The volume change gauges are designed to measure changes in volume of specimen, measured in terms of the change in the volume of the cell, during a triaxial shear test. The apparatus consists of an outer acrylic tube and an inner graduated glass burette held between two aluminum blocks. Manifolds are provided to enable water, either to pass through the tubes during measurements or to go direct to the cell when no measurements are required. The indicator is coloured paraffin (not supplied with the unit). The volume changes are measured by the downward movement of paraffin/water inter-face in tube burette. In the twin burette gauges the manifolds allows the reversal of flow of water, this enabling continuous measurements when testing large diameter samples. The gauges are designed for a working pressure of 1000kpa.
(Higher pressure optional)
Specially designed for research purpose, he volume changes of the order of 0.003 cc can be measured during slow triaxial tests. It consists of a long capillary tubing about 2 mm inside diameter, fixed along a scale.
The ends of the tubing connected through mercury traps to a valve manifold from which the direction of fluid flow in the capillary tubing can be reversed without affecting the precision of the test. Directional control valve with flow reversing facility and by-pasing the volume change unit is provided as standard.
Capacity of gauge is about 6 cc per cycle and can withstand a pressure of 21 kg/cm².
The unit is highly sensitive and accurate for the measurement of volume change. It has a frictionless rolling bellowfram seal coupled to submersible type displacement sensor. Sensitivity of the system is 0.01ml. Change in volume is directly displayed on digital display system in engineering units.
HEICO DigiTriax is totally automated stresspath system for soils and conforms to the test requirements of IS-2720 (Part-XII) and BS-1377. All the modules namely load frame, confining pressure, back pressure, pore pressure or volume change are totally controlled by the dedicated computer. Once the specimen is assembled in the triaxial cell, required parameters like strain rate, confining pressure and back pressure are programmed through the computer. Controlling and data acquisition is supported by window based software. It can perform tests under the following conditions:
Detailed specifications of the individual modules are given as under:
It is a two-pillar type load frame that can accommodate triaxial cell up to 100mm dia specimen. Rate of strain is precisely controlled through micro stepper motor of fractional horsepower operating at 220volts, 50 Hz single phase supply (other voltages optional).
Limit switches and L.E.D are incorporated in the hardware to arrest the travel limits and also to indicate the direction of movement (up/down).
Selection could be made from wide range of triaxial cells, they are light weight cells. Transfer bar (loading ram) passes through linear bearing making it almost friction free.
Base has four no-volume change valves one each for back pressure/pore pressure, confining pressure and top drainage.