Research on the Engineering Geological Model and Its Application for Offshore Wind Power Development and Construction

[Introduction] Speeding up the offshore wind power construction and development is of great significance to promoting the adjustment of China's energy structure. China is accelerating the process of its wind power development in the entire offshore area, and the geological survey is a vital foundation and key technology of offshore wind power development. [Method] By studying the marine geological survey technologies at home and abroad and combining years of experience in different sea areas, this paper proposed a new technology of engineering geological modeling for offshore wind power development based on the principle of consistency. Firstly, the survey equipment selection and survey line layout started from a three-dimensional initial model to evaluate the impact of geological changes and geohazards on the offshore wind power engineering construction and took into full account the ship selection, field in situ and laboratory tests, and correlation of geophysical prospecting and geotechnical data. Then, with abundant and continuous data obtained from the boreholes and the whole wind farm during the feasibility study and detailed survey, the methods of combination of indoor geotechnical tests with the in-situ tests, the combination of multiple geophysical prospecting devices and the combination of geotechnical and geophysical prospecting methods were used to conduct a consistency analysis of various data, manage the geological survey data platform, update the model and build the final model, and the engineering geological model was continuously optimized and iterated in the subsequent stages. The engineering geological model provided comprehensive engineering geological information for the entire life cycle of offshore wind farm design, installation, operation, maintenance and decommissioning. [Result] The research results and offshore wind power geological survey examples show that by conducting consistent comprehensive layout and data analysis, effectively connecting geotechnical investigation with engineering geophysical prospecting and constructing a three-dimensional crossing engineering geological model, it can effectively solve the problem of "ambiguities of geological survey data" and improve the reliability, accuracy and application of geological survey data. [Conclusion] The new method proposed is one of the effective methods to reduce cost and increase efficiency in offshore engineering as well as the embryonic form of digital twin of offshore wind power geological survey and the foundation for the construction of a geological survey big data base.