Research on Influence of the Bank Slope on the Acceleration Distribution of the Central Points of Concrete-Faced Rockfill Dam

2012 ◽  
Vol 568 ◽  
pp. 242-247
Author(s):  
Hui Zhou ◽  
Ping Hu ◽  
Ren Cheng Xiao
Keyword(s):  
Seismic Intensity ◽  
River Valley ◽  
Response Analysis ◽  
Dynamical Response ◽  
Maximum Acceleration ◽  
Systematic Analysis ◽  
Horizontal Acceleration ◽  
Bank Slope ◽  
Rockfill Dam ◽  
High Dams

3-D dynamical response analysis of concrete-faced rockfill dam is presented. Using equivalent-linear model, based on different dam heights and different shapes of river valley, the responses of dam subjected to different seismic intensity inputs have been studied. Especially the systematic analysis about the influence of the bank slope on the distribution of the acceleration at the central points the bank slope is conducted. The results show that, the distribution of the horizontal acceleration along the dam heights at the central points on the central section of concrete-faced rockfill dam performs that the acceleration magnification which increases remarkably over 0.8H is a little smaller during 0~0.8H. For high concrete-faced rockfill dam, with the base acceleration excitations unchanged and the bank slope becoming gentle, the maximum acceleration on the top of the dam reduces. Under various seismic intensities, for non-high dams in the broad river valley the slope has almost no impact on the magnification of the horizontal acceleration.

Research on Influence of Valley Width on the Acceleration Distribution of the Central Points of Concrete-Faced Rockfill Dam

2012 ◽  
Vol 212-213 ◽  
pp. 853-858
Author(s):  
Hui Zhou ◽  
Ping Hu
Keyword(s):  
Seismic Intensity ◽  
River Valley ◽  
Response Analysis ◽  
Dynamical Response ◽  
Systematic Analysis ◽  
Horizontal Acceleration ◽  
Bank Slope ◽  
Valley Slope ◽  
Rockfill Dam ◽  
Equivalent Linear Model

3-D dynamical response analysis of concrete-faced rockfill dam is presented. Using equivalent-linear model, based on different dam heights and different shapes of river valley, the responses of dam subjected to different seismic intensity inputs have been studied. Especially the systematic analysis about the influence of the valley width on the distribution of the acceleration at the central points the bank slope is conducted. The results show that, the distribution of the horizontal acceleration along the dam heights at the central points on the central section of concrete-faced rockfill dam performs that the acceleration magnification which increases remarkably over 0.8H is a little smaller during 0~0.8H. For high concrete-faced rockfill dam, with the base acceleration excitations unchanged and the bank slope becoming steep (a gradient of 0.4), the valley width has a great impact on the magnification of the horizontal acceleration. The narrower the river valley is, the bigger the acceleration magnification is. With the slowing of the valley slope, the distribution of the acceleration magnification remains unchanged but the maximum reduces a little.

Empirical Formula for Calculating Maximum Acceleration of Concrete-Faced Rockfill Dam

2011 ◽  
Vol 243-249 ◽  
pp. 4557-4563
Author(s):  
Hui Zhou ◽  
Jun Jie Li ◽  
Fei Kang
Keyword(s):  
Empirical Equation ◽  
Amplification Factor ◽  
Seismic Intensity ◽  
River Valley ◽  
Seismic Stability ◽  
Maximum Acceleration ◽  
Rockfill Dam ◽  
Seismic Amplification ◽  
Different Shapes ◽  
Equivalent Linear Model

On the condition of different dam heights and different shapes of river valley, 3-D dynamical responses of concrete-faced rockfill dams subjected to different seismic intensity input are analyzed based on equivalent-linear model in this paper. The results show that on the condition of the same dam height and the base acceleration excitations unchanged, the position of the maximum acceleration on the axis of the top moves from the middle to the riversides symmetrically with the increase of the river valley width. For the narrow river valley, the position of the maximum acceleration which occurs near the riversides to the wide valley is on the middle of the axis at the top. The result negates the application of 2-D dynamical computation for wide valleys, and shows that for the seismic response of high concrete-faced rockfill dams, the seismic amplification factor along the axis should be given, except for that along the dam heights. Statistical analysis is also made to the seismic coefficient, and an empirical equation for calculating the maximum acceleration of the dam is provided, which provide an reference for the seismic stability analysis of rockfill dams using pseudo-static method.

