Roller Compacted Concrete Dam Research Articles

Extended IFC-based information exchange for construction management of roller-compacted concrete dam

Building Information Modeling (BIM) plays a pivotal role in the construction management of dam engineering projects, which face challenges in data interoperability due to the absence of standardized data formats. While Industry Foundation Classes (IFC) offer a standardized digital representation of the built environment, it lacks the capability to accurately model the semantics of roller-compacted concrete dams. Therefore, this paper presents an extended IFC-based information exchange for the construction management of roller-compacted concrete dams, incorporating the development and validation of a prototype through a case study. The results indicate a significant enhancement in standardized information exchange for construction management compared to traditional practices. The approach facilitates BIM-assisted information exchange automation among stakeholders involved in roller-compacted concrete dam construction projects. The findings of this study provide valuable insights into dam construction management system prototyping and cross-platform collaboration.

The effect of the gravity on the earthquake performance of roller compacted concrete dams

Roller compacted concrete (RCC) is a dry concrete mixture often utilized in the construction of large dams. The interlayer of the RCC dam, which is the weakest plane of the structure, can easily fail under hydraulic shear load, geological impact, earthquake force and environmental impact. In this study linear and performance analyzes were carried out for eight different scenarios for foundation effect, gravity effect and empty and full reservoir situations. In analyses, the earthquake response and performance of the Akçakoca RCC Dam, taking into account the interaction between the dam and the water. The reservoir water behavior is simulated using the Eulerian-Lagrangian coupled (CEL) approach with finite elements modeling. Linear analyses reveal that hydrodynamic pressure leads to increased displacements and principal stresses. The earthquake performance evaluation of the Akçakoca RCC dam indicates that critical concrete damages are expected based on linear time-history analyses conducted for both empty and full reservoir scenarios. Besides, according to this study, gravity effect clearly increases the earthquake performance of the dam.

Assessment of engineering geology and grouting applications in Yalnızardıç Dam Site (Antalya, Türkiye)

The Yalnızardıç roller compacted concrete (RCC) dam, constructed in 2015, is located in the Mediterranean region of Turkey, intended for electric power production. It is approximately 303 m long and 92 m in height. In this paper, it is aimed to determine the performance of the grouting method, conducted to control the water seepage and improve the foundation of the Yalnızardıç dam. The engineering properties of the site were introduced by geological mapping, drilling, and laboratory tests. The seepage of the foundation was determined by the in-situ Lugeon test method, also referred to as a water pressure test, which is estimate the mean hydraulic conductivity of rock mass. As a result of the tests, high-permeable and permeable zones were determined in the dam axis area. To make a barrier layer for these permeable zones, grout curtains were built in the left abutment, thalweg and right abutment with two lines of grouting holes which is proposed according to the Lugeon test and rock quality designation (RQD) results. Consolidation grouts were built to increase the density of the soil which makes the strength of the dam's foundation. After the groutings, check boreholes were drilled and water pressure tests were performed to control the seepage along the foundation and dam site. The results indicated that average Lugeon (LU) values reduced, and the values were within the recommended limit. The process shows considerable accuracy in evaluating grouting efficiency.

Deformation health diagnosis of RCC dams considering construction interfaces based on monitoring data and numerical simulation

The health diagnosis procedure applied to determine the deformation of a roller compacted concrete (RCC) dam is different from that of a conventional concrete dam. Hence, in this study, a deformation health diagnosis model was established for an RCC dam considering the construction interfaces by combining the hydrostatic component simulated using ABAQUS (2016) with the temperature and aging components calculated using a statistical method. The combined method can help monitor the structural health of RCC dam and determine the physical meaning and statistical law of the deformation of RCC dams. During the simulation process, the geometric characteristics of the construction interfaces were modeled using the interface equivalent expansion method. The material properties were modeled using multi-output least-squares support vector regression optimized with the Jaya algorithm. A case study demonstrated that the established deformation health diagnosis model has good fitting and prediction ability. The model and methods proposed in this study provide a new idea for the behavior analysis and numerical simulation of mass composite structures similar to RCC dams.

