Piezometers (electrical resistance or vibrating wire) are designed for accurate and long term measurement of pore water pressures in fully or partially saturated soil and rock.
This is particularly useful in estimating slope stability, safe placement rate of fill or excavation, design and build for lateral or uplift pressures or buoyancy, monitoring the performance of earth-fill dams and embankments, seepage and verify models of flow, monitor surface water run-off, water levels at contaminated sites etc.
Both Vibrating Wire or Electrical piezometers are robust, have excellent long term stability and can be used with long cable lengths without any signal degradation.
The piezometer comprises a porous filter tip element (high or low air entry) integral with a diaphragm type pressure transducer. A cable connects the transducer to a read-out, terminal unit or data-logger and the data is then recorded and converted to engineering units.
Piezometers are installed in different ways depending on the application and soil condition. Typically, they are installed in fully grouted boreholes (or surrounded by a sand filter) at the desired depth (a bentonite plug may be formed above the sand filter, if present, and the remainder of the borehole is filled with a bentonite-cement grout).
|Fully Grouted Piezometers GIN||John Dunnicliff||2008||Download|