| Case Name |
The result in the execution of the road disaster recovery business which it didn't achieve the purpose of the construction, since it was remarkably different from the disign in the constructions of the block masonry revetment, etc.. |
| Pictograph |
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| Date |
1997 |
| Place |
The Hokkaido Yufutsu District Hobetsu town. |
| Location |
The enbankment field. |
| Overview |
Since the work was not carried out according to the drawing and specification in the block masonry revetment and the embankment construction, they have had possibility of collapse in rainfall time, etc.
Therefore, this remedial work was remarkably different from the design, and the purpose of the construction was not achieved, and government subsidies \ 5964,000 which concerned this were considered unreasonable. |
| Incident |
Revetment and embankment upon it had been be decided to be constructed as following in the drawings and specification, etc..
(a) The planned levee crown height of the revetment would be 56.33m in the origin side, and 56.49m in the end side, and its direct height would be 4.0m, and the depth of the part to be digged in the ground between the river bed and the levee crown of the revetment base would be 1.0m.
(b) Based on "the civil engineering works common specification" of the Hokkaido Construction Department supervision, the thickness of each embankment material layer would be made to be about 30cm in the condition of the appropriate water content, and compact it by small compacting equipment such as tamper and vibratory roller.
Construction of revetment and embankment appeared to be not appropriate as follows, when it was examined.
(a) Since that the value of the height was misread in the measure for setting the temporary standard height in the construction of the revetment, the levee crown height of the revetment hav become 57.28m in the origin side and 57.42m and in the end side, they were high in comparison with the design in the origin side in 95 cm and the end side 93 cm. In addition, the direct height of the revetment has been constructed high in comparison with the design in the origin side in 23 cm and the end side 24 cm each. Therefore, the depth of the part to be digged in the underground between the river bed and the levee crown of the revetment base was 28 cm in the origin side, and 31 cm in the end side, and it was remarkably insufficient than the necessary 1.0m depth.
(b) They have only shaped the slope the embankment by the backhoe, and they completely did not carry out the compaction by small compacting equipment such as tamper and vibratory roller determined in the common specification. |
| Sequence |
Construction of revetment of 13m in total length and embankment of 101.3m in upper part of the revetments composed of block masonrys and wall fixed to the both ends of that were carried out in fiscal 9 at \ 7455,000 ( government subsidies \ 5964,000 ) construction expenses as part of road disaster recovery business for restoring the town road Toyota Line in the Hokkaido Yufutsu District Hobetsu town which was struck by the torrential rain in August, 1997.
Since the construction was remarkably different from designing, they have had possibility of collapse in rainfall time.
After the completion, the river bed, etc. were eroded and block masonry of the revetment subsided by rainfalls in May, 1999, and the embankment also decayed.
This remedial work ( \ 7455,000 construction expenses ) was remarkably differing from the design, the purpose of the construction was not achieved, and government subsidies \ 5964,000 which concerned this were considered unreasonable. |
| Cause |
About the construction of the revetment, there seems to be error in measurement, but intention can be considered in case of remarkably differing from the designing, as shown in the superscription. And in the construction of the embankment, there also seems to be intention to avoid the control of supervision. |
| Countermeasures |
Multiple measure.
The measure by the multiple person. |
| Knowledge Comment |
The error in the initial stage is related for all back. Especially, it should be prudently done. |
| Scenario |
| Primary Scenario
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Misjudgment, Misperception, Planning and Design, Poor Planning, Poor Value Perception, Poor Organizational Culture, Non-Regular Action, Change, Failure, Fracture/Damage, Failure, Large-Scale Damage
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| Sources |
The 1998 fiscal year settlement inspection report ( Board of Audit ).
|
| Financial Cost |
Government subsidy delivery amount considered unreasonable : \ 5964,000. |
| Multimedia Files |
Fig2.revetment conceptual scheme
|
| Field |
Civil Engineering
|
| Author |
NAKAGAWA, Masafumi (The University of Tokyo)
KUNISHIMA, Masahiko (The University of Tokyo)
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