Innovative Geotechnical Instrumentation

Mahanagar, Lucknow, Uttar Pradesh

IGI Model IG 1000 junction cum switch box is used to terminate four core cables of maximum 10 sensors from the site at a convenient safe location and connect to a multi core cable through which data may be transferred to the control room / data logger/Data acquisition system or computer. Different options of cable glands may be used depending upon the type of cable. The box conforms to IP 65 ingress protection class

IGI Model IG-1003 tiltmeters are used to measure Tilt in structures like high rise buildings, old monuments, dams, retaining walls and slopes.

• Typical Applications
• Studying the effect of excavation on adjacent structure.
• Prediction of slope failure and remediation.
• Protection of monuments and old buildings while making metro tunnels under cities.
• Measuring tilt of Dam body in order to monitor parameters and ensure Dam Safety.
• Monitoring effect of water table on old buildings and towers.
• Monitoring stabilization measures such as pressure grouting.
• Evaluating performance of structures like beams, Bridges and Dams under load.
• Studying convergence and other movements in tunnels.
• Monitoring deflection and deformation in retaining walls.

Shotcrete stress cells are designed to measure radial and tangential stresses in shotcrete linings in tunnels. This instrument provides the most significant data for determining thickness and stability of shotcrete lining in NATM (New Austrian Tunneling method). These cells consist of two rectangular stainless steel plates, welded together around their periphery and spaced apart by a narrow cavity filled with de-aired fluid and connected by a stainless steel tubing to a pressure transducer. The cell has a length of re-pressurising tube to restore contact between concrete and cell after the concrete has set. Provision of gas discharge tube protects the sensor against surge and lightning.

Innovative series IG1100/1200 strain gauges have a unique integral magnet design which incorporates a miniature magnet coil assembly positioned inside a stainless steel tube of diameter 15mm. The same tube has a high tensile strength, heat-treated and tempered steel wire stretched between two end blocks. The wire is sealed in the tube by means of a set of double O-rings. This feature, when compared to conventional externally mounted magnet design has the following advantages:

• Robust anstallation and minimum protection needed after installation.

Externally mounted magnet assembly on the other hand is prone to corrosion as it is made in two halves, which are externally clamped on to the tube. This does not ensure proper sealing at the joint. Thus water can seep and with time cause corrosion on the magnet, resulting in failure.

Embedment type strain gauges are provided with built in stainless steel flanges while the groutable and arc weldable type have the same design. By the use of appropriate type of mounting blocks, the same strain gauge can be arc welded on to the steel structures such as tunnel linings and supports or grouted or epoxy bonded on the surface of concrete structures.

To take care of space limitation, for vertical measurement of strain across thin concrete lining, embedment strain gauges with 55mm gauge length are used. For eg. on pavements.Provision of gas discharge tube protects the sensor against surge and lightning.

Accessories:

• 5 position rosette for mounting strain gauge at different angles and in different planes.
• No-stress container to evaluate strain produced due to factors other than load.
• Brackets for arc welding on structures or grouting.
• 6 position junction box to terminate strain gauges installed on Rosette.

Innovative series IG-1400/1500 piezometers are used to measure ground water elevations and pore water pressures in bore holes, embankments, concrete structures, pipe- lines, wells, mines, tunnels etc. Model IG-1501 has the filter replaced with a threaded adapter to permit it to be coupled directly to pressure lines. Provision of gas discharge tube protects the sensor against surge and lightning.

Typical Applications

• Controlling water pressure during consolidation by continuous monitoring.
• Prediction of slope failure and remediation.
• Design for lateral earth pressures.
• Design for uplift pressures and buoyancy.
• Monitor seepage, determine phreatic line and verify models of flow.
• Monitor surface water run-off.
• Monitor rate and direction of flow of contaminated water.
• Monitor encroachment of salt water into fresh water acquifiers.

Outstanding features

• Unprecedented sensitivity, long term stability and reliability.
• Isolation of the sensor assembly from the effects of total stresses acting on the body of the piezometer.
• Robust and sturdy construction.
• Slim-line design.
• Corrosion resistant option available for coastal applications.
• Provision of thermistor for temperature measurement.
• Provision of gas discharge tube for lightening and surge protection.
• Suitable for remote reading, scanning and Data logging.
• No effect of cable length on performance of the sensor.

