As the most important engineering structural material, cement concrete has been widely used because it has many superior properties, such as easy processing, low energy consumption, good durability, and can be combined with steel to form various load-bearing structures with different characteristics. It is suitable for large-scale production and construction, so it has been widely used. From the general industrial and civil buildings, highway and railway bridges, sleepers, poles, piles, pressure pipes, oil tanks and watertowers, to high-rise buildings, underground buildings, marine structures, nuclear power plant protective shells and pressure vessels, large-span space structures and high-rise tower mast structures, concrete structures have become an indispensable and widely used engineering structure material. In the past, it was generally considered that concrete is an experienced material, which is relatively simple from the selection of raw materials, configuration technology to construction application. However, since the late 1970s, concrete technology has made great progress and has entered the field of high-tech, mainly manifested in: (1) the great development of raw materials; (2) the rapid development of ready mixed (commercial) concrete and high-strength concrete technology; (3) concrete construction technology has made great progress; and so on.
水泥混凝土作为最重要的工程结构材料，因为具有易于加工成型、能耗低、耐久性好、与钢材结合可以组成各类不同特性的承重结构等许多优越性能，适宜于大规模生产和施工，所以获得了广泛的应用。从一般的工业与民用建筑、公路与铁路桥梁、轨枕、电杆、桩、压力管道、油罐与水塔等方面到高层建筑、地下建筑、海洋结构、核电站防护壳与压力容器、大跨度空间结构与高耸塔桅结构等，混凝土结构已经成为现代不可缺少的，将来越来越广泛使用的一种工程结构材料。过去一般认为混凝土是一种经验配置的材料，从原材料的选择、配置工艺到施工应用都比较简单。 但是从 70 年代末期至今， 混凝土技术已经有了很大的进展并已经进入了高科技的领域，主要表现在：（1）原材料有了极大的发展；（2）预拌（商品）混凝土与高强混凝土技术快速发展；（3）混凝土施工技术有了长足进步；等等。
Since the reform and opening up, China’s book industry has developed rapidly. As the manifestation of social consciousness, the formation means of social consciousness, as a tool to promote the ideological, political, educational, scientific and technological, economic development and social progress, it is necessary to conduct in-depth research on books in the new historical period, and form relevant theories to fully realize the role of books.
In today’s society, due to the highly developed Internet and the wide use of high-definition satellite images, intelligence work has less involved in “tracking, eavesdropping or prying open the safe” type of spying activities, and stealing and photographing are not the main ways of intelligence collection. The evolution direction of intelligence work is to become a branch of social science, pay more attention to the comprehensive analysis of opponents’ political, economic, social and military issues, and conduct comprehensive evaluation and prediction. Intelligence collection is no longer a furtive behavior. Although it is still necessary for the intelligence research institutions to protect the secret information sources of special importance, many information about politics, economy, society, technology, population and so on, as well as the basic social development trend and macro policies and data, are open to the public. They can be searched on the Internet and easily obtained from official documents. In the world, it is a trend to gradually move from national governance to open government affairs. The openness of these policies and data promotes the transparency of a country’s politics and the rationality of administrative law enforcement. Therefore, it will be a possibility and a reality to discuss the intelligence issue openly. As the mystery of intelligence is gradually revealed, intelligence research will become a branch of social science, and intelligence agencies will become more like a “think tank” to advise and advise the ruling party.
Water is the source of human life. From ancient times cities in various countries have been built near the water. Thanks to the water, cities have become prosperous, and generated different types of water culture. The emergence and development of any city are closely related to water at all times and all over the world. Both the expansion of city and the growth of population need water resources. Water is an important part of the ecosystem. Water and biological communities (including animals, plant and microorganisms) coexist in rivers and lakes, intertwined with each other through climate system, hydrological cycle, food chain, nutrient cycle and energy exchange. Water conservancy projects play a great role in the economy and society, at the same time, we should also notice that they have influenced river ecosystem to a variable extent.
Human activities including river regulation and dam construction have artificially changed the diversity, continuity and mobility of rivers, resulting in significant changes in natural conditions such as flow velocity, water depth, water temperature, flow boundary per se, hydrological laws and so on. The influence of all these changes on river ecosystem should not be ignored. The goal of river and lake controlling is not only to develop the functionality of rivers and lakes, but also to maintain the integrity of the watershed ecosystem. Clean rivers are the arteries of a sound ecosystem. Therefore, what should be made clear in the planning of flood control projects is that the river and biological communities in its upstream and downstream, left and right bank are all in one ecosystem. We should carry out unified planning, design and construction.
The construction quality of water retaining structures built on rivers not only affects the life and benefit of buildings, but also relates to the safety of millions of people’s lives and property in the downstream. Once the project fails, it will bring irreparable loss. Therefore, the water conservancy project construction must guarantee the construction quality.
Water conservancy and hydropower projects are mostly located in remote mountainous areas, sparsely populated and inconvenient for transportation. The workload of construction preparation is large and the preparation period is long. It is not only necessary to build traffic roads and construction plant facilities, but also to build office and living rooms. Therefore, great importance must be attached to the organization of construction preparation to meet the construction requirements and reduce the project investment. The construction of water conservancy projects on rivers often involves the interests of various sectors of the national economy, such as flood control, power generation, shipping, irrigation, fishing, logging, industrial and urban water use, etc. It is necessary to make overall planning and overall consideration, thus increasing the difficulty and complexity of construction.
The water conservancy and hydropower project is composed of many single projects, with concentrated layout, large quantities, many types of work, high construction intensity, and the limitation of terrain conditions, which is easy to cause construction interference. Therefore, it is necessary to make overall planning, pay attention to the organization and management of site construction, and select the optimal construction scheme according to the time and place by using the principle of system engineering. In the process of water conservancy project construction, the blasting operation, underground operation, underwater operation and high-altitude operation are often carried out in parallel, which is very unfavorable to the construction safety. Therefore, we must pay attention to safety construction and take effective measures to prevent accidents.
In recent years, the state has paid more and more attention to public infrastructure construction with economic development, and more water conservancy projects have been constructing. After water conservancy projects completed and put into use, the maintenance and management of them then become extremely important, because it will influence the operation, efficiency and service life. In the new period, the maintenance and management of water conservancy projects attract more attention in the construction and development of water conservancy projects. Based on this, the paper analyzes the current situation and carries out the practice of maintenance and management of water conservancy projects.
In the construction of water conservancy project, the effective management and maintenance need to be combined with practice, and with a scientific management mode, in order to realize the maintenance efficiency. In order to further study the maintenance and management strategies of water conservancy project, based on the effective work
experience and practice, the paper clearly analyzes the importance of water conservancy project construction and puts forward specific maintenance strategies. We hope to ensure the long-term development of water conservancy projects to meet people’s need and lay a good foundation for social and economic construction and stable development of society.