Geotechnical Behavior of Conical and Skirted Foundations Through Experimental and Numerical Assessment

The present research has focused on the load–displacement relationship (P-δ) of flat and different types of shell foundations and the effects of various parameters including soil properties and foundation geometry have been considered.

The geotechnical behavior and influential factors (D/B, B, Dr, ϕ) of conical and skirted shell foundations have been studied via physical models and finite element method (FEM). The final outcomes have been verified through comparisons of loading behavior with other researches.

Increasing embedment depth ratio results in a growth in foundation capacity on different sand states specifically in weak sand layers with low relative density and angle of internal friction. The results of bearing load in loose sand demonstrated that conical shells with different D/B ratios have a higher bearing capacity than the skirted ones which is more highlighted in D/B ≤ 0.5. Nevertheless, by increasing sand density and enhancing soil shear strength, skirted foundation becomes more efficient compared to the conical, particularly for D/B ≥ 0.5. However, in both types of shells on dense sand, the general shear mode governs the foundation failure.

In this paper, the load bearing behavior and failure mechanism of shell foundations ((D/B = 0, 25, 0.5, 0.75) on loose and dense sand state (Dr = 29 and 73%) have been examined and compared to their flat counterparts. Enhancement in ultimate load by utilizing shell foundations and increasing the foundation embedment depth varies in a range of 34–100% depending upon foundation type, D/B, Dr, and angle of internal friction (φ).