IGI Bore Hole stress meter consists of a capsule having length 40mm and diameter 30mm. It has a hollow, steel cylindrical body having a vibrating wire tensioned across one diameter. The perpendicular diameter is wedged tightly inside a diamond drilled bore hole in the rock/ coal by a wedge platen assembly.

A custom designed tool is used for installing and prestressing the stress meter at the required depth and orientation inside the bore-hole.

The tool positions the stress meter inside a predrilled hole at the required depth and fixes it by the help of a wedge and platen assembly. The capsule is pre-stressed by the help of the same tool.

Bore hole stress meter is used specifically for monitoring stress changes in underground mines, hard rock and concrete structures. It also serves as a load cell when incorporated between steel members. Provision of gas discharge tube protects the sensor against surge and lightning.

General applications include

• In mines; roof, wall and pillar.
• Around tunnels and within linings.
• In underground storage chambers.
• In concrete structures.
• In foundations bearing plates and between girders.

Push-In type Displacement Transducer/ Crack meter Model IG-2002 & Perimetric Joint meter Model IG-2002 XYZ

The model IG2002 crackmeter consists of a spring loaded, compression type vibrating wire displacement transducer and two installation brackets. One mounting bracket supports the displacement transducer while the other is anchored across the joint on to the reference surface. The springloaded shaft of the displacement transducer is always in contact with the reference surface at the other side of the crack. The sliding rod senses the movement between the two anchors and gives a frequency output which is read by the indicator.

For measurement in three orthogonal directions IG2002XYZ or perimetric joint meter is used. This version has three sets of displacement transducer assemblies installed across the crack in three mutually perpendicular directions. Free movement of the sliding shaft in all directions ensures accuracy of measurement.

Temperature meters are used to measure internal temperature in concrete structures, soil or water. Temperature monitoring plays a vital role during curing of concrete. It is also used for interpretation and analysis of temperature related stress and volume changes in dams, study of soil and rock temperature near liquid gas storage tanks, and water temperature in reservoirs and bore holes.

Temperature gauges have a simple yet robust and sturdy construction, which provides a complete waterproofing and high degree of protection from humid and corrosive environmental conditions. These may either be embedded or surface mounted. Embedment is simple and orientation is not critical. Provision of gas discharge tube protects the sensor against surge and lightning.

These are used for measurement of total pressure in earth fills and embankments, at the interface of two different materials or measurement of stress in concrete. Also used for measurement of contact pressures on retaining walls, piles and tunnel linings.

These cells consist of circular stainless steel plates, welded together around their periphery and spaced apart by a narrow cavity filled with de-aired fluid and connected by a stainless steel tubing to a pressure transducer. Provision of gas discharge tube protects the sensor against surge and lightning.

Dimension

• 200mm dia pad .
• 20mm diax 145mm length pressure transducer.
• 6mm dia connecting tube.

IGI model IG 1000S is mainly used to teminate 5 strain gauges installed on a rosette and one No stress strain installed along side the strain gauge. A single multi-core cable takes data from junction box to the control room.

Displacement Transducer Model IG-1002

Innovative displacement transducer model IG-1002 is ideal for use in single and mutipoint bore hole extensometers. Its unique slimline design is very convenient for multipoint bore hole extensometers as a number of sensors may be installed within a single hole. The sensor also finds application in soil extensometers and roof convergence measurement. It may even be used in perimetric joint meters. Provision of gas discharge tube protects the sensor against surge and lightning.

These are rugged and compact sensors used to measure loads in tiebacks, rockbolts, struts or tunnel supports. These are designed to meet the demands of the severe and adverse environmental conditions usually associated with construction or mining activities. To monitor tensile load, the load cell assembly has an annular configuration to enable the passage of anchor through it. To monitor compressive load, the load cell is provided with integral solid centre platens mounted on the end faces of the load sensing element. The load cells have three or six vibrating wire sensors to nullify the effect of eccentricity and an average of the readings of all gauges is equal to the applied load.

