Liquefaction analysis of a transmission tower site during the 2023 Ms6.2 Jishishan earthquake

This study analyzes the effect of a transmission tower on earthquake-induced soil liquefaction through three-dimensional numerical simulation of the Cao Tan Village site during the 2023 Ms6.2 Jishishan earthquake. The P2PSand constitutive model implemented in FLAC3D, which can effectively represent stiffness degradation and pore pressure buildup of sand under cyclic loading, was adopted to simulate the soil behavior. Synthetic seismic waves with a peak ground acceleration of 3 m/s 2 were applied as dynamic input. The results show that the presence of the tower significantly modifies the liquefaction process in a depth-dependent manner. The vertical tower load increases confinement near the ground surface (0-1 m), reducing liquefaction potential (surface effective stress maintained at approximately –2.2×10 5 Pa), while it promotes pore pressure accumulation and cyclic softening within the 5-20 m sandy silt layer, where the effective stress decreases to nearly zero. This bidirectional effect, caused by stress redistribution, indicates that structural loads can intensify liquefaction susceptibility at middle depths. The established numerical workflow successfully reproduces this complex three-dimensional interaction and provides valuable guidance for the seismic safety assessment and design of critical infrastructure in loess-covered regions.