Stress path triaxial and uniaxial automatic test system

Main Features

  • Advanced testing system suitable for extremely variable materials, from soft sandstone to high-strength marbles
  • Determination of Elastic modulus, Poisson’s ratio and strength characteristics of rock specimens under uniaxial and triaxial conditions
  • Automatic performance of triaxial tests with combined control of axial load and confining pressure
  • Multiple failure stages triaxial test (stress – path mode) carried out automatically, the entire failure path is derived from a single specimen including post-peak softening phase
  • Also suitable for load, stress, displacement and strain-controlled testing on concrete, fibre-reinforced and shotcrete specimens (with the relevant options and accessories)
  • Fully programmable test procedures including axial load and confining pressure levels and combinations
  • Integrated data acquisition and results elaboration including failure envelope plotting
  • Extremely flexible system ideal for research purposes

Links: Geo-Con Flyer / Brochure / Data Sheet

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Description

CONTROLS Stress path triaxial and uniaxial automatic test system is designed to test various materials, from soft sandstone to high strength marbles.
The test system comprehends:

ADVANTEST ROCK, servo-hydraulic control console for axial load application in conformity with the relevant Standards. Includes a dedicated software for triaxial testing which also controls the SERCOMP ROCK and automatically determines the sample failure envelope. 
The ADVANTEST ROCK performs loading-unloading ramps and can also be used for load/stress/displacement/strain controlled testing on concrete, fiber reinforced concrete, shotcrete, etc. (with the suitable options and accessories)

SERCOMP ROCK. Servo-hydraulic control console for confining pressure control into the Hoek cell (triaxial test only). It runs as a remotely controlled unit, fully operated by the Advantest Rock software.
Includes 4 additional channels for strain / displacement transducers.

ADVANCED SOFTWARE: ADVANTEST ROCK and SERCOMP ROCK are linked to a single PC for data acquisition and results elaboration.

The overall test information and readings are always available on the PC screen:

  • Axial load and sample strength
  • Hoek cell confining pressure
  • Sample deformation measured by strain gauges and external displacement transducers

Plus any additional load/strain/displacement readings from external transducers that may be useful for research purposes.

HIGH STIFFNESS COMPRESSION FRAME to be selected from the wide CONTROLS product range, conforming to the size of the sample and the expected strength.
Due to the typical high strength and fragility of rocks we recommend high capacity test frame (4000kN or 5000kN capacity).

HOEK CELL: various models for different sample size are available: from EX type with dia. 21.46 mm up to HQ type for core with dia. 63.5 mm.

Triaxial test is carried out automatically with multiple failure stages: from a single specimen it is possible to plot the entire failure envelope,

Test procedure

  • Axial and horizontal stresses are increased hysotropically up to a defined level
  • Cell pressure is maintained constant and axial stress is increased
  • When the sample approximates maximum strength, the cell pressure is automatically increased up to a defined level
  • Cell pressure is again maintained constant and axial stress is increased
  • When the sample again approximates maximum strength, the cell pressure is further increased
  • The above procedure is automatically repeated several times
  • Maximum peak strength is reached and, in case of displacement control, the test is continued (softening phase)
  • Cell pressure is reduced in steps and, for each step, the residual strength is measured
  • All the maximum peak loads are plotted against corresponding values of cell pressure building the complete failure path.

For a typical configuration of an Automatic triaxial test system see Additional information.

Technical Specs

ADVANTEST 9 ROCK
Hydraulic group

  • Max. working pressure: 700 bar
  • Max. oil delivery: 2 lpm at low pressure, 0.7 lpm at high pressure
  • 4 hydraulic ports for connection of test frames
  • Flow control via servo-controlled proportional valve
  • Oil cooling system with forced ventilation
  • 4 ON/OFF valves with electronic control

Hardware and on board software

  • Maximum resolution: 1/524,000 divisions
  • 8 input channels:
  • 4 for load sensors (load cells or pressure transducers)
  • 4 for displacement transducers (potentiometric, LVDT amplified or analogical) and for deformation transducers (clip gauge, strain gauge).
  • Electrical characteristics of the conditioners:
  • VEXC: from 0.5 to 10 V DC selected via software
  • Single/dual ended input
  • Input signal from -2.5 to +2.5 V DC
  • Zero and gain adjustable via software
  • Data acquisition synchronized on all channels
  • 8 analogical outputs corresponding to each channel for possible use of an external data acquisition system
  • Test execution with control of:
  • Load/specific load
  • Displacement
  • Strain
  • Auto-diagnostic system including oil level and oil filter obstructed
  • 320×240 pixel display
  • Storage of multiple calibration curves for immediate connection of different sensors.
  • Low frequency Dynamic tests: max. frequency 0.1 Hz (depending on the wave amplitude)

Phisical specifications

  • Power rating 750 W
  • Voltage: 230V, 50Hz, 1ph or 230V, 60Hz, ph or 110V, 60Hz, 1ph
  • Dimensions (lxwxh): 470x410x1000 mm
  • Weight approx.: 120 kg, excluding PC and printer

SERCOMP 7 ROCK

  • Max. working pressure: 700 bar
  • Max oil delivery: 0.7 l/min
  • Flow control via servo-controlled proportional valve
  • 4 additional channels for strain / displacement transducers
  • Power rating: 750 W
  • Dimensions (LxWxH): 470x410x1000 mm
  • Weight approx.: 120 kg

PC and SOFTWARE

  • PC and printer of the latest generation
  • Remotely control the entire system. Display graphical and numerical data including multi-plot mode, e.g. 3 different deformation curves with respect to a single time axis
  • Execute tests and sequences of steps/cycles programmable by the user
  • Print out test reports
  • Allow the real time modification of the test parameters during the test execution, including active control channel
  • Language selection: English, French, Spanish, Italian, plus another language which can be created by the user

Accessories

Please refer to the links to other products below for more technical and commercial info about:

  • Compression frames
  • PC cabinet
  • Hoek cell and sample extruder
  • Strain gauges for uniaxial and triaxial tests
  • Compression device for uniaxial tests

 

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