MT 45-1987 in English
VALIDDetermination Methods for Deformation Parameters of Coal and Rock
- Issued on:1987-11-18
- Implemented on:1987-12-10
- File Format:PDF
- Delivery:Via email within 1~3 business days
Price(USD)：
$90.00
$88.00
$88.00
本标准适用于能够加工成标准试件的岩石和煤的变形参数「包括变形模量的割线模量E,o、切线模量F.,(通称弹性模量)及泊松比产〕的测定。
Introduction
Analysis of the core content of the standard
This standard replaces the MT 45-80 version and specifies the complete process of using resistance strain gauges to measure the deformation parameters of coal and rock masses, with the focus on:
- Deformation modulus (secant modulus E50 and tangent modulus Et)
- Accurate determination method of Poisson's ratio μ
- Requirements for specimen processing accuracy control (in accordance with Chapter 2 of MT 44-87)
Comparison of key technologies
| Parameter type | Determination method | Calculation formula | Accuracy requirements |
|---|---|---|---|
| Secant modulus E50 | Slope of the 50% strength point of the stress-strain curve | E50=σ50/ε50 | Accurate to the thousandth place (MPa) |
| Tangent modulus Et | Slope of the linear segment | Et=(σb-σa)/(εb-εa) | Accurate to the thousandth place (MPa) |
| Poisson's ratio μ | Transverse/longitudinal strain ratio | μ=|εhorizontal/εvertical| | Keep two decimal places |
Detailed explanation of key points
Specifications for pasting resistor sheets
The standard requires the use of resistor sheets with specifications of 3×15-3×20mm. Key control points:
- The length of the resistor wire needs to be ＞10 times the maximum rock particle size
- The resistance difference between the working sheet and the compensation sheet is ≤0.5Ω
- Adopt a "W-shaped" patch layout (3 pieces vertically/horizontally)
Moisture-proof treatment process
For specimens with different water content:
- Dry specimen: 502 glue + epoxy resin coating (thickness ≤ 0.1mm)
- Saturated specimen: special moisture-proof glue + double-layer sealing treatment
- Final insulation resistance＞200MΩ
Standard evolution analysis
Main improvements compared to the 1980 version:
- Added high resistance meter testing requirements
- Refined the use specifications of moisture-proof glue
- Clarified the volume strain calculation formula (εv=ε1-2εd)
- Added the application instructions of automatic recording device
Implementation suggestions
- Equipment selection: Prioritize the use of 0.5 level accuracy material testing machine
- Data verification: The number of parallel specimens is ≥ 3, and the discreteness is greater than 15%, so re-test is required
- Abnormal handling: When the strain value difference is greater than 10%, the spherical seat should be adjusted
- Result report: The coordinates of the characteristic points of the stress-strain curve must be included
Sample only — not a preview of MT 45-1987
Loading PDF document...
Error loading PDF. Please make sure the file is valid and try again.
We also recommend
-
MT/T 1053-2007 in English
Technical Conditions of Microscope Photometer for Vitrinite Reflectance Determination
2008-11-19 -
MT/T 621-2006 in English
Sampling for checking samples of production in coalmine
2006-05-12 -
MT/T 967-2005 in English
Classification for germanium in coal
2005-09-23
