Soil Plugging Mechanism on Large Diameter Pipe Piles: Insight from Discrete Element Simulations

Abstract

Large open-ended pipe piles are widely used in offshore foundations. These piles, when properly constructed, offer superior load carrying capability compared to traditional ones. As they can be driven into the ground, there is no need to construct a cofferdam as required for smaller piles in a river or a lake. The savings in the construction cost and schedule can be substantial. The use of large open-ended pipe piles in the transportation project at a few States produced satisfactory results. As most experience with large diameter pipe piles are gained in the offshore industry, the existing knowledge on this type of foundation is rather limited. Formation of soil plug is very important for the bearing capacity of this type of foundation to be mobilized. This paper performed DEM simulations to study the soil plugging mechanism inside the large diameter pipe piles. The advantage of DEM is that it can holistically simulate the interactions between soil particles as well as between soil particles and pipe pile. The results are compared against that predicted by analytical model. A sensitivity study was performed on the effects of factors such as soil column length, pile internal diameter, particle size, friction coefficient of interface between soil and pile, etc. These offers insight on the formation mechanisms of soil plugs inside the large diameter pipe piles.