Hydro-Mechanical Properties of an Unsaturated Frictional Material

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CHAPTER 7. ANALYSIS AND INTERPRETATION OF THE EXPERIMENTAL
RESULTS
Unsat. hydr. conductivity (10-4m/s)
Unsat. hydr. conductivity (10-4m/s)
Unsat. hydr. conductivity (10-4m/s)
3.0
2.5
2.0
1.5
1.0
0.5
0.0
Drainage loose specimen
Imbibition loose specimen
Drainage dense specimen
Imbibition dense specimen
Childs and Collis George (1950)
3.0 0.1
2.5
1
Matric suction (kPa)
10
Mualem (1976)
2.0
1.5
1.0
0.5
0.0
3.0 0.1 1 10
Fredlund et al. (1994)
Matric suction (kPa)
2.5
2.0
1.5
1.0
0.5
0.0
0.1 1 10
Matric suction (kPa)
Figure 7.12: Unsaturated hydraulic conductivity from modified pressure plate apparatus
(steady state test) determined by using statistical models (loose and dense specimen)
range of suctions up to the saturated zone. Drainage and imbibition hydraulic conductivity
curves show the phenomenon of hysteresis.
The unsaturated hydraulic conductivity function was first estimated indirectly by using
the best-fitted soil-water characteristic curve and the statistical models from sand column
tests I. Figure 7.13 shows the results from the loose specimen and the dense specimen. Sim-
ilar to the results achieved from modified pressure plate apparatus for both specimens the