Large-scale shaking table tests on modular-block reinforced soil retaining walls

This paper presents an experimental study of the earthquake performance of modular-block reinforced soil retaining walls which were backfilled with sand using large-scale benchmark shaking table tests. The reinforcements used were polymeric geogrids, which were frictionally connected to the facing blocks having a front lip. In addition to observing the seismic performance, the purpose of testing was to generate quality data for future validation of numerical procedures. Three large-scale 2.8 m high modular-block geosynthetic-reinforced soil walls were subjected to significant shaking using the Kobe earthquake motions. Each wall was excited with a one-dimensional horizontal maximum acceleration of 0.4g followed by 0.86g. Vertical acceleration was superimposed on the horizontal one in the third wall. The walls were instrumented intensively using over 100 transducers to measure lateral and vertical earth pressures, wall facing displacement, crest settlement, reinforcement strains, and accelerations within the soil and the facing blocks. The material properties, instrumentations, and construction procedures are described. The test results indicated that the walls deformed very little with negligible horizontal acceleration amplification when subjected to the first shaking load. Deformation and horizontal acceleration amplification were reasonably small under the second shaking load. Part of the lateral deflection, earth pressure and tensile force in the reinforcement were recovered when shaking ceased. Amplification ratio of 1.35 indicated that the particular wall system performed better than conventional walls that had been tested for earthquake loading.