Drought prediction is an important non-engineering measure to improve drought prevention and resistance. This paper firstly evaluated the ability of multi-scalar standardized precipitation evapotranspiration index (S_SPEI) to identify drought events in Henan Province. Then a drought prediction model based on particle swarm algorithm optimized extreme learning machine (PSO-ELM) was constructed, which used S_SPEI as model outputs and major drought-causing climate system indices selected by Information Changing Rate and Conditional Mutual Information-Based Input Feature Selection Method (ICR-CMIFS) as model inputs. The applicability of the PSO-ELM model in drought prediction in Henan Province was verified by comparing the drought prediction results of this model with standard extreme learning machine (ELM) and differential evolutionary algorithm optimized extreme learning machine (DE-ELM) models. The results show that the S_SPEI-3 can effectively identify specific drought events in Henan Province and reflect the drought situation in Henan Province accurately in terms of time and space; The main drought-causing climate system indices in Henan Province screened by ICR-CMIFS are the western Pacific paratlantic area index and the NINO index; The PSO-ELM model can predict drought in Henan Province accurately, and the prediction accuracy is better than that of the DE-ELM model and standard ELM model, which has better applicability in drought prediction of Henan Province.

Aiming at the difference of the runoff fluctuation regime after the construction of reservoir, this paper adopted several fluctuation quantification methods to analyze the difference of downstream runoff fluctuation regime after the construction of Three Gorges reservoir from the dispersion, tendency and steepness change degrees on the basis of nearly 70-year long time series of runoff data at Yichang hydrologic station. Compared with the natural runoff regime, the results show that the dispersion degree of runoff decreases (mostly in flood control storage capacity reservation period), the tendency change degree of runoff increases and the steepness reduces (mainly in drawdown period), and totally the fluctuation regime changes intricately.

The research on water level prediction method of Fenshui River control station in Fenshui River basin that improves the prediction accuracy is of great significance to support regional flood control decision-making. The typical historical floods of Fenshuijiang hydrology station from 2012 to 2020 were selected and classified into category Ⅰ and Ⅱ flood based on systematic cluster analysis method, with the maximum 1-day flood volume, peak discharge, peak water level and the proportion of flood initiation duration as cluster indexes. The water level classification and prediction of water level stations were carried out by flow routing and water level and flow relation conversion method. The upper and lower boundaries of the water level and flow relationship of different flood types were constructed, and a classified interval prediction method of flood level was proposed. The results show that the accuracy of flood peak water level prediction for the two types of floods is improved effectively, the width of forecast interval is obviously reduced, and the availability of forecast results is improved.

Based on the GMS software, a numerical model of groundwater flow in the Linfen Basin was established to predict the groundwater level under different driving factor scenarios, and the impact of different driving factors on groundwater level changes was quantified. The results show that only in the precipitation scenarios (dry, normal, and wet), the variation of shallow groundwater is greater than that of confined groundwater. When the precipitation is from 458.8 mm to 568.0 mm, the absolute value of the difference in the annual average water level change rate of the shallow groundwater is 0.11 m; Only under the pressure extraction scenario (extraction volume in 2018 as the benchmark), both shallow groundwater and confined groundwater have great changes. When the pressure extraction increases from 0% to 50%, the absolute value of the annual average water level change rate difference between shallow groundwater and middle-deep confined water is 0.16 m and 0.25 m, respectively; Under the situation of the rising water level of the Fenhe River, only the shallow groundwater on both sides of the river will be affected to a certain extent. The research results can provide a certain scientific basis for the rational utilization of groundwater in the Linfen Basin.

The water level of Poyang Lake is affected by both the Yangtze River mainstream and the Fiver Rivers (namely, Ganjiang River, Fuhe River, Xinjiang River, Raohe River and Xiushui River) in the lake basin. The runoff of the Five Rivers is the main inflow of Poyang Lake. In order to explore the temporal and spatial impact of the Five Rivers on the water level of Poyang Lake, the response of Poyang Lake level variation to the runoff change of the Five Rivers was quantitatively studied by data-driven simulation and sensitivity analysis. Firstly, the lake level prediction model was established by combining PSO-GA algorithm and support vector regression (SVR) technology. The temporal sensitivity of water level of Poyang Lake to runoff change of the Five Rivers was simulated. Then, based on this model, the spatial distribution characteristics of water level response of Poyang Lake to runoff change of the Five Rivers were studied using continuous model simulation. The results show that the most sensitive period that Poyang Lake level response to the runoff change of the Five Rivers is from May to July, especially in May. In terms of spatial distribution, water level in the middle part of Poyang Lake is most sensitive to the runoff change of the Five Rivers. For instance, based on the data in May 2010, when the runoff of the Five Rivers was increased by 40%, water level at Duchang station was averagely increased by 1.16 m within one week; Average water level increased at Xingzi station and Hukou station in the north lake area was 1.15 m and 1.03 m, respectively, and that at both Tangyin station and Kangshan station in the south lake area was 0.97 m. This study clarified the temporal and spatial response characteristics of water level of Poyang Lake to runoff of the Five Rivers, and provides scientific basis for water resources management and water projects optimization in the Poyang Lake basin.

Carrying out quantitative assessment of regional water security is an important basis for water security diagnosis and scientific decision-making. To analyze temporal-spatial characteristics of water security in Gansu Province, an index system of 2 system layers, 6 criteria layers and 25 evaluation indexes was constructed. Based on the combination weighting method of improved AHP and entropy weight method, the weight of each index was calculated. The water security status of 14 cities (states) in Gansu Province in 2010, 2015 and 2020 was comprehensively evaluated by cloud model. The results show that the water security of each city (state) is on the rise in 2010, 2015 and 2020, and it is generally in the basic and relatively security level. The shortage of water resources and flood and drought disasters are the main restrictive factors that affect the water security in Gansu Province. Improving water resources conditions and modern water management level are the important measures to improve the water security in Gansu Province.

