Abstract: The seabed at the construction site of jack-up often consists of highly layered soil. When encountering a hard layer overlying a soft layer, the rapid settlement of the legs can cause structural damage to the platform. This paper reviews the current methods for predicting spudcan punch-through capacity in multi-layered soils including sand-over-clay, stiff-over-soft clays, clay-sand-clay, sand-clay-sand, soft-stiff-soft clays and multi-layer soil with 3 or more layers. Back analysis is conducted by comparing the performance of these methods and field data in the eastern Guangdong sea area to accumulate experience, summarize the limitations of the methods and highlight the future research focus.

Key words: jack-up rig, multi-layer soils, spudcan, punch-through, case study