Specifications for offshore platform engineering geology investigation.

Abstract

Offshore wind farms offer many benefits over traditional energy sources and are expected to contribute significantly to a reduction in climate change in coming years. Many countries have made commitments to reduce their carbon emissions and are therefore planning to expand their current renewable energy sectors. The use of this “renewable” resource to generate electricity, through the development of offshore windfarms, is recognized as one of the key elements in meeting the commitment to reducing greenhouse gases, and is supported by a number of global conservation organizations, including Greenpeace, the World Wide Fund for Nature and Friends of the Earth. The seabed is gentle flat, water depth is shallow and wind resources are abundant in the Yellow sea, which are suitable for construction of wind farm. A total of 50 wind turbines with 4.0 MW single unit capacity and 200 MW total installed capacity are designed and installed in this project. The wind turbines are arranged along the boundary of the wind farm, the spacing between East and West is 470-1850m, and the spacing between North and south is 620-1600 m. A 220 kV offshore booster station is set up to the west of the middle of the wind farm. All the power generated by the wind turbines can be boosted by 220 kV offshore booster station and connected to the landing point of the submarine cable by three 1 x 500 220 kV single core XLPE submarine cables in one circuit. The length of the 220 kV submarine cable route is about 31.8 km. Survey contents include Bathymetric and topographic survey, seabed conditions, shallow geology, soil physical and mechanical properties, corrosive environmental parameters, marine hydrographic and meteorological elements and so on. Equipment and sensors, such as side scan sonar, sub-bottom profiler, multi-channel seismic equipment, magnetometer, sampler and CPT were employed in this survey. This survey finished 1500km geophysical survey lines, 50 stations of drilling, 55 stations of in-situ test, and 12 stations of marine hydrographic observation within 120 days. This work was completed under the guidance of the national standards of the People's Republic of China (GB/T 17503-2009) "Specifications for offshore platform engineering geology investigation ".