The evaluation of carrying capacity of water resources in the middle reaches of the Heihe River is important to promote the efficient use of water resources and sustainable economic development of the region. This paper quantitatively analyzed the dynamic changes of the water resources carrying capacity of the middle reaches of the Heihe River from 2000 to 2020 by selecting 10 evaluation indexes and using the fuzzy comprehensive evaluation model. The results show that the water resources carrying capacity of the region is between 0.3 and 0.5, with the highest value reaching 0.471 in 2020, and the water resources carrying capacities are in a bearable state. In order to improve the rational and efficient use of water resources, the middle reaches of the Heihe River should adjust the water use structure and strengthen the development of water-saving economy and ecological environmental protection.

In order to solve the control problem of rainfall runoff and pollutants in highway service area, SWMM model was used to establish hydrology and water quality model of Tieshan service area. Based on the selection principle of LID measures and the site conditions of Tieshan service area, the control efficiency of rainfall runoff and pollutants in the service area were studied under four schemes of without LID measures, combination of infiltration pavement and green roof, combination of sunken lawn and green roof, and combination of permeable pavement and sunken lawn under different rainfall return periods. The results show that the three combined LID measures can effectively reduce the rainfall runoff, peak runoff, pollutant concentration and total pollutant load in the service area, among which the LID combined measure scheme of permeable pavement and sunken lawn has the best effect on pollution interception and emission reduction. In addition, the LID measures are more effective in controlling rainfall runoff and pollutants when the rainfall intensity is low than that is high.

The ecological and economic value of water resources is the unity of economic value, social value and ecological environmental value. It is of great significance to analyze the change rule of its value for rationally optimizing the allocation of water resources, promoting the sustainable development of the ecological and economic system of water resources. The emergy theory analysis method was used to calculate the ecological and economic value of water resources in Zhengzhou City from 2009 to 2020. Its time evolution law and influencing factors were discussed, and its future development trend was analyzed by R/S analysis method. The results show that there is a growing trend for water ecological economic value in Zhengzhou City on the whole. The value change is mainly affected by GDP, per capita disposable income, sewage wastewater emissions and other factors. The results show that the future trend in the past time series characteristics were positively related, namely, water ecological economic value in Zhengzhou City still showed a trend of growth in the future.

In order to reveal the pollution characteristics of heavy metals in surface sediments in the upper reaches of the Zhanghe River, the chemical fractions and contents of Cr, As, Cd and Pb in 32 samples were determined. The potential ecological risks were assessed by rations of secondary phase and primary phase, and risk assessment code method. The correlation analysis was used to analyze the sources of heavy metals. The results show that the average contents of heavy metals Cr, As, Cd and Pb are 91.51±24.30, 9.81±3.05, 0.12±0.05, 18.30±5.43 mg/kg, respectively, and only the average contents of Cd do not exceed the background value. Only the content of Cd does not exceed the background value. The exchangeable fraction of Cd is larger than Cr, As, and Pb, and its biochemical activity is relatively high. The potential risks of heavy metals are sorted as Cd>Pb>As>Cr, and the risks are mainly concentrated in the source of Zhuozhang River and the west headwater of Qingzhang River. These four heavy metals mainly come from mineral exploitation, and mining activities contribute to the content and potential risks of heavy metals.

Huaxi Reservoir is a typical karst mountain reservoir and an important water source in Guiyang City. In order to find out the distribution of heavy metals in the sediment of Huaxi Reservoir, a total of 21 sets of sediment samples were collected from two cross sections. The content of Cr, Cu, Zn, As, Cd, Pb and other heavy metal elements were determined by inductively coupled plasma mass spectrometer (ICP-MS). Their distribution characteristics and content levels on the cross section were analyzed. The potential ecological risk assessment method and geo accumulation assessment method were used to evaluate the pollution risk, and systematically analyze the degree of heavy metal pollution in two different sections of the reservoir. The results show that the content of heavy metals in the section of inlet reservoir is low and lower than the background value, and its concentration sequence is Zn>Cr>Cu>As>Pb>Cd; The heavy metal content has a law of decreasing with the increase of the offshore distance, the main reason is caused by the influence of surrounding agricultural activities; The content of heavy metals in open sections is relatively low, and the concentration sequence is Zn>Cr>Cu>Pb>As>Cd; The heavy metal content increases from the left bank to the right bank, which is mainly related to river velocity and sediment particle size. The heavy metal pollution in the sediment of the reservoir is light pollution, and the pollution degree of the section near the reservoir is right bank>left bank>river center, and the pollution degree of each heavy metal in the open section gradually increases from left bank to right bank.

This paper selected 6 typical cape-bay sandy beaches in Wenzhou area to sort out the natural environment. The parabolic plane morphology model (MEPBAY) was used to compare the relative positions of the static simulated shoreline with the recent actual shoreline. The advancing and retreating trend of the coastline of the shaped sandy coast was analyzed. The current stability of the coastal beaches of Cape Bay in Wenzhou area was discussed. The results show that the coastline is in a stable state as a whole, and the profile of sandy beaches is mainly divided into four types: concave downward, upward convex, slope, and slope + upward convex combination. The characteristics of the interannual erosion and deposition changes of the profile are mainly divided into three modes: the upward erosion and the downward siltation, the overall erosion type and the basic stable type.

Taking Jinghe River Basin in Gansu Province as the main research object, the Jinghe River trunk canal irrigation area in the upper reaches of Jinghe River was selected as a typical experimental irrigation area. The irrigation return water, farmland water content and crop growth trend of Jinghe River trunk canal irrigation area were monitored. The water consumption of Jinghe River trunk canal irrigation area was tested by the combination of diversion and drainage difference method and multi-level soil water balance model (VSMB model). According to the monitoring experiment, the total water diversion volume of Jinghe River main canal irrigation area in 2018 is 20.76 million m³, and the total water return volume is 5.23 million m³. The water consumption coefficient of Jinghe River main canal irrigation area is 0.56 by using the diversion and drainage difference method. The total annual water diversion of typical plots in Gannong experimental field is 1 901 m³, and there is no retreating water on the surface. The water consumption coefficient obtained by diversion and discharge difference method is 0.75, and the water consumption coefficient obtained by VSMB model is 0.71. The research results provide reference for the study of water consumption coefficient of other agricultural irrigation areas in Jinghe area, and have certain guiding significance for irrigation area planning and design and high-efficiency agricultural irrigation pilot work.

