Abstract: To enhance the tensile performance of pile foundations, an inclined anchor-short pile foundation with an anchor plate was proposed for transmission lines in areas with overlying soil and underlying rock layers in mountainous regions. An indoor model test of a reinforced concrete short pile with three inclined anchor foundation joints was conducted to study the mechanical characteristics and failure mechanisms of these joints under multi-directional tension. The results show that the short pile and anchor bar work synergistically. The tensile crack first occurs at the joint of the anchor rod, then the vertical main crack extends to the pile top, leading to the overall splitting and failure of the specimen. The cracking load of the specimens is approximately 150 kN, the yield load is approximately 1 611 kN, and the ultimate load is approximately 1 845 kN. Before failure, all the anchor bolts yield, while the longitudinal bar and stirrup inside the pile do not yield, indicating stable anchoring performance of the inclined anchor. When the load on the inclined anchor-short pile foundation is small, the anchoring action between the pile and anchor is mainly borne by the bonding action of the straight anchor section of the steel bar. As the load increases, the anchoring effect is mainly borne by the bearing effect of the anchoring plate. The oblique stress between the anchor ribs combines with the corresponding oblique shear stress τ_α  in the short pile, causing the concrete cracks around the anchor bars to deflect and exacerbating the development of concrete cracks to the pile surface. This study provides a reference for the design of composite foundations and the study of deformation characteristics and failure mechanisms.

Key words: inclined anchor-short pile foundation, anchor plate, joint, stress characteristic, failure mechanism