Experimental and analytical evaluation of enhanced interface efficiency with geocell anchor cages

A new reinforcement concept of Geocell Anchor Cage (GAC) system has been recently proposed by the authors and its benefits in increasing the load carrying capacity and reducing the settlements are established. This paper evaluates the interface shear response of geocell-GACs in comparison to geocells and geocell-grid combinations through large direct shear tests. Results showed that the sand-geocell-GAC interface has shown an increased interface efficiency of 1.5 compared to an interface efficiency of 1.25 computed for the sand-geocell interface at a normal stress of 25 kPa. This difference is slightly reduced at higher normal stresses, but the GACs constantly showed higher interface efficiency compared to geocell and geocell-grid interfaces with sand. Further, interface shear tests were carried out with different geocell pocket sizes to confirm the beneficial effects of GACs and to understand the influence of relative size of geocells and anchor pins. The individual contributions of geocell, geogrid and pins in increasing the interface shear resistance are analytically quantified. Through Particle Image Velocimetry (PIV) analysis of videos captured during shear tests, particle movement and shear zone formations are compared to provide clues to the internal shear mechanisms and interactions involved. • New class of geocell reinforcement with geocell anchor cage (GAC). • Interface shear tests to quantify the effectiveness of geocell-GAC over conventional forms of geocell reinforcement. • Particle Image Velocimetry (PIV) analysis to understand the interface shear mechanisms in various reinforced systems. • Analytical equation to compute the individual contributions of geocell, grid and pins to the overall passive resistance in a geocell-GAC system. • Validating the equation for different geocell pocket sizes.