Hydro-Mechanical Properties of an Unsaturated Frictional Material

6.2. SOIL-WATER CHARACTERISTIC CURVE 121
Pore-water pressure (kPa)
Pore-water pressure (kPa)
6
4
2
0
-2
-4
-6
6
4
2
0
-2
-4
-6
Loose specimen
Initial void ratio = 0.89
Initial drainage 1st imbibition
2nd imbibition 2nd drainage
1st drainage
0 200 400 600 800 1000 1200 1400 1600 1800
Time (min)
Dense specimen
Initial void ratio = 0.66
Initial drainage
T 70 mm T 160 mm T 260 mm T 360 mm T 450 mm
2nd imbibition 2nd drainage
1st imbibition 1st drainage
0 200 400 600 800 1000
Time (min)
T 70 mm T 160 mm T 260 mm T 360 mm T 450 mm
TDR
Depth 70 mm
Depth 160 mm
Depth 260 mm
Depth 360 mm
Depth 450 mm
Hydrostatic
pressure
Matric
suction
Hydrostatic
pressure
Matric
suction
Figure 6.6: Suction measurements for drainage and imbibition processes from transient state
column test I (loose specimen-top, dense specimen-bottom)
program to an initially saturated specimen several flow rates were induced for several flow
processes:
1. Initial drainage process with an applied flow rate of approximately 30 ml/min.
2. First imbibition/ drainage process with an applied flow rate of approximately 30 ml/min.
3. Second imbibition/ drainage process with an applied flow rate of approximately
100 ml/min.
Tensiometer