| Case Name |
Dump truck runs over the victim while walking in tunnel |
| Pictograph |
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| Date |
July 1, 2000 |
| Place |
Imajuku, Kawasaki-Town, Shibata-County, Miyagi-Prefecture |
| Location |
Road tunnel construction work |
| Overview |
As a 20 tons dump truck driver, the victim (29 years old) was engaged in carrying out the muck from the tunnel work face.Completing loading at around 3:45 p.m., he parked his truck in the right wall side which was about 120 m away from the working face and got out of the dump truck. Then he walked toward the working face again in order to do the next work, which was timber support assembly.While walking toward the working face, it seems that he directed other driver, whose empty dump truck was under standby, to go for loading of the remainding muck (rock and gravel dug up by the tunnel construction).The culpable driver (26 years old) reserved toward the working face, intending to follow the direction, then he ran over the victim who was walking about 65m ahead. |
| Incident |
The victim had been carrying out the muck with 20 tons dump truck until just before the accident.The muck loading operator, I, signaled to the victim that the mucking work had been completed by the method which the victim determined beforehand in the working face. This method means that the muck loading machine (the wheel loader for the muck loading) operator signals with a gesture, while sounding the klaxon one time when the final loading of muck was completed.The victim who received the signal (showing large "X" by both arms that means the completion of mucking) also forwarded it to other two dump truck drivers (the culpable driver and F). The two persons who received the signal sounded the klaxon to confirm the end of mucking in this cycle.After confirming repetition of the signal from the two dump truck drivers, the victim drove his dump truck about 40m to the pit mouth, then parked on the left side there. In the meantime, F drove his empty dump truck and moved to the point which was extremely close to the pit mouth.While F's truck was moving, according to F, he saw the victim get out of his dump truck.The victim moved
on foot to the working face.He moved because he was due to engage in the steel tunnel
support building work at the working face continuously.The culpable driver changed the direction
toward the pit mouth at the specified turn around place for dump trucks and intended to
approach the dump truck parking lot near the pit mouth, because he received the signal of the
mucking completion.Then, the dump truck of the culpable driver drove twards the working face in reverse in order to follow the signal. While driving the culpable driver felt that his
truck hit something and stopped, then he found the victim had fallen. |
| Sequence |
1. Outline of the related work.:It was the construction of double track road tunnel, and the construction period was 36 months.The bottom part of the excavation cross section was about 10 m in width and in an almost semicircle shape.The working face position was about 1,250 m from pit mouth when the accident happened. As the tunnel's nature of soil was hard granodiorite, they adopted a full cross section blasting method with the support bench.The operation procedure of excavation and transport of muck was as follows after the blasting has finished, load the muck onto the 20 tons dump truck by the wheel loader (side-dump type 2.8m3), and bring it to the surface.The speed of the dump truck in underground was strictly limited and they used to maintain the running in good condition by carrying out improvements and drainage.They used to put the carried out muck temporarily in the temporary place which was set up in the temporary yard, and later transported it to the soil disposal site in the specified place.Other workers except the person who was engaged in muck loading were forbidden to enter the site, and the work was carried out under enough lighting and
ventilation.After carrying muck out, work from the working face was completed, taking off
fragmented rock (scrape off) for preventing the swoop falling disaster using
backhoe (0.4m3) and large breaker (0.7m third-grade base machine with oil pressure type
1,300 kilograms). Also, the pit excavation for clearance security of steel tunnel support are
carried out.After the work of the above ends in the working face, the next work moves to the building
work of steel tunnel support.
2. Circumstances on site:The 500W mercury lamps were hanging from the ceiling as
illumination in the mine at the 11 m pitch, and so the brightness ensured there would be no
problem for the passage underground, and 1kw mercury lamps or
halogen lamps were locally illuminated in the workingface and underground working site.
The ventilation underground was by means of the exhaust system.The air with the dust near
the working face in the contrafan (800kw x 2) was forcibly exhausted through air pipes in
the underground, and the fresh outside air was blown space through the tunnel drift, and the
working face was supplied with air using the support fan.The underground had a pedestrian
alley on one side, since it was narrow, and the footway and the roadway had divided
with plastic chain and prop.Like the above, the construction field was tidy, and the
management of it was also satisfactory, and it was a superior workshop as a tunnel
construction field. |
| Cause |
Next fact is considered as a cause of the accident.
It concerns whether that the culpable driver directed the victimizer with "One more truck" was true.If it was true, naturally the question of how the victim knew that muck had remained in the working face is still unsolved.
- The victim entered the prohibited region on foot after he got out of the dump truck.It was the place where the dump truck reversed and naturally the victim himself who directed the culpable driver with "One more truck" was able to anticipate the movement.
- The culpable driver headed for the working face without paying attention to what was behind him. |
| Countermeasures |
1:We should always place the operation chief in the spot where he can look over the work. All operation chiefs and heavy machine operators should hand-carry the radio, and should make certain of indication, or report using it.
