Behavior of Large Diameter Bored Piles in Calcareous Cemented Sand in Kuwait-Paper

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The paper evaluates large-diameter bored piles (0.6–1.5 m) in Kuwait’s calcareous cemented sand and assesses whether numerical modeling can support more reliable foundation design than empirical correlations developed for other sands.<br /><br />The soil is nonlinear and stress-dependent: stiffness generally increases with depth, is higher during unloading/reloading than primary loading, and varies with density and cementation. Field observations suggest its behavior is largely drained. Reported pile skin friction ranges from about 45 to 100 kPa; a case study estimated average skin friction of 80 kPa and base resistance of 3.5 MPa.<br /><br />The authors derived preliminary soil parameters from published laboratory and field studies, compared Mohr–Coulomb (M-C) and Hardening Soil (H-S) models against drained triaxial tests, and used Plaxis 3D to analyze an 800 mm diameter, 22 m long test pile. The pile reached 73 mm settlement, approximately 10% of its diameter, at a measured load of 10,000 kN. Preliminary H-S parameters were then refined to better match the load-test response.<br /><br />The H-S model reproduced the soil’s nonlinear stress–strain behavior and pile response reasonably well, especially at early loading and near yield. The simpler M-C model was limited in representing pre-failure behavior because it assumes a linear response. Refined H-S parameters matched measured pile behavior up to approximately 6,000 kN, but the model underestimated capacity at higher loads. The authors suggest this discrepancy may relate to differences between modeled and actual initial stresses; increasing the modeled earth pressure coefficient increased predicted capacity.<br /><br />The study concludes that H-S modeling can support analysis of bored piles in Kuwait’s cemented sands, but site-specific calibration is essential before applying single-pile test results to foundation design. Further laboratory and field testing, including instrumented pile tests, is recommended to address modeling assumptions and limitations.

Keywords

bored piles

calcareous sand

Kuwait

numerical modeling

Hardening Soil model

Mohr-Coulomb model

Plaxis 3D

pile load test

skin friction

foundation design