| Case Name |
A worker was stuck between sheet piles, when working without sufficient investigations. |
| Pictograph |
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| Date |
November 29, 2001 |
| Place |
Aichi Prefecture |
| Location |
The sewage pipe laying construction |
| Overview |
When doing earth retaining work on the loose natural ground, using a lightweight steel sheet pile, the construction worker dug so deep that natural ground collapsed, a lightweight steel sheet pile fell down, and the worker was trapped in the sheet pile. |
| Incident |
During excavation work to lay the sewage pipe using lightweight steel sheet pile, the disaster occurred. The construction work to lay a sewage pipe close to the water service pipe which had been laid a month before.
On the disaster day, after the morning gathering and KYT, they set to work. They did excavation work of confirming the position of the water service pipe, since it was laid near the construction field. The operational procedure in that day was that they confirmed the position of water service pipe, avoided it, installed a lightweight steel sheet pile, drilled to the predetermined depth, and laid a sewage pipe.
The natural ground collapsed, when two workers went down onto the reclaimed surface to install the jack in the waling (an object arranged in the horizontal direction, which supports sheet piles arranged in the vertical direction, prevents the soil break during digging a hole in underground).
The two workers were stuck between the lightweight steel sheet pile and waling. |
| Sequence |
From 8a.m. on the disaster day, after they had done the morning gathering and KYT, they set to work. The excavation was carried out by confirming the position of the water service pipe, since there was a water service pipe near the construction field.
They dug about 1.3m around the water service pipe with the drag shovel, and confirmed the position of the water service pipe. After that, they implanted lightweight steel sheet piles (2.0m) in the right and left at 1.5m intervals (the parent sheet pile), installed the waling, and finally the two workers descended in the reclaimed surface to install the jack in the waling.
Then (around 9:50 a.m.), the natural ground of the water service pipe side collapsed, and the two workers were stuck among collapsed sediment, the lightweight steel sheet pile and waling.
1 worker escaped by himself, and the other was rescued by his colleagues.
Since 1 worker was unharmed and the other was mildly bruised, they returned to the work from the afternoon. |
| Cause |
* Since the construction work was done shortly after the water service pipe construction had ended, the natural ground was loosened.
* They intended to install lightweight steel sheet piles, after they drilled to 1.3m. The setting of the lightweight steel sheet piles was shallow.
* They missed the sign of the natural ground collapse.
* They worked even though the preliminary survey and identification method of the buried object was vague.
* The workers' consciousness of safety was insufficient. |
| Response |
The colleagues helped the worker, but they did not go to hospital, moreover, they returned to the work from the afternoon. |
| Countermeasures |
1. We should implant the light weight steel pile at an earlier phase of excavation, such as when the first step of waling was finished.
2. We have to accurately grasp the position of buried object beforehand, by doing a number of trial pits, etc.
3. We should station a lookout man on the ground, when working an the reclaimed surface.
4. For the workers, some kind of training which encourages them to consider the prevention of risks and dangers of the work is required. |
| Knowledge Comment |
Let's work, after you accurately investigate the buried object. |
| Background |
* KYK was inadequate.
* The preliminary survey was insufficient.
* The safety and health education training was insufficient. |
| Account of Concerned Parties |
He was bruised all over his body. |
| Scenario |
| Primary Scenario
|
Carelessness, Insufficient Precaution, Ignorance of Procedure, Disregard of Procedure, Insufficient Analysis or Research, Insufficient Prior Research, Poor Concept, Poor Strategy or Concept, 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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| Number of Injuries |
1 |
| Field |
Civil Engineering
|
| Author |
IKAI, Seiji (ICHITEC CORPORATION)
BABA, Kanji (ICHITEC CORPORATION)
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