadas y construidas de manera segura por profesionales competentes, y que se evalúe la seguridad de presas existentes que podrían afectar proyectos financiados por el Banco. La política se aplica a grandes presas o presas de alto riesgo, y requiere medidas como la revisión de un panel independiente de expertos.
Lyapichev. Curso seguridad sismica de presas según de ICOLDYury Lyapichev
Este documento presenta información sobre la seguridad sísmica de presas. En 3 oraciones o menos:
El documento discute los avances en el análisis y diseño sísmico de presas desde la década de 1970, incluidos los criterios actualizados y el uso del análisis dinámico no lineal. También describe los principales problemas relacionados con la evaluación de la seguridad sísmica de presas existentes y la modelización precisa del comportamiento de las presas durante los terremotos. El documento enfatiza la importancia de considerar todos
Lyapichev. Seguridad sismica de presas (ICOLD Congreso, 2003)Yury Lyapichev
Este documento trata sobre la seguridad sísmica de presas. Discute los avances en el análisis sísmico de presas desde la década de 1970, incluido el desarrollo del análisis dinámico no lineal. También describe los criterios actuales para la evaluación de la seguridad sísmica de presas existentes y nuevas, como la selección de parámetros para terremotos de proyecto y la importancia de monitorear el comportamiento sísmico real de las presas. Además, enfatiza la necesidad de un en
Lyapichev. Direcciones para gestión de seguridad de grandes presas y obras hi...Yury Lyapichev
Este documento presenta directrices para la gestión de seguridad de presas y obras hidráulicas. Describe los fundamentos de la seguridad de presas, incluyendo objetivos, principios y gestión del riesgo. Explica los componentes de un sistema de gestión de seguridad de presas, como políticas, planificación, implementación, verificación, informes y evaluación. También cubre temas como clasificación de presas, operación, mantenimiento, vigilancia, ensayos, revisiones de seguridad, análisis estructural, auditor
Ляпичев. Оценка банковского отчета ТЭО фирмы Коин и Белье по Богучанской ГЭСYury Lyapichev
Оценка банковского Отчета ТЭО фирмы Коин и Белье (Франция) по Богучанской ГЭС и каменнонабросной плотине с асфальтобетонной диафрагмой показала, что институт Гидропроект представил фирме ошибочные (расчетные) параметры грунтов плотины и основания вместо принятых во Франции их предельных величин, что во многом обесценило рекомендации фирмы, особенно по бетонной станционной плотине
Electric vehicle and photovoltaic advanced roles in enhancing the financial p...IJECEIAES
Climate change's impact on the planet forced the United Nations and governments to promote green energies and electric transportation. The deployments of photovoltaic (PV) and electric vehicle (EV) systems gained stronger momentum due to their numerous advantages over fossil fuel types. The advantages go beyond sustainability to reach financial support and stability. The work in this paper introduces the hybrid system between PV and EV to support industrial and commercial plants. This paper covers the theoretical framework of the proposed hybrid system including the required equation to complete the cost analysis when PV and EV are present. In addition, the proposed design diagram which sets the priorities and requirements of the system is presented. The proposed approach allows setup to advance their power stability, especially during power outages. The presented information supports researchers and plant owners to complete the necessary analysis while promoting the deployment of clean energy. The result of a case study that represents a dairy milk farmer supports the theoretical works and highlights its advanced benefits to existing plants. The short return on investment of the proposed approach supports the paper's novelty approach for the sustainable electrical system. In addition, the proposed system allows for an isolated power setup without the need for a transmission line which enhances the safety of the electrical network
Presentation of IEEE Slovenia CIS (Computational Intelligence Society) Chapte...University of Maribor
Slides from talk presenting:
Aleš Zamuda: Presentation of IEEE Slovenia CIS (Computational Intelligence Society) Chapter and Networking.
Presentation at IcETRAN 2024 session:
"Inter-Society Networking Panel GRSS/MTT-S/CIS
Panel Session: Promoting Connection and Cooperation"
IEEE Slovenia GRSS
IEEE Serbia and Montenegro MTT-S
IEEE Slovenia CIS
11TH INTERNATIONAL CONFERENCE ON ELECTRICAL, ELECTRONIC AND COMPUTING ENGINEERING
3-6 June 2024, Niš, Serbia
Low power architecture of logic gates using adiabatic techniquesnooriasukmaningtyas
The growing significance of portable systems to limit power consumption in ultra-large-scale-integration chips of very high density, has recently led to rapid and inventive progresses in low-power design. The most effective technique is adiabatic logic circuit design in energy-efficient hardware. This paper presents two adiabatic approaches for the design of low power circuits, modified positive feedback adiabatic logic (modified PFAL) and the other is direct current diode based positive feedback adiabatic logic (DC-DB PFAL). Logic gates are the preliminary components in any digital circuit design. By improving the performance of basic gates, one can improvise the whole system performance. In this paper proposed circuit design of the low power architecture of OR/NOR, AND/NAND, and XOR/XNOR gates are presented using the said approaches and their results are analyzed for powerdissipation, delay, power-delay-product and rise time and compared with the other adiabatic techniques along with the conventional complementary metal oxide semiconductor (CMOS) designs reported in the literature. It has been found that the designs with DC-DB PFAL technique outperform with the percentage improvement of 65% for NOR gate and 7% for NAND gate and 34% for XNOR gate over the modified PFAL techniques at 10 MHz respectively.
Understanding Inductive Bias in Machine LearningSUTEJAS
This presentation explores the concept of inductive bias in machine learning. It explains how algorithms come with built-in assumptions and preferences that guide the learning process. You'll learn about the different types of inductive bias and how they can impact the performance and generalizability of machine learning models.