In order to accurately describe the water environment quality of Shiyang River Basin and clarify the main pollution factors of water quality, according to the analysis results of water quality data of typical sections of Shiyang River Basin in Gansu Province, five pollution factors including dissolved oxygen, chemical oxygen demand, ammonia nitrogen, total phosphorus and fluoride were selected as water quality evaluation indexes. A combined weighting comprehensive evaluation model based on CM-AHP and entropy weight method was established to study the main pollution factors of Shiyang River Basin. The results show that the combined weight of total phosphorus and ammonia nitrogen pollution accounted for the largest proportion, reached 0.438 and 0.296, respectively, which were the main pollution factors of Shiyang River. The water quality of Shiyang River Basin gradually deteriorated from the upstream to the middle and lower reaches.

In order to solve the problem of interval flow inversion of cascade hydropower stations, taking the cascade hydropower stations in the middle and lower reaches of the Dadu River basin as an example, the characteristic curve correction of the six reservoirs in the basin was carried out. In order to accurately calculate the inflow and outflow of each reservoir by correcting each characteristic curve, and make the flow inversion rate of each interval meet the requirements, four correction methods of characteristic curve correction methods were proposed with the goal of minimizing the flow inversion rate, which includes single-point discrete optimization, multi-point discrete optimization, curve cluster overall translation optimization, and distinguishing different water head/water level translation optimization. The simulation calculation shows that although each curve correction method has certain effect, the distinguishing different water head/water level translation optimization method has the best effect. After using this method to correct the characteristic curve, the interval flow inversion rates of PuSheng and GongTong decreased from 53% and 77.96% to 13.93% and 4.37%, respectively. Although the flow inversion rates in the remaining intervals has slightly increased after correction, they are all within a reasonable range. It can be seen that the curve correction method effectively reduces the inversion rate of interval flow and improves the consistency of runoff series, which can provide a data basis for the accurate water regulation of cascade hydropower stations in the Dadu River basin.

Water environment safety has always been an important issue that plagues the healthy development of country's social economy. Low-impact development technologies have good resilience in dealing with water environment safety issues. Taking Cangzhou China-Europe Green Industrial Park as the research object, the rainstorm flood model and the rainwater resource utilization benefit model were established. The study found that green roofs have an obvious control effect on ground runoff. The reduction rate and control rate of the total runoff are 56.31% and 68.32%, respectively, and the peak flow reduction rate is 48.58%. The control rate for pollutants of TP, TN, SS and COD is 72.92%, 74.82%, 74.44% and 73.89%, respectively. However, with the increase of rainfall intensity, the runoff control rate and the pollutant concentration control rate decreased, showing a significant negative correlation between the fourth and fifth power functions. After calculation, green roof can produce better economic and environmental benefits.

In recent years, rainstorm and flood disasters occur frequently in the basin. Accurate and reliable flood forecasting is an important measure to effectively prevent and resist mountain torrents. Taking Lushui basin as the research area, this paper constructed the HSPF semi-distributed model. Choosing the representative floods in the flood data of the basin from 2013 to 2020, the calibration and verification of the model parameters were carried out. The accuracy of flood simulation was evaluated by using indexes of certainty coefficient and relative error. The results show that the model has a good performance in the field flood simulation of Lushui basin. The qualified rates of peak time and peak discharge of 15 flood simulations are 100.0% and 80.0%, respectively, the qualified rates of flood volume and runoff depth are 93.3%, and the average value of certainty coefficient is 0.80. The overall prediction accuracy reaches class B, indicating that the HSPF flood prediction model has good applicability in Lushui basin. The research results can provide basis for flood forecasting in this area.

Based on the climatic conditions and flood characteristics of the Puhe River Basin, this paper used Tank model to simulate 10 rainstorm flood processes in the basin from 2019 to 2020, constructed a conceptual rainstorm flood meteorological risk early warning model suitable for the basin, and carried out simulation and accuracy evaluation. The results show that the improved water tank model can intuitively simulate the water level change process curve of Shijiao hydrological station under different time scales and different basic water levels, reduce the uncertainty of area rainfall threshold, and the prediction accuracy is class B; Meteorological risk warning is issued level by level according to the simulation results, and the skill score and hit rate are 100%; The average early warning release time is more than 3 hours in advance, which can be substituted into the predicted precipitation to further extend the flood forecast period.

Pumped storage power station is the most mature large-scale energy storage tool in power systems. Because of its flexible peak and frequency modulation performance, it plays an important role in the novel power systems with new energy as the main body. The selection of upper and lower reservoirs is the key factor to determine its energy storage capacity and investment benefit in the process of site selection of pumped storage power station. However, the traditional site selection method of manual site investigation has the problems of heavy workload, low efficiency and easy leakage. In this paper, a method for site selection of upper and lower reservoirs of pumped storage power station based on satellite remote sensing terrain data was proposed, and experimental verification was carried out by Jinyun pumped storage power station in Zhejiang Province. The results show that the possible upper and lower reservoir construction areas within the target area can be efficiently screened out by using satellite remote sensing terrain data and computational intelligence techniques, which greatly improves the efficiency of site selection and shows the great application potential of satellite remote sensing in site selection of pumped storage power station.

