Rod Material Tensioned-Rods: Fiberglass or aluminum rods offer similar
performance and ease of installation. Fiberglass is not subject to
corrosion.
Untensioned-Rods: Stainless steel or fiberglass rods are available.
Stainless steel rods are shipped in ten-foot lengths and are threaded
together during installation. Steel rods may offer better performance
under compression, but can be difficult to install in confined areas,
such as small diameter tunnels. Fiberglass rods are shipped in con-
tinuous lengths and require little clearance for installation.
Anchors Groutable Anchors: Easy to install, prevents migration of water
through borehole, suitable for long term monitoring. Requires grout-
ing equipment. Strength of grout must be similar to surrounding
ground. If grout is too stiff, anchor system may fail at grout/ground
interface. Also, grout should allow anchor to move with surrounding
ground. Sometimes styrofoam spacers are placed up and down-hole
of anchor to ensure free movement. Cannot be used if ground has
too many fissures or openings.
Hydraulic Anchors: Bladder type is useful for a wide range of rock
type and can also be used in concrete. When the bladder, a coiled
copper flat jack, is activated, it uncoils to press against borehole
wall. The prong type is useful in soils. When activated, prongs ex-
tended outward into the ground. The single-acting anchor has three
prongs; the double-acting anchor has six prongs and is better suited
to deep holes or critical applications. Both bladder and prong type
anchors can be grouted to block flow of water through borehole.
Hydraulic anchors are more expensive than groutable anchors. There
is no waiting time as for groutable anchors, so the extensometer can
be completed as soon as the anchor is activated. Hydraulic anchors
may be preferred in up-holes or when grouting is not feasible, such
as in highly fractured rock.
Mechanical Anchors: Used with short rods in good rock. Expan-
sion shells are activated mechanically by turning anchor bolt. Rods,
but not shells, can be retrieved for reuse. The mechanical anchor
system is not compatible with grouting, since rods are not encased in
protective sleeves.
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.
