Airport built on water in Japan is sinking into sea. All about the woes of Kansai International Airport

Japan's Kansai International Airport was touted to be the most unique airport in the world when it was built 30 years ago, but it is sinking at an alarming rate. Experts have expressed apprehension that it may sink one day. The airport that serves Japan's second largest metropolitan city Osaka, has already sunk more than 38ft. Some engineers have predicted that sections of the two artificial islands may sink another 13ft, to sea level, by 2056.

Hub of airlines

It is an enormous airport, that occupies two artificial islands in Osaka Bay. It serves as a hub for All Nippon Airways, Japan Airlines, and Nippon Cargo Airlines. But the £ 15 billion- Kansai International Airport is sinking quickly and moving further and further away from the city. The minimum elevation needed to prevent flooding in case of a breach in the encircling seawall is 13 ft. But engineers have that predicted that Kansai's islands would evenly settle over 50 years before stabilizing at 13ft above sea level.

£117million spent to raise seawall

A massive amount of £117million was spent to raise the seawall, which some would say was a futile attempt to prevent the inevitable. Talking to Smithsonian Mag in 2018, Yukako Handa, a representative of Kansai Airports said,"When the Kansai airport was constructed, the amount of soil to reclaim the land was determined based on necessary ground level and subsidence estimation over 50 years after the construction."

Airport on water

The land reclaimed from the sea was like a wet sponge and was transformed into a dry and dense foundation before it could support the weight of airport buildings. Construction crews laid sand five feet deep atop the clay seabed and installed 2.2 million vertical pipes, each nearly 16 inches in diameter. Afterward, these pipes were pounded into the clay and filled with sand, soil was used to create a stiffer floor.

Struck by extreme weather conditions

But, Kansai Airport has been repeatedly struck by extreme weather conditions. In 2018 the deadly typhoon Jebi struck, wreaked havoc across Japan and the airport was closed temporarily. Thousands of terrified passengers were stranded as the storm flooded the building and shook the infrastructure.

FAQs:

How was the airport built on water?
The reclaimed land was like a wet sponge. It was transformed into a dry and dense foundation before it could support the weight of airport buildings. Construction crews laid sand five feet deep atop the clay seabed and installed 2.2 million vertical pipes, each nearly 16 inches in diameter. Afterward, these pipes were pounded into the clay and filled with sand, soil was used to create a stiffer floor.

How important is Kansai International Airport?
Kansai International Airport is an enormous airport, that occupies two artificial islands in Osaka Bay. It serves as a hub for All Nippon Airways, Japan Airlines, and Nippon Cargo Airlines. It serves Japan's second-largest metropolitan city Osaka.