Recently plug heave (soil rising within open ended tubular piles) phenomena caused, sometimes unexpected, problems in offshore developments. While some had relevant field experience concerning these effects and were prepared to deal with them, others were not forewarned and experienced the consequences at their cost. Surprisingly it turned out that, apart from suction installed piles, the plug heave phenomenon is not mentioned in recommended practices or industry standards, neither is it a topic in research literature. This paper is a first step to remedy this. Plug heave in long slender piles, where plug heave would not be expected up front by many, is discussed. The difference between static and dynamic installation conditions is shown to be an essential factor contributing to the development of plug heave in these piles. Finally, the use of pile installation templates is demonstrated to have a potential effect on (initial) plug heave. While accurate prediction of plug heave is shown to remain a challenge, providing insight in the mechanisms is easier. This insight is believed to be essential to create awareness and ensure that contractors and designers are not caught by surprise.
Dirk Luger and René Thijssen
Keywords: plug heave, plugging, soil rise, pile installation
Publisher: DFI