To fully consider the temporal volatility and randomness of runoff and associated source & load in the optimal dispatch of hydropower and reduce spillage water, a probabilistic prediction method of annual scenarios for hydropower runoff and associated source & load was proposed to simulate the typical annual temporal scenarios of average daily runoff and associated source & load and their probability of occurrence. Several typical ten-day scenarios were generated by clustering with a self-organization mapping net (SOM). Then a ten-day scenario simulation model was built based on a Markov-chain probability matrix, a multi-scenario conditional probability matrix, and the similarity principle— "the closer historical year, the larger weight." It ensures that the simulated scenarios accurately fit the statistical characteristics of actual data (randomness, seasonality, and conditional correlation) for intra-year and reflect the trend evolution year-to-year. Combined with the fluctuation checks, annual temporal scenarios were simulated by the Monte Carlo method. Finally, the k-means scenario reduction was used to obtain typical annual temporal scenarios and their probability of occurrence. The results of an actual hydropower example show that the proposed method has the advantages of high accuracy, strong adaptability, and comprehensive prediction information.

For Guxian hydro-junction project, concrete volume is huge, and the construction period is tight, construction technology and parallel planning are key problems in the construction of high RCC gravity dam. Therefore, the simulation technology of discrete event system was introduced to establish the construction simulation model in line with the dam type characteristics of the dam to simulate and calculate the construction process of concrete partition, parallel and jump warehouse. After multi-scheme simulation, the flat inclined layer technology and the corresponding warehouse surface partition scheme were recommended, and the warehouse surface control criteria were put forward. It provides all-round data support for Guxian project, and its simulation model can be used as a reference for other similar projects.

In order to overcome the difficult problem of establishing multi-factor and non-linear complex relationship of reservoir sand discharge and achieve its accurate prediction, four machine learning algorithms including XGBoost, KNN, SVR and RF were used to predict and analyze the sand content of reservoir outflow based on the series data of Wanjiazhai reservoir from 2002 to 2020, respectively. The results show that the use of machine learning algorithms can effectively realize the reservoir discharge prediction considering different influencing factors. The applicability of different machine learning algorithms in reservoir discharge prediction varies. In comparison, the highest coefficient of determination R² of the reservoir discharge prediction model based on RF algorithm is 0.9349, and the corresponding average absolute error and root mean square error are the smallest, which are 2.974 and 4.886, respectively. The prediction effect of the RF algorithm is better than the other three algorithms. The proposed method can provide a theoretical basis for accurate prediction of reservoir sand discharge and optimization of scheduling scheme.

It is significant to achieve safe operation of the project and strengthen the construction of the whole life cycle safety supervision system of the dam to scientifically and rationally conduct a comprehensive evaluation of the earth and rock dam seepage control treatment scheme. From the four guideline layers of engineering risk removal effect, engineering management, engineering economy and engineering construction, this study constructed the evaluation index system of earth and rock dam seepage control treatment scheme. Aiming at the evaluation of the risk attitude of decision makers in the process of seepage control program selection, the risk attitude factor was introduced to assign interval evaluation to the indicators, and the subjective and objective weights were optimized based on game theory. And then the program was analyzed and evaluated using the improved TOPSIS model. The effectiveness of the preferred system was tested by taking a reservoir anti-seepage treatment alternative as an example. The results show that the method is feasible and effective for the selection of seepage control solutions.

Goss error detecting method of monitored dam deformation data is researched based on the fully convolutional neural networks (FCN). Firstly, the method of representation learning of artificially labeled data sets by FCN model was proposed to simulate engineers’ experience. Secondly, the FCN model for gross error detection was built and artificially labeled data sets were used for model training. Finally, the trained FCN model was used for gross error detecting of monitored deformation data of a gravity dam. The results show that the gross error in monitored dam deformation data can be accurately obtained by the proposed method, which can improve efficiency of dam safety management.

