Research and Application of Geotechnical Data Consistency in Marine Site Exploration

[Introduction] The current marine geological exploration, particularly the geotechnical investigation, often follows traditional experiences without a clear objective, and lacks the evaluations of soil sample disturbance and test results. Therefore, it is necessary to conduct in-depth research on marine geotechnical investigation technology. [Method] Based on the domestic and international research on marine geological exploration technology and multi-year working experience in different sea areas, we developed a new accurate marine geological exploration technology with emphasis on the principle of consistency. The geotechnical investigation part of the new method included two basic aspects: (1) comprehensive evaluation of soil sample disturbance; (2) comprehensive evaluation of consistency of soil strength test results. [Result] The three-dimensional cross-consistency analysis of geotechnical, geophysical, and geological models has established an accurate geological exploration system. Several examples of marine engineering projects showed that the new technology can screen good acquisition methods and data through comprehensive evaluation of clay soil sample disturbance, and conduct consistency analysis of various data by combining the laboratory geotechnical tests with in-situ tests and the routine geotechnical tests with advanced geotechnical tests to obtain richer and more continuous data at the borehole. Compared with the traditional single geotechnical test, our new technology demonstrated the improved reliability and accuracy of the data, and the missing data between the sampling points are compensated. [Conclusion] The proposed new method can reinforce the application of geological exploration data, reduce investigation costs, and provide more geotechnical parameters that are more reliable for marine engineering projects including offshore wind power.