看雅思文章背雅思词汇：AIRPORTS ON WATER_雅思英语词汇

看雅思文章背雅思词汇：AIRPORTS ON WATER

　　The differences are both political and geological. Kansai was supposed to be built just one kilometer offshore, where the seabed is quite solid. Fishermen protested, and the site was shifted a further five kilometers. That put it in deeper water and above a seabed that consisted of 20 metres of soft alluvial silt and mud deposits. Worse, below it was a not-very-firm glacial deposit hundreds of metres thick.

　　The Kansai builders recognized that settlement was inevitable. Sand was driven into the seabed to strengthen it before the landfill was piled on top, in an attempt to slow the process; but this has not been as effective as had been hoped. To cope with settlement, Kansais giant terminal is supported on 900 pillars. Each of them can be individually jacked up, allowing wedges to be added underneath. That is meant to keep the building level. But it could be a tricky task.

　　Conditions are different at Chek Lap Kok. There was some land there to begin with, the original little island of Chek Lap Kok and a smaller outcrop called Lam Chau. Between them, these two outcrops of hard, weathered granite make up a quarter of the new islands surface area. Unfortunately, between the islands there was a layer of soft mud, 27 metres thick in places.

　　According to Frans Uiterwijk, a Dutchman who is the projects reclamation director, it would have been possible to leave this mud below the reclaimed land, and to deal with the resulting settlement by the Kansai method. But the consortium that won the contract for the island opted for a more aggressive approach, It assembled the worlds largest fleet of dredgers, which sucked up 150m cubic metres of clay and mud and dumped it in deeper waters. At the same time, sand was dredged from the waters and piled on top of the layer of stiff clay that the massive dredging had laid bare.