Laboratory Testing Apparatus for Slopes Stabilized by Anchored Geosynthetics
A laboratory testing apparatus is described for examining slopes subjected to seepage and stabilized by anchored geosynthetics (AGS). The AGS technique can increase the stability of cohesionless slopes such as coastal dunes against surficial erosion and shallow mass failure caused by wave action and seepage forces. In the AGS, a geosynthetic fabric is placed on the face of the slope and tensioned via anchorage to the ground. The required tension is achieved through frictional or pullout resistance of earth anchors that are fastened to the fabric and driven into the underlying soil mass. In the laboratory testing apparatus, however, AGS tensioning is provided by thin wires connected to rigid steel tubes that exert line loads on the fabric. The wires in turn are connected to dead weights “beneath” the slope that simulate anchor loads. The prototype slopes are failed by uniformly decreasing anchor loads while maintaining the seepage gradient and orientation constant. Very good agreement was observed between experimental results and theoretical predictions of the failure mode and the average AGS loads at failure.