Concrete Face Rockfill Dams Design, Construction, and Performance: Proceedings of a Symposium
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Effect of imperfect knowledge of hazards on the reliability of concrete face rockfill dam and breakwater. Full Text Available A formulation to treat aleatory and epistemic uncertainties, in a separate way, on infrastructures is proposed and applied to a dam and a breakwater in Mexico. The purpose of that is to de termine 2nd order bounds on the reliability estimation due to the in complete knowledge of some design parameters. These bounds provide a quantitative basis for risk management according to the risk—aversion of owners and operators of the infrastructure.
Also, acceptable values of reliability, are assessed in terms of consequences costs, and an initial cost curve for a breakwater is presented, as they may contribute to enhance the decision making process. The in corporation of epistemic uncertainty makes the reliability index to become a random variable and its his to gram is obtained to estimate percentiles as a means to measure a new additional room for decisions as compared to the traditionally used mean value of the reliability.
Conservative decisions are illustrated for design and assessment of structures like a dam and a breakwater. The procedure involves a double loop of Monte Carlo simulation and represents a basis for the optimal design and risk management of dams and breakwaters. This is a new damage pattern and did not occur in previous seismic damage investigation. Slabs dislocation will affect the seepage control system of the CFRD gravely and even the safety of the dam. In this study, based on the previous studies by the authors, the slabs dislocation phenomenon of the Zipingpu CFRD was investigated.
The procedure and constitutive model of materials used for finite element analysis are consistent.
The water elevation, the angel, and the strength of the construction joints were among major variables of investigation. The results indicated that the finite element procedure based on a modified generalized plasticity model and a perfect elastoplastic interface model can be used to evaluate the dislocation damage of face slabs of concrete faced rockfill dam during earthquake. The effects of the water elevation, the angel, and the strength of the construction joints are issues of major design concern under seismic loading.
Investigation on the temperature of the asphalt- concrete facing of embankment dams. Full Text Available Asphalt concrete is a traditional material used for the constructions of upstream sealing of reservoir dams , particularly in upper reservoirs of pumped storage hydroelectric plants. The asphalt layer is often exposed to significant fluctuations of temperature caused, for example, by heating the facing from the sun and by its subsequent rapid cooling by water during reservoir periodical filling.
To better understand the physical phenomena and behaviour of the facing in terms of vapour diffusion, the state of stress, etc. This paper describes the measurement of temperature in the asphalt facing of the Dlouhe Strane pumped storage hydroelectric plant and its evaluation using 1D numerical model of heat flow in the asphalt concrete facing. Numerical simulation for selected load scenarios enabled the temperature phenomena that take place in the construction of the asphalt- concrete facing to be quantified.
The analysis shows that during insolation, the asphalt facing is exposed to the significant temperature rise on its surface and also over its whole thickness. Similarly during frost weather the facing becomes frozen in its entire thickness. During the day cycle the temperature in the asphalt layers changes significantly. However, the temperature in the underlying rockfill dam body becomes steady approximately at the depth of 1. Keywords: Asphalt concrete facing , Temperature distribution analysis, Embankment dam.
Hydraulic fracturing of rock-fill dam. Full Text Available The condition in which hydraulic fracturing in core of earth-rock fill dam maybe induced, the mechanism by which the reason of hydraulic fracturing canbe explained, and the failure criterion by which the occurrence of hydraulicfracturing can be determined, were investigated. The mechanism of hydraulic fracturing can be explainedby fracture mechanics. Based on testingresults of a core soil, a new criterion for hydraulic fracturing was suggested,from which mechanisms of hydraulic fracturing in the core of rock-fill damwere discussed.
The results indicated that factors such as angle betweencrack surface and direction of principal stress, local stress state at thecrack, and fracture toughness KIC of core soil may largely affect theinduction of hydraulic fracturing and the mode of the propagation of thecrack. The condition in which hydraulic fracturing in core of earth-rock fill dam maybe induced, the mechanism by which the reason of hydraulic fracturing canbe explained, and the failure criterion by which the occurrence of hydraulicfracturing can be determined, were investigated.
Based on testingresults of a core soil, a new criterion for hydraulic fracturing. Study of flow rate across alluvial deposits in rockfill dams. The hydraulic behaviour of the till core of the LG-4 main dam at the James Bay hydroelectric development in northern Quebec, was simulated in order to explain the abnormally high pore pressures that have been observed in the downstream portion of cores in a number of earth and rockfill dams. Procedures followed and the hydraulic conductivities adopted in this study were outlined. Results of a comparison of the equipotential lines at the calculated piezometric heads with in-situ measurements were also provided.
Full Text Available There was studied the stress-strain state of m high rockfill dam where the seepage-control element is presented by a reinforced concrete face of soil-cement concrete placed on the under-face zone. Calculations were carried out for two possible variants of deformability of rock outline taking into account the non-linearity of its deformative properties.
It was obtained that the reinforced concrete face and the soil-cement concrete under-face zone work jointly as a single construction - a double-layer face. As the face assembly resting on rock is made with a sliding joint the scheme of its static operation is similar to the that of the beam operation on the elastic foundation.
