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Articles in press have been peer-reviewed and accepted, which are not yet assigned to volumes /issues, but are citable by Digital Object Identifier (DOI).
Study on water resources carrying capacity of ecological diversion irrigation district in the lower reaches of the Yellow River
DU Xuefang, LI Yanbin, ZHANG Xiuyu
 doi: 10.12170/20200209001
[Abstract](14) [FullText HTML](12) [PDF 648KB](0)
Abstract:
The construction of ecological irrigation area in the Yellow River Basin is an important part of the current ecological civilization construction. Based on the theory of water resources bearing capacity of ecological irrigation area as the research basis, the fuzzy set pair analysis method is used to comprehensively evaluate the water resources carrying capacity of typical irrigation areas in the lower Yellow River in this paper. The evaluation results show that water resources carrying capacity was not optimistic in Dagong Irrigation District from 2010 to 2013 and it witnessed a great improvement in the nearly two-thirds district from 2014 to 2016. It was until the year of 2017 that Dagong Irrigation District satisfied its overall water resources carrying capacity.
Preparation and properties of new type low-temperature early strength accelerator
ZHANG Feng, BAI Yin, CAI Yuebo
 doi: 10.12170/20190320003
[Abstract](8) [FullText HTML](5) [PDF 887KB](0)
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The traditional early strength components have not met the requirements of green and high performance concrete, especially in the long-term mechanical properties and durability. The low temperature early strength performance of the existing early strength accelerators is relatively limited, and the research on the mechanism of early strength or that on its influence on concrete durability is also insufficient. In our research, a new type of low-temperature early strength accelerator, which has no alkali, no chlorine and no sulfate ions, was prepared by using four components of inorganic salt CB, LB, triisopropanolamine and nano-SiO2, and its early strength performance and adaptability were also analyzed. The results show that the effects of the early strength accelerator with the optimal ratio of 0.50% CB+1.00% TIPA+0.20% nano-SiO2+0.30% LB is highly reliable. CB and LB were the key components, which played an important role in improving the strength of mortars at different ages under low temperature curing, and TIPA had a significant effect on the strength enhancement after 3 d, while nano-SiO2 was beneficial to the strength improvement after 7 d. At 5 ℃, the 1 d, 3 d, 7 d and 28 d compressive strengths of the motars mixed with early strength accelerators could be increased by 377%, 98%, 72% and 18% respectively, and the strength development of mortars after 3 d had exceeded the strength development of the contrast samples cured at 20 ℃. Low-temperature early strength accelerator had good adaptability to different types of cement and temperature.
Optimization of reservoir cycling water scheme based on water age to reduce algal bloom risk
YANG Jinyan, XU Yong, ZHOU Jie, WU Shiqiang
 doi: 10.12170/20190226004
[Abstract](3) [FullText HTML](1) [PDF 1291KB](0)
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Water age is the time for water replaced by that from outside. Water age plays an important role in algal bloom in reservoirs and is taken as an ideal tracer which can describe water mixing rate and process. It can yield very effective diagnoses, for example the characterization of the mixing and renewal of water masses, of the fate and mixing of contaminants. In the research, an age simulation method based on dyeing simulation was developed to improve EFDC model. Taking Taicang Second Water Plant reservoir pump house location optimization as an example, reservoir circulating currents and water age were modeled to reduce the water age in order to reduce algal bloom risk. Since the air temperature, water depth and nitrogen and phosphor input are hard to control, to optimize the water age and the cycling currents of reservoir by water intake pump house location optimization is one of the most useful ways to control the risk of algal bloom in reservoir by changing growth inhibition.
Rationality evaluation of the delineation of drinking water source protection areas in the Baishi Reservoir
CHENG Ran, LI Jing, REN Huatang, XIA Jianxin
 doi: 10.12170/20190612002
[Abstract](7) [FullText HTML](4) [PDF 1195KB](0)
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The safety of the water environment in drinking water source areas is of vital importance to the lives and health of people, and is the top priority of ecological protection work. Delineations of drinking water source areas are mainly based on the analogue-empirical method, which cannot reflect the spatial and temporal distributions, or the compliance of water quality indicators in protection areas. In the study, the Environmental Fluid Dynamics Code (EFDC) was used to establish a two-dimensional vertical average model of the Baishi Reservoir. Its hydrodynamic and water environment change processes were simulated. The water age, eutrophication, and law of pollutant migration and attenuation were then analyzed to evaluate the rationality of the drinking water source protection areas as delineated by the analogue-empirical method. Through the verification of water level and storage capacity curves, and the verification of three typical annual water-level corresponding curves, RRE < 0.1 and CNSE > 0.85 . The simulation trend of the water quality simulation curve is consistent with the measured data, and the model is reliable. It is found that the average water ages in front of the dam are 304.4 d, 656.4 d, and 673.2 d, under the three typical annual conditions of high flow year, median flow year, and low flow year, respectively. The reservoir has long hydraulic exchange periods and is prone to eutrophication. The attenuation process of pollutants is simulated under the above three hydrodynamic conditions and the boundary conditions of the designed pollutants. The results demonstrate that the water quality of the water inlet is generally up to the standard, although the ammonia nitrogen in the high flow year exceeds the standard in the water inlet. The simulation results also show that the delineations of all water areas below the 116 m water level as the first-grade protection areas can meet the water quality requirements of the water intake. The delineation of drinking water source protection areas is therefore reasonable.
