Designing Reinforced Soil Structures

Q: Why is strain compatibility important in designing reinforced soil walls? 

A: When designing reinforced earth structures, a vital aspect is the interaction between the reinforcement and the compacted soil, as this governs the overall stability of the structure. The main function of the reinforcement is to redistribute the stresses within the soil structure to enhance the internal stability of the reinforced soil structure. The reinforcement undergoes tensile strain as it transfers loads from unstable to stable zones of the soil. In designing reinforced soil walls, strain compatibility of the geogrid to the surrounding soil is critical. If the geogrid is not matched (via a pullout test, i.e., ASTM D6706) to the soil in which it is embedded, it will not function optimally. One usually wants a geogrid to pick up load rapidly when strained, thus allowing minimal displacement.