Installation; List Of Suggested Tools; Installation In Boreholes; Preparing The Access Tube Anchor String - Geokon 1900 Instruction Manual

Magnetic extensometer
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2. INSTALLATION

2.1 List of Suggested Tools

• Black electrical tape (securing pull pins, packing pull cables, to protect loops)
• Masking tape (to hold pull cables during installation)
• Small cutting tool (to cut cable ties)
• Measuring tape (to place the anchors on the access tube at correct depth)
• Pen of Marker (to identify anchor location on access tube)
• PVC glue (for bottom cap)
• Steel saw (to cut access tubing)
• Long pushrod, typically threaded water pipe (extensible to reach the bottom of the hole)
• Color tapes to identify pull cables (or ID numbers)
• Small and medium plastic cable ties or cable clamps/grips (for making loops with the cable)
• Medium cutting tool (to cut pull cable)
• Small cutting tool (to cut cable ties)
• Measuring tape (to place the anchors on the access tube at correct depth)
• 300 ft. tape (to measure pull cable length)
• Working gloves (to hold anchor legs closed when working with the chain and the access
tube)cable
• Grease for telescopic sections (and possibly for anchors)
• Clear water (to clean threads)
• Pipe wrench (for threaded water pipe)

2.2 Installation in Boreholes

Boreholes may be open, cased, grouted, or not grouted. In cased boreholes, it will be necessary
to pull the casings after the string of access tubes and anchors have been installed inside it. In
holes that are to be grouted using a soft bentonite grout there are two options: a) to pre-grout the
borehole or b) to grout the borehole through a tremie pipe after the extensometer string has been
lowered into position.

2.2.1 Preparing the Access Tube Anchor String

It is advisable to prepare the entire access tube string on a stretch of clean, level ground
prior to installing it. In this way, there will be a minimum of delay during the actual
installation since everything will be ready. Do not screw the sections together; just
arrange them in their correct order with the anchors attached.
1) Begin by cementing the end cap onto the bottom section of the access tubing using
PVC cement (not supplied by Geokon).
2) Using three set screws, tighten the datum magnet onto the bottom section of the
access tube about one meter above the bottom end cap. (Do not put the datum magnet
too close to the bottom in case the access tube silts up.)
3

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