Indoor simulation test of ice temperature expansion force and analysis of related factors
WANG Enliang, LENG Yupeng, HAN Hongwei, XIAO Yao, FU Xiang
Accepted Manuscript  doi: 10.12170/20191009001
[Abstract](9) [FullText HTML](7) [PDF 1184KB](1)
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The winter climate in Northeast China is cold. The ice cap of hydraulic structures such as rivers, canals and reservoirs in winter will produce static ice load acting on hydraulic structures. With the increase of temperature, ice cover plate produces ice temperature expansion force, which will cause damage to hydraulic structures in the field. Due to the long period of field observation and various conditions limiting field observation, in order to study the ice temperature expansion force and influencing factors of ice sheet, the indoor simulation test of ice temperature expansion force was carried out in the low-temperature simulation experiment pool, and the relevant influencing factors such as ice temperature and ice thickness were analyzed. The results show that the expansion force of ice temperature is produced at the stage of temperature rise, and with the increase of temperature, the expansion force of ice temperature tends to increase. When the expansion force of ice temperature reaches its peak, the ice temperature is -1.9 ℃ and the ambient temperature is close to 0 ℃, which is consistent with the field observation results. The maximum expansion force of ice temperature in laboratory test was 118.7 kPa, and the peak value of ice temperature expansion force appeared at 3.5 cm of ice sheet. The maximum ice thickness of the test was 10.65 cm, indicating that the operation point of ice temperature expansion force was at 1/3 of the maximum ice thickness, and the distribution of ice temperature expansion force first increased and then decreased along the distribution of ice thickness.
Discussion on the mechanism of pit collapse by topographic change of the father-son’s caving pond
YING Qiang, ZHANG Xingnong, LUO Longhong, SU Changcheng, JIA Dongdong
Accepted Manuscript  doi: 10.12170/20190425002
[Abstract](13) [FullText HTML](6) [PDF 931KB](1)
Abstract:
The pit collapse is a sloop failure that involves the interaction of water and soil. Its formation mechanism is still not fully understood because of its rapid development and difficult observation underwater. A typical collapse occurred at the entrance of the left branch of Hechangzhou Island in 2012 in the lower Yangtze River, which is a reoccurring failure with a father-son’s caving pond, is chosen as a case study by comparing the topographic changes of main channel near the mouth of the pond in the past four years before the son’s collapse. It is shown that there was siltation in the main channel and not erosion which is inconsistent with the common situation. The topography changes of the pond upstream bend between 2011 and 2012 indicates that the pit collapse can occurred when the riverbed of a shallow trough within a hydrological year was scoured. Before and after the occurrence of the son’s collapse, the bending topography of the downstream side of the father's scour pools did not change much, which indicated that the sediment generated by the pit collapse moved from the bottom to the lower level, and had little effect on the relatively high riverbed topography around it.
Resistance coefficient equation for permeable tetrahedron frames
LIU Jianhua, YANG Zhonghua, LI Da, LI Ming
 doi: 10.12170/20190216001
[Abstract](2) [FullText HTML](1) [PDF 719KB](1)
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The study of resistance coefficient for permeable tetrahedron frames (PTF) with seepage effect is of practical significance. PTF were taken as large-scale roughness in this research. Using the penetration depth, a two-layer dynamic model was established for the turbulent flow over large-scale roughness. The flow was divided into two layers, the permeable layer and the free-flow layer, along the water depth. Considering roughness area and seepage effect in the bottom, the resistance equation was derived with this two-layer model. Flume experiments of PTF were conducted and results present that the vertical distribution of longitudinal velocity is S-shaped when frames are laid. The key parameter, shape factor, was calibrated by 47 sets of data with the Reynolds number ranging from 25 000 to 50 000.
Study on early performance of rapid hardening sulphoaluminate cement-based sealing material
FAN Chengwen, BAI Yin, LI Ping
 doi: 10.12170/20190321001
[Abstract](4) [FullText HTML](7) [PDF 843KB](0)
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In order to develop materials suitable for rapid plugging of concrete leakage defects under pressure, we use vinyl acetate-ethylene copolymer (VAE) to modify rapid hardening sulphoaluminate cement (R·SAC). Employing rheometer, R·SAC’s rheologic property was revealed by testing its viscosity law which varies with time. The early performance of R·SAC-based materials was unveiled by combining the testing results of R·SAC’s mechanical property by means of anti-flexural and anti-pressure test and adhesion test on “8”-shaped model with analysis of scanning electron microscope (SEM). The study shows that maintainable time of initial viscosity of R·SAC is about 40 minutes, whose viscosity surges with exponential rate later. With an addition of VAE, plugging material’s ability to resist leaking water pressure improved accompanied by an increase of R·SAC’s initial viscosity, an acceleration of mutational site and an remarkable leap of viscosity’s growing rate. The most obvious phenomenon above occurs by adding 4% VAE into the material. When the content of VAE ranges from 3% to 4%, the increase of R·SAC’s early anti-flexural strength varies from 15% to 21% and anti-pressure strength decreases accordingly. The increase of flexural-press ratio demonstrates that the flexibility of the modified R·SAC achieves improvement. When the content of VAE reaches 4%, 1 d bonding strength hits its maximum with a 121% bonding strength growth compared with the control group. Analysis from SEM illustrates that dense lap structures are formed among interior granules of R·SAC and thus the material’s ability to plug leakage defects gets substantive progress.