In the design scheme of asphalt concrete core rockfill dam, the axis of diaphragm of dam foundation and asphalt concrete core wall is overlapped. However, due to construction errors and other reasons, the axis of diaphragm of dam foundation and asphalt concrete core wall may not be completely overlapped. Based on the finite element analysis method, the stress behavior of diaphragm of dam foundation and asphalt concrete core wall under different offsets was studied. The results show that under the superposition of axes, the local tensile stress of the diaphragm of dam foundation is in a state of no or small in the construction period and operation period, which has little influence on the whole. The minor offset of the axis of the diaphragm of dam foundation to the downstream will have a certain adverse effect on the stress of the diaphragm of dam foundation during operation. The main performance is that the local tensile stress of the downstream face of the diaphragm of dam foundation increases, and there is stress concentration. The local tensile stress increases by 3.6 times compared with that without offset. The concrete base of the asphalt concrete core wall can be slightly extended to the downstream according to the offset of the diaphragm of dam foundation, which can reduce the local tensile stress of the downstream surface of the diaphragm of dam foundation by 59.3 % and weaken the stress concentration, so as to improve the stress state of the diaphragm of dam foundation. The finite element simulation analysis can provide support for safety evaluation and selection of engineering treatment measures under eccentric condition of diaphram of dam foundation.

Due to the frequent storage and discharge cycle of the reservoir, the cushion of the face rockfill dam of pumped storage power station should have good drainage performance, but when the face slab appears cracks, the cushion with low fine particle content may have the problem of seepage stability. Taking the concrete face rockfill dam of a pumped storage power station as an example, the inverted filtration test and seepage calculation and analysis were carried out, focusing on the filter protection mechanism of cushion material and transition material. The allowable crack width of the face slab was determined according to the damage slope of cushion material. The results show that after properly optimizing the fine particle content of cushion and transition material, the requirements of inverted filtration criterion can be met, and the allowable crack width of the panel is increased by 30% on the premise of ensuring the seepage stability of cushion.

Aiming at the problems of high economic cost and difficult construction of the anti-seepage scheme designed for the dam site area of the concrete face dam of the lower reservoir of a pumped storage power station, a three-dimensional finite element model was established according to the actual engineering situation of the lower reservoir site. Firstly, the distribution of seepage field and the factors such as seepage gradient and seepage flow in each part of the reservoir area under the design anti-seepage scheme were calculated. Then the effects of different curtain depth and the change of curtain length of left and right dam abutment on seepage gradient and seepage flow were analyzed. Finally, the optimization suggestions for the design anti-seepage scheme were put forward. The results show that the curtain depth of the dam site area can be shortened to 3 Lu line, and the curtain length of the dam abutment on the left and right banks can be shortened by about 10 m. Therefore, the project cost can be reduced and the construction progress can be accelerated on the basis that the key parts of the dam site area can meet the seepage stability and the total seepage flow can be effectively controlled.

Aiming at the problem that many measured thermometer data are not effectively used in the previous prediction of crack opening and closing time series data, and there are multiple correlations between their variables, considering the advantages of principal component analysis (PCA) in dealing with multidimensional data and gate recurrent unit (GRU) neural network in dealing with complex time series data, this paper constructed the PCA-PSO-GRU combined prediction model. Taking the monitoring data of the opening and closing of the left inducing joint of a concrete gravity arch dam as a sample, the principal components of the input variables were extracted to reduce the dimension of the input data. And then the model training and multi-step prediction were carried out. The mean absolute error and root mean square error were used to evaluate the prediction accuracy of the model. The prediction results were compared with PSOGRU, PCA-PSO-BP and the traditional statistical regression models. The results show that the PCA-PSO-GRU combined prediction model has higher accuracy in the prediction of inducing joint time series data, which can provide guidance for the evaluation of opening and closing degree of dam inducing joints.

Aiming at the low natural moisture content of natural wide graded gravel anti-seepage soil material in 300 m level high core wall rockfill dam, field contrast test between the process of “belt conveyor filling water + stacker heap + bin stuffy material” and the process of “layered paving + pipe network water + bin stuffy material” was carried out to verify the rationality and feasibility of the relevant filling water process. The test results show that the combination process of belt conveyor with water is superior to the pipe network stratified water process, mainly manifested that the belt conveyor automatic water system can achieve real-time, efficient and accurate automatic water filling soil; After water replenishment, the soil material is transported by the belt and piled by the stacker, which can realize automatic and uniform piling. After adding water to soil material, the moisture content inside the soil material is basically stable during 3-4 days of smother, and the time required for smother is short. This paper also put forward the improvement measures of water filling process of belt conveyor. The improved process of "water filling of belt conveyor + stoker + silo boring" can provide reference for soil water content adjustment of similar earth-rock dam.

Aiming at the problem of failure path analysis of high arch dams, the current numerical simulation methods still do not take into account the tensile and compressive damage characteristics of dam concrete. Therefore, the concrete damaged plasticity (CDP) constitutive model was used to analyze the damage and failure characteristics of the Laxiwa arch dam under the conditions of static overload, sudden temperature drop and maximum credible earthquake. The results show that the dam body mainly suffers from the tensile failure of concrete at the dam heel and bank slope dam foundation under overload conditions, and loses its bearing capacity after the damage penetration zone is formed; Under the condition of sudden temperature drop, the concrete of the dam body may cause tensile damage in the surface hole and the 1/4 arch dam crest, arch end and dam heel area; While under the earthquake condition, the surface hole near the crown beam of the dam crest downstream surface is mainly used for tensile damage. Tensile failure is dominant, and a horizontal band-shaped failure area is gradually formed and the bearing capacity is lost. The research results clarified the possible damage characteristics and failure paths of the Laxiwa arch dam, and provided a reference for determining the key parts of the Laxiwa arch dam structural safety monitoring analysis.

Investigating the effect of spacing on the effect of staggered-slip permeable spur dike on flow mitigation can provide a theoretical basis for the design of modern shore protection projects. The CCHE2D software was used to conduct a two-dimensional numerical simulation study of the solid flume model in the Xinqiman section of the Tarim River. And then the effect of different spacing on the water surface line, flow velocity and bed shear stress distribution in the upstream permeable spur dike area under the action of staggered-slab permeable spur dike was analyzed. When the relative dam length ratio is 0.21, and the inflow and dam length remain unchanged, the larger the spacing, the better the uniformity of flow and velocity behind the upstream permeable spur dike, and the lower the value of water level and shear stress in the riverbed. When the spacing is 5 times the effective dam length, the flow velocity, water level and riverbed shear stress behind the upstream permeable spur dike tend to be stable. The results of the study can improve the theory of flow mitigation effect in the action area of inserted permeable spur dike.

