In order to enhance the real-time capability of flood risk analysis and adapt to the dynamic characteristics of flood evolution, a 3D real-time flood risk analysis system based on the B/S architec⁃ ture has been designed. This system employs a coupled approach of the breach flow calculation software BREACH and the 2D hydrodynamic numerical model for dam-break flood calculation and simulation. It integrates WebSocket technology for real-time data transmission and utilizes Cesium 3D visualization platform to display the flood evolution. The core functional modules of this system are scenario manage⁃ ment, real-time calculation and calculation result analysis of dam-break flood, which can support dy⁃ namic management, real-time calculation and result visualization of the dam-break process. The system was validated through the case study of a reservoir. The results showed that the system can effectively re⁃ flect the flood inundation process, obtain reasonable calculation results, and enhance the intuitiveness of flood risk analysis and the decision-support capability through visualization technology

This paper provides a systematic summary of the current status and development direction of the standards system, regulatory system, management mode and technology for dam safety of China′s hy⁃ dropower stations. Responsibility shared among power enterprises, government departments and Large Dam Safety Supervision Center is established as the dam safety management mode of China′s hydropow⁃ er stations. China has released 101 effective standards and formulated a system table for dam safety stan⁃ dards. China has established a regulatory system centered around Regulations on the Supervision and Management of Operation Safety of Hydropower Dams. In the future, China will revise regulations, im⁃ prove standards and develop technologies to enhance the emergency response capability, informatiza⁃ tion, intelligence and internationalization level of dam safety, and promote the stable and far- reaching development of dam safety management.

Taking factors affecting the accuracy of static leveling as the starting point, this paper analyz⁃ es the degree of influence of temperature difference and barometric difference in pipeline, pipe diame⁃ ter, etc, and proposes corresponding solutions. Also, this paper analyzes bubbles, liquid corrosion, dew condensation on float surface, contact friction, sensor measurement error and other factors, and proposes corresponding optimization methods. The error propagation rule of the static leveling system is explained and the pipeline test process is described, which can check whether the static leveling system works nor⁃ mally. Through comparison and analysis of artificial leveling observation data and automatic static level⁃ ing data of a typical project, it is concluded that after taking various methods, the measurement accuracy can meet the requirements of specifications.

Based on the digital twin platform, the intelligent engineering safety analysis and early warn⁃ ing system is studied and designed. The mechanism model of engineering safety monitoring is studied by using the data mining, intelligent analysis and diagnosis technology. To obtain early warning indexes for specific project, the evaluation system and criteria are developed, which has realized intelligent safety analysis and early warning. Moreover, it has been applied to a project and resulted in improvement of the accuracy and timeliness of early warning, enhancement of the level of intelligence, and decisionmaking support for the operation management department.

The purpose of online dam safety monitoring of hydropower stations is to dynamically evalu⁃ ate the dam safety status in real time, which can provide technical support for preventing dam break, overtopping and major structure damage. The online dam safety monitoring system should be practical, effective and useful. It is necessary to develop and approve a practical and effective monitoring plan be⁃ fore system development. Based on the statistics and analysis of the causes of dam failures in the dam en⁃ gineering history worldwide, this paper explains the risk identification and monitoring elements of dam operation safety, and proposes suggestions for the content, items and information organization of online monitoring, to provide reference in the development of online monitoring plan.

Starting from the characteristics of emergencies and the requirements for emergency decisionmaking, this study treats dam operation emergencies as a continuous dynamic evolution process, propos⁃ es a scenario quintuple description method for dam operation emergencies, and constructs a Bayesian network model based on the evolution phases of target nodes. This model is applied to scenario develop⁃ ment where flood impacts dam operation safety. The approach reveals the intrinsic patterns and evolu⁃ tionary logic of emergencies, thereby enhancing the scientific rigor and operational feasibility of emer⁃ gency measures.

