High Core Rockfill Dam Research Articles

3-D Seismic Response Analysis Methods of High Core Rockfill Dams

Based on dynamic triaxial test data of dam materials, a dynamic constitutive model is suggested. Combining with construction of a high core rock-fill dam, several key issues, such as dam seismic response, seismic slope stability, dam permanent deformation, filter layer anti-liquefaction, and dynamic strength of the core wall are analyzed using 3-D dynamic effective stress analysis method. Some useful conclusions and regularity are obtained in aspects of seismic response and anti-seismic properties. The analysis method and conclusions could be referred to the analogous engineering.

Comprehensive Evaluation of the Coupling Construction Progress and Quality of High Core Rockfill Dam

Construction progress and quality are two important objectives in the construction of high core rockfill dam. It is of great significance to evaluate their control effect comprehensively. In this paper, the progress and quality of high core rockfill dam construction management are the study objectives. in order to achieve the real-time control of coupling them, the comprehensive evaluation method for the quantitative analysis of their complex relationship is proposed. Based on the comprehensive analysis of the mechanisms of the influence related factors in the construction process, the comprehensive evaluation index system of the high core rockfill dam coupling construction progress and quality is designed ; the comprehensive evaluation index data acquisition process is analyzed; the comprehensive evaluation method for the high core rockfill dam filling unit is put forward. finally, a comprehensive evaluation of high core rockfill dam filling unit model based on TOPSIS is established. Engineering examples show that this method plays a guiding role in real-time control of coupling high core rockfill dam construction progress and quality.

Research on Construction Schedule Real-Time Control of High Core Rock-Fill Dam Based on Digital Monitoring

The real-time control of the construction schedule for the high core rock-fill dam is researched, and the construction schedule forecasting and analysis method for the high core rock-fill dam is proposed based on the real-time monitoring and simulation. According to the basic principles of schedule control, the control process of construction schedule for the high core rock-fill dam is established, and the implementation method of the dynamic adjustment and control for construction schedule of the high core rock-fill dam is put forward by comparing the current construction schedule with the plan and combining measures such as earthwork dynamic balance optimization and dynamic adjustment and optimization of construction method. The achievement has been used in a hydropower project in southwest China, which provides strong technical support for the high standard construction of the project.

Seismic Design and Safety Evaluation Analysis of Reinforced Slope with Geogrid in 200m High Core Rock-Fill Dams

The reinforcement technique with strengthening geogrid has been widely used in modern seismic design of 200m high rock-fill dams. However, how to evaluate accurately the effects of reinforcement in seismic design and safety evaluation has become a key problem. As compared with the minimum safety factors which are conventionally employed as the evaluation criteria, the earthquake-induced deformation can better reflect the characteristics of rock-fill materials, input motion and the performance of reinforced dams for the earthquake loading. In the improved Newmark sliding method, the effects of reinforcement in enhancing the stability of slope in high rock-fill dams and restricting the permanent deformation of dams are investigated. Firstly, the limit tensile intensity and limit coordinating strain of reinforcement is determined based on the stress-strain relationship of reinforcement-composite and rock-fill materials. Secondly, the location of critical failure face is determined via a combination of ant colony algorithm and Holland method. The yielding acceleration of potential sliding bodies, which considers the limited stress of reinforcement layers and time-history vertical acceleration, is obtained. Finally, the transient movements are accumulated for all the overloadings. It is guaranteed that the reinforcement can reduce the permanent deformation up to 80% and improve the seismic design and safety evaluation of high rock-fill dams subjected to strong ground motion effectively.

Study on Effects of Softrock-Contained Rockfill for Stress and Deformation of High Core Rockfill Dam

Taking the rockfill dam of Nuozhadu as a example. Through the experiment on excavated softrock-contained rochfill with different deterioration degree, obtained related computational parameters. Useing Pseudo Load Method, compute and analyse effects of softrock-contained rockfill for stress and deformation of high core rockfill dam. Conclude that weathered soft rocks cause mechanical properties deterioration of rockfill, but only increase stress level of corewall upstream face, and destruction zone don't occur. It is feasible that softrock-contained rockfill are utilized in the secondary rockfill zone of high core rockfill dam.

