Products & Services

Extensometers

Single Point Mechanical Rod Extensometers

Model A-1

The Model A-1 Single Position Rod Extensometer is a very simple, rugged and reliable instrument, easily installed and completely recessed within the borehole for optimum protection. The Model A-1 is a natural first choice for monitoring the safety in and around tunnels and mine openings.

Specifications
Standard Range up to 100 mm
Least Reading 0.025 mm
Borehole Diameter 35, 44, 51, 64 mm
Maximum Length 10 m


Multiple Point Rod Extensometers, Groutable Anchor

Model A-3

The Model A-3 Multiple Point Rod Extensometer is the preferred design for installation in downward directed boreholes which are easily filled with cement grout. Up to eight anchors can be installed, at various depths, in a 76 mm diameter borehole providing the capability to locate multiple failure plains and zones of movement.

Specifications
Standard Range up to 300 mm nominal
Least Reading 0.025 mm
Borehole Diameter 76 mm or over
Maximum Length 100 m


Multiple Point Rod Extensometers, Snap-Ring Anchor

Model A-4

The Model A-4 Multiple Point Rod Extensometer with Snap-Ring Anchors is quickly and easily installed in boreholes in hard or competent rock. Anchors are pushed to the required depth on the end of setting rods and then a cord is pulled to remove the locking pin which allows two retaining rings on each anchor to snap outward and grip the borehole. Up to eight anchors can be installed, at various depths, in a 76 mm diameter borehole. Particularly useful in upward directed boreholes.

Specifications
Standard Range up to 300 mm nominal
Least Reading 0.025 mm
Borehole Diameter¹ 38 mm to 76 mm
Maximum Length 50 m

¹Any borehole diameter up to 76 mm may be specified. Note that the size of the borehole required increases with the addition of more measuring points.



Multiple Point Rod Extensometers, Hydraulic Anchor

Model A-5

The Model A-5 Multiple Point Rod Extensometer with Hydraulic Anchors is recommended for use in soft ground and soils or in rock where the borehole may deteriorate. This anchor is very versatile and can be used in boreholes of varying diameter and roughness oriented in any direction.

Specifications
Standard Range up to 300 mm nominal
Least Reading 0.025 mm
Borehole Diameter¹ 38 to 102 mm
Maximum Length 100 m

¹Note that the size of the hole required increases with the addition of more measuring points.

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