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A vibrating wire piezometer is a fluid pressure measurement instrument using a proven technique of converting fluid pressure on a sensitive diaphragm into a frequency signal.
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A vibrating wire piezometer is a fluid pressure measurement instrument using a proven technique
of converting fluid pressure on a sensitive diaphragm into a frequency signal. Frequency signals are
ideal in Civil Engineering applications where work is conducted in demanding environments because
they can travel long distances without degrading. Moreover, they can resist external electrical noise
and tolerate wet wiring conditions. A piezometer is typically used in applications like finding the
fluid pressure in pump and hydro-fracture tests and measuring the pore pressure in rocks and
Vibrating Wire Piezometers operate as follow:
When the tension wire is plucked by an electronic pulse to the measurement coil which
surrounds the wire it vibrates at a resonant frequency, thus activating the gauge.
A magnetic coil surrounds the wire, when the wire is plucked and vibrates an electric signal
is created which can be used to find the vibration’s resultant resonant frequency.
On a VW piezometer, the wire is tensioned between an anchor point and a diaphragm. The
changes in the distance between the diaphragm and the anchor are related to the pressure
differentials. They can be converted into a kPa reading.
Temperature information can be utilised from an internal temperature sensor if regular
logging is required. This way, swift changes in temperature can be determined as pressure
readings have the potential to be exaggerated.
Measuring the pore pressure of groundwater can help you understand the behaviour of the ground.
This data can be most especially crucial before, during, and after a construction project. A
conventional piezometer is an open standpipe made of plastic pipe that is 19mm in diameter, with a
porous area at the bottom. It is installed in a borehole with the porous section situated at the
depth where you need to measure pore water pressure. Sand is used to fill an annulus between the
borehole and the filter, then sealed with bentonite before the remaining area of the borehole is
filled with grout, which is typically made of cement and bentonite. Results are normally collected by
measuring the height of water, but VW piezometers can directly record pressure allowing for
automatic data collection
Certain features make high-end piezometers reliable when measuring pressure of groundwater in
the most demanding conditions. A vibrating wire piezometer for instance, has a rugged
construction so it can withstand the harshest environments and guarantee long-term, reliable
performance. The device is insensitive to the length of a cable, so it does not matter if you use a
long cable. Be sure to purchase a piezometer from a reputable provider, especially if you are
buying a non-drive-in model. That way, you can have it customised as per your unique