Model Tests of Seismic Stability of Several Types of Soil Retaining Walls

This chapter describes how, in order to establish a practical and relevant design procedure to evaluate the seismic stability of different types of soil retaining walls against high seismic loads, a series of irregular shaking tests was conducted on six different retaining wall models. In some tests, after the first failure plane was formed in the backfill, the second failure plane was formed at higher seismic loads. This can be explained by considering the effects of strain localization in the backfill soil and associated post-peak reduction in the shear resistance from peak to residual values along a previously formed failure plane. This behavior has not been observed in the tilting tests and the sinusoidal shaking tests that were performed on the same models in the previous chapter. In the present series of tests, reinforced soil retaining wall models with a full-height rigid facing exhibited ductile behavior compared to conventional-type retaining wall models such as gravity-type, leaning-type, and the cantilever-type ones. The tilting of the conventional type retaining wall models was associated with the concentration of subgrade reactions at the wall toe, which resulted in local soil failure due to a loss of bearing capacity. Under similar conditions, tensile force in the reinforcements of the reinforced soil retaining walls was mobilized effectively to resist against the tilting displacement. Comparisons are also made on the resultant force of normal earth pressures and the critical seismic coefficient at the ultimate overall wall failure condition.