Accessories for Uniaxial and Triaxial Testing

Hoek cells for triaxial test on rock sample (32-D055X/HC)
 
Uniaxial and triaxial testing systems on rocks need to be completed with suitable accessories. Testing accessories, such as Hoek cell, strain gauges, Compression/Splitting devices, shown in this section allow to perform tests covering determination of Elastic Modulus / Poisson’s ratio and strength of rock cores in uniaxial and triaxial conditions.

Hoek Cells

Used for triaxial test on rock specimen.

Standards ASTM D5407 ASTM D7012

Hoek cells for triaxial test on rock sample (32-D055X/HC)
Description
 
The Hoek triaxial cells are offered in five models of different size; each one consists of the following:
  • A cell body, complete with two quick release self sealing couplings, for the introduction of the hydraulic oil and cell pressure, and for air outlet  and saturation of the chamber respectively.
  • Lower cylinder with enlarged base and collar support that assures the vertical position of the cell even when not subjected to load.
  • Upper lower loading cap with spherical coupling.
  • One female spherical seating connected to the loading upper cap for the correct transmission of the axial load from the loading frame of the compression machine to the specimen.
  • A rubber sealing sleeve to separate the specimen from the cell fluid. Although each sleeve can be used for several tests, an order of five spare sleeves is recommended. See accessories.

Measurements of axial and radial strain are carried out with the use of electric strain gauges, both in vertical and horizontal direction, directly glued on the lateral surface of the specimen. The wiring connections are passed within the rubber sleeve  trough the cell body and loading cap. Each strain gauge must be connected to a proper device (see 82-P0398) to complete and balance the Wheatstone bridge.

The strain gauge measurements can be performed by automatic or semi automatic testing systems (see Related Products below). 

It is also recommended the use of a Specimen extruder to extrude the rock sample from its jacket thus avoiding to empty the confining fluid. (see Related Products)
Main Features
  • Various Hoek cells dimensions are available: AX, 1.5″, BX, NX and HQ types
  • Designed for high pressure capability
  • All models are fitted with two quick-release self-sealing coupling
  • One rubber sleeve is already included with the Hoek cell
  • Collar support that assures the vertical position of the cell even when not subjected to load inclued.
Products
 
 
32-D0553/HC

Hoek triaxial cell AX (30.2 mm dia. sample), one rubber sealing sleeve included.

 
32-D0554/HC

Hoek triaxial cell 1.5in (38.1 mm dia. sample), one rubber sealing sleeve included.

 
32-D0555/HC

Hoek triaxial cell BX (42.04 mm dia. sample), one rubber sealing sleeve included.

 
32-D0556/HC

Hoek triaxial cell NX (54.74 mm dia. sample), one rubber sealing sleeve included.

 
32-D0557/HC

Hoek triaxial cell HQ (63.5mm dia. sample), one rubber sealing sleeve included.

Technical Specifications
CodeD.C.D.M.A.
Reference		Specimen size
d x h [mm]		Total height
[mm]		Weight
[kg]
32-D0553/HCAX30.10×602132.50
32-D0554/HC1.5 in.38.10×752644
32-D0555/HCBX42.04×852636.50
32-D0556/HCNX54.74×10830413
32-D0557/HCHQ63.50×12731015

 

Accessories and Spare Parts
 
 
32-D0553/1

Spare sealing sleeve for AX Hoek cell 32-D0553/HC

 
32-D0554/1

Spare sealing sleeve for 1.5in Hoek cell 32-D0554/HC

 
32-D0555/1

Spare sealing sleeve for BX Hoek cell 32-D0555/HC

 
32-D0556/A
Pair of load spreader
 
32-D0556/B
Distance pad
 
32-D0556/1

Spare sealing sleeve for NX Hoek cell 32-D0556/HC

 
32-D0557/1

Spare sealing sleeve for HQ Hoek cell 32-D0557/HC

Rock Sample Extruder

Used to extrude the rock sample.

Standards ASTM D7981

Specimen extruder model 32-D0577/B
Description

 

Used to extrude the rock sample from its jacket thus avoiding to empty the confining fluid. It consists of a steel frame with a rack and pinion mechanism. Supplied without adapters. See the following table

 

Adapter set code

For specimen size

For use with cell

Weight approx. [kg]

32-D0577/1

AX

32-D0553/HC

1.7

32-D0577/2

1.5 in.

32-D0554/HC

1.7

32-D0577/3

BX

32-D0555/HC

1.5

32-D0577/4

NX

32-D0556/HC

1.5

32-D0577/5

HQ

32-D0557/HC

1.5

Products
 
 
32-D0577/B
Specimen extruder for Hoek cells series 45-D055x. Requires adaptors series 45-D0577/x
Accessories and Spare Parts
 
 
 
32-D0577/1
Extruder adapter set for specimen AX
 
32-D0577/2
Extruder adaptor set for specimen 1,5 inch
 
32-D0577/3
Extruder adaptor set for specimen bx
 
32-D0577/4
Extruder adaptor set for specimen nx

Compression/Splitting Test Device

Used for indirect tensile test (splitting test).

Standards ASTM D3967 ISRM

Compression device for indirect tensile tests on rock specimens conforming to ASTM D3967 model 32-D9032/H
Description

 

We propose two compression device models for indirect tensile test (splitting test) conforming to ASTM D3967 and to ISRM Specifications.
 
Model conforming to ASTM D3967
This apparatus, originally developed for testing in compression cement specimens, can also be used for splitting tensile test on rock disks with dimensions from dia 54 mm to 64 mm.

Models conforming to ISRM specifications
These models consist of two steel loading jaws, guiding pins and half ball bearing. Two models are available according to the specimens size: NX type (dia. 54.74 mm) and HQ type (dia. 63.5 mm).

