Water conservancy and hydropower projects have the characteristics of long construction period, complex structure, and being greatly affected by natural factors. An accidental factor in operation may sometimes lead to systematic safety accidents of the whole hydropower station. The author summarizes some typical cases of domestic hydropower station accidents in recent years, and analyzes some risk factors needing attention in the construction and operation management of hydropower stations, to provide reference for design, construction and operation management.

During investigation, design, construction and operation of tunnels, due to constraints and mistakes, failures happen. There are 10 cases at home and abroad presented in this paper, as well as the cause reasons and the lessons learned, for reference.

From the perspective of the role played by reservoir dams, the importance of reservoir dam safety to the realization of national water security strategy and dual carbon goals is emphasized. The safety operation of reservoir dams is always faced with severe situation and risks. By reviewing and summing up the safety supervision of hydropower dams, some suggestions are put forward.

Data abstraction and structure design are the foundation of application system construction, which are related to the practicability, scalability and stability of the system. Before the application system is put into service, the necessary work flow is to initialize the system, create an instance of the management objects for the system, and then applications are implemented. This paper, taking dam safety monitoring and management information system - iDam as an example, elaborates its basic data structure design and implementation of initialization, for reference.

Intelligent dam management platform based on online dam safety monitoring and BIM modeling for Xinfengjiang hydropower station has modules such as three-dimensional display of the dam, online dam safety monitoring and controlling, management of dam safety monitoring, intelligent patrol inspection, management of defect and hidden danger, intelligent report compilation, account and document of hydraulic equipment, task management and other functions. By use of the platform, the integration of information from various dam safety businesses is realized and the problems in traditional dam management are solved. This paper introduces the construction principles, development mode, system framework, database design and function modules of the platform, as well as the time node of system construction. Further, the operation of each module of the platform is analyzed.

In March 2019, affected by extreme freezing rain and drift ice, the Spencer dam in Nebraska burst after overtopping, resulting in one death and damage to some infrastructure. This paper introduces the accident process and emergency measures of Spencer dam, and analyzes the causes of dam break from the aspects of hydro meteorology, dam structure and operation management. The damage to hydraulic structures due to freezing load or freezing disaster has also occurred in cold areas of China. The reflection, experience and lessons of Spencer dam accident are presented here to provide reference for dam safety supervision and operation management in cold areas of China.

The“1·12”water inrush accident of Guanzhou hydropower station reflects the problems that the main responsibility of safety management is not implemented, the procedures of bidding and procurement are chaotic, and the quality of pipe bulkhead is poor. Enterprises in charge of the operation and management of hydropower stations should learn from this accident. In order to eliminate risk factors and ensure the operation safety of power stations, responsibilities of relevant departments should be fulfilled, technical management should be strengthened, and the sensitivity and responsibility of operation management personnel should be improved.

During the expansion of Chitan hydropower station, the blasting may affect the adjacent dam, powerhouse and switching station. In this paper, the important structures' dynamic response to blasting vibration is determined by three-dimensional dynamic finite element calculation. The results show that the safety of existing dam can be ensured by control of blasting parameters and by other protection measures in the process.

The calculation and analysis of dam break flood is an important basic work for dam risk assessment and emergency management. The size of dam break has a great impact on the calculation of dam break flood. At present, most research on the development of dam break is about earth rock dams, while the research on concrete dam break is less. So in the calculation of dam break flood, the geometric size of concrete dam break is usually assumed based on experience. According to the database of historical concrete dam break cases at home and abroad, combined with structural characteristics of concrete dams, the causes and failure modes of concrete dam break are counted and analyzed, and the general principle for estimating the size of concrete dam break is introduced, which provides a reference for determining the parameters of concrete dam break in flood calculation.

HK-968 elastic epoxy coating is modified by chemical toughening. It combines the elasticity of polyurethane materials with the strength and adhesion of epoxy materials. It cures at room temperature and has better durability on the concrete surface which exerts good effect on the treatment of difficult problems such as cavitation and abrasion damage of hydraulic structures. This paper introduces the development process of HK-968 elastic epoxy coating from the aspects including main agent selection,
performance tests and adjustments, durability tests and so on, and two application cases are presented, for reference.

