Coal roadway tunneling coal and rock dynamic disaster monitoring acoustic emission sensor arrangement method

Abstract

The present application relates to a kind of coal roadway driving coal and rock dynamic disaster monitoring acoustic emission sensor layout method, belong to coal mine safety field.Select coal roadway driving face below floor roadway as the construction roadway of monitoring drill hole;If not have floor roadway condition or coal seam group mining condition, floor roadway and coal roadway driving face distance exceeds 80m, then select adjacent section of the monitoring drill hole of having penetrated coal roadway construction.Monitoring drill hole construction roadway is ahead of coal roadway driving face front coal seam roof, monitoring drill hole trajectory avoids roadway contour range, final hole point is controlled in the coal seam roof strata of coal roadway to be excavated, and acoustic emission sensor is installed to hole bottom.The method lays out sensor, does not affect coal roadway driving face normal excavation, and can guarantee monitoring effect;For different mine roadway layout condition, propose universal sensor layout mode;While multiple acoustic emission sensors can be laid ahead, improve installation efficiency, guarantee monitoring system operation continuity.

Description

Technical Field

[0001] This invention belongs to the field of coal mine safety and relates to a method for deploying acoustic emission sensors for monitoring coal and rock dynamic disasters during coal roadway excavation. Background Technology

[0002] During coal roadway excavation, factors such as the instability of coal seam occurrence conditions, the variability of stress peak values, and the existence of certain blind spots in advance detection lead to a high probability of coal and rock dynamic disasters occurring at the coal roadway excavation face. Therefore, there is an urgent need for on-site monitoring methods for coal and rock dynamic disasters.

[0003] The "Detailed Rules for the Prevention and Control of Coal and Gas Outbursts" stipulate that, in order to make the prediction of working faces more reliable, mines are encouraged to add some auxiliary prediction indicators according to actual conditions, such as combining acoustic emission with geophysical exploration, drilling and other methods for comprehensive prediction. Therefore, applying acoustic emission technology to the monitoring of coal and rock dynamic disasters in mines will be an important technical means and will also promote the safe and efficient production of coal mines. The method of deploying acoustic emission sensors at the coal roadway excavation face has an important impact on the monitoring effect and the daily tunneling efficiency of the mine. If the sensors are directly deployed at the coal roadway excavation face, the tunneling, roadway support and drainage monitoring borehole construction will inevitably generate a large number of interference signals and affect the monitoring effect. If the sensors are installed by deploying monitoring boreholes in the construction layer at the excavation face, it will affect the daily tunneling and production, and it is impossible to continuously and proactively deploy multiple sets of sensors, which does not meet the needs of intelligent mine development.

[0004] The prior art “CN111679330A” discloses an integrated sensor and a method for monitoring during tunneling for electromagnetic wave geological imaging and acoustic emission monitoring. However, this method cannot be implemented when the conditions of the bottom roadway are not met or the distance between the bottom roadway and the coal roadway tunneling face exceeds 80m under the conditions of coal seam group mining.

[0005] Therefore, in order to ensure the reliability of monitoring during tunneling and the continuous and efficient tunneling of coal roadways, a scientific method for deploying acoustic emission sensors for advanced monitoring of coal and rock dynamic disasters during tunneling is the foundation and key to achieving this goal. Summary of the Invention

[0006] In view of this, the purpose of the present invention is to provide a method for deploying acoustic emission sensors for monitoring coal and rock dynamic disasters in coal roadway excavation.

[0007] To achieve the above objectives, the present invention provides the following technical solution:

[0008] A method for deploying acoustic emission sensors for monitoring coal and rock dynamic hazards during coal roadway excavation, comprising the following steps:

[0009] S1: Confirm the construction roadway of the monitoring borehole;

[0010] S2: Establish coal seam occurrence parameters such as coal seam dip angle, coal seam thickness, and coal firmness coefficient in the coal roadway excavation face; calculate monitoring borehole construction parameters such as monitoring borehole dip angle, monitoring borehole length, monitoring borehole diameter, and monitoring borehole spacing.

[0011] S3: Based on the construction parameters of the construction roadway and monitoring borehole selected by S1 and S2, construct the monitoring borehole. After the monitoring borehole is completed, install and fix the acoustic emission sensor (4) at the bottom of the monitoring borehole, leave one end of the signal line (2) outside the monitoring borehole, and seal the end of the monitoring borehole opening with malathion to isolate the noise in the roadway.

