Lateral Earth Pressure Distribution and Shear Band Development within Back-to-Back Mechanically Stabilized Earth Walls Under Seismic Conditions

This study attempts to evaluate the effects of two important structural design parameters on the dynamic behavior of back-to-back mechanically stabilized earth walls (BBMSEWs). For this purpose, a series of shake table tests were carried out on seven BBMSEW models with different overlap lengths of reinforcements (L-R) and arrangements of connecting two opposing walls to each other. Based on the results of the particle image velocimetry (PIV), a combination of a concave surface and an inclined plane was observed as the failure surface in models and it was concluded that the complete connection of two opposing walls to each other could prevent the formation of a failure wedge in BBMSEWs. Findings indicated that although separating two opposing walls from each other and reducing the overlap L-R increase lateral deformations, these could be two effective solutions for reducing the lateral earth pressure in BBMSEWs. On the other hand, comparisons have showed that Seed-Whitman and Mononobe-Okabe methods are conservative for calculating dynamic lateral pressures (sigma(AE)) in BBMSEWs at HPGA < 0.6g (where HPGA is horizontal peak ground acceleration) and that this conservatism fades gradually by increasing HPGA, and finally at HPGA >= 0.9g, the obtained values of sigma(AE) becomes almost greater than those predicted by these methods.