Dynamic analysis of multi-compartment bucket foundation based on boundary model
WU Shiyang, CAO Yongyong
 doi: 10.12170/20190523001
[Abstract](5) [FullText HTML](2) [PDF 1248KB](0)
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As the infrastructure of offshore wind power developed in recent years, the stability of the multi-compartment cylindrical foundation impacts on the fan’s safety greatly. In order to study the stability of cylindrical foundation under extreme wind load, the AR autoregression linear filtering method were applied to simulate the fluctuating wind speed spectrum in the paper, by means of the boundary surface elastioplastic dynamic constitutive model and the large-scale finite element analysis software ABAQUS to analyze the 3D dynamic value, and study the settlement development of the structure under the random wind load, dynamic response and the pore pressure change of surrounding soil. The study indicated: As the loading continues, the cylindrical horizontal displacement, rotation angle and vertical displacement all trended to increase slowly, meanwhile, the cylindrical top horizontal displacement was much larger than that in the end; affected by the subdivision plate, the pore pressure of the soil in the foundation developed slowly and was smaller than that outside the foundation; along the cylindrical diameter, the closer to the cylinder wall, the greater the pore pressure was; on the out side of the foundation, the pore pressure of the soil decreased gradually with the buried depth, and finally tended stable; the stress path of soil was gradually close to the critical state line, but did not reach the failure standard.
Security evaluation of water-energy-food nexus system in China
LIU Jing, LIU Cuishan, LI Xiao, WANG Guoqing, BAO Zhenxin
 doi: 10.12170/20190603009
[Abstract](14) [FullText HTML](11) [PDF 951KB](2)
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In order to guarantee the safety of China's water, energy, and food, the pressure state response model was applied to evaluate the safety of water-energy-food nexus system in China from 2007 to 2016. The 16 representative indexes were selected to construct a collaborative safety evaluation index system of water-energy-food nexus. The analytic hierarchy process (AHP) was used to determine the index weight. Based on data during 2007—2016, the safety of water-energy-food nexus system was assessed at national and provincial levels. The results show that the collaborative security degree of water-energy-food nexus system in China has been rising in the past 10 years. The comprehensive collaborative security degree of water-energy-food nexus system in Beijing, Tianjin and Shanghai is higher than others. However, Ningxia, Xinjiang and Chongqing have low degree of collaborative cooperative security due to shortage in water resources. The level of comprehensive collaborative security in most provinces is higher during 2012—2016 than that in 2007—2011.
Calculation and analysis of water footprint of hydropower stations in Yalong River Basin
YU Lei, JIA Benyou, WU Shiqiang, WU Xiufeng, XU Peng, WEI Jinli
Accepted Manuscript  doi: 10.12170/20190603003
[Abstract](15) [FullText HTML](9) [PDF 740KB](0)
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In order to quantify the effect of hydropower development and utilization for local water resources, this paper introduces the concept of water footprint, taking the cascade reservoirs in the Yalong River Basin as the research object, selecting the total water consumption method, using the measured data for many years, and considering three system space boundaries to calculate the water footprint of the seven hydropower stations. The results show that water footprint of the seven hydropower stations in the Yalong River Basin ranges from 0.01 to 2.91 m3/GJ and the average water footprint is 1.13 m3/GJ, which is smaller than other water footprints of global and national spatial scales. It also means that the utilization efficiency of water resource of hydropower development and utilization in the basin is higher than that of other regions and river basins. The water footprint of the hydropower station is mainly affected by the energy efficiency factor (water surface area of the reservoir area per unit installed capacity) and the topographic factor (the water surface area of the reservoir area and the average water depth ratio of the reservoir area), and the correlation indexes are 0.950 7 and 0.783 1, respectively. However, the evaporation depth and meteorological factors (rainfall and temperature) have less impact on the water footprint of hydropower stations. The water footprint of the hydropower station is related to the setting of the boundary of the space system. It is necessary to select the appropriate space system boundary according to the actual operation of the hydropower station.
Analysis of collapsing gully erosion mechanism in southeast Hubei under rainfall conditions based on ABAQUS software
MA Pengfei, XIA Dong, XU Wennian, YANG Wei, LUO Ting
 doi: 10.12170/20181228004
[Abstract](9) [FullText HTML](6) [PDF 2062KB](1)
Abstract:
Aiming at investigating the instability mode and dynamic response of the seepage field of the collapse wall under the combined interaction of groundwater uplift and different types of rainfall duration, on the basis of mechanical index parameters of rock and soil layers of the collapsing hill obtained from in-situ observation and relevant geotechnical physical model tests, we attempt to explore the process and mechanism of hydraulic factors affecting the collapsing gully erosion under a single rainfall from the angle of coupling seepage domain and stress field of collapse wall through performing plenty of numerical experiments. The FEM analysis results indicate that the failure mode of the collapse wall in successive light rain environment belongs to the combination of local erosion of the middle and lower soil layers of collapse wall and integral-sliding failure of the soil body above the sandy soil layer, and in short-term heavy rain environment, the failure mode of the collapse wall is manifested by the (layered) flow sliding of the shallow slope surface. Whereas, no matter what type of rainfall, there must be an earlier stage (lasting for a long time) of precipitation that causes the sandy soil layer of the collapse wall to be eroded by water to form a concave cavity. Until the depth of the concave cavity reaches an ultimate value, the volume of concave cavity will no longer expand, and it will turn into a later stage of precipitation before the collapse wall is in critical failure status. The seepage areas generated by rainfall infiltration mainly occur in the shallow soil layers of the collapse wall, as a result, the shear strength properties of the shallow soil unceasingly weaken and the maximum shear stress increases obviously. With the prolongation of rainfall duration, a transient saturated zone appears in the surface soil layer of the catchment slope and the wetting peak (zero pressure surface) gradually moves towards the deep strata of the collapsing gully wall. The groundwater level line gradually rises and thus causes pipe erosion to the bottom of the sandy soil layer by (downward) outcropping springs. The analysis results are in good agreement with the field observation phenomena.
