Spudcan Deep Penetration in Multi-Layered Soils Incorporating Sand Relative Density

Abstract

Installing a spudcan jack-up rig in sediments with an interbedded sand-over-clay soil profile is still challenging in the offshore industry due to possible punch-through failure. The current methods for predicting the punch-through of spudcan usually ignore sand relative density, which is one of the most important parameters for sand soil. For multi-layered soils with interbedded sand commonly met in the field, this paper aims to determine the effects of sand relative density on predicting the punch-through failure of spudcan. Modified Mohr-Coulomb (MMC) and extended Tresca models characterized by incorporating a variation of mobilized strength parameters were used to describe the mechanical behaviors of sand and clay. Besides four groups of centrifuge tests, one field case in the South China Sea was also numerically simulated to validate the large deformation finite element (LDFE) analyses conducted in this paper. The results showed that neglect of sand relative density may lead to underestimation of the potential for punch-through failure of spudcan.

Keywords

• jack-up rig
• spudcan
• bearing capacity
• punch-through
• relative density of sand