Rainfall infiltration performance and its relation to mesoscopic structural properties of a gravelly soil slope

- The infiltration performances of gravelly soils under different rainfall conditions were investigated by seepage tests.
- The significance of mesoscopic properties identified by CT scans on the permeability of gravelly soils was analyzed.
- Three permeability formulas expressed by gravel content, initial dry density and two mesoscopic properties were proposed.

Soil infiltration performances under rainfall affect shear strengths and play a crucial role in landslide problems. In this paper, the infiltration performances of gravelly soils under different rainfall conditions were investigated by 1D and 2D seepage tests. Computed tomography (CT) scans were adopted to identify the mesoscopic structural properties of gravelly soils. The significances of mesoscopic properties on the saturated coefficient of permeability (ks) were subsequently analyzed. The results showed a temporal and spatial variation of infiltration performances of a gravelly soil slope. The infiltration performances measured by 1D infiltration tests were different from those obtained from 2D tests. An exponential relationship between 1D and 2D infiltration rates was observed. The results further highlighted that void area ratio, uniformity coefficient, and gravel content were three most significant factors to ks. Three permeability formulas that respectively expressed by gravel content, initial dry density and two mesoscopic properties were proposed in this paper.