COMPARING THE PERFORMANCE OF HELICAL ANCHORS AND DIRECT-EMBEDDED PLATE ANCHORS IN COHESIONLESS SOIL FOR TOP-DOWN RETAINING WALLS STABILIZATION: AN EXPERIMENTAL STUDY

Abstract

Mechanical reinforcements such as helical anchors, plate anchors, and direct-embedded plate anchors are implemented to stabilize different permanent and temporary retaining walls such as excavations and reinforced earth walls without grouting. Today, these anchors are widely used because of their high operation speed and the possibility of post-tension immediately after installation. In the present study, the performance of two common types of mechanical anchors, namely the helical anchor and direct-embedded plate anchors, is analyzed in the stabilization of retaining walls using physical modeling. In addition, the parameters including the number of the helices, shape and dimensions of anchor plates, and installation configuration of reinforcement are evaluated. The horizontal wall displacement was recorded by dial gauges installed in front of the facing and the critical slip surfaces of the mechanically stabilized earth walls or failure wedge were identified using Particle Image Velocimetry (PIV). Increasing the number of the screws in helical anchors from 1 to 2 and changing the circular and square plates from small to medium size led to a 60% increase in bearing stress of the strip footing. In comparison, increasing the number of screws from 2 to 3 and changing the circular and square plate anchors from medium to big size resulted in only 29% increase in the bearing stress. Although the number of reinforcements is equal in both diamond and square configurations, the diamond configuration showed considerably higher performance in controlling the displacement of wall crest than the square configuration.