Dynamic characteristics of preloaded and prestressed reinforced soil against level II shaking

The preloaded and prestressed (PLPS) reinforced soil method has been proposed to substantially increase the vertical stiffness of reinforced soil structures against level II shaking. To evaluate the seismic stability of PLPS reinforced soil structures, we performed a series of shaking table tests by using sinusoidal waves having an acceleration level of 700 gals to take similarity rule into account. A fine uniform sand or a well-graded gravel were used for the backfill. The gravel backfill exhibited a much higher dynamic stability under otherwise the same conditions. The maintenance of sufficiently high prestress was found to be the key for a high dynamic stability of the structure. The use of a ratchet mechanism was found to be very effective for this purpose.