Inclinometers

Five segments fit in a carton roughly 64 x 64 x 64 cm weighing under 2.13 kg. You can ship it overnight, carry it in a car trunk, or strap it to an ATV. Same logistics as the Vertical GeoFlex.

Yes. DGSI offers placement rods (sensorless dummy segments) that install at the end of the string, so you only instrument the specific zone of interest rather than the full casing length. This is the horizontal equivalent of the sensorless nodes offered for the top of the Vertical GeoFlex string.

Either 70 mm or 85 mm diameter inclinometer casing. The casing is installed horizontally through the zone of interest. The system spans that zone, so when the ground moves, the casing moves with it and changes the inclination of the nodes inside.

Up to 200 nodes in 85 mm casing, or up to 50 nodes in 70 mm casing — same as the Vertical GeoFlex.

It’s suited for monitoring ground movement beneath or adjacent to structures where vertical settlement is the concern. Typical applications include:

• Embankment settlement in roadways, levees, and retaining walls
• Monitoring beneath large diameter storage tanks
• Ground movement from tunnel construction
• Landslide early warning above dams, highways, and railroads

The Vertical GeoFlex is better suited where lateral displacement in a borehole is the measurement goal (deep excavations, retaining wall deformation, etc.).

The Horizontal GeoFlex uses the same MEMS sensor nodes as the Vertical GeoFlex but is installed in horizontal casing rather than a vertical borehole. Instead of measuring lateral movement in a borehole, it measures settlement and heave along a horizontal plane. Nodes are still spaced at 50 cm or 2 ft and cumulative deflections produce a profile of the casing. Changes in that profile indicate settlement or upward movement (heave).

The GeoFlex does not allow for more movement, as both systems will perform until the signal cable  is pulled apart or cut. However, the shorter gauge lengths of the GeoFlex system do increase the reliability of the data once shearing begins. With the typical longer gauge of the IPIs, the shearing is more likely to bend the gauge rod making the displacement results questionable.

Presentation of the data will be exactly the same (with the exception of the higher density of readings for GeoFlex – 2 feet vs 5 or 10 feet). Both systems are plotted as displacement vs. depth. For Horizontal GeoFlex installations, data is plotted as settlement or heave versus horizontal distance rather than depth.”

Both GeoFlex and IPIs can be installed on the same Campbell data logger. The GeoFlex uses an RS485 bus and the IPIs use an analog (RS232) bus.

Multiple GeoFlex strings can be connected to the same Campbell data logger. The number of strings depends on the logger you are using. The CR6 and CR1000X can each handle two strings but do not require the MD-485 module as they have native RS-485 communication.

The IPI sensors have the flexibility of having variable length gauge tubes. They are most typically installed with 5 or 10 feet gauge tubes, but any length can be used down to about 1.5 feet. The GeoFlex system has a 2 feet gauge length at a cost of about the same as 10 feet gauge tubes for the IPIs, thus you achieve a higher density of readings over the same distance for the same cost.

Both the IPIs and the GeoFlex systems can be removed and replaced. Please note that a new baseline will need to be set once the system has been reinstalled. Due to the lighter weight of the system, the GeoFlex is generally considered easier to remove and replace.

Yes. The standard GeoFlex segment consists of five 2 feet nodes (10 feet total) that are connected electrically via a waterproof Seacon connector and mechanically via a pinned universal joint. Once the project is complete the system can be removed and broken down into its 10 feet segments (provided that the shear isn’t so great that they can’t be removed from the casing). Those segments can be used on another project and because each node is addressable, it doesn’t matter in what order the segments are installed on the next project. The Horizontal GeoFlex uses the same durable nodes and connectors with the same redeployment benefit on future projects

Campbell Scientific (CR6 or CR1000Xe can log two strings directly; CRE350 can log two strings) It should be noted that some of these layouts may preclude the reading of other sensor types and you should contact your DGSI representative if you have a more complicated layout.