Experimental Study on Permeability of Highway Embankments Subjected to Post-earthquake Rainfall

In this study, the effects of rainfall after an earthquake on the infiltration characteristics and stability of highway embankment structures were experimentally evaluated. A scale model of a highway embankment was used in the test, and nine cases were set with the initial density of the embankment (degree of compaction, D c) and the degree of damage caused by seismic motion (settlement of crest, d s) as variables. The rainfall intensity was set at 40 mm/h, and data such as water pressure head, h w during rainfall, and the time of occurrence of slope deformation, t f, were collected. As a result of the test, in the case of high-density embankment with D c = 90%, the number of cracks increased as d s increased due to vibration, and the time when h w began to rise was shortened. On the other hand, in the low-density embankment with D c = 85%, the density of the embankment increased after the earthquake, and the permeability coefficient decreased, which suppressed rainfall infiltration. The relationship between the number of cracks, n c, after the shaking and the rate of increase in hw per unit time, dhw/dt, showed that dh w/dt also increased as n c increased.