INITIAL GEOTECHNICAL STUDY
According to the initial geotechnical study, in order to determine the stratigraphy of the sea bottom in the area, 8 drillings were performed with the use of a floating, self-elevating platform, which led to the following conclusions:
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Throughout the area of works, there is a dominant non-cohesive sandy layer, of small to mean thickness, which emerges from the natural sea bottom up to approximately 15 meters in depth.
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A weathered and stripped rock underlies the sandy layer, but in one particular drilling, in the area of the planned bridge connecting the port with the coast, the rocky layer appeared 4 meters under the sea bottom.
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The main characteristic of the sandy layer is the looseness it presents at its upper layers, which results in the possible formation of liquefiable zones in case of an earthquake.
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The potential liquefiable zone extends to 7.0 m under the sea bottom in the area of the passenger terminal, whereas in the area of the marina, the vitiation zone extends only down to 2.5 meters.
The solutions that were initially proposed were the following:
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In the area of the marina, it suffices to remove the upper 2.5 meters of sand and replace them with a single layer under 1.50-m thick ballast, and then with an upper 1.00-meter thick layer.
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In the area of the passenger terminal, it is necessary to radically improve the foundation conditions through the application of the deep vibro compacted method
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The proposed cross section provided for the excavation of the natural ground down to -17 m and its replacement with riprap.