Assessing the stability of the reservoir rim in moraine deposits for a mega RCC dam

<abstract> <p>Diamer Basha Dam is an under-construction, 272-meter-high, roller compacted concrete (RCC) dam on the Indus River in Pakistan. Once constructed, it will be the world's highest RCC gravity dam with a 105-kilometer-long reservoir. Most of the reservoir lies in unstable moraine deposits with steep slopes. Events like saturation during reservoir filling, alternate wetting, drawdown during reservoir operation, or a seismic event could trigger a large mass movement of these slopes into the reservoir to disrupt the dam functionality. This work identified the 15 most vulnerable slide areas using digital slope maps, elevation maps, and satellite imagery. Deterministic slope stability analysis was carried out on the identified sections under various stages of reservoir operation for static and seismic loading, using pseudo-static and dynamic analysis approaches. Probabilistic analysis was then performed using Monte Carlo simulation. The findings showed that most moraine deposits would collapse under reservoir filling, rapid drawdown, or seismic activity. Following the assessments, landslide susceptibility maps were generated, and an assessment of potential impacts, including the generation of dynamic waves, reservoir blockage, increased sediment loads, and reduced reservoir storage capacity, was also performed.</p> </abstract>

Seepage Prediction Model for Roller-Compacted Concrete Dam Using Support Vector Regression and Hybrid Parameter Optimization

In this study, a seepage prediction model was established for roller-compacted concrete dams using support vector regression (SVR) with hybrid parameter optimization (HPO). The model includes data processing via HPO and machine learning through SVR. HPO benefits from the correlation extraction capability of grey relational analysis and the dimensionality reduction technique of principal component analysis. The proposed model was trained, validated, and tested using 22 years of monitoring data regarding the Shuidong Dam in China. We compared the performance of HPO with other popular methods, while the SVR method was compared with the traditional time-series prediction method of long short-term memory (LSTM). Our findings reveal that the HPO method proves valuable real-time dam safety monitoring during data processing. Meanwhile, the SVR method demonstrates superior robustness in predicting seepage flowrate post-dam reinforcement, compared with LSTM. Thus, the developed model effectively identifies the factors related to seepage and exhibits high accuracy in predicting fluctuation trends regarding the Shuidong Dam, achieving a determination coefficient R2 > 0.9. Further, the model can provide valuable guidance for dam safety monitoring, including diagnosing the efficacy of monitoring parameters or equipment, evaluating equipment monitoring frequency, identifying locations sensitive to dam seepage, and predicting seepage.

Normal statistical fracture analysis of Roller-compacted concrete on the basis of non-linear elastic fracture mechanics

Roller-compacted concrete (RCC) is widely used in dam structures; the fracture properties of RCC directly affect the cracking resistance of RCC dams. Solving the discrete problem of the RCC fracture properties and obtaining real material parameters is important for the healthy and stable operation of RCC structures. The tensile strength (ft) and fracture toughness (KIC) are two critical parameters that have a direct impact on the fracture properties of RCC structures. In this study, the relative ligament depth [(W − a0)/di] is associated with the fictitious crack growth length (Δafic). A normal statistical fracture model is developed to describe the dispersion of the RCC ft and KIC to obtain the real material parameters of RCC with different cement-to-aggregate (C/A) ratios. For an increase in the C/A ratio from 12 % to 17 %, the ft and KIC for each group of RCC structures are 4.05–6.35 MPa and 0.90–1.41 MPa·m1/2, respectively. Based on the results of the normal statistical analysis, fracture failure curves are constructed with 95 % reliability, revealing that the fracture behavior of RCC is quasi-brittle fracture. Additionally, a relationship between the peak load (Pmax) and the material parameters is proposed, this confirms the correctness of the proposed model. Finally, the relationship between indoor small-size specimens and actual engineering-scale RCC dams regarding fracture failure is discussed based on the fracture failure curve.

Determination of Safety Monitoring Indices for Roller-Compacted Concrete Dams Considering Seepage–Stress Coupling Effects

