Controls Group Dynamic electromechanical triaxial systems DYNATRIAX EmS Dynamic electromechanical triaxial systems DYNATRIAX EmS
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Soil mechanics

Dynamic electromechanical triaxial systems DYNATRIAX EmS

  • Download:
BS 1377:7 | ASTM D2850 | ASTM D4767 | BS 1377:8 | ASTM D5311 | ASTM D7181 | ASTM D3999 | AASHTO T0307
Main features
  • Electromechanical Servoactuation, no need of compressed air or hydraulic power supply for the vertical force 
  • Capability to perform Static (effective stress and stress path), Dynamic and Unsaturated soil triaxial tests
  • Maximum dynamic load: 15 kN
  • Maximum static load: 10 kN
  • Triple-axes closed loop control of axial load/displacement, cell and back pressure
  • Automatic compensation of cell/back pressure during dynamic stage
  • Operating frequency more than 10 Hz (depending on test conditions)
  • Complete automation of all test stages using an high sensitivity closed loop PID feedback
  • Options available for bender elements testing and for local strain transducers
  • Standard and user defuned wave shapes which can mimic the real in situ measurements (earthquakes)
  • Test set-up by unique programmable multi-stage procedure. When a test is running, it is possible to access all parameters to expand and modify the stages as per the response of the specimen 
  • Manual and automatic emergency shut off function
  • Multitasking, user-friendly Windows-based software pre-installed on the PC
  • Extra-accurate transducers calibration adopting linear or polynomial regression or multi-coefficient linearization
General description
General description
Dynatriax EmS benefits from CONTROLS Group new EmS "Electromechanical Servoactuation" technology.
EmS technology is environmentally friendly and clean to operate, requiring no compressed air or hydraulic oil. It offer excellent reliability, accurate testing and lower maintenance requirements. The intuitive design ensures it can be quickly and easily maintained, only requiring regular lubrication.
The system controls three closed-loop axes:
  • Axial load/displacement
  • Cell pressure up to 1000 kPa
  • Back pressure up to 1000 kPa
The base system includes:
  • Reaction frame
    • Robust 2-columns construction, stiff and compact
  • Electromechanical vertical load application
    • high performance motorized actuator, 15 kN capacity, backlash free and noiseless
    • sophisticated PID closed-loop control, ensuring load is reached fast, smoothly and accurately and then maintained with high level of accuracy. The submersible load cell delivers high accuracy from the lowest values
  • Data acquisition, process and control
The CDC manages up to 3 closed loop axes (axial load/displacement, cell and back pressure) with an effective loop rate of 10 kHz and performs the test completely automatically including the on/off valves for the drainage line and for the air supply to the triaxial cell. It is linked to the PC via LAN/Ethernet link (1 Gbit/s) and comes with 16 transducer ports (real resolution 16 bit).
  • PID control
An extremely efficient algorithm with larger gain ranges gives enhanced sensitivity, making it easier to tune the system and achieving a more accurate wave shapes.
Recently added features include manual and automatic amplitude control which compensate for small changes that may occupr in the system during cycling, ensuring that the required peaks are consistently reached. The improved tuning panel, with its more user-friendly interface, provdes all the tools necessary to optimize the system control during static and cyclic test stages. 
More +

Technical specifications

  • Maximum dynamic load: 15 kN
  • Maximum static load: 10 kN
  • Maximum vertical travel: 50 mm (different travels available on request)
  • Maximum testing frequency: more than 10 Hz (depending on testing conditions)
  • Volume change measurement: 100 cc volume change device with automatic flow inversion
  • Max sample diameter: 100 mm
  • Maximum confining pressure: 1000 kPa
  • Maximum back pressure: 1000 kPa
  • Close loop control frequency: 10 kHz
  • Input channels: 16 - Real resolution 16 bits
  • Voltage:  208-230 V, 50-60 Hz, 1 ph  or  110 V, 60 Hz, 1 ph

Ordering info

Dynatriax EmS - Automatically PC controlled dynamic triaxial system with 15 kN Electromechanical Servoactuation. Supplied complete with PC, CDCtriax control and 16 channels data acquisition unit and software. 208-220V, 50-60 Hz, 1ph 

