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Tuesday, 22 May 2018
Extensometric measurements

Purpose: Extensometers are used to measure the relative displacements between two points; most commonly the change in length between the measuring head mounted at the surface and the root anchored in the borehole in the rock massif. The most common applications are the measurements of deformations around tunnel openings and monitoring of volume changes (settlement, expansion, ...) in structures foundations. You can use extensometers also in the case of hardly-accessible unstable rock slopes or waterworks objects. The reading of the deformation may be either manual or automated.

Description: The extensometer is composed of the head, rod and the root. The root is firmly attached to the rod, casing serves to enable free movement of the rod in the borehole. The rod extensometers can be mounted solely or several of them of different lengths in a single borehole. According to the terms you can use different types of roots (grouting, hydraulic, mechanical). The extensometric heads are of different constructions depending on the way of reading (mechanical measuring instruments, gauges, reading units, data-loggers, ...).

Extenzometre s diaľkovým odčítavaním


Maximum length of extensometer:

Maximal number of extensometers in one borehole:

Accuracy depending on the extensometer’s length:

Measurement range:

150 m

6 pcs

from 0,01 mm to 1 mm

from 25 mm to 50 mm, after re-adjustment to 300 mm

Installations of extensometers in tunnel Installations of extensometers in tunnel Portable readout devicePortable readout device Complete extensometer with hydraulic anchorComplete extensometer with hydraulic anchor