SIMULATION of SPUDCAN PENETRATION BEHAVIOUR in TWO-LAYER CLAY USING COUPLED EULERIAN LAGRANGIAN APPROACH

Jack-ups operate in various seabed conditions during their life cycle. In some cases, seabed comprises of stiff or dense soil layer overlaying soft or loose soil layer, thus it isprobable that the jack-up’s footing (so-called ‘spudcan’) encounters a sudden large displacement such as ‘punchthrough failure’ or ‘rapid leg run’, especially duringinstallation phase. Craig and Chua [1] and Teh et al [5] have carried out several centrifugal tests to survey spudcan penetration behavior during installation. Qiu and Henke [2] and Yu et al [3] have carried out numerical simulation to study spudcan penetration in soil. Classic Lagrangian approach cannot simulate large displacement problem due to mesh distortion problems, but there are some type of numerical simulation approaches that have an ability to simulate large deformation, such as RITTSS, ALE, CEL. In this study Coupled Eulerian Lagrangian (CEL) approach available in Abaqus–Explicit were conducted to simulate the penetration responses of spudcan in stiff clay overlaying soft clays. The punchthrough failure of spudcans on layered clays has been surveyed numerically. The effects of roughness, upper layer to lower layer strength ratio, upper to lower layer thickness ratio, spudcan apex angle have been studied. Bearing stress-displacement profile is illustrated to express the spudcan capacityresponse against the penetration depth. Punch through failure and its prerequisite conditions have been described.