| Case Name |
The buried object (optical fiber cable) was damaged by the excavation by the backhoe. |
| Pictograph |
|
| Date |
January 16, 2003 |
| Place |
1334-17, Kizu, Muya town, Naruto City, Tokushima Prefecture |
| Location |
The No.11 information BOX installation construction field in 2001 fiscal year |
| Overview |
The excavation of No.2 concrete box (handhole) and information BOX crossing under the roadway was carried out by hand, believing because of the drawing occupied by NTT that the pipe was laid in sidewalk. The NTT pipe line (1 out of 6 sections) was cut off, when they drilled the roadway by the backhoe (0.25 cubic meter). |
| Incident |
Though they had confirmed that the construction field was close to NTT's underground installation, judging by the drawing, they thought there was no danger of damaging a buried object, if excavating by hand. Therefore they worked without NTT observation (they did not ask them to come) on that day. |
| Cause |
* The person in charge judged that the observer from the occupancy enterprise was not necessary, and the work was done according to the drawing.
* The drawing of the occupancy enterprise was different from the actual place.
* They belived that the buried object was not under the roadway crossing section, therefore they drilled with the backhoe. |
| Response |
They contacted NTT, did temporary measures, and changed the cable about 800 m-long as soon as the cable was prepared. |
| Countermeasures |
* We should work with the monitoring person from occupancy enterprise, or stop working.
* After asking for the occupancy enterprise's observation and making the differences between the drawing and the actual place clear beforehand, we should start working.
* Adjustments should be done by the communication in the everyday preliminary arrangement.
* The person in charge needs to confirm that the work is done as outlined in the preliminary arrangement.
* If the work is not done as in the preliminary arrangement, we have to interrupt working.
* It is desirable that a survey instrument is used in order to grasp a buried object. |
| Knowledge Comment |
* We have to forbid the thoughtless and individual judgment.
* The cooperation between the builder and the occupancy enterprise is essential.
* A company should regulate the use of survey instruments for the work which is related to buried objects. |
| Sequel |
Since we experienced the hardship of the accident treatment, we will do our best for the prevention of such accidents. |
| Reason for Adding to DB |
To prevent the repetition of the accident related to the buried object |
| Scenario |
| Primary Scenario
|
Insufficient Analysis or Research, Insufficient Prior Research, Misjudgment, Misjudgment of Situation, Ignorance, Insufficient Knowledge, Regular Movement, Careless Movement, Failure, Fracture/Damage, Loss to Organization, Social Loss
|
|
| Physical Damage |
Cutof 1 section of the optical fiber cable |
| Financial Cost |
About 3 million yen |
| Economic Loss |
About 4 million yen |
| Consequences |
They suffered a nomination stoppage |
| Field |
Civil Engineering
|
| Author |
WATANABE, Kuniomi (Japan Road Contractors Association)
|
