Settlement Gauges

MAGNET EXTENSOMETER (BRS)

The magnet extensometer is a system, based on British Building Research (BRS) techniques, for measuring either settlement or heave at various depths in soil, embankments, earthfill dams and dikes. The system consists of an access tube with external corrugate pipe, magnet rings, as well as a telescopic bottom section with datum ring and suspension head. Magnet rings (targets) are positioned externally to the access tube, and then placed in the ground where movements may occur. Magnet rings move together with the surrounding soil along the axis of the access tube. Readings are obtained with a portable unit through the reed switch probe that is lowered through the access tube. Comparison of surveys taken over time provides profiles of ground settlement or heave.

Technical Specifications
System Components

C121 PORTABLE READOUT
MAGNET DETECTOR PROBE UNIT

HORIZONTAL DISPLACEMENT MAGNET SYSTEM
Magnet system can be installed horizontally to measure horizontal ground movements.

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T-REX REMOVABLE EXTENSOMETER

T-REX is a removable extensometer that has been designed for incremental measurements along the axis of inclinometer casing equipped with targets. The T-REX probe is equipped with a contactless magnetostrictive linear transducer. Operating cable, placement rods, portable readout and T-REX analyzer software are provided. Utilization of the Archimede portable readout is suitable for tracking readings with T-REX probes. Through the USB port, the measurements can be easily transferred to a PC for data management. T-REX analyzer software allows the operator to computer displacement measurements line-wise per meter of distance, both in vertical and horizontal installations.

Technical Specifications
T-REX extensometer offers several advantages:
- wide measuring range (±100mm displacement every meter) which allows applications either  in soil or rock
- fully compatible with Sisgeo inclinometer operating cable, connector and readout
- no-mechanical contact between probe and targets
- combined with inclinometer measurements permits 3-D deformation borehole profile

PORTABLE READOUT
Measurements are performed by Archimede dataloggers equipped with external battery pack (Product Code 0CDL012EXBP0). The battery pack is sealed in a water-resistant case, which is connected to the portable readout unit when the operator performs measurement functions.

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DEX IN-PLACE EXTENSOMETERS

DEX extensometers are used in conjunction with flush-coupled ABS inclinometer casings for automatic monitoring of settlement or heave. Strings of DEX extensometers are joined together with stainless steel wire or bars. DEX probes can be placed at different depths where the settlement occurs with reference points at the top or bottom of the casing. DEX-S model is also equipped with biaxial tilt sensors; it permits 3-D borehole profile monitoring. ADK-100 datalogger equipped with GSM module provides automatic monitoring of unattended locations.

Technical Specifications
DEX PROBE

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DIFFERENTIAL SETTLEMENT MONITORING (DSM) SYSTEMS

Sisgeo has developed the DSM System for automatic and continuous long-term monitoring of differential settlements or heaves of buildings and structures. The DSM structure system consists of a series of DSM tank-gauges interconnected by a small hydraulic tube to a reference tank, which is located on a firm point away from the area that is going to be monitored. The hydraulic tube is filled with a de-aired mixture of 50% glycerine (99%) and 50% water. This mix is usually supplied by Sisgeo and is chemically inert to all components in the system. The measurement of fluid level inside each DSM tank indicates the elevation difference between the sensors and the reference tank.

Technical Specifications
DSM LEVEL GAUGE
(Product code 0D422M08000)

DSM systems are very sensitive to temperature changes. Accurate measurements require that temperatures be monitored at sensor locations. Data is processed using “Fieldstat” software.
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HYDROSTATIC PROFILE GAUGE (PROFILER)

Profiler is a hydrostatic profile gauge designed for settlement or heave monitoring beneath embankments or foundations. The system consists of a settlement probe equipped with a high sensitive pressure transducer connected by a liquid-filled tube to a reservoir. The Profiler probe is pulled – meter by meter – through a HDPE pipe buried in fill, embankment, etc. The liquid tube is wrapped on a reel. The transducer measures the profile of the pipe relative to the reservoir located on a tripod mounted on stable ground. On the reel face panel, the LCD displays direct readings in millimeters.

Technical Specifications
PROFILER PROBE
(Product code 0D5HPG33100)

PROFILER CABLE
(Product code 0WE206KE000)
Profiler cable includes electrical cable and liquid tube encapsulated in a common PVC external jacket.

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DSM SETTLEMENT GAUGES

The measured soil settlement of ground or embankments is of primary importance for monitoring the structural stability during construction works. Two types of DSM settlement gauges are available: D422R model for embankment and D422F model for borehole. Depending on the type of application, the settlement gauges are installed in different configurations, linked together by a hydraulic line to a reference gauge and connected to an automatic data acquisition system. The operating principle is based on the pressure variation caused by the change in height of a column of liquid. Subsequent height variations occurring between the datum point and the measuring points cause proportional variations of the hydraulic level at each settlement gauge.

Technical Specifications
EMBANKMENT GAUGES
(Product code 0D422R00000)

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