Investigation on the seismic performance of steel-strip reinforced-soil retaining walls using shaking table test

The widespread use of reinforced-soil walls, especially in seismic regions has led to extensive studies on seismic behavior of this structures. In this paper, to assess the behavior and performance of steel-strip reinforced-soil retaining walls during seismic loading, a series of 1-g shaking table tests were conducted on 0.9 m high reinforced-soil wall models with different strip lengths. The physical models were subjected to variable-amplitude harmonic excitation at different peak accelerations and durations. It was found that the deformation mode of walls highly depends on the length of strips. The observed predominant mode of deformation was combination of bulging of the facing and rotation about the wall base without base sliding. The pattern of the observed failure mechanisms included a moving block which is delineated by a combination of a slant and reverse curve with certain intersection point. Irrespective of different steel strip lengths, the threshold acceleration corresponding to the onset of plastic displacements was similar and equal to 0.5 g for all models and the threshold acceleration corresponding to the onset of the development of active wedge failure was dependent on strip length so that this critical acceleration increased with increasing the strip length. Also, a consistent range of ∆x/H' between 0.2% and 0.8% (or ∆x/H'=0.2-0.8%) representing a transitional state of the walls from quasi-elastic to plastic state and a consistent range of ∆x/H' between 4.5% and 4.9% (or ∆x/H'=4.5-4.9%) representing a transitional state of the walls from plastic to failure state were observed. On the other hand, according to the sudden increase in wall displacements caused by decreasing the strip length from 0.7H' to 0.5H', the L/H' ratio of 0.7 was presented as the critical ratio in seismic conditions.