Study on Mechanical Performance of New Modular Main Transformer Raft Foundation for Substation

To improve the quality and efficiency of substation foundation construction in medium and high altitude areas while reducing costs, this paper proposes a prefabricated modular raft foundation for main transformers in substations. The foundation is composed of small precast foundation units connected by bolts, aiming to realize modularization and rapid construction. Based on the main transformer foundation of a substation project, a prefabricated modular raft foundation is designed, and its mechanical performance and deformation characteristics under various working conditions are analyzed by finite element method. Furthermore, parametric analysis is conducted to investigate the effects of bolt diameter, connection hole size and section height. The results show that the structural stress is within the elastic range of the material under both normal and eccentric working conditions. The foundation settlement is uniform, and the maximum settlement and differential settlement are both less than the code limits. Structural failure initiates from concrete cracking at the bolted joints, followed by shear failure of the bottom slab on both sides of the pier. Bolt diameter has a slight effect on the ultimate bearing capacity, but can effectively enhance joint stiffness and significantly reduce the differential settlement of the foundation. Reducing the hole size and increasing the section height can improve the bearing capacity.