Abstract: In offshore geotechnical engineering, accurately simulating large-deformation problems such as pipeline installation and spudcan installation is crucial. Conventional large-deformation approaches such as the Coupled Eulerian–Lagrangian (CEL) method are restricted by Abaqus, making effective-stress analysis impractical. Although the Remeshing and Interpolation Technique with Small Strain (RITSS) can overcome this limitation, its core variable-mapping procedure relies on self-developed interpolation algorithms, which impose a high entry barrier. To address this issue, this study develops two large-deformation finite element methods based on an improved superconvergent patch recovery (SPR) technique and an improved mesh-to-mesh solution mapping (MSM) technique, respectively. Using these methods, two representative cases—ball penetrometer penetration and spudcan installation—are investigated, and the results obtained from the two approaches are validated. The results show that, for the Ball penetrometer penetration problem, the normalized penetration resistances predicted by both methods agree well with centrifuge test data, with the improved MSM method yielding results closer to the experimental measurements, demonstrating the reliability of both approaches for this problem. However, for the more complex spudcan installation simulation, the improved MSM-based results exhibit pronounced fluctuations and errors, whereas the SPR-based RITSS method delivers higher accuracy and better stability. This study provides a practical technical route for effective-stress large-deformation analysis in engineering applications.

Key words: RITSS, effective stress, interpolation algorithms, ball penetrometer, spudcan