The MDDCSS also allows the application of a confining pressure to the sample. The sample carriages are encased within an acrylic pressure cell. The application of confining pressure also allows back pressure to be applied to test specimens. This allows specimens to be back-pressure saturated, with excess pore pressures directly recorded during simple shear tests. When used as a variable direction machine, the secondary shear axis can be used independently of the other shear axis or in conjunction, therefore simple shear may be performed in any horizontal direction.

Key features	Benefits to the user
Test control:	Test control allows specification of amplitude of shear stress/strain as well as direction.
Direction of shear and pattern of shear rotation from zero degrees can be defined:	Constant at zero degrees.  Rotate from zero degrees at a constant rate. Cycles from zero degrees plus or minus x degrees with period in seconds. Angles relative to zero e.g. 0, 10, 20, 30 etc. Definition of waveform by datum/common point, amplitude, controlling parameter and frequency.
Teflon coated rings:	K-zero conditions ensured by use of 1.1mm high, low-friction, PTFE coated rings.
6 Axis Loadcell:	Highly accurate internally compensated measurement of all loads.
Independent axis control:	Each axis can be load or displacement controlled.
Local strain LVDT’s for both shear directions:	Highly accurate strain measurement.
Pressure control:	Confining pressure up to 1MPa  is applied by water and controlled using a  Pneumatic Controller (GDSPPC) through a direct air/water interface within the cell. A second pressure controller is used to apply back pressure.
Pore water pressure transducer:	Highly accurate measurement of pore water pressure in all stages of testing.