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To carry out the experimental study of flow-induced vibration for roller compacted concrete dam (RCCD), the improved hydroelastic model experiment (HEME) technology that satisfying both the hydraulic and structural dynamic similarities is presented, and an improved combinatorial method is proposed to effectively and accurately calculate the dynamic characteristics of RCCD model under natural excitation and complex environment. Due to the insufficient study on the simulation technique for the interfaces between adjacent concrete layers in RCCD, the conventional HEME technology which is frequently applied is not applicable to the RCCD dynamic analysis. Therefore, the hydroelastic simulation schemes for cold joints and ordinary interfaces in RCCD are firstly presented based on experimental and theoretical researches and numerical verification. Then, the integral RCCD model is established and its dynamic displacements under flood discharge excitation are tested. Furthermore, the proposed method that combines the advantages of natural excitation technique (NExT), singular entropy (SE) method, and eigensystem realization algorithm with data correlation (ERA/DC) method is applied to calculate the dynamic characteristics of RCCD model. The dynamic characteristics of the RCCD model calculated by the proposed theoretical method are very similar to those of the actual RCCD calculated by numerical simulation, which indicate the effectiveness and accuracy for the improved HEME technology and combinatorial method.
Yijia Li; Jianchao Hu; Bin Ma; Chao Liang. Development and verification of hydroelastic model experiment for the flow-induced vibration analysis of roller compacted concrete dam. Journal of Low Frequency Noise, Vibration and Active Control 2021, 1 .
AMA StyleYijia Li, Jianchao Hu, Bin Ma, Chao Liang. Development and verification of hydroelastic model experiment for the flow-induced vibration analysis of roller compacted concrete dam. Journal of Low Frequency Noise, Vibration and Active Control. 2021; ():1.
Chicago/Turabian StyleYijia Li; Jianchao Hu; Bin Ma; Chao Liang. 2021. "Development and verification of hydroelastic model experiment for the flow-induced vibration analysis of roller compacted concrete dam." Journal of Low Frequency Noise, Vibration and Active Control , no. : 1.
Due to the frequently occurred adverse vibration of hydraulic structures, vibration risk assessment is significant for the water energy efficiency of hydropower station and the safety of people and structures. Recently, the abnormal vibration of hydro-turbine-generator in a large hydropower station occurred and the main influencing factors of vibration are analyzed based on the prototype data and engineering experience. Different from the deterministic variable features in traditional support vector domain description (SVDD) algorithms, the feature of vibration amplitude is actually a random variable so that the different target objects will be obtained at different confidence levels. In order to assess the vibration range and excessive vibration probability, the original SVDD boundary at relatively low confidence level is firstly calculated. Then, the boundary extension operation with detailed theoretical deduction is performed and the extended boundary is further optimized inspired by path planning problem. The advantage of proposed approach is that it can improve the data fitting performance for single dimension (i.e. vibration amplitude) without leading to complex boundary which cannot be used for vibration risk assessment. By applying this approach to the practical vibration problem, the quantitative and slightly conservative assessment results are conveniently obtained, which indicate that this approach is reasonable and cost-effective.
Jinliang Zhang; Fengwei Yang; Chao Liang; Yuansheng Zhang; Yongchang Li. An SVDD-based post-processing approach for vibration risk assessment of the hydro-turbine-generator in a large hydropower station. Journal of Low Frequency Noise, Vibration and Active Control 2020, 1 .
AMA StyleJinliang Zhang, Fengwei Yang, Chao Liang, Yuansheng Zhang, Yongchang Li. An SVDD-based post-processing approach for vibration risk assessment of the hydro-turbine-generator in a large hydropower station. Journal of Low Frequency Noise, Vibration and Active Control. 2020; ():1.
Chicago/Turabian StyleJinliang Zhang; Fengwei Yang; Chao Liang; Yuansheng Zhang; Yongchang Li. 2020. "An SVDD-based post-processing approach for vibration risk assessment of the hydro-turbine-generator in a large hydropower station." Journal of Low Frequency Noise, Vibration and Active Control , no. : 1.
