Abstract: Metal grillage foundations are increasingly used in infrastructure of transmission line in aeolian sand areas because of its convenient construction and relatively low cost. The full-model and half-model uplift tests under the influence of embedment ratio were carried out in foundation of medium dense aeolian sand, and the uplift load-displacement properties and uplift failure mode of the foundation under different embedment ratios were studied as well. The results show that the uplift load-displacement curve relates to the embedment ratio ?: when ? is 1.0, the curve varies gradually; while ? is in the range of 2.0?5.0, the curve shows clear strain softening with a peak load. As the ? increases, the uplift capacity increases accordingly. During the loading process, an approximately circular uplift area centered on the top of the foundation developed on the ground surface gradually, the uplift degree increased as the foundation was pulled up, and finally formed an overall failure, along with the sliding surface penetrating the ground. In the half-model tests, meridians of the sliding surfaces were observable, which can be approximately described by linear equation as the uplift angle decreased with the increase of the embedment ratio. According to the above results, based on Veesaert’s sliding surface friction strength theory and the limit equilibrium principle, an improved calculation method for uplift capacity of metal grillage foundation has been proposed. Compared with the earth cone method and the shear method, the improved method can obtain calculation results closer to the experimental values with smaller dispersion.

Key words: uplift capacity, metal grillage foundation, medium dense aeolian sand, model test