Behaviour of Joints

32-D0548/A: Detail of the shear box apparatus fitted with 5 digital gauges (4 vertical and 1 horizontal)

Rock joints originate from geological failures occurring when a break in the rock mass continuity along with no visible displacement has occurred. From a rock mechanics point of view, the discontinuities are characterized by a lower mechanical strength than the original rock matrix and require the following detailed test investigations:

• shear strength of the joint performed with the rock shear box apparatus,
• tilt test performed with the tilt test apparatus,
• surface roughness of the joint performed with the profilometer (Barton comb).

Download our new Buyer's Guide for Rock Shear Box Apparatus

 

Rock Shear Box Apparatus

Used for determining the strength and slope stability of rock.

Standards ASTM D5607

32-D0548/A: complete digital rock shear apparatus
Description
 
 
This apparatus was originally developed at Imperial college, London, by Professor E. Hoek. It is a simple and practical method of determining the strength and slope stability of rock, both in the field and in the laboratory. The apparatus consists of a shear box designed to accept samples not larger than 115×125 mm, or alternatively cores up to 102 mm dia. The shear box consists of two halves, the upper being connected to two rams for reversible shearing action and the lower connected to a ram for normal load application. The loads are recorded by Bourdon tube load gauges or by pressure transducers (in this case external datalogger is needed).
The normal loading system is complete with an adjustable low friction pressure maintainer to absorb volume changes of the specimen during the shearing action and to ensure a constant vertical stress.

Two versions are available:
  • Basic model. It is supplied complete with: 5 digital gauges 25×0.001 mm (4 vertical and 1 horizontal); 2 mould formers; 2 hand operated pumps for lateral and vertical load fitted with Bourdon gauges. The pump for vertical load is fitted with a pressure maintainer to assure uniform load during the test.
     
  • Electronic model. It is supplied complete with; 5 potentiometric transducers with 25mm travel (4 vertical and 1 horizontal); 2 mould formers; 2 hand operated pumps for lateral and vertical load fitted with Bourdon gauges; 2 pressure transducers for the direct acquisition of the load values. The pump for vertical load is fitted with a pressure maintainer to assure uniform load during the test.
     

Displacement and load readings shall be acquired by suitable datalogger that has to be add as accessory. Two versions can be used to complete the testing configuration: standard model with dedicated display suitable for laboratory use or with battery operated model for on-site use. For more info please refer to Releted Products below and Accessories section.

The high alumina cement for the cementation of the sample is not included and have to be ordered separately. See Accessories
Main Features

 

  • Shear box made in aluminium alloy
  • Maximun axial and shear load capacity: 50 kN
  • Reversable shear action with 48 mm stroke
  • Double version available: analogic and electronic
  • Data processing template available as accessory for the digital version
  • 2 mould formers included in the testing configuration 
Products
 
 
32-D0548/A

Rock shear apparatus to ASTM D5607. 

 
32-D0548/D

Electronic rock shear apparatus to ASTM D5607.  Datalogger NOT included. 

Technical Specifications

 

  • Max. axial and shear load capacity (for both models): 50 kN
  • Manometers range (for both models): 50 kN x 1 kN
  • Displacement reading (for Basic model): 5 digital gauges 25×0.001 mm 
  • Displacement reading (for Electronic model): 5 potentiometric transducers with 25mm travel 
  • Max. sample dimensions: up to dia. 102 mm (for core specimens) and 115 mm x 125 mm (for prism specimens)
  • Overall dimensions (loading frame only): 460x250x600 mm
  • Weight approx.: 45 kg
Accessories and Spare Parts
 
 
32-D0548/8
Mould former
 
32-D0548/9
High alumina cement. 50 kg bag.
 
32-P0070/6
MS Excel template for Direct Shear Strength Tests of Rock specimens according ASTM D5607
 
82-P9008/ELT
Set of four cables for connecting load cells, pressure transducers, strain gauges, LDT / LVDT / potentiometric type displacement transducers to DATALOG 8 (82-P9008) and GEODATALOG 8 ( 30-WF6008)
 
82-P9008/SOF

DATACOMM 2 data acquisition software and LAN cablefor PC connection of DATALOG 8 (82-P9008, P9008/F) – Up to 8 datalogger (total 64 channels) can be connected to a single PC creating a modular network (LAN hub is required) 

 
82-P9008

DATALOG 8, 8 channels stand alone multipurpose data logger. 110-230V / 50-60Hz / 1 Ph.

 
82-P9008/F

DATALOG 8, 8 channels multipurpose data logger, battery operated and with rigid carrying case suitable for use on field. 110-230V / 50-60Hz / 1 Ph.

Joint Roughness Coefficient Test Device

Used for calculating the JRC of a rock or joint.

32-B0096
Description

 

It is used to calculate the JRC of a rock or joint. The device consists of an adjustable inclined plane, on which the rock sample (100 mm max dia.) is placed, separated along the surface where the roughness is to be measured. Then the plane is slowly tilted until sliding of the upper part of the sample on the lower one occurs. From the measured inclination angle it is possible to evaluate the roughness index.

  • Inclination angle: 0 to 50°
  • Overall dimensions: 265x170x260 mm
  • Weight approx.: 4 kg
Products
 
 
32-B0096
Apparatus for measurement of the joint roughness coefficient (Tilt Test)

Profilometers (Barton Comb)

Used for measurement of the roughness profile of rock samples.

32-D0566
Description

 

Used for measurement of the roughness profile of rock samples.

Products
 
 
32-D0566
Profilometer (Barton comb) 300 mm length
 
32-D0566/A
Profilometer (Barton comb) 150 mm length
Technical Specifications
  • Lenght: 150 (32-D0566/A) or 300 (32-D0566) mm
  • Height: 85 (32-D0566/A) or 150 (32-D0566 mm

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