CN104965027B - The analysis method extended based on image recognition and sound emission positioning and anchoring rock cranny - Google Patents

Abstract

The invention relates to an analysis method for locating the expansion of cracks in anchored rock mass based on image recognition and acoustic emission, which belongs to the method for analyzing the expansion of cracks in anchored rock mass. By loading different anchored samples, on the one hand, the acoustic emission sensor can receive the events and various signals generated inside the sample, and process the acoustic emission ringing count of the sample to obtain the "activity coefficient-time" curve, which reflects the The different activity periods in the loading process of the sample are analyzed, and the internal positioning is carried out through the occurrence of acoustic emission events, so as to characterize the internal damage and fracture of the sample; , the displacement and strain of the sample calculation area can intuitively judge the crack expansion process during the loading process of the sample. Revealing the acoustic emission characteristics and deformation characteristics of different anchoring samples under load can provide a theoretical basis and data prediction for coal mine bolt support, and also provide a good reference for related anchoring projects.

Description

An Analysis Method Based on Image Recognition and Acoustic Emission to Locate the Expansion of Cracks in Anchored Rock Mass

technical field

The invention relates to a method for analyzing the crack expansion of an anchored rock mass, in particular to an analysis method for locating the crack expansion of an anchored rock mass based on image recognition and acoustic emission.

Background technique

In many rock mechanics problems, the rock mass is not a continuous medium, that is to say, the surface and interior of the rock mass contain a large number of defects such as weak planes and cracks. In engineering, due to the disturbance of the external stress environment, especially in underground engineering During the excavation process of the middle roadway, a series of weakened structures have crack initiation, expansion, joint and even penetration, forming a discontinuous structure with interlaced space. A large number of practical projects have proved that roadway deformation, even instability and roof fall in underground engineering are closely related to these discontinuous weakened structures. In these cases, the method of anchoring and strengthening support is generally used. The physical and mechanical properties of cracks in rock mass show complex anisotropy, discontinuity and inhomogeneity, which brings great difficulties to support design and safety issues in rock engineering. , the strengthening degree and anchoring characteristics of rock mass have always been a hot and difficult point in the field of rock mechanics, but there are few systematic descriptions of the initiation, expansion, and combination of cracks before and after anchoring. Therefore, through acoustic and Image studies the acoustic emission characteristics and image deformation characteristics of the anchored sample during the loading process, and explores the relationship between the acoustic emission parameters and image recognition displacement, strain and damage mechanism of the sample, which can better provide complex cracks. The stability of anchoring works provides basic data and useful references for related engineering construction.

Contents of the invention

The purpose of the present invention is to provide an analysis method based on image recognition and acoustic emission to locate the crack expansion of anchored rock mass, to reveal the crack initiation, expansion, and joint evolution process of different anchorage samples under load, and to provide complex cracks for complex cracks. The stability of anchoring works provides basic data and useful references for related engineering construction.

The object of the present invention is achieved like this: the concrete steps of this analysis method are as follows:

Step 1. Using a mold that can be anchored, prepare pre-cracked samples with different anchorages, and perform random speckle processing on the surface of the samples;

Step 2. Paste 6 to 8 acoustic emission sensors on the surface of the anchored sample in an incompletely coplanar manner, and bond them with a medical couplant to ensure good signal transmission and acquisition;

Step 3. Aim the high-definition digital camera at the crack surface of the sample, and adjust the focus and fix it;

Step 4. Apply a constant displacement load to different anchored samples. The acoustic emission sensor receives the acoustic emission signals of different anchored samples due to internal damage and crack expansion. At the same time, the digital camera captures the anchored samples during the loading process high-definition photos;

Step 5, extracting the acoustic emission signal parameters in step 4 to obtain characteristic parameters such as ringing count, internal events, amplitude, energy, voltage, rise time and duration of different anchored samples;