Analyzing the working conditions of a dam using safety monitoring indices (SMIs) is a relatively intuitive and effective method for dam safety evaluation. Therefore, a reasonable and accurate method for determining the SMIs of a dam is of vital importance for dam safety assessment. However, the current methods for determining the SMIs of dams, especially roller-compacted concrete (RCC) dams, have many shortcomings, such as ignoring the construction process of the dam, the coupling effect among multiple physical fields, etc. In this paper, a novel SMI determination method considering the seepage–stress coupling effects was proposed for RCC dams with the assistance of a constructed seepage and stress coupling model so as to address the deficiency of existing RCC dams in determining SMIs. The coupled mathematical model was developed in COMSOL Multiphysics to establish a finite element analysis model of an RCC gravity dam in Henan Province, China. Moreover, the seepage anisotropy of the RCC construction layers was also considered in the model. Finally, the seepage, stress, and deformation characteristics of the RCC dam were analyzed based on the model, and the seepage and deformation SMIs of the dam were determined and compared with traditional methods. The results show that seepage, stress, and displacement fields are distributed similarly for both coupled and uncoupled models. However, in contrast to the uncoupled model, the hydraulic head contour distribution is more dispersed in the coupled model. Additionally, the stress and displacement simulated by the coupled model increase at different rates, with a more pronounced stress concentration near the dam heel. Comparing the seepage and stress SMIs of RCC dam obtained from different methods, it was found that the indices of dam seepage discharge and crest displacement that are calculated by considering the seepage–stress coupling effect and anisotropic characteristics of RCC construction layers are 34.78% and 31.98% lower than results obtained by ignoring these two effects, respectively. Therefore, it is crucial to consider the seepage–stress coupling effect and the anisotropic characteristics of RCC when determining the SMIs for RCC dams.

Phase-field modeling of thermal cracking in hardening mass concrete

The manuscript is concerned with the phase-field modeling of thermal cracking in massive hardening concrete structures. Owing to the exothermic reactions, known as hydration, a considerable amount of heat is generated during the setting and hardening of concrete. Since concrete has relatively low thermal conductivity and fairly high heat capacity, sharp temperature gradients may occur between the interior and exterior parts of massive concrete structures. This uneven temperature distribution results in a non-uniform thermal expansion that, in turn, may lead to thermal cracking in conjunction with restraining external boundary conditions. Hence, it is of key importance to conduct the crack risk assessment of massive concrete structures at various stages of their construction and thereafter where real-size experiments are often unrealizable. To this end, we develop a multi-field computational approach to simulate thermal cracking in hardening concrete. In particular, we propose a novel chemo-thermo-mechanical model developed within the framework of the theory of reactive porous media coupled with a quasi-brittle phase-field regularized cohesive zone model to explicitly account for the initiation and propagation of thermal cracks. In the model, chemical, thermal, mechanical, and phase-field fracture problems are coupled through the constitutive equations. To our best knowledge, this is the first study where a quasi-brittle phase-field fracture model is used to model thermal cracking in hardening massive concrete through a novel incremental formulation. The potential of the proposed approach is demonstrated through the benchmark thermomechanical problems of a normal concrete member and a roller-compacted concrete dam. In the latter, original multi-field interface elements are devised between the lifts.

Crack Width – Seismic Intensity Relationships for Concrete Gravity Dams

ABSTRACT Seismic assessment of plain concrete structures like gravity dams is generally conducted based on cracking. The responses of two types of gravity dams, i.e. the conventional and roller compacted concrete (RCC), were investigated in this study using a discrete element tool coupled with special reservoir elements. Using incremental dynamic analysis, the relationship between the seismic intensity measures and crack widths on the U/S face of the monolith was obtained. The damage accumulation on conventional and RCC dams was different: The cumulative cracking on the upstream face of the monolith correlated well to a seismic intensity measure representing base shear.

Optimization of time and temperature of dam construction for thermal analysis of roller compacted concrete dam

Optimization of time and temperature of dam construction for thermal analysis of roller compacted concrete dam

Comprehensive Evaluation Method for the Safety State of RCC Dams Based on Interval Number Theory

Roller Compacted Concrete (RCC) dams are critical infrastructure, playing an important role in economic and social development. However, dam failure can cause great losses. To mitigate hazards, studies of methods to deal with the uncertainty involved in the comprehensive evaluation process of the safety state of RCC dams are hot issues. Interval number theory is applied to quantify the uncertainty in this study. A comprehensive evaluation indicator system is explored, an approach to allocating the indicator weight rationally is proposed, and a comprehensive evaluation model is established. Comprehensive evaluation standards are developed. An RCC dam in China is used to illustrate the applicability of this comprehensive evaluation method based on interval number theory. The results indicate that the method and models proposed are suitable for comprehensively evaluating the safety state of RCC dams and can be used as a new procedure to monitor the safety of an RCC dam.

