Experimental, Numerical, and Analytical Studies of the Uplift Behavior of Mini‐Piles in Moistened Loess Foundations With Parameter Sensitivity Analysis

Mini‐piles are increasingly employed as foundations for transmission towers owing to their ease of construction and high uplift capacity. In loess regions traversed by transmission lines, however, systematic research on uplift performance remains limited, often leading to inadequate design, particularly under moistened soil conditions. This study investigates the uplift behavior of the pile–soil system in loess through a combined program of laboratory testing, numerical simulation, and analytical modeling. Geotechnical and water immersion tests were first carried out to determine the mechanical properties at varying water contents. Uplift load tests on mini‐piles embedded in both unsaturated and saturated loess were then conducted to evaluate their ultimate bearing capacities. A finite element (FE) model was subsequently developed and validated against the experimental results, enabling detailed analysis of load–displacement response, mechanical behavior, and failure mechanisms of the pile–soil system. Sensitivity analysis (SA) were further conducted to quantify the significance of key soil and pile. On this basis, an improved analytical model was proposed for predicting the uplift capacity of piles in diverse soils, demonstrating higher accuracy than conventional approaches. The findings provide new insight into the uplift mechanism of pile foundations in collapsible loess and offer practical guidance for the safe and efficient design of transmission tower foundations in similar geotechnical settings.