The future water resources regime of the Yellow River basin in the context of climate change
WANG Guoqing, QIAO Cuiping, LIU Minglu, DU Furan, YE Tengfei, WANG Jie
 doi: 10.12170/20200216001
[Abstract](24) [FullText HTML](18) [PDF 1161KB](0)
Abstract:
The future water resources prediction is a fundamental work for water resources planning and sustainable utilization. Based on the RCPs climate change scenarios of 7 GCMs projections, the variation trend of temperature and precipitation in the coming decades over the Yellow River basin were investigated, and the future water resources of the Yellow River basin was simulated by using RCCC-WBM model and the downscaled climate change projections. The results show that: (1) Temperature will probably continue to rise significantly with a linear rising rate of 0.24~0.35 ℃/(10 a); (2) The future precipitation will likely increase slightly, with a higher uncertainty; (3) As a result of climate change, water resources over the Yellow River basin will probably decrease in the coming decades, which will aggravate conflict of water supply and demands to some extent. Uncertainty and the induced-risk in future water resources prediction is a major issue which needs to be enhanced in further study.
Water quality evaluation in huangshui mainstream based on Interval type Bayesian model
LU Dan, GENG Zhaoke, MIN Min, WANG Siyang
 doi: 10.12170/20191220002
[Abstract](13) [FullText HTML](10) [PDF 629KB](0)
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Traditional water quality evaluation methods are greatly affected by subjective factors. In order to further understand the water quality of Huangshui mainstream in the upper reaches of the Yellow River, the Interval type Bayesian model was used to evaluate water quality based on the monitoring data of BOD5, COD, NH3-N, TP and Cr6+ of 12 sections in the Huangshui mainstream from January to December 2018. The results show that the Interval type Bayesian model can directly and accurately reflect the water quality change of monitoring sections, which basically accords with the trend in water quality of “good water quality—deteriorated water quality—improved water quality” from the upstream to the downstream of Huangshui River. The sections with poor water quality are mainly located in the urban concentrated reaches with concentrated population and developed industries, and the excessive pollution should be the main reason for the deterioration of water quality. In the future, these reaches should be selected as the priority areas for water pollution control and water quality monitoring in Huangshui River.
Numerical analysis of regulation schemes of continuous bending and multi-beach dangerous channels in the upper Yellow River
LI Jian, WANG Pingyi, XU Baiqiang, HE Xiaohan, WANG Meili
 doi: 10.12170/20190901001
[Abstract](11) [FullText HTML](5) [PDF 747KB](0)
Abstract:
Natural river channels generally cannot meet the actual requirements of local navigation. Therefore, the waterway regulation is the key technology to meet people's requirements. Currently, the regulation technology of the inland waterway in China is very mature, while there is still scarce research on river channels with continuous bends and abundant dangerous beaches. This research is based on the river channel with beaches in the lower reaches of Changsheng wharf in Baiyin City from the upper reaches of the Yellow River. The river channel belongs to a continuous curved channel. There are many beach bodies in this river channel with complex water flow conditions, which seriously affects the safe navigation of ships. Taking the numerical simulation as the research means, this paper establishes a two-dimensional mathematical model, analyzes the hindering factors of the river channel, demonstrates the rationality of the regulation scheme, and determines many regulation methods, including filling trough, cutting nozzle, dredging, and constructing submersible dam, etc. The regulation effect is very obvious. The hydraulic factors reach the navigation index, and the flow conditions are obviously improved, which provides a reference for future regulation projects of the upper reaches of the Yellow River as well as the waterway with similar navigation hindrance characteristics.
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2020, (1): 1-2.  
[Abstract](181) [FullText HTML](110) [PDF 416KB](4)
Abstract:
Model test study on diversion characteristics of river junction in plain river network area
LIU Guoqing, WANG Wei, FAN Ziwu, MU Shousheng, JIA Benyou, WU Jingxiu, DENG Zhao
2020, (1): 1-8.   doi: 10.12170/20190501002
[Abstract](176) [FullText HTML](100) [PDF 1198KB](2)
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This paper takes the South Jiangsu Canal-Li River-Wangyu River Interchange Channel as the research object, based on the verification of the overall one-dimensional river network mathematical model of Jiangsu Taihu area and the local physical model of the South Jiangsu Canal-Li River-Wangyu River intersection, a two-dimensional mathematical model of intersection is constructed. Based on the “16.7” exceeding-historical flood data, the combination of the physical model and the calculation of current intersection angle, the characteristics of the Li River diversion ratio under the conditions of the South Jiangsu Canal-Li River interchange angle are further simulated and multi-factor impact analyses are carried out. The results show that the junction of the South Jiangsu Canal- Li River -Wangyu River is different from the “Y” type or the slanting junction, and the water diversion ratio of the Li River is mainly due to the water level difference between the Wangyu River and the South Jiangsu Canal-Wangyu River, which has little relationship with the discharge flow of the South Jiangsu Canal. The influence of the intersection of the South Jiangsu Canal and the Li River on the diversion ratio of the Li River is not significant. It is mainly because the mouth recirculation zone shrinks the effective over-water width of the tributary, resulting in the actual width of the inlet smaller than the tributary width.
