Experimental and numerical studies on the instability of simple homogeneous sandy slopes under different infiltration scenarios
In practice,many slope projects usually present complex infiltration boundaries due to functional requirements.In this paper,a series of physical experiments about rainfall slopes with different infiltration scenarios(rainfall covering slope crest only,slope surface only,and both slope crest and surface)were carried out.DIC image technology was used to capture the initial micro deformations and macroscopic overall asymptotic displacements during the slope failure.The contour maps of shear zones and contact force-chains were extracted,and the failure mechanism of high permeable soil slopes under different infiltration scenarios was revealed by the CFD-DEM numerical simulation.The results show that the rainfall covered slope crest only is easy to cause the failure of the slope toe first,then spread upward along the slope surface,and finally lead to the overall slip failure with the failure pattern of wide at the top and narrow at the toe.It had longer stability period,while its failure had characteristic of suddenness.When the rainfall covered slope surface only,plastic deformation was prone to occur first near the slope crown and slope toe.As two deformation areas continuously expanded and connected,it triggered the retrogressive failure with longer period.Its failure pattern presented narrow at the top,narrow at the bottom,and wide in the middle.When the slope covered by the full-area rainfall,overall failure was prone to triggered directly with characteristics of suddenness and linearity.Its failure pattern presented wide on the top,wide on the bottom,and wide in the middle.The scenario of rainfall covered slope crest only had the largest failure distance and failure depth,followed by the rainfall covered both slope crest and surface,while the scenario of rainfall covered slope surface only had the smallest failure distance and failure depth.The scenario of rainfall covered slope crest only was more dangerous than scenario of rainfall covered slope surface only due to the shorter failure period and sudden failure.In addition,the phenomenon of force-chain arch is prone to form at the back edge of the slip surface after the slope failure,indicating that the slope has the ability of self-stability.
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