As transmission line projects continue to expand into the western mountainous regions of China

the need for more transmission tower foundations on steep hillsides has increased. However

research on the uplift bearing deformation characteristics of pile foundations under high-intensity wind and snow scenarios on sloped ground is lacking

and current specifications are insufficient. Therefore

laboratory model tests were conducted on rock-socketed uplift piles on both flat and sloped ground to investigate load-displacement curves

ground deformation and crack propagation

failure mode

axial force of pile

side friction of pile

and relative displacement between the pile and rock. ABAQUS numerical simulation results were compared to the model test results to validate the reliability of the numerical model and investigate the influence of steepness (slope angle) on the bearing capacity and deformation characteristics of rock-socketed uplift piles. The results demonstrate that the load-displacement curves for flat and sloped ground have similar steep shapes

and sloped ground can have an adverse impact on the bearing capacity and deformation characteristics of rock-socketed uplift piles. The decrease in pile bearing capacity is positively correlated to the steepness of the slope

with a decrease of 0%–12.8% for slopes of 0º–30º and up to 25.9% for a slope of 45º. Bedrock failure surfaces mainly occur in the downhill slope within a range of 3.2d(d is pile diameter)

as well as within a fan-shaped range of 120º

while the failure range on adverse slopes is about 1d

which is different from symmetrical and composite failure on flat ground. When the load on the top of the pile reaches approximately 80% of its ultimate bearing capacity

visible cracks can be observed in flat or downhill areas of sloped ground. These research findings offer a scientific basis for improving the design and specifications of uplift resistance capacity in transmission tower foundations on sloped ground.