The presentation also covers the positive and negative aspects of inductive bias, along with strategies for mitigating potential drawbacks. We'll explore examples of how bias manifests in algorithms like neural networks and decision trees.
By understanding inductive bias, you can gain valuable insights into how machine learning models work and make informed decisions when building and deploying them.
A SYSTEMATIC RISK ASSESSMENT APPROACH FOR SECURING THE SMART IRRIGATION SYSTEMSIJNSA Journal
The smart irrigation system represents an innovative approach to optimize water usage in agricultural and landscaping practices. The integration of cutting-edge technologies, including sensors, actuators, and data analysis, empowers this system to provide accurate monitoring and control of irrigation processes by leveraging real-time environmental conditions. The main objective of a smart irrigation system is to optimize water efficiency, minimize expenses, and foster the adoption of sustainable water management methods. This paper conducts a systematic risk assessment by exploring the key components/assets and their functionalities in the smart irrigation system. The crucial role of sensors in gathering data on soil moisture, weather patterns, and plant well-being is emphasized in this system. These sensors enable intelligent decision-making in irrigation scheduling and water distribution, leading to enhanced water efficiency and sustainable water management practices. Actuators enable automated control of irrigation devices, ensuring precise and targeted water delivery to plants. Additionally, the paper addresses the potential threat and vulnerabilities associated with smart irrigation systems. It discusses limitations of the system, such as power constraints and computational capabilities, and calculates the potential security risks. The paper suggests possible risk treatment methods for effective secure system operation. In conclusion, the paper emphasizes the significant benefits of implementing smart irrigation systems, including improved water conservation, increased crop yield, and reduced environmental impact. Additionally, based on the security analysis conducted, the paper recommends the implementation of countermeasures and security approaches to address vulnerabilities and ensure the integrity and reliability of the system. By incorporating these measures, smart irrigation technology can revolutionize water management practices in agriculture, promoting sustainability, resource efficiency, and safeguarding against potential security threats.
A review on techniques and modelling methodologies used for checking electrom...nooriasukmaningtyas
The proper function of the integrated circuit (IC) in an inhibiting electromagnetic environment has always been a serious concern throughout the decades of revolution in the world of electronics, from disjunct devices to today’s integrated circuit technology, where billions of transistors are combined on a single chip. The automotive industry and smart vehicles in particular, are confronting design issues such as being prone to electromagnetic interference (EMI). Electronic control devices calculate incorrect outputs because of EMI and sensors give misleading values which can prove fatal in case of automotives. In this paper, the authors have non exhaustively tried to review research work concerned with the investigation of EMI in ICs and prediction of this EMI using various modelling methodologies and measurement setups.
Generative AI leverages algorithms to create various forms of content
Lyapichev. Analysis, design & behavior of CFRDs
1. Analysis, design and behavior of concrete face rockfill dams (CFRDs)
1.1. Numerical analyses of CFRDs
CFRDs are different from rockfill dams with clay or asphalt concrete cores because: 1) concrete
face is impervious and acted upon by the hydrostatic pressure, causing high compressive stresses
on the soils in the lower part of the transition zones. Therefore, the upstream slope stability
generally is ignored not only in static and seismic analyses with full reservoir, but also deep
drawdown of reservoir that it is inadmissible. As the upper part of this slope (usually with
H/V=1.4-1.5) with the under-laying transition zone is not subjected to hydrostatic pressure it is
much more sensitive to maximum seismic acceleration in the upper dam part that the less steep
(H/V=1.6-1.7) downstream slope of rockfill with much more shear strength.
Until recently it was considered useless to perform numerical analyses of CFRDs and
promoters of these dams claimed that their design was result of only experience and empirics.
A number of incidents affected several recent high CFRDs, which has enlighted the interest of
numerical models to keep control on extrapolation towards higher dams. It has been shown that
not only stresses increase proportionally to the dam height, but even the dam stability. The valley
shape has been identified as an important factor, which induces bank-to-bank movements of
rockfill and very high compressive stresses in concrete face. Such problems are indeed quite
complex for numerical analyses, because:
• The problem is in general tridimensional (3D),
• The response of rockfill to loads requires non-linear constitutive laws with rather large
displacements, including sliding movements along the rock abutments.
• The huge contrast between the large, deformable rockfill and the slender, rigid concrete
face creates numerical problems, all the more as sliding may occur along the contact surface
between both materials.
Fig. 1.1 gives an example of model mesh for CFRD,
where rockfill and concrete face are presented with
volume finite elements. In case of rock foundation it
can be omitted from the model due to its very low
compressibility, compared to the rest of the model.
Fig. 1.1. Finite element 3-D model of CFRD: 1- Left
dam end; 2 – Crest; 3 – Right crest end; 4 – Upstream
concrete face; 5 – Rock foundation shape.
In this context, Problem 10B “Analysis of CFRD including concrete face loading and
deformation” was proposed for the 10th
bench workshop, based on information of the 145 m high
Mohale CFRD in Lesotho. Four solutions were presented, with results under the form of
displacements and stresses in the fill during construction, stresses and joint openings in the
concrete face. Stresses consistent with the damages observed in the prototype were given by 2
solutions. The main reason for these damages was identified as a high compressibility of rockfill
under high stresses, due to the breakage of rock particles.
Recently many 140-200 m high CFRDs (Mohale dam in Lesotho, Barra Grande and Campos
Novos in Brazil, etc.) have serious problems with intense cracking of concrete face and large
opening of perimeter joints that’s results in dangerous seepage and subsequent high-cost repair.
It should be emphasized that three recent incidents, including the Mohale dam, show the need to
carefully evaluate and analyze every aspect of a project when extrapolating from precedent. This
should be based on good engineering judgment and complemented with detailed analysis tools.
