Journal of Hydroelectric Engineering

水力发电学报

Office Online

Included Databases

The journal is included in the following databases:
(i)Scopus,
(ii)The Chinese Science Citation Database Source Journals,
(iii)The Chinese Science Journal Abstract Database,
(iv)The Chinese Science and Technology Papers Statistics and Analysis Database,
(v)China Newspaper Subscription Guide Information Database,
(vi)Chinese Academic Journals (CD).


2018 Vol. 37, No. 8 Published: 2018-08-25

	1	Prediction of rockfill dam material watering volume based on chaotic time series and random forest regression
		ZHONG Denghua, TIAN Geng, GUAN Tao, CUI Bo, YAN Yuling
		DOI: 10.11660/slfdxb.20180801
		Watering dam material in the compacting operation of rockfill dams has been a general practice to improve compaction quality. However, in the previous studies of the watering control, several questions are left unanswered, such as how to control the water volume accurately and how meteorological factors influence dam material moisture content during the construction process. Consequently, operation at the compaction starting stage is difficult to meet the requirement of design moisture content. To control the watering volume effectively, this study develops a model to predict the change of dam material moisture content considering meteorological factors, using chaotic time series and random forest regression to accurately control the watering volume. It focuses on three aspects: (1) using chaotic time series to make short-term prediction of meteorological information in a given time period; (2) developing a prediction model of moisture content change based on the random forest regression to predict the nonlinear variations in moisture content caused by meteorological factors, and validating the prediction accuracy using the ten-fold cross-verification; (3) accurately calculating the watering volume based on the predicted moisture content, the initial moisture content of dam material, the design moisture content, and the mass of dam material. Based on a practical project and its rolling and transport monitoring systems, our method is compared with the existing watering technique and verified in terms of effectiveness and accuracy. It is thought to be useful to science-based fine control on the watering volume of rockfill dam material.
		2018 Vol. 37 (8): 1-12 [Abstract] ( 196 ) PDF (1228 KB) ( 303 )

	13	Experimental study on wetting characteristics of rockfill materials by triaxial tests
		ZHANG Yanyi, XU Zeping, DENG Gang, WEN Yanfeng, YU Shu, WANG Xiaohui
		DOI: 10.11660/slfdxb.20180802
		Based on the single-line wetting method, wetting tests on mixed sandstone and slate materials are performed using a middle-scale triaxial apparatus. According to the condition of spherical stress and deviatoric stress, the wetting deformation law of rockfill materials is mainly studied. The test results show that the spherical stress and deviatoric stress are the main influencing factors of wetting volume strain and wetting shear strain respectively. The wetting volume strain and stress ratio shows the linear relationship preferably, and the wetting shear strain and stress ratio shows the power function relationship preferably. According to the results, a wetting model and corresponding parameters are initially proposed. The research results are thought to be helpful for the relevant wetting study of rockfill materials.
		2018 Vol. 37 (8): 13-19 [Abstract] ( 121 ) PDF (439 KB) ( 380 )

	20	Hybrid forecasting model for non-stationary runoff based on regularized extreme learning machine
		SUN Na, ZHOU Jianzhong
		DOI: 10.11660/slfdxb.20180803
		In this study, a novel hybrid model, named as ES-RELM, based on ensemble empirical mode decomposition (EEMD), sample entropy (SE), and regularized extreme learning machine (RELM), is developed for daily runoff forecasting featured with nonlinearity and non-stationarity. To extract more reliable information from runoff time series, EEMD-SE is used to decompose the runoff series to a set of sub-series with different complexity, then each sub-series is forecasted independently by a different RELM model, and finally all the sub-series forecasts are combined into an overall forecast of the runoff time series. It is applied in a case study to forecast the daily runoff at Pingshan station, a control station of the lower Jinsha River, and compared in detail with nine other models. Results indicate that our ES-RELM effectively improves the accuracy of daily runoff forecasting and is an efficient, stable forecasting model, thus laying a basis for high-precision real-time runoff forecasting.
		2018 Vol. 37 (8): 20-28 [Abstract] ( 201 ) PDF (805 KB) ( 292 )

	29	Random walk simulations of scalar mixing in vertical two-dimensional water waves
		WU Xuefei, CHEN Yongcan, LIANG Dongfang
		DOI: 10.11660/slfdxb.20180804
		This paper applies a random walk method to simulate scalar transport and dispersion in vertical two-dimensional wave flows. First, this Lagrangian model is verified against an idealized problem involving unsteady shear flows, and a good agreement between the simulated and analytical values of dispersion coefficient and demonstrates its validity. Then, flow velocities and water surface profiles of the water waves are formulated based on the linear and second order Stokes wave theories. The wave flows and their longitudinal dispersion coefficients are numerically simulated and compared between the two theories, showing high accuracy of the random walk method. We also discuss the choice of the control parameters in the model, such as particle number and time step, for a good balance between the computational cost and accuracy. Finally, parameter sensitivity is analysed. We find that longitudinal dispersion coefficient is, as expected, inversely proportional to diffusion coefficient or wave period, while it increases with the increase in water depth and wave height.
		2018 Vol. 37 (8): 29-37 [Abstract] ( 177 ) PDF (940 KB) ( 351 )