2:We should clarify the system of supervision and confirmation further.
3:We should improve the operation standard and enforce it fully among employees and workers.
4:We should install monitor camera for rear visual recognition in all dump trucks so as to eliminate any blind area.We should place display in driver's seat.
5:We should make off-limits notice to the muck carrying out work area on the electric bulletin board. |
| Knowledge Comment |
The fundamental form of communication is the exchange between two persons. In many cases, communication disorder between the driver of heavy machinery and people around him often brings accident.Though it is not a Tower of Babel's historical allusion, inevitably a discrepancy occurs on the production activity if we do not communicate the intention.As the result, an accident might occur.In the field, there are various agreements as signals between operator and peoples who intend to approach the machine.For example, "GUPPAR (pick rock or paper) campaign"This means, each shows "GU (closed fist, means rock)" or "PAR (open hand, means paper) between operator and the people around.In this method, communication is understood. That is to say, one expresses "Please stop the machine because I want to approach" and the other expresses "OK, I agree". It is a quite simple method.It might be a kind of sign language.From a long time ago, in the radio communication, such kind of knowledge has been accumulated in order to avoid misunderstanding and misconception. |
| Background |
The victim might have intended to convey completely different things to the culpable driver.Both the victim and the culpable driver should have the common recognition that the mucking in this cycle would be completed soon at the time when the accident occurred.Then, they could have clearly confirmed to each other that the excavation during the one cycle had been completed.Therefore, thinking about it calmly afterwards again, it is strange that if the victim driver had known the changed information then why did he take the time to get out of his truck and come to the culpable driver on foot in order to convey "One more truck please".However it is usual that additional truck one more is required at the working face.Members of a drivers' group must have often experienced such a case.There was no time for the culpable driver to sense the speech and behavior of the victim as strange, and moved his head and body with a conditioned reflex action.Rather, the culpable driver might have felt the opposite aspect such as "It is not funny either to ask me politely because he withdrew his previous signal".The following actions both of the victim and the culpable driver took are not strange, if the thing the victim requested was completely different matter and the culpable driver's inference proceeded like the above.As for the victim's personal single walk toward the working face, he might have guess that "The strictly prohibited walking" was canceled if he believed the mucking had been completed, although he knew that walking was prohibited while mucking.Believing the muck transport dump truck would not run for the time being, the victim might walk to the working face in the tunnel. In the meantime, it would be natural that the culpable driver of the dump truck judged that the mucking was carried out continuously.If it was the fact, it is assumed that the culpable driver paid attention on non-animate objects mainly, as it was believed there should have been no pedestrian in the area between the truck and the working face, according to the rules.Of course, by this fact, the duty of "Mind one's back" should not have been ignored. |
| Incidental Discussion |
The construction field was tidy, and the management of it was also satisfactory, and it was a superior workshop as a tunnel construction field. Both the victim and the culpable driver were employed for the same primary subcontractor.Also the culpable driver was a serious youth and worked together with his parent.Additionally, we mention here some other accident cases which were caused by mishearing and illusion, although some parts of those are merely based on guess work. When two workers were disassembling the shield machine used for tunnel construction, since the drive chain of the gondola car was cut off, while the gondola car on the scaffold was not fixed by lever block in the mobile scaffold frame, the gondola car slipped down, and the victim who was doing other work was caught in it and traumatized.Before the cutting operator cut the drive chain of the gondola car, he confirmed with the loud voice, calling the colleague (victim), who was not seen directly, "Did you stop XX?" and received the reply "I stopped it".Though this was proved later, the cutting operator asked his colleague the meaning of the confirmation "Is lashing OK?" so that the cutting operator might not fall from the gondola car, even if the chain was cut off.In the meantime, the victim had cut the switch of the electric system just before that, so he understood the inquiry of the cutting operator was concerned the switch, and replied like the above. |
| Reason for Adding to DB |
By a lack of mutual communication, the action of multiple parties concerned becomes uncoodinated, and discrepancy occurs often in real life.However, many of those end up with being laughingstock, a kind of funny story.In those cases, there is no actual harm.But, it might become a source of tragedy like this example, in the field where we handle or deal with considerable energy.We must change our way of thinking in the case that we move from every day life to the production field.However the accident mentioned above was the case where the person was unable to do so. It was shocking all the more because of that. |
| Scenario |
| Primary Scenario
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Poor Value Perception, Poor Safety Awareness, Carelessness, Insufficient Precaution, Usage, Operation/Use, Bodily Harm, Death
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| Number of Deaths |
1 |
| Field |
Civil Engineering
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| Author |
NAKANO, Masayuki (Japan Civil Engineering Contractors' Association)
KUNISHIMA, Masahiko (The University of Tokyo)
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