1.2. Behavior of concrete face of CFRDs during first impounding of the reservoir
The hydrostatic water pressure is pressing the concrete face and underlying transition zones.
Thus, the shear resistance against sliding of the concrete face on these zones is also growing with
increasing water pressure. At the same time the water pressure prevents the separation of the
concrete face from the soil of underlying transition zone. Cracking and damage of concrete face
is more likely to be expected in its upper part. At greater water depth local joint damage in the
2. concrete face due to compression and shear but also opening of vertical joints must be expected,
leading to increased leakage.
Untill recently the trend in CFRD design, based on the intuition of specialists, was to pay
great care on the placing of rockfill materials just below the concrete slabs with which these
dams are provided, and to accept much less care in the downstream area (thicker layers, lower
quality of rock, etc.). Some of these dams have shown many damages on slabs and high leakage,
due to excessive and uneven deformability of rockfill zones.
Accurate models with non-linear properties of rockfill have shown the adverse effect of
excessive compressibility of the downstream shell on the deformations imposed to the concrete
face (Anthiniac & al., 2002). The influence of excessive downstream slopes has also been put
into evidence. It is still difficult to obtain realistic rockfill properties from laboratory tests, due to
the size of finite elements and samples. Research is underway to understand the plastification
phenomenon at the scale of the block, whose objective is to provide an extrapolation law to
derive the behavior of large size rockfill from more manageable samples with only small blocks.
One of the difficulties brought by non-linear process in FE analyses is the need to check the
process convergence. Non-linear software generally use only a global convergence criterion,
based on the proportion of unbalanced energy relative to the total deformation energy. This
criterion as proved to fail in some specific cases, e.g. opening of joints in a concrete slab of a
CFRD. The reason is that even a small unbalanced local force may prevent a whole structure
from collapsing (this is the “zipper” effect). Only the engineer can detect such critical cases, and
it is therefore necessary that all software with non- linear capabilities propose means to detect
(and visualize) the amount of local unbalanced forces, at different steps of the analysis.
1.3. General seismic resistance of CFRD
The following failure modes due to seismic actions are considered for CFRDs:
(1) sliding of shallow materials along planar surfaces;
(2) wedge failure or deep-seated rotational failure (Seed et al., 1985);
(3) vulnerability of perimetric joints (Wieland, 2008) as the joint (protected with filters) is a
critical element and washing out of foundation soil is to be prevented in leakage case;
(4) cracking of concrete face due to high compressibility of the upstream transition zones. Use
in these zones well graded and compacted fine and coarse-grained soil of low compressibility
and their compaction can minimize cracking of concrete face;
5) long-term settlements of well compacted rockfill is in the range of 0.1-0.2 % of the dam
height. Strong ground shaking can produce its settlements in the range of about 0.5-1.0 m.
For assessment of the seismic performance of concrete face, the analysis of the effect of the
cross-canyon earthquake component is to be made to receive realistic values of dynamic stresses
in the concrete face and its response to these forces. The behavior of the rigid concrete face for
in-plane motions is very different from that of the rockfill in CFRD, thus the rockfill motion in
crest direction will be restrained by the concrete face. Therefore, for cross-canyon vibration, the
rigid concrete face attracts seismic forces from the dam. Hence, very high stresses may develop
in the face. Shear failure and/or spalling of concrete may occur in the highly stressed joints.
The recent case of CFRD serious damage and concrete face intense cracking was registered in
156 m high Zipingpu CFRD (China), which was designed for peak ground acceleration of 0,26g.
The dam was subjected to very strong ground shaking of Wenchuan earthquake (magnitude 8.0)
in May 12, 2008. The seismic intensity at the dam site in the range of 9-10 (Chinese seismic
scale) was beyond the value accepted in the design. During the earthquake the reservoir level
was low that was the main cause of the crest dam damage and concrete face cracking. On the
crest the recorded peak accelerations were over 2g; however, as the concrete crest behaved
differently from the dam body and since the concrete part also separated from the rockfill the
dynamic behavior of the concrete dam crest was quite different from that of the rockfill.
After the earthquake the maximum settlement at the dam crest was 735 mm and the horizontal
downstream deflection was 180 mm. The cross-canyon deformation of both abutments was 102
3. mm. Due to the reservoir low level at earthquake, it is difficult to estimate what the dam
behavior, the concrete face and waterproofing system would have been if the reservoir were full.
1.4. General recommendations for dynamic analysis of CFRDs
3D dynamic response of the system “dam-foundation-reservoir” affects the values of joint
opening of concrete face, the condition of the dam contact with abutments, behavior of control
gallery and overall picture of displacement and stress fields.
1. The boundaries of computational domain of dam foundation are appointed from the
condition of their sufficient remoteness so, that their effects on dam behavior would not be
significant. Justification the length of dam foundation in dynamic problem is complicated by the
need to eliminate the possibility of wave reflection from boundaries of computational domain.
Modern programs, such as FLAC, ADINA and Abaques allow on boundaries of the selected
computational domain to apply conditions of passing or absorption of seismic waves.
2. Degree of reliability of the results of dynamic analyses significantly depends on the
likelihood of estimated conditions on contact elements of the system. On contacts of the face
slab with transition zone should be placed one-sided links (contact works only in compression)
taking into account friction between concrete face and transition zones. FLAC, ADINA and
Abaques programs allow to realize these conditions.
3. An important issue is the choice of material models of the system “dam-foundation”.
Modern computers and software allow realizing in analyses different models of dam materials:
for concrete – elastic models, for soils – nonlinear elastic, elasto-plastic, plastic, etc. However,
there are great difficulties in selection of reliable dynamic parameters of materials of the system.
