MT 173-1987 in English

Analysis of the core content of the standard

This standard defines the determination method of the rock disintegration resistance index, which quantitatively evaluates the rock sample's ability to resist softening and disintegration by simulating the dry-wet cycle effect through the disintegration resistance instrument. The test process includes 2 standard cycles, each cycle includes 24 hours of drying and 200 rotations of water immersion experiments.

Technical requirements of instruments and equipment

Specimen Preparation Specifications

Key points of the test process

1. Initial drying: 105℃ oven for 24h→cooling in dryer
2. First cycle: 200 rpm immersion→drying→weighing (mass A)
3. Second cycle: repeat the operation→weighing (mass B)
4. Final weighing: empty tube mass C

Calculation result verification

Disintegration resistance index formula: Id=(BC)/(AC)×100%. Example of sandstone test data: A=452.3g, B=418.7g, C=201.5g, then Id=(418.7-201.5)/(452.3-201.5)×100%=86.6%

Standard Technology Evolution

The 1987 version of the standard first established a quantitative test method for dry-wet cycles, which has three major innovations compared to the early qualitative observation method: 1) standardized rotation parameters; 2) accurate mass loss measurement; 3) dual-cycle enhanced discrimination. The current standard still maintains these core frameworks.

Implementation suggestions

• Laboratories need to control water temperature fluctuations ≤±2℃
• It is recommended to increase the record of specimen surface morphology
• For highly plastic clay rock, the drying time can be extended
• Regularly check the integrity of the screen of the test cylinder