Numerical simulation on flood characteristics under different forest coverage rates of watershed
YAO Yuan, GU Zhenghua, LI Yun, GU Qiaoya, FAN Ziwu
2020, (1): 9-15.   doi: 10.12170/20190501003
[Abstract](221) [FullText HTML](126) [PDF 852KB](14)
Abstract:
In order to study the influence of forest cover change on flood characteristics, a distributed hydrological model of Xiaoxi watershed was established. The parameters of the model were validated and verified by observed hydrologic data and its applicability was also evaluated. Then the seven-day rainfall series was selected and the model was used to simulate the flood process of Xiaoxi watershed with the forest coverage rates ranging from 0% to 100%. The results indicated that changing the forest coverage rates had a great impact on the flood characteristics of Xiaoxi watershed. The greater the forest coverage rate, the more obvious the effect. Compared with non-forest coverage condition, when the forest coverage rates reached the maximum, the flood peak flow was reduced by about 13.2%, the arrival time of the flood peak was delayed for about 4 hours, and the flood duration was extended by about 13 hours. Besides, when the forest coverage rate was less than 40%, there was a very limited reduction effect on the flood peak flow; when the forest coverage rate was more than 40%, an average of 10% increase in forest coverage could lead to 2% reduction of flood peak flow. Moreover, the shape of the flood process showed a trend from a single peak to double peaks with increasing forest coverage rate.
Building and verification of refined hydrology-hydrodynamic model for South Jiangsu Canal and its river networks
YANG Fan, ZHOU Yulin, FAN Ziwu, WU Jingxiu, JIA Benyou, LIU Guoqing, XIE Chen, WANG Chaoyong
2020, (1): 16-24.   doi: 10.12170/20190501001
[Abstract](74) [FullText HTML](46) [PDF 20388KB](7)
Abstract:
Passing through the abdomen of the Taihu Lake basin from north to south, the South Jiangsu (Sunan) Canal has the functions of navigation, flood control and drainage, irrigation and landscape. In recent years, the water level of the canal has exceeded the historical high level, causing serious disasters along the canal and its surrounding areas. The refined hydrology-hydrodynamic model developed by us can provide technical means and scientific basis for the cause analysis of the high water level of the canal, the decision-making of flood control and drainage, and the benefit evaluation of new and old works. Based on the Infoworks ICM software, the hydrology-hydrodynamic model of the plain river network along the South Jiangsu Canal is built, taking into account the polder area, urban pipeline network and complex underlying surface of the plain river network along the South Jiangsu Canal. In view of the difficulty in determining the boundary of the river system along the South Jiangsu Canal, the study area of the model has been extended to 21,600 km2. The model is validated and calibrated using the actual rainfall, water level and water conservancy work operation data in the flood seasons of 2015 and 2016. The verification results show that the refined hydrology-hydrodynamic model for the Sunan Canal has high credibility and can provide a technical support for academic research and engineering application. The Nash coefficients of most hydrological stations are close to 1, and the reliability of the model is high. The determination coefficient results show that the correlation is moderate, and the overall results of the model are credible. At the same time, compared with other areas of the Taihu Lake, the simulation accuracy of the western area of the Taihu Lake is higher. The main reason is that the western area of the Taihu Lake is less intervened by man-made dispatching.
Study on efficiency and mechanism of phosphorus removal from supernatant of anaerobically digested sludge—based on anion exchange and modified hydrotalcite adsorption methods
FU Yuling, YAN Hanlu, WANG Li, CHEN Cheng, CHEN Qiuwen
2020, (1): 25-31.   doi: 10.12170/20190501004
[Abstract](214) [FullText HTML](173) [PDF 1120KB](10)
Abstract:
This study selected supernatant of anaerobically digested ferric phosphate sludge as the research object and investigated the phosphorus (P) removal effectiveness and mechanisms of three types of materials, including strong base anion exchanger (DOWEX66), weak base anion exchanger (IRA402-Cl) and modified hydrotalcite. The experimental results demonstrated that (1) The DOWEX66 showed higher P removal efficiency (33.3%) than IRA402-Cl (14.2%) at the same solid to liquid ratio (3 g/L) because DOWEX66 resin has tertiary amine functional groups with strong binding force to \begin{document}${\rm{H}}_2{\rm{PO}}_4^- $\end{document}; (2) The breakthrough profiles of phosphate uptake by raw DOWEX 66 resin in column test indicated that the breakthrough point of phosphate adsorption was located at around 5 bed volumes, which suggested that anion exchange resin has limited P elimination ability and buffer solution system is beneficial to ion exchange between resin and phosphate; (3) The 300 ℃ calcined hydrotalcite showed efficient P removal ability in the iron and phosphorus concentrated solutions and reached the highest removal ratio of 89.0% ratio at solid to liquid ratio of 2 g/L. The 300 ℃ calcined hydrotalcite also showed good performance in separating iron and phosphorus elements, indicating that modified hydrotalcite can be applied as potential material to remove and to recycle phosphorus from sludge anaerobic digestion supernatant.
Numerical investigation on distribution characteristics of velocities at equal-width open-channel confluences
ZHOU Zhou, ZENG Cheng, ZHOU Jie, WANG Lingling, DING Shaowei
2020, (1): 32-39.   doi: 10.12170/20190501005
[Abstract](296) [FullText HTML](212) [PDF 1329KB](15)
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The confluence of open channel flows is a common phenomenon in water-related projects. The distribution characteristics of flow velocities at the junction are complex and have a direct impact on the design and maintenance of channels. For the velocity distribution characteristics of combining flows, a three-dimensional numerical model of the equal-width open channel confluence was developed with RSM and the VOF method. Based on the measured results of experiment, the model was verified to study the velocity distribution with different combined scenarios in the junction area. The results reveal that: the flow velocity distribution is zone-featured; at the junction, the streamlines blend and the velocity deflects, and a recirculation structure and secondary flow are located downstream. A greater junction angle leads to larger deflection, stronger recirculation structure and stronger secondary flow, which strengthens the characteristic of velocity distribution and brings a greater impact on the walls of channel. A greater discharge ratio leads to a smaller squeezing effect on the water in the main channel and impacts the zone-featured distribution of velocities, which makes the confluence of water smoother and reduces scour on the walls.