Step 6, the high-definition photo taken by the digital camera in step 4 is subjected to photosensitive processing, so that the photo is unified under a consistent light intensity, and displacement and strain calculation are performed;

Step 7. Use the acoustic emission counts extracted in step 5 and the calculated and recognized images in step 6 to quantitatively analyze the crack expansion on the surface of different anchored samples, and use the acoustic emission events extracted in step 5 to damage the interior of different anchored samples and a fracture description;

Step 8. Further process the acoustic emission counts to obtain the "activity coefficient" of the rock, draw the "activity coefficient-time" curves of the evolution process of different anchored samples, and define the different activity periods of the rock under loading process according to the curve; Three-dimensional positioning and mapping of internal events is carried out to determine the location of the damage and fracture area inside the rock; cloud images are drawn according to the calculated images, and the law of crack expansion is obtained by combining the displacement and strain calculated by digital images.

The height of the prepared sample is 160mm, the length is 80mm, the thickness is 80mm, and the crack depth is 60mm. The anchor rod is made of polyoxymethylene fiber rod.

Beneficial effects, due to the adoption of the above scheme, the crack expansion and internal damage and fracture of different anchored samples due to loads can be grasped through acoustic emission detection and image recognition, and the "activity coefficient" and acoustic emission event location can be obtained by exploring acoustic emission parameter analysis It can better provide basic data for the stability of anchorage engineering with complex cracks and provide useful reference for related engineering construction.

Description of drawings

Fig. 1 is a flowchart of the analysis method of the present invention.

Fig. 2 is an experimental schematic diagram of the analysis method of the present invention.

Fig. 3 is a diagram showing the relationship between the identification of the active period of the anchored sample according to the present invention and the change over time.

Fig. 4 is a diagram showing the relationship between the image recognition displacement evolution of the anchored sample according to the present invention as a function of time.

Fig. 5 is a diagram showing the evolution of acoustic emission positioning of the anchored sample according to the present invention as a function of time.

Among them, 1. Stress and strain acquisition system; 2. Loading system; 3. Anchor sample; 4. Anchor rod; 5. Crack in anchor sample; 6. Acoustic emission sensor; 7. Acoustic emission control system; 8. Signal amplifier 9. Data transmission line; 10. Image acquisition control system; 11. Digital camera.

Detailed ways

An analysis method for locating anchored rock mass fissure expansion based on image recognition and acoustic emission provided by the present invention will be described in detail below in conjunction with the accompanying drawings and specific embodiments.

The present invention provides an analysis method based on image recognition and acoustic emission to locate the expansion of anchored rock mass fissures. The analysis process and experimental diagram are shown in Figures 1 and 2, respectively, and are specifically implemented through the following steps:

Step 1. Using an anchorable mold, first pre-set the crack 5 on the sample, and then reinforce the anchor rod 4 to prepare different anchoring pre-crack anchoring samples 3, and perform random speckle processing on the surface of the sample;

Step 2. Paste 6 to 8 acoustic emission sensors 6 on the anchoring sample 3 in FIG. 2 , and use a medical acoustic wave coupling agent to bond the acoustic emission sensors and the anchoring sample to keep the contact in good condition;

Step 3. Use the digital camera 11 to align the crack surface of the sample, and perform focus adjustment and fixation. The digital camera 11 is not allowed to be moved during the loading process;

Step 4. Place the anchored sample with the acoustic emission sensor attached on the loading system 1 shown in Figure 2, and apply loads to the anchored sample with different cracks, and collect data through the stress and strain acquisition system 2; make the acoustic emission sensor 6 Receive the acoustic emission signals generated during the loading process of different anchored samples, and input the signals into the acoustic emission control system 7 through the signal amplifier 8 and the data transmission line 9 for processing; at the same time, use the image acquisition control system 10 to analyze during the loading process High-resolution photos of anchored samples in different periods.