Earthquakes, especially strong earthquakes, may easily cause dam accidents. The actual damage of the dam is determined by the earthquake intensity, which is related to the earthquake magnitude, hypocenter depth, geological structure and the distance between the dam and the hypocenter. To realize the graded warning for dams under the condition of earthquake, it is necessary to use the statistical model to quickly calculate the earthquake magnitude at the dam site and compare it with the design standard. By computer programming, the above-mentioned functions can be realized, which can quickly locate the dam that may be damaged by the earthquake and realize rapid early warning for the dam.

Consolidation grouting is very important for foundation treatment of hydraulic structures. The author mainly introduces the construction technology and related construction parameters of consolida-tion grouting through guiding pipe for dam foundation of hydropower station. It is proved by practice that the technology is feasible, economical and reasonable, and the grouting quality meets the requirements of design and specifications.

This paper describes the relationship between the dam safety video surveillance system and other systems, and summarizes the objects and contents to be monitored. Also, selection of right frontend device, communication, control, storage and display equipment based on the characteristics of hydropower dam and monitoring objects is introduced. In accordance with the principles of practicability, reliability, economy, advancement, maintainability expandability and upgradability, the dam safety video surveillance system is designed to meet the needs of dam safety management.

Patrol inspection is an important means to ensure the safety of hydropower stations. Based on summary of the advantages and disadvantages of traditional patrol inspection schemes, combined with digital inspection methods, this paper proposes an optimized scheme and a new online inspection system scheme is formed. Upgrading of inspection functions, the optimization of inspection types and content as well as the optimization of inspection systems are realized. After the scheme optimization, the degree of data structuring has been improved, the data redundancy has been significantly reduced, and the defect management function has been added. Moreover, the online inspection system designed based on this scheme has been applied to Ertan hydropower station.

The total depth of surge shaft and penstock shaft of a pumped storage power station in Israel is about 500 m. The excavation was implemented by front well drill method, which had high requirements for construction environment. There was a large amount of groundwater seepage during the excavation construction. The treatment by combination of curtain grouting and pumping was adopted. Before the construction of steel lining for penstock shaft, the seepage in initial linings was diverted to remove the influence on steel lining construction, which achieved good results. Meanwhile, the seepage treatment measures were improved from the perspectives of construction environment, construction quality and operation efficiency, which can provide reference for similar projects.

Inspection is an important means to grasp the safety status of dam operation. Inspection information reporting and management model is studied and established to supervise the process and quality of the inspection work of hydropower enterprises, timely discover structural anomalies found in inspections and establish an online structure safety evaluation system that integrates inspection results and instrument monitoring data as well as technical consultation methods for anomalies. In this way, the safety status of the dam is understood.

By inspection of hydraulic technical supervision of dams of Huadian Corporation, the problems and challenges are explained, mainly about management and in the specific equipment. Then plan is made for better hydraulic technical supervision in future. It is particularly important to take high dams, large reservoirs, small hydropower stations and defective dams as key supervision and management objects. Practical and effective measures should be taken to enhance management innovation and technology investment, which can ensure the safe and stable operation of Huadian Corporation dams.

The online dam safety monitoring and controlling system of Xinfengjiang hydropower station has established an online technology and method system integrating online monitoring management, monitoring and evaluation, intelligent patrol inspection, online structure safety calculation and evaluation. It comprehensively evaluates dam safety, and is at the top level in research and development of online monitoring and controlling technology for dam safety in China. The detailed scheme of development of the online dam safety monitoring and controlling system of Xinfengjiang hydropower station is proposed, including monitoring content, inspection of timeliness and effectiveness of measured values, index and abnormality identification method for single measuring point, information fusion method, evaluation rules, monitoring and evaluation scheme, patrol inspection and evaluation scheme, structure safety evaluation scheme, and et al. Finally, comprehensive evaluation of dam safety of the hydropower station is obtained.

With the development of information technology, the traditional paper-based hydraulic patrol inspection work is gradually transformed into a patrol inspection management system (module). At present, the patrol inspection system still has some problems. For example, the patrol inspection objects are not abstractly classified, the defects are not objectified, and the functions of patrol inspection App are simple. Aiming at the above-mentioned problems, the optimization design scheme is proposed and applied to the patrol inspection module in the dam safety information management system for Yalong river basin. Web terminal and mobile terminal (App) are mainly included in this module and functions such as viewing tasks, patrol inspection, result recording and query, defect tracking and query are available. With the help of information management means, this system can optimize the information management mode of hydraulic patrol inspection and further improve the level of dam safety information management.