EARTH PRESSURES ON RIGID RETAINING WALLS IN SANDY SOIL WITH DIFFERENT ACTIVE MOVEMENT MODES UNDER ARBITRARRY DEFORMATION

Previous experimental and monitored results on earth pressures had shown that the resultant and distribution of active earth pressures on rigid retaining walls varied with modes and magnitudes of wall movement. The distribution of earth pressures sometimes differed obviously from a linear distribution according to classical earth pressure theories. A middle-state coefficient was adopted to define the non-limit state, and the formulae of the coefficients of the resultant earth pressures on rigid retaining walls in sandy backfills at a non-limit state with different deformations were proposed. The soil behind the wall was simplified as the combination of nonlinear springs and a rigid plasticity object which applied on the wall, and the unit active pressure and the heights of points of application of pressures were obtained. The comparisons among the proposed formulae, previous methods and the experimental observations showed that the proposed equations could predict the earth pressures with the three typical modes of wall movement more satisfactorily. It was also shown that the resultant earth pressures decreased gradually with the increase of translation of the wall and trended toward a certain value quickly and the distribution of the pressures kept linear all the while. However, the resultants of pressures could only be close to but not reached an active limit state and the distributions were nonlinear with a rotation mode. The distribution curves of the earth pressures were concave upward and the heights of the points of application decreased when a wall rotated about the base, while the curves were convex upward and the heights increased when the wall rotated about the top due to the soil arching.