In case of: tunnels and landslides; dams and mining excavations; underground openings, cut scope and trenches and foundations; OTR suggest the use of Multy rod extensometer OG700.

Following the demand it’ll be selected mono or multy base extensometer, cemented at different quotes previously setted inside a drilling. Between measuring surface and the base are placed stainless steel rod coated with anti-friction sheaths to increase their slipping.

Functionally to the relative movement of the rods, compared to the cemented bases, the measure should be defined using a digital dial gauge –manually- or using electric or wibrating wire displacement sensors –automatic.

How is it installed?

To instal the prodouct is necessary a 101mm hole diameter.

For every measure in stainless steeel or INVAR: screw the first measuring rod to the conical quill and then assembalate every rod till the project lenght, cutting with a hacksaw the redundancy and pasting it on the measure terminal. At this point laydown the anti-friction sheaths, with the same lenght of the every base, and cut it with the hacksaw. Inserting for every base the temples inside the sheaths till the lockout on the lower anchor forcing the lock and pasting it with scotch tape.

After that, take off the anti-friction sheaths and, taking care to leave the temples’ terminals uncovered about 50cm, fit the upper anchor on the measuring base taking care to take the sheaths inside the site till the end.

For glass fibre models: instrument is already assembled. There are M6 screws installed inside dinghies to keep the position of the rod during the installation.

For every model: insert the anchors on the head and tighten the fixing screws on the upper anchoring recess, then lay down the injection tube for all the long base length and cut it using hacksaw. Prepare a measuring piece about 1m long and assemble all the bases together with the injection tube taping them every 2m from inside the instrument, to facilitate insertion into the hole. Finish by anchoring the measuring heads to a wall with plugs and inject the cement mortar through the ignition tube.