Design of Geomembrane Anchorage Against Wind Action

Abstract

This paper provides a method for designing anchor benches and trenches used to secure geomembranes exposed to wind action. Only the cases where anchorage is provided by gravity (i.e. by the weight of the material in the bench or trench) are considered. Anchorage by tensile members is not considered. Three potential failure mechanisms are identified for the case of anchor benches: (i) sliding of the anchor bench in the downslope direction; (ii) sliding of the anchor bench in the upslope direction; and (iii) uplifting of the anchor bench. It is shown that the first mechanism is the most likely and that the third mechanism is the least likely. Criteria are provided to determine the governing potential failure mechanism as a function of the geometry of the slope on which the geomembrane is resting and the geomembrane tensions induced by wind action. Equations are provided to calculate the required size of anchor benches for each of the three identified potential failure mechanisms. It is shown that the usual method, which consists of only checking the resistance of anchor benches against uplifting, is unconservative because, in the case of anchor benches, lateral sliding is more likely to occur than uplifting. The use of the proposed method as a conservative approach for the design of anchor trenches is discussed. Practical recommendations are made and design examples are provided.