4. In dynamic (seismic) analysis the stress-strain state of the system from the static loads
(hydrostatic pressure of reservoir and dead weight of dam and face) should be considered as an
initial stress field (with zero displacements).
5. It is recommended to apply the seismic load (real and synthetic accelerograms) on the
lower boundary of the computational domain of foundation. It is permissible to apply the seismic
load directly to the bottom of the dam, if in the estimated accelerograms the dam influence on
them is already considered.
6. Modern computers and software allow taking into account in the dynamic analyses the loss
of energy due to internal friction by entering into the equations of motions the corresponding
damping coefficients.
7. With a full formulation of the problem (taking into account contact and material
nonlinearity of the system, with incorporating into computational domain the foundation) it is
required the solution by direct stepwise integration.
8. In the static analysis it is required the sizes of finite elements to be selected roughly so, that
in the zones of proposed changes of stress signs were at least five elements.
9. In the dynamic problems the sizes of elements must be no more than 1/5 of the length of
the shortest seismic wave. Researcher should choose, if program allows, a computational method
(explicit or implicit): from which the required step solution for its stability or accuracy depends
on. However, this solution step must be agreed with the step of the digitizing of accelerograms.
As a result of the studies carried out by varying design parameters of materials of the system a
researcher can get all necessary information the development to justify the dam and face slab. If
there is full information the development the dam structure is not a problem.
1.5. General design recommendations for seismic safety of high CFRDs
For the design of high CFRDs in highly seismic regions the following principal measures are
recommended, which can improve their seismic safety and behavior:
(1) downstream slope flattening in the upper part of CFRD (≈0.2H) to reduce its seismic shear
deformations;
(2) sufficient freeboard (accounting crest settlements and gravitational waves in the reservoir);
(3) wide crest (improves safety of the crest part of dam and increases resistance against
overtopping from gravitational waves);
(4) use of geogrid and other techniques to strengthen both slopes of crest part of CFRD;
4. (5) proper selection of dam materials and their zoning in dam body: well-compacted gravels
or crushed stones in the upstream transition zones and pebbles in the central dam part to decrease
their compressibility and deflection of concrete face during the reservoir impounding, solid
rockfill in the downstream slope with its maximum angles of inner friction under seismic loads;
(6) in gravel-fill CFRDs the upstream drainage zone with its horizontal part of coarse gravel
protected with filters should be provided to allow free draining of water leaking through the
cracked concrete face and further evacuating of water through gravel-fill without its piping;
(7) new effective method of decrease (up to 50-55%) of concrete face deflection by using
poor RCC zone instead of the upstream transition zone or by sluicing this zone with cement
mortar. This method was proposed in design of 275 m high Kambarata-1 CFRD in Kyrgyzstan
and 190 m high Sogamoso CFRD in Colombia;
(8) provision of bottom outlet to lower the reservoir if the concrete face or water-proofing
system is damaged;
(9) concrete face slabs with smaller width to decrease their non-uniform deformations near
steep abutments;
(10) arrangement of reinforcement of the concrete face to improve its load bearing capacity
in-plane and out-of-plane and its ductility;
(11) arrangement of proper joint system including horizontal joints and selection of the joint
width to account for the reversible nature of seismic response;
(12) water-proofing system of face slabs and plinth joint to account for static and seismic
movements of the joint.
References:
Kreuser H. (2000). “The use of risk analysis to support dam safety decision and management”, General
Report to Q.76, 20th
ICOLD Congress, Beijing, China.
Chen S.H., Wang J.S., Zhang J.L.,(1996).”Adaptive elasto-plastic FEM analysis for hydraulic
structures”. Journ. of Hydraulic Eng., 19 (2), 68-75.
Ghrib F., Leger P., Tinawi R., Lupien R. (1997). “Seismic safety evaluation of gravity dams”
Hydropower and Dams, Issue 2, pp. 126-138.
Fanelli M., Salvaneschi P. (1993). “A neural network approach to the definition of near-optimal arch
dam shape”. Dam Engineering, Vol. IV, Issue 2.
Carrere A., Colson M., Goguel B. (2002). “Modeling: a means of assisting interpretation of reading”.
Proc. 20th
ICOLD Congress (Beijing), Q.78, R.63, Vol. 3.
Anthinianc P., Carrere A., Develay D. (2002). “The contribution of numerical analysis to the design of
CFRD”, Hydropower and Dams, Vol.9, Issue 4.
2. New structures of high concrete face rockfill dams (CFRDs)
Many high (more than 100 m) CFRDs have serious problems with intense cracking of concrete
faces and large openings of perimeter joints that results in dangerous seepage and subsequent
high cost repair (A. Marulanda, 2006). The new effective method to prevent or mitigate these
problems was proposed for 275 m high Kambarata-1 CFRD in Kyrgyzstan and 190 m high
Sogamoso CFRD in Colombia, both in very seismic regions.
2.1. Kambarata-1 CFRD (design variant, H=275 m, Kyrgyzstan) on rock foundation
• This dam was designed in the USSR as a rockfill dam built by the directional blasting of rock
banks of the dam site. At present, there is an urgent need for an independent international design
expertise of the dam due to its complex environmental and technological problems that include
the unpredictable results of the great explosion of rock banks of the dam site.
• Taking into account these problems a new design variant of 275 m high CFRD was developed
with the field-proven technology of its construction.
• Since the dam height is 40 m more than height (235 m) of Shubuya CFRD in China and dam is
located in a high seismic region of 9 grade per MSK-64 scale, the special measure was proposed
to reduce the concrete face deflections (normal to face): the 3-6 m thick upstream transition
gravel zone was replaced by roller compacted lean concrete (RCC) with low compressibility.
