Cause analysis of falling accidents in the constru

2022-08-26
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Cause analysis of falling accidents in hydropower construction and production

this news: through itemized cross statistics and analysis of falling accidents in hydropower construction and production from 1993 to 1999, various causes of falling accidents in hydropower construction and production are revealed, which provides a certain basis for formulating accident prevention countermeasures

keyword accident causes unsafe behavior unsafe state

introduction

in hydropower construction and production, falling accidents from height are always a high probability event in hydropower construction industry, which should also be comprehensively considered according to the current development scope of enterprises and customer requirements. Therefore, their occurrence frequency is high and the probability of casualties is high. The author counted the major casualty accidents in hydropower construction and production from 1993 to 1999, including 30 cases of falling accidents and 31 deaths. The number of cases and deaths accounted for 22.39% and 18.34% of the total number of cases and deaths respectively. Among these 30 falling accidents, there are 27 cases with more detailed information. Now statistics and analysis are made on these 27 cases from different aspects

1 itemized statistics and analysis

1.1 analysis of the party's activity state

the so-called Party's activity state refers to the behavior state in which the injured person, that is, the party is engaged in a certain operation or doing a certain thing at the moment of the accident. In statistics, the activity status of the parties is divided into two categories: operational status and non operational status. In this statistics, 14 accident parties are in the working state, and 13 accident parties are in the non working state, mainly in the process of walking and moving. In 27 cases of falling accidents from height, the parties involved in a wide range of operations, including more than 20 operations, such as formwork operations, wall building operations, installation of gate water seals, inspection of dangerous cliffs, line erection, rope recovery, laying of roof panels, treatment of concrete pump pipe joints, and more concentrated on formwork operations. The statistical results are shown in Table 1

Table 1 Statistics of the parties' activity status

see table

1.2 analysis of the parties' falling position

cross statistics of the parties' falling position and state were carried out. It was found that there were 23 falling accidents in the air and near the edge, accounting for 85.19% of the accident statistics; The hole falling accidents are relatively less, and mainly in non operational state. The statistical results are shown in Table 2

see table

Table 2 victim fall location - operation status statistics

in air and edge falling accidents, the highest fall height is 39m, and the lowest is 2.5m; In the hole falling, the highest falling height is 30.0m and the lowest is 5.9m. The falling height spans four levels of high-altitude operation, which shows that no matter the first-class high-altitude operation or special high-altitude operation, and no matter what activity state the operator is in, as long as the operator is within the scope of potential energy danger, there may be falling accidents, which cannot be taken lightly

1.3 statistics of injury causes

in the process of hydropower construction, there are four main reasons for human injury: unsafe behavior of people, unsafe state of things, management factors and uncontrollable factors of manpower. Human uncontrollable factors refer to non human controllable factors, such as sudden flash floods, debris flows, etc. the probability of such accidents is extremely low. The first three factors are often intertwined in industrial accidents in hydropower construction and production. This means that the accident is the result of many factors, but some are direct causes and some are indirect causes. Now, the direct cause refers to the cause that directly leads to the accident, and the indirect cause refers to the cause that makes the direct cause produce and exist. Of the 27 falling accidents counted this time, 21 were directly caused by human unsafe behavior and 6 were directly caused by the unsafe state of objects, as shown in Table 3

see table

Table 3 injury cause statistics

self injury in the table refers to that the direct cause of the party's injury is caused by himself, such as the human body out of control due to excessive force during operation, instability when standing, careless footfall when walking, etc. Being injured by others means that the direct cause of the party's injury is caused by others, such as being injured by an accident caused by others in the process of working or when passing through a workplace. The unsafe state of objects means that the direct cause of the injury of the parties is the insecurity of equipment, facilities, materials and the environment, such as the sudden collapse of the pole makes the personnel working on the pole fall with the pole, and the sudden fracture of the upright brace of the scaffold leads to the imbalance of the human body. Further analysis of its deep-seated reasons, there are many indirect reasons behind each accident, including management defects

