A multi-scale entropy characterization method for internal defect distribution of anchorage system

Abstract

The invention discloses a multi-scale entropy characterization method of inner defect distribution of an anchoring system. The multi-scale entropy characterization method comprises the following steps: detecting an anchor rod needing to be detected in a working site by utilizing an anchor rod anchoring quality non-destructive testing instrument based on a stress wave method and identifying an anchor rod anchoring length; carrying out empirical mode decomposition on a non-destructive testing signal and decomposing the non-destructive testing signal into a series of intrinsic mode functions which are arrayed according to levels of the frequency of the signal; calculating the frequency of each layer of intrinsic mode function through utilizing Fourier transformation; abandoning the intrinsic mode function with the frequency more than 1kHz and the final layer of intrinsic mode function; overlapping all layers of the intrinsic mode functions with the frequency smaller than 1kHz; and reconstructing a new signal for multi-scale entropy analysis. The change degree of a reflection signal is described through measuring the complexity of a reflected signal, so that the positions of anchoring defects are identified; and the method can be used for effectively judging the positions of the anchoring defects and accurately evaluating the anchoring quality.

Description

technical field [0001] The invention relates to the technical field of anchoring systems, in particular to a multi-scale entropy characterization method for internal defect distribution of an anchoring system. Background technique [0002] Existing studies have shown that the stress distribution along the length of the bolt is not uniform. The difference in the distribution of anchoring defects will lead to differences in the stress state of the anchor rod. In the actual detection of underground coal mines, even if the pull-out resistance is confirmed to meet the requirements through the pull-out test, there will still be collapse accidents due to insufficient mortar pouring, which will affect the safe production of coal mines. The existing technology has poor ability to effectively identify the location of the anchoring defect, and cannot accurately locate the location of the anchoring defect, which in turn has a negative impact on the evaluation of the anchoring quality o...

AI Technical Summary

Problems solved by technology

[0002] Existing studies have shown that the stress distribution along the length of the anchor is not uniform

The different distribution positions of the anchoring defects will lead to differences in the stress state of the anchor rod.

In the actual detection of underground coal mines, even if the pull-out resistance is confirmed to meet the requirements through the pull-out test, there will still be collapse accidents due to insufficient mortar filling, which will affect the safe production of coal mines

The existing technology has poor ability to effectively identify the location of the anchoring defect, and cannot accurately locate the location of the anchoring defect, which in turn has a negative impact on the evaluation of the anchorage quality of the bolt, leading to safety accidents

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