With the rapid development of pumped storage power stations, high-head hydraulic tunnels have continued to increase, and the operation safety of headrace tunnels has attracted more and more at- tention. Taking the shallow buried section of headrace tunnel in Huizhou pumped storage power station as an example, the main considerations for safety evaluation of shallow buried tunnel are explained re- spectively. The results show that although the shallow buried section of headrace tunnel has problems of broken surrounding rock and slightly insufficient thickness of overlying rock, the minimum principal stress and seepage stability at each control point can meet the requirements, and measures such as en- hanced consolidation grouting have been taken for the surrounding rock during construction process. Therefore, its safety can be guaranteed at present.

The Jiudianxia water conservancy project is located in the high altitude and cold area. Its dis⁃ charge tunnel on the left bank is easy to freeze due to the low temperature and the wind through tunnel. The durability of lining concrete in the tunnel is seriously damaged by the freeze-thaw cycle, which af⁃ fects the service life of the tunnel. This paper puts forward a design scheme of installing flat insulation gate at the opening of underground tunnel to solve the problems of seepage water freezing and cyclic freeze-thaw damage to the lining concrete.

In recent years, several disastrous tailings dam accidents have occurred at home and abroad, caused huge losses to the lives, property and environment downstream. A brief analysis of these typical accidents is conducted to summarize the cause reasons of the dam failure, with the aim of serving as a warning to industry insiders.

The design task of pumped storage project is heavy, the time is limited, and there are many disciplines involved. Therefore, traditional design methods are unable to satisfy the current situation and requirements. Using BIM technology, through meticulous application planning, the collaborative design is carried out, covering surveying, civil engineering, mechanical and electrical engineering, and other re - lated disciplines. It can significantly improve the rationality of design schemes, enhance the accuracy and quality of design results, increase the diversity of results, liberate the productivity of designers, and provide a solid foundation for the application of digital twin pumped storage power stations. This study briefly describes the way to choose a suitable 3D digital collaborative design solution for pumped storage power stations and carry out 3D digital design, as well as the value and advantages of 3D digital technol- ogy in the design stage of pumped storage power stations.

Limited by construction conditions, some concrete face rockfill dams have not built down- stream weirs, and only a certain number of osmometers are arranged, which can not reflect the dam seep- age situation through the leakage volume. Due to the complexity of seepage control of concrete face rock - fill dams, it is difficult to obtain the relationship between seepage pressure and seepage volume behind the concrete face by analytical method. In this study, the artificial neural network method is used to es- tablish the relationship model between seepage pressure and seepage volume of the CFRD based on its nonlinear mapping ability, and the measured values are used to verify it. The results by the leakage esti- mation method based on the training samples obtained from the three-dimensional finite element seep- age model are close to the measured results, which can provide a new way for leakage estimation of earth rock dams limited by geological conditions.

The opening and closing of transverse joints under strong seismic action have a significant im- pact on the dynamic response of arch dams, which is a key concern in the design of high arch dams. Us- ing the finite element time-history analysis method, taking into account of factors such as the opening of transverse joints in arch dams and the infinite foundation radiation damping, the calculation and simula- tion are conducted based on various working conditions composed of factors including normal reservoir water level and dead water level, design temperature rise and design temperature drop, and seismic loads under site-specific spectra. The analysis results show that the transverse joints in the concrete arch dam undergo repeating opening and closing during seismic response, with a relatively large opening occurring at a certain instant. However, the joint waterstop is not pulled apart. The arch stress of dam body is partially relieved, and the overall high-stress distribution of dam meets the allowable conditions, ensuring the overall stability of dam body after the earthquake.

The practical weir is common discharge control structure of spillway, and its head loss is an important parameter for calculating the spillway discharge capacity and the water surface line, as well as for the design of energy dissipator. The empirical formula for calculating head loss recommended by cur ⁃ rent specifications has low accuracy. Therefore, using the hydraulic boundary layer theory to derive the calculation formula of head loss of practical weir in spillway is of practical significance.