Typical Applications

• The measurement and control of loading in foundation anchors and rock bolts.
• Tension in cable anchors and struts.
• Load between structural beam and top of piles.
• Load between tunnel lining segments.
• Proof loading and pullout tests on trial anchors.
• Correlation of data obtained from bore hole extensometer

Piezometer : Water level gauge Model IG 1402 with 20m integral cable and vent tube

Model IG-1402 Automatic Water Level Recorder is designed for accurate, remote monitoring of ground water level in a reservoir/ borehole, coastal and inland waters, ports, wells and rivers. It can also be used for recording water level in canals, open channels, sumps and underground and overhead tanks/ sumps.

It essentially consists of a vibrating wire pressure sensor provided with a vent tube of required length running parallel to the sensor cable. The vent tube and cable are routed through a protective tube to a Digital read out unit, for displaying the water level in its engineering units. A special cylindrical filter with conical tip is provided to give more surface area to the sensor. The filter is fixed on to the sensor body through a threaded connector which may easily be removed for saturation. Option of disc filter is also available.

Outstanding features

Unprecedented sensitivity, long term stability and reliability.

Isolation of the sensor assembly from the effects of total stresses acting on the body of the piezometer.

• Robust and sturdy construction.
• Slim-line design.
• Corrosion resistant option available for coastal applications.
• Provision of thermistor for temperature measurement.
• Provision of gas discharge tube for lightening and surge protection.
• Suitable for remote reading, scanning and Data logging.
• No effect of cable length on performance of the sensor.

DIGIlog -1 is a single channel datalogger cum display unit, which can be used for continuous data recording at site for a single bore hole. This is used with IGI level transducer /Piezometer model IG 1402. Data can be recorded at pre -set time intervals in meter of water column with date and time. The stored data can be transferred to a PC/Laptop through a pendrive.

• Water level at any moment can also be observed on the instrument panel by pressing a button.
• The data logger can be installed near the borehole on a pillar or in a control room.
• Housing is IP-65 weather proof enclosure.
• It stores 8000 readings after which it starts re-writing from the first reading.

These are used at the base and crown of steel reinforcement ribs in tunnels and under ground structures.

Typical Applications

• The measurement and control of loading in foundation anchors and rock bolts.
• Tension in cable anchors and struts.
• Load between structural beam and top of piles.
• Load between tunnel lining segments.
• Proof loading and pullout tests on trial anchors.
• Correlation of data obtained from bore hole extensometer

Digiview1001 is a general purpose, Hand held, Multi channel vibrating wire readout unit. It can read the data of over 7000 water level sensors and store the same against the channel number. Data has to be taken by carrying the readout to the junction box at the mouth of the hole and connecting the 4 wires of the level sensor to the clips on the readout unit. On selecting the channel no. Which has been programmed for that bore hole, the user can read the water level at that particular instant. He can even store the date and time stamped data by selecting the store option. The stored data may be transferred to a PC/ Laptop through a USB cord.

These are vibrating wire load cells provided with a swivelling top plate and fixed bottom plate. Number of vibrating wire sensors is generally three. These are used in mines for monitoring load during and after excavation. A beam is provided between the swivel top of the load cell and the roof. The load cell is positioned at the floor along with the convergence meter. Provision of gas discharge tube protects the sensor against surge and lightning.

Typical Applications

• The measurement and control of loading in foundation anchors and rock bolts.
• Tension in cable anchors and struts.
• Load between structural beam and top of piles.
• Load between tunnel lining segments.
• Proof loading and pullout tests on trial anchors.
• Correlation of data obtained from bore hole extensometer

IGI Model IG 2000 cable splicing kit is used to connect the cable which is integral with the sensor to the armoured /Jelly filled heavy duty cable used on site. Cable splicing is done on site by a special technique to ensure safety of the joint and both ends are marked with the specific sensor details. A special insulating potting compound secures the joint inside the splicing kit. The cable is then routed through trenches to the final location or secured safely in a trench covered with sand during the construction activity.