Geosynthetic polymeric material Reinforced Model Shallow Foundation's Monotonic and Cyclic Uplift Response Affected by Ground Inclination

Abstract

The foundation system of any structure is vital for ensuring safety, serviceability, and performance, particularly when subjected to vertical and uplift forces. While conventional foundations are primarily designed to resist compressive loads, structures such as transmission towers, offshore platforms, buried pipelines, retaining systems, and marine facilities are frequently subjected to uplift forces generated by wind, waves, buoyancy, and cyclic loading. Under such conditions, the uplift resistance of soil and uplift capacity of shallow foundations become considerations for foundation design.

The present study investigates the effect of ground inclination on the monotonic uplift capacity of shallow foundations with and without geotextile reinforcement. Laboratory model tests were conducted to evaluate the uplift behaviour of shallow footings under various ground inclinations of 0°, 20°, 30°, and 40°. The experiments were performed at relative compaction levels corresponding to 60%, 70%, and 80% of the maximum dry density (MDD). The performance of unreinforced and geotextile-reinforced foundations was comparatively assessed under monotonic uplift loading. In addition, the influence of different ground conditions, namely dry, optimum moisture content (OMC), and submerged conditions, was investigated to understand the effects of moisture and saturation on uplift resistance.

Furthermore, cyclic uplift loading was applied at 50% of the ultimate monotonic uplift stress to examine the foundation response and failure behaviour under repeated loading. The influence of cyclic loading was evaluated for all three ground conditions. The experimental results were analysed to establish relationships among ground inclination, soil density, reinforcement, moisture condition, and uplift capacity. Based on the experimental data, polynomial regression analysis was also carried out to develop predictive equations for estimating uplift capacity under different testing conditions. The findings provide useful insights into the behaviour and design of shallow foundations subjected to uplift forces on inclined and geotextile-reinforced ground, and support foundation design under monotonic and cyclic loading conditions.