A Novel Approach for Evaluating Small-Strain Shear Modulus of Marine Soils Using Piezocone Penetration Test

Accurate determination of the small-strain shear modulus (<italic>G</italic>_max) of marine soils is essential for the seismic design and disaster assessment of marine engineering. This study conducted a series of piezocone penetration tests (CPTu) and resonant column tests on marine soils from two engineering sites in the East China Sea and the South China Sea. This research investigated the applicability of five common CPTu-based <italic>G</italic>_max evaluation methods. The investigation assessed these methods for coarse-grained soils, fine-grained soils, and all soil types collectively. Furthermore, this paper proposed a new <italic>G</italic>_max evaluation method. This new approach considers the differences in soil properties and soil fabric. The results reveal several key findings. Existing methods based on polynomials are more suitable for coarse-grained soils. Existing methods based on the pore pressure parameter ratio (<italic>B</italic>_q) are more suitable for fine-grained soils. Existing methods based on the SBTn soil classification chart are more suitable for evaluating all soil types simultaneously. Additionally, the proposed new method demonstrates improved accuracy compared to the five existing methods. Compared with the method that shows the best error control among the existing approaches, the error range is reduced by 17.8%. Finally, validation using existing literature data proved that this new method has good universal applicability.