At that, the upstream surface of the double-layer face is in the compressed zone and lower one is in the tensile zone. This protects the face against cracking on the upstream surface but threatens with structural failure of soil-cement concrete. In order to avoid appearance of cracks in soil-cement concrete part due to tension it is necessary to achieve proper compaction of rockfill and arrange transverse joints in the double-layer face.
Full Text Available Compaction quality control in filling construction is of great significance to the stability and durability of the face rockfill dam. The conventional method of quality control mainly relies on manual process control and inspection for a limited number of test holes, which cannot meet the high requirements of modern mechanized construction and schedule anymore, with increasing of scale of face rockfill dams.
Monitoring and surveillance of embankment dams - Geotechnical Engineering of Dams - page
There is an urgent need to propose a new quality control method of face rockfill dams during the entire compaction process. In this paper, a supervisory system based on GNSS Global Navigation Satellite System technology, wireless data communication technology, Internet of things technology, and computer technology is developed to supervise the real-time roller compaction parameters of the working surface including rolling track, rolling times, rolling speed, thickness, and smoothness.
The system obtains continuous and high-precision spatial position information of roller compaction machines through GNSS technology and then calculates the roller compaction parameter information. The compaction quality control for the face rockfill dam is achieved through the supervision of roller compaction parameters. The feasibility and robustness of the developed supervisory system are validated by a case study in the face rockfill dam of Shuibuya project in China. The practice shows that the system provides a new and effective method of process control for the construction quality of the roller compaction in dam engineering and realizes real-time, precision, and automatic supervising of roller compaction parameters and ensures better construction quality.
Seismic response of three-dimensional rockfill dams using the Indirect Boundary Element Method. The IBEM is based on a single layer integral representation of elastic fields in terms of the full-space Green function, or fundamental solution of the equations of dynamic elasticity, and the associated force densities along the boundaries. The method has been applied to simulate the ground motion in several configurations of surface geology.
Moreover, the IBEM has been used as benchmark to test other procedures. We compute the seismic response of a three-dimensional rockfill dam model placed within a canyon that constitutes an irregularity on the surface of an elastic half-space. The rockfill is also assumed elastic with hysteretic damping to account for energy dissipation. Various types of incident waves are considered to analyze the physical characteristics of the response: symmetries, amplifications, impulse response and the like.
Computations are performed in the frequency domain and lead to time response using Fourier analysis. In the present implementation a symmetrical model is used to test symmetries. The boundaries of each region are discretized into boundary elements whose size depends on the shortest wavelength, typically, six boundary segments per wavelength.
Usually, the seismic response of rockfill dams is simulated using either finite elements FEM or finite differences FDM. In most applications, commercial tools that combine features of these methods are used to assess the seismic response of the system for a given motion at the base of model. However, in order to consider realistic excitation of seismic waves with different incidence angles and azimuth we explore the IBEM. Full Text Available Monitoring data on an earth- rockfill dam constitutes a form of spatial data. Such data include much uncertainty owing to the limitation of measurement information, material parameters, load, geometry size, initial conditions, boundary conditions and the calculation model.
So the cloud probability density of the monitoring data must be addressed. In this paper, the cloud theory model was used to address the uncertainty transition between the qualitative concept and the quantitative description. Then an improved algorithm of cloud probability distribution density based on a backward cloud generator was proposed. This was used to effectively convert certain parcels of accurate data into concepts which can be described by proper qualitative linguistic values.
The algorithm was then applied to analyze the observation data of a piezometric tube in an earth- rockfill dam. And the damage of the seepage in the body was able to be found out. Discrete modelling of rock-fill : Application to dams ; Modelisation discrete des enrochements: Application aux barrages.
In this study, a discrete numerical model for rock-fill is built up and validated. This model is based upon the definition of bidimensional clusters that can break in different ways. The resistance of the inner bonds of the clusters are calibrated by reproducing the size-dependant resistance of rock blocks submitted to crushing tests.
Numerical simulations of laboratory tests are performed on samples made of the different clusters. Tests on crushable clusters emphasize the utmost importance of particle crushing on the behaviour. A dam is modelled. The role of the placed-rock face on the stabilisation is underlined. The deformation of the dam during reservoir filling, as well as its good seismic behaviour is well reproduced by the model. The model makes it possible to show the influence of particle breakage on the settlements.
Turkey has dams constructed between and for the purposes of irrigation, flood control, hydroelectric energy and drinking water. A major portion of the dam basins in Turkey are deprived of vegetation and have slope topography on near surrounding area. However, landscaping covered with forest around the dam basin is desirable for erosion control.
In fact; the dams , have basins deprived of vegetation, fill up quickly due to sediment transport. Erosion control and forestation are important factors, reducing the sediment, to protect the water basins of the dams and increase the functioning life of the dams. The functioning life of dams is as important as the investment and construction.
Nevertheless, in order to provide safety of human life living around, well planned monitoring is essential for dams. Dams are very large and critical structures and they demand the use or application of precise measuring systems. Some basic physical data are very important for assessing the safety and performance of dams.
