| Case Name |
A concrete wall collapsed during drainage canal improvement work in Tottori |
| Pictograph |
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| Date |
December 20, 1972 |
| Place |
Yurayado, Daiei town, Tohaku District, Tottori Prefecture |
| Overview |
In agriculture field maintenance construction field, the side concrete wall collapsed over workers when carrying out the excavation of drainage canal improvement work; as a result, 7 female workers were crushed to death, and 1 worker received the serious wound. |
| Incident |
Death from traumatic asphyxia by a collapse of concrete wall |
| Sequence |
On that day, the ground of the drainage canal was soft because of the long spell of rainy weather. Also, the concrete side wall was very unstable, since the bottom had been dug about 15 more centimeters by the construction 1 week before. In addition, no safety countermeasure had been made until the accedent occurred; the countermeasure was done just before the accident was just making support bars for the wall hastily.
The workers were hindered from noticing the collapse of the concrete side wall because their head were bent down to lay stone on the drainage canal bottom, and the dug sediment heaped up on the side of the drainage canal prevented them from climbing up from the drainage canal; these were the reasons why the workers failed to escape from the concrete wall. |
| Cause |
* The ground became soft because of the long spell of rainy weather.
* Since the dug up sediment had been heaped up on the side of drainage canal, the concrete wall collapsed due to the weight of the sediment.
* The workers worked while bending their heads.
* The concrete wall was in a very unstable condition, because the bottom of the drainage canal was dug 15 more centimeters 1 week before.
* Since the dug up sediment had been heaped up on the side of the drainage canal, it was difficult to run away from drainage canal.
* Any supports on the concrete side wall had not been done till just before the accident.
* Though this kind of construction work should start after the concrete side wall had been removed, they did not remove it for the sake of the cost cutback. |
| Response |
The field chief had noticed the danger, and was making the bracket of the log, but it was too late. |
| Countermeasures |
Safety and Health section of Tottori Labor Standard Office strengthened the instruction on the "support", such as the log on the concrete side wall, for this kind of the construction. |
| Knowledge Comment |
* We should execute futhter safety education and safety management in the construction field with inexperienced workers.
* This accident would be predictable, because they had already known the bottom looseness and the exposed bottom of the concrete side wall.
* It is necessary that we enrich the safety management countermeasure from the viewpoint of the materials and humans, that we predict possible accidents beforehand, and that we do not reduce safety costs. |
| Background |
This year, due to the recession by the over production of yam, house wives had to work in the construction field, where they were inexperienced, to get money for New Year.
On another front, the construction company had reasons that they had to employ inexperienced female worker. One was that, they were so small a company that they ran short of human resources and they had to source casual workers locally. The other was that the number of male workers was inadequate at that time. |
| Incidental Discussion |
In this accident, the excavation was carried out by manpower, although it had been designed to be excavaged by machinery. |
| Scenario |
| Primary Scenario
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Carelessness, Insufficient Precaution, Poor Value Perception, Poor Safety Awareness, Malicious Act, Rule Violation, Planning and Design, Poor Planning, Planning and Design, Poor Planning, Failure, Fracture/Damage, Bodily Harm, Death, Bodily Harm, Injury
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| Sources |
Mainichi Newspaper, Asahi Newspaper, Yomiuri Newspaper, Sea of Japan Newspaper.
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| Field |
Civil Engineering
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| Author |
KUNISHIMA, Masahiko (The University of Tokyo)
SUGIHARA, Keita (The University of Tokyo)
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