GB/T 50266-1999 in English

1.0.1 This standard is formulated to unify the engineering rock mass test methods, improve the test results and strengthen the comparability of test results.
1.0.2 This standard is applicable to the rock test of the projects such as water conservancy, hydropower, mining area, railway, trafficking, petroleum, national defense as well as industrial and civil buildings.
1.0.3 Rock test objects shall be equipped with geologic representativeness. Rock test content, test methods and technical conditions shall meet the basic requirements and conform to the characteristics of the engineering construction exploration survey, design and construction.
1.0.4 Except that the rock test conforms to this standard, it shall also meet the requirements of the current relevant standards.

1 General Provisions 1
2 Rock Masses Test 1
2.1 Water Content Test 1
2.2 Grain Density Test 2
2.3 Block Density Test 3
2.4 Water Absorption Test 6
2.5 Expansion Test 7
2.6 Slaking Durability Test 10
2.7 Uniaxial Compressive Strength Test 12
2.8 Uniaxial Compression and Deformation Test 13
2.9 Triaxial Compression Strength Test 15
2.10 Tensile Strength Test 16
2.11 Direct Shear Test 16
2.12 Point Load Strength Test 19
3 Rock Deformation Test 21
3.1 Test of Bearing Plate Method 21
3.2 Drill Hole Deformation Test 27
4 Rock Strength Test 29
4.1 Direct Shear Test of Rock Mass Structure Plane 29
4.2 Direct Shear Test of Rock Masses 33
5 Stress Test of Rock Masses 34
5.1 Hole Wall Strain Test 34
5.2 Test with Aperture Distortion Method 36
5.3 Test with Bottom Hole Strain 37
6 Observation at the Original Position of Rock Masses 39
6.1 Enclosing Rock Convergence Observation of Underground Cavity 39
6.2 Displacement Observation of Drilling Axial Rock Masses 40
6.3 Displacement Observation of Drilling Crosswise Rock Masses 41
7 Sonoprobe Method of Rock 43
7.1 Acoustic Speed Test of Rock 43
7.2 Acoustic Speed Test of Rock 44
Appendix A Rock Stress Calculation 47
Appendix B Explanation of Wording in this Standard 53
Additional Explanations 54