Large Size Dynamic Triaxial Apparatus
Multi-Directional Dynamic Simple Shear Apparatus
Large Size Dynamic Hollow Cylinder Apparatus
Small-Strain Measurement Units (Bender Elements, LDT, Proximity Sensors)
Geophysical Field Testing Equipments
Central CO2 and Air Pressure Supply and Air Dryer Unit
Central Cooling System and Air Compressor
Large Size Dynamic Triaxial Apparatus
Dynamic triaxial device is a special tool that is most commonly used for measurement of dynamic soil properties at high strain levels as well as liquefaction testing of saturated soils. Owing to its special features, our device is capable to conduct various stress-controlled or strain-controlled tests on cylindrical specimens with different diameter and sizes. For this purpose a servo hydraulic closed loop controlling system is used that can precisely monitor and control parameters such as stress, strain, pressures and displacement during the test. A high-precision data acquisition system provides a fast measuring system to record desired data during the experiment. Using a special loading system, our device is capable to apply static loads from the bottom of the samples to conduct monotonic triaxial tests as well. All of these systems are connected to a especial software and the user can control each step of the test by a computer as well as defining preferred user-defined testing procedures.
Special attachments:
This device can be further equipped with extra elements to conduct special testing procedures. These include bender elements to measure small-strain properties of the sample, local displacement transducers (longitudinal or circumferential) to precisely measure sample strain, special thermal triaxial cells to conduct temperature controlled tests and dynamic unsaturated testing units.
Technical specifications:
Static axial payload: Up to 1000 kN
Dynamic axial payload: Up to 1000 kN
Cyclic frequency: Up to 100 Hz
Confining pressure: Up to 1000 kPa (or higher on request)
Sample size: Up to 500 mm
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Multi-Directional Dynamic Simple Shear Apparatus
This device is capable to reproduce the stress conditions in a soil element during earthquake more accurately than a triaxial device. It can be used to obtain dynamic properties of soils as well as their liquefaction behavior. This device uses a series of stacked rings to restrict the lateral deflection of the sample during the test while applying two controlled cyclic horizontal shear stresses as well as a vertical stress on it. Conventional simple shear machines can simulate only K0-conditions while our sophisticated device is capable to impose initial stresses other than K0 conditions (e.g. anisotropic consolidation) utilizing special porous rings. Our simple shear apparatus employs 3-dimensional submersible load cells for simultaneous measurement of the stresses and its can control the dynamic loads independently in three directions.
Special attachments:
This device can be further equipped with extra elements to conduct special testing procedures. These include bender elements to measure small-strain properties of the sample, small non-contact sensors to measure strain in the sample during cyclic and dynamic testing procedures, special porous stacked rings to perform tests other than the KO-conditions.
Technical specifications:
Three dynamic servo-hydraulic actuators (one in vertical and two in horizontal directions)
Dynamic payload: Up to 25 kN
Cyclic frequency: Up to 20 Hz
Small and Large sample sizes: Up to 200 mm for large grain sizes
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Large Size Dynamic Hollow Cylinder Apparatus
This high quality and advanced testing machine is suitable for static and dynamic, axial and torsional, uniaxial and triaxial hollow torsional shear tests overcoming many of the problems associated with cyclic triaxial and simple shear tests. The test is conducted on hollow cylindrical samples to obtain stiffness and damping ratio of soils over a wide strain range of interest as well as liquefaction behavior of them. The powerful controlling system of this device can control different component of stress on the soil sample independently including external and internal pressures, axial stress and the cyclic torque (shear stress). Our hollow cylinder machine uses a closed loop control system proving an opportunity to perform both stress and strain-controlled tests. A fast data acquisition system is attached to this device which can record different types of data during the test while its powerful controlling software enables the user to define any complex testing procedure.
Special attachments:
This device can be further furnished with extra elements to conduct special testing procedures. These include small non-contact sensors to precisely measure strains in the sample during cyclic and dynamic testing procedures, special local displacement transducers (axial or circumferential) to record the specimen deformations internally in small-strain ranges.
Technical specifications:
Type of loading frame: Electromechanical / servo hydraulic
Axial load: Up to 150 kN
Loading frequency: Up to 100 Hz
Sample size: Up to 400/300/150 (height/outer diam./inner diam.)
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Resonant Column Apparatus
This device is most commonly used to obtain small-strain properties of geomaterials. Our especial device is a free-free type that can excite solid or hollow cylindrical specimens at their top in a torsional mode using a high-tech electromagnetic loading system. The loading system applies torsional harmonic load on the sample controlling its frequency and magnitude. The measure response of soil sample can be further used to obtain small-strain shear modulus and damping ratio of the soil adopting well-known logarithmic decrement or half-power methods. Also, the test can be performed under isotropic or anisotropic consolidation conditions.
Technical specifications:
Diameter of solid or hollow cylindrical samples: 38/50/70/100 or 150 mm
Cell pressure: Up to 1000 kPa (or higher on request)
Torsional loading frequency: Up to 2 kHz
Applied pore pressure: Up to 1000 kPa
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Resonance Column Monitoring Software
Cyclic Triaxial Apparatus
The soil dynamics laboratory is furnished with 4 cyclic triaxial apparatuses capable to follow any desired stress paths. These machines allow for accurate testing of liquefaction behavior of soils. All these devices have been designed and manufactured and installed through an in-house procedure in the laboratory. The controlling system of the devices uses an advanced closed loop algorithm allowing the user to define any cyclic loading scheme including compression or extension modes. The system is also capable to apply irregular loading waveform such as the stress history of earthquakes. Our cyclic triaxial devices can be further equipped with small-strain measuring units such as bender elements or non-contact proximity sensors to obtain dynamic properties of the soil samples at low strain levels.
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Small Strain Measurement Units (Bender elements)
Bender elements are electro-mechanical transducers which are capable of converting mechanical waves to electrical ones and vice versa. The soil dynamics laboratory maintains several sets of S-wave and P-wave bender elements made of piezoelectric ceramics (transmitter and receiver) which can be used with element testing machines or can be independently included in physical models to measure S or P-wave velocity of the soils. Bender elements are included in specific pedestals which can be added to element testing devices including dynamic and cyclic triaxial, dynamic simple shear or consolidation cells. This test can be performed specifically on triaxial cylindrical specimens with diameters from 35 to 300 mm or any customized sizes. The bender elements are powered by a wave signal generator and the feedback from the receiving element is converted to a digital signal, shown graphically on virtual oscilloscope software and finally stored in the computer to be subsequently used for shear wave velocity estimation.
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Triaxial Cells
Our soil dynamic laboratory maintain a number of extra triaxial cells attached to a pressure control panel which can be used to consolidate soil samples whose consolidation process is time consuming.
Central CO2 and Air Pressure Supply and Air Dryer Unit
The soil mechanics laboratory has central CO2 and air pressure systems which can be accessed in various locations inside the laboratory. The air pressure is mainly used to supply pneumatic actuators, applying cell pressure, supply vacuum producers and other devices. This lab is also equipped with a central air dryer system.
Central Cooling System and Air Compressor
The central cooling system of the soil dynamics laboratory cools the entire hydraulic system of element testing devices through a closed loop pipeline.
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