	38	Advances in stereoscopic particle image velocimetry
		CHEN Qigang, ZHONG Qiang
		DOI: 10.11660/slfdxb.20180805
		Stereoscopic particle image velocimetry (SPIV) is a non-intrusive technique for measuring the instantaneous three-dimensional velocity vectors on planar domains of fluid flows. Compared with the classical PIV method, it is able to resolve the out-of-plane velocity component and avoid the influence of perspective errors on in-plane velocity components. This paper discusses the recent advances in developing and applying the SPIV method, focusing on stereoscopic configuration, imaging system calibration, methods for velocity reconstruction, and measurement errors induced by misalignment between calibration plane and laser sheet. And optimum performance of the state-of-the-art SPIV systems, together with factors influencing measurement accuracy and spatial resolution, is summarized. To illustrate the capability of SPIV in hydrodynamic research, we give two typical applications to the flows around complicated bodies and their turbulent coherent structures, and briefly discuss the SPIV methods for volumetric measurements.
		2018 Vol. 37 (8): 38-54 [Abstract] ( 340 ) PDF (899 KB) ( 590 )

	55	Numerical investigation on backwater characteristics of oblique river crossing bridge piers
		XU Dong, YANG Haitao, WANG Di, JI Chunning, BAI Yuchuan, JI Zezhou
		DOI: 10.11660/slfdxb.20180806
		A river crossing bridge may induce backwater owing to the flow resistance generated by its piers, which may consequently affect river flood discharging. In the field of bridge and culvert hydrology, a large body of previous studies concerns backwater calculations for the bridges orthogonal to river channel, but still lacking are the theories or empirical formulas applicable to oblique river crossing bridges that involve complicated flow structures beyond their applicability. This study develops a mathematical model for the two-dimensional depth-integrated flows to simulate bridge backwater, and verifies it through a flume experiment. Based on numerical simulations, hydrodynamics and characteristics of the backwater in river channels with oblique crossing bridges are examined, focusing on analysis of the maximum backwater height varying with bridge pier size, crossing angle, and inflow velocity in the cases of flow blockage factor in a range of 10% - 40%. Simulation results show that at a fixed blockage factor, the maximum backwater height increases and then decreases with the increasing oblique angle. Oblique crossing may induce a deflection of the river flow, leading to significant asymmetry of the velocity distribution.
		2018 Vol. 37 (8): 55-63 [Abstract] ( 243 ) PDF (1883 KB) ( 387 )

	64	Characteristics of sediment accumulation in the waterway of Xiuying harbor district, Haikou Port
		LIU Xiaoqiang, YANG Yanhua
		DOI: 10.11660/slfdxb.20180807
		Based on the measured terrain data in different periods, this paper presents a comparative analysis on the general characteristics of siltation and its spatial-temporal distribution over the waterway in the Xiuying Harbor District, Haikou Port. We discuss the influencing factors and major causes of sediment accumulation in this waterway, predict the possibility and trend of severe siltation in future, and suggest engineering countermeasures for siltation reduction. We conclude with the followings. The spatial and temporal distribution of deposits over the waterway is non-uniform, spatially characterized by stronger siltation in its nearshore channel than open sea channel, and stronger in its channel sideline than mid-channel, and temporally characterized by a risk of strong short-term siltation. Its main causes are intrusion of the bottom sediment-water mixture with high concentration caused by heavy storm waves, transport of the side slope sediment into the channel, collapsing of side slopes, settling of suspended sediment in the water body, and construction of artificial islands. To reduce siltation, we suggest constructing sand-proof embankment, reducing the waterway side slopes, and increasing silting depth, among other engineering measures.
		2018 Vol. 37 (8): 64-74 [Abstract] ( 168 ) PDF (2426 KB) ( 430 )

	75	Overview on digital construction in water conservancy and hydropower engineering
		YANG Shunqun, GUO Lili, LIU Zengqiang
		DOI: 10.11660/slfdxb.20180808
		With the development of engineering projects in water conservancy and hydropower industry, building information modeling (BIM), big data and intelligent technology find very broad application in this industry. Since its initial digital construction, a large number of applications have been accumulated in all the stages of a project life cycle – design, construction, and operation management ? forming a certain application scope and depth. This paper summarizes the representative digital application cases in large and medium-sized water conservancy and hydropower projects in China and abroad covering the stages of design, construction, and operation management, analyzes the status quo and existing problems, and gives an outlook on the developing trend, so as to help further integration of digitalization and information technology into the industries.
		2018 Vol. 37 (8): 75-84 [Abstract] ( 418 ) PDF (2185 KB) ( 578 )

