GDS True Triaxial Apparatus

Product Code : GDSTTA

The GDS True Triaxial Apparatus (GDSTTA) has the defining characteristic that, unlike conventional triaxial apparatus, all three principal stresses can be controlled independently, rather than just two in a conventional triaxial system. This allows a wider range of complex stress paths to be performed. This dynamic cyclic system is powered by advanced electro-mechanical actuators. 

Vertical and one horizontal axis are loaded via the dynamic actuators (axis 1 and 2), stress control is provided for the 2nd horizontal axis, (axis 3) via cell pressure.

Further Information:
Key features Benefits to the user
Stress or strain is applied to a 75mm x 75mm x 150mm sample independently on three axes: Two pairs of matched dynamic rams for axes 1 and 2, and a confining fluid provides pressure for the 3rd axis on load readings.
Ram specification: Each ram has its own internal submersible load cell and displacement transducer to ensure friction effects are minimised.
Electro-mechanical actuators as standard: Electro-mechanical actuators provide an easier to use and environmentally friendly solution for accurate testing to 5Hz. Electro-mechanical actuators do not require a hydraulic power pack to be present, hence no requirement to service a powerpack or to protect system users from noise generated by a powerpack.
Sample preparation: Full sample preparation equipment for cohesive and non-cohesive samples is provided with the system including a specially designed soil lathe for producing cuboidal samples.


Axial Force Accuracy

0.1% FRO

Axial Force Accuracy

Dependent on range

Computer Interface


Data Acquisition

16 Bit


2250mm tall, 1750mm wide, 550mm deep

Displacement Accuracy

0.1% FRO

Displacement Range

50mm per actuator (100mm per axis)

Displacement Resolution


Load Range (kN)

20 (Electro-mechanical)

Operating Frequency (Hz)



3-Phase Power supply required: 380V-415V, 50Hz/60Hz. Maximum current capacity 64 Amp. Note: GDS provides a 3-phase power socket with neutral and earth for wall mounting.

Pressure Accuracy

Dependent on chosen pressure controller

Pressure Range (MPa)


Sample Sizes

75 x 75 x 150mm