Written By: Michael J. Dickey, P.E., Samantha Justice, P.E., Bryan Wedin, P.E. When constructing roadways over soft soils and weak subgrades, geocells are one of the most powerful value engineering tools available to the civil engineering and construction industries today. Understandably, some engineers may be apprehensive about using a geosynthetic product for which they have an incomplete technical understanding. So, if you’ve ever wondered how geocells work in load support applications – and the relationship between lateral confinement and hoop stress – you’ve come to the right place. Generally speaking, geocells can be used to alter the geometry of a soil pressure bulb beneath an applied load through a phenomenon known as the mattress effect. Key to the mattress effect is a physical mechanism unique to geocells known as lateral confinement. When a load is applied to a geocell-reinforced layer, lateral earth pressures develop within the infill material, which is confined laterally by the cell walls against movement, in turn developing upward shear resistance along wall interfaces throughout the interconnected network of cells. In essence, lateral confinement converts horizontal earth pressures into upward resisting shear forces.     When combined with suitable base reinforcement (i.e., an enhanced woven geotextile), it… Read more »