According to the results of a dynamic prototype test for the surface outlet radial gate on the Jinping high arch dam during the flood discharging process, a novel cause of vibration fundamentally different from the traditional causes of flow-induced radial gate vibration, is analyzed for the first time. Under the condition that the flood is discharged only from mid-level outlets, an accompanying vibration of the surface outlet gate is induced by the vibration of the closely spaced mid-level outlet gates. It is counterintuitive that the most intense vibration occurs when the surface outlet gate is closed and, on the contrary, the vibration is reduced when the gate is opened and subjected to flow excitation. In order to analyze and explain this accompanying vibration phenomenon, a theoretical model is developed based on the conventional theory of passive vibration absorbers. The difference between the proposed and conventional theoretical models is that more complex load and damping conditions are considered, and more attention was paid to the dynamic behavior of the accessory structure. Then, the cause and mechanism for the surface outlet gate vibration is clarified in detail, based on the proposed theoretical model. The comprehensive analysis and mutual verification of the prototype test, theoretical derivation and numerical simulation, indicate that the clarification and the proposed theoretical model is reasonable and accurate. The research reported in this paper will be beneficial for the design, operation and maintenance of the hydraulic gates installed on high arch dams.
Jijian Lian; Lin Chen; Bin Ma; Chao Liang. Analysis of the Cause and Mechanism of Hydraulic Gate Vibration during Flood Discharging from the Perspective of Structural Dynamics. Applied Sciences 2020, 10, 629 .
AMA StyleJijian Lian, Lin Chen, Bin Ma, Chao Liang. Analysis of the Cause and Mechanism of Hydraulic Gate Vibration during Flood Discharging from the Perspective of Structural Dynamics. Applied Sciences. 2020; 10 (2):629.
Chicago/Turabian StyleJijian Lian; Lin Chen; Bin Ma; Chao Liang. 2020. "Analysis of the Cause and Mechanism of Hydraulic Gate Vibration during Flood Discharging from the Perspective of Structural Dynamics." Applied Sciences 10, no. 2: 629.
Ground and environmental vibrations induced by high dam flood discharge from the Xiangjiaba hydropower station (XHS) has significant adverse effects on nearby building safety and the physical and mental health of surrounding residents. As an effective approach to simulate the flow-induced vibration of hydraulic structures, the hydro-elastic experiment approach has been extensively applied and researched by Chinese scholars, but the relevant systematic research is rarely reported in international journals. Firstly, the hydraulic and structural dynamic similarity conditions that should be satisfied by the hydro-elastic model are briefly reviewed and derived. A hydro-elastic model of the XHS was further constructed using self-developed high-density rubber, and the vibration isolation system (including open trenches and flexible connects) was applied to avoid the external disturbances of pump operation, vehicle vibration and other experiments in the laboratory. Based on the data of model and prototype dynamic tests, a back propagation (BP) neural network was established to map the acceleration of the physical model to the ground in the prototype. In order to reduce the ground vibration, experiments were carried out to meticulously evaluate the ground vibration intensity under more than 600 working conditions, and the optimal operation scheme under different discharge volumes is presented here in detail. According to the prototype test data in 2013, 2014, and 2015, ground vibrations were significantly reduced by applying the presented optimal operation principle which indicates that the presented hydro-elastic approach and the vibration attenuation operation scheme were effective and feasible.
Jijian Lian; Lin Chen; Chao Liang; Fang Liu. Presentation and Verification of an Optimal Operating Scheme Aiming at Reducing the Ground Vibration Induced by High Dam Flood Discharge. International Journal of Environmental Research and Public Health 2020, 17, 377 .
AMA StyleJijian Lian, Lin Chen, Chao Liang, Fang Liu. Presentation and Verification of an Optimal Operating Scheme Aiming at Reducing the Ground Vibration Induced by High Dam Flood Discharge. International Journal of Environmental Research and Public Health. 2020; 17 (1):377.
