Geotechnical equipment for Laboratory

Geotechnical equipment for Laboratory

Basic Features: 
GDS Instruments was founded in England in 1979, then known as "Geotechnical Digital Systems". The company's first product was the computer controlled triaxial testing system based on the "Bishop & Wesley'' stress path cell. The cell was linked to the computer via microprocessor controlled screw pumps driven by stepping motors.

Triaxial Testing

GDS are World leaders in Static Triaxial Testing Systems, Dynamic Cyclic Triaxial Testing Systems and Unsaturated Triaxial Testing. In addition to complete systems we also supply individual components such as pressure controllers, specialist transducers, unsaturated soil testing upgrades or bespoke units supplied to the customers specification.


What is it? The GDS Triaxial Automated System (GDSTAS) is a load frame-based triaxial testing system which may be configured exactly to the customers specification and budget. Using the GDS range of load frames, triaxial cells, pressure systems and the GDSLAB software, the basic system can be configured for low cost multi-station commercial testing right through to high range rock testing at research level. Using GDSLAB with optional software modules, GDSTAS can run advanced tests such as stress paths, slow cyclic and K0, all under PC control. GDS pressure/volume controllers are used to apply cell pressure, back pressure, and also to measure the sample volume change resolved to 1cc. Using the GDS pressure/volume controller there is no requirement for the 'old type' bladder volume change gauges.

The GDSLAB software suite allows the user complete flexibility on how the system can be setup with multiple stations allowable. This system can be configured using any GDS devices, from a 50kN to 1000kN load frame and from a 500kPa to 150MPa pressure controller. On-sample transducers, bender elements and unsaturated testing can all be added, as you would expect from a GDS system.


What are its uses?

The operator chooses the type of test from a test menu (eg UU, C-U, multi-stage, stress path etc) and then enters the test parameters (of cell pressure, back pressure, testing rate and so on) and test termination conditions. The test then proceeds automatically with all test data being saved to a file. On-line graphics are presented with up to three graphs displayed together with a block of current live test data. Tests can proceed overnight and during weekends and holidays. To enable spot-verification, all electronic measurements may be duplicated by mechanical gauges. The computer directly controls the cell pressure, back pressure and testing rate. In addition to logging these parameters to the PC hard drive, the computer also logs axial displacement, axial load, pore pressure and volume change. Of course, additional transducers may be easily configured and logged during the test.


What is it?

GDS Unsaturated Triaxial Testing of Soil (UNSAT) is an extension to traditional triaxial testing in that soils from above the water table may be tested under conditions approaching the in-situ stress state and degree of saturation or partial saturation. All features and methods described in the GDS unsat upgrade datasheet can be used to upgrade GDS triaxial testing systems to enable the testing of unsaturated soil, or existing triaxial equipment from other manufacturers may be modified. The required changes to upgrade a typical GDS triaxial testing system consists of software and hardware elements. Optional elements are made available to add further rigour to the test procedures if this is required (for example mid-plane suction probe, atmospheric pressure transducer and local measurement of strain).


The GDS Advantage

- Choice of different methods to suit your testing requirements and budget

- Developed in conjunction with HKUST, specialists in unsaturated soil testing

- Methods may be ‘mixed and matched' to create a custom system

- Due to GDS's knowledge of many different unsaturated test methods, we can objectively advise customers on the best method for their test requirements. We are not limited to a single solution.

- GDS has more than 50 customers worldwide using it's unsaturated soil testing systems and software.



GDS manufacture two types of electromechanical cyclic triaxial testing systems. An advanced Electromechanical Dynamic Cyclic Triaxial Testing System (DYNTTS). Which, is a combined triaxial cell and dynamic actuator, and a Enterprise Level Dynamic Cyclic Triaxial Testing system (ELDYN) which, has been designed to fulfil the demand within the geotechnical laboratory testing industry for a dynamic cyclic triaxial testing system, at a lower cost.

What is it?

The GDS Enterprise Level Dynamic triaxial testing system has been designed to fulfil the demand within the geotechnical laboratory testing industry for a dynamic triaxial testing system, with a lower cost. ELDyn provides a route to allow cyclic loading of triaxial samples under either load or strain control while monitoring the effects on the specimen pore pressure.