These are movement, water pressure, seepage, reservoir and tail-water elevations, local seismic activities, total pressure, stress and strain, internal concrete temperature, ambient temperature and precipitation. Considering the time and labor consumed by long-term measurements, processing and analysis of measured data, importance of the small structural motions at regular intervals could be comprehended. This study provides some information, safety and the techniques about the deformation monitoring of the dams , dam safety and related analysis.
Brief information is given about the. Full Text Available Nonlinear elastic model and elastoplastic model are two main kinds of constitutive models of soil, which are widely used in the numerical analyses of soil structure. In this study, Duncan and Chang's EB model and the generalized plasticity model proposed by Pastor, Zienkiewicz, and Chan was discussed and applied to describe the stress-strain relationship of rockfill materials.
The two models were validated using the results of triaxial shear tests under different confining pressures. The comparisons between the fittings of models and test data showed that the modified generalized plasticity model is capable of simulating the mechanical behaviours of rockfill materials. The modified generalized plasticity model was implemented into a finite element code to carry out static analyses of a high earth- rockfill dam in China. Nonlinear elastic analyses were also performed with Duncan and Chang's EB model in the same program framework.
Full Text Available It is important to determine the seepage field parameters of a high core rockfill dam using the seepage data obtained during operation. For the Nuozhadu high core rockfill dam , a back analysis model is proposed using the radial basis function neural network optimized using a particle swarm optimization algorithm PSO-RBFNN and the technology of finite element analysis for solving the saturated-unsaturated seepage field. The recorded osmotic pressure curves of osmometers, which are distributed in the maximum cross section, are applied to this back analysis.
The permeability coefficients of the dam materials are retrieved using the measured seepage pressure values while the steady state seepage condition exists; that is, the water lever remains unchanged. Meanwhile, the parameters are tested using the unstable saturated-unsaturated seepage field while the water level rises. The results show that the permeability coefficients are reasonable and can be used to study the real behavior of a seepage field of a high core rockfill dam during its operation period.
Construction control for earth and rockfill dams. Technical engineering and design guides as adapted from the U. Army Corps of Engineers, No. This manual outlines the key components that will ensure the safety and performance of these dams , including competent and adequate supervision, careful inspection and control testing. Detailed chapters cover every aspect of foundation and abutment treatment, field organization and responsibility, borrow areas and quarries, earth-fill and rockfill construction, and miscellaneous construction features such as river diversion, stage construction and service bridge pier foundations.
Useful appendices contain methods for relating field density data to desired or specified values, field compaction control data, detailed information on instruments used in earth and rockfill dam construction and lists of required and related publications, as well as a bibliography. This detailed and useful manual is an essential information source for engineers and constructors. Dynamic probability evaluation of safety levels of earth- rockfill dams using Bayesian approach. Full Text Available In order to accurately predict and control the aging process of dams , new information should be collected continuously to renew the quantitative evaluation of dam safety levels.
Owing to the complex structural characteristics of dams , it is quite difficult to predict the time-varying factors affecting their safety levels. It is not feasible to employ dynamic reliability indices to evaluate the actual safety levels of dams. Based on the relevant regulations for dam safety classification in China, a dynamic probability description of dam safety levels was developed.
Using the Bayesian approach and effective information mining, as well as real-time information, this study achieved more rational evaluation and prediction of dam safety levels. With the Bayesian expression of discrete stochastic variables, the a priori probabilities of the dam safety levels determined by experts were combined with the likelihood probability of the real-time check information, and the probability information for the evaluation of dam safety levels was renewed. The probability index was then applied to dam rehabilitation decision-making. This method helps reduce the difficulty and uncertainty of the evaluation of dam safety levels and complies with the current safe decision-making regulations for dams in China.
It also enhances the application of current risk analysis methods for dam safety levels. Seismic security assessment of earth and rockfill dams located in epicentral regions. Oldecop, L. Instituto de Invest. The seismic safety of dams is of great interest to the midwest region of Argentina, the most seismically active area in the country. This paper examines factors controlling the design of dams subjected to earthquake action, criteria for safety verification and the analysis tools currently available. Data of dams , active faults and epicenters of historic earthquakes in the region were provided.
Paleoseismicity research was suggested as an important area of research, potentially enhancing an understanding of a region's seismic activity. It was concluded that analysis tools currently used in engineering include simple models offering advantages in reliability and ease of result interpretation, but have shortcomings in their applicability. Care must be taken in the validation and interpretation of these models, particularly when the behaviour of a dam includes complex phenomena.
More sophisticated analysis tools currently available are difficult to apply, largely due to the complexity of algorithms in the models.
It was also concluded that in order to overcome difficulties in both simple and complex models, predictions should be contrasted with real behaviour data. Data from measurement of seismic behaviour is still relatively scarce, presenting an obstacle towards the further use of more sophisticated analysis tools, as they are not as yet tested against measurements and observations of real cases. Effects of particle size and confining pressure on breakage factor of rockfill materials using medium triaxial test.
Full Text Available Rockfill dams are mostly constructed using blasted rockfill materials obtained by blasting rocks or alluvial rockfill materials collected from the riverbeds. Behaviors of rockfill materials and their characterization significantly depend on breakage factor observed during triaxial loading. In this paper, two modeled rockfill materials are investigated by using medium triaxial cell.
