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Fiberglass-Rod MPBX

The fiberglass-rod MPBX is a flush-mounted multi-point borehole extensometer designed to monitor settlements and deformations in busy locations that are difficult to access, such as city streets, highways, airport taxiways, and port facilities. Fiberglass-Rod MPBX and Digital MPBX

Wireless MPBX


An MPBX includes anchors, rods, a reference head, and sensors. Anchors are joined to rods and installed at specified depths in the borehole. Rods run upwards from the anchors to the reference head, which is installed at the surface. Sensors inside the reference head monitor the rods, which follow the upward or downward movement of the anchors.

The MPBX is terminated flush with the surface with a waterproof canister containing a wireless data logger and long-life battery pack. The logger transmits measurements to the internet via a cellular connection. GEO’s traffic-rated Lid-Link® antenna is used, if necessary, to ensure reliable transmissions.


The MPBX can be adapted to suit almost any site conditions. Some of the options are:

Monitored Points: The MPBX can monitor a maximum of 5 points. Each point must have its own anchor, rod assembly, and sensor.

Anchors: A wide variety of anchors is available, including simple groutable anchors, packer anchors, hydraulic prong anchors, and snap ring anchors.

Sensors: Both vibrating wire and Linear Potentiometers are available, with measurement ranges from 2 to 6 inches.


Settlement Sensors - MPBX

Anchors and rods are pre-assembled at the factory to save time at the site. The geotextile packer anchor will be inflated with grout when the extensometer is in place.

Positioning the MPBX head

Positioning the waterproof MPBX head which contains logger sensors, radio, and batteries. Yellow grout tubing was used to inflate the packer anchor.

Placing the traffic-rated LidLink antenna

Placing the traffic-rated LidLink antenna.