Interface Shear Tester

Product Code : GDSIST

The Interface Shear Tester is a CRS consolidation cell with the additional ability that the base pedestal may infinitely rotate. The internal load cell measures both the axial force on the specimen as well as the torque generated.

The system is designed to test the shear interface between the sample and the top-cap.  Customers may bond specific materials to the top-cap for testing.

Further Information:

Discover more shear testing equipment for soil testing.

Key features Benefits to the user
Interface friction studies: The most common uses for the GDSIST include studies of interface friction, for example between geomembranes, pipline footings and natural materials.
Load cells: Low range load cell for accurate low stress testing of axial load and torque.
Stainless steel: Available in stainless steel for corrosive sample testing.
Internal submersible load cell: This allows the user to measure friction between the sample and material without errors being introduced by the seal friction on the ram.
Compact: Small laboratory footprint.
GDS force actuators for axial stress: Accurate electro-mechanical control of axial force and displacement with keypad + display for local control.
Actuators

1 off vertical, 1 off torsional

Axial Force Accuracy

±0.1%/RC

Axial/Torque Force Range

1kN/10Nm, 2.5kN/25Nm, 5kN/50Nm, 5kN/200Nm

Computer Interface

USB

Load Range (kN)

5

Power

Table top frame: 240V, Control systems: 100-240V~1.6A MAX

Pressure Range (MPa)

1

Sample Sizes

70, 60, 63.5, 67, x 22mm

  • Larger Range Load cells available.

 

Tests supported by the Interface Shear Tester, shear testing equipment for soil testing :-

Axial Compression

An axial compression test determines the behaviour of geo-materials when the major load is applied in the axial direction. The specimen load and displacement is recorded while the specimen is compressed. Please note: Some apparatus may require additional components or software modules to perform certain tests.

Constant rate of Loading (CRL) Consolidation

Provides a controlled ramp of load while the back pressure is maintained. There is also the option to limit the rate of strain if a specified hydraulic gradient across the sample is exceeded.

Constant rate of strain (CRS) Consolidation

Provides a controlled ramp of strain while the back pressure is maintained. There is also the option to limit the rate of strain if a specified hydraulic gradient across the sample is exceeded.

Cyclic Testing, Slow

Slow cyclic testing may be performed on all GDS triaxial testing apparatus with the appropriate software modules.  The speed the cycles can be applied is determined by the performance of the system.  A standard load frame generally only used for quasi-static testing can perform cyclic testing with periods of around 5 minutes when coupled with GDSLAB control and data acquisition software. Please note: Some apparatus may require additional components or software modules to perform certain tests.

Cyclic loading of samples under either load or strain

Cyclic loading refers to the repeated loading of a sample.  All GDS systems can imply this loading either under load control, or under strain (displacement) control.  Load control will be via feedback from the load cell and displacement control will be via the feedback from the displacement transducer.  Load and displacement control can be performed by all GDS system.  The speed of the cyclic loading depends on the frequency performance (i.e. the dynamic performance) of the system in question.  Dynamic stress control is possible, but only available on the most advanced GDS dynamic because of the additional processing required to calculate the sample area during the cycles.  Please note: Some apparatus may require additional components or software modules to perform certain tests.

K0 (K-Zero)

Kzero conditions (or specifically the coefficient of earth pressure at rest) in the context of laboratory testing are where a sample is required to be loaded whilst keeping the area of the sample a constant.  Kzero conditions are maintained in a n oedometer by design due to the radial constraint, however in an oedometer the radial stress cannot be measured therefore the K-zero condition is not measureable.  A Kzero test in a triaxial cell allows Kzero conditions to be applied and measured. The Kzero module allows you to run two tests. 

  • Test 1: Kzero using ramp RADIAL STRESS with direct radial transducer measurement: Uses a direct reading of the specimen diameter to enable the test control to maintain zero diameter change.
  • Test 2: Kzero using ramp RADIAL STRESS with back volume change measurement: Uses the change in volume of the specimen to calculate a theoretical new specimen height thus ensuring the diameter change remains zero.

Please note: Some apparatus may require additional components or software modules to perform certain tests.

Load Control (Static)

Enables application of load to a specimen for tens of seconds or more, and at frequencies less than 0.1 Hz during cyclic loading. Please note: Some apparatus may require additional components or software modules to perform certain tests.

Multi-stage Testing

The procedure for conventional triaxial tests requires three separate soil specimens to be sheared to failure under different confining pressures so that Mohr-Coulomb failure envelope can be determined and soil shear strength parameters can be obtained. An alternative procedure is the multi-stage triaxial compression test, which requires only one soil specimen to be tested at three stages of shearing with different confining pressures.


There main advantages of multi stage soil testing is the requirement for fewer soil specimens, as well as reduced testing time.  The advantage of performing the test with 3 separate samples is that if one of the samples is unsatisfactory (perhaps due to sample disturbance for example) then it is likely to be noticed when the Mohr circles are plotted, whereas this could remain unnoticed in the multi stage test. Please note: Some apparatus may require additional components or software modules to perform certain tests.

Oedometer / Consolidation

Uses a datalogger to take settlement readings from a hanging weight oedometer system.  Alternatively, GDS produces an automated oedometer which completely automates one dimensional consolidation testing.

Quasi-Static (low speed/creep) Tests

Quasi-static refers to slow speed tests.  Creep tests require accurate displacements to be measurable whilst a continuous, sometimes long term loading is accurately applied. Please note: Some apparatus may require additional components or software modules to perform certain tests.

RAMP and CYCLE pressure or volume change (Saturation Ramp)

Saturation ramp allows you to independently increase or decrease the Cell Pressure and the Back Pressure. The saturation ramp is used to steadily change the pressures in the system either keeping a constant effective stress or change to a desired effective stress.

Static Displacement

A static displacement test involves applying and maintaining a constant displacement to the specimen. The load response can subsequently be observed. Alternatively this may refer to cases where a displacement, which may vary, is applied to a specimen for tens of seconds or more. Please note: Some apparatus may require additional components or software modules to perform certain tests

Static Load

A static load test involves applying and maintaining a constant load on the specimen. The displacement response can subsequently be observed. Alternatively this may refer to cases where a load, which may vary, is applied to a specimen for tens of seconds or more. Please note: Some apparatus may require additional components or software modules to perform certain tests.

Stepped Loading

Stepped Loading provides a means to increase the specimen axial load, whilst maintaining a constant back pressure and measuring the back (pore) volume change. Please note: Some apparatus may require additional components or software modules to perform certain tests.

Standards for the Interface Shear Tester, shear testing equipment for soil testing :-