Drained triaxial tests are conducted on various sizes of modeled rockfill materials used in the two dams , and test data are analyzed accordingly. Breakage factor of rockfill material is studied and the effects of particle size and confining pressure on breakage factor are investigated using medium triaxial cell as many researchers have already conducted investigation using large triaxial cell.
Evaluation of behaviors of earth and rockfill dams during construction and initial impounding using instrumentation data and numerical modeling. Full Text Available In this study, the behavior of Gavoshan dam was evaluated during construction and the first impounding. A two-dimensional 2D numerical analysis was conducted based on a finite difference method on the largest cross-section of the dam using the results of instrument measurements and back analysis. These evaluations will be completed in the case that back analysis is carried out in order to control the degree of the accuracy and the level of confidence of the measured behavior since each of the measurements could be controlled by comparing it to the result obtained from the numerical model.
Following that, by comparing the results of the numerical analysis with the measured values, it is indicated that there is a proper consistency between these two values. Moreover, it was observed that the dam performance was suitable regarding the induced pore water pressure, the pore water pressure ratio ru, settlement, induced stresses, arching degree, and hydraulic fracturing probability during the construction and initial impounding periods.
The reason is that the clay core was smashed in the wet side, i. Whereas the average curving ratio was 0. It was also concluded that this dam is safe in comparison with the behaviors of other similar dams in the world. Effects of a thin liquefiable foundation layer on deformations of a rockfill dam subjected to earthquake shaking.
Seid-Karbasi, M. This paper discussed a coupled stress-flow dynamic analysis procedure designed to predict the stability and seismic deformations of an 85 meter high earth dam located near a polymetallic mine in Vietnam. The procedure was developed to capture sand element behaviours observed in previous laboratory tests. Both models were incorporated within the FLAC model. Dam specifications, foundation characteristics, and predicted behaviours were discussed. The dam body and its foundation were analyzed under gravity loads with drained conditions in order to establish the pre-earthquake stress state.
A dynamic analysis was then conducted using undrained properties for fine-grained soils. The FLAC model finite difference analysis was used to examine stress-flow under static and dynamic loading conditions. Earthquake motions were applied as a time history of excitation at the model's boundaries. Volumetric strains were controlled by the compressibility of the pore fluid and the flow of water through the soil elements. The model was calibrated using laboratory and centrifuge data.
Results of the study showed that the tailings and downstream free-field alluvial soils developed high excess pore water pressures and liquefied during strong shaking motions. Results suggested that the seismic performance of the Oxide dam were satisfactory. Full Text Available The article deals with the dam site shape effect produced on values of displacements in the perimeter joint of the m high rockfill dam having a reinforced concrete face.
Six alternative options of the dam site were considered: 3 sites having trapezoidal shape and 3 sites having triangular shape. The options also differ in slopes of rock sides , , Displacements in a perimeter joint were identified based on the analyses of stress-strain states of rockfill dams , completed using the method of contact finite element to model the behaviour of joints. In the course of the modeling process, the perimeter joint opened in all six options, because horizontal displacements of the face in the direction along the river channel turned to be approximately equal to its settlement.
In case of narrow triangular sites, the maximal opening of the joint occurs on the rock sides. In case of wide sites, opening at low levels increases to a considerable extent; large openings are observed not only on dam sides, but in the river channel, as well. An opening of the perimeter joint means reduction of values of tensile forces on the face. If the perimeter joint opens, the face is free to move in other directions. Deflections may reach large values, especially if the dam site is wide and has steep rock sides. Deflections reach maximum values in the points, where the reinforced concrete face demonstrates its maximum deflection.
The studies prove that the width of the dam part in the river channel has the major effect on values of displacements in the perimeter joint. Discrete element simulation of crushable rockfill materials. Full Text Available A discrete element method was used to study the evolution of particle crushing in a rockfill sample subjected to triaxial shear.
A simple procedure was developed to generate clusters with arbitrary shapes, which resembled real rockfill particles. A theoretical method was developed to define the failure criterion for an individual particle subjected to an arbitrary set of contact forces. Then, a series of numerical tests of large-scale drained triaxial tests were conducted to simulate the behaviors of the rockfill sample. Finally, we examined the development of micro-characteristics such as particle crushing, contact characteristics, porosity, deformation, movement, and energy dissipation.
The simulation results were partially compared with the laboratory experiments, and good agreement was achieved, demonstrating that the particle crushing model proposed can be used to simulate the drained triaxial test of rockfill materials. Based on a comparison of macro behaviors of the rockfill sample and micro structures of the particles, the microscopic mechanism of the rockfill materials subjected to triaxial shear was determined qualitatively. It is shown that the crushing rate, rather than the number of crushed particles, can be used to reflect the relationship between macro- and micro-mechanical characteristics of rockfill materials.
These research results further develop our understanding of the deformation mechanism of rockfill materials. Analysis of the behaviour of embankment dams during and after impoundment; Analyse du comportement de barrages en remblai pendant et apres leur mise en eau. Massiera, M. This paper analyzed the behaviour of 2 embankment dams during impoundment. The study compared the values of the observed and calculated displacements of the crest during the initial filling of the reservoirs at the zoned earth West Dam in California and the Tounustouc concrete face rockfill dam CFRD in Quebec.
