Typical applications for piezometers are:

• Monitoring pore water pressures to determine safe rates of fill or excavation;
• Monitoring pore water pressures to evaluate slope stability;
• Monitoring dewatering systems used for excavations;
• Monitoring ground improvement systems, such as vertical drains and sand drains;
• Monitoring pore pressures to check the performance of earthfill dams and embankments.

Types of Piezometers:

Vibrating Wire Piezometers

The vibrating wire piezometer is the most commonly deployed piezometer and is suitable for almost all applications. It consists of a vibrating wire pressure transducer and signal cable. It can be installed in a borehole, embedded in fill, or suspended in a standpipe. Readings are obtained with a portable readout or a data logger.

Advantages:
Easy to read, very accurate; good response time in all soils; easy to automate; reliable remote readings.

Limitations:
Must be protected from electrical transients.

Pneumatic Piezometers

The pneumatic piezometer operates by gas pressure. It consists of a pneumatic pressure transducer and pneumatic tubing. It can be installed in a borehole, embedded in fill, or suspended in a standpipe. Readings are obtained with a pneumatic indicator.

Advantages:
Reliable, remote reading possible, not electrical, indicator can be calibrated at any time.

Limitations:
Accuracy depends on skill of operator; difficult and expensive to automate, so reading requires man on site; reading time increases with length of tubing; pneumatic tubing can be blocked by condensation if not frequently charged with dry nitrogen gas.

Standpipe Piezometers

The standpipe piezometer is the most basic of piezometer types. It consists of a filter tip joined to a riser pipe. Water flow from the surrounding soil into the standpipe. Readings are obtained with a water level indicator.

Advantages:
Yesple, reliable, not electrical, no calibrated components.

Limitations:
Accuracy depends on skill of operator; reading requires a man on site; remote reading not possible; slower to show changes in pore-water pressure.

Comparison of Piezometers
	Standpipe	Pneumatic	Vibrating Wire
Response	Slow	Fast	Fast
Precision	High	Medium	High
Automation	Impossible	Difficult	Yesple
Connect to Data Logger	No	No	Yes
Potential for Lightning Damage	No	No	Yes