DZ/T 0276.22-2015Regulation for testing the physical and mechanical properties of rock. Part 22: Test for determining the flexural strength of rock (English PDF)

Foreword

DZ/T 0276 "Testing Procedures for Physical and Mechanical Properties of Rocks" is divided into 31 parts.

--- Part 1. General and general provisions;

--- Part 2. Rock moisture test;

--- Part 3. Rock particle density test;

--- Part 4. Rock density test;

---Part 5. Rock water absorption test;

---Part 6. Rock hardness test;

--- Part 7. Rock gloss test;

--- Part 8. Rock antifreeze test;

---Part 9. Rock resistance to disintegration test;

--- Part 10. Rock expansion test;

--- Part 11. Rock erosion test;

--- Part 12. Rock acid and alkali resistance test;

--- Part 13. Rock specific heat test;

--- Part 14. Rock thermal conductivity test;

---Part 15. Rock breakdown voltage and breakdown strength test;

---Part 16. Rock volume resistivity and surface resistivity test;

--- Part 17. Rock radioactivity specific activity test;

---Part 18. Rock uniaxial compressive strength test;

---Part 19. Rock uniaxial compression deformation test;

--- Part 20. Rock triaxial compression strength test;

--- Part 21. Rock tensile strength test;

--- Part 22. Rock flexural strength test;

--- Part 23. Rock point load strength test;

--- Part 24. Rock acoustic wave velocity test;

---Part 25. Rock shear strength test;

--- Part 26. Rock mass deformation test (bearing plate method);

--- Part 27. Rock mass deformation test (drilling deformation method);

---Part 28. Rock mass strength test (direct shear test);

--- Part 29. Rock mass strength test (bearing plate method);

--- Part 30. Rock mass bolt load test;

--- Part 31. Rock sound wave velocity test.

This part is part 22 of DZ/T 0276.

This part is drafted in accordance with the rules given in GB/T 1.1-2009.

This part replaces DY-94 "Testing procedures for physical and mechanical properties of rocks. 19. Tensile strength test (cracking method)". This part and DY-94 in comparison, the main technical changes are as follows.

--- Added two chapters of "terms and definitions" and "principles";

---Modified the press in the equipment and changed to the material testing machine;

---Modified the accuracy requirements of the test results;

--- Revised the rock flexural strength test record table.

This part is proposed by the Ministry of Land and Resources of the People's Republic of China.

This part is under the jurisdiction of the National Land Resources Standardization Technical Committee (SAC/TC93).

This section drafted by. Hubei Institute of Geological Experiments.

Drafters of this section. Liu Lizhi, Liu Bing, Chen Yu.

The previous versions of the standards replaced by this section are.

---DY-86;

---DY-94.

Rock physics and mechanics properties test procedures Part 22. Rock flexural strength test

1 Scope

This part of DZ/T 0276 specifies the test method for determining the flexural strength of rock.

This section applies to the tensile strength test of rock in the physical and mechanical properties of rock.

2 Terms and definitions

The following terms and definitions apply to this document.

Flexural strength the maximum stress that a rock specimen can withstand when bent to break.

3 Principle

The rock is processed into a strip test piece, placed on two fixed fulcrums, and a concentrated load is applied at the midpoint of the sample until the test piece is destroyed.

The theory of sexual mechanics calculates the flexural strength of rock.

4 Instruments

4.1 Material testing machine. The indication error is not more than ±1%.

4.2 Simple beam bending device, see Figure 1.

4.3 Diamond machine, stone cutting machine, stone grinding machine.

4.4 Vernier caliper. The range is 15cm and the accuracy is 0.02mm.

Description.

l---sample span;

h---sample height;

p---concentrated load;

r---the radius of curvature of the fulcrum;

1---sample;

2---lower fulcrum;

3---Upper fulcrum.

Figure 1 Schematic diagram of the bending device