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

　　Nor was the sand the only thing used. The original granite island which had hills up to 120 metres high was drilled and blasted into boulders no bigger than two metres in diameter. This provided 70m cubic metres of granite to add to the islands foundations. Because the heap of boulders does not fill the space perfectly, this represents the equivalent of 105m cubic metres of landfill. Most of the rock will become the foundations for the airports runways and its taxiways. The sand dredged from the waters will also be used to provide a two-metre capping layer over the granite platform. This makes it easier for utilities to dig trenchesgranite is unyielding stuff. Most of the terminal buildings will be placed above of pile-driving foundations above softer areas.

　　The completed island will be six to seven metres above sea level. In all. 350m cubic metres of material will have been moved. And much of it, like the overloads, has to be moved several times before reaching its final resting place. For example, there has to be a motorway capable of carrying 150-tonne dump-trucks; and there has to be a raised area for the 15,000 construction workers. These are temporary; they will be removed when the airport is finished.

　　The airport, though, is here to stay. To protect it, the new coastline is being bolstered with a formidable twelve kilometres of sea defenses. The brunt of a typhoon will be deflected by the neighbouring island of Lantau; the sea walls should guard against the rest. Gentler but more persistent bad weatherthe downpours of the summer monsoonis also being taken into account. A mat-like material called geo-textile is being laid across the island to separate the rock and sand layers. That will stop sand particles from being washed into the rock voids, and so causing further settlement. The island is being built never to be sunk.