The anti-sliding stability analysis of gravity dams is one of the key issues in the safety design of dam engineering. Taking Jiaokou river reservoir as an example, based on actual engineering geologi- cal conditions and dam structure, the contact surface between concrete gravity dam and bedrock is deter- mined to be the anti-sliding stability control surface. The anti-sliding stability of the gravity dam foun - dation is systematically analyzed by two methods-theoretical formula calculation and discrete element numerical simulation, and the shear stability safety coefficient and the discrete element displacement contour with different strength reduction coefficients are calculated. The results show that the dam foun- dation is stable under all design conditions. The consistency between the calculated results based on specifications and the numerical simulation results is good. Further suggestions are put forward to strengthen the dam foundation surface treatment and arrange waterproof and seepage prevention facili- ties, which can be technical reference for similar projects.

The safety of hydropower dams is of significance for the lives and property of people, energy security, and the stability of economy and society. The dam safety monitoring system serves as the eyes and basis for supervising and evaluating dam safety, while routine monitoring and inspections of dam safety are a major task in the operation of hydropower stations. Timely detection of anomaly during dam operation requires not only a reliable dam safety monitoring system but also the practice of standardized and orderly monitoring and supervision. The former relies on technological advancement and progress while the latter depends on the continuous improvement of regulatory framework, technical standards, management concepts, as well as the competence and capabilities of personnel involved.

With the continuous increase in the number of operating hydropower dams in China, dam safe⁃ ty supervision is facing new situations and challenges. There is a growing need to apply intelligent tech ⁃ nologies to enhance the efficiency of supervision and ensure work quality. This paper discusses the appli ⁃ cation scenarios of intelligent technologies in dam safety supervision, particularly the function of genera ⁃ tive artificial intelligence represented by large model in automatic report generation, which provides a powerful tool for improving the efficiency of daily supervision tasks. This paper elaborates on the techni ⁃ cal principles and typical application examples, and puts forward new applications and directions for fur ⁃ ther enhancing the quality and efficiency of dam safety supervision with the development of technologies.

The safety technical standard system for hydropower dams serves as the safeguard mecha ⁃ nism for dam safety. In this regard, China has established specialized organizational bodies responsible for the planning, development and management of safety standards for hydropower dams. In nearly three decades of progress, standard development has been carried out in key areas such as safety monitoring, safety management and evaluation, safety risk assessment and emergency management, safety informati ⁃ zation and decommissioning management, gradually improving and refining the safety technical standard system for hydropower dams. This paper outlines the development history and achievements of hydro ⁃ power dam safety standards, elaborates future directions and tasks of standardization efforts, and intro ⁃ duces the latest released standards.

Based on the measured rainfall data in adjacent areas, this paper analyzes the distribution law of regional rainstorm, and uses statistical analysis method and contour map method to compare and analyze the design rainstorm. Through collection and utilization of reservoir operation data, the rain ⁃ storm time history distribution and runoff generation and concentration parameters are analyzed and se ⁃ lected in combination with domestic design experience. The SCS method and IWHA rational method are used to calculate the design flood of dam site, and the flood regulation calculation is carried out. Accord ⁃ ing to calculation, the layout of Kirirom Ⅲ hydropower station can meet the flood control requirements. The research method fully utilizes the measured data, providing reference for flood control design of small and medium-sized hydropower projects in overseas regions with scarce data, especially in South ⁃ east Asia.

Work summary and practical considerations on online safety monitoring technology for hydropow ⁃ er station dams// by ZHANG Xiuli// Dam Safety Monitoring Center of National Energy Administration Abstract: The author summarizes the progress and achievements of the Dam Safety Monitoring Center of National Energy Administration in promoting online monitoring technology development for hydropow ⁃ er dam safety over the past two decades, highlighting that online dam safety management is an essential component of the dam safety lifecycle management system. It is crucial to promote and implement online dam safety management widely. The author emphasizes that the development of online dam safety moni ⁃ toring system should focus on practicality, and proposes four key recommendations of prioritizing practi ⁃ cality, emphasizing research on monitoring schemes and indicators, ensuring meticulous and accurate processing of routine dam safety monitoring data and inspection results, and paying close attention to the planning, design and oversight of online monitoring platform development.