The anchorage of geogrids in soil is designed, on the one hand, under the simplifying but arguable assumption of a constant interaction coefficient along the entire geogrid anchorage length. On the other hand, considerable and presumably positive effects caused by the deviations in a typical geogrid alignment are neglected. The existence of a multitude of safe structures designed this way might show that these two simplifications neutralize each other. However, as the pullout failure mode is actually decisive in anchorage trenches with low overburden, geogrid anchorage with trenches should be examined in more detail. In addition, with increasing requested service life durations up to 100 years, e.g., from German legislation, the required accuracy of the predicted material loading for all geogrid components increases as well. Therefore, a model for the interaction between geogrid and soil has been developed at RWTH Aachen University with more than 120 pullout tests, which explicitly takes into account both load transfer mechanisms (i.e., friction and mobilized earth pressure in front of transverse tensile members). Additionally, an approach to include deviation effects within anchorage trenches has been formulated, which has been incorporated into the interaction model. In this paper, the model development is presented as well as its successful validation, first, with results from large pullout tests for the interaction model and, second, with field measurements from within a geogrid anchorage trench for the deviation effect approach.
Menu