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GDSAOS – Automated Oedometer System
The Automated Oedometer System (GDSAOS) is the modern replacement for the traditional hanging weight oedometer. The GDSAOS is a self-contained unit driven by a stepper motor that can be controlled manually via a Smart Keypad, or through GDSLab when connected to a PC via USB. Note there is no requirement for a compressed air supply or manually placed weights when using the GDSAOS.
GDSCRS – Constant Rate of Strain
The Constant Rate of Strain (GDSCRS) system is primarily designed for advanced testing laboratories who want to reduce the time required to complete a consolidation test, while obtaining more information about the soil response. The GDSCRS cell fits into new and existing GDS load frames in place of a triaxial cell, or into a modified GDSAOS load frame. The load frame based one dimensional consolidation cell is capable of applying back pressure and measuring pore pressures up to 1 MPa when using the low pressure version, or up to 20 MPa when testing with the high pressure version.
GDSCTS – Consolidation Testing System
The Consolidation Testing System (GDSCTS) is a fully-automated consolidation system designed for soil. The system is based on the Rowe and Barden type consolidation cell, which is combined with GDS pressure/volume controllers from the Advanced, Standard, or Enterprise range. Two (or three when testing for permeability) of the pressure controllers link to a PC, with one used to apply vertical stress or displacement control and the other for applying back pressure. Note bender elements may be fitted within the GDSCTS cell, with an option for radial drainage also available.
GDSTAS – Triaxial Automated System
The Triaxial Automated System (GDSTAS) is a load frame based triaxial testing system. The system is configured by choosing from a range of load frames, triaxial cells, pressure controllers and software. The system can be configured as a multi-station commercial testing apparatus right through to high range rock testing at research level. If an existing triaxial system requires upgrading, parts of the GDSTAS system can be incorporated with existing equipment (including those from other manufacturers) to perform the upgrade. Typical drained and undrained shear strength parameters, such as the angle of internal friction and cohesion, can be obtained from the GDSTAS, as can the small-strain stiffness when using local strain transducers or bender elements. Permeability testing can also be performed with the addition of a third pressure/volume controller.
GDSTTS - Triaxial Testing System
The Triaxial Testing System (GDSTTS) is a fully automated triaxial testing system designed principally for stress path testing. The GDSTTS is based on the classic Bishop and Wesley type stress path triaxial cell, which applies axial and radial stresses directly to the soil specimen. Stress paths that relate to a specific construction sequence for a project may be applied to test specimens in this system, allowing the unique soil response to be observed and designs adjusted accordingly. Note as for the TAS, local strain transducers, bender elements and permeability test hardware may be included within the GDSTTS.
GDSBES - Bender Element System
The Bender Element System (GDSBES) enables measurement of the small strain shear modulus of a soil, a parameter important when conducting advanced analytical and numerical response analyses of soils. The system is unique in that it has been designed to make bender element testing reliable and easy to perform, with a signal hardware box used to generate and record propagated compressional (P) and shear (S) waves. The GDSBES system can be added as an option to most GDS laboratory test systems, as well as laboratory systems produced by other manufacturers. To date bender elements have been installed in triaxial and resonant column systems, as well as consolidation, direct simple shear systems and unconfined core holders.
GDSVIS – Virtual Infinite Stiffness Loading System
Is the premier load frame in the GDS range with load capacities or 100kN, 250kN, 400kN and 500kN. The GDSVIS load frames are designed to be stiffer than classical loading frames. This is to allow more accurate testing of stiffer specimens with less equipment compliance. Furthermore each GDSVIS is internally calibrated to allow automatic self-compensation for any remaining compliance. This type of frame is exclusive to GDS. When combined with a triaxial cell, pressure/volume controllers, and data acquisition, the GDSVIS enables typical drained and undrained shear strength parameters to be determined for use during construction projects.
ELDYN – Enterprise Level DynamicTriaxial Testing System
Is an entry level dynamic triaxial system, based on an axially-stiff load frame with a beam mounted electro-mechanical actuator. The ELDYN has been designed to fulfill the demand within the geotechnical laboratory testing industry for a lower cost, more basic dynamic triaxial testing system, yet still perform to the very advanced standards that customers expect from gds. This enables the ELDYN to provide typical drained and undrained shear strength parameters, as well as the cyclic response of soil, for use during construction project design and assessment.