• 2D analysis of the stress-strain state by ADINA program with the elasto-plastic Mohr-Coulomb
model of rockfill and RCC zone with different schemes of dam construction and reservoir filling
5. showed that the concrete face maximum deflection can be reduced in two times comparing with
the upstream gravel zone that greatly increased the dam safety.
• The confined dam profile and high speed of its construction will provide a great technological,
economic and environmental advantages comparing with the old design of blasted rockfill dam.
Fig. 2.1. Longitudinal section and cross-section of Kambarata-1 CFRD (H=275 m)
Fig. 2.2. Structural details of Kambarata-1 CFRD (H=275 m)
6. A. Results of 2D static stress-strain analysis of the 275 m high Kambarata-1 CFRD
with the upstream transition gravel zone 2B under concrete face
Fig. 2.3. F.E. mesh for 3 stages of construction. Fig. 2.4. F.E. mesh for 5 stages of construction.
Results of 2D static analysis for 5 stages of dam construction (Fig. 2.5-2.8) showed that vertical
compressive stresses are distributed uniformly through the dam height, reaching 6 MPa in the
dam heel. In the upstream transition gravel zone under the concrete face there is a concentration
of the compressive stresses between 0.6 and 2.6 MPa.
Fig.2.5. Horizontal displacements, m. Fig. 2.6. Vertical displacements, m.
Fig. 2.7. Horizontal stresses, Pa. Fig. 2.8. Vertical stresses, Pa.
B. Results of 2D static stress-strain analysis of the 275 m high Kambarata-1 CFRD
with the upstream supporting zone of lean RCC under concrete face
Fig.2.9. Horizontal displacements, m. Fig. 2.10. Vertical displacements, m.
Fig. 2.11. Horizontal stresses, Pa. Fig. 2.12. Vertical stresses, Pa.
Conclusions
1. For dam construction in 5 stages the concrete face maximum deflection is equal to 120 cm,
which is 20% less than the same deflection for 3 stages.
2. Reduction of face deflection with RCC supporting zone is very effective: the face maximum
deflection is only 50 cm or 2.4 times less than face deflection with the gravel transition zone.
7. 3. CFRD variant with lean RCC zone as a support for concrete face provides a great reduction
of the cost and time of dam construction compared with the rockfill blasted-type dam. Therefore,
CFRD variant is to be considered, as a principal one in the final design.
2.2. 190 m high CFRD Sogamoso (Colombia, under construction) on rock foundation
The 2D stress-strain state analysis of Sogamoso CFRD was made by ADINA program with
elasto-plastic model of dam materials with Mohr-Column criterion. The great influence of
consequence of dam construction and reservoir filling on stress-strain state of dam was received.
The new effective method of decrease (40-55%) of deflection of concrete face by inclusion of
6-3 m thick RCC supporting zone (instead of upstream transition zone of gravel, 2B) under the
concrete face was proposed for this dam.
Fig. 2.13. Cross-section of Sogamoso CFRD (190 m) with upstream RCC coffer-dam (h=36 m)
Table 1. Design parameters of Mohr-Coulomb elasto-plastic model for dam materials
Parameters Zone 3А Zone 2B
(RCC)
RCC
coffer dam
Zone 3D Zone3B Zone 3C
Deformation modulus,
MPa
50 500 500 20 40 30
Poison’s coefficient 0,3 0,2 0,2 0,33 0.32 0.33
Dry density, t/m3
2,0 2,35 2,35 1,93 2.04 1.83
Angle of internal friction φ
(grades)
42 40 40 35 44 35
Cohesion, MPa - 0,1 0,1 - - -
Fig. 2.14. Five stages of dam construction considered in static analysis of stress-strain state
8. Fig. 2.15. Finite element mesh (846 super elements) in static dam analysis of stress-strain state
Fig. 2.16. Horizontal displacements (m) in Sogamoso CFRD with RCC support zone under concrete face
Fig. 2.17. Vertical displacements (m) in Sogamoso CFRD with RCC support zone under concrete face
Conclusions
1. For 5 stages of dam construction and reservoir filling the maximum deflection of concrete face with
underlying 2B transition gravel zone (3-6 m wide) can reach 180 cm.
2. In case of replacement of the transition zone 2B by RCC 3-6 m wide supporting zone the maximum
deflection of concrete face will be only 95 cm that greatly improve the dam safety.
9. 3. Static and dynamic analyses of the heightening (from 43 to 82 m) of
concrete face gravel dam CFGD Limon (Peru)
3.1. Introduction
In June 2012 the Government of Lambayeque province (Peru) invited me as an international
consultant and member of ICOLD Committee on Dam Design to perform the expert validation
of design of the heightening of concrete face gravel dam (CFGD) Limon from 43 to 82 m. The
dam is one of the main element of project, called “Proyecto Especial Olmos–Tinajones (PEOT)”.
The hydraulic (transfer) scheme of Olmos multi-purpose project (mainly for hydropower and
irrigation purposes) includes the TransAndes water-transfer 26 km long tunnel now completed.
The 82 m high Limon CFGD is located on the right bank of the Huancabamba river in the
remote region of Andes with a very high seismicity (North-East of Peru, 980 km from Lima).
In the first PEOT project, developed by Hydroproject Institute (Moscow) in 1982, the variant
of 82 m high Limon rockfill dam with clay core was adopted as one-stage dam construction. But
later due to the political and financial problems in Peru the project implementation was delayed
for nearly 20 years and was resumed as a two-stage construction by BOT scheme, proposed by
Odebrecht construction company (Brazil). The company changed the Soviet design of one-stage
82 m high Limon traditional rockfill dam in favor of two-stage CFGD (43 and 82 m high).