2 analysis of causes of falling accidents from height

2.1 analysis of causes of accidents

in 23 cases of falling accidents in the air and near the edge, there were 12 cases in which the original data clearly recorded that the safety belt should be fastened but not fastened, of which 9 cases were in the working state and 3 cases were in the non working state. Among the 9 cases in operation status, there are 7 cases of template operation. According to the regulations, "when working at heights suspended from the dam crest, steep slopes, roofs, cliffs, towers, suspension bridges, scaffolds and other dangerous edges, safety or protective railings must be erected on the free side. Operators must fasten safety belts and wear safety helmets." In fact, of the 23 airborne and edge falling accidents counted this time, only 4 cases were fastened with safety belts. In these 4 cases, 1 case was tethered incorrectly, and 3 cases removed the seat belt while moving. However, the scaffold near the air and edge is very simple, without protective railings and safety protection. This means that the person concerned is completely exposed to potential energy danger, and his life only depends on the reliability of the human body itself. It is inconceivable that such a dangerous working environment, the parties are used to it, almost taking their own lives as a joke, even the safety belt is not tied! What is the reason why the operator believes that there is no problem without wearing a seat belt? Between the lines of the original data, it is difficult to find this deep-seated reason. What is the mentality of the operator? This is a question worth exploring

in the statistics of falling accidents from height, the proportion of the parties in the non working state cannot be ignored, and nearly half of the accidents occur in the non working state. For example, on the way to the working face, when climbing the scaffold, what objects need to move back and forth on the working face. In this kind of situation, the parties often do not wear safety belts, or some parties originally wear safety belts and remove them when moving. The reasons are: first, it is inconvenient to fasten the safety belt when moving; second, there is no condition to fasten the safety belt, such as walking in the tunnel or crossing the side wall into the warehouse surface. Therefore, falling accidents from height during movement are a persistent disease of safety protection for high-altitude and edge operations in hydropower construction industry, which should be fully reproduced

2.2 event tree analysis of airborne and edge falling accidents

in the airborne and edge falling accidents in this statistics, there are 11 cases with high requirements for coordination stability with human body imbalance as the direct reason. The main reasons for the imbalance of the human body are: excessive force during operation, excessive concentration, foot slipping, formwork vibration bullet hitting the human body, scaffold cross bar loosening, scaffold brace fracture, etc. In the process of working at heights, once the human body is out of control, the danger has actually appeared, but the consequences are different. The best consequence is also a dangerous incident. Because people are flexible, they maintain a balance; Or just grasp a stable object, prevent the further development of the situation, the event ends, and the human body turns the corner. Although there are few statistical data on this situation, there are a lot of hardness tests in the construction process, while the Leeb hardness HL and shore hardness HS belong to the rebound method. If the human body fails to maintain balance, the situation will further develop and the human body will inevitably fall. At this time, safety protection facilities play a crucial role. The evolution of the situation is shown in Figure 1

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Figure 1 human out of control event tree in high altitude operation

from the perspective of accident prevention, as long as we cut off any failed branch in the development process of the event tree, we can prevent the event from developing in a more serious direction. Unfortunately, in these 23 fall accidents, there were no safety protection facilities on the air and edge surfaces, and the operators did not function or use the safety belt correctly, which made the event develop smoothly towards the failed branch. From the time sequence analysis, the loss of control of the human body led to the fact that covestro was cooperating with Henkel, the adhesive manufacturer, and the fall incident occurred first, while the safety protection facilities played a later role. Therefore, safety protection facilities, including personal protective equipment - safety belts, can only prevent the development of the situation at best, but cannot prevent the occurrence of events. This idea of accident prevention itself is negative, but even this, we have not achieved

3 conclusion

from this statistics and analysis, it can be seen that the falling accidents from height in the process of hydropower construction and production have the characteristics of wide operation range, large fall height gap, large proportion of falling accidents from height in non operation state, and high probability of falling accidents in formwork operation in operation state. In addition, the on-site management of work at heights is not optimistic. In this statistics, 85% of the parties did not wear safety belts when working in the air and near the edge, and the air and near the edge were lack of safety protection facilities, and the holes, holes, wells and grooves were lack of barriers and obvious warnings

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