| Case Name |
Two workers suffered damage because of the collapse of a drilled slope, when working in the drilled hole. |
| Pictograph |
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| Location |
Laying drain pipe construction field. |
| Overview |
Two workers suffered damage when working in 2.5m-depth reclaimed surface, because of the collapse of a drilled slope. The causes of the accident were that the work was not done as had been scheduled, and that the investigation of the natural ground was also insufficient. |
| Incident |
To lay a drain pipe, they drilled a 1.8m-width and 2.5m-depth hole, and installed the 2.43m-length the Hume pipe (φ 700). When they descended onto the reclaimed surface to align Hume pipe, the drilled slope collapsed, and the two workers suffered injuries. |
| Sequence |
To lay the drain pipe, they drilled at 1.8m width and 2.5m depth,
and installed the 2.43m-length Hume pipe (φ 700).
Descending in the reclaimed surface, the two workers carried out alignment of the Hume pipe.
Then, the drilled slope collapsed, and the two workers suffered injuries. |
| Cause |
The gradient of the drilled slope was as steep as 83°.
It had been raining on the previous day, and the natural ground reached a condition so that it could collapse easily.
The operational procedure was not done as had been scheduled.
They did not confirm whether the operational procedure was done as had been scheduled. |
| Countermeasures |
1. We need to execute the work thoroughly based on the operational procedure.
2. Thorough investigation over whether the execution of the work is done as scheduled is essential.
3. We should make the operational procedure in response to situations such as the weather.
4. The monitoring person in the upper part is required, when working in reclaimed surface.
5. We have to make disaster databases in the office intranet; report every small misdoing, and reflect it in the same kind of accident prevention measure at the stage of construction plan-making. |
| Knowledge Comment |
* The natural ground after rain collapses easily.
* There definitely is a sign when the natural ground collapses, and we must not miss it. |
| Sequel |
* We need to make and follow work plans and operational procedures site by site.
* We certainly should force cooperation companies to make operational procedures, and to check and confirm that there is no difference between scheduled operational procedures and actual operational procedures.
* In the case of it being impossible to work as is scheduled in the operational procedures because of some circumstances, we have to force the cooperation companies to reform the operational procedures, and confirm the reformed operational procedure. |
| Scenario |
| Primary Scenario
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Carelessness, Insufficient Understanding, Ignorance of Procedure, Disregard of Procedure, Misjudgment, Misjudgment of Situation, Poor Response to Change in Environment, Change in Environment, Poor Value Perception, Poor Safety Awareness, Organizational Problems, Poor Management, Regular Movement, Dangerous Movement, Malicious Act, Rule Violation, Failure, Large-Scale Damage, Bodily Harm, Injury, Loss to Organization, Social Loss
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| Field |
Civil Engineering
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| Author |
IKAI, Seiji (ICHITEC CORPORATION)
BABA, Kanji (ICHITEC CORPORATION)
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