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can be left closed or nearly closed.) This is best done by means of a long push rod
(not supplied by Geokon) made from any easily available water pipe with threaded
connectors. The push rod assembly when joined should be sufficient length to reach
the bottom of the access tube. To open the telescopic couplings push down on the
push rod assembly and pull up on the access tubes.
4) Use the reed switch probe to verify the position of the anchors before they have been
tripped. (See Section 3 for information on taking readings.) If the anchors have
slipped it is still possible to remove the access tube and reposition them.
5) If the hole is to be grouted, it should be done at this time. Bentonite grout of the type
that will remain soft and not impede the settlement of the ground (i.e., grout that will
allow the anchor to follow the movement of the ground) should be used. (A typical
grout is 43 kgm cement, 2 kgm bentonite and 40 kgm water, or enough water to make
the mix thin enough to pump.)
6) If the hole is cased the casing can now be removed. Make sure that the access tubing
does not pull upwards during this process.
7) The magnetic spider anchors can now be released beginning at the top anchor. Select
pull-cable #1 and give it a quick hard pull.
8) Remove the pull-cable and anchor pull-pin completely from the borehole before
tripping anchor #2. Repeat this process for all the anchors.
9) Install the plastic tape guide by sliding the access tube into the slots in the guide (see
Figure 3).
2.3 Installation in Fills
Plate shaped magnetic anchors are used in fills. As the fill is placed the access tube is extended
upwards by screwing on more sections along with telescoping couplings (make sure these are
fully extended when installed). The plate anchors are laid on top of the fill surface as soon as it
reaches the desired anchor elevation. They are then buried as more fill is placed.
Each new section of access tube that is added will alter the reed switch probe readings; however,
the data reduction will still follow the method outlined in Section 4.
Figure 3 - Tape Guide Mounted to Access Tube
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