Chicago/Turabian StyleJijian Lian; Lin Chen; Chao Liang; Fang Liu. 2020. "Presentation and Verification of an Optimal Operating Scheme Aiming at Reducing the Ground Vibration Induced by High Dam Flood Discharge." International Journal of Environmental Research and Public Health 17, no. 1: 377.
This paper investigates the cascading dam-break flood propagation on the downstream sloping channel and reservoir using the shallow water equations (SWEs) and the Reynolds-average Navier-Stokes equations (RANS). The calculated surface profiles, stage hydrographs and maximum run-up heights for 24 sets of initial conditions are elaborately compared with the experimental measurements, which show the SWEs reproduce the wave oscillation evolution and the maximum run-up height inaccurately. The maximum run-up heights calculated by the SWEs are all smaller than those by the RANS and the measured results, the maximum errors are within −10% to −25%, which may predict delay of the downstream dam-break. However, the maximum errors calculated by the RANS are within ±10%. So the RANS predict more accurate results than the SWEs. Additionally, the generation of short waves must be below a certain upstream-to-downstream ‘depth ratio’, roughly the ‘depth ratio’ <2/3 in this study. If the ratio is too high, it is difficult to form a wavy push due to air entrainment and turbulence. The SWEs predict more accurate results for shallow initial depths than deep initial depths. Therefore, the advantage of the RANS can be more obvious for deep initial depths.
Shubing Dai; Yong He; Jijian Yang; Yulei Ma; Sheng Jin; Chao Liang. Numerical study of cascading dam-break characteristics using SWEs and RANS. Water Supply 2019, 20, 348 -360.
AMA StyleShubing Dai, Yong He, Jijian Yang, Yulei Ma, Sheng Jin, Chao Liang. Numerical study of cascading dam-break characteristics using SWEs and RANS. Water Supply. 2019; 20 (1):348-360.
Chicago/Turabian StyleShubing Dai; Yong He; Jijian Yang; Yulei Ma; Sheng Jin; Chao Liang. 2019. "Numerical study of cascading dam-break characteristics using SWEs and RANS." Water Supply 20, no. 1: 348-360.
During the flood discharge in large-scale hydraulic engineering projects, intense flow-induced vibrations may occur in hydraulic gates, gate piers, spillway guide walls, etc. Furthermore, the vibration mechanism is complicated. For the spillway guide wall, existing studies on the vibration mechanism usually focus on the vibrations caused by flow excitations, without considering the influence of dam vibration. According to prototype tests, the vibrations of the spillway guide wall and the dam show synchronization. Thus, this paper presents a new vibration mechanism of associated-forced coupled vibration (AFCV) for the spillway guide wall to investigate the dynamic responses and reveal coupled vibrational properties and vibrational correlations. Different from conventional flow-induced vibration theory, this paper considers the spillway guide wall as a lightweight accessory structure connected to a large-scale primary structure. A corresponding simplified theoretical model for the AFCV system is established, with theoretical derivations given. Then, several vibrational signals measured in different structures in prototype tests are handled by the cross-wavelet transform (XWS) to reveal the vibrational correlation between the spillway guide wall and the dam. Afterwards, mutual analyses of numeral simulation, theoretical derivation, and prototype data are employed to clarify the vibration mechanism of a spillway guide wall. The proposed mechanism can give more reasonable and accurate results regarding the dynamic response and amplitude coefficient of the guide wall. Moreover, by changing the parameters in the theoretical model through practical measures, the proposed vibration mechanism can provide benefits to vibration control and structural design.
Jijian Lian; Yan Zheng; Chao Liang; Bin Ma. Analysis for the Vibration Mechanism of the Spillway Guide Wall Considering the Associated-Forced Coupled Vibration. Applied Sciences 2019, 9, 2572 .
