Abstract: To address the construction requirements of heavy-load transmission line foundations in loess regions, this study proposes a novel composite foundation configuration consisting of an upper short column and multiple lower batter piles. A validated numerical simulation method, supported by experimental results, was employed to optimize structural configurations of various composite forms and analyze their load-bearing mechanisms. Through orthogonal experimental design, the influence ranking of the quantity, length, and inclination angle of inclined piles on bearing capacity was systematically clarified. Under equivalent volume conditions, increasing the embedment depth of the short column while appropriately reducing the length of inclined piles was found to enhance uplift bearing capacity without significantly compromising compressive capacity. Based on extensive numerical simulations, preliminary recommendations for the structural dimensions of the composite foundation were proposed. During upward loading, the short column reaches ultimate capacity first; during downward loading, the inclined piles reach ultimate capacity first. The bearing capacities of the short column and inclined piles are asynchronous across different loading conditions. A calculation methodology incorporating bearing capacity mobilization coefficients was developed for short column-inclined pile composite foundations, providing valuable references for related foundation designs.

Key words: loess, transmission line, composite foundation, bearing capacity, bearing mechanism