Step 5. Extract the acoustic emission signal parameters in step 4 to obtain the characteristic parameters such as ringing count, internal event, amplitude, energy, voltage, rise time and duration of different anchored samples; process the ringing count , get the cumulative ringing count and "activity coefficient", and judge the activity degree of crack evolution during the loading process, as shown in Figure 3. 4 corresponds to the points marked in Fig. 5), according to the "activity coefficient", the anchored sample can be divided into a stable period, an active period and a decay period. Anchor strengthening stage.

Step 6. Perform photosensitive processing on the high-definition photos taken by the digital camera in step 4, so that the photos are unified under a consistent light intensity, and the displacement and strain calculations are performed to obtain the image recognition strain evolution image of the calculation area of the anchored sample, as shown in the figure 4.

Step 7. Use the acoustic emission counting and image recognition extracted in step 5 to quantitatively analyze the crack expansion on the surface of different anchored samples. It is found that the strain of the anchored sample is mainly concentrated at the tip of the crack and the joint between the anchor rod and the crack; The internal events extracted in step 5 describe the internal damage and fracture of different anchored samples, and draw the relationship diagram of the evolution of acoustic emission positioning of the anchored sample with time, as shown in Figure 5. The damage and fracture of the anchored cracked sample are found Most of the situation is concentrated in the upper part of the crack.

Step 8. Further process the acoustic emission counts to obtain the "activity coefficient" of the rock, draw the "activity coefficient-time" curves of the evolution process of different anchored samples, and define the different activity periods of the rock under loading process according to the curve; Three-dimensional positioning and mapping of internal events is carried out to determine the location of the damage and fracture area inside the rock; cloud images are drawn according to the calculated images, and the law of crack expansion is obtained by combining the displacement and strain calculated by digital images.

The height of the prepared sample is 160mm, the length is 80mm, the thickness is 80mm, and the crack depth is 60mm. The anchor rod is made of polyoxymethylene fiber rod.

Claims (2)

1. An analysis method based on image recognition and acoustic emission positioning anchored rock mass crack expansion, characterized in that: a. Using a mold that can be anchored, prepare pre-cracked samples with different anchorages, and perform random speckle treatment on the surface of the samples; b. Paste 6~8 acoustic emission sensors on the surface of the anchored sample according to the incomplete coplanar method, and bond them with medical couplant to make them transmit and collect signals well; c. Aim the high-definition digital camera at the crack surface of the sample, and adjust the focus and fix it; d. Apply a constant displacement load to different anchored samples, and the acoustic emission sensor receives the acoustic emission signals generated by different anchored samples due to internal damage and crack expansion. At the same time, the digital camera captures the high clear photo; e. Extract the parameters of the acoustic emission signal in step d to obtain the ringing count, internal events, amplitude, energy, voltage, rise time and duration of different anchored samples; f. Carry out photosensitive processing to the high-definition photos taken by the digital camera in step d, so that the photos are unified under a consistent light intensity, and displacement and strain calculation are performed; g. Select the ringing count extracted in step e and the image obtained by calculating the displacement and strain of the high-definition photo that has been photosensitive processed in step f to carry out quantitative analysis on the crack expansion on the surface of different anchored samples, and select the image extracted in step e The internal events of different anchorage specimens are described for damage and fracture; h. Further process the ringing count to obtain the "activity coefficient" of the rock, draw the "activity coefficient-time" curve diagram of the evolution process of different anchored samples, and define the different activity periods of the rock loading process according to the curve; the extracted internal Three-dimensional positioning and mapping of the event is carried out to determine the location of the damaged and fractured area inside the rock; cloud images are drawn based on the calculated images, and the law of crack expansion is obtained by combining the displacement and strain calculated by the digital images. 2. a kind of analysis method based on image recognition and acoustic emission location anchorage rock mass fissure expansion according to claim 1, is characterized in that: the sample height of making is 160mm, and length is 80mm, and thickness is 80mm, and fissure depth It is 60mm, and the material used for the anchor rod is polyoxymethylene fiber rod.