Earth Pressure on Retaining Walls Near Rock Faces

The present study examines the lateral earth pressure transferred to a rigid retaining wall by granular fill confined between the wall and an adjacent rock face. The centrifuge modeling technique is used to test small models in which rotation of the wall about its base can be controlled, thus allowing observation of changes in pressure from the at‐rest to the active condition. Janssen's silo pressure equation may be reasonably used for estimation of the atrest pressure, using an earth pressure coefficient, K=1-sinΦ. Significant variations from the estimated pressure may occur next to the wall as a result of small variations in placement conditions. A conservative approach may be to use a decreased Φ value in calculating K. In the active condition, progressive failure in the soil results in a decreased Φ, which should be used when estimating wall pressure. These estimates may be obtained from stress characteristic solutions, or from the silo pressure equation in which a K value compatible with the values of Φ and δ (wall fraction angle) is used.