Failure modes and dynamic responses of roller compacted concrete gravity dams subjected to underwater contact explosion based on the cohesive model

Considering the construction technology of roller compacted concrete (RCC) gravity dams, there are layers in dams inevitably, which may affect the blast responses of dams. This paper is aimed to investigate the effects of RCC layers on the failure modes and dynamic responses of RCC gravity dams bearing underwater contact explosion loading. Initially, the zero-thickness cohesive element model is presented to simulate the crack behavior of the RCC layers. An impact test of a concrete beam is selected to verify its reliability. The concrete damage plasticity model considering strain rate effects is utilized to simulate the various responses of concrete under blast load. The dam–reservoir–foundation interactions are described using the coupled Eulerian-Lagrangian method. The numerical methods are validated by a field blast test of a concrete structure. Subsequently, numerical models were established for gravity dam-reservoir-foundation systems, with and without considering RCC layers respectively. Based on validated algorithms, these models were utilized to explore the effects of RCC layers on the blast performance of the dam. Finally, the influence of the parameters of RCC layers on the nonlinear responses and failure modes of the dam is further investigated, including the maximum traction, the fracture energy, and the layer thickness. The results reveal that the layers significantly change the failure modes. The RCC layers are the weak link of the dam and they will lower the anti-explosion performance of the dam. Therefore, it is crucial to take the layers into account when conducting anti-explosion research, and RCC dams cannot be simply simplified as normal concrete dams. To guarantee the safety of the dam, it is important to ensure the layers with sufficient strength and fracture energy, as well as an appropriate thickness.

Type Selection between Arch Dam and Gravity Dam Based on Construction Simulation: A Case Study

The issue of dam type selection is a prevalent challenge in water resource allocation engineering. The site of the Y2 dam in China is suitable for building concrete arch dams and roller-compacted concrete (RCC) gravity dams. To determine which dam type is better in terms of construction progress, this paper proposes a multiattribute decision-making method based on construction simulation. First, the construction characteristics of concrete dams are analyzed, and the construction simulation systems for arch dams and gravity dams are developed based on construction simulation theory. Then, for each dam type, the initial construction schemes are used as the input of the simulation systems, and attribute values of construction progress are output. Secondly, a multiattribute decision-making method is used to select the typical scheme of each dam type from these initial schemes. Finally, the simulation results of the typical schemes for the arch dam and the RCC gravity dam are compared, to determine the optimal dam type for the Y2 dam. The results show that for the Y2 dam, the construction period of the arch dam is 34 months, and that of the RCC gravity dam is 28 months. From the perspective of construction progress, the Y2 dam type should select the RCC gravity dam. Compared with similar dams that have been built, it is concluded that the simulated progress result conforms to the current actual construction level, which also verifies the correctness of the calculation results and the reliability of the construction simulation.

In situ experimental study on mechanical properties of interlayer in roller compacted concrete (RCC) dam

Roller compacted concrete (RCC) is a kind of dry concrete widely used in the construction of large dams. As the weakest plane of the structure, the interlayer of the RCC dam is easy to deteriorate under the action of hydraulic shear load, geological action and environmental influence. Therefore, in this study, in combination with actual engineering, in-situ tests were carried out to study the shear properties of RCC interlayers under different cementing material treatments, different surface roughness, different exposure time and different stress. In addition, the failure modes were classified and analyzed, and the factors affecting the angle and depth of the plane undulation in the failed surface of RCC were summarized. The result shows that the shear strength of the RCC interlayer increases with the increase of normal stress. The increase of surface roughness results in better interlayer bonding and higher shear strength. After mortar treatment, the shear strength, cohesion and friction angle of the RCC layers are higher than those of the mortar treatment. The strength parameters of the RCC layer treated with cementing material are improved to a certain extent compared with that of the untreated layer. With the increase of layer exposure time, the interlayer strength parameters decreased gradually. The change of cementation between layers and the bite force of aggregate under different conditions is an important reason for the change of mechanical properties between layers of RCC. The experimental results are expected to enhance the understanding of the construction of hydraulic dams.

