Geotechnical Instruments

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Geokon, Inc., The World Leader in Vibrating Wire Technology, is one of the world's leading designers and manufacturers of a broad range of high quality Geotechnical Instrumentation.

Instruments manufactured by Geokon are used primarily for monitoring the safety and stability of civil and mining structures such as dams, tunnels, mine openings, foundations, piles, embankments, retaining walls, slopes, subway systems, underground powerhouses, bridges, culverts, pipelines, shafts, slurry wall excavations, braced excavations, tiebacks, nuclear waste repositories, ground water remediation schemes and the like.

Product Datasheets

Strain Gages & Strainmeters

Vibrating wire strain gauges for geotechnical monitoring and engineering. Product Highlight: The Model 3900 Embedment Strain Gauge is designed for the measurement of dynamic strains in concrete structures, earth fills and soils. It comprises a full bridge strain gauged proving ring coupled, between two flanges, with a spring and shaft. When the flanges move relative to one another, the tension in the spring changes and hence the strain in the proving ring. A PVC tube serves as a protective housing and holds the gauge at the desired initial tension.

Jointmeters, Strandmeters, Crackmeters, Convergence Meters & Displacement Meters

Product Highlight: The Model 4450 Displacement Transducer provides remote readout capability for borehole extensometers. They are particularly useful where other types of vibrating wire sensors are used and/or for installations where long cable runs are required. The Model 4450 can also be installed between borehole anchors, in conjunction with the requisite length connecting rod, to provide a permanent, in-place incremental extensometer.

Extensometers, Anchors, Readout Instruments & Sensors

Product Highlight: The Model A-9 Retrievable Extensometer (Patent No. 5,585,555) is designed to measure deformations in boreholes in rock, concrete, and other construction materials. The device can be used in pile load teststudies, plate jacking tests and virtually any application where a hole can be drilled or a pipe can be cast into the structure being studied. The system features adjustable gage lengths, rapid and simple installation/removal and high accuracy using a variety of transducers including Vibrating Wire and DCDT’s. Adapters for use in square tubing are also available.

Piezometers, Pressure Transducers & Weir Monitors

Product Highlight: The Model 4500H and 4500HH Pressure Transducers*are supplied with 1⁄4-18 female NPT (4500H) and 
7⁄16-20 60 degree female medium pressure (4500HH) fittings to permit the transducer to be coupled directly into hydraulic or pneumatic pressure lines. Other pipe thread sizes are also available.

Earth Pressure Cells, Concrete Stress Cells, & Load Cells

Product Highlight: The standard Borehole Pressure Cell (BPC) is used to measure rock stress changes and is designed to be grouted inside a borehole. The BPC is manufactured from two steel plates welded together around their periphery. The plates are deformed into a “dog bone” configuration so that they can be expanded easily, without damage to the welds. Hydraulic oil fills the space between the two plates and a high-pressure stainless steel tube connects the plates to a stainless steel pressure gage and/or a pressure transducer.

Inclinometers (MEMS), Tiltmeters (MEMS) & Casing

Product Highlight: The Model GK-604D Digital Inclinometer System is delivered in its entirety and includes a Model 6100D Digital Inclinometer Probe, a reel-mounted cable and a Field PC. The Model 6100D contains electronics to convert the analog voltage into a digital signal, which is transmitted by the control cable to the cable reel containing the Interface, which communicates wirelessly with the Model FPC-2 Field PC. A Digital Compass is built into the Inclinometer Probe to correct the inclinometer data sets for any twist (or spiraling) in the inclinometer casings. The spiral survey data is presented on (and stored in) the same FPC-2 Field PC used for taking inclinometer readings. An optional 12 volt electric cable reel system is available, which can provide substantial time savings when surveying deep inclinometer casings.

Readout Boxes, Dataloggers, Software & Digital Signal Processors

Product Highlight: The Model GK-404 Vibrating Wire Readout is a portable, low-power, handheld unit that is capable of running for more than 20 hours continuously on two AA batteries. It is designed for the readout of all GEOKON vibrating wire gages and transducers, and is capable of displaying the reading in either digits, frequency (Hz), period (µs), or microstrain (µε). The GK-404 also displays the temperature of the transducer (embedded thermistor) with a resolution of 0.1°C.

Borehole Pressure Cells, Stressmeters & Borehole Deformation Gages

Product Highlight: The standard Borehole Pressure Cell (BPC) is used to measure rock stress changes and is designed to be grouted inside a borehole. The BPC is manufactured from two steel plates welded together around their periphery. The plates are deformed into a “dog bone” configuration so that they can be expanded easily, without damage to the welds. Hydraulic oil fills the space between the two plates and a high-pressure stainless steel tube connects the plates to a stainless steel pressure gage and/or a pressure transducer.

DeAerators, Temperature Gages & Cables

Product Highlight: The Model 3800 Thermistor Probe consists of an interchangeable thermistor bead mounted inside a rugged PVC (Model 3800-1) or stainless steel (Model 3800-2, 3800HT) housing. They are used for remote readings, such as measuring hydration and cooling temperatures in placement of mass concrete.

 

Case Histories