Studying the lateral displacement of retaining wall supporting sandy soil under dynamic loads

When Rankine or Coulomb theories are used to design a retaining wall, it is accepted that the retaining wall will experience a lateral displacement. By allowing the wall to move laterally, the earth pressure decreases on the active side of the wall and wall and earth pressure increases on the passive side, and therefore, more economical walls can be obtained when the lateral displacement is allowed. This lateral displacement is usually not calculated when designing a retaining wall. An experimental investigation is carried out to study the lateral displacement of a retaining wall subjected to dynamic loads with different load amplitude vibration, absolute frequencies, backfill sand relative densities, and different distances between the retaining wall and the loading source. The objectives of this study are to trace the lateral displacement of retaining wall under dynamic loads other than earthquakes such as the traffic load caused by trucks or railroads by direct measurement of displacements. The model footing used in this study is square. On a cohesionless soil, the tests were carried out using a dynamic load. The studied variables were as follows: three load amplitudes (0.25, 0.5, and 1 ton), three vibration frequencies (0.5, 1, and 2 Hz), two relative densities of sandy soil (30% loose sand and 70% dense sand), and three different distances between the foundation and the retaining wall. Observations show that the lateral displacement increased by increasing the load amplitude and decreased by increasing the distance between the foundation and the retaining wall. There is insignificant consequence of frequency on the cumulative lateral displacement. The lateral displacement decreased by increasing the density of sandy soil.