Seismic Response and Damage Characteristics of RCC Gravity Dams Considering Weak Layers Based on the Cohesive Model

Due to the construction technology of roller compacted concrete (RCC) gravity dams, there are many weak layers that have the potential to affect the seismic performance of dams. However, research on the seismic response and failure characteristics of RCC dams considering their layered characteristic is still lacking. In this paper, the zero-thickness cohesive element is presented to model the mechanical behavior of the RCC layers. An impacted concrete beam is selected to verify its effects on simulating crack propagation. Subsequently, the concrete damaged plasticity model is utilized to model concrete under seismic loading. The dynamic interaction in the gravity dam-reservoir-foundation system is considered by coupled acoustic-structural method, whose rationality is validated by seismic failure mode analysis of the Koyna dam under the 1967 Koyna earthquake. The validated algorithms are applied to investigate the influence of the weak layer at different elevations on the seismic response and the failure process of the Guandi RCC gravity dam. On this basis, the effects of well-bonded RCC layers set at intervals along the dam on the nonlinear response and failure modes under strong earthquakes are further investigated. The results reveal that the weak layer will influence the anti-seismic capacity of RCC gravity dams, and the damage characteristics of the dam are significantly changed. In addition, well-bonded RCC layers still affect the seismic response of RCC gravity dams. Increasing displacement response and energy dissipation can be observed. Meanwhile, RCC layers lead to more severe damage to the dam under the same seismic input.

A global sensitivity analysis method for safety influencing factors of RCC dams based on ISSA-ELM-Sobol

Structural material parameters will directly affect the stability and deformation of roller compacted concrete (RCC) dams. To analyze the influence degree of structural material parameters of RCC dams on the safety evaluation indexes, this study proposes a global sensitivity analysis method based on extreme learningmachines optimized by an improved sparrow search algorithm with Sobol method (ISSA-ELM-Sobol). First, the safety evaluation indexes of the RCC dam and their influencing factors are determined; second, a reasonable finite element model is established; third, the sample set is generated using the Latin hypercube sampling technique; fourth, the ISSA-ELM model is established to replace the finite element calculation; finally, based on the established ISSA-ELM model, the Sobol method is used for global sensitivity analysis. A case study for a typical RCC dam in Sichuan province of China showed that the material properties of the foundation and the cohesion of potential sliding surfaces have the most obvious influence on the safety of RCC dams; the ISSA proposed in this study can overcome the problem that sparrow search algorithm is easy to mature prematurely and fall into a local optimum. The ISSA-ELM model established in this study has significant advantages in solving nonlinear regression problems.

A thermal analysis of concrete structures performed by layers using boundary element formulation and dual reciprocity

This paper presents an application of the Boundary Element Method (BEM) in engineering to numerically analyse the thermal behaviour of structures executed by layers that present different temperatures at the time of overlapping and/or that present some type of internal heat generation. This type of phenomenon occurs, for example, in large concrete structures, where the structure has its temperature altered due to the hydration reaction of the cement during the concrete curing process. Using the developed formulation, it is possible to simulate the temperature field at all stages of the construction process and in different situations by changing the thermophysical parameters, taking into account the thermal influence of one layer on the others and on the structure as a whole. With the simulation results, it is also possible to define the deposition time between the layers of the structure, which is important information for cases in which the temperature variation may imply the appearance of thermal stresses, for example, or when the maximum temperature reached do not exceed a certain limit. The cases presented were directed to concrete structures, mainly roller-compacted concrete (RCC) dams, whose details of the construction process, as well as the heat diffusion process during the concrete curing process and the entire formulation of the boundary element, are presented below.

Hydraulic characteristics of flow over stepped and chute spillways (case study: Zirdan Dam)

AbstractStepped spillways are suitable and economical options for high-storage dams that require significant energy dissipation, structural adaptation to roller-compacted concrete dams, and spontaneous flow aeration. In this study, a numerical analysis of the hydraulic characteristics for the skimming flow regime of the stepped spillway of Zirdan Dam is carried out. A comparison between the flow characteristics for stepped and smooth spillways is provided. By preparing numerical models of the spillway using the k-ε RNG turbulence model and the multiphase mixture method, a hydraulic analysis of the flow was completed. To verify the performance of the numerical model, field data were collected and used for validation. The results show that the presence of steps along the spillway cause a significant reduction in the length of the boundary layer and faster aeration occurs. In a stepped spillway, the cavitation index is higher than the critical limit along the entire length of the spillway. Thus, the risk of cavitation and destruction is negligible. On the other hand, with a smooth spillway, the possibility of cavitation may occur. This negative effect (negative pressures) occurs 56 m from the crest of the spillway on the downstream side.

Innovative Structures of Very Lean Roller-Compacted Concrete Dams

Innovative Structures of Very Lean Roller-Compacted Concrete Dams