Dynamic Back Pressure Shearbox

Product Code : DYNBPS

The Dynamic Back Pressured Shearbox (DYNBPS) is used for static and dynamic direct shear testing on soil specimens with control of sample pore pressures. The control of pore pressure during direct shear testing allows real-world situations to be modelled in the laboratory.

This dynamic version of the device allows a landslide to be modelled as it quickly gains velocity after the initial moment of failure. Cyclic direct shear testing is also possible while still controlling and measuring pore pressure.

Further Information:
Key features Benefits to the user
Electro-mechanical actuators: Designed for long life and highly accurate position control. Unlike pneumatic actuators this type of actuator is suitable for carrying out small strain testing, long term creep tests and dynamic tests up to 5Hz.
Realistic modelling: The DYNBPS provides a realistic model of many real-world cyclic and seismic geotechnical problems, such as slope stability and earthquake loading.
Interchangeable internal load cells: For increasing accuracy and resolution on soft soils.
Closed-loop control: For shear force/displacement and normal force/displacement.
Shear gap: Manually set-able from outside the pressure vessel whilst under pressure.
Balanced rams: Allows cost effective static pressure controllers to be used for back pressure with minimal pressure fluctuations during dynamic tests.
Axial Force Accuracy

24bit (i.e. <0.4N for 10kN load cell, <1.5N for 40kN load cell)

Computer Interface



1200mm (H) x 500mm (L) X 770mm (W),

Load Range (kN)

Axial force 25, Shear force 10

Operating Frequency (Hz)



240V or 110V 50/60Hz 1 ph

Pressure Range (MPa)

2 back pressure

Resolution of Measurement and Control


Sample Sizes

50mm square, 75mm square. Sample height = 20mm.

Weight Approx (kg)