Numerical analysis of instrumented mechanically stabilized gabion walls with large vertical reinforcement spacing

The paper describes numerical models that were developed to simulate the performance of two instrumented mechanically stabilized earth walls constructed in Izmir, Turkey. These walls were constructed with gabion facing, hybrid reinforcement layers, and fill on a rigid foundation. The hybrid reinforcement layers comprised primary reinforcement (geogrid) and secondary reinforcement (wire mesh). The vertical spacing between the primary reinforcement changed from 1 m to 2 m in two walls while other properties were kept the same. The responses of the field walls at the end of construction were simulated and compared with the numerical results. The results calculated from the numerical models showed generally good agreement with the measured wall facing displacements, horizontal fill displacements, and tensile forces in the geogrid and in the wire mesh. The maximum calculated facing displacements for the walls with 1 m and 2 m reinforcement spacing were 30.7 and 36.4 mm, respectively. The maximum tensile forces in the geogrid layers were increased by 1.5 times in the 2 m spacing wall as compared with the 1 m spacing wall due to the increase of primary reinforcement spacing. However, the spacing change did not have an obvious effect on the increase of tensile forces in the secondary reinforcement (the wire mesh). The calculated results were also compared with theoretical results relating to the earth pressure distributions and the location of the maximum tensile strains in the primary reinforcement. The horizontal earth pressures against the wall facing were close to the active earth pressures for both walls. The maximum tensile strain line of the reinforcement was close to the Rankine's failure line.