A study of hydrodynamic characteristics of resting pools of vertical slot fishway
WANG Xiaogang, LI Yun, HE Feifei, XUAN Guoxiang, WANG Biao
2020, (1): 40-50.   doi: 10.12170/20181130002
[Abstract](192) [FullText HTML](126) [PDF 1582KB](6)
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Several studies have shown that many fishes will be detained in the fishway resting pools, especially in the turning section of the resting pool. A 3D numerical model using the RNG k-ε turbulent closure is applied to study the influences of vertical slot position, resting pool length, and auxiliary baffle placed at the resting pool on the hydraulic characteristics of the resting pools located in the straight section and turning section. The research results show that the turbulent kinetic energy and turbulent energy dissipation rate of the water flow in the resting pools are much lower than those in the ordinary regular pools of the fishway, and the longer the fishway resting pool is, the lower the turbulent kinetic energy and the turbulent energy dissipation rate of the water flow, and the larger the resting space is in the resting pools. The position of the vertical slot of the fishway has little influence on the flow characteristics of the resting pool located at the straight section. It is reasonable that the length of the fishway resting pool specified in the code should be more than twice that of the ordinary pool. For the fishway resting pools located at 29° turning section, the layout of the vertical slot at opposite side is more advantageous, while for the fishway resting pools located at 180° turning section, the layout of the vertical slot at the same side is more advantageous. Due to the existence of a large area of high velocity reverse current zone in the center of the fishway resting pools located at 180° turning section, full attention should be paid to it. Adding an auxiliary baffle in the fishway resting pools can effectively eliminate the large reverse current zone in the center of the pools and greatly increase the areas of the velocity zone, which is worthy of popularization and application.
Hydrodynamic changes in south channel of Yangtze River estuary under topographic variation conditions
QIAN Mingxia, LU Chuanteng, SUN Gaoxia, DING Wei, ZHU Fangjian
2020, (1): 51-58.   doi: 10.12170/20181223001
[Abstract](183) [FullText HTML](109) [PDF 2367KB](1)
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The river channel section of the south channel of the Yangtze River estuary changed alternately in “U” and “W” shapes from 1958 to 2010. Based on the two-dimensional tidal current mathematical model, the hydrodynamic changes under the topographic conditions of the Yangtze River estuary in 1958, 1973, 1997 and 2010 are respectively simulated, and the impacts of topographic changes on the tidal wave transmission and tidal current movement are analyzed. The research results show that the hydrodynamics in the study area (south channel) is closely related to the topographic variation. The tidal range of the south channel reach has gradually decreased, and the tidal wave deformation has gradually intensified since 1958. The tidal current movement is closely related to the development of the Ruifeng shoal. In 1997 when Ruifeng shoal was the largest, the flow velocity of the south channel was distributed in a double pattern. The Changxing waterway was dominated by the high tide, while the other years were dominated by the ebb tide, and the main channel of the south channel was always dominated by the ebb tide. From 1958 to 1973, the diversion ratio of the ebb tide in the south channel decreased significantly, and stablilized after 1973 to about 50%, with little change with the topography.
Three-dimensional numerical simulation of local scour based on spur dikes in a natural river
QI Lan, ZENG Qingda, JI Shunwen
2020, (1): 59-65.   doi: 10.12170/20180920001
[Abstract](261) [FullText HTML](162) [PDF 830KB](22)
Abstract:
In order to study the influences of the spur dike length on the local scour of riverbed in the natural rivers, based on the shape of the natural river channels and the actual layout of the spur dikes, a three-dimensional computational fluid dynamics (CFD) numerical simulation method for the local scour of the spur dike group suitable for the shape of the natural river channel is proposed, and a three-dimensional model for the spur dike group located at the Maliangzi section of the Luanhe River in Hebei Province is established. The shape and erosion depth of the scouring pit in the groin head are numerically simulated by using RNG k-ε model and VOF method which can track the free surface. The shape and scouring depth of the scouring sump are numerically simulated. The numerical simulation results are in good agreement with the measured values, and the reliability of the numerical model is verified. The maximum scouring pit depth and scope of the spur dikes are obviously reduced after adjustment.
Simulation and verification of reservoir fluctuating water level based on immersed boundary method
ZHOU Rui, CHENG Yongguang, WU Jiayang
2020, (1): 66-73.   doi: 10.12170/20180821001
[Abstract](369) [FullText HTML](354) [PDF 930KB](16)
Abstract:
The fluctuation of reservoir water surface has complex flowing boundaries. The ability and effectiveness in processing complex boundary conditions will have a major impact on the sustainable development and utilization of water resources. In order to simulate the large variation of the free surface of the real reservoirs, this research deals with the variation of the free surface of the reservoir by use of the immersed boundary method (IBM), which compares the distribution of the reservoir water temperature, the reservoir drainage temperature and the vertical water temperature distribution in the front of dam, and the results are verified by a simple calculation example. The simulation results show that the method has good feasibility and accuracy, can improve the prediction method for reservoir fluctuating water level, and can be used to study the spatio-temporal variation law of the reservoir water level. And the research results have broad application prospects in dealing with the problems of large variation of the reservoir water surface and can provide a technical support for simulating similar reservoirs in the future.