The calculations were performed using finite element analysis. Rock and earthfill dams constructed on moraine deposits are known to deform under the influence of water load as the reservoir is filled. Therefore, this study also analyzed the long term deformations of the West Dam during 4 subsequent years of operation of the reservoir. Modelling rock and earthfill dams takes into account the nonlinear behaviour of the construction materials; interaction between the structure and the underlying soil and rock strata; influence of water load on the structure and on the foundation bedrock; and the effects of water saturation.
This paper showed that geotechnical and geodetic monitoring may provide a warning system in case of abnormal behaviour of the embankment dam. In tectonically active zones, monitoring surveys may also provide information on the effects of seismic disturbances. Full Text Available Compaction quality is directly related to the structure and seepage stability of a rockfill dam. To timely and accurately test the compaction quality of the rockfill material, four real-time test indexes were chosen to characterize the soil compaction degree based on the analysis of roller vibratory acceleration, including acceleration peak value ap, acceleration root mean square value arms, crest factor value CF, and compaction meter value CMV.
To determine which of these indexes is the most appropriate, a two-part field compaction experiment was conducted using a vibratory roller in different filling zones of the dam body. Data on rolling parameters, real-time test indexes, and compaction quality indexes were collected to perform statistical regression analyses. Combined with the spectrum analysis of the acceleration signal, it was found that the CF index best characterizes the compaction degree of the rockfill material among the four indexes.
Furthermore, the quantitative relations between the real-time index and compaction quality index were established to determine the control criterion of CF, which can instruct the site work of compaction quality control in the rockfill rolling process. War damages and reconstruction of Peruca dam. The paper describes the heavy damages caused by blasting in the Peruca rockfill dam in Croatia in January Complete collapse of the dam by overtopping was prevented through quick action of the dam owner by dumping clayey gravel on the lowest sections of the dam crest and opening the bottom outlet of the reservoir, thus efficiently lowering the water level.
After the damages were sufficiently established and alternatives for restoration of the dam were evaluated, it was decided to construct a diaphragm wall through the damaged core in the central dam part as the impermeable dam element and to rebuild the central clay core at the dam abutments. Reconstruction works are described. Mechanics of slide dams. Studies which promote the use of nuclear energy for peaceful projects in engineering are sponsored by the Atomic Energy Commission under the Plowshare program.
Specific projects being considered include the construction of harbors, canals, and dams. Of these projects, perhaps the most difficult to accomplish will be the latter. This paper which is in two parts considers the problems which are associated with the construction of slide dams with nuclear explosives.
It examines first the characteristics of conventional earth and rock-fill dams which are based upon proven techniques developed after many years of experience. The characteristics of natural landslide dams are also briefly considered to identify potential problems that must be overcome by slide dam construction techniques. Second, the mechanics of slide dams as determined from small-scale laboratory studies are presented.
It is concluded that slide dams can be constructed and that small-scale field tests and additional laboratory studies are justified. Odelouca Dam Construction: Numerical Analysis. Odelouca dam is an embankment dam , with 76 m height, recently constructed in the south of Portugal. It is zoned with a core consisting of colluvial and residual schist soil and with soil- rockfill mixtures making up the shells weathered schist with a significant fraction of coarse sized particles.
The material con-stants of the soil model used are determined from a comprehensive testing programme carried out in the C Estimation of permanent displacements of the Tehri dam in the Ambraseys N, Jackson D A note on early earthquakes in northern india Two types of drained triaxial tests on NRFM were conducted, namely, the stress paths of constant stress ratio CSR and the complex stress paths with transitional features. The model was improved by considering the interparticle parameter variation with the unloading-reloading cycles and the effect of the stress transition path.
The evolution of local dilatancy at interparticle planes due to an externally applied load is also discussed. All simulations have demonstrated that the proposed M-A model is capable of modelling the mechanical behaviour of NRFM in the dam. It is zoned with a core consisting of colluvial and residual schist soil, and with soil- rockfill mixtures making up the shells weathered schist with a significant fraction of coarse sized particles. This paper presents a numerical analysis of Odelouca dam construction. In this analysis the explicit finite difference program FLAC is used.
An unconventional elastoplastic soil model, a Subloadin The author of ''Silenced Rivers'' a book questioning the desirability of dam building and hydroelectric power generation argues the main themes of his book in this paper. Despite being hailed by politicians as good solutions to power generation problems, and enthusiastically pursued in China, the U. The ecosystems lost to flooding, and the agricultural land use lost, the human cost in terms of homes and employment lost to reservoirs, disease from water-borne infections such as malaria, and the hazards of dams overflowing or breaking are all factors which are against the case for dam construction.
The author argues the hydroelectric power may be renewable, but the social, agricultural and ecological costs are too high to justify it as a method of first choice. The first cut-off wall in the Indian Himalayas for the dam of the Dhauliganga hydroelectric project. This paper provided details a Bauer cutter used to build a cut-off wall for the Dhaulinganga power plant project in the Himalayan mountains. The dam for the project was built as a 56 m high concrete-faced rockfill dam with a length of m at the crown.