Aiming at the complicated law of specific energy along stepped chute and the low accuracy and limited application scope of current calculation method of water surface profile, a reliable method of calculating water surface profile was proposed. Based on hydraulic model test, this paper introduced the relative specific energy and made dimensional analysis. Then the dimensionless relative specific energy was systematically studied qualitatively and quantitatively. The results show that the dimensionless relative specific energy is related to the relative critical water depth, spillway slope and dimensionless position. The dimensionless relative specific energy has a good linear correlation along the stepped spillway. Based on the quantitative research results, the empirical formula of dimensionless relative specific energy calculation was given, and a new method of water surface profile calculation was obtained. The analysis of numerical example shows that the calculation method of water surface profile has high accuracy and wide application range, which can provide theoretical reference and technical support for the design of stepped chute.

In order to investigate the influence of the bottom dip angle of contraction section of the dustpan-shaped inlet on the hydraulic performance of the passage, the physical model and hydrodynamic model of the inlet structure of the dustpan-shaped inlet were established. The Reynolds N-S equation and RNG κ-ε turbulence model were adopted to simulate the flow field of the passage with 5 different underside inclinations in the inlet contraction section. The results show that the bottom dip angle increases has a great influence on the velocity distribution of the inlet contraction section and the throat of the winnowed dustpan-shaped inlet passage, and the scheme of the bottom dip angle increases the density of the srteamline distribution and the curvature of the throat, with the increase of flow velocity, the hydraulic loss of the passage is large, and the velocity distribution uniformity of the outlet section of the passage is low; The scheme with small bottom dip angle makes the streamline distribution smooth and the throat streamline curvature becomes slow, the velocity decreases, the hydraulic loss of the passage reduces, and the velocity distribution uniformity of the outlet section of the passage increases; The magnitude of the inclination of the bottom surface of the intake contraction section has no obvious influence on the weighted average angle of the flow velocity of the outlet section of the passage. Hydraulic performance of passage with different bottom dip angles was analyzed. When the bottom dip angle of the inlet contraction section of the dustpan-shaped inlet passage is less than 3°, the water flow in the inlet passage is smooth, the hydraulic loss is small, and the flow pattern at the outlet of the passage meets the water inlet conditions of the pump impeller chamber.

In view of a flood discharge hole of a hydropower station, two types of flip buckets were proposed. The experimental study was carried out with the arc bevel and the new upper and lower composite flip bucket for hydraulic model in flood discharge hole. The parameters of two types of flip buckets such as shape of the water jets, jet trajectory length and the depth of downstream scour hole were compared and analyzed. The test results show that the new type of flip bucket divides the water flow into two parts, forming two upper and lower parallel floors water jets, which fall into the river channel in a parabolic shape, and the width of the two layers of water jets is controlled within the range of the river channel. The trajectory water jets have a stable flow state and are fully diffused in space and plane. Compared with the arc bevel flip bucket, the scour depth of downstream riverbed, the surge height, and the bank flow velocity have all been reduced to a certain extent. Finally, the Ansys Fluent software was used to carry out numerical simulation verification of the designed new flip bucket, and the shape of the tongue, jet trajectory length, turbulent kinetic energy and turbulent kinetic energy dissipation rate under each working condition were obtained. Comparing with the results of numerical calculation and model test, the flow patterns of the two are consistent, and the results of the trajectory length and width of the water jets are basically consistent, which verifies the reliability of the numerical simulation, and provides convenience and technical support for research of ski-jump energy dissipation.

For the intersection problem of the outlet pipe shared by adjacent units of pumping station, three schemes for the intersection of the outlet pipe of the adjacent units was proposed based on the original scheme of the pump station. The influence of different intersection forms of the outlet pipe on the hydraulic performance of the pump station pipe was investigated with numerical simulation. The results show that the hydraulic losses of plan 2 and 3 were reduced by about 50% compared to the original plan. The flow field distribution before the junction point of the outlet pipes was improved obviously by the three optimization schemes. In the middle flow surface, the pressure and streamline distribution characteristics of plan 3 were better. Compared with the original scheme, plan 1 and plan 2 can improve the flow field of unit 2 and the vortex and secondary flow were reduced before the intersection point. After the intersection point, the flow field distribution of plan 2 was smoother and the hydraulic performance was better. Both the hydraulic performance of each scheme and construction were considered, plan 3 was finally determined as the optimal scheme.

Aiming at the problem of low economic benefits of pump stations caused by unreasonable dispatching, this paper took the pump stations with multiple piping systems as the research object. Considering the impact of peak-valley electricity price, a pump station daily economic optimization model was established by taking the minimum daily operating cost as the goal. The secondary pump station of the connected river reservoir project was taken as a study case to compare constant speed throttling regulation and frequency conversion regulation, which bases on the improved genetic algorithm and dynamic programming method of combined variation. The results show that the improved genetic algorithm is suitable for optimal dispatching of pumping station. At the same time, it is found that when the actual operating points of the pump unit far from the design operating point, adopting frequency conversion regulation has higher economic benefit.