3.2. Seepage analysis Limon CFGD (H=82 m) and its alluvial (40 m deep) foundation
In the figure 3.1a is presented the geometry of dam with zones of materials and its 40 m deep
alluvial strata of foundation in channel section 10-10' and their permeability coefficients. In the
figure 3.1b is presented the finite element mesh of dam and its foundation in channel section 10.
Fig. 3.1a. Zoning and permeability of soils of CFGD Limon H=82 m and its foundation in channel section
Fig. 3.1b. Finite element mesh of CFGD Limon H=82 m and (40 m deep) foundation in channel section
10. Fig. 3.2a. Equipotential lines of the total seepage heads in rock foundation below the concrete diaphragm
The results of the equipotential lines of total seepage heads in the rock foundation below the
plastic concrete diaphragm are presented in the figure 3.2a, verifying the significant reduction of
the total seepage heads by the effect of the plastic concrete diaphragm in the dam foundation.
Also, in the figure 3.2b is verified the significant reduction of the seepage pressure heads in the
rock foundation mainly due to the plastic concrete diaphragm.
Fig.3.2b. Equipotential lines of seepage pressure heads in rock foundation below the concrete diaphragm
Table 3.1 shows the unit seepage flows in the dam foundation for construction stages of H=43
m and H=82 m in sections 8-8' (in right abutment) and 10-10' (channel section) below the
concrete diaphragm, in the central dam axis and below the dam toe. The relationship of unit
seepage flows in section 8-8' shows that seepage flow in the foundation of the dam H=82 m
would be more than twice the seepage flow in the foundation of the dam H=43 m.
Table 3.1. Unit seepage flows in the dam foundation for construction stages of H=43 m and H=82 m
Dam Section
Unit seepage flows (m3
/s/m)
Below concrete
diaphragm
In axis of dam
cross-section
Below toe of
downstream slope
I Stage
H = 43 m
8 - 8' 1.373 x 10-3
1.37 x 10-3
0.744 x 10-3
10 - 10' 1.495 x 10-3
1.38 x 10-3
0.652 x 10-3
II Stage
H = 82 m
8 - 8' 2.865 x10-3
2.759 x 10-3
1.904 x 10-5
10 - 10' 3.163 x 10-3
2.791 x 10-3
0.536 x 10-3
Relation
QH82/QH43
8 - 8' 2.09 2.01 2.56
10 - 10' 2.12 2.02 0.82
11. 3.3. Seismic (dynamic) analysis of 82 m high Limon CFGD under MCE action (Amax=0.57g)
The main results of dynamic nonlinear analysis of stress-strain state of Limon CFGD (H=82 m,
variant 2 with additional downstream rockfill zone) with full reservoir under Maximum Credible
Earthquake (MCE) action of the Mar-Chile Earthquake accelerogram are given in fig. 3.3-3.15.
Another MCE of the Lima-Peru Earthquake accelerogram was considered also in the dynamic
analysis, but its action was less dangerous than that of the Mar-Chile Earthquake accelerogram.
In fig. 3.3 the accelerogram of Mar-Chile Earthquake normalized to the maximum acceleration
of Amax=0.57g is shown. The Mar-Chile Earthquake with the return period T=5000 years and
Amax=0.57g corresponds to the recommendations of ICOLD Bulletin 148 (2010) and was much
more dangerous than adopted in previous (2009) brazilian design: Amax=0.39g, T≈1000 years.
The static and dynamic analyses of stress-strain state of Limon CFGD (H=43 and 82 m) were
made by FLAC software (USA), which was estimated in the ICOLD Congress (Canada, 2003) as
one of the best software for dynamic analyses of large rockfill dams including CFRDs. The finite
element model of Limon CFGD (H=43 and 82 m) with its foundation is shown in the fig. 3.4.
Fig. 3.3. Accelerogram of Mar-Chile Fig. 3.4. The finite element model of Limon CFGD
Earthquake normalized to Amax=0.57g (H=43 and 82 m) with its foundation
Parameters of the elasto-plastic model with Mohr-Coulomb criterion for dam materials and
foundation soils in static analyses of Limon CFGD (H=43 and 82 m) are given in the table 3.2.
Table 3.2. Parameters of Mohr-Coulomb model in static analyses of Limon CFGD (H=43 and 82 m)
Numbers and names of
zones of dam materials
and foundation soils
Material
or soils
Dry density
and void ratio
Parameters of deformation Parameters of shear
strength of materials
γdr, t/m3
n E
(MPa)
Angle of
dilatancy (0
)
ν C (MPa) ψ(0
)
1-st stage dam (H=43 m)
1, 3. Foundation Alluvium 2,15 0,2 108 0 0,30 0 42
2. Diaphragm Concrete 2,25 0 320 0 0,40 0,4 30
4. Plint slab Concrete 2,5 0 20000 0 0,17 1,0 60
5. Embankment zone Gravels and
pebbles
2,2 0,15 168 0 0,30 0 46,5
6. Transition zone Gravels 2,15 0,2 150 100
0,33 0 42
7. Transition zone Sand 2,1 0,25 100 100
0,33 0 40
8. Concrete face Concrete 2,5 0 20000 0 0,17 1,0 60
2-nd stage dam (H=82 m)
9. Embankment zone Gravels 2,2 0,15 168 0 0,30 0 46,5
10. Embankment zone Gravels 2,2 0,15 168 0 0,30 0 46,5
11. Transition zone Gravels 2,15 0,2 150 100
0,33 0 42
12. Transition zone Sand 2,1 0,25 100 100
0,33 0 40
13. Concrete face Concrete 2,5 0 20000 0 0,17 1,0 60
14. Downstream zone
with 2 berms
Pebbles 2,1 0,25 150 0 0,30 0 46,5
12. Fig.3.5. Scheme of CFGD Limon (H=42 and 82 m) Fig.3.6.Scheme of CFGD Limon (H=43 and 82 m) with
(adopted variant with d-s zone 14 with 2 berms) variable shear angles of gravel and pebble zones 10-11, 15-17
Table 3.3.Values of shear angles of gravel and pebble zones 10-11, 15-17 depending on normal stresses
Normal stresses, σn , MPa 0,2 0,5 0,8 1,0 ≥1,2
Shear angles (0
) of gravel and pebble zones 46,50
46,30
42,00
41,10
40,00
Scheme of zoning of CFGD Limon (H=82 m) with variable shear angles of gravel and pebble
zones 10-11, 15-17 (Fig.3.6) was used in the pseudo-static analyses of the downstream slope
stability under action of the acceleration in dam foundation Ahor =2/3• Amax =2/3• 0.57g=0.38g.
