Hydro-Mechanical Properties of an Unsaturated Frictional Material

Chapter 6
Experimental Results
6.1 General
The following chapter gives an extensive overview of the experimental data derived from the
laboratory program.
Results of the steady state experiments performed in the modified pressure plate appa-
ratus are cumulative water outflow and cumulative water inflow versus time measurements.
These cumulative water flow measurements and the applied suction values lead to soil-water
characteristic curves of the investigated sand, which are also given in the section below. Ex-
perimental results performed in the column testing device I under transient state as well as
steady state flow condition and column testing device II under transient state flow condition
are pore-water pressure measurements and volumetric water content measurements observed
in several depth along the columns during draining and wetting the sand specimens. Further
these measurements are directly linked to the soil-water characteristic curve. Typical results
of the column testing device I experiments performed under transient state condition are also
pore-water pressure as well as volumetric water content profiles.
Experimental results from the one dimensional compression and rebound as well as collapse
tests are given that include strain versus vertical net stress as well as void ratio versus vertical
net stress data.
6.2 Soil-Water Characteristic Curve
For determination of the soil-water characteristic curve of Hostun sand, that includes the
initial drainage curve, the main drainage and imbibition curve as well as scanning drainage and
imbibition curve the following measurements from steady state or transient state experiments
were used:
- Cumulative water outflow and inflow measurements
- Pore-water pressure measurements
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