Dynamic Triaxial Systems 1000 kPa

Standards

ASTM D 5311

Description

Dynatriax systems are ideal for commercial and research laboratories for the following applications: Liquefaction potential, Strength degradation due to cyclic loading, Shear modulus and damping ratio, resilient modulus, Effects of blasting in mines and quarries, Effect of ocean waves on costal and off shore structures.

DYNATRIAX apparatus is a computer controlled servo-pneumatic systems, designed to perform the static and dynamic stages of a triaxial test. The systems manage three closed loop axis:

• Vertical load/displacement:
  • -up to ± 25 mm (± 5 kN actuator)
  • -up to ± 15 mm (± 14 kN actuator)
• Cell pressure up to 1000 kPa
• Back pressure up to 1000 kPa

The base systems include Tritech 50 or Tritech 100 Triaxial load frame, the Actuator, and the CDC Compact Dynamic Controller for data acquisition, control and processing. We propose three versions

• NG-WF7005 with 50 kN load frame and ±5 kN actuator
• NG-WF7006 with 50 kN load frame and ±14 kN actuator
• NG-WF7010 with 100 kN load frame and ±5 kN actuator
• NG-WF7015 with 100 kN load frame and ±14 kN actuator

New Dynatriax PID control

The DynaTriax has been upgraded with a new and improved PID control. A more efficient algorithm with larger gain ranges gives enhanced sensitivity, making it easier to tune the system and achieving a more accurate waveshape.

New features include manual and automatic amplitude controls which compensate for small changes that may occur in the system during cycling, ensuring that the required peak and valley levels are consistently maintained.

The improved tuning panel, with its more user-friendly interface, provides all the tools necessary to optimize system control during static and cyclic test stages.

Dynamic Triaxial Systems Main Features

FLEXIBILITY

• Three axis closed loop control for axial load or displacement, cell and back pressure
• Operating frequency up to 10 Hz
• Two dynamic load/displacement options:
• - Up to ±25 mm with ±5 kN actuator
• - Up to ±15 mm with ±14 kN actuator
• Capability to perform Static (effective stress and stress path), Dynamic and Unsaturated soil triaxial tests
• Available upgrade for Bender element testing and Local strain measurement

RELIABILITY

• Standard and user defined wave shapes also derived from in situ measurements (from violent earthquakes to sedate ocean waves)
• Complete test automation of all test stages using an high sensitivity closed loop P.I.D. feedback (up to 10 Hz)
• Automatic compensation of cell/back pressure during dynamic stage
• Transducer calibration and verification management by software
• Manual and automatic Emergency air shut-off function

MODULARITY

• Test set-up by unique programmable Multi stage test procedure: during the test run, access to all controls to expand and modify the stages according to the response of the soil specimen
• Designed to easily Integrate existing static systems

Dynamic Triaxial Systems Technical Specifications

Tritech 50 or Tritech 100 Triaxial load frames

The Tritech digital loading frames feature a microprocessor controlled drive system, specifically designed to perform both static and dynamic tests.

• Static load capacity: 50 or 100 kN
• Static vertical displacement: up to 100 mm (machine travel)

Actuators

The double acting pneumatic actuators are digitally controlled and includes an integrated LVDT displacement transducer to control the position and the displacement of the piston during the test.

• Dynamic load capacity: ±5 kN or ±14 kN
• Dynamic vertical displacement ±25 or ±15 mm
• Operating frequency: up to 10 Hz (depending on test conditions)
• Maximum servo-valve frequency: 70 Hz
• Min. air supply: 800 kPa

CDC Compact Dynamic Controller

The unit manages the three closed loop axis (vertical load/displacement, cell and back pressure) with a control loop rate of 10 Hz. It provides the automatic control of the system and drives the servo-valve units of the three axis and two on/off valves, one connected to the drainage line and one connected to the air main supply of the triaxial cell. The CDC communicates with the PC through an Ethernet communication link (1 Gbit/s). The CDC has sixteen transducer input channels using 16 bit ADC.

Software

Multitasking, user-friendly Windows-based software is pre-installed on the computer provided with the system. The software provides control of the following utilities and stages of a cyclic triaxial test:

• Saturation
  • Cell pressure increments with B value check
  • Back pressure increments with volume change measurement
  • Cell and back pressure ramp
• Consolidation
  • Isotropic consolidation with continuous volume change measurement
• Ko consolidation

Vertical displacement loading with sample diameter control using either:

• Direct measurement by radial belt with on-sample transducers
• Measurement of sample volume change and height
• Stress path
  • Horizontal and Vertical Stress
  • s, t (average stress and shear stress)
  • p, q (mean normal stress and deviator stress)
  • Vertical stress using strain control
• Monotonic shear
  • Strain controlled static shear stage, drained or undrained
  • Loading in compression or extension, using the vertical actuator or the Tritech

Any or all of the above stages can be performed in "Automatic mode" where the test parameters are entered at the start of the test or stage and the software takes control of managing the stages using predefined criteria.

• Cyclic loading
  • ASTM D5311 Load Controlled Cyclic Strength
  • ASTM D3999 Load Controlled Modulus & Damping
  • ASTM D3999 Displacement Controlled Modulus & Damping
  • Non Standard Single or multi cycle test
  • User defined or imported Waveshape
• Transducer limits
  • An air shut-off valve can be programmed to be activated using defined channel limits
• Calibration
  • Digital calibration using linear fit, polynomial fit or linearization
  • Transducer verification option