On spudcan deep penetration using Eulerian finite element in multi-layer sediments: soil plug mechanism

摘要

In stratified deposits, where an interbedded strong layer overlays a weak layer, the punch-through failure may occur and a soil plug from the overlying stronger layer usually exists beneath the advancing spudcan. Due to the limited understanding of the soil plug mechanism which really exists in both the strong-over-soft and soft-over-strong strata, no consideration of the soil plug effects is included in the present methods recommended in the current industry guidelines. This paper reports numerical simulations of spudcan deep penetration in multi-layer sediments with an interbedded sand layer, and aims at providing a better understanding of the soil plug mechanism. An extended Tresca model incorporating the clay strain softening together with an extended Mohr-Coulomb model with incorporation of the progressive failure of sand is used in this study. By comparing with the existing large deformation finite-element (FE) results and the centrifuge tests results, the numerical analyses conducted in this study are verified and discussed. Based on the soil plug mechanism, an improved approach, in which the sand plug mechanism is incorporated in terms of the three geometric parameters, h1, h2, and d1, is further presented for prediction of the spudcan penetration resistance.