Fig.3.7. Distribution of seismic accelerations through Fig.3.8.Factors of seismic (Fmin=1,19>Fperm=1,06) and static
the dam height (H=82 m) using shear wedge method stability (Fmin=1,69>Fperm=1,25) of downstream slope
The distribution of seismic accelerations through the dam height was received according to
Russian seismic design norms for dams (SNiP-2003) using the shear wedge method (Figure 3.7).
Figure 3.8 shows results of static (the most dangerous circular surface 2) and seismic (the most
dangerous circular surface 1) stability of downstream slope of Limon CFGD (H=82 m) taking
into account the variable shear angles of gravel and pebble zones 10-11, 15-17. This figure show
that the minimum factor of the downstream slope stability under action of seismic loads is more
that permissible as per design norms SNiP-2003 (Fmin=1,22>Fperm=1,06) and corresponds to the
deep circular sliding surface between the dam crest and upper alluvial layers of dam foundation.
The comparison of results of the seismic stability analysis of the downstream slope of Limon
CFGD (H=82 m) with additional pebble zone 14 with two berms (fig.3.5) with results of the
same analysis of the dam but without the additional zone show that the inclusion of this zone in
the downstream slope provide a significant increase of the minimum factor of the downstream
slope stability from 1.05 up to 1.22).
Below in figures 3.9-3.12 the main results of dynamic nonlinear analysis of stress-strain state
of Limon CFGD (H==43 and H=82 m, variant with the additional downstream pebble zone) with
full reservoir under action of MCE of the Mar-Chile Earthquake accelerogram are presented.
Parameters of Mohr-Coulomb model used in the dynamic nonlinear analysis of Limon CFGD
(H=43 and 82 m) are given in table 3.4.
13. Table 3.4. Parameters of Mohr-Coulomb model in dynamic analyses of Limon CFGD (H=43 and 82 m)
Note: (σm) – medium stress (effective) in kPa
Fig. A. Curves of reduction of the shear modulus G/Gmax and
initial coefficient of damping ξ,% of soils of the dam and
its foundation
Fig. 3.9. Zones of Limon CFGD (H=43 and 82 m) with the shear and tension stress state of soils
under action of SMC of the Mar-Chile Earthquake accelerogram with Amax=0.57g
Numbers and
names of zones of
dam materials and
foundation soils
Material
or soils
Dry density
and void
ratio
Dynamic
modulus of
elasticity
Edyn
,, MPa
Shear modulus
Gmax (MPa)
Initial
coefficient of
damping ξ, %
Reduction of
parameters
Gmax and ξ
γdr,
t/m3
n
1-st stage dam (H=43 m)
1, 3. Foundation Alluvium 2,15 0,2 1300 Gmax=35(σm)0,5
5 see Fig. A
2. Diaphragm Concrete 2,25 0 1600 G= Edyn
/ [2(1+ν)] 3 --
4. Plint slab Concrete 2,5 0 20000 G= Edyn
/ [2(1+ν)] 2 --
5. Embankment
zone
Gravels and
pebbles
2,2 0,15 2000
Gmax=40(σm)0,5
5 see Fig. A
6. Transition zone Gravels 2,15 0,2 1000
Gmax=22(σm)0,5
4 see Fig. A
7. Transition zone Sand 2,15 0,2 700
Gmax=20(σm)0,5
4 see Fig. A
8. Concrete face Concrete 2, 5 0 20000
G= Edyn
/ [2(1+ν)]
5 --
2-nd stage dam (H=82 m)
9. Embankment
zone
Gravels 2,2 0,15 2000
Gmax=40(σm)0,5
5 see Fig. A
10. Embankment
zone
Gravels 2,2 0,15 2000
Gmax=40(σm)0,5
5 see Fig. A
11. Transition zone Gravels 2,15 0,2 1000 Gmax=22(σm)0,5
4 see Fig. A
12. Transition zone Sand 2,1 0,25 700
Gmax=20(σm)0,5
4 see Fig. A
13. Concrete face Concrete 2,5 0 20000 G= Edyn
/ [2(1+ν)] 5 -
14. Downstream zone
with 2 berms
Pebbles 2,15 0,2 1500 G=Edyn
/[2(1+ν)] 5 see Fig. A
14. The dam zones with the shear stress state of soils are painted in orange and zones with the
tension stress state of soils are painted in blue (Figure 3.9).
Under action of the Mar-Chile Earthquake the dam would suffer elasto-plastic deformations
with large plastic displacements in the wide zone of the downstream slope (Figure 3.10).
The large plastic (residual) deformations modified the dynamic stress-strain state of the dam
and its foundation (Figures 3.10-3.11).
