A Method for Determining Critical Strain of Rock Instability Considering Time Effect

A critical strain and determination method technology, applied in the field of geotechnical engineering, can solve problems such as large errors and inability to truly reflect rock instability characteristics, and achieve the effects of less strain series, objective calculation results, and high precision

Active Publication Date: 2019-10-08
NORTH CHINA UNIV OF WATER RESOURCES & ELECTRIC POWER
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

The determination method of the present invention can solve the problem that the evaluation method in the prior art cannot truly reflect the actual instability characteristics of the rock and has large errors; it can accurately obtain the critical strain of the rock instability

Method used

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  • A Method for Determining Critical Strain of Rock Instability Considering Time Effect
  • A Method for Determining Critical Strain of Rock Instability Considering Time Effect
  • A Method for Determining Critical Strain of Rock Instability Considering Time Effect

Examples

Experimental program
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Effect test

Embodiment 1

[0052] Taking the silty mudstone of a highway project in southwest my country as an example, based on laboratory experiments and numerical experiments, the critical strain of silty mudstone instability considering the time effect is determined. The specific operation steps are as follows:

[0053] a. Collect silty mudstone rock blocks on site, and use the water drilling method to drill core samples after transporting them to the laboratory. Use a stone sawing machine to cut the two ends of the core evenly, and grind them on a stone grinder to make a diameter of 50mm and a height of 100mm. The standard cylindrical sample; the deviation of the end surface of the sample is controlled within ±0.003mm, and the deviation of the perpendicularity of the end surface to the axis of the sample is controlled within ±0.25°;

[0054] b. Firstly, use a rock pressure testing machine to carry out a conventional triaxial test on the silty mudstone sample. According to the actual lateral stress o...

Embodiment 2

[0062] Taking carbonaceous slate in a water conservancy project in western my country as an example, based on laboratory experiments and numerical experiments, the critical strain of carbonaceous slate considering the time effect is determined. The specific operation steps are as follows:

[0063] a. Collect carbonaceous slate rock blocks on site, and use water drilling method to drill core samples after transporting them to the laboratory. Cut the two ends of the cores flat with a stone sawing machine, grind them on a stone grinder, and make them with a diameter of 50mm and a height of 100mm The standard cylindrical sample; the deviation of the end surface of the sample is controlled within ±0.003mm, and the deviation of the perpendicularity of the end surface to the axis of the sample is controlled within ±0.25°;

[0064] b. Firstly, the carbonaceous slate sample is subjected to a conventional triaxial test using a rock pressure testing machine. According to the actual latera...

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Abstract

The invention discloses a determination method for rock unstability critical strain considering time effect. The method comprises the following steps: firstly preparing a rock sample; performing a three-axis stress relaxation laboratory test to the rock sample by using a rheometer, to obtain a stress relaxation curve of the rock; determining a rock unstability critical strain range through the three-axis stress relaxation laboratory test; according to the obtained stress relaxation curve of the rock, building a stress relaxation model of the rock sample, to obtain model parameters; according to the size and feature of the prepared rock sample, building a numerical value model corresponding to the rock sample; and dividing the obtained rock unstability critical strain range to several partsas axial strain values to be applied in a numerical test, and performing the three-axis stress relaxation numerical test to the rock sample, to obtain an unstability critical strain exact value of the rock sample through the three-axis stress relaxation numerical test. The method is capable of solving the problems of the evaluation method in the prior art that the actual unstability features cannot be reflected faithfully and the error is large, and accurately getting the rock unstability critical strain.

Description

[0001] 1. Technical field: [0002] The invention relates to the field of geotechnical engineering, in particular to a method for determining critical strain of rock instability in consideration of time effect. [0003] 2. Background technology: [0004] The rock is deformed by external force, and the deformation of the rock continues to increase with the continuous action of the external force, which will eventually lead to sudden fracture and instability of the rock, causing geological disasters such as collapses, landslides, and rockbursts. As a key index for judging rock failure and instability, the study of rock instability critical strain has an important influence on the prediction and prevention of geological disasters. A large number of engineering practices have shown that the failure and instability of rock engineering do not occur immediately in many cases, and the process from the initial deformation to the final instability and failure of rock engineering is a com...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): G01N3/08G01N1/28
Inventor 于怀昌刘汉东姜彤张兴胜王洪建赵阳张俊然潘广钊席伟
Owner NORTH CHINA UNIV OF WATER RESOURCES & ELECTRIC POWER
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