CN-115575510-A - Rock mass instability early warning method based on acoustic signal

CN115575510ACN 115575510 ACN115575510 ACN 115575510ACN-115575510-A

Abstract

The invention relates to a rock mass instability early warning method based on acoustic emission signals, which comprises the following steps of S1, adopting acoustic emission monitoring equipment to monitor the acoustic emission waveform of a rock mass in real time, and acquiring and recording an acoustic emission rise time parameter, wherein the acoustic emission rise time parameter is a time parameter of a rise stage of the acoustic emission waveform; s2, selecting n data from the acoustic emission rise time parameter, wherein n is more than or equal to 2; calculating the coefficient of variation Cv of the acoustic emission rise time under the set window length of the coefficient of variation, calculating the skewness Sk of the acoustic emission rise time under the set window length of skewness, and calculating the kurtosis Ku of the acoustic emission rise time under the set window length of kurtosis; and S3, judging whether the rock mass enters a destabilization state. The method has the advantages that the precursor points of the rock mass instability damage are easy to identify, simple to calculate and convenient to operate; the method can represent the state of the rock mass in real time, and can be widely used in rock mass early warning and forecasting in the fields of tunnel engineering, slope engineering, mining engineering, water conservancy and hydropower engineering and the like.

Inventors

ZHU XING
XU QIANG
WANG YOULIN
ZHU QINGSONG
LI SHUWU
YANG XIAN
ZHAO ZHIXIANG
BAO JIAN

Assignees

UNIV CHENGDU TECHNOLOGY
POWERCHINA NORTHWEST ENG CORP LTD

Dates

Publication Date: 20230106
Application Date: 20220928
Priority Date: 20220928

Claims (6)

1. A rock mass instability early warning method based on acoustic emission signals is characterized by comprising S1, monitoring an acoustic emission waveform of a rock mass in real time by adopting an acoustic emission monitoring device, and acquiring and recording an acoustic emission rise time parameter, wherein the acoustic emission rise time parameter is a time parameter of a rise stage of the acoustic emission waveform; s2, selecting n data from the acoustic emission rise time parameter, wherein n is more than or equal to 2; calculating the coefficient of variation Cv of the rising time of the acoustic emission under the set length of the coefficient of variation window, wherein the calculation formula is as follows: wherein n represents the data amount, n is not less than 2 i Which represents the (i) th data, represents the average of n data; under the set skewness window length, calculating the skewness Sk of the acoustic emission rise time, wherein the calculation formula is as follows: under the set length of the kurtosis window, calculating the kurtosis Ku of the acoustic emission rise time, wherein the calculation formula is as follows: s3, judging whether the rock mass is about to enter a destabilization state by adopting one of the following two ways: the first method comprises the following steps: setting the threshold values of the coefficient of variation, the skewness and the kurtosis, and respectively comparing the coefficient of variation Cv, the skewness Sk, the kurtosis with the corresponding threshold values; if the comparison result meets the alarm condition, alarming; if the comparison result does not meet the alarm condition, repeating the steps from S1 to S3; the alarm condition comprises one of the following conditions: 1. the coefficient of variation Cv, skewness Sk and kurtosis Ku are all larger than corresponding thresholds; 2. the coefficient of variation Cv is greater than a corresponding threshold, and one of the skewness Sk and the kurtosis Ku is greater than a corresponding threshold; 3. one of the coefficient of variation Cv, skewness Sk and kurtosis is greater than a corresponding threshold; and the second method comprises the following steps: and (3) taking time as an abscissa, respectively taking the acoustic emission rise time variation coefficient, the skewness and the kurtosis as an ordinate, drawing a variation graph of the variation coefficient along with time, a variation graph of the skewness along with time and a variation graph of the kurtosis along with time, and alarming when the variation coefficient, the skewness and the kurtosis are rapidly increased.
2. The rock mass instability early warning method based on the acoustic signal as claimed in claim 1, characterized in that: the length of the coefficient of variation window is 100-1000.
3. The rock mass instability early warning method based on the acoustic emission signal as claimed in claim 1, characterized in that: the length of the skewness window and the kurtosis window is greater than 5000.
4. The rock mass instability early warning method based on the acoustic signal as claimed in claim 2, characterized in that: the threshold value of the coefficient of variation is 3-8, and the threshold value of the coefficient of variation is inversely related to the length of the window of the coefficient of variation.
5. A rock mass instability early warning method based on acoustic signals as claimed in claim 3, characterized in that: the threshold value of the skewness is 7-14, and the threshold value of the skewness is positively correlated with the length of a skewness window.
6. A rock mass instability early warning method based on acoustic emission signals as claimed in claim 3, characterized in that: the threshold value of the kurtosis is 100-600, and the threshold value of the kurtosis is positively correlated with the length of a kurtosis window.

