عنوان مقاله [English]
The use of retaining walls is one of the most common approaches for construction of retaining soil structures around the world. These walls have remarkable flexibility against earthquake loads and are less sensitive to
settlement. In many retaining wall problems, it is necessary to determine the additional earth pressure produced by surcharge loads acting on the soil surface behind the wall. Considering the application of various surcharge loads on the backfill in such systems, the necessity has been felt, over recent decades, to find an appropriate method for calculating the effect of surcharge on active earth pressure in retaining walls.
In this study, based on analytical methods, previous formulations of horizontal slices methods are improved, and a new formulation has been proposed for estimating the effect of surcharge on the active earth pressure of retaining walls with a cohesive-frictional backfill. Using a comparison of the analytical results obtained from the proposed method with those of previous research, it was concluded that the analytical procedure proposed reliably calculates active earth pressure due to surcharge in cohesive-frictional soil.
The variations of angle of failure wedge versus intensity of surcharge indicate that an increase in the intensity of the surcharge causes an increase in the angle of the failure wedge, but, a change in the distance of the surcharge from the wall does not affect the angle of the failure wedge significantly. Also, the results show that by an increase in the distance of the surcharge from the wall, lateral pressure decreases, and that moving the surcharge out of the failure wedge has no effect on active earth pressure. Comparisons show that the
results from the suggested method are a lower bound for values obtained by recommended methods in ASHTOO (2007) and U.S Army Crops (2005) codes. The suggested method is also in good agreement with that of Motta (1994).