DYNTTS– The Advanced Dynamic Triaxial Testing System
Is a high-end, no compromise testing apparatus combining a triaxial cell with a dynamic actuator capable of applying load, deformation and stresses up to 10Hz. The cell itself is screw-driven from an integral base unit housing the motor drive. Axial force and axial deformation are applied through the base of the cell. The system can be combined with a dynamic cell pressure actuator such that cell pressures may also be applied dynamically up to fundamental frequency of the machine (i.e. 2Hz, 5Hz or 10Hz). These features allow the DYNTTS to provide typical drained and undrained shear strength parameters, as well as the cyclic response of soil, for use during construction project design and assessment.
GDSTTA – The GDS True Triaxial Apparatus
Has the defining characteristic that, unlike conventional triaxial apparatus, all three principal stresses can be controlled independently, rather than just two in a conventional triaxial system. This allows a wider range of complex stress paths to be performed. This dynamic cyclic system is powered by advanced electro-mechanical actuators or optional hydraulic actuators and is an extremely sophisticated research tool. Vertical and one horizontal axis are loaded via the dynamic actuators (axis 1 and 2), stress control is provided for the 2nd horizontal axis, (axis 3) via cell pressure. Altogether the GDSTTA can be used to apply a wide range of stress paths to soil specimens, including those relevant to a specific construction sequence for a project.
ETAS – The Environmental Triaxial Automated System
Is a temperature controlled load frame-based triaxial testing system. Key features include, Frozen Soil Testing, Gas Hydrate Testing, High Pressure Testing and High & Low Temperature Testing. The -20oC cooling system provides ideal conditions for frozen soil testing. Its high pressure testing capability (up to 100MPa) along with low temperature provides the ideal environment for Gas Hydrate Testing. The system also has the option for a Heating only system. Such options enable the ETAS to conduct triaxial tests across a range of temperatures and confining pressures, plus provide typical drained and undrained shear strength parameters for use during construction projects.
ETTS– The Environmental Triaxial Testing System
Is a temperature controlled testing system for stress path testing. Key features include, Frozen Soil Testing, Gas Hydrate Testing, High Pressure Testing and High & Low Temperature Testing. The -20oC cooling system provides ideal conditions for frozen soil testing. Its high pressure testing capability (up to 100MPa) along with low temperature provides the ideal environment for Gas Hydrate Testing. The system also has the option for a Heating only system. Such options enable the ETAS to conduct triaxial tests across a range of temperatures and confining pressures, plus provide typical drained and undrained shear strength parameters for use during construction projects.
GDSBPS– The Back Pressure Shearbox
Has the ability to perform direct shear tests with precise back pressure control, for the recreation and measurement of realistic slope failures. The BPS range includes a saturated version (control of pore water pressure), an unsaturated version (control of both pore water and pore air pressure) and a dynamic version. While initially designed for landslide testing, the BPS offers typical shear strength parameters of soil useful for design and assessment during construction projects.
DYNBPS – The Dynamic Back Pressured Shearbox
Is used for static and dynamic direct shear testing on soil specimens with control of 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. While initially designed for landslide testing, the DYNBPS offers typical shear strength parameters of soil useful for design and assessment during construction projects.
GDSLADS – Large Automated Direct Shear System
Is an electro-mechanical direct shear testing device for large specimens, up to 300mm square or round. Different specimen sets can be used to monitor the response of geo-membranes and rock specimens under direct shear deformation. These options make the GDSLADS a useful tool when determining strength parameters required for design and assessment during construction projects.
GDSSS – The GDS Shearbase System
Is an electro-mechanical shear testing device that can be configured as either a simple shear or direct shear apparatus. The benefit of this apparatus is that the conversion between simple shear and direct shear is simple and therefore if both options are not supplied at time of build the missing option can be supplied at a later date. As direct shear and direct simple shear tests can be performed on soil specimens, the GDSSS can provide typical shear strength parameters useful for design and assessment during construction projects.