Study on the Mechanism of the Peculiar Behaviors of the Aratozawa Dam During the 2008 Earthquake

2018 ◽  
Vol 13 (1) ◽  
pp. 205-215
Author(s):  
Nario Yasuda ◽  
Norihisa Matsumoto ◽  
Zengyan Cao ◽  
◽  
Keyword(s):  
Strong Earthquake ◽  
Dynamic Properties ◽  
Residual Deformation ◽  
Response Analysis ◽  
Maximum Acceleration ◽  
Amplification Ratio ◽  
Rockfill Dam ◽  
Acceleration Amplification ◽  
Sliding Stability ◽  
Earthquake Response Analysis

During the Iwate-Miyagi Nairiku Earthquake (M7.2) of June 14, 2008, seismic motions with a maximum acceleration of 1,024 cm/s2 in the stream direction were recorded at the foundation bedrock of Aratozawa Dam, a rockfill dam located approximately 16 km from the epicenter. However, the maximum response acceleration in the same direction near the center of the dam crest was 525 cm/s2, and the acceleration amplification ratio of the dam body was far lower than that normally considered for a rockfill dam. Furthermore, it was measured that the crest settled down 19.8 cm after the earthquake. In this study, the dynamic properties of the embankment materials were identified using reproduction analysis of past earthquakes, and the recorded behaviors of the dam body during the mentioned strong earthquake were simulated. The generating mechanism of the peculiar earthquake behavior was investigated based on the results of the earthquake response analysis. Furthermore, in order to understand the deformation mechanism, sliding stability analysis and cumulative damage analysis were performed. According to the results, the residual deformation of the dam body after the strong earthquake is inferred to be caused by the shaking settlement of the embankment materials.

Sensitivity Analysis for Dynamical Response of Reactor Coolant System Based on OPTIMUS

2020 ◽  
Author(s):  
Yuan Yanli ◽  
Ye Xianhui ◽  
Li Lijuan ◽  
Yuan Feng
Keyword(s):  
Sensitivity Analysis ◽  
Steam Generator ◽  
Nuclear Power ◽  
Reactor System ◽  
Response Analysis ◽  
Dynamical Response ◽  
Calculation Error ◽  
Reactor Coolant ◽  
Input Parameters ◽  
Coolant System

Abstract The sensitivity analysis of the dynamical response of reactor coolant system to the input parameters is an important precondition for the design optimization. In this paper, the sensitivity of the dynamical loads at the nozzles of the equipment under seismic conditions is analyzed with an integrated platform called OPTIMUS, taking the stiffness of the dampers in the steam generator and the main pump as the input variables. The key parameters of the reactor system are usually different from the design value due to the calculation error, random and other uncontrollable errors in the manufacturing process and installation process. In a nuclear power project, the measured stiffness values of the dampers on the steam generator and the main pump in the manufacturer are deviated from the requirements in the equipment specification, and it is necessary to evaluate the influence of the deviation on the dynamical response analysis of the reactor system. According to the traditional method, it is necessary to establish the models of the reactor coolant system for nonlinear analysis according to the different stiffness of the dampers, and then the calculation results are compared by EXCEL. In this paper, the sensitivity analysis of output parameters which are the loads at the nozzles of the equipment to the input parameters which are the stiffness of the dampers on the steam generator and pump is realized by OPTIMUS, which is a kind of integration platform. Not only can ANSYS simulation calculations be carried out automatically on the OPTIMUS, but also the output data can be processed rapidly automatically, and the influence of manufacturing deviation of the stiffness of the dampers on the dynamical response of the reactor coolant system can be analyzed quantitatively in the above-mentioned problems, and the data support is provided for the determination of the design variables for subsequent optimization analysis.

Numerical Analysis of Keddara Dam under Seismic Motion

2018 ◽  
Vol 40 ◽  
pp. 47-62
Author(s):  
Samia Louadj ◽  
Ramdane Bahar ◽  
Nasser Laouami
Keyword(s):  
Numerical Analysis ◽  
Seismic Event ◽  
Dominant Frequency ◽  
Lagrangian Analysis ◽  
Maximum Acceleration ◽  
Low Coherence ◽  
Seismic Motion ◽  
Rockfill Dam ◽  
Seismic Amplification ◽  
Boumerdes Earthquake

The Boumerdes earthquake of May 21, 2003 in Algeria, which widely felt within a radius of ~ 400 km, caused damage in five provinces. Numerous structures have been devastated, others suffered of damages. Keddara rockfill dam which is situated approximately at 20 km from the epicentre was strongly shaken during this seismic event and can undergo significant deformations. In this study, numerical analysis of Keddara rockfill dam under Boumerdes earthquake is performed. It is mainly focus on the seismic amplification at different level of the dam under the main shock with dominant frequency close to the natural frequency of the dam. The low coherence between the input and the structural output indicates the need of nonlinear analysis of the dam under the spatial variation in excitation. Furthermore, the effect of plasticity on the seismic response is investigated by using maximum acceleration which is one of the most important properties selected. The analysis of the dam under stochastic non-uniform excitation is conducted using a 2-D finite difference modeling by using the software Fast Lagrangian Analysis of Continua (FLAC). The final results obtained after successive analyses on the dam configuration incorporating the nonlinear soil properties are presented.

