Wonderful Engineering

This Is The Truth Behind Japanese Fixation Of The Fukuoka Sinkhole In Just 2 Days

Source: BBC

Weren’t we all super impressed by how the Japanese fixed the Fukuoka Sinkhole in such a short period? Exaggerated by the media to have been done in 2 days, the hole was initially fixed in a week.

According to Japan times, the 15 m deep sinkhole that was 27 meters wide and 30 meters long appeared around 5 a.m on 8th of November. The hole that cut off utilities to around 800 households was considered to be caused by construction work on a subway line extension.

For fixing the sinkhole, a roller coaster was used to check the ground’s strength to identify potential safety problems. The hole got filled using a particular soil, produced by Kankyoushisetsu Resonant Incorporation. This soil when blended with water and cement becomes hard, even in water. The same soil is used at coal mining sites when similar cave-ins appear by experts with knowledge of mining accidents.

Around 3m of the hole was filled with the soil to make a platform for workers to repair the utility lines, sewage pipes and telecommunication lines. In the next few days, the complete hole was covered, and the road became open once again for traffic.

Many experts doubted if it was a long-term solution or just shoddy work to save Japan’s reputation. It was just a matter of a few weeks before the suspicion became a reality. In the first week of December, the road began to sink again. It happened because the synthetic soil may have compressed the soil underneath it as it hardened. The City officials say that the movement was expected as the sand and cement used to fill the hole takes some time to settle.

Knowing Japan’s Engineering efficiency and work ethics, most people were persuaded that the hole was completely fixed. But now, as the hardened soil continues to settle, it seems that the damage to Japan’s reputation is many times more than the actual damage to property.

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