Abstract: Based on the existing measured data, the calculation precision of earth cone method and shear method for calculating the ultimate uplift capacity of the spread foundation in sand recommended in “Technical Code for Foundation Design of Overhead Transmission Line” (DL/T 52192014) was evaluated in this paper. It is shown that the values of critical depth defined in the two methods are too small. A correspondent improvement against the critical depth was therefore given based on the previous studies. The values of ultimate uplift capacity obtained from the modified earth cone method and the modified shear method were all greater than those of the uncorrected results. The calculated results agreed well with the measured results. In addition, from the point of the degree of coincidence and safety design, the modified earth cone method is preferable.

Key words: Slab Column Foundation, Sandy Soils, Uplift capacity, Critical Depth