The horizontal and vertical displacement in the dam after the Mar-Chile Earthquake in the
upper part of the downstream slope are, respectively, 2.0 and 1.0 m; in the upper berm - 2.2 and
1.1 m; in the lower berm - 2.5 and 1.3 m and at the toe of the slope - 6.0 m and zero (Fig. 3.10).
The intensity of shear deformations (Figure 3.11) is concentrated in the narrow zone in the
lower part of the downstream slope of the dam.
Fig. 3.10. Horizontal (a) and vertical (b) displacements in Limon dam (82m) after Mar-Chile Earthquake
Fig. 3.11. Intensity of the shear deformations in Limon dam (82m) after the Mar-Chile Earthquake
Fig. 3.12. The time history of the residual horizontal (a) and vertical (b) displacements of the crest of
Limon dam (82 m) during the Mar-Chile Earthquake
15. The time history of the residual horizontal (a) and vertical (b) displacements of the dam crest
during the Mar-Chile Earthquake is shown in Figure 3.12. The maximum horizontal and vertical
displacements of the dam crest during the Mar-Chile Earthquake are, respectively, 1.5 and 1.1 m
Conclusions
1. Horizontal and vertical displacements after the Mar-Chile Earthquake of the downstream slope
(between the dam crest and lower berm) are, respectively, 2.0-2.5 and 1.0-1.3 m. The maximum
horizontal and vertical displacements of the dam crest during the Mar-Chile Earthquake are,
respectively, 1.5 and 1.1 m and after the Earthquake - 0.4 and 0.3 m. These displacements about
two times lower than those in the previous variant 1 of the dam with the downstream slope of
(V/H=1/1.7) and the under-laying rockfill without berms.
2. In comparison with the previous variant 1 of Limon dam (H=82 m) with the downstream slope
of (V/H=1/1.7) and the under-laying rockfill without berms this variant 2 of Limon dam (H=82
m) with additional gravel zone with two berms on downstream slope is much more stable and
safe under action of very strong MCE of the Mar-Chile Earthquake. Therefore, this variant 2 of
Limon dam can be adopted in the following detailed final design of 82 m high CFRD Limon.
4. Example of dynamic analysis of 150 m high CFRD
As an example the dynamic analysis of 150 m high CFRD with upstream and downstream
slopes 1.5H/1V is considered.
Fig. 4.1 shows 3D model of the system dam-foundation and its discretization by finite elements.
Totally about 150 thousand finite elements, mainly 3D elements with 8-nodes and partially 3D
elements with 6-nodes in dam contact with abutments. Concrete face is simulated by 3D shell
elements. On face-dam contacts, in the deformation joints of face, on face-abutments contacts
one-sided links (contact works only in compression) are organized, taking into account the
friction on the contact surfaces. Some researches were previously specified on 2D models.
Fig. 4.1. 3D model of dam for analysis of 3D
stress-strain state:
1 - concrete face; 2 - rockfill; 3 - loose layer;
4 – foundation massif
Special combination of loads is considered:
hydro-static pressure of reservoir, dead weight of the dam (the initial stress state) and seismic
load in the form of three-component accelerograms applied to the lower surface of foundation
massif. Rockfill and transition zone materials are considered as a linear-elastic, nonlinear elastic
and elastic-plastic medium.
Fig. 4.3 shows the development of detachment (separationt) of the dam with face from both
abutment slopes. The upper figure shows the detachment of the dam and face from the left
abutment slope after 8 seconds of the earthquake. As can be seen from the lower figure, after
11.4 seconds of the earthquake detachment is observed only on the right abutment slope in the
central section of the dam (approximately under its crest).
16. Fig. 4.3. Deformations of the dam during seismic load
a - upstream view, t=8 sec; b - deformations of the central longitudinal section of the dam,
t=11.4 sec.
Fig. 4.4 shows the openings of face joints under static loads and after 8 sec. and 8.6 sec. of
earthquake.
Fig. 4.4. Openings of joints of concrete face:
a - under static load; b - under earthquake action in zone A of face after t=8 sec;
b - under earthquake action in zone A of face after t=8 sec.
It should be noted that implementation of full computational studies required to obtain enough
reliable dam response, required high qualification of researchers and appropriate computational
and technical support.
5. Prospects of construction of high CFRDs in Russia
Analysis of intensive construction of high CFRDs in China, Brazil, Colombia and some other
countries and experience of their operation have shown that under certain natural conditions
(favorable topographic and geotechnical conditions, availability of the necessary constructional
materials, etc.) the choice of this type of dam compared with the other type (rockfill dams with
clay or asphaltic concrete cores, RCC or concrete dams) can be the most efficient and
economical solution. This is due to the much smaller volume of rockfill materials, hydraulic
17. safety of CFRD with high piping resistance, static and seismic stability and effective compaction
of its rockfill and transition zones, concrete plinth and faces, retaining wall on dam crest.
According to long-term plan of the development of hydropower industry in Russia up to 2020
the main regions for construction of new hydropower plants are the North Caucasus, Altai,
Siberia and the Far East. Natural conditions for the construction of CFRs in the North Caucasus
are close enough to those conditions in which a large number of foreign CFRDs were
constructed. Therefore, CFRDs dams may be atractive especially in the Northern Caucasus and
some CIS countries (Tajikistan, Kirgizstan, Uzbekistan and Kazakhstan).
As for the construction of CFRDs in Siberia and the Far East some additional problems may
arise with regard to the concrete face behavior in its upper part under action of extreme low
temperatures. However, the experience of construction of 200 m high CFRD in Iceland shows
the ability to solve these problems.
On other side, the experience of construction of rockfill dams with asphaltic concrete cores in
Siberia, Norway and Canada shows that these dams are safer than CFRD in severe climate of
these countries.