The spudcan will be penetrated into the sea bed to supply enough bearing capacity when a mobile jack-up operates near jacket platforms. Additional moments and shear forces along piles will be resulted from spudcan penetration and extraction. In order to understand effect of spudcan penetration and extraction on adjacent piles subjected to lateral and vertical pile head loads, model tests are conducted under 1g condition. Model test strata are the soft clay and the fine sand, respectively. The pile head constraint is free for model tests in the soft clay. The pile head constrain is elastic and free for model tests in the fine sand, respectively. Spudcan penetration resistances, pile bending moments, lateral displacements of pile head, lateral soil resistances along piles and lateral soil displacements are measured. Effects of lateral and vertical pile head loads, the pile head constraint on adjacent pile responses and lateral soil resistances along the pile are analyzed during spudcan penetration based on model test results. Residual responses of piles are also analyzed after spudcan extraction. These model test results are helpful for understanding the effect mechanism of spudcan penetration and extraction on adjacent piles.
The spudcan with large diameter will be penetrated into the seabed to supply sufficient bearing capacity for operations when a mobile jack-up is conducting drilling and fixing works in close proximity to a permanent jacket platform in offshore oil and gas development. Moreover, the penetration depth exceeds 1 time spudcan diameter in the soft seabed. Spudcan penetration and extraction will result in additional lateral loads on adjacent piles. The effects of spudcan penetration on pile foundations of the adjacent jacket platform should be evaluated if the distance from the spudcan edge to the edge of platform pile is less than 1.0 time the spudcan diameter based on SNAME (Society of Naval Architects and Marine Engineers) Code (2002). Some researches were conducted to understand effects of the spudcan penetration and extraction on adjacent platform piles.
