Encardio-rite Borehole Vibrating Wire Extensometer is a specially designed instrument that assists civil engineers and geologists in the measurement of deformation of rock mass and adjacent or surrounding soil. Coupled with anchor bolt load cells and tape extensometer, it makes an essential geotechnical instrument for investigating and monitoring of foundations, slopes & embankments and for studying the behaviour of rock around underground cavities, tunnels and mines.
Vibrating Wire Extensometer- Applications
To predict the behaviour of a roof or wall of mine, underground cavity or tunnel during excavation.
To forecast a potential roof or wall fall before their occurrence as they are preceded by measurable sags as the strata open up and the movement usually occurs at an increasing rate as fall conditions are approached.
Extensometers are used to estimate and monitor the movements in slopes and foundation which occur due to excavation of underground cavities or due to construction of heavy structures like concrete, rockfill, masonry or earth dams over the foundation.
Suitable for upward or downward sloping hole using fibreglass or stainless steel AISI-410 connecting rods.
Encardio-rite Model EDS-70V Features:
Three extensometers can be mounted in a borehole of 76 mm. Diameter at the mouth of the borehole is increased to 90 mm (300 mm depth for 50 mm displacement sensor or 430 mm depth for 100 mm displacement sensor).
Provision for mounting up to six extensometers in a borehole of 102 mm. Diameter at the mouth of the borehole is increased to 125 mm (300 mm depth for 50 mm displacement sensor and 430 mm depth for 100 mm displacement sensor).
Borehole Vibrating Wire Extensometer is used to measure the displacement that takes place in a bored hole or several bored holes in a rock mass, with respect to time. It is equipped with one or more anchors and a reference plate.
Anchor or Anchors are usually placed in the same borehole or drilled adjacent to the first borehole in case of placing them in different boreholes.
The Borehole Extensometer assists in measuring the distance between various anchors with respect to the reference plat and thus helps monitor with time their relative displacement in respect to each other. It is usually assumed that deepest anchor is in the stable ground and so any change in anchor spacing is interpreted as sag of roof bed, movement of sidewall or slope, settlement of foundation etc.
Encardio-rite EDS-70V Vibrating Wire Extensometer can be mounted in a borehole and the displacement is monitored with the help of vibrating wire displacement sensors.
At places where access to the mouth of the borehole is easily available, mechanical displacement measurement is economical and reliable, with displacement reading taken by a micrometre depth gage which measures the depth of reference button at the near end of connecting rod from a reference plate.
Model EDS-70V borehole vibrating wire extensometer comprises of four major sub-assemblies ...[Continue Reading]
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