AMA StyleJijian Lian, Yan Zheng, Chao Liang, Bin Ma. Analysis for the Vibration Mechanism of the Spillway Guide Wall Considering the Associated-Forced Coupled Vibration. Applied Sciences. 2019; 9 (12):2572.
Chicago/Turabian StyleJijian Lian; Yan Zheng; Chao Liang; Bin Ma. 2019. "Analysis for the Vibration Mechanism of the Spillway Guide Wall Considering the Associated-Forced Coupled Vibration." Applied Sciences 9, no. 12: 2572.
Due to impinging jets, the hydraulic load in a plunge pool can be very large and may cause serious damage to the slope and bottom protection structures. Conventional research mainly focuses on the stability of the plunge pool floor, and studies on slope protection safety are still lacking. Based on the Wudongde project, a physical model (that does not consider the plunge pool floor) was established. A series of experiments were conducted to investigate the protective measures for slope protection. Experimental results showed that the high seepage pressure on the back surface of the slope lining plate and poor correlation between the fluctuating pressures on both plate surfaces may cause large pressure differences that seriously threaten the stability of the slope lining plate. Therefore, a self-drainage slope protection structure was proposed to reduce the hydraulic load on a slope lining plate. It must be noted that the slope lining plate with the most violent water level fluctuation and adverse operating conditions (when the drainage system and part of the waterstops were invalid) were considered in the model tests. Test results indicated that self-drainage slope protection could enhance the synchronism of the pressure and water-level fluctuations on both plate surfaces. Therefore, the proposed slope protection structure could effectively reduce the total pressure on the plate and significantly increase the operational safety of the plunge pool.
Bin Ma; Shuai Liang; Chao Liang; Yijia Li. Experimental Research on an Improved Slope Protection Structure in the Plunge Pool of a High Dam. Water 2017, 9, 671 .
AMA StyleBin Ma, Shuai Liang, Chao Liang, Yijia Li. Experimental Research on an Improved Slope Protection Structure in the Plunge Pool of a High Dam. Water. 2017; 9 (9):671.
Chicago/Turabian StyleBin Ma; Shuai Liang; Chao Liang; Yijia Li. 2017. "Experimental Research on an Improved Slope Protection Structure in the Plunge Pool of a High Dam." Water 9, no. 9: 671.
An effective approach to simulate the multi-support earthquake underground motions is proposed in this paper and the key factor for this approach (i.e. underground cross-correlation function) is presented in advance and elaborated. Previous studies are mainly focused on the multi-support ground motions due to the absence of the necessary conditions to simulate underground motions, i.e., underground power spectral density (PSD), underground response spectrum and, especially, underground cross-correlation function. In this paper, the underground PSD and response spectrum are firstly derived and the cross-correlation function between the underground motions at positions with different horizontal and vertical coordinates is further deduced. The physical meanings of the parameters in this approach are explicitly clarified. Moreover, a program for generating the multi-support earthquake underground motions is developed and the reliability of the generated underground motions is verified. Finally, a two-span bridge is taken as an example to investigate structural responses under multi-support earthquake underground excitations. Numerical results show that the dynamic responses under multi-support earthquake underground motions are significantly different from those under multi-support earthquake ground motions. Results indicate that the simulation of multi-support earthquake underground motions is significant for both study and engineering application.
GuoHuan Liu; Jijian Lian; Chao Liang; Mi Zhao. An effective approach for simulating multi-support earthquake underground motions. Bulletin of Earthquake Engineering 2017, 15, 4635 -4659.
AMA StyleGuoHuan Liu, Jijian Lian, Chao Liang, Mi Zhao. An effective approach for simulating multi-support earthquake underground motions. Bulletin of Earthquake Engineering. 2017; 15 (11):4635-4659.
Chicago/Turabian StyleGuoHuan Liu; Jijian Lian; Chao Liang; Mi Zhao. 2017. "An effective approach for simulating multi-support earthquake underground motions." Bulletin of Earthquake Engineering 15, no. 11: 4635-4659.