Aiming at the problems of difficult modeling, low prediction accuracy and poor adaptability of the operation trend prediction of cascade pumping station units under the process of multi-factor participation, this study took Yanhuanding Yellow River Project in Ningxia as the research object, introduced the time series analysis method, and put forward the operation trend prediction method of pumping station units based on ARIMA and SVM combination model. The energy consumption and average load in the operation technical parameters of the unit were selected as the test samples. The ARIMA model was used to linearly fit the processed data, and the SVM model was used to predict the residual error to compensate for the nonlinear change in the operation of the unit. The prediction results of the combination model were obtained by combining the two prediction results. The results show that the optimal models are ARIMA (1, 1, 3) and ARIMA (2, 1, 1), and the optimal parameters of SVM model are c=38, g=0.06 and c=68, g=0.18, respectively. The goodness of fit of the combined model for the test samples were 0.999 2 and 0.998 4, R_RMSE were 1.67×10^-5 and 3.9×10^-8, the M_MAPE were 0.036 1 % and 0.074 7 %, indicating that the combined model has high accuracy and good effect in predicting the operation trend of pumping stations. ARIMA-SVM combination model can provide a theoretical basis for the optimization and upgrading of pumping station unit operation condition monitoring system.

Accident pump-stopping water hammer is a technical problem that needs to be highly valued in long-distance pressurized water diversion projects. This paper carried out calculation and analysis of hydraulic transition process on the Oujiang River Diversion Project. The loss of power accident of four pumps under maximum lift was taken as control condition, and the loss of power accident of single pump was taken as verification conditions. The optimization of pump outlet valve closing law was taken as the main water hammer protection measure. The research shows that when the butterfly valve at the outlet of the pump refuses to operate, the pressure and flow in the pipeline fluctuate more violently than that of the single pump during pump trip accident, and the reverse speed of the pump does not meet the specification requirements. By adopting the two-stage broken line closing law of the pump outlet butterfly valve, a better water hammer protection effect can be obtained.

When the pipeline truck moves smoothly, the velocity distribution characteristics of the water flow in the annular gap are related to the interaction between the pipeline truck and the water flow, which will also affect the motion characteristics of the pipeline truck and the hydraulic characteristics in the pipeline. This paper studied the overall and local distribution characteristics of the water flow velocity in the annular gap when the pipeline car moves smoothly by means of physical experiments and theoretical analysis. The relationship between the distribution characteristics of the water flow velocity in the annular gap of the pipeline car with different diameters and the transmission efficiency were compared. The results show that when the pipeline car moves smoothly, the velocity at the inlet section of the annulus is the largest, followed by the middle section of the car, and the velocity at the rear section of the car is the smallest; The flow velocity near the wall of the pipeline truck changes greatly along the way, and the flow velocity near the pipe wall changes less along the process; The distribution of the water flow velocity in the annular gap of the pipeline car with different diameters affects the transportation efficiency of the pipeline car. When the ratio of the water flow velocity in the annular gap to the water flow velocity in the pipeline is close to 1, the transportation efficiency of the pipeline car is the highest.

For underground powerhouse in high geostress area, the excavation of the lower powerhouse cavern after the completion of the pouring of the rock-anchored crane beam may have an adverse impact on the crane beam. Aiming at this problem, three-dimensional elastoplastic finite element method was used to analyze the stress and deformation, the stress of the anchor and the stability of the crane beam of an underground powerhouse during construction and operation period. The results show that in the high geostress field, the rock-anchored crane beam will have large deformation, and the joint surface between the beam and the surrounding rock will have large tensile stress. After the crane beam is poured, the stress and deformation of the beam will increase greatly in three stages. As the excavated part is far away from the beam, the stress and deformation of the beam will become gentle, and the safety factor of the joint surface between the beam and the wall will be large, which can provide a reference for the crane beam pouring and cavern construction in similar projects.

Columns are commonly used in water conservancy project to support the upper structure. In order to ensure the stability of the upper structure, it is necessary to monitor the deformation of the column to ensure that the inclination angle of the column is within the allowable range. The non-contact measurement and high-precision point cloud data acquisition was carried out by the total station scanner used waveform digital ranging technology. During the acquisition process, the three-dimensional coordinates of each observation station were calculated by the rear intersection method, and the observation data was unified into a coordinate system. Data registration avoided the transmission of observation errors. This paper proposed a method for calculating the tilt deformation of the column using the point cloud. After collecting the two phases of the point cloud data, the deformation was calculated based on the true pair of points, and the point and surface optimization algorithm was used to reduce the error, and the tilt angle of the column was calculated. Finally, a simulation test of the tilted deformation of the column was designed to verify the accuracy of the deformation calculation method. The test results show that the actual inclination angle is 0°16'49", the calculated inclination angle is 0°16'57", the algorithm error is less than 20', which meets the requirement of deformation monitoring in high-rise structure. Therefore, the deformation calculation method can be applied to the field of column tilt deformation monitoring.

Due to the randomness of concrete carbonation process, the results obtained by the existing carbonation depth prediction models are difficult to characterize the actual carbonation status of in-service concrete structures. Therefore, combining the existing stochastic carbonization model with the actual measurement information of the carbonization depth of in-service concrete structures, a calculation method of a priori distribution hyper-parameters was given when the mean and variance of carbonized population samples were unknown. A Bayesian random model for the carbonation depth of in-service concrete structures was established. Taking the measured concrete carbonation depth of spillway pier and other structures of Yanshan Reservoir as an engineering example, the results show that the Bayesian random model can better represent the actual carbonation condition of in-service concrete structure.

In order to explore the relationship between macro and micro characteristics of hybrid fiber reinforced concrete under freeze-thaw cycles, rapid freeze-thaw cycle tests were carried out with freeze-thaw cycles and fiber volume content as variables. The test results show that under different freeze-thaw cycles, the compressive strength has a positive correlation with air content, bubble spacing coefficient and average chord length of bubbles, and a negative correlation with specific surface area of pores, while the freeze-thaw damage and pore parameters have an opposite law, and they all change approximately linearly; The larger the freeze-thaw cycles, the lower the compressive strength, the greater the freeze-thaw damage, the greater the air content, the bubble spacing coefficient and the average chord length of bubbles, and the smaller the specific surface area of pores; The incorporation of hybrid fibers optimizes the pore structure and improves the frost resistance.