A cut-off wall was constructed on the upstream side of the dam extending down from the dam 's plinth to the bedrock level. A Bauer cutter was used to key the cut-off wall straight into the bedrock, which omitted the need for a grout curtain. The wall was constructed as a series of primary and secondary panels. Excavation of the panels was carried out in single bites by the Bauer DHG hydraulic diaphragm wall grabs, supported a box chisel, cross chisel and a Bauer BC 40 rock cutter.
Trench stability was provided by bentonite slurry. The closing forces were activated by a cylinder which was installed vertically inside the base body. The Bauer cutter continuously removed soil and rock from the bottom of the trench for mixing with the bentonite slurry.
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The slurry was then pumped through a ring main of hose pipes to a desanding plant where it was cleaned and returned to the trench. Advantages offered by using the cutter included a consistently high output, an extremely high degree of verticality, watertight joints, and the ability to cut through hard boulders. Use of the cutter at the Dhaulinganga site showed that the project could not be carried out successfully without the use of the cutter, which was used whenever grab and chisel methods were unable to achieve satisfactory rates of penetration.
Deployment of the cutter was essential to key the cut-off wall into the underlying bedrock. It was concluded that the Dhualinganga project will provide a model for future power generation projects in the Indian Himalayas. Matahina Dam : lessons learned from an earthquake-related internal erosion incident at the Matahina Dam , New Zealand.
This case history discussed internal erosion damage and crest subsidence caused by an earthquake at the Matahina Dam in New Zealand. The study showed that cracking and internal erosion was initiated during the reservoir filling operation. Located in an area of active volcanism and faulting, the dam is located on a river with extensive erosion through an ignimbrite flow. The dam 's core is founded on compact Tertiary age sediments overlain by sand and gravel deposits beneath the shoulders of the dam. The earthquake caused a rupture along an unidentified fault trace 12 km from the dam.
The horizontal base acceleration recorded at the dam was 3. Transverse cracking was observed at each abutment, and deformations were observed in the rockfill. An investigation program was conducted to determine the dam 's integrity. Piezometer measurements showed widespread fluctuations. It was concluded that the lack of an effective filter was a significant design omission.
Thermal monitoring of leakage through Karkheh embankment dam , Iran. Mirghasemi, A. A newly developed and simple method for monitoring seepage in embankment dams was presented.1stclass-ltd.com/wp-content/require/1845-telefon-abhoeren.php
Earth / Rockfill Dams
The method of temperature measurement is based on the fact that a change in permeability results in a change in seepage flow, thereby causing a temperature change that can be readily measured in the dam body and foundation. In this study, water leaking through the Karkheh embankment dam was thermally analyzed to determine a pattern and amount of water seepage. With nearly 33 million cubic metres of fill, the Karkheh earth and rock-fill dam is the largest dam in Iran. Construction was completed in The thermal processes in the embankment were studied due to the dam 's complex thermo-hydraulic behaviour.
Thermal data was collected and analyzed during construction and operation of the dam. This paper presented the temperature variations for the different dam zones, including core, upstream shell, downstream shell, upstream filter, downstream filter and the plastic concrete cut-off wall. It was determined that the clay core works very well as an impermeable curtain. It was also shown that temperature variations of the Karkheh reservoir water is seasonal, and decrease as water depth increases.
The reservoir water temperature remains constant beyond depths of 60 metres. The thermal behaviour of the core is not similar to that of the reservoir, indicating a very low value of seepage through the core. The pattern of temperature variations in the upstream shell in the left abutment is harmonic, while in the right abutment it is not harmonic. A harmonic pattern of temperature variation exists in some aquifers of the dam foundation, indicating high seepage through these aquifers.
The Karkheh dam cut-off wall performs satisfactorily. It was determined that one dimensional equations for estimating seepage cannot be applied for the Karkheh dam. The underwater installation of a drained geomembrane system on Lost Creek Dam. Lost Creek Dam was constructed in California around It is a foot high concrete arch dam with a crest elevation of 3, feet and a crest length of feet.
Over the years, the dam and the condition of the concrete face have deteriorated. The concrete is porous and seeps water along the entire downstream face. In winter, the seeping water freezes, penetrates the concrete and causes expansion and spalling of the concrete surface. In some places, the concrete has very low strength to a depth of a foot or more, rendering the dam only marginally safe. Seven mitigative measures were identified as possible solutions to the problem.
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It was determined that the seepage of the water through the concrete dam could be stopped with the installation of a geomembrane to the upstream face. This paper describes the unique underwater installation of a drained geomembrane system on the concrete face of the dam. This was the first ever installation of a drained geomembrane system on an entire dam using divers. Monitoring will determine the success of the project, and whether the seepage of the water through the porous concrete had been reduced sufficiently to stop the deterioration of the concrete on the downstream face.
Abstracts and electronic proceedings of the Canadian Dam Association's annual conference : protecting people, property and the environment; Resumes et actes electroniques du congres annuel de l'Association canadienne des barrages : proteger les personnes, les biens et l'environnement. This annual conference provided a professional development opportunity on a broad range of dam -related topics.