2D numerical simulation of hydrodynamic characteristics of water flowing around inland river frame wharf in tandem and parallel arrangement
LIU Mingwei, ZENG Liqin, CHEN Gang, SHEN Lilong, MOU Zhizhong, WANG Mingjing
2020, (1): 74-83.   doi: 10.12170/20181204005
[Abstract](252) [FullText HTML](155) [PDF 1650KB](2)
Abstract:
The hydrodynamic characteristics of the flow around the pile-columns directly determine the distribution of the flow force acting on the piles, which is the basis of the flow loads on the inland river frame wharf. Using the computational fluid dynamic (CFD) method, and based on the practical works located at the inland river frame wharf, a two-dimensional numerical simulation model is developed to investigate the hydrodynamic characteristics of the flow around the large diameter four pile-columns arrayed in tandem and parallel or perpendicular to the flow direction. The wake flow field around pile-columns under the conditions of different flow velocities and pile spacings is analyzed systematically. The change law of the flow resistance coefficient, the lift coefficient and the Strouhal number with the flow velocity U and the pile spacing L is revealed. And some studies of the flow field shape and hydrodynamic characteristics of four pile-columns in tandem and parallel arrangement, the influence effects of flow shielding, the influence coefficient of flow shielding and the change of transverse (lateral) influence coefficient at different velocities and the pile spacings are carried out. The results of numerical simulation and analysis can provide some technical references for the calculation of flow loads on the similar pile-columns structures located in the inland river frame wharves.
Geometrical modelling with finite element method and slope effect of geosynthetic reinforced and pile-supported embankments
JIANG Yanbin, HE Ning, XU Binhua, ZHANG Zhongliu, GENG Zhizhou, SHI Beixiao
2020, (1): 84-91.   doi: 10.12170/20181206001
[Abstract](222) [FullText HTML](152) [PDF 1325KB](8)
Abstract:
The finite element geometric modeling methods commonly used for the geosynthetic reinforced and pile-supported embankments include the single pile model (including axisymmetric model and single pile three-dimensional (3D) model), the plane strain model and the full 3D piled embankments model. These models have different characteristics and assumptions, however, few studies have been carried out to focus on the comparison. The geometric modeling analysis is carried out by using the nonlinear finite element software ABAQUS combined with the field testing results. The differences and causes of stress distribution and deformation between the models with hypothesis of large-area surcharge filling and the full 3D piled embankments model with slope are compared and analyzed. The results of numerical model calculation show that the full 3D piled embankments model can best fit the real performance, while both the single pile model and the large-area surcharged full 3D piled embankments model underestimate the settlement. Due to the horizontal displacement and uplift swelling caused by embankment slope, the settlement difference, average stress ratio between pile and soil, the load sharing coefficient of the pile and lateral tensile stress of the geogrid all reach the maximum values under the shoulder region of the embankment. Meanwhile, under the pavement area, all the four parameters of the full 3D model with slope are larger than those of the full 3D piled embankments model with large-area surcharge filling. The numerical simulation results given by this paper can provide a meaningful reference for the geometrical numerical modelling of composite foundation under embankments and the analysis of the three-dimensional slope effect of embankments.
Analysis of strength-deformation behavior of coral sand with different densities and stress levels
HOU Heying, CAO Yongyong, ZHANG Shaodong, GUAN Yunfei
2020, (1): 92-97.   doi: 10.12170/20181210001
[Abstract](205) [FullText HTML](153) [PDF 1078KB](11)
Abstract:
In order to study the influences of density and stress level on the strength and deformation characteristics of the coral sand, a series of triaxial consolidation drained shear tests with different densities and stress levels are carried out using a triaxial apparatus. Based on the experimental study results, the effects of the density and stress level of the coral sand on its stress-strain, volume deformation characteristics and strength characteristics are analyzed. The analysis results show that the specimens with different relative densities all have the dilatancy characteristics, while for the specimens with same initial density, the larger the confining pressure, the less obvious the dilatancy. The initial tangential modulus of the coral sand increases with the increase of the confining pressure and relative density, which can be approximately expressed by a straight line. The relationships between the initial tangent modulus, relative density and confining pressure are established in this paper. The strain at the phase transition point increases with the increase of the confining pressure and decreases with the increase of the relative density. The strength indexes of the coral sand increase linearly with the increase of the relative density, and the relationships between them are established.
Rapid modeling of arch dam structure under CATIA secondary development based on 3DEXPERIENCE platform
LOU Tao, BAO Tengfei
2020, (1): 98-104.   doi: 10.12170/20190124002
[Abstract](181) [FullText HTML](122) [PDF 670KB](4)
Abstract:
An arch dam consists of various curves and surfaces and the structure is complex. It is tedious and time-consuming to model it. In order to facilitate the rapid construction of the arch dam model, improve the modeling efficiency and reduce the duplication of effort in the modeling process, a new method is proposed for constructing the arch dam efficiently and quickly, which is based on CATIA secondary development of arch dam. Based on 3DEXPERIENCE platform, this method applies the object-oriented Python language to connect the CATIA module through the automated interface, and to conduct secondary development for the CATIA module, which takes advantage of the simplicity of Python code. The secondary development program can access the given EXCEL file to get the parameters of the arch dam, automatically create sketches, and then construct solid models to realize the function of building 3D shape in batch. It can reduce the trouble caused by the repetitive work of manual inputting parameters. Meanwhile, the work efficiency can also be improved. For this reason, there is great value of promotion for all. In addition, the 3DEXPERIENCE platform also has the technical characteristics of multi-stage modeling, superposition modeling and correlation modeling, which provides the basis for the realization of parallel collaborative design of models in the three-dimensional environment.
