A short way off the coastline of Dubai lie several remarkable islands in the shape of giant palm trees: Palm Jumeirah, Palm Jebel Ali, and Palm Deira, still under development. Each is comprised of peninsulas stretching from a trunk attached to the Dubai coastline, and topped further outward by a long seawall for shelter. It must have taken very many geotechnical consultants to make the necessary examinations of the site’s seabed, each geotechnical consultant a specialist in seabed engineering. Because creating an island out of shifting undersea sand will require a lot of engineering expertise even before anything can be put down on paper, prior to making any tangible construction.
The Palm Jumeirah Crescent or jetty is just 13 feet above the sea height at ebb tide, and ascends from 34 feet of water at its deepest point. Its engineers state that it is elevated enough not to sink in the going up of the sea level should global warming truly happen, or any tidal waves that might form in the Persian Gulf. The jetty is formed from rocks taken from the mountains. At its bottom is sand covered by a geo-textile or meshed fabric to inhibit the sand from flowing out. Weighing down this ‘wrapped’ sand is a stratum of one-ton boulders, over which two strata of six-ton rocks sit to form the top part.
The peninsulas extending from the central avenue are made also from sand taken from the seafloor and then vibro-compacted to support buildings. Palm Jumeirah was made from 3,257,212,970.389 cubic feet of sand. Vibro-compacting is performed by filling up the sand with water then shaking it via probes to make the sand settle more densely. First a probe is buried into the sand below the surface through water filling and vibration. As the probe sinks to its intended depth, loose sand is tossed down into the opening made by the vibrator probe. Thus a denser zone of sand is made, enough to hold up construction.
However, vibro-compaction may be appropriate only in clean sand where silt matter constitutes only 15% at the most.
In eery peninsula or frond are two lines of residential land or buildings for the awfully rich, and anyone can purchase his place there. Palm Jumeirah is expected to house 120,000 homeowners and workers, plus a different 20,000 tourists every day. So it is not truly a small island where solitude can be obtained, but a colossal self-sufficient sub-urban area of the truly, really billionaires. There are at present people living in the islands: real residents, transients, speculators and workers making last touches to some parts of the built up areas. A six-lane highway today functions as the transportation artery in and out the peninsulas, but in the last stages, residents will also be served by a rail transport system.
Palm Jumeirah and the three other man-made islands exemplify what contemporary engineering supported by a lot of money can accomplish. While land building from the sea to make islands may not be a new idea because it has been done numerous times before, the project’s massive size makes it so.
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