MT/T 593.5-2011Artificial frozen soil physics mechanics performance test. Part 5: Artificial frozen soil tri-axial shear test method (English PDF)

1 Scope

This Part of MT/T 593 specifies the instruments and equipment, specimens, basic requirements, test procedures, as well as calculations and plotting methods for multi- specimen and single-specimen triaxial compression tests on artificially frozen soil.

This Part is applicable to the testing and calculation of triaxial compressive strength parameters for frozen undisturbed soil and frozen remolded soil.

2 Normative references

The following documents are essential to the application of this document. For the dated documents, only the versions with the dates indicated are applicable to this document;

for the undated documents, only the latest version (including all the amendments) is applicable to this standard.

MT/T 593.1 Artificial frozen soil physics mechanics performance test - Part 1.

Artificial frozen soil experiment sample and specimen preparation method

MT/T 593.3 Artificial frozen soil physics mechanics performance test - Part 3.

Consolidation under hydrostatic pressure for artificial frozen soil test method

MT/T 593.4 Artificial frozen soil physics mechanics performance test - Part 4.

Artificial frozen soil uniaxial compression strength test method

3 Terms and definitions

The following terms and definitions apply to this document.

3.1

Tri-axial shear test

A process involving the application of axial compressive stress (principal stress difference sigma1 - sigma3) under various constant confining pressures (i.e., minor principal stress sigma2 = sigma3), subjecting the specimen to shear until failure occurs.

4 Instruments and equipment for testing

4.1 Triaxial compression tester (as shown in Figure 1). Features adjustable strain rates;

maximum axial load of 200 kN; confining pressure of 6 MPa (suitable for soil burial depths < 300 m), 12 MPa (suitable for soil burial depths < 700 m), or 20 MPa (suitable for soil burial depths < 1200 m), with a fluctuation tolerance not exceeding 10 kPa.

4.2 Stress and deformation test components. Pressure transducer (range. 0 kN ~ 200 kN;

accuracy. 1%); displacement transducer (axial range. 0 mm ~ 50 mm; accuracy. 1%);

automatic data acquisition system, etc.

4.3 Temperature sensor. Range. -40 °C ~ +40 °C; accuracy. 0.2 °C.

4.4 Cooling and temperature control equipment.

4.5 Equipment for testing moisture content and density of test specimens.

Figure 1 -- Low-temperature triaxial compression tester

5 Test specimens

5.1 Frozen undisturbed soil specimens and frozen remolded soil specimens shall be used; their preparation methods shall be carried out in accordance with the provisions of Clauses 6.2.2 and 6.2.3 in MT/T 593.1.

5.2 Test specifications shall be consistent with the specimen specification which is used in MT/T 593.4.

5.3 Number of specimens. 1 (for single-specimen staged loading) or 3 ~ 4 (for multi- specimen loading).

6 Basic requirements

6.1 The test shall be conducted at the specified test temperature.

6.2 The temperature fluctuation shall be less than or equal to ±0.2 °C.

6.3 If only one test temperature is required, -10 °C shall be selected; if multiple test temperatures are required, -10 °C shall be included among them; if there are special requirements, other test temperatures may be selected.

6.4 Prior to the test, all instruments and equipment used for the test shall be properly calibrated.

7 Test procedures

8 Calculations and plotting