PARTIALLY-DRAINED CYCLIC BEHAVIOR AND ITS APPLICATION TO THE SETTLEMENT OF A LOW EMBANKMENT ROAD ON SILTY-CLAY

This study examines the phenomenon of settlement induced by traffic loading on low embankment roads built on soft cohesive soils deposited in a reclaimed lowland. A series of cyclic triaxial tests were conducted on undisturbed soft Ariake silty-clay under undrained and partially-drained conditions. A model based on the test results is proposed to simulate the partially drained behavior of silty-clay under a variety of lateral stresses. It is shown that the maximum excess pore pressure generation ratios and volumetric changes increase until the cyclic stress ratio reaches a value of 0.73, which is independent of the effects of lateral stresses under the same anisotropic consolidation ratio. Numerical analyses applying the proposed model were performed to compare the effects of soil thickness and cyclic loading time during one day and one cycle on partially drained cyclic behavior. It was found that a large ratio of cyclic to non-cyclic loading time during one cycle exerts a smaller influence on volumetric strain than the total time of cyclic loading during oneday. Observed settlement results of a low embankment road are analyzed to verify the applicability of the proposed model.