The technical sessions addressed issues such as adaptation to climate change; the application of safety design for discharge facilities; risks associated with rockfill dams ; underlying problems of design floods and dam safety; guidelines for public safety around dams and psychology of safety; the dam safety review process; and run-of-river hydro dams. The workshops focused on incident investigations; reliability-centered maintenance; flow discharge gate reliability; piping damage to till core dams ; and mining dams.
The sessions of the conference were entitled: design floods and dam safety; dam breach flood modelling; dam safety management; public safety; mining dams ; flood handling and modelling; case studies; ice loads on structures; seepage control; dam safety reviews and remediation; remote sensing for dams ; protecting the environment; seismic hazard and response modelling; and the performance of dams in earthquake in Sichuan, China. The conference featured 61 presentations, of which 59 have been catalogued separately for inclusion in this database.
Full Text Available A GCTS medium-sized triaxial apparatus is used to conduct a single-line method wetting test on three kinds of rockfill materials of different mother rocks such as mixture of sandstone and slate, and dolomite and granite, and the test stress conditions is the combination of spherical stress p and deviatoric stress q. The test results show that 1 for wetting shear strain, the effects of spherical stress p and deviatoric stress q are equivalent, and wetting shear strain and deviatoric stress q show the power function relationship preferably.
Also, the wetting strains will decrease with the increase in the saturated uniaxial compressive strength and average softening coefficient of the mother rock. Based on the test results, a wetting strain model is proposed for rockfill materials. The verification results indicate that the model satisfactorily reflects the development law of wetting deformation.
Design, construction and performance of the Oldman River Dam grout curtain. Hartmaier, H. The 76 m high Oldman River Dam was constructed between and near Pincher Creek, Alberta to provide flow regulation and on-stream storage of water for multi-purpose use and irrigation services as well as hydroelectric development. The grout curtain was built in undeformed Paleocene sedimentary rocks affected by stress relief due to river valley erosion. Piezometers, slope indicators and flow measurement weirs were installed in the dam and abutment areas both during and after construction to monitor the performance of the grout curtain.
Instrument readings indicate that the grout curtain is successfully preventing the transmission of reservoir pressures to the foundation beneath the downstream shell of the dam. The piezometric pressures downstream of the grout curtain are the same as they were in the foundation before impounding. A small amount of seepage has appeared at the end of the grout curtain at the eastern end of the abutment of the spillway but it is not considered to be significant. Behind an ambitious megaproject in Asia: The history and implications of the Bakun hydroelectric dam in Borneo. Sovacool, Benjamin K.
Using a case-study, inductive, narrative approach, this article explores the history, drivers, benefits, and barriers to the Bakun Hydroelectric Project in East Malaysia. Bakun Dam and its affiliated infrastructure could be the single largest and most expensive energy project ever undertaken in Southeast Asia. Based on data collected through site visits, original field research in Sarawak, and more than 80 research interviews, the article begins by teasing out the complex history and drivers behind the Bakun project before identifying a set of potential social, political, and economic benefits the project could deliver.
It then delves into six sets of barriers in the technical, economic, political, legal and regulatory, social, and environmental realms. We find that Bakun illustrates how centralized energy megaprojects, while ostensibly championed for reasons of economies of scale and the ability to bring about transformational change in the shortest period of time, often fail to address broader development goals such as fighting energy poverty and improving the livelihoods of the local communities they are supposed to serve.
Dam Safety Concepts. The majority of dams constructed in the world are dams that can be categorized as embankment dams. Throughout history we can point to many failures of dams , and embankment dams in particular. Nowadays it is clear that the goal to construct stable dams has not been achieved, even with advanced. Interpretation of self-potential data for dam seepage investigations. This book represents one of a series on the subject of geophysical methods and their use in assessing seepage and internal erosion in embankment dams. This manual facilitates the interpretation of self-potential SP data generated by subsurface fluid flow, with an emphasis on dam seepage studies.
It is intended for users with a background in geophysics or engineering having a general familiarity with both the SP and direct-current DC resistivity methods and their applications. It includes an extensive reference list covering all aspects of available SP interpretation techniques, including qualitative, analytical and numerical methods. Particular emphasis is placed on the use of geometric source analytical modeling methods to evaluate SP anomalies. These methods provide a simple yet efficient means of estimating the location and depth of current sources of observed SP data, which may be linked to fluid flow in the subsurface.
The manual is primarily oriented toward embankment dams and earthen structures such as levees and dikes. SP methods have been used to investigate seepage through pervious zones and cracks in concrete and concrete-faced structures. The manual describes the nature of SP fields generated by both uniform and non-uniform dam seepage flow, as well as non-seepage sources of SP variations. These methods enable the study of more complex systems and require a more comprehensive analysis of a given field site.
This article describes the actions taken to address an unusual amount of water seepage from the left abutment weir-box of the River Reservoir dam built in near Eagar, Arizona. Upon noting the seepage in March , the operator, Round Valley Water Users Association, contacted the State of Arizona who funded the investigation and subsequent remediation activities through an emergency fund.
