In view of the current problems such as less research on the combined support of anchor cable and frame lattice beam in slope reinforcement, the actual project of slope support on the left bank of a hydropower station was taken as the background. The stability of the original slope was analyzed by combining the limit equilibrium method and the finite element strength reduction method. The combined support scheme of anchor cables and frame lattice beams was studied. It mainly included anchor cable anchoring force calculation, anchor cable arrangement spacing, anchor cable length, optimal incidence anchoring angle and frame lattice beam size, etc. Finally, the support effect was studied by combining with numerical simulation. The results show that the original slope needs to be reinforced and supported. The error of the original slope safety coefficient obtained by the finite element strength reduction method is less than 1.5%-2.0% with the limit equilibrium method. The temperature loading method was used to simulate anchor cable prestressing for stability analysis of slope with combined support of anchor cable and frame lattice beams, and the combined support is effective and no obvious slip crack surface appears after the support. The study can provide reference for similar slope support projects.

Xiangjiaba Hydropower Station has six functions: power generation, navigation, flood control, irrigation, reverse regulation, sediment retaining. Since the project was put into operation in 2012, all other benefits except irrigation have begun to show gradually. With the completion of the first water intaking tunnel project of the north and south main canal of Xiangjiaba, and the comprehensive construction of the first phase project of the north general irrigation area, the research on the impact of irrigation water intaking on the power generation of Xiangjiaba hydropower station is an urgent work. Based on the adjustment calculation of 43 years series runoff during 1970-2013, inflow variation of Xiangjiaba hydropower station was calculated by considering the impact of the six large reservoirs regulation and storage in the upstream and water diversion in the Yunnan province. On this basis, the impact of water intaking after the first phase of north irrigation area, north second phase of irrigation area, and irrigation district being completed on the power generation of the Xiangjiaba Hydropower Station was analyzed. The research shows that irrigation water intaking reduces the power generation of Xiangjiaba, which is 1.78×10⁸ kW·h, 2.84×10⁸ kW·h and 3.78×10⁸ kW·h, respectively, compared with that before water intaking, and mainly in the dry season. After the intake of water in each period, the water discharge can be reduced by 109 m³/s at most, the annual average output can be reduced by 105 MW at most, and the number of installed hours can be reduced by 63 h at most.

With the development of deep learning and image recognition technology, monitoring the water level of urban rivers and lakes through video has become a hot research topic in recent years. In order to realize the comprehensiveness of urban river and lake water level monitoring, a method of river and lake water level identification based on Mask RCNN was proposed. The water level was obtained by the water level characters and their position relations in the video images, and it was verified by the monitoring video of the real water level station in Dongying City, Shandong Province. The results show that the probability that the comparison error between the water level identification result and the measured data was less than 2 cm was 68.5%, the probability of error less than 3 cm is 76.9%, the probability of error less than 5 cm is 93.5%, the average error is 2.1 cm, and the root mean square error (RMSE) is 3.0 cm, which meets the recognition accuracy requirements of video water gauge level in Technical Outline of Digital Twin Watershed Construction (Trial). Therefore, the model has a good recognition effect and a certain application prospect.

Pump device is the core of pump station, it is very important to carry out optimization research of pump unit. Taking the uniformity of axial velocity and the weighted average angle of velocity as optimization objectives, the hydraulic performance of inlet and outlet channels of a large vertical axial flow pump under pump mode and reverse power generation mode was optimized under all working conditions. Through the multi-scheme modeling of the inlet and outlet flow channels of the vertical axial flow pump device, the size of each section and the outer inverted line of the elbow section of the inlet and outlet flow channels were changed without changing the initial surface and the shape of the outlet section. The numerical simulation results of different inlet and outlet flow channels were compared. The distribution uniformity of flow velocity at inlet and outlet section of impeller, the average angle of weighted velocity, the hydraulic loss at inlet and outlet channel, and the variation rule of external characteristics and performance of axial flow pump device were analyzed in detail under pump mode and reverse power generation mode. The research results show that the hydraulic design of the flow channel under pump condition and reverse power generation condition can be considered comprehensively to improve the hydraulic performance of the pump unit under various operating modes in the design stage of the pump device for pump station. The research results provide theoretical support and engineering practice reference for hydraulic design and optimization of pump device in pump station.

Affected by the construction progress and other objective factors, the rock anchor beam may undergo loading with incomplete support, which seriously threatens the structural stability. In this paper, the rock anchored beam of a large hydropower station was taken as the research object. The three-dimensional nonlinear finite element simulation method was used to simulate the excavation of the main powerhouse and the filling of the rock anchored beam according to the actual excavation sequence. The continuous medium cementation element was introduced to simulate the weak contact between the beam concrete and the rock mass wall seat. The simulation results show that the load condition has a little impact on the stress and deformation of surrounding rocks, the initial support structure, and the rock anchor beam. The cementation surface between the surrounding rock and the rock anchor beam has a tendency to open, but it does not behavior obvious opening. The monitoring data such as the stress of the rock anchor beam and the deformation of the joint between the anchor beam and the rock wall remain basically unchanged, and no abnormal data are found, proving that the working state of the anchor beam is normal.

