Environmental Engineering Reference
In-Depth Information
High
Pressure
300
300
280
280
+
−
260
260
240
240
220
220
200
200
High
180
180
160
160
Volume
tube
Low
140
140
Load plate
120
120
100
100
Load shaft
80
80
−
+
60
60
40
40
Low
Pressure
20
20
Compensator
Top
plate
Cell
Bottom
plate
300 mm
300 mm
Side view
Front view
Figure 5.88
Front and side views of the GCTS pressure plate cell and the control panel.
(Courtesy of GCTS, Tempe, AZ.)
5.9.4 Golder Basic Pressure Plate Cell (Fredlund,
and Stone, 2011)
A pressure plate device was designed by members of
the Golder Unsaturated Soils Group, Golder Associates,
Saskatoon, Canada. The primary design specifications are
as follows:
1. The pressure plate device should accommodate a single
soil specimen.
2. The pressure plate cell should have a minimum of
parts.
3. The device must have a high design factor of safety
against breakage under high air pressures.
4. The pressure plate design should accommodate vari-
ous ceramic disks with air-entry values up to 500 and
1500 kPa.
5. The device only needs to be designed to measure the
drying curve.
6. The effect of air diffusion should be minimized.
7. The device must be sufficiently light such that the
device and soil specimen can be weighed to
±
0.01 g
on a balance.
8. The air supply at the top of the device should have a
quick connector that maintains the internal air pressure
in the cell when disconnected.
Figure 5.91 shows the SWCC cell designed by the Golder
Unsaturated Soils Group. The device meets the desired
specifications for safety and simplicity. The pressure plate
cell has been manufactured by GCTS. Silt, sand, and clay
soils have been tested to verify the functionality of the
new cell.
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