Computational methods for uplift capacity of belled piles

A reasonable formula for calculating the uplift capacity of belled piles is proposed for both cases of homogeneous and stratified foundations. It is assumed that the slippage failure surface consists of the cylindrical surface and the exponential curved surface. The formula is deduced by using the limit equilibrium methods. Moreover, its numerical integration is carried out through Matlab. Engineering examples are employed to verify the proposed formula. The results agree with the actual ones very well.