In order to study the deformation and internal force of concrete lining structure of expansive soil trapezoidal channel in northern Xinjiang, indoor test and numerical simulation were used to calculate expansive deformation of foundation soil. Based on the beam theory of elastic foundation, a mechanical model was established to calculate the deformation and internal force of concrete lining slab. The deformation and internal force of concrete lining slabs were calculated and analyzed after the operation of the channel with the initial moisture content of the foundation soil being 6%, 9%, 12% and 15%. The results show that the deformation and internal force of the concrete lining plate increase with the decrease of the initial moisture content of the foundation soil. When the moisture content of the foundation soil is 6%, the maximum expansive deformation of the channel floor and slope plate can reach 3.48 cm and 3.94 cm. When the initial water content is constant, the expansion reaction force is the largest at the foot of the slope, and the displacement and bending moment are the largest at the middle of the bottom plate. The displacement of channel slope plate is the largest at one third of the slope foot, and the bending moment is the largest at one sixth of the slope foot. Finally, according to the research results, two engineering measures of "anti-seepage and moisturizing" were proposed.

In order to study the applicability of recycled aggregate in hydraulic asphalt concrete, the mix proportion test of recycled aggregate hydraulic asphalt concrete was carried out, and its mix proportion parameters were determined through uniaxial compression, splitting test and permeability (porosity). The asphalt aggregate ratio is 7.0%, the grading index is 0.37, the filler content is 13%, and the replacement rate of recycled aggregate is 50%. The recycled aggregate was modified with modifiers of different concentrations. The water absorption, apparent density, crushing index and adhesion of the recycled aggregate were analyzed to determine the modifier concentration that meets the test requirements. The modifier concentration in this test is 10% of water glass and 12% of silane coupling agent. Based on the above research, the applicability of recycled aggregate in hydraulic asphalt concrete was studied through water stability coefficient, thermal stability coefficient and permeability coefficient. The results show that the application of recycled aggregate in hydraulic asphalt concrete can meet the requirements of the specification, which can provide a reference for the popularization and application of recycled aggregate in hydraulic asphalt concrete.

In order to study the uniaxial tensile behavior of autoclaved aerated concrete blocks (AACB) in static state, the uniaxial tensile test of AACB with different densities was carried out. The tensile failure characteristics and failure mechanism of AACB were analyzed. The change rules of its tensile strength and elastic modulus under different densities were discussed, as well as the relevant formulas of the relationship between uniaxial tensile strength and porosity, compressive strength and splitting tensile strength. The experimental results show that the tensile yield strength and elastic modulus of AACB increase with the increase of density, but the tensile yield strain decreases gradually. The macroscopic failure of AACB under uniaxial tension is mainly controlled by the tensile damage mechanism of the material. It shows obvious brittle failure characteristics. Based on the ideal prediction model of porous materials and the regression analysis of test results, the semi-empirical formula and correction coefficient of AACB uniaxial tensile strength and porosity under the test conditions were fitted. The conversion relationship between AACB tensile strength and its compressive strength and splitting tensile strength was proposed.

In view of the problem that the compaction coefficient of cement improved silty fine sand road in Gobi area is difficult to meet the standard after the completion of rolling inspection as an engineering material, after comprehensive analysis, it is found that the timeliness of cement improved silty fine sand is not considered in on-site construction and inspection. Through the design of compaction test and unconfined compression test of cement improved silty fine sand under different delay time, the influence of delay time on the compaction characteristics and strength characteristics of cement modified silty fine sand was analyzed. Considering the strength change of Subgrade in seasonally frozen area after freeze-thaw cycle, the freeze-thaw cycle test of cement modified silty fine sand under the influence of delay time was designed. The results show that with the increase of delay time, the maximum dry density of cement modified silty fine sand first increases and then decreases, and the optimal water content first increases, then tends to be flat and then increases; The saturated 7 d unconfined compressive strength and the strength after freeze-thaw cycle decreased gradually with the increase of delay time; The structure formed by cement hydration inside admixture has been destroyed after being rolled and formed, reducing the cement effectiveness.

The rise and fall of reservoir water level will make the water storage environment of bank slope rocks different at different heights and water levels, and the types of water rock interaction are also different. Based on this, the deterioration test of rock mechanical properties of bank slope in water rock interaction zoning was carried out. The results show that the compressive and tensile strength of rock samples decrease with the increase of test cycle, showing a deterioration trend from fast to slow. With the advance of water rock interaction cycle, the shear failure characteristics become more and more obvious in the compressive and tensile tests of rock samples; The microstructure of rock sample gradually transits from dense to loose, porous and multi crack structure. Under different water rock interaction, the mechanical properties and microstructure deterioration degree of rock samples ranks thermal wet cycle > dry wet cycle > long-term immersion. The results can provide ideas for the long-term stability analysis of bank slope based on water rock interaction zoning.

Anti-dip layered rock slope is a common type of slope in hydropower engineering. Its stability is controlled by slope geometry, rock characteristics and structural plane properties. To reveal the influence of multiple factors on the stability of such slopes, taking the safety factor and displacement as dependent variables, the significance of six main factors, namely slope angle, slope height, rock inclination angle, rock thickness, rock quality and structural plane quality, was studied based on the approaches of discrete element modelling and orthogonal test design. Moreover, the deformation and failure laws of typical modes for anti-dip slopes were analyzed. The study can provide a reference for the optimal design of anti-dip layered rock slopes.

Geostress field plays an important role in the stability of tunnel surrounding rock. Based on the in-situ stress results and geological conditions in the cracked area of the secondary lining concrete of the Qinling water conveyance tunnel from Hanjiang-to-Weihe, three-dimensional hydraulic fracturing method was used to analyze the in-situ stress of the surrounding rock in Qinling tunnel. The results show that the maximum principal stress on the cross section of the horizontal hole is 16.3-37.9 MPa and the minimum principal stress on the cross section is 2.4-9.1 MPa in the horizontal drilling depth range of 9.2-26.6 m. In the vertical drilling depth range of 3.8-20.7 m, the maximum horizontal principal stress is mainly 21.5-30.5 MPa, the azimuth average is N57°E, and the minimum horizontal principal stress is mainly 12.7-16.5 MPa. The maximum and minimum and the spatial maximum principal stress are 24.3 MPa, 14.4 MPa and 24.6 MPa respectively, which are nearly horizontal distribution. The stress field of surrounding rock at the test site of tunnel rock mass is mainly horizontal stress and the rock mass stress is classified as "high in-situ stress".

