Numerical Study of Bearing Capacity of Circular Footings on Layered Soils with/without Skirted Sand Piles

The present paper investigates the behaviour of circular shallow footings on soft clayey soils with skirted and non-skirted sand piles. The main goal of this study is to evaluate the settlement and bearing capacity of a circular foundation, which is placed on a soft clay layer, based on a sandy soil layer. Different piles with varying length-to-clay layer thickness ratios ranging from 0.25 to 1 were modeled numerically, both with and without skirt. The effects of using a steel skirt and the length-to- clay layer thickness ratio of the piles, compared to case in which the footing is placed on a pile without any skirt, and in the case of a shallow foundation without piles, were also investigated in this study. A model generated by finite element software was used for numerical analysis. The results indicate that the use of skirted piles can affect the load settlement curves and increase the bearing capacity. By increasing the ratio of pile length-to-clay thickness, the bearing capacity of the shallow foundation will be increased and the corresponding settlement will be decreased. Therefore, the bearing capacity failure mechanism of a footing rested on soft clay can be modified from the punching failure to the general shear failure at the tip of the confined replaced sand column. Load settlement diagrams and ultimate bearing capacity obtained by numerical results are verified with similar experimental tests have been performed in the literature.

کلیدواژه ها:

Skirted pile ، Bearing capacity ، Circular footing ، Soft clayey Soil ، Numerical analysis.