Evaluation method for hidden safety dangers of hydropower construction based on fuzzy neural network
LIU Shuai, SHENG Jinbao, WANG Zhaosheng, YANG Dewei
2020, (1): 105-111.   doi: 10.12170/20181031004
[Abstract](304) [FullText HTML](139) [PDF 532KB](3)
Abstract:
There are many hidden safety dangers and dynamic changes in the construction process of hydropower projects, which is the main reason for the frequent accidents during the construction of hydropower projects. In order to evaluate the degree of the potential safety dangers in the period of construction, an evaluation model for the hidden safety dangers of the hydropower construction is established based on fuzzy comprehensive evaluation and BP neural network. A multi-level with multi-index system for the diagnosis of the hidden dangers during the construction is developed, and five levels, namely major, large, general, small and slight levels, are proposed. Using the example, the hydropower construction is evaluated, the safety hazard level is determined, and the evaluation results are analyzed. The evaluation results of the potential safety dangers show that the hidden safety danger level of the example station is the third level, which conforms to the actual situation of hidden danger investigation. The fuzzy neural network model proposed in this paper has strong operability and can effectively analyze the potential hidden safety dangers during the construction. It has a certain reference value for the investigation of the potential hidden safety dangers in the construction process of hydropower projects.
Development and application of dynamic safety risk analysis system for super-high concrete arch dam
WANG Zicheng, XU Houlei, ZHAO Zhiyong, ZHANG Libing, CHEN Hao, CHEN Yajun, XU Zhiyong
2020, (1): 112-118.   doi: 10.12170/20181201002
[Abstract](901) [FullText HTML](148) [PDF 3221KB](8)
Abstract:
In view of the dynamics and complexity of structural safety risk and the seriousness of accident consequences during the operation and maintenance of the super-high concrete arch dams, a dynamic safety risk analysis system for the super-high concrete arch dam is developed based on the analytic hierarchy process, fuzzy theory and quantitative risk assessment analysis method, by using the SQL Server database and Microsoft Visual C#. NET programming technology. According to the load structure characteristics of the super-high concrete arch dams and the characteristics of various kinds of the safety monitoring instruments and complex layout of the safety monitoring system, a database adapted to different monitoring types and massive safety monitoring data is established. Based on the comprehensive evaluation system of the monitoring data, inspection and geophysical detection for the safety of the super-high concrete arch dam, the probability level of the accident of the super-high concrete arch dam is determined. The economic losses and the impacts on the social environment caused by dam accidents are quantitatively analyzed by means of an equivalent method to determine the loss level. Finally, the risk matrix is used to evaluate the dynamic safety risk level of the super-high concrete arch dam according to the probability level of occurrence of the accident and the loss level caused by the dam accident.
2020, (1): 119-119.  
[Abstract](83) [FullText HTML](72) [PDF 286KB](6)
Abstract:
2020, (1): 120-120.  
[Abstract](96) [FullText HTML](104) [PDF 177KB](12)
Abstract:
Advances in studies of tailing dam break mechanism and process
ZHAO Tian-long, CHEN Sheng-shui
2015, (1): 105-111.  
[Abstract](1787) [PDF 945KB](1332)
Analysis of three-dimensional numerical simulation methods for turbulent flow past circular cylinder
QIAO Yong-liang, GUI Hong-bin, LIU Xiang-xin
2016, (3): 119-125.  
[Abstract](938) [PDF 1367KB](1009)
Analysis of dam-break flood based on HEC-RAS and HEC-GeoRAS
HE Juan, WANG Xiao-song
2015, (6): 112-116.  
[Abstract](763) [PDF 679KB](1138)
Research progress and application of floating breakwater
SHEN Yu-sheng, ZHOU Yi-ren, PAN Jun-ning, WANG Xing-gang
2016, (5): 124-132.  
[Abstract](1071) [PDF 1309KB](594)
Experimental study of distributed optical fiber temperature measurement technology for measuring leakage in embankment dam
HE Ning, DING Yong, WU Yu-long, ZHOU Yan-zhang, LI Deng-hua, HE Bin
2015, (1): 19-27.  
[Abstract](866) [PDF 1877KB](1014)
Comprehensive assessment of plain reservoir health based on fuzzy and hierarchy analyses
YUE Qiang, LIU Fu-sheng, LIU Zhong-qiu
2016, (2): 62-68.  
[Abstract](864) [PDF 872KB](556)
Effects of granite powder fineness and addition on concrete microscopic pores
ZHAO Jing-hui, LIU Fu-sheng, WEI Mei, CHENG Ming
2016, (2): 39-45.  
[Abstract](638) [PDF 1289KB](469)
Property analysis of concrete under coupling action of sulfate and wet-dry cycles
LIU Dao-wei, LIU Ben-yi, LI Xiang-dong, YUAN Jie
2015, (4): 69-74.  
[Abstract](772) [PDF 542KB](679)
Structural design of retaining wall with ecological geo-textile bags and its changes in mechanical properties
ZHU Hai-sheng, CHEN Jian, ZHANG Gui-rong, WANG Wei, FANG Xu-shun
2015, (4): 48-55.  
[Abstract](875) [PDF 2918KB](585)
2D numerical simulation of breach area and coupling simulation of dam breach flood
YANG Zhi, FENG Ming-quan
2015, (1): 7-18.  
[Abstract](1423) [PDF 2043KB](1415)

Supervisor:Ministry of Water Resources of the People's Republic of China

Sponsor:Nanjing Academy of Water Conservancy Sciences

Editor-in-Chief:Li Yun

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ISSN:1009-640X

CN:32-1613/TV

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Publication Period: Bimonthly (1979 initial issiue)

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