In the long service process of the deep excavated expansive soil channel slope, the real-time identification of the service behavior of the channel slope by means of displacement monitoring index is an important means to ensure the safe operation of the channel slope. Therefore, it is of great significance to formulate reasonable monitoring indexes for the safety of canal slope engineering. The POT model was presented in this paper. On the basis of introduction of 2 σ criteria and chauvenet principles, the threshold T and the corresponding relation between monitoring index was established. Through the best solution to satisfy the relationship between threshold, a canal slope displacement monitoring index for improved POT model was established to apply to the Taocha section of South-to-North Water Transfer Project of deep excavation expansion earth canal in slope engineering. Compared with the traditional POT model, the results show that the improved POT model based on 2σ -chauvenet criterion can effectively avoid subjectivity and random error, and it has higher calculation accuracy. The proposed displacement monitoring index is more safety, which has stronger guiding significance to prevent the risk of canal slope and ensure the safe long-term operation of canal slope.

In view of the difference between the performance of cemented gravel soil under low normal stress and high normal stress, based on the Mohr-Coulomb strength criterion, according to the Mohr-Coulomb strength line of cemented gravel soil before and after yield stress, a polygonal line strength criterion of cemented gravel soil was proposed. The relationship between strength criterion parameters and uniaxial compressive strength and uniaxial tensile strength was deduced. Uniaxial compression test and direct tensile test were carried out to calculate the strength criterion parameters and compare with the strength criterion parameters obtained by triaxial compression test. The results show that the error range between the calculated value and the experimental value is reasonable. The polygonal line strength criterion is suitable for cemented gravel soil.

Aiming at the problem that the reliability calculation results of embankment slope stability are not accurate due to the fact that the correlation between variables cannot be considered in two-dimensional independent distribution, based on 171 sets of test data of the shear strength of the Yangtze River embankment shoreline soil, Copula function was used to study the correlation between the shear strength parameters of the Yangtze River embankment shoreline soil. The AIC and BIC criteria were used to identify the optimal edge distribution and Copula function, and a two-dimensional joint distribution model was constructed. The influence of data volume on the identification of correlation structure between parameters was analyzed. The results show that the two-dimensional joint distribution model based on Copula function can accurately characterize the correlation between soil parameters of the Yangtze River embankment shoreline; When the data volume is more than 24 groups, AIC and BIC criteria can accurately identify the optimal Copula function, which provides a reference for the reliability calculation of embankment slope and the construction of Copula function model.

This study analyzed the mechanism of groundwater gushing from Quaternary boreholes at Aishan section of the lower reaches of the Yellow River in autumn floods. Groundwater level analysis, meteorological analysis, runoff analysis of the Yellow River, combined with isotopic analysis of groundwater and surface water samples were used. The results show that the average groundwater level was increased more than 3 m, which reduced the groundwater runoff. The increase of groundwater level was the basic factor of groundwater gusher. Continuous high water level of the Yellow River and the intensive water replenishment of the Yellow River to groundwater directly led to the groundwater gushing. The warning groundwater level of wells near Aishan section of the lower reaches of the Yellow River was 39.5 m within the 500 m outside the dike. This paper provides a basic understanding for preventing groundwater gushing from wells outside the levee of the Yellow River, and it is helpful for the protection of the levee of the Yellow River.

To avoid flow surface morphology change caused by wear and cavitation erosion of turbine movable guide vane and the unit efficiency decrease, ultrasonic vibration cavitation machine, high-speed jet of gaza's grinding apparatus and circle grinding apparatus were used to carry out cavitation erosion test for epoxy mortar, mortar composite resin and polyurethane and movable guide vane base material of ^#45 steel. Based on the test results, the cavitation erosion resistance and impact wear resistance of different materials were analyzed, and the service life of materials under strong cavitation erosion was predicted. The influence of flow rate, attack angle and sand content on material wear was studied, and the prediction model of material wear was established. The results show that the corrosion resistance of the materials is as follows: polyurethane > composite resin mortar > epoxy mortar; The abrasion loss of material has a linear or exponential relationship with the increase of velocity. The relationship between wear and sand content is linear. When the attack angle increases gradually, the impact wear first reaches the peak value and then decreases gradually. The critical attack angle of different materials is different.

For the 1# bulb tubular unit of Baisha Hydropower Station, the prestress vanishment of the rotor bracket and hot sleeve of the spindle could results the scratching of the generator and the uneven air gap between stater and rotor, which generates the excessive unilateral magnetic pull. This problem may lead to a serious accident in runaway or load rejection conditions. According to the experiential and theoretical analysis, the solution points to the fastening connection by a pin arrangement between rotor bracket and main shaft. Consequently, the unit has been running steadily under various working conditions. As there are numerous large, medium and small units in China facing the similar problem, the treatment scheme and design calculation methods proposed in this paper could be considered as a typical solution reference.

In order to solve the heat dissipation problem of heat pipe rectifier cabinet for excitation system of giant hydropower station, the working principle of loop heat pipe and the processes of development and improvement of loop heat pipe rectifier cabinet were introduced. The advantages of integrated loop heat pipe and horizontal symmetry structure, as well as its application in Wudongde Hydropower Station were analyzed. The practice shows the loop heat pipe rectifier cabinet adopting completely self-cooling heat dissipation mode is in a thermal stable state after long-term operation in the field, and a series of problems, such as dust, noise, power supply, maintenance, can be solved from the design principle. Meanwhile, it can improve the safety, reliability and automation level of the equipment and reduce the energy consumption, the benefits of energy-saving and environmental protection are obvious.