Description

Rock mass instability early warning method based on acoustic signal Technical Field The invention belongs to the technical field of rock mass instability early warning, and particularly relates to a rock mass instability early warning method based on acoustic signals. Background With the excavation of slope engineering, the engineering construction of tunnels, mining, underground spaces and the like is continuously promoted to the deep part, and a series of geological disasters such as collapse, large deformation, rock burst, landslide and the like can be induced. Therefore, the method and the device can accurately forecast and early warn the instability and damage of the rock mass in real time, and have important significance for avoiding the loss of life and property. The unstable process that destroys of rock mass often can be accompanied with the production of deflection, but the rock mass is as brittle material, and its deformation is less relatively, and possesses stronger proruption nature, consequently regards displacement volume as early warning index reliability very poor, is difficult to early warning in time. Acoustic emission refers to transient elastic waves generated by rapid release of local strain energy inside or on the surface of a material, and represents changes of real-time states of rock masses, and currently, researchers take acoustic emission wave velocity, frequency, b value, fractal dimension, RA/AF, kaiser point and the like as precursor indexes, such as an acoustic emission multi-precursor method and device for warning instability of CN202010821211.7 pull-shear dumping type karst rock, a hard rock joint surface sudden destabilization warning method monitored by cn202011091. X, a coal rock instability damage precursor information identification method of CN202111665539.5, a rock instability damage stage prediction method, a device, a system and a storage medium of CN201910638985.3, a rock instability stage prediction method and device of CN201910638983.4 based on multi-feature fusion, and a rock mode intelligent detection identification method based on CN202010144388.8 model, and the like. Disclosure of Invention The invention aims to solve the technical problem of providing a rock mass instability early warning method based on acoustic signals, which has the advantages of easy identification of precursor points, simple calculation and judgment, low implementation difficulty, real-time tracking, early warning and forecasting of rock mass states and direct application to engineering construction. In order to solve the problems, the technical scheme adopted by the invention is as follows: a rock mass instability early warning method based on acoustic emission signals comprises S1, monitoring an acoustic emission waveform of a rock mass in real time by adopting an acoustic emission monitoring device, and acquiring and recording an acoustic emission rise time parameter, wherein the acoustic emission rise time parameter is a time parameter of a rise stage of the acoustic emission waveform; s2, selecting n data from the acoustic emission rising time parameter, wherein n is more than or equal to 2; calculating the coefficient of variation Cv of the rising time of the acoustic emission under the set length of the coefficient of variation window, wherein the calculation formula is as follows: wherein n represents the data amount, n is not less than 2 i Which represents the (i) th data,represents the average of n data; under the set skewness window length, calculating the skewness Sk of the rising time of the acoustic emission, wherein the calculation formula is as follows: under the set length of the kurtosis window, calculating the kurtosis Ku of the acoustic emission rise time, wherein the calculation formula is as follows: s3, judging whether the rock mass is about to enter a destabilization state by adopting one of the following two modes: the first method comprises the following steps: setting the threshold values of the coefficient of variation, the skewness and the kurtosis, and respectively comparing the coefficient of variation Cv, the skewness Sk, the kurtosis with the corresponding threshold values; if the comparison result meets the alarm condition, alarming; if the comparison result does not meet the alarm condition, repeating the steps S1 to S3; the alarm condition comprises one of the following conditions: 1. the coefficient of variation Cv, the skewness Sk and the kurtosis are all larger than corresponding thresholds; 2. the coefficient of variation Cv is greater than a corresponding threshold, and one of the skewness Sk and the kurtosis Ku is greater than a corresponding threshold; 3. one of the coefficient of variation Cv, the skewness Sk and the kurtosis is larger than a corresponding threshold; and the second method comprises the following steps: and (3) taking time as an abscissa, respectively taking the acoustic emission rise time variation coefficient, the skewness