Hydro-Mechanical Properties of an Unsaturated Frictional Material

List of Figures
1.1 Global Humidity Index (from UNEP/GRID and UEA/CRU) . . . . . . . . . . 2
2.1 Fabric types of a soil: a) fabric consisting of elementary particle arrangements
of clay platelets and coarse grains including intra-matrix pores, b) fabric con-
sisting of elementary particle arrangements of clay platelets and coarse grains
joined together to aggregates including inter -and intra-aggregate pores, c)
fabric consisting of elementary particle arrangements including intra-element
pores between clay platelets . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9
2.2 Fabric of a granular material . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9
2.3 3 Phase system representing unsaturated soils . . . . . . . . . . . . . . . . . . 12
2.4 Rise of water in capillary tubes of different diameter (Lu & Likos 2004) . . . . 14
2.5 Equilibrium between two interconnected drops of water - the effect of drop’s
radius (Lu & Likos 2004) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14
2.6 The interaction between air and water (Lu & Likos 2004) . . . . . . . . . . . . 15
2.7 Soil-water characteristic curves for different types of soils . . . . . . . . . . . . 17
2.8 Typical soil-water characteristic curve parameters and zones . . . . . . . . . . . 19
2.9 Soil-water characteristic curve showing the initial drainage curve, main imbi-
bition curve, main drainage curve and scanning curves . . . . . . . . . . . . . . 20
2.10 Raindrop effect visualized by a drop running down a homogeneous surface and
in tubes during drainage and imbibition process (Bear 1972) . . . . . . . . . . . 21
2.11 Capillary rise in tubes different in diameter and drainage as well as imbibition
process in tubes with varying diameters (Haines 1930, Miller & Miller 1988) . . 22
2.12 Influence of the pore geometry on the inclusion of a fluid caused by snap-off
effect (Chatzis and Dullien 1983) . . . . . . . . . . . . . . . . . . . . . . . . . . 22
2.13 Influence of the pore geometry on the fluid placement caused by by-passing
effect (Chatzis and Dullien 1983) . . . . . . . . . . . . . . . . . . . . . . . . . . 23
2.14 Exemplary hydraulic functions (soil-water characteristic curve - top, hydraulic
conductivity function - middle, relative hydraulic conductivity function - bot-
tom) for sand, silt and clay . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24
2.15 Experimental results for Hostun sand from drainage: soil-water characteristic
curve and fitted results using empirical models . . . . . . . . . . . . . . . . . . 42
VII