All models can be used as an accessories with a suitable universal tester as UNIFRAME Compression / flexural machine.
See link to other products below.
 

Products
 
 
32-D9032/H

Compression /splitting device for rock specimens conforming to ASTM D3967.

 
32-D9032/HQ

ISRM Splitting device on rock specimens HQ type (dia. 63.5 mm).

 
32-D9032/NX

ISRM Splitting device on rock specimens NX type (dia. 54.74 mm).

Technical Specifications

Model conforming to ASTM D3967

  • Platens diameter: 75 mm
  • Hardness platens: 60 HRC
  • Vertical daylight: 65 mm
  • Total height: 234 mm
  • Weight: 13 kg (approx.)


Models conforming to ISRM specifications

  • Hardness jaws: 45 HRC
  • Spherical seat with a 25- mm half ball bearing
  • Top and bottom jaws with thickness and radius according to the specimens size
  • Total height: 154 mm
  • Weight: 7 kg (approx.)

 

Compression Test Device for Rock Specimens

Used for compression test according to ASTM D7012

Standards ISRM ASTM D7012

Compression device for rock specimens model 32-D9035
Description
 
This compression jig is strictly compliant to ASTM D7012 Rock core specimens Test Methods, in particular the spherical seat / compression plates / specimen diameters’ ratios fall within the prescriptions.
The Rock core should have a diameter from 54.7 mm (NX type) to 63.5 mm (HQ type).
 
It consists of a heavy duty twin-column frame, a spherically seated upper platen hold by calibrated springs and a lower platen centred on the frame base. The high stiffness structure and the high performance steel of the spherical seat make this device particularly suitable for high strength rock specimen featuring brittle properties and explosive failure.
It shall be preferably fixed on the compression machine piston head by the threaded pin included in the supply compatible with all CONTROLS compression frames / machines.

 

Main Features

 

  • Strictly compliant to ASTM D7012 Rock core specimens Test Methods
  • The Rock core shall have a diameter from 54.7 mm (NX type) to 63.5 mm (HQ type)
  • Heavy duty / high stiffness compression device
  • Max. load capacity: 1200 kN 
  • High stiffness structure and the high performance steel making this device particularly suitable for high strength rock specimen featuring brittle properties and explosive failure
  •  
Products
 
 
32-D9035

Compression device for rock core specimens with dia. from 54.7 mm (NX) to 63.5 mm (HQ) conforming to ASTM D7012.

Technical Specifications

 

  • Max. loading capacity: 1,200 kN
  • Platens dia.: 80 mm
  • Platens hardness: ≥ 58 HRC
  • Loading head stroke: 66 mm
  • Vertical clearance: 167 mm
  • Supplied with distance pieces to reduce the vertical clearance: 2 pcs. h 30 mm and 1 pc. h 22 mm
  • Overall dimensions: 249 mm dia. x 333 mm height 
  • Weight: 30 kg

Strain Gauges

They provide a very accurate electrical signal, strictly proportional to the strain of the specimen

Standards ASTM D5407 ASTM C469 ISO 6784 DIN 1048 UNI 6556 BS 1881:121 EN 13412 EN 12390-13

Rock sample fitted with 82-P0390 strain gauges
Description

 

They provide a very accurate electrical signal, strictly proportional to the strain of the specimen submitted to load application, for determining the Elastic Modulus and strength characteristics as alternative to the Compressometer-Extensometers 55-C0222/G which can be used only on samples  with min dia.75mm and min height 160mm. They can be applied to the specimen surface by a special Adhesive-Catalyst agent and other accessories all included in the 82-P0399/C Strain gauge application kit.
Up to 4 strain gauges ¼ bridge, and up to 8 ½ bridge, can be directly connected by one or two interfaces 82-P0398  to to our automatic control consoles  MCC or Automax Multitest which are suitable for cyclic loading and automatic determination of the Modulus of Elasticity.
Strain gauges can also be connected, by one or two interfaces 82-P0398, to a suitable data logger as, for example, our model 82-P9008, when the load application on the specimen is performed with Automatic compression testers as, for example the AUTOMAX PRO and PILOT PRO models. In this case, one of the channels of the Datalog 82-P9008 should be used for the load signal coming from an additional pressure transducer with selecting valve fitted to the compression tester.
Please get in touch with our technicians for complete information and service.  

Products
 
 
82-P0396
Strain gauge 120mm gauge length. (pack of 10)
 
82-P0390
Strain gauge 9,53 mm gauge length. (pack of 10)
 
82-P0391
Strain gauge 20 mm gauge length. (pack of 10)
 
82-P0392
Strain gauge 30 mm gauge length. (pack of 10)
 
82-P0393
Strain gauge 60 mm gauge length. (pack of 10)
Technical specifications
 
 
Models 82-P0390    P0391    P0392   P0393   P0396   
Grid width mm0,90,91,22,311
Gauge length mm10203060120
Resistance  ohm120120120120120
Bridge¼¼¼¼¼
No. of gauges per package   1010101010
Accessories and Spare Parts
 
 
 
82-P0398
Compensation device for up to 4 Wheatstone bridgeswith 1/4 or 1/2 bridge setup
 
82-P0399/C
Strain gauge application kit including: conditioner, neutralizer, acetone, tweezer, adhesive with catalyst agent, 100 m of bipolar cable, solder, soldering iron, scalpels, scissors,duct tape, sellotape, sandpaper and carrying case.
 
82-P0399/P22
Bonding and catalyst agent to glue the strain gauges
 
82-P0399/1
Connecting terminals. 50 pairs sheet

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