Evapotranspiration is a key process of energy exchange in the terrestrial-atmospheric system, and the selection of a suitable method for its accurate estimation is the basis and challenges to revealing the energy exchange process and the mechanism of Land-Atmosphere coupling under complex topographic conditions. Based on 60 years of meteorological data from 25 stations in the Red River Basin, China, the FAO56-Penman-Monteith method was used as a benchmark, and the MK statistical tests and Taylor diagrams were used to evaluate 8 potential evapotranspiration (PET) estimation methods from five aspeacts. The results show that the radiative methods Priestley-Taylor and Hargreaves had the best applicability, their results were closest to FAO (R²≈0.9); The temperature methods McCloud and Linacre were followed; The mass transport class methods Rohwer and Penman were worse. This study not only provided a highly adaptive PET estimation method for the Red River Basin, China, but also revealed the spatial and temporal distribution characteristics of the PET.

Due to the long-term operation in the low-load area, the hydropower unit deviates from the optimal operation area, resulting in large vibration of the unit, poor flow state of water flow, and other adverse consequences, such as cracks in runner blades and serious cavitation of the unit. In view of the complex flow conditions in the draft tube, this paper proposes two improvement schemes. Based on RANS equation, the standard SST κ-ω turbulence model is adopted to calculate the steady and unsteady solutions for three operating conditions of 0.45P_r(P_r is rated output), 0.60P_r, and 0.75P_r. The results show that the installation of the guiding device can effectively reduce the eccentric vortex band of the draft tube, and greatly reduce the pressure pulsation amplitude, so as to reduce the vibration of the unit. Considering the streamline of draft tube, vortex zone of draft pipe, turbine efficiency and pressure pulsation amplitude, especially the importance of pressure pulsation intensity to the stable operation of the turbine, it is concluded that the symmetrical arrangement of two diversion plates at the inlet of the draft tube has the better improvement effect on the Francis turbine. The results provide a certain theoretical basis for the safe operation of the hydraulic turbine unit under low load.

The dynamic changes of the water ecological footprint and carrying capacity of the representative cities along the first Phase Project of South-to-North Water Diversion East Route Project from 2010 to 2020 were analyzed based on the water ecological footprint and carrying capacity model. The SVR model was used to predict the water ecological condition of these cities from 2021 to 2025. The results show that the per capita water ecological footprint of Shandong displays a general uptrend, and the per capita water ecological footprint of the south section of Luoma Lake and Jiaodong Peninsula is at a high level. The per capita water ecological carrying capacity in the north of Luoma Lake and Jiaodong Peninsula shows an upward trend, while in the south of Luoma Lake and across the Yellow River, it shows a downward trend, among which the south of Luoma Lake is at a high level. The water ecological deficit or surplus of the representative cities along the line began to improve in 2013, indicating that the implementation of the project has a positive effect on the improvement of ecological environment. From 2021 to 2025, the water ecological footprint of Jiangsu section will increase and the water ecological carrying capacity will decrease. With the continuous increase of water consumption in various industries, the sustainable development of this region will face a great threat. Although the water ecological situation in Shandong section is developing well, it will continue to be in a state of water ecological deficit for a period of time, and the situation of water ecological pressure is severe.

Since the mechanical properties of dam materials can directly affect the settlement deformation and structural stability of core wall DAMS, it is necessary to explore the mechanical properties of soil-rock mixture and the internal deformation and failure mechanism by means of macro and micro in order. Taking the Rumei Hydropower Station in Tibet in Lancang River as research background, particle flow code (PFC) method based on discrete element was used to carry out large-scale triaxial numerical simulation test. The results show that with irregular enhancement in the form of block stone, the stress peak nodes was in advance, peak strength increased obviously with significant softening characteristics, shear shrinkage was not obvious, and the dilatancy is prominent; The shear zone evolved from a single “工” shape to a complex “工” shape. The thickness increases from 45 mm to 105 mm, and the final swelling failure area increases exponentially to 35 000 mm². The extreme value and the number of force chain strength increased. Increasing the stone content was the key to improve the peak strength of the sample. When the rock content was low, the shear shrinkage characteristic was prominent, and the dilatancy characteristic was not obvious. With the increase of the stone content, the “gear” effect of the block stone was enhanced, and the shear zone failure mode was transitioned from smooth reverse “S” shape to multiple irregular shear zones, with the thickness increasing from 47.5 mm to 105 mm, the swelling failure area evolving from 12 800 to 35 000 mm², and the number of strong chains increased. The extreme strength of the force chain was increased from 10.49 kN to 164.30 kN. In conclusion, it is suggested to select blocks with high irregularity and increase the stone content to enhance the structural strength stability. The research can provide reference for the stability evaluation of the project in the later stage and the work of the proposed dam.

In order to study the influence of loading rate on the damage evolution of hydraulic concrete, notched cubic specimens with side lengths of 300 mm and 450 mm were tested by wedge splitting test with different loading rates of 0.1 mm/s, 0.01 mm/s, 0.001 mm/s. Acoustic emission technology was used to monitor the acoustic emission signals of concrete in the damage process. Test results show that the variation of AE event rate during failure process of concrete can be divided into quiet, active, and attenuation period, among these the active period increases with the decrease of loading rate. The damage was defined according to the AE events, and it is found that the damage process of hydraulic concrete can be divided into three stages: crack initiation, acceleration and failure. The smaller the loading rate is, the faster the growth rate of the acceleration stage is. The damage evolution model based on the AE event obeys Weibull distribution, which can better reflect the influence of loading rates on the damage evolution of hydraulic concrete.