Gravity Dam Research Articles

Water Dams: From Ancient to Present Times and into the Future

Since ancient times, dams have been built to store water, control rivers, and irrigate agricultural land to meet human needs. By the end of the 19th century, hydroelectric power stations arose and extended the purposes of dams. Today, dams can be seen as part of the renewable energy supply infrastructure. The word dam comes from French and is defined in dictionaries using words like strange, dike, and obstacle. In other words, a dam is a structure that stores water and directs it to the desired location, with a dam being built in front of river valleys. Dams built on rivers serve various purposes such as the supply of drinking water, agricultural irrigation, flood control, the supply of industrial water, power generation, recreation, the movement control of solids, and fisheries. Dams can also be built in a catchment area to capture and store the rainwater in arid and semi-arid areas. Dams can be built from concrete or natural materials such as earth and rock. There are various types of dams: embankment dams (earth-fill dams, rock-fill dams, and rock-fill dams with concrete faces) and rigid dams (gravity dams, rolled compacted concrete dams, arch dams, and buttress dams). A gravity dam is a straight wall of stone masonry or earthen material that can withstand the full force of the water pressure. In other words, the pressure of the water transfers the vertical compressive forces and horizontal shear forces to the foundations beneath the dam. The strength of a gravity dam ultimately depends on its weight and the strength of its foundations. Most dams built in ancient times were constructed as gravity dams. An arch dam, on the other hand, has a convex curved surface that faces the water. The forces generated by the water pressure are transferred to the sides of the structure by horizontal lines. The horizontal, normal, and shear forces resist the weight at the edges. When viewed in a horizontal section, an arch dam has a curved shape. This type of dam can also resist water pressure due to its particular shape that allows the transfer of the forces generated by the stored water to the rock foundations. This article takes a detailed look at hydraulic engineering in dams over the millennia. Lessons should be learned from the successful and unsuccessful applications and operations of dams. Water resource managers, policymakers, and stakeholders can use these lessons to achieve sustainable development goals in times of climate change and water crisis.

Stability Analysis of Gravity Dam using Matlab Programming

Gravity dams are critical structures in civil engineering, designed to withstand the immense forces exerted by water pressure and gravity. Ensuring their stability is paramount to prevent catastrophic failures that could result in significant economic and environmental consequences. This study presents a comprehensive stability analysis of a gravity dam using MATLAB programming. The analysis focuses on evaluating the structural integrity and safety factors of the dam under various loading conditions, including hydrostatic pressure and seismic forces. MATLAB's computational capabilities are utilized to perform rigorous numerical simulations, incorporating finite element analysis (FEA) and stability criteria assessments. Key aspects of the stability analysis include the determination of critical failure modes such as sliding, overturning, and base pressure distribution. Through MATLAB programming, the study explores different dam geometries and material properties to assess their influence on overall stability. Furthermore, sensitivity analyses are conducted to investigate the impact of uncertainties in input parameters on the dam's stability margins. This provides insights into potential weak points and allows for optimization of design parameters to enhance dam safety.

Seismic Performance Evaluation of Concrete Gravity Dams Subjected to Mainshock and Aftershocks

Seismic Performance Evaluation of Concrete Gravity Dams Subjected to Mainshock and Aftershocks

Influence of Foundation Stiffness on the Fragility Curves of a Concrete Gravity Dam Subjected to Near-Field Ground Motions Using Finite Element Method

A concrete gravity dam is being investigated to determine the fragility curves during near-field ground motions under various foundation stiffness conditions. This is accomplished using the finite element method for modeling the Latyan dam and its dam-reservoir-bed complex interaction system. The nonlinear constitutive model of concrete, plastic damage, is used to simulate the cyclic behavior of tensile and compressive failures in concrete. An acoustic element is used to model the propagation of compressive waves in the reservoir to account for the hydrodynamic effects of the lake reservoir. A total of 100 real and scaled accelerograms are used to simulate near-filed seismic loading in eight different concrete-to-foundation stiffness ratios. Based on the peak ground acceleration (PGA) of the earthquake, numerical models are applied to obtain the probability density function (PDF) and cumulative distribution function (CDF) for lognormal distributions and to determine and analyze the fragility curves of the dam. According to the findings, the seismic performance of the dam is improved for stiffness ratios of 0.75, 1, and 1.5, and the best seismic performance is determined for stiffness ratios of 1. Concrete dams with stiffness ratios of 0.75, however, perform better when the peak ground acceleration is greater than 0.74g compared to those with stiffness ratios of 1. DOI: https://doi.org/10.52783/pst.502