	85	Mechanism of inertia and viscosity effects on concrete strength under dynamic loading
		ZHENG Dan, WANG Hailong, LI Qingbin
		DOI: 10.11660/slfdxb.20180809
		Based on an analysis of real stress in concrete specimens, mechanisms of inertia and viscosity effects on the dynamic properties of concrete material are discussed in this paper. The inertia effect under dynamic loading is identified using methods of single degree of freedom and multi-degree of freedom through theoretical analysis and numerical simulation; the viscosity effect is examined on the basis of viscous action of free water in concrete. We also analyze and discuss the empirical formula for calculating the increase in concrete strength under dynamic loading, the phenomena of aggregate fracture and multi-crack failure observed in dynamic experiments, and other factors such as concrete strength and initial static load, so as to help conduct laboratory dynamic experiments more effectively and obtain more accurate parameters for structure dynamic analysis.
		2018 Vol. 37 (8): 85-93 [Abstract] ( 129 ) PDF (2185 KB) ( 215 )

	94	Deformation coordination analysis of RCC gravity dams with functionally graded structures
		LI Mingchao, SHEN Yang, ZHANG Mengxi, XU Na
		DOI: 10.11660/slfdxb.20180810
		Damage, stripping and other unfavorable phenomena often occur at the interface of a high roller compacted concrete (RCC) gravity dam where exists a mutation in material characteristics, threatening dam safety to a certain degree. In this work, to avoid leakage problems and improve deformation coordination, we arrange a transition layer using new impervious material HIAC between the impervious layer and the main body of RCC dam, and design three schemes of rectangular, two-step and three-step transition for this functionally graded structure. We examine spatial variation in the elastic modulus of the transition layer from the perspective of deformation coordination, and evaluate the stress and deformation in the whole structure and material interface of the dam using the contact analysis theory. Results show that when the elastic modulus of the transition layer is higher than that of the main body RCC, the principal tensile stress in the dam is at a low level and the HIAC and RCC materials are well coordinated in their normal and tangential deformation. The present study recommends the three-step transition structure that should have an elastic modulus not lower than the main body RCC. The concept of deformation coordination developed in this study is useful and would provide a new angle for evaluation of the construction and operation of RCC gravity dams.
		2018 Vol. 37 (8): 94-102 [Abstract] ( 193 ) PDF (2710 KB) ( 275 )

	103	Acceleration-based safety factor calculation of underground tunnels
		JIE Yuxin, LI Weihan, ZHANG Bin
		DOI: 10.11660/slfdxb.20180811
		For the underground tunnel, it is difficult to evaluate its stability using the classical analysis method applicable to soil slopes, since its failure surface and failure mode are very different from those of the slopes. In this paper, incorporated with the concept of strength reduction, the approach of calculating acceleration is extended to evaluation of the safety factor of underground tunnels, which is defined as the reduction factor that minimizes the magnitude of acceleration. We generate the failure surface using a smooth continuous curve expressed in polar coordinates, and adopt ant colony optimization for continuous domains to search the minimum safety factor and critical failure surface. Thus, what we are developing is actually a new explicit method for calculating the acceleration-based safety factor of underground tunnels. It has the same theoretical basis as those for calculating the safety factor of slopes, and is shown to be effective through a case study of the stability analysis of an underground tunnel.
		2018 Vol. 37 (8): 103-110 [Abstract] ( 171 ) PDF (1960 KB) ( 249 )

	111	Compressive strength analysis and microscopic characterization of basalt fiber reinforced concrete
		GAO Zhen, CAO Peng, SUN Xinjian, ZHAO Yawei
		DOI: 10.11660/slfdxb.20180812
		This paper reports a study on basalt fiber reinforced concrete (BFRC) combining field test, scanning electron microscope (SEM), and numerical simulation, focusing on the mechanism of basalt fiber influencing concrete compressive strength. The influence of fiber content and fiber length is experimentally observed by conducting compressive tests on samples at different ages, and its SEM data are used to analyze the microstructure. We develop a mechanics model of concrete damage at the microscopic level based on the Mori-Tanaka algorithm and the progressive damage theory of continuous medium, and use it to examine the coupling effect of different fiber contents and different fiber lengths on the compressive strength. To verify its feasibility, the simulation results are compared with our experimental measurements and both agree well. The results show that adding basalt fiber to concrete improves compressive strength and the fiber length of 6mm is better. SEM images show that the phenomenon of fiber adhering and the weak layer between the fiber and the interface have an adverse effect on compressive strength, but the resistance of fiber against cracking leads to a considerable increase in compressive strength.
		2018 Vol. 37 (8): 111-120 [Abstract] ( 324 ) PDF (1559 KB) ( 439 )