Hydro-Mechanical Properties of an Unsaturated Frictional Material
Hydro-Mechanical Properties of an Unsaturated Frictional Material
Hydro-Mechanical Properties of an Unsaturated Frictional Material
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Chapter 7<br />
Analysis <strong>an</strong>d Interpretation <strong>of</strong> the<br />
Experimental Results<br />
7.1 General<br />
Based on the experimental results the hydro-mech<strong>an</strong>cial behavior <strong>of</strong> unsaturated Hostun s<strong>an</strong>d<br />
is <strong>an</strong>alyzed <strong>an</strong>d interpreted. Both the hydraulic functions, soil-water characteristic curve as<br />
well as unsaturated hydraulic conductivity <strong>an</strong>d the influence <strong>of</strong> suction on the volumetric<br />
mech<strong>an</strong>ical behavior is <strong>an</strong>alyzed <strong>an</strong>d interpreted.<br />
In the present study experimental soil-water characteristic curve results are best fitted<br />
using empirical <strong>an</strong>d physical models proposed in literature. For prediction <strong>of</strong> the model pa-<br />
rameters suction-water content results are best fitted using residual <strong>an</strong>alysis. Due to hystere-<br />
sis behavior during drainage <strong>an</strong>d imbibition, that also results in fitting sc<strong>an</strong>ning curves (e.g.<br />
sc<strong>an</strong>ning imbibition curves measured in s<strong>an</strong>d column testing device I experiments), it is a<br />
laborious procedure, when using models that do not consider hysteresis. Therefore a method<br />
is introduced <strong>an</strong>d implemented in Chapter 8 for <strong>an</strong> appropriate model that considers sc<strong>an</strong>ning<br />
imbibition curves.<br />
Attention is also paid to the volumetric mech<strong>an</strong>ical behavior that includes the influence<br />
<strong>of</strong> suction on the compression index <strong>an</strong>d the stiffness modulus respectively <strong>an</strong>d the collapse<br />
potential. An equation that considers suction, when calculation the stiffness modulus is<br />
proposed. Further it is investigated if the applied suction influences the soils history in case<br />
<strong>of</strong> preconsolidation pressure.<br />
7.2 Soil-Water Characteristic Curve<br />
The empirical equations (Eq. 2.9 to 2.11) introduced in Chapter 2 were used for determination<br />
<strong>of</strong> the soil-water characteristic curve. Following the statistical assessment described below in<br />
detail, best fit between experimental results (observed values) <strong>an</strong>d the soil-water characteristic<br />
curve model (predicted values) was estimated.<br />
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