DEVELOPMENT OF PORTABLE VIBRATION EXPERIMENT DEVICE TO SUPPORT INTUITIVE UNDERSTANDING

2017 ◽  
Vol 4 (1) ◽  
Author(s):  
Osamu Tsujihara ◽  
Yuichi Nakatani ◽  
Terumasa Okamoto ◽  
Takeshi Yamamura
Keyword(s):  
Fourier Spectrum ◽  
Seismic Intensity ◽  
Shaking Table ◽  
Wave Form ◽  
Motivation To Learn ◽  
Structure Model ◽  
Maximum Acceleration ◽  
Vibration Experiment ◽  
Fourier Spectra ◽  
Experiment Device

The scale of vibration is expressed by such measures as the acceleration and seismic intensity. However, it is not realistic for those who have no experiential sense for the scale of vibration. The intuitive feel of vibration helps to foster motivation to learn such the subjects as the earthquake disaster prevention, vibration and earthquake resistance in the department of civil engineering and the architecture. This paper introduces the portable shaking experiment device which is developed as a teaching material to support the intuitive understanding of the scale of vibration such as acceleration and seismic intensity as well as Fourier spectrum. The data of vibration recorded by the accelerometers installed at the shaking table and structure model are processed immediately and the wave form, maximum acceleration, seismic intensity and Fourier spectra are shown in real time. The effectiveness of the proposed experiment device is discussed by the questionnaire survey.

3D Dynamic Analysis of a 270m Concrete Faced Rockfill Dam

2011 ◽  
Vol 287-290 ◽  
pp. 3131-3134
Author(s):  
Da Wei Sun ◽  
Kang Ping Wang ◽  
Guo Dong Zhang ◽  
Hui Qin Yao
Keyword(s):  
Permanent Deformation ◽  
Linearization Method ◽  
Equivalent Linearization ◽  
Element Mesh ◽  
Maximum Acceleration ◽  
Rockfill Dam ◽  
Calculation Results ◽  
Equivalent Linearization Method ◽  
Strain Model ◽  
Maximum Horizontal Acceleration

3D finite element mesh for a 270m high CFRD was generated with advanced grid discretion technology. Adopting EI-Centro seismic wave with maximum horizontal acceleration 0.277g, dynamic response of this 270m high concrete faced rockfill dam was obtained by equivalent linearization method. Using residual strain model, the permanent deformation of the dam was obtained. Calculation results showed that the maximum acceleration and displacement of dam body, dynamic stress of face slab and deformation of joints are all within normal range. Therefore, the safety of dam would be guaranteed when it is subjected to 7 degree earthquake.

Analysis on Seismic Response Characteristics of a Face Rockfill Dam across an Extra Wide River Valley

2011 ◽  
Vol 374-377 ◽  
pp. 2283-2286
Author(s):  
Jia Jun Pan ◽  
Ling Jiang ◽  
Yun Chen
Keyword(s):  
Seismic Response ◽  
Dynamic Stress ◽  
River Valley ◽  
Response Characteristics ◽  
Seismic Engineering ◽  
Rockfill Dam ◽  
Depth Ratio ◽  
Richter Scale ◽  
Engineering Measures ◽  
Earthquake Action

No relevant high earth face rockfill dams built across a river valley with a width-to-depth ratio of more than 8.0 is reported both at home and abroad. In this paper, non-linear finite elements method is adopted to analyze the seismic response of a 139m high CFRD proposed across a river valley with a width-to-depth ratio of 9.5, and dynamic response conditions such as dam’s absolute acceleration, dynamic displacement and dynamic stress etc., are highlighted Analysis results show that under existing design conditions, due to great river valley’s width-to-depth ratio, dam’s seismic response under an earthquake action of 8 Richter Scale is not intense, but an evident whipping effect occurs at the crest, it is necessary to take corresponding anti-seismic engineering measures.

Determination of the Bearing Quality by Means of Vibroacoustic Response

2015 ◽  
Author(s):  
Stanislav Ziaran ◽  
Milos Musil ◽  
Ondrej Chlebo
Keyword(s):  
Quality Evaluation ◽  
Dynamical Response ◽  
Frequency Interval ◽  
Maximum Acceleration ◽  
Operational Conditions ◽  
Means Of Measurement ◽  
Damage Type ◽  
The Given

A signal of mechanical and acoustical vibration generated during a bearing’s quality testing contains variety of useful information about their operational conditions. At defined testing speeds, the bearings generate a periodical and a non-periodical vibroacoustic signal of different intensities, which are dependent on the quality of bearings and/or their damage type. A dynamical response of the tested bearings recorded in time characterizes also the nature of the unwanted noise of bearings. Therefore the dynamical response of the maximum acceleration recorded in time is one of the major criteria of bearing quality evaluation in terms of noisiness. The second criterion is a determination of statistically significant frequency interval for the equivalent acceleration value expressed in decibels. Consequently, from the effective acceleration value, the bearing quality can be determined in terms of its vibration severity, as well as its noise level. This objective methodology substitutes the evaluation bearing quality by means of measurement of the vibration acceleration on the given test device and simultaneously evaluation of the noise quality and its intensity auditorily. Verifying the proposed methodology 100 % conformity was achieved between the methodology currently used and the new methodology, which eliminates the subjective quality evaluation of bearings auditorily.

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