Interacting Footings on Geo-Reinforced Soils: A State-of-the-Art Review

Soil reinforcement is increasingly applied in many geotechnical applications due to its high performance and justified costs than other alternatives. Footings are frequently located close to each other leading to interference with one another's efficiency. Closely constructed shallow footings on geo-reinforced soils (GRS) have a markedly significant effect on bearing capacity (BC) combined with more complex interaction behaviors than individual footings requiring further research. This research aims to investigate in more detail than hitherto done with attention paid to the BC, tilt and efficiency factors of interfering footings. The potential BC failure and resistance mechanisms are discussed in detail. Optimal reinforcement variables and new relationships are proposed for various footing geometries using new dimensionless interference factors to achieve more accurate analysis and design of twin footings on GRS. Based on shortcomings of the cited studies, design guidelines and future research recommendations are made. Results reveal that maximum interference factors of the interacting footings on GRS appear when the ratio of the center-to-center distance of footings to a footing width Δ/B is almost 1.5–2 depending on the footing geometry, underlying soil and reinforcement characteristics. However, at the range of Δ/B = 3–5 the interference factors disappear. Optimizing reinforcement parameters, the combined influence of reinforcement and interference led to increasing the magnitude of BC by 1.35 to 3.6 times. Reinforcement below interfering footings reduces the depth of influenced stress significantly.