Experimental insights into the stiffness degradation of subgrade soils prone to mud pumping

Recent laboratory investigations conducted on soils prone to mud pumping have shown that the subgrade soil experiences softening associated with an internal redistribution of moisture when cyclic stress ratio (CSR) exceeds a certain critical level. This article aims evaluate stiffness degradation these problematic subjected wide range loading conditions. The test results revealed instability specimens is caused by early behaviour, and this accompanied sharp reduction in specimen stiffness. As high as 70–80% initial small-strain was observed even for densely compacted (ρd = 1790 kg/m3). In regard, new method predicting threshold number cycles, Nthr residual axial strains required onset proposed. useful practical guide, quasi-linear relationship between strain also determined.