Principle and application
Piezometers are instruments installed in the ground to measure pore pressure, the pressure of water in the soil pores, over time. Because a rise in pore pressure is one of the main causes of failure in dams and slopes, continuous readings give the early warning that the safety of the works requires.
The test in stages
Borehole and installation
The piezometer is installed at the target elevation, with sealing between layers.
Sealing
Bentonite isolates the measured interval, ensuring readings from the correct layer.
Reading
Manual or automatic, producing the pore pressure time series.
Monitoring
Continuous follow-up with alert thresholds.
In terms of pore pressure
| Pore pressure | Pressure of water in the soil pores |
|---|---|
| Time series | Evolution over time |
| Piezometric level | Hydraulic head at the installed elevation |
| Alerts | Monitored safety thresholds |
Quality and field operation
Data quality
- Instruments calibrated and suited to the soil type.
- Controlled sealing to isolate the measured layer.
- Readings recorded and traceable.
- Installation by a crew trained in instrumentation.
Safety and operation
- Qualified for high-compliance areas: mining, industry and ports.
- Organised, signed work front with an HSE procedure in place.
- Own crews and fleet, including night shifts.
The deliverable
| As-built | Installation profile with elevations and seals |
|---|---|
| Readings | Pore pressure time series |
| Layout | Position of the instruments |
| Typical lead time | According to the number of instruments |
Sectors and project types
Frequently asked questions about piezometers
What are piezometers used for?
Piezometers are instruments installed in the ground to measure pore pressure, the pressure of water in the soil pores, over time. Because a rise in pore pressure is one of the main causes of failure in dams and slopes, continuous readings give the early warning that the safety of the works requires.
Why measure pore pressure?
Because rising pore pressure reduces soil strength and is one of the main causes of failure in dams and slopes. Monitoring it gives the early signal to act.
Which piezometer to use?
It depends on the soil and the response required, from open standpipe (Casagrande) to vibrating wire. The choice is part of the instrumentation design.
Piezometers in waste rock piles
Technical bulletin on pore pressure instrumentation in mining structures.
Piezometers for your project
Tell us about your project and we will prepare the investigation plan and the quote.