Undertaking risk assessments for Hong Kong reservoirs

The 2013 RARS (risk assessments for reservoir safety management) guidance was developed for the Environment Agency to provide a robust three-tiered framework for the risk analysis, assessment and management of reservoirs in the United Kingdom. The methods presented can be used to assess a reservoir's risk in its entirety, either at a qualitative level (tier 1) or more in-depth quantitative levels (tiers 2 and 3). Binnies undertook RARS assessments of reservoirs for Hong Kong's Water Supply Department. This paper identifies the limitations and challenges encountered when applying the guidance in Hong Kong, beyond its original intended purpose. It outlines the adjustments made to assess the Hong Kong service reservoirs at tier 1, and large embankment and gravity dams at tier 2. Some of the differences include (i) how the nature of loading and external threats differs due to geographical and locational differences; (ii) how consequences of reservoir failure differ due to topology, population densities and cultural differences in the reservoirs’ uses and (iii) how the reservoirs are atypical from ‘Pennine’ type UK embankment dams, from which most UK empirical methods are derived.

Phase-field modelling of dynamic hydraulic fracturing in porous media using a strain-based crack width formulation

This paper presents a comprehensive study on phase-field modelling in COMSOL MultiPhysics for simulating dynamic hydraulic fracturing in porous media based on Biot’s poro-elasticity theory. The focus is on addressing the challenges associated with crack width estimation in this context. A new strain-based crack width formulation is proposed, offering improved accuracy in predicting fracture permeability and ease of implementation in numerical approaches. The model’s capabilities are extended to consider dynamic crack propagation by incorporating the kinetic energy in the governing coupled hydro-mechanical-damage equations. The numerical implementations in COMSOL MultiPhysics are thoroughly explained, providing insights into the techniques used to solve the governing equations. Verification examples, including the benchmark KGD verification, are presented to demonstrate the model’s capabilities in simulating hydraulic fractures in porous media and validate its accuracy and reliability. A final numerical example focusing on the dynamics of crack propagation in a gravity dam is simulated, allowing for a comprehensive examination of the model’s performance. The proposed strain-based crack width formulation and consideration of dynamic crack propagation contribute to improved accuracy in predicting fracture permeability.

Response spectrum and modal dynamic analyses of gravity dams using ground motion accelerations modified to account for hydrodynamic effects

This research proposes simplified methods for response spectrum and modal dynamic analyses of gravity dams using time-history and spectral seismic accelerations modified to directly account for hydrodynamic effects. The developed methods waive the need for specialized fluid-structure interaction software. They also lead to more accurate assessment of coupled structural flexibility and hydrodynamic effects due to each vibration mode than the static correction method commonly used in traditional simplified methods. The methodology utilizes analytical formulations of hydrodynamic pressure or simplified added masses to obtain the contributions of the selected vibration modes to the total seismic response. A hydrodynamic modification factor characterizing the amplification/de-amplification of acceleration seismic demands due to earthquake-induced hydrodynamic effects is also introduced. The application of the proposed methods is illustrated numerically through examples of two typical gravity dam-reservoir systems subjected to four earthquakes. The obtained results are in excellent agreement with the classical reference solutions. Time-history and spectral seismic acceleration demands modified by hydrodynamic effects as well as selected key response indicators, such as relative displacements and stresses within the studied gravity dams, are discussed.

REVIEW OF STRUCREVIEW OF STRUCTURAL DEVELOPMENT OF DAMS WITH AN EMPHASIS ON THE CONSTRUCTION OF THREE GORGES DAMTURAL DEVELOPMENT OF DAMS WITH AN EMPHASIS ON THE CONSTRUCTION OF THREE GORGES DAM

<p>Dams are hydrotehnic engineering structures that have undergone significant advancement throughout history from an engineering standpoint, and today they represent some of the most complex constructions. Additionally, they play a crucial role in the economic development of many countries. Four basic types of dams have been developed: embankment, gravity, buttress, and arch dams. Each of them poses unique challenges that require significant efforts from engineers, which include the constant development and application of new technologies. One of them is the Three Gorges Dam, which represents the largest gravity dam, as well as the largest hydroelectric complex in the world. The technology of the project is extremely complex, and together with the comprehensive benefits to the community, makes the project more challenging than any other hydro project in the world.</p>

Modeling and Data Mining Analysis for Long-Term Temperature-Stress-Strain Monitoring Data of a Concrete Gravity Dam

