Grouting Down-Holes A single grout tube is usually adequate for vertical and inclined
down-holes. Tape the end of the tube to the protective sleeve a few
feet from the bottom anchor, so that the tube is drawn into the bore-
hole as the extensometer is installed. Sometimes a second, shorter
grout tube is taped to a protective sleeve about half-way down the
length of the extensometer. This tube can be used if difficulties arise
with the longer tube. When grouting begins, pull the tube free from
the protective pipe. Draw it upwards as the level of grout rises in the
borehole.
Grouting Up-Holes
1
Tape a tube to the protective sleeve so that it projects beyond the
deepest anchor. This will act as a vent tube. Tape a second tube so
that it reaches the deepest anchor. Tape a third tube to the protec-
tive sleeve so that it ends 2 to 3 m up from the borehole collar.
2
Insert the extensometer and tubes into the borehole. Seal borehole
collar with rags soaked in quick-set cement, and pump grout into
borehole through the shorter grout tube to form a plug.
Allow time for the grout to set.
3
Pump grout into the borehole using the longer grout tube.
Grouting is complete when grout exits the vent tube. Fold tubes
and tie off with wire.
Other Considerations The most common problems with extensometers are mechanical
damage to the instrument head, dial indicator, signal cable, or signal
connectors, and moisture or dirt in the signal cable connectors or
dial indicator. In wet installations subjected to freezing tempera-
tures, ice accumulations in or near the instrument head may interfere
with instrument operation. To protect the reference head, install a
cover or recess the head at installation.
Borehole Extensometers
Rembco Geotechnical Contractors specializes in
slope stabilization,
soil nail wall,
foundation repair
and support,
grouting,
shoring,
micropile
construction,
rock drilling, and we remediate
sinkholes. We use a
problem-solving approach in the geotechnical portions of buildings, bridges, water plants, sewage plants, tunnels,
installing caisson bottom, and roads. We are experienced in these applications:
micro piles,
sinkhole repair,
permeation and
pressure
grouting,
soil nails,
cement grouting,
chemical grouting,
micropiles,
compaction grouting, and
rock anchors.
Rembco techniques apply when adding new structures: especially
rock anchor,
microfine cement,
soil nailing, and
micropile
installations for foundation support. Our specialties are
soil nails,
rock anchor,
chemical and
compaction grouting,
mini piles,
sinkhole repair,
micropiles, and
soil nailing.
