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Hoek cells and sample extruder

ASTM D5407 | ASTM D7012
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
General description
General description
The Hoek triaxial cells are offered in five models of different size; each one consists of the following: (please refer to the drawing)
  • A cell body (1), 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.
  • Two end caps (2), screwed into the cylindrical cell body.
  • Upper (3) and lower loading caps (4) with spherical coupling.
  • Two female spherical seating (5) connected to the loading caps (3) and (4) for the correct transmission of the axial load from the loading frame of the compression machine to the specimen.
  • A rubber sealing sleeve (6) 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.
Note: Hoek cell HQ type model 32-D0557 is provided with an upper spherical seat and a lower supporting collar that assures the vertical position of the cell even when not subjected to load. For this reason holding device code 32-D0556/H is not required with this model.

Measurements of axial and radial strain are carried out with the use of electric strain gauges (7), 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). 
The cell pressure and saturation pressure for permeability tests are carried out by the use of appropriate equipment (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 accessories.
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Technical specifications

Code D.C.D.M.A.
Specimen size
d x h [mm]
Total height
32-D0553 AX 30.10x60 213 2.50
32-D0554 1.5 in. 38.10x75 264 4
32-D0555 BX 42.04x85 263 6.50
32-D0556 NX 54.74x100 304 13
32-D0557 HQ 63.50x127 310 15

Ordering info

Hoek cell, AX, for dia. 30.10x60 mm

Hoek cell, 1.5 in., for dia. 38.10x75 mm

Hoek cell, BX, for dia. 42.04x85 mm

Hoek cell, NX, for dia. 54.74x100 mm

Hoek cell, HQ, for dia. 63.50x127 mm


Accessories for compression test

Pair of load spreader for uniform load distribution

Distance pad to reduce the vertical clearance of the compression machine

Hoek cell holder compatible with Hoek cell codes 32-D0553, 32-D0554,32-D0555 and 32-D0556. Not required for Hoek cell HQ type code 32-D0557
Rock sample extruder

Specimen extruder for Hoek cells series 32-D055x, requires adaptors series 32-D0577/x.
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.

Extruder adapters set, comprising two support cell body and shaft head.

Adapter set code For specimen size For use with cell Weight approx. [kg]
32-D0577/1 AX 32-D0553 1.7
32-D0577/2 1.5 in. 32-D0554 1.7
32-D0577/3 BX 32-D0555 1.5
32-D0577/4 NX 32-D0556 1.5
32-D0577/5 HQ 32-D0557 1.5
Spare rubber sleeves

Spare rubber sleeve, AX, for specimen dia. 30.10x60 mm

Spare rubber sleeve, 1.5 in. for specimen dia. 38.10x75 mm

Spare rubber sleeve, BX, for specimen dia. 42.04x85 mm

Spare rubber sleeve, NX, for specimen dia. 54.74x100 mm

Spare rubber sleeve, HQ, for specimen dia. 63.50x127 mm