The dam was originally built with local materials and did not include a clay core. It was modified at least four times. The embankment sits on basalt bedrock and consists of clayey soils within a rock-fill shell. AquaTrack technology developed by Willowstick Technologies was used to assess the deteriorating situation. AquaTrack uses a low voltage, low amperage audio-frequency electrical current to energize the groundwater or seepage. This made it possible to follow the path of groundwater between the electrodes.
A magnetic field was created which made it possible to locate and map the field measurements. The measured magnetic field data was processed, contoured and correlated to other hydrogeologic information. This identified the extent and preferential flow paths of the seepage. The survey pinpointed the area with the greatest leakage in both the horizontal and vertical directions. Fluorescent dyes were also used for tracer work to confirm previous findings that showed a serious seepage problem.
The water of the reservoir was lowered to perform remedial measures to eliminate the risk of immediate failure. Funding for a more permanent repair is pending.
- Die Fledermaus (Opera Journeys Mini Guide);
- European Identity in Cinema (Intellect Books - Changing Media, Changing Europe).
- Frames in the Toxicity Controversy: Risk Assessment and Policy Analysis Related to the Dutch Chlorine Debate and the Swedish PVC Debate.
- Concrete Face Rockfill Dams—Design, Construction, and Performance.
- The Sons of Bayezid: Empire Building and Representation in the Ottoman Civil War of 1402–1413 (The Ottoman Empire and its Heritage: Politics, Society and Economy);
- Concrete face rockfill dams hardcover;
- Freely available.
There are many problems in the construction of hydraulic structures on deep overburden because of its complex foundation structure and poor geological condition. Seepage failure is one of the main problems. The Combination of the seepage control system of the face rockfill dam and the deep overburden can effectively control the seepage of construction of the concrete face rockfill dam on the deep overburden.
Widely used anti-seepage measures are horizontal blanket, waterproof wall, curtain grouting and so on, but the method, technique and its effect of seepage control still have many problems thus need further study. Due to the above considerations, Three-dimensional seepage field numerical analysis based on practical engineering case is conducted to study the seepage prevention effect under different seepage prevention methods, which is of great significance to the development of dam technology and the development of hydropower resources in China.
NRC inventory of dams. The inventory lists 51 dams associated with nuclear power plant sites and 14 uranium mill tailings dams licensed by NRC in the US as of February 1, Of the 85 listed nuclear power plants units , 26 plants obtain cooling water from impoundments formed by dams. The 51 dams associated with the plants are: located on a plant site 29 dams at 15 plant sites ; located off site but provide plant cooling water 18 dams at 11 additional plant sites ; and located upstream from a plant 4 dams - they have been identified as dams whose failure, and ensuing plant flooding, could result in a radiological risk to the public health and safety.
The dams that might be considered NRC's responsibility in terms of the federal dam safety program are identified. This group of dams 20 on nuclear power plant sites and 14 uranium mill tailings dams was obtained by eliminating dams that do not pose a flooding hazard e. The report includes the principal design features of all dams and related useful information. Alpine dams. Mountain reservoirs were initially built in the Alps to meet energy needs in the winter.
A certain diversification in the uses of water then gradually developed, related to tourism development in the local communities. Today, the use of facilities belonging to EDF French Electricity Authority to provide water for winter resorts to make artificial snow represents a new phase. By taking water from EDF resources to supply snow-making equipment, resort managers are thus able to avoid the problems related to the construction and management of small headwater dams.
This new orientation in the use of mountain water resources already affects a number of alpine regions such as the Upper Maurienne valley and Beaufortain massif and represents a renewed form of the territorial integration of water resources. Construction of anhydrite dams. To construct a ventilation dam , the road is closed with a fibreglass sheet onto which 3 or 4 cm of anhydrite paste is sprayed.
The equipment necessary is described, and the cost is compared with that of an aggregate dam. Dam removal: Listening in. Foley, M. Dam removal is widely used as an approach for river restoration in the United States. The increase in dam removals—particularly large dams—and associated dam -removal studies over the last few decades motivated a working group at the USGS John Wesley Powell Center for Analysis and Synthesis to review and synthesize available studies of dam removals and their findings.
Based on dam removals thus far, some general conclusions have emerged: 1 physical responses are typically fast, with the rate of sediment erosion largely dependent on sediment characteristics and dam -removal strategy; 2 ecological responses to dam removal differ among the affected upstream, downstream, and reservoir reaches; 3 dam removal tends to quickly reestablish connectivity, restoring the movement of material and organisms between upstream and downstream river reaches; 4 geographic context, river history, and land use significantly influence river restoration trajectories and recovery potential because they control broader physical and ecological processes and conditions; and 5 quantitative modeling capability is improving, particularly for physical and broad-scale ecological effects, and gives managers information needed to understand and predict long-term effects of dam removal on riverine ecosystems.
Download Article PDF. Share this article. Article information. Author e-mails. Sherard J. Assessment J. Cooke J. Design J. Uddin N. Hunter G. Geoenviromental Eng. Kim Y. Modares M. Arici Y. Gergely P. Chen Y. Woo S. Zhang L. Wang K. Aldea C. Kachanov L. Mazars J. Jason L. Methods Appl. Giakoumelis G.
Steel Res. Sinha B. Sfer D. Pijaudier-Cabot G.