The characteristics of construction accidents are determined by the construction characteristics. The characteristics of< (1) "1"structure. The product is fixed, and the construction of personnel flow is the biggest feature of the product, which is fixed and personnel flow. Once the address of any building or structure is selected, the ground will be fixed when it is destroyed, but the production personnel will carry out production activities around it. The construction volume is large, and the production cycle is long, some months or a year, and some need 35 years or more. This has caused a limited space, a large number of operators, construction equipment, building materials and other businesses, which is different from other industries, personnel, product flow production characteristics are very different. The mobility of construction workers is not only reflected in a project. When a factory and a building are completed, the construction team will be moved to a new location to build a new factory or residence. These new projects may be in the same block, may be in different blocks, and may even be in another city. Construction teams will move around in neighboring areas, cities or regions. Since the reform and opening-up, the employment system has been reformed, which comes from the construction team of the vast majority of migrant workers. They not only have to follow the engineering process, but also flow according to the seasons (harvest and relaxation), which brings great difficulties to safety management. 2. Open-air construction is mostly high-opening, manual operation and heavy physical labor, and outdoor work accounts for 70% of the whole project, from basic building, main structure, roof engineering to outdoor decoration. Buildings from low to high, each floor is 2.9m, and the two floors are generally 5.8m, which is a house with more than seven floors. It is necessary to work in the open air with construction workers for more than ten meters, dozens of meters or even more than one hundred meters, and the working conditions are poor.

The construction industry in China has made great progress, but most jobs, such as Plaster workers, bricklayer, concrete worker and scaffolder, are still dominated by manual labor. Heavy labor, manual labor, bad working environment, such as light, rain, wind, thunder, etc. Operators do not attract attention or emotional excitement, and illegal business operations are very common. 3 & gt。 Changes in architecture and differences in rules; With the change of safety factor and progress, each building has different uses and different structures.

The change of image, different construction methods and different safety factors; Even the same type of buildings have different safety factors due to different technologies and construction methods; Even on the first floor, from the foundation, the main body to the decoration, every process is different, and the unsafe factors are different; Even the same technology, because of the different technology and construction methods, the safety factor is different. Therefore, the construction changes greatly and the rules are poor. The unsafe factors in the construction site change with the change of the project image, and change every month, every day or even every hour, which brings great difficulties to safety. As can be seen from the above characteristics, the protective facilities on the construction site must be adjusted and supplemented in time with the image development of the project progress to eliminate hidden dangers and ensure safety.

(2) Accident-prone categories

From the construction process and construction characteristics, it can be seen that the construction site of the main foundation roof workers in the sub-project construction is from the ground to the underground, back to the ground, and then to the sky. Often in an open, high-level, cross-operating environment. There are four main types of building casualties, falling, object impact, electric shock and mechanical damage. These four types of casualties have been as high as many years and are called "four major injuries". With the increase of the height of buildings from high-rise to high-rise, from first floor to second floor and third floor underground, especially in urban demolition projects, according to the analysis of national construction accidents in 2004, the number of casualties in the construction industry was 53.6438+00%, and the number of collapsed objects was 65.438+04.43%, accounting for 65.443%. The building has also become five