Real-time compaction quality monitoring of high core rockfill dam

The conventional quality control method of core rockfill dam construction exhibit difficulty controlling compaction parameters accurately or ensuring construction quality. This is because it is easily influenced by human behavior or lack of adequate management. We therefore establish the timely monitoring indexes and control criteria of compaction processes by considering the characteristics and quality requirements of high core rockfill dam construction. Based on the established indexes and criteria, integrating GPS, GPRS and PDA technologies, a real-time compaction quality monitoring method is proposed. The relevant key techniques are proposed as well, including automatic collection of information and a graphic algorithm for rolling-process visualization. By the proposed method and techniques, a real-time monitoring system is provided to realize the precise automatic online entire-process monitoring of compaction parameters, including compaction pass, rolling trajectory, running speed of roller, vibration status and rolled pavement thickness. The application of the Nuozhadu project shows that the proposed system can control compaction parameters effectively and ensure better construction quality. Therefore, it might become a new way towards construction quality control of high core rockfill dam.

Seismic Response Analysis Method of High Core Rockfill Dam

A dynamic constitutive model is suggested based on dynamic triaxial test data of dam materials. Combining with construction of a high core rock-fill dam, several key issues, such as dam seismic response, dam permanent deformation, filter layer anti-liquefaction, dynamic strength of the core wall are analyzed by using 3-D dynamic effective stress analysis method. And some useful conclusions and regularity are obtained in the aspects of seismic response and anti-seismic properties. The analysis method and conclusions could be referred to the analogous engineering.

Numerical Simulation Study on Slaking Deformation Properties of High Earth Core Dam

The initial soaking of coarse-grained soil will trigger significant slaking deformation of this material. In order to study the slaking deformation of a certain dam during impounding process and its impacts on the dam body, we have adopted the slaking constitutive model by singe-line method and relevant test parameters from Changjiang River Scientific Research Institute, and conducted numerical simulation on the whole process from rock filling to impounding and slaking process of high earth core rockfill dam. The result has shown that, after considering slaking deformation of upstream shell materials, the upstream settlement is generally larger than downstream settlement on the same horizontal line, and the settlement of downstream shell materials generally stays unchanged after considering slaking deformation; at the early impounding period, the settlement of dam body is increasing, and the horizontal displacement of upstream side shell materials is pointing towards upstream. These findings can adequately explain the slaking deformation of the dam caused by impoundment, testify the new slaking constitutive model by single-line method and relevant test parameters, and provide reasonable basis for engineering design.

A modified approach for determination of nonlinear properties in seismic response analyses for 200 m high core rock-fill dams

Equivalent linear analyses are widely used for estimation of site response and safety status of rock-fill dams subjected to strong earthquakes. However, the average normalized curves incorporated in the equivalent-linear iterative process cannot precisely depict the variations of dynamic parameters with shearing strain for one type of soil material under a wide range of confining pressures. Thus, a modified approach for the determination of nonlinear properties for soil elements confined under a broad range of effective pressures in site response analyses for high rock-fill dams (>200 m) is proposed. In this approach, the normalized confining-pressure-interpolating curves (CPI curves) of each soil element under different effective stress are obtained by linearly interpolating or extrapolating by its in situ stress. By comparing the results obtained by equivalent linear analyses incorporating the average curves and the CPI curves, respectively, the impact of utilizing the recommended curves when determining nonlinear soil properties on site response analyses of high rock-fill dams (>200 m) is discussed. It is shown that the refinement in the determination of nonlinear properties during site response can be utilized in the near future by incorporating the results of this study in practice.

Rockfill Dams: Nantahala Sloping Core Dam

The design of a 250-foot high sloping core rockfill dam, part of a hydroelectric project, was determined to facilitate construction with materials readily available at the site. The paper describes the site and discusses construction procedures and performance.

Rockfill Dams: The Derbendi Khan Dam

Described in this paper are the problems pertaining to the design of a 450-foot high central core rockfill dam. Foundation excavation and preparations for diversion are now under way. The Derbendi Khan project consists of the rockfill storage dam, chute spillway, outlet works, and provisions for a future powerhouse. Diversion of the river was provided for by two tunnels that will serve the permanent outlet works and powerhouse after construction. A thorough field exploration and materials testing program provided a sound basis for the selection and design of the dam. Major problems were anticipated and are being provided for as a result.

Rockfill Dams: Nantahala Sloping Core Dam

The design of a 250-foot high sloping core rockfill dam, part of a hydroelectric project, was determined to facilitate construction with materials readily available at the site. The paper describes the site and discusses construction procedures and performance.