[0012] S4: Connect the signal line (2) left outside the hole in S3 to the signal acquisition host of the monitoring system to realize the acquisition and grid transmission of the monitoring signal of the acoustic emission sensor in the hole. The monitoring system monitors the coal and rock dynamic disasters during excavation based on the real-time continuous signal and completes the deployment of the acoustic emission sensor.

[0013] In S1, the specific construction roadway for confirming the monitoring borehole is as follows: if there is a bottom roadway below the coal roadway excavation face, and the relative distance between the bottom roadway and the coal roadway excavation face does not exceed 80m, then the monitoring borehole is arranged in the bottom roadway; otherwise, the monitoring borehole is selected in the adjacent section of the already connected coal roadway.

[0014] Optionally, in S2, the method for determining the inclination angle and length of the monitoring borehole is as follows: the monitoring borehole is constructed from the monitoring borehole construction roadway to the coal seam roof (3) of the coal roadway excavation face. The trajectory of the monitoring borehole avoids the outline of the excavation roadway and the distance between the monitoring borehole and the roadway outline is controlled within 1m. The end point of the monitoring borehole is controlled in the rock strata of the coal seam roof (3) of the coal roadway to be excavated, and the inclination angle and length of the monitoring borehole are calculated.

[0015] Optionally, in S2, the borehole diameter is determined by the borehole diameter of the acoustic emission sensor (4) complete set of equipment, and the borehole spacing is monitored. M The calculation formula is:

[0016]

[0017] In the formula, The coal firmness coefficient at the coal face during coal roadway excavation. C It is the ratio of the minimum amplitude of the acoustic emission signal inside the coal and rock mass that can be received and recognized to the initial amplitude;

[0018] ratio C The stress loading experiment or effective empirical value is established by collecting coal samples from the coal roadway excavation face and conducting stress loading experiments or other experiments in the laboratory.

[0019] Optionally, in S3, the tail end of the acoustic emission sensor is equipped with an elastic fixing claw mechanism (1) to ensure that the acoustic emission sensor (4) is in contact with the hole wall and is fixedly installed at the bottom of the hole.

[0020] Optionally, in S3, the sealing depth at the borehole opening is determined based on the size of the pressure relief ring, with a minimum depth range of 12–15 m.

[0021] The beneficial effects of this invention are as follows: By installing the acoustic emission sensor inside the monitoring borehole, the impact of roadway construction work on the monitoring signal can be minimized. Furthermore, the relatively low daily operations in the bottom roadway further reduce interference, making bottom roadway construction of the monitoring borehole preferable. The monitoring borehole avoids the tunneling outline and is controlled within 1 meter, preventing safety hazards caused by scraping between the roadheader and the acoustic emission sensor and signal lines during coal roadway excavation. It also maximizes the proximity of the acoustic emission sensor to the tunneling roadway, ensuring sufficient signal acquisition. Installing the sensor in the dense roof strata of the coal seam increases the signal acquisition range and reduces interference from coal seam deformation and borehole tampering. Moreover, by constructing monitoring boreholes in the bottom roadway or adjacent roadways, multiple sets of monitoring boreholes can be deployed in advance without affecting daily tunneling and support operations at the coal roadway face, achieving continuous monitoring of the coal roadway during excavation and ultimately ensuring efficient and continuous mine production.

[0022] Other advantages, objectives, and features of the invention will be set forth in part in the description which follows, and in part will be apparent to those skilled in the art from the following examination, or may be learned from practice of the invention. The objectives and other advantages of the invention can be realized and obtained through the following description. Attached Figure Description

[0023] To make the objectives, technical solutions, and advantages of the present invention clearer, the preferred embodiments of the present invention will be described in detail below with reference to the accompanying drawings, wherein:

[0024] Figure 1 This is a flowchart illustrating the installation and layout of the acoustic emission sensor of the present invention.

[0025] Figure 2 This is a cross-sectional view of the method for deploying borehole sensors for monitoring the bottom tunnel of the present invention;

[0026] Figure 3 This is a cross-sectional view of the method for deploying borehole sensors for monitoring adjacent roadways according to the present invention;

[0027] Figure 4 This is a schematic diagram of the advanced deployment of the acoustic emission sensor of the present invention.

