MODEL TESTS IN RETAINING WALL WITH LINE LOAD SURCHARGE

Abstract

Model tests were performed to study the rupture. surface and pressure distribution behind a retaining wall with concentra-ted line load surcharge parallel to the wall on the backfill. The study was made for Ranipur sand in dense state having a density of 1.6 gm/cc. All the three modes of wall displacements i.e. rotation about bottom, translation and rotation about top were considered. The study was made for both the active and passive states. Tests were conducted in a model tank of size 150 x 65 x 61 cm having a retaining wall of mild steel 49.50 cm high. The Wall could be given desired type of movement and displacement by means of a heavy driving screw. Deforming diaphragm type pressure cells were used to measure the earth pressure. The observed rupture surfaces were compared with some of the existing theories and it was concluded that in active state effect of point load was to reduce the size of rupture wedge when applied within the range of rupture wedge for zero surcharge. The rupture wedge increased when surcharge load was located outside the range of failure wedge for zero surcharge. Rupture wedge increased with the increase in surcharge intensity. For passive state the failure wedge was increasing or decreasing when the load was applied within or outside a distance equal to one and a half times the height of backfill. Rupture surface started just below the point load when the load was applied at distance equal to 1.50 times the height of backfill. The observed pressures at various surcharge intensities were in good agreement with the computed ones by Coulomb's theory