The safety condition of concrete gravity dams is influenced by multiple factors, and assessing their safety solely based on a single factor is difficult to comprehensively evaluate. Therefore, this paper proposes a comprehensive modeling and analysis approach to assess dam safety by considering long-term temperature, stress, and strain monitoring data of actual concrete gravity dams. Firstly, the K-means clustering algorithm is utilized to classify the data. Then, the study area of the dam is meshed and three indicator evaluation values for all the elements are calculated. The other elements’ evaluation values can be obtained by the Inverse Distance Weighting (IDW) method. Finally, the analytic hierarchy process extended by the D numbers preference relation (D-AHP) method is applied to compute the weights of temperature, stress, and strain and evaluate the dam’s safety comprehensively. The effectiveness of this method is validated through application to specific engineering cases. The results demonstrate that compared to assessing methods considering only single factors, the comprehensive evaluation method proposed in this paper can more comprehensively and accurately reflect the actual safety condition of concrete gravity dams, providing important references for engineering decision-making.

Leakage detection applied to the Da Hedong Reservoir dam (China) based on the flow-field fitting method

Detecting leakage in concrete gravity dams presents a formidable challenge. The flow-field fitting (FFF) method is used to identify leaks in China’s Da Hedong Reservoir dam. We develop vertical- and horizontal-gradient approaches based on the transmitted signal electrical field. A plastic frame is developed to allow the probe to measure horizontal gradients. We determine the exact location of leaks at the reservoir’s bottom and upstream face, respectively, assuming that current leakages are located in hydraulic leakage zones. Numerical experiments and water pressure tests reveal that the conductive silt layer beneath the reservoir can lower the response of the potential values at the leakage inlet, and the effect of the silt layer should be considered and not ignored when interpreting measured data. In addition, with regard to the principle of superposition, the contribution associated with metal pipes in the dam body can be roughly determined by subtracting it from the original potential field data, thereby aiding in locating leaks around the metal pipes. In addition, the FFF measurements from the reservoir’s bottom also confirm the position of existing faults in the substratum at the reservoir site. Last, the results of the FFF method are tested against supporting evidence, such as ground penetrating radar and water pressure tests. In conclusion, these independent data confirm the effectiveness of the FFF method for leakage localization in the concrete gravity dam.

Evolution mechanism of hydraulic fracture in concrete under dynamic loading

The influence of hydraulic loading within cracks on the evolution mechanism of concrete under dynamic loading was investigated in this paper. Several strain gauges were employed to stick along the crack tip during the experiments. The moving crack tip was captured using these gauges during fracture. In particular, during the stable cracking stage, consistent propagating crack-tip speeds were observed under varying water pressures. Initially, the measured speed measured 2.0 m/s, which later increased to 20.0 m/s. Based on hydraulic experiments, a relationship between the crack tip and the water front was established, allowing the derivation of pressure distribution within crack from experimental data collected under dynamic loading conditions. Furthermore, the fracture parameters, including initial toughness, critical toughness, and cohesive toughness, were calculated for concrete subjected to split loading. The cohesive toughness experienced a 13.9% reduction with the increasing hydraulic pressure to 0.4 MPa, highlighting the deterioration of cohesive fracture toughness due to water infiltration within the concrete crack. This study provides insights to improve the design of civil and hydraulic engineering structures, such as gravity dams.

Self aeration and energy dissipation on a steep stepped chute: how does physical modelling compare to prototype observations?

For the last five decades, a number of overflow stepped chutes were built because the staircase shape is conducive to reduced construction costs and increased rate of energy dissipation. The stepped chute operations are characterised by air‐water flows that are highly turbulent flows with a large rate of energy dissipation, in comparison to smooth chutes. Herein, physical measurements were performed in a large‐size 1 V: 0.80H stepped chute model, with a steep slope typical of modern concrete gravity dams. The results are compared to visual observations of prototype spillway operation under Froude similar conditions. The detailed two‐phase flow measurements were conducted to characterise finely the self‐aeration and air diffusion process downstream of the inception region of free‐surface aeration. The bubble count rate profiles scaled with the instantaneous void fraction variance, and the relationship was biased close to the stepped invert under the influence of large‐scale vortical structures. The rate of energy dissipation was carefully estimated based upon the two‐phase flow measurements and the results are compared to earlier results on similar steep invert slopes and prototype data estimates. At the downstream end of the stepped chute, the rate of energy dissipation ranged from 43 to 46%, i.e. more than twice that on a smooth-invert chute for a similar chute length and discharge range.Graphical abstractCharacteristics of self-aerated stepped chute flows for dc/h = 1.3—(I) Prototype flow at Hinze Dam (Re = 4.0 × 107); (II) Air-water flow properties in the large-size laboratory model (1:15) stepped spillway (Re = 6.1 × 105)

