The flexible apron of sluice of Xinglong water conservancy project is introduced, and the underwater structure, geological conditions and flexible apron structure are analyzed. After the autumn flood of Han River in 2017, the underwater survey results showed that the flexible apron downstream of sluice was damaged, which posed a threat to the operation safety of the project. Based on the actual damage of flexible apron, the damage repair schemes are analyzed and compared with each other, and the practical scheme is selected, which has brought about good results in practice.

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.

As time goes by, aging would be found with the concrete dams which can be attributed to physical and chemical reactions.In detail, the integrated elastic modulus and safety margin would decrease and rehabilitation is critical to safety operation.This paper analysed the aging process of concrete dams and discussed their expected life span.

Based on the analysis of seepage quantity from dam body, the main causes and possible seepage channels in the dam body are determined. Accordingly, the design scheme is proposed and carried out, and its effect is evaluated.

Multi-point displacement meters are widely used in deformation and displacement monitoring of slope rock mass and cavern rock of water conservancy and hydropower projects, which can realize automatic monitoring and safety warning. The new multi-point displacement meter device introduced in this article is a new structural type different from the old described in DL/T 1272—2013, including an anchor head, a transmission rod (steel pipe) and a plastic protection tube installed with concentric shafts, as well as the orifice mounting base and the matching displacement sensor. Its application range and measurement accuracy are exactly the same as the multi-point displacement meter device, and its technical performance is superior. It has advantages such as high equipment precision, easy installation and high observation accuracy. Moreover, one of its important technical achievements is realization of the dual functions of manual instrument measurement and automatic measurement by displacement sensor, which can be used to verify the automated measurements and realize the continuous observation by use of the manual measurement data during replacement of the displacement sensors.

As a major producer of hydroelectricity in the world, Brazil has rich experiences and its own characteristics in dam safety management. Based on regulatory requirements, laws and regulations, safety assessment and emergency management of Brazilian dam safety, the dam safety management practice of CTG Brasil is shared for reference.

This paper focused on the main characteristics and seepage causes of diseased embankment dams. By introduction of the mechanism and effect of some treatment methods, such as grouting and concrete anti-seepage wall, the paper put forward some optimized programs and pointed out the issues that attention should be paid to in construction, for reference.

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.

Shanmei Reservoir is a large, multi-functional water conservancy project which put in to operation in1972. Based on the defor-mation observations of the dam during the30years, this paper analyzed the partial defect of the project and pointed out the evaluation and suggestion.?

Analysis on wetting deformation of upstream dam shell in 635 clay- core gravel sand dam was performed, via the double yield surface model and the empirical formula through test result statistics. The deformation mainly concentrated upon upstream clay core because of wetting deformation of gravel sand, and the computed results was accordant with the test data. It was of great significance for construction materials choosing and damsafetymanagement.

The automatic monitoring system of Manwan hydropower station has been in operation for 11 years. This paper introduced the main problems in operation. Accordingly, some innovation measures were implemented and good effect was achieved.

After years' operation, seepage may occur at earth dams. This paper analysed the types and cause reasons for seepage, and, accordingly, advanced some preferred treatment schemes and issues calling for attention in construction, for reference.

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.

Application of high- pressure gunite in foundation anti- seepage treatment is of the advantages such as easy construction, short term and good quality, especially in deep layer permeable layer treatment. This paper introduced the design and construction of high- pressure gunite for gravel layer foundation at Hongshan reservoir, for reference.