Rock fracture early warning method based on acoustic emission signal statistical analysis

Abstract

The invention discloses a rock fracture early warning method based on acoustic emission signal statistical analysis, and belongs to the field of rock mechanics and geotechnical engineering. Firstly, real-time acoustic emission monitoring is carried out on the rock deformation and damage process, and ringing counts are recorded and obtained; secondly, the characteristic statistics, including variance and autocorrelation coefficient,of ringing counts is calculated through a formula, and the variance of ringing counts and the change rate of autocorrelation coefficient are calculated; and finally,early warning signal discrimination is carried out according to the variance of ringing counts and the change rate of the autocorrelation coefficient. When the change rate is greater than the threshold, the system automatically gives an alarm to indicate that the rock is about to crack. If the change rate does not exceed the threshold, monitoring and judging are continuous. According to the earlywarning method, early warning signal points are easy to identify and stable in calculation, and objectivity and accuracy of the early warning method can be ensured; the calculation process is simpleand convenient to operate; real-time tracking and early warning can be achieved, and the method can be widely applied to rock damage early warning in the engineering fields of water conservancy and hydropower, transportation, mineral resource exploitation, underground space development and the like.

Description

technical field [0001] The invention belongs to the field of rock mechanics and geotechnical engineering, and relates to a rock fracture early warning method based on statistical analysis of acoustic emission signals, which is suitable for rock fracture prediction and early warning encountered in civil engineering, water conservancy and hydropower engineering, mining engineering, and transportation engineering. Background technique [0002] With the continuous advancement of mining, tunnel excavation, construction of water conservancy projects, and development and utilization of underground space, the geological conditions of the rock masses involved in the construction and operation of the project are more complex, and the stability evaluation of the project is very important. Rock cracking will cause a series of geological disasters such as landslides, rockbursts, collapses, and large deformations of tunnels, seriously threatening the safety and service life of the project....

AI Technical Summary

Problems solved by technology

Because rock is a typical heterogeneous brittle material, the deformation is not significant before failure, so it is very difficult to use the deformation amount and its change rate for early warning

Acoustic emission signals increase during rock failure, which can be directly used as a precursor signal of rock failure through the significant increase in the number of acoustic emissions and the release rate, but there are also disadvantages that the early warning signal points are difficult to accurately identify

And it is easy to be interfered by some abnormal acoustic emission signals and lead to misjudgment. These acoustic emission signals reflect the local strain energy release process of rocks, but do not play a key role in the macroscopic damage of rocks.

In view of this, many scholars have also discussed the use of parameters such as b value, frequency spectrum, spatial correlation length, and fractal dimension for early warning of rock failure, but the changes in these parameters are not significant, and it is difficult to determine early warning signal points in actual operation

Due to the complexity of rock failure and the limitations of research methods, there is no very effective early warning technology or method for rock failure.

Images