Space–time finite element method with domain reduction techniques for dynamic soil–structure interaction problems

AbstractDesign of earth structures, such as dams, tunnels, and embankments, against the vibrational loading caused by high‐speed trains, road traffic, underground explosions, and, more importantly, earthquake motion, demands solutions of the dynamic soil–structure Interaction (SSI) problem. This paper presents a velocity‐based space–time finite element procedure, v‐ST/finite element method (FEM), to solve dynamic SSI problems. The main goal of this study is to present the computation details of implementing viscous boundary conditions of Lysmer–Kuhlemeyer to truncate the unbounded soil domain. Furthermore, additional time‐dependent boundary conditions, in terms of the free‐field response, are included to facilitate energy flow from the far field to the computation domain at the vertical truncated boundaries. In the FEM, seismic input motion is applied to an effective nodal force vector, which can be obtained explicitly in the numerical simulations. Finally, the response of a concrete gravity dam resting on an elastic half‐space to the horizontal component of earthquake motion is computed and successfully compared with the results of semidiscrete FEM using the Newmark‐ method.

Damage effect of underwater explosion bubble on concrete gravity dam

The underwater explosion bubble accounts for half of the total explosive energy and has been found to induce serious structural damage to ship structures. However, the existing research has commonly ignored the damage effect of an underwater explosion bubble on a concrete gravity dam. The current study aims to narrow this gap through high-fidelity numerical simulations and scale model tests. A fully-coupled numerical model is established first and is validated by small-scale centrifugal model tests. The bubble dynamics of underwater explosions near the perpendicular dam structure have been explored. The main focus is then on the sequential damage effects of the underwater explosion shock wave, bubble pulse, bubble jet, and bubble collapse on a concrete gravity dam. It is found that the shock wave causes a first attack, inducing tensile cracks in the vulnerable part of the dam. Subsequently, the bubble pulse generates a secondary attack, facilitating the penetration of the tensile crack throughout the entire dam structure. Additionally, the bubble jet driving the high-speed fluid flow and the bubble collapse causing the uplifted free water surface, united with the upstream reservoir water with huge hydrostatic pressure, largely accelerate the fracture of the dam, then facilitate the fractured dam to fall downstream leaving a breach with certain widths in the dam’s upper part, and finally speed up the discharge of the upstream reservoir water through the breach. It also finds that the underwater explosion bubble can generate no new cracks in the gravity dam, even in the pre-damaged area as long as there are no obvious pre-cracks by the shock wave. That is, the shock wave is the key trigger for dam failure, without which the dam failure will not happen, while the bubble, united with the upstream reservoir water, accelerates the process of dam failure.

Effect of the close-in underwater explosion pressure distribution on the concrete gravity dam

Effect of the close-in underwater explosion pressure distribution on the concrete gravity dam

A Method for Evaluating Systematic Risk in Dams with Random Field Theory

The parameters of gravity dams and foundation materials objectively exhibit spatial variability due to environmental and load influences, which significantly affect the safety status of dam structures. Therefore, a safety risk analysis method for a gravity dam–foundation system based on random field theory is proposed in this paper. Spatial variabilities in materials are particularly considered by using the finite element method. Then, composite response surface equations for the performance function (PF) of strength and stability failure are established, and then, the system failure risk is obtained using the Monte Carlo method. The proposed method solves the problem wherein the effect of spatial variability on failure risk cannot be reflected accurately by the performance function of multi-element sliding paths, and the difficulties in solving the failure risk of the series–parallel system due to multiple failure paths and their complex correlations. The application of a gravity dam shows that the developed method overcomes the disadvantages of the traditional method, such as the homogenization of the spatially random characteristics of parameters and the overestimation of failure risk in the system due to large variance estimation.

Seismic analysis of gravity dam-foundation systems using stochastic spectral finite element method

Seismic analysis of dam-foundation systems is inherently complex due to uncertainties in material properties. This study investigates the effects of material randomness and heterogeneity on the seismic response of gravity dam-foundation systems using the stochastic spectral finite element method (SSFEM) based on the Karhunen Loève expansion and the polynomial chaos expansion. The Pine Plane dam is taken as an analysis example. First, the appropriate Karhunen Loève expansion modes and polynomial chaos order are determined for SSFEM by comparing them with the Monte-Carlo simulations. Subsequently, the seismic response of the dam is analyzed in the stochastic and deterministic models, respectively. Results indicate that material randomness and heterogeneity may reduce the seismic response of gravity dams, and the deterministic model may overestimate dynamic responses. Subsequently, the parametric analysis of the correlation length, which measures the spatial correlation between variables in different positions and indicates the size of heterogeneity material patches, is conducted. It is demonstrated that the correlation length would not significantly affect the mean responses, but a larger correlation length leads to greater dispersions in responses. Finally, the effects of randomness in the foundation are investigated. The heterogeneities in the foundation affect the response of the dam in the high-frequency range. Therefore, the uncertainty in material properties should be fully considered in a structural assessment and risk analysis.

