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Use the lugs on the cell as a template to locate the position for drilling holes for
the installation of expanding anchors or install the anchors nearby and use wire
to hold the cells in place. Alternately, the cell may be nailed in place using the
lugs as a guide.
Mix up some quick-setting cement mortar or epoxy cement. Trowel this onto the
surface then push the cell into the cement so that the excess cement extrudes
out of the edges of the cell. Hold the cell in place while the cement sets up then
complete the installation by adding the lag bolts (using the expansion anchors)
and tightening or nailing the cell in place. Protect the cell, transducer housing,
and cable from direct contact with large chunks of rock by covering them with a
fine-grained fill material from which all pieces larger than about 10 mm (0.5")
have been removed. This material is kept near the cell and cable as the fill is
placed. Additional cable protection can be achieved by using metal conduit
strapped to the surface of the structure.
2.2.3 INSTALLATION OF MODEL 4815 HYDRAULIC LOAD CELL
A particular installation, shown in Section 13, used the Model 4815 Hydraulic
Load Cell to measure the concentrated load on a tunnel lining from an existing
wooden pile (supporting a building above) that had been cut short by the tunnel
excavation in frozen ground. The load cell was designed to measure any
increase of load on the tunnel lining that might occur when, at the end of tunnel
construction, the ground was allowed to thaw out. The load cell was positioned
below the bottom of the pile and temporarily held in place with lugs and a
mortar pad until the shotcrete tunnel lining was sprayed.
13:
FIGURE 13: Model 4815 Hydraulic Load Cell Measuring Tunnel Lining Loads
2.2.4 INSTALLATION OF MODEL 4820 JACKOUT PRESSURE CELL IN
SLURRY TRENCHES
The Jackout Pressure Cell (JOPC) first needs to be assembled into the Jackout
frame (
part #4820-5 or 4820-6). The assembly is shown in Figure 14.
GEOKON
The support plate has a circular hole cut in it and bolt holes to fit the jackout
pressure cell and is connected to one end of a double-acting hydraulic jack by
means of steel struts. The support plate and reaction plate are cambered top
and bottom to prevent them from snagging on the sides of the slurry trench. The
reaction plate is attached to the other side of the double-acting hydraulic jack.
The jack is attached firmly to the rebar cable and arranged so that the plates are
10 | INSTALLATION | GEOKON
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