Triaxial Apparatus

Triaxial Apparatus

1. Description

This equipment is aFully Automatic Triaxial Apparatus (BTU-TTS series), covering models TTS-1, 3, 6, 10, and 20. It is mainly used for triaxial compression tests in geotechnical testing, supporting standard test types such as Unconsolidated Undrained (UU), Consolidated Undrained (CU), and Consolidated Drained (CD). The system is equipped with high-precision volume controllers (cell/back pressure) and offers optional professional test modules (e.g., k0 consolidation, stress path, coefficient of subgrade reaction, elastic modulus, etc.), enabling fully automatic control and data acquisition.

2. Test Standards

• ASTM D7181(Consolidated Drained Triaxial Compression Test)
• ASTM D4767(Consolidated Undrained Triaxial Compression Test)
• ASTM D2850(Unconsolidated Undrained Triaxial Compression Test)
• BS 1377(British Standards for soil testing)
• SL 237-1999(Chinese specification for soil testing)

Optional modules (e.g., k0, elastic modulus) can support correspondingASTMorJGSstandards.

3. Specification (Parameter )

4. Detail (technical details)

• Tensile function: TTS-10 explicitly states "Max. tensile force 100 kN", indicating this model supports bidirectional loading (compression & tension), suitable for tensile or cyclic loading tests.
• Wide shearing speed range: TTS-3 and TTS-6 offer a maximum shearing speed of 20 mm/min for rapid strength tests, while a minimum of 0.00001 mm/min suits creep/rheology studies.
• Volume controllers: Independent cell and back pressure controllers, pressure 2–3 MPa, volume 60–100 ml, suitable for saturation and pressurization of small to medium specimens.
• Rich software modules: Besides standard UU, CU, CD, optional modules include k0 consolidation, stress path, coefficient of lateral earth pressure at rest, coefficient of subgrade reaction, shear modulus, elastic modulus (Duncan-Chang model), etc.

5. Application

• Teaching and research laboratories: routine geotechnical triaxial testing instruction
• Foundation and subgrade engineering: determination of shear strength parameters (c, φ)
• Excavation and slope stability analysis: strength parameters under different drainage conditions
• Soft soil and special soil studies: optional modules for coefficient of lateral earth pressure at rest, coefficient of subgrade reaction, modulus characteristics
• Geotechnical constitutive model parameter calibration: e.g., Duncan-Chang model E and B values

6. Advantages

• Fully automatic operation: from saturation, consolidation to shearing – fully automated control and recording
• Tensile function (TTS-10): supports tensile tests, expanding application range
• High maximum shearing speed (20 mm/min): suitable for rapid tests or stress-controlled loading
• Rich optional modules: one device can be extended for various advanced tests without purchasing separate equipment
• Cost-effective: covers core requirements of routine triaxial testing, suitable for batch configuration in teaching or production testing laboratories

7. What To Choose (selection guide)

8. Process Flow

Based on standard triaxial test procedures and the functions of this equipment, a typical test workflow is as follows:

• Specimen preparation→ prepare soil sample according to dimensions (e.g., Ø70×140 mm)
• Mounting & saturation→ mount specimen, connect cell/back pressure controllers, perform back pressure saturation and B-check
• Consolidation (optional)→ isotropic consolidation or k0 consolidation (if module equipped)
• Shearing stage(select according to test type):
  • UU: unconsolidated undrained shearing
  • CU: consolidated undrained with pore pressure measurement
  • CD: consolidated drained with volume change measurement
  • Stress path(optional module)
  • Elastic/shear modulus testing(optional)
• Data acquisition→ automatically record axial force, displacement, pore pressure, volume change, cell pressure, back pressure
• Post-processing→ software generates Mohr circles, stress-strain curves, strength parameters (c, φ)
• Optional module additional procedures→ e.g., coefficient of subgrade reaction test, coefficient of lateral earth pressure at rest test, performed according to corresponding specifications

Triaxial Apparatus Images