EMDCSS– Electromechanical Dynamic Cyclic Simple Shear Device
Is for simple shear testing only. It is capable of carrying out dynamic cyclic tests from small strain (0.005% shear strain amplitude) to large strain (10% shear strain amplitude), as well as extremely accurate quasi-static testing. This is the choice for a no-compromise simple shear machine with the greatest range of testing capability. The perfect choice for advanced commercial testing or academic research, allowing strength and deformation parameters required for design and assessment during construction projects to be determined.
VDDCSS – Variable Direction Dynamic Cyclic Simple Shear System
Allows simple shear to be performed in two directions, rather than the standard single direction. This is achieved by having a secondary shear actuator that acts at 90 degrees to the primary actuator. When used as a variable direction machine, the secondary shear axis can be used independently or in conjunction with the other shear axis. Therefore, simple shear may be performed in any horizontal direction. Such features allow strength and deformation parameters required for design and assessment during construction projects to be determined.
GDSIST– 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 specimen and the top-cap. Users may bond specific materials to the top-cap for testing. Such features allow the GDSIST to define interface strengths between structural and geo-materials used as part of construction projects.
GDSRCA - Resonant Column Apparatus
For many years the resonant column apparatus has been used in research and commercial laboratories to estimate values of the shear modulus, G, and damping ratio, D, for soil specimens across the small to medium strain range (< 1 %). The variation in these parameters with increasing strain magnitude allows engineers to conduct dynamic response analyses, such as those using finite element and non-linear analytical methods, which enable performance assessment of natural and engineered structures subjected to dynamic and cyclic loadings. This information is particularly useful when designing and assessing high-value construction projects.
HARRCA – Hardin Type Resonant Column Apparatus
Is a system that allows specimens to be tested in resonance while maintaining an anisotropic loading. This is achieved by a slender, thin walled loading column passing through the drive system to the top-cap. The GDS Hardin style oscillator contains an electro-magnetic drive system incorporating precision wound coils and composite sintered neodymium iron boron (NdFeB) “rare-earth” magnets. The apparatus can be mounted in a stand-alone system with an integral axial force actuator, or as a cell for integration into an existing load frame. Providing G and D curves for soil specimens, the HARRCA is particularly useful when designing and assessing high-value construction projects.
GDSHCA – Small-Strain Hollow Cylinder Apparatus
Allows for rotational displacement and torque to be applied to a hollow cylindrical specimen of soil. Using this device it is possible to control the magnitude and direction of the three principal stresses. Studies can for example be made to assess the effect of anisotropy of soil specimens, principal stress rotation, and the effect of varying intermediate principal stress. Two versions of the SS-HCA are available: A dynamic (SSHCA d), and a lower cost static (SS-HCA s) version. Each version can however be used to determine typical drained and undrained shear strength parameters for use during construction projects.
ST-RTS – Static Triaxial Rock Testing System
The StaticTriaxial Rock Testing System enables axial load application up to 2MN, with triaxial cells rated up to 100MPa used to confine test specimens of maximum 200mm diameter.
AT-RTS – Triaxial ( Active Cell) Rock Testing System
The Active Triaxial Rock Testing System allows axial load application up to 2MN via a hydraulically-actuated triaxial cell. Confining pressures up to 64MPa are available for a maximum 150mm test specimen diameter.
DT-RTS Dynamic Triaxial Rock Testing System
The Dynamic Triaxial Rock Testing System can apply axial loads of up to 1.5MN at dynamic frequencies of 20Hz and below. Dynamic loading is achieved using a servo-hydraulic actuator system.
GDSAE - Acoustic emissions transducer
The Acoustic Emissions transducers enable micro-fractures occurring within a rock specimen during testing to be recorded. The submersible transducers ma monitor fractures continuously, or only when triggered.
DGSAV - Acoustic Velocity transducers
The Acoustic Velocity transducers allow P- and S-wave velocities to be measured within a rock specimen. The transducers are mounted in the pedestal and top-cap, or in some cases the sides of the specimens.
GDSHC - Instrumented Hoek Cell
The Instrumented Hoek Cell is a highly sophisticated version of the traditional Hoek Cell, which can be fully instrumented with acoustic velocity and/or acoustic emission transducers.