Rock elastic-creep modulus and determination method thereof

A technique for determining the method and modulus, which is applied in the field of rock elastic-creep modulus and its determination, can solve problems such as error, failure to consider rock creep characteristics, and inapplicability, and achieve the effect of small error and simplified quantitative analysis and research work

Inactive Publication Date: 2020-01-17
ANHUI UNIV OF SCI & TECH
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Problems solved by technology

[0002] The elastic modulus of rock has always been an important parameter basis for the design of coal mine roadway support. The secant elastic modulus of the peak point of the full stress-strain curve. Obviously, the elastic modulus obtained by this method does not consider the creep characteristics of the rock in the surrounding rock of the actual coal mine roadway, so that the calculation results of the specific support parameters of the roadway There is a large error with the actual situation, which is also one of the important reasons why coal mine soft rock roadway partial side, roof fall, section greatly reduced, serious bottom drum and other phenomena still commonly exist in my country's coal mining
It can be seen that the elastic modulus used in the past is actually not suitable for the surrounding rock of the roadway where creep occurs.

Method used

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  • Rock elastic-creep modulus and determination method thereof
  • Rock elastic-creep modulus and determination method thereof
  • Rock elastic-creep modulus and determination method thereof

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Embodiment 1

[0022] Such as figure 2 Shown, embodiment 1 of the present invention provides a kind of determination method of rock elastic creep modulus, comprises following steps:

[0023] 1) Select a group of rock specimens, and set the uniaxial compression test and stable creep test when the confining pressure is 11MPa respectively for the selected rock specimens, and determine the following figure 2 The shown total stress-strain curve 8 of the rock specimen under the confining pressure of 11MPa, and the upper threshold point 9 of the stable creep under the confining pressure, the stress value corresponding to the upper threshold point of the stable creep is 50MPa, and the ring The vertical strain value is 0.024.

[0024] 2) Since the calculation formula of elastic-creep modulus can be expressed as: E ec =(σ 1 ) ec / (ε 1 ) ec , and where (σ 1 ) ec is the lower threshold of stable creep of surrounding rock, (ε 1 ) ec is the hoop strain value corresponding to the lower threshol...

Embodiment 2

[0026] Such as image 3 Shown, embodiment 2 of the present invention provides a kind of determination method of rock elastic creep modulus, comprises following steps:

[0027] 1) Select a group of rock specimens, set the uniaxial compression test and stable creep test when the confining pressure is 19MPa respectively for the selected rock specimens, determine the following figure 2 The shown total stress-strain curve 10 of the rock specimen under a confining pressure of 19MPa, and the upper threshold point 11 of stable creep under this confining pressure, the stress value corresponding to the upper threshold point of stable creep is 64MPa, and the ring The vertical strain value is 0.03.

[0028] 2) Since the calculation formula of elastic-creep modulus can be expressed as: E ec =(σ 1 ) ec / (ε 1 ) ec, and where (σ 1 ) ec is the upper threshold of stable creep of surrounding rock, (ε 1 ) ec is the hoop strain value corresponding to the upper threshold of stable creep ...

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Abstract

The invention provides a rock elastic-creep modulus and a determination method thereof. The elastic-creep modulus is the slope of a replacement straight line segment 5 of an elastic stage 1 and a plastic hardening stage 2 in a surrounding rock four-stage strain softening model based on creep prerequisites; a large number of experiments show that for a specific rock, in a surrounding rock four-stage strain softening model based on the creep precondition, the slopes of the elastic stage 1 and the plastic hardening stage 2 are very close, and therefore the two straight lines can be approximatelyreplaced with line segments 5; the stress state of the second stage before and after stable creep can be regarded as unchanged, and surrounding rock deformation before stable creep belongs to elasticdeformation under the condition of rapid loading, so that the stress state of the whole second stage can be calculated according to an elastic theory, and the elastic creep modulus can be used as an elastic modulus for calculation. According to the method, deformation analysis of roadway surrounding rock and quantitative research work of surrounding rock supporting in underground rock engineeringcan be greatly simplified, and errors are small.

Description

technical field [0001] The invention relates to the technical field of coal mine roadway support, in particular to a rock modulus of elasticity and a method for determining the same. Background technique [0002] The elastic modulus of rock has always been an important parameter basis for the design of coal mine roadway support. The secant elastic modulus of the peak point of the full stress-strain curve. Obviously, the elastic modulus obtained by this method does not consider the creep characteristics of the rock in the surrounding rock of the actual coal mine roadway, so that the calculation results of the specific support parameters of the roadway There is a large error with the actual situation, which is also one of the important reasons why soft rock roadways in coal mines are still common in my country's coal mining today, such as partial sidewalls, roof fall, greatly reduced cross-sections, and severe floor drums. It can be seen that the elastic modulus used in the pas...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): G06F30/20
Inventor 经纬王旭郭瑞
Owner ANHUI UNIV OF SCI & TECH
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