Hydro-Mechanical Properties of an Unsaturated Frictional Material

5.4. EXPERIMENTAL PROGRAM 109
Table 5.4: General overview of flow experiments for investigation of hydraulic properties of
unsaturated Hostun sand
Cell e0 ψ0 S0 Test method σ Loading
MP P A 0.89/0.66 0 1 Steady state - Drainage, Imbibition
MP P A 0.89 0 1 Steady state 10.0/20.0 Drainage, Imbibition
SCI 0.89/0.66 0 1 Steady, transient state - Drainage, Imbibition
SCII 0.89/0.66 0 1 Transient state - Drainage
Table 5.5: Performed measurements during flow experiments
Cell Test method TDR Tensiometer Cumulative water
MP P A Steady state No No Yes
SCI Steady state Yes Yes Yes
SCI Transient state Yes Yes Yes
SCII Transient state Yes Yes Yes
overview of the conditions of the mechanical experiments. All the tests were performed in a
climate-controlled room (21 ◦ C ± 1 ◦ C).
5.4.1 Tests Performed using Modified Pressure Plate Apparatus
Water outflow and inflow experiments performed in the modified pressure plate apparatus are
element tests conducted on small and thus homogenous, reproducible sand specimens. The
experiments performed are steady state type tests.
All tests were started at water saturated conditions. The specimens were subjected to a
protocol of several predetermined suction steps using either a suction mode test or a pressure
mode test (i.e. axis-translation technique). The final gravimetric water content was calculated
by oven-drying (ASTM D2216) the specimen at the end of the test. Volumetric water contents,
degree of saturations and gravimetric water contents corresponding to each suction step were
back-calculated from these final values using incremental amounts of water flow from each step
Table 5.6: General overview of experiments for investigation of mechanical properties of
unsaturated Hostun sand
Cell e0 ψ0 S0 Loading Unloading Collapse
Oedometer 0.89/0.66 1.5/3.0/20.0/50.0 × ×
Oedometer 0.89 5.0 × × ×
Oedometer 0.89 1.0 × × ×