ABSTRACT

The spudcan will be penetrated into the sea bed to supply enough bearing capacity when a mobile jackup operates near the jacket platform. The effects of the spudcan penetration on the pile foundation of the platform should be assessed if the distance between the spudcan and the pile is less than 1.0 time the diameter of the spudcan based on SNAME Code (2002). The Coupled Eulerian-Lagrangian finite element analysis and the nonlinear foundation beam analysis are combined to analyze the effects of the spudcan penetration on the pile group of the jacket platform for the engineering case of China South Sea in this paper. The main conclusions are as follows:

  1. The penetration- induced lateral soil load does not result in notable displacement of the affected pile group head due to the support of other pile groups. But the load can result in larger lateral deflection of the pile group below the sea bed. The lateral deflection of the pile group increases with the increase of spudcan penetration and finally tends to be stable when the penetration depth exceeds a certain depth. The depth of the maximum lateral deflection increases with the increase of spudcan penetration.

  2. The direction of the total lateral deflection is not the direction connecting the center of the spudcan to the center of affected plies.

  3. The moment and the shear force of the pile group increase with the increase of spudcan penetration.

  4. Compared with the pile group only subjected to lateral pile-head load' the lateral deflection of the pile group notably increases under combinations of the lateral pile-head load and the penetration-induced load.

  5. Compared with the response of pile group subjected to the lateral pile-head load' the variation of the bending moment in the range of 0.56 times diameter of spudcan below the seabed is not obvious and the maximum pile bending moment increase 24% below the depthunder the combinations of loads.

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