Dynamic behavior of geogrid reinforced segmental block walls under earthquake loads
The results of an experimental study conducted on two 1/2 reduced-scale geogrid-reinforced soil retaining block walls are presented and discussed. The heights of the models were 1.9 m and El Centro, Izmit and Sakarya earthquakes were applied. The prototype design was taken from a design made for a real project. Therefore the geogrid reinforcement and facing blocks were scaled versions of the real wall. The geogrids are connected to the facing blocks only by friction. Again to simulate the real design, the walls were constructed with 6° inclined facings. Two different backfill materials were used. In the first model coarse grained gravel and in the second model well graded sand was used and their effects on the measured parameters are investigated. The aim was also to see whether the wall designed according to current specifications would behave as it was designed under an earthquake loading condition. Accelerations, strains in the reinforcement layers and facing wall deformations were registered for a later complete evaluation. The test results showed that in both experiments the walls in fact behave almost elastically and the residual displacements observed on the front of the wall were very small under the design earthquake accelerations. The first most important conclusion drawn from the experimental work is that the designed Geosynthetic Reinforced Retaining Structures behaved very successfully under earthquake loading conditions. However it was determined that the backfill type has an effect on the behavior of the wall.
The geogrid reinforced segmental block walls designed according to current specifications showed a very good resistance to earthquake loading conditions. They remained stable even under extreme lateral accelerations. Both gravel and sand backfill showed very successful behavior. No stability problem occurred even under extreme lateral accelerations. The Geogrid Reinforced Segmental Block Walls showed minimal residual deformations and acceptable maximum deformations under extreme lateral earthquake accelerations.