As an efficient, environmental and energy-saving transportation technology, the wheeled capsule transportation has promising application prospects. When the pipeline carriage was stationary in the pipe, it could be regarded as a crossing-cylinder structure. When water flowed around the structure, the vortices existed, which would cause energy loss. Therefore, the hydraulic characteristics at the downstream of the flow field around a pipeline car and the spatial vortices structure after the stabilized flow field were studied by numerical simulation, model test and theoretical analysis. The results show that the near-field areas of the downstream flow field of wheeled capsule with different diameters could be divided into the reflux zone and the jet zone. As the distance rose, the section-averaged velocity had a tendency of declining then rising in the near-field, and recovered the section-averaged velocity of pipe at the distance of the length of capsule. And in far-field, with the distance rose, the fluctuation of section-averaged velocity was gradually decreased, and the flow became stable. The eddy ring structures in the field were highly fractured, eddy structures were more on the side near the annular gap and less on the side near the pipe axis.

As a common safety problem in water diversion engineering, water hammer is often caused by abnormal operation of valves, So, it is necessary to conduct a comparative analysis of water hammer problems under different valve adjustment methods. The CFD technology and dynamic mesh technology were used to simulate different single and double valve adjustment modes, and analyze the fluctuation of water hammer pressure at different locations in the pipeline. The results show that when the single valve is adjusted, the first fast and then slow closing valve mode has an inhibitory effect on the water hammer within a certain range of fast shutdown; The fast closing amount is too large, which will play a worsening effect of water hammer; When the fast shutdown amount is 60%, the water hammer pressure can be effectively controlled, and the water hammer will deteriorate when the fast shutdown amount is 80%; When adjusting the double valve, considering the pressure before and between the two valves, it can be found that the “first 0.25 s off 60%, the last 0.25 s off 40%” method can avoid the occurrence of excessive pressure and negative pressure. The research result provides a design and operation scheme for the rapid shut-off process of the valve in practical engineering.

In order to reduce the negative pressure of the steps, reduce the influence of cavitation erosion and improve the effect of step dissipation, the trapezoidal energy dissipation pier was added into the convex angle of the traditional steps to form trapezoidal energy dissipation pier and step combined energy dissipator. The method of combining hydraulic model tests and numerical simulations was used to study the hydraulic characteristics of trapezoidal energy dissipation pier and step combined energy dissipator. The results show that there is negative pressure on the horizontal and vertical surfaces of the trapezoidal energy dissipation pier and step combined energy dissipator near the convex angle, and there is a possibility of cavitation failure; However, the aeration concentration of the negative pressure area in the horizontal level and the vertical surface of the step is basically greater than 5%, which can effectively reduce the harm of cavitation erosion; Within the study range, the trapezoidal energy dissipation pier and step combined energy dissipator energy consumption rate can reach more than 70%, and the energy dissipation rate decreases with the increase of the flow rate. This combined energy dissipator is conducive to reducing the cavitation hazard of step and improving the effect of step energy consumption, which can provide a certain reference basis for the design of step energy dissipator and existing step spillway reinforcement.

Vertical seam fishway has gradually attracted the attention of hydraulic engineering field because it can adapt to large amplitude water level, obvious energy dissipation effect and stable flow pattern. In this paper, the influence of the length width ratio of the pond on the hydraulic characteristics of the opposite side vertical slit fishway was studied by numerical simulation. The results show that the change of the length width ratio of the pond has little impact on the dissipation rate per unit volume; The attenuation along the main flow area first increases with the increase of the length width ratio of the pond, and then remains unchanged. The larger the length width ratio of the chamber is, the closer the maximum velocity in the chamber is to the vertical joint; The ratio of the main flow velocity to the maximum flow velocity (the maximum variation of the main flow velocity along the way) is within a certain range. The length width ratio of the pond is between 1.00-1.13, which can obtain better water flow pattern, larger reflux area and better water quality in the mainstream area of the fishway.

In order to solve the cavitation damage problem of the spillway with high head, three schemes were proposed. The aeration tank was added at pile number 0+130.73, 0+161.78 and 0+186.39, respectively, and the corresponding Fr was 6.65, 7.91 and 8.53. By means of RNG κ-ε turbulence model and physical model test, the aeration concentration and cavitation number indexes of the section prone to cavitation erosion were analyzed. The results show that the effect of adding aerator at pile 0+186.39 is better than the other two schemes, and the bottom aeration concentration is above 15% and the flow cavitation number is greater than 0.3 in the section prone to cavitation erosion, the cavitation failure problem in the drainage channel section can be effectively solved.