[0028] Reference numerals: 1-Elastic fixed claw mechanism, 2-Signal line, 3-Coal seam roof, 4-Acoustic emission sensor. Detailed Implementation

[0029] The following specific examples illustrate the implementation of the present invention. Those skilled in the art can easily understand other advantages and effects of the present invention from the content disclosed in this specification. The present invention can also be implemented or applied through other different specific embodiments, and various details in this specification can be modified or changed based on different viewpoints and applications without departing from the spirit of the present invention. It should be noted that the illustrations provided in the following embodiments are only schematic representations of the basic concept of the present invention. Unless otherwise specified, the following embodiments and features can be combined with each other.

[0030] The accompanying drawings are for illustrative purposes only and are schematic diagrams, not actual pictures. They should not be construed as limiting the invention. To better illustrate the embodiments of the invention, some parts in the drawings may be omitted, enlarged, or reduced, and do not represent the actual product dimensions. It is understandable to those skilled in the art that some well-known structures and their descriptions may be omitted in the drawings.

[0031] In the accompanying drawings of the embodiments of the present invention, the same or similar reference numerals correspond to the same or similar components. In the description of the present invention, it should be understood that if terms such as "upper," "lower," "left," "right," "front," and "rear" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the drawings, they are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, the terms used to describe positional relationships in the drawings are only for illustrative purposes and should not be construed as limiting the present invention. For those skilled in the art, the specific meaning of the above terms can be understood according to the specific circumstances.

[0032] Please see Figures 1-4 This describes a method for deploying acoustic emission sensors for advanced monitoring of coal and rock dynamic hazards during coal roadway excavation. Figure 2 middle d To monitor the minimum distance between the borehole and the tunnel outline, d ≤1m, Figure 4 middle M The method for determining the mounting spacing of acoustic emission sensors includes the following steps:

[0033] S1: Install acoustic emission sensor 4 in the monitoring borehole. The monitoring borehole corresponds to the construction roadway. The optimal roadway layout conditions and spatial distance parameters between roadways are selected by obtaining the three-dimensional space of the coal roadway excavation face.

[0034] S2: Establish coal seam occurrence parameters such as coal seam dip angle, coal seam thickness, and coal firmness coefficient in the coal roadway excavation face, and design and calculate monitoring borehole construction parameters such as monitoring borehole dip angle, monitoring borehole length, monitoring borehole diameter, and monitoring borehole spacing.

[0035] S3: Based on the construction roadway selected in S1 and S2 and the established construction parameters of the monitoring borehole, construct the monitoring borehole as required. After the monitoring borehole is completed, install and fix the acoustic emission sensor 4 at the bottom of the hole, leave one end of the signal line 2 outside the hole, and use malathion to seal the end of the monitoring borehole to isolate the interference noise in the roadway.

[0036] S4: Connect the signal line 2 left outside the hole in S3 to the signal acquisition host of the monitoring system to realize the acquisition and grid transmission of the sensor monitoring signal inside the hole. The monitoring system monitors the dynamic disasters of coal and rock as it is excavated based on the real-time continuous signal, thereby completing the sensor deployment.

[0037] The method for determining the construction roadway for monitoring boreholes in S1 is as follows: if there are conditions for a bottom roadway below the coal roadway excavation face, and the relative distance between the bottom roadway and the coal roadway excavation face does not exceed 80m, then monitoring boreholes are selected to be arranged in the bottom roadway; otherwise, monitoring boreholes are selected from the adjacent sections of the already connected coal roadway.

[0038] The method for determining the inclination angle and length of the monitoring borehole in S2 is as follows: The monitoring borehole is constructed from the construction roadway to the coal seam roof 3 in front of the coal roadway excavation face. The trajectory of the monitoring borehole avoids the outline of the excavation roadway and the distance between the monitoring borehole and the roadway outline is controlled within 1m. The end point of the monitoring borehole is controlled in the rock strata of the coal seam roof 3 of the coal roadway to be excavated. The inclination angle and length of the monitoring borehole are calculated from this.

[0039] In S2, the borehole diameter is determined by the diameter of the acoustic emission sensor 4-piece set of equipment; the borehole spacing is monitored in S2. M Determined by the following formula:

[0040]

[0041] In the formula, The firmness coefficient of coal at the coal roadway excavation face