Spudcan Penetration in Sand-Over-Clay Considering Soil Variability-Paper

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This study examines punch-through failure of spudcan foundations penetrating a thin sand layer over soft clay, accounting for spatial variability in soil strength. The authors combine random-field modeling with the Coupled Eulerian–Lagrangian (CEL) finite-element method to simulate large deformation. Sand friction angle and clay cohesion are represented as spatially varying properties, and the numerical approach is validated against centrifuge-test results. Monte Carlo simulations cover 400 soil realizations.<br /><br />Punch-through occurs in all simulations. In a representative random soil profile, the mean peak penetration resistance is 6% lower than in uniform soil, and the punch-through distance is also slightly shorter. Failure surfaces in variable soils tend to follow weaker zones, unlike the symmetrical failure pattern found in uniform soil. The 400 simulations show that peak resistance is below the uniform-soil value in 73% of cases; peak depth and punch-through distance are lower in 70% and 69% of cases, respectively.<br /><br />The results indicate that assuming uniform soil may overestimate spudcan resistance and misrepresent failure mechanisms. Accounting for spatial variability is therefore important when assessing punch-through risk and foundation bearing capacity.

Keywords

spudcan foundations

punch-through failure

thin sand layer

soft clay

spatial variability

random-field modeling

coupled Eulerian-Lagrangian method

finite-element simulation

Monte Carlo simulations

bearing capacity