Empowering Farmers to Enhance Water Use Efficiency: Innovative Practices in SSPC

The Sardar Sarovar project, featuring a gravity dam on the Narmada River in Gujarat, stands as one of the largest in terms of concrete volume globally. This study investigates the project's extensive canal network and its impact on agricultural productivity in the command area. Covering a vast expanse across multiple states, the project's irrigation allocation and water management strategies are examined. Special attention is given to addressing soil degradation issues, particularly salinity, and implementing farmer-centered interventions to enhance water use efficiency. Methodologies include land rejuvenation efforts, reclamation of salt-affected land, participatory irrigation management, and promoting improved agricultural practices. Results indicate successful mitigation of soil degradation and increased crop yields through strategic interventions like cotton-castor relay cropping which has demonstrated a 1.5-fold increase in income compared to sole cropping. Intercropping with isabgul/ajwain, and implementing deficit irrigation have resulted in a substantial 43% increase in overall yield, particularly in cumin cultivation. Farmers have also embraced innovative water-saving techniques, such as alternative furrow irrigation and strategic timing of irrigation during critical growth stages, resulting in water savings of 30-35%. However, challenges remain in achieving widespread adoption of participatory irrigation management practices. The study concludes with insights into the necessity of sustained social engineering efforts and community engagement for long-term water resource management and agricultural sustainability in the project area.

Influence of Monolith Length on Temperature Field of Concrete Gravity Dams

This paper examines the influence of monolith length on the temperature field of concrete gravity dams built using the block method. The developed 3D model is capable of conducting a thermal analysis of a 95.0 m high concrete gravity dam built using the block method, where each newly cast block represents a new analysis phase. The calculation accounts for the period of construction, the filling of the reservoir, and the service for a total duration of about 5 years. The thermal properties of the material, the influence of cement hydration heat, the temperature of the surrounding rock mass, the temperature of the fresh concrete mixture, and the corresponding boundary conditions defining a heat transfer were taken into account. The height and width of the blocks, as well as the sequence of concreting, were considered invariable, while the length of the blocks (dimension in the direction of the dam’s axis equal to the monolith length) varied, with values of 10.0, 12.5, 15.0, and 20.0 m. The obtained calculation results for the control nodes showed that the maximum reduction in the monolith length (from 20.0 m to 10.0 m) caused a decrease in the maximum temperature values of the concrete (from 1.6 to 3.4 °C, depending on the control node). Also, the results showed that, by reducing the length of the monolith, there was a delay in the moment at which the maximum temperature values of the concrete appeared in the selected control node. The delay in reaching the maximum, in relation to the 10.0 m long monolith, was from 7 days (for points on the crest dam) to 49 days (for points in the central zone of the monolith) for the other considered monolith lengths. The above indicates the importance of concrete temperature control for longer monoliths, especially during construction in extreme air temperatures. The main contribution of the conducted analysis is the development of insight into temperature field changes depending on monolith length, which can help engineers during the design and construction of new, as well as the maintenance of existing, dams.

A Numerical Investigation of Seismic Load Analysis for a Concrete Gravity Dam Utilizing Abaqus Software

Current research efforts focus on ensuring the safety of extant dams against seismic loads and designing earthquake-resistant new dams. Dependable analytical procedures are essential for a safe design that can withstand the forces induced by earthquakes. In this research, the Pine Flat Dam in California, United States, was subjected to modal, static, and dynamic analyses utilizing the Abaqus software to evaluate the impact of hydrostatic forces and dynamic stresses on the dam, taking into account flexible foundations. Using the vertical component and the horizontal component Taft Lincoln School Tunnel earthquake data, dynamic linear and nonlinear performance for concrete gravity dam were conducted. The results obtained from the nonlinear analysis exhibited a noteworthy decrease in the highest primary stress at the heel of the concrete dam, dropping from 3.17 MPa to 1.31 MPa. Conversely, no variation was observed in the minimum principal stress. In addition, the dam's maximum principal stress has shifted from its base to its neck. The findings from these analyses can contribute to enhancing new dam designs and evaluating seismic safety for existing dams. This study highlights the importance of accurate analytical procedures in ensuring dam safety and provides significant observations regarding the behavior of concrete dams during earthquake loading.