Method for testing three-dimensional ground stress by aid of acoustic emission processes

Abstract

The invention discloses a three-dimensional in-situ stress testing method by acoustic emission method, comprising the following steps: 1) sampling and processing; 2) uniaxial acoustic emission test; 3) drawing a stress-accumulated acoustic emission ringing count-time curve; 4) Quickly discriminate the Kaiser effect points; 5) Calculate the three-dimensional stress state of the in-situ stress measuring points. The rock specimen sampling direction angle of the invention is flexible, the Kaiser effect point identification is quick and easy, the error in the calculation result of the in-situ stress caused by the deviation of the sampling angle is reduced, and the accuracy of the original rock stress test is also ensured.

Description

Technical field [0001] The invention relates to a method for testing ground stress, in particular to a method for three-dimensional ground stress testing using acoustic emission. Background technique [0002] When the material is subjected to an external load, the strain energy stored in the material is quickly released to produce elastic waves and sound, which is called acoustic emission. In 1959, EJKaiser found that after the stress of polycrystalline metal was released from its highest level in history, after reloading, when the stress did not reach the previous maximum stress, there was little acoustic emission, and when the stress reached the previous maximum stress or exceeded it, it would occur. A large amount of acoustic emission, this phenomenon is called the Kaiser effect, and the turning point from little acoustic emission to a large amount of acoustic emission is called the Kaiser point. Later, R.E. Goodman proved that the rock also has the Kaiser effect during the l...

AI Technical Summary

Problems solved by technology

[0009] However, due to the poor propagation of sound waves in plastic rock mass, which affects the acoustic emission Kaiser effect of plastic rock mass, this method cannot be applied to plastic rock mass.

Moreover, there are still some deficiencies in the precise identification method of Kaiser effect points and the calculation method of Kaiser effect ground stress, which affects the popularization and application of this method.

On the other hand, the existing acoustic emission methods usually have fixed requirements on the sampling direction, and it is difficult to meet the accuracy requirements during the operation, because the sampling direction will lead to errors in the test results

[0010] Therefore, those skilled in the art are committed to providing a convenient, quick, and easy-to-operate Kaiser effect point identification method for the problems of Kaiser effect point identification difficulties and fixed sampling angles that exist in the current acoustic emission method in-situ stress test process.

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