Dynatriax EmS - Automatically PC controlled dynamic triaxial system with 15 kN Electromechanical Servoactuation. Supplied complete with PC, CDCtriax control and 16 channels data acquisition unit and software. 110V, 60 Hz, 1ph 


Triaxial cells
Triaxial cells for advanced applications
Double wall triaxial cells for unsaturated tests

Submersible load cell

5 kN capacity submersible load cell for accurate measurement, not affected by the friction of the ram and the cell pressure

10 kN capacity submersible load cell for accurate measurement, not affected by the friction of the ram and the cell pressure

25 kN capacity submersible load cell for accurate measurement, not affected by the friction of the ram and the cell pressure

Transducer - LVDT

Axial displacement transducer +/- 25 mm

Pore pressure

Pressure transducer 0-10 bar for pore pressure measurement

De-airing block

Volume change

Automatic volume change apparatus, 100 cc

Additional Information

Typical configuration of a dynamic system
Cyclic system and load frame
DYNATRIAX - Dynamic Triaxial System 50kN-5kN 31-WF70E06 1
Submersible Load Cell 25 kN 31-WF7119 1
Axial Displacement Transd LVDT 31-WF7121 1
Pore Pressure Transducer 1000kPa 28-WF6300 3
de-airing blok 28-WF6310 1
Automatic volume change 29-WF4412 1
70mm sample triaxial cell and accessories
Triaxial cell 28-WF4070 1
Base pedestal 28-WF4071/7 1
Vacuum top cap 28-WF4072/AV 1
Pair of porous stone 28-WF4074 1
Rubber membrane 28-WF4075 2
O-ring 28-WF4076 1
Suction device 28-WF4071/A 1
O-ring placing tool 28-WF4071/B 1
2 part split former 28-WF4071/D 1
Filter drains 28-WF4071/E 2
Filter discs 28-WF4071/F 1
Hand sampler 28-WF4071/G 1
2 part split mould with vacuum attachment 28-WF4071/H 1
Bender elements option
bender elements 70mm dia 28-WF4078/B 1
Wave generator  28-WF4190 1
Advanced kit for Triaxial cell model WF4070 28-WF4070/ADV 1
Pressure system
Bladder air/water interfa 28-WF4320 2
Triaxial panel two way pressure 28-WF4335 1
Air Compressor 10 bar 145 86-D2015 1
Air treatment unit 28-WF2016/2 1
De airing system
Air drying unit 86-D2005 1
Silica gel dessicant with indicator 86-D0819 1
De airing tank, 23lt capacity 28-WF4221/A 1
Valve panel por use 28-WF4225 1
Portable vacuum pump. 28-WF2001 1
Rubber tube dia 6,5 x 12mm 28-WF2064 1

Multitasking, user-friendly Windows-based software is pre-installed on the computer supplied 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 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 mechanical actuator
Any or all of the above stages can be performed in “Automatic mode” where the test parameters are entered at the beginning of the test or stage and the software takes control applying the required stages and parameters.
  • 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 wave shapes
  • Transducer limits
- An air shut-off valve can be programmed setting the user defined limits
  • Calibration
- Digital calibration using linear or polynomial regression or multi-coefficient linearization
- Transducer verification option




Unsaturated soil testing package.
The package includes the additional servo-valve for air pressure control, prressure transducer and the software to automatically perform the test stages using the axis translation method:
  • Simultaneous and independent control of air pressure, pore water pressure and axial stress
  • Performance of consolidation, saturation soil water curve and shear stages
  • Test data recording for each stage
Triaxial cell and test accessories have to be ordered separately.


Resilient modulus determination on compacted samples.
This package provides software for performing the test according to AASHTO T307 standard, two 10 mm displacement transducers, and mounting brackets to fit the transducers to the piston of the triaxial cell.
The software includes:
  • Two standard sequences of dynamic cyclic stress and static confining stress for subgrade soils and base/sub-base materials
  • The possibility to set up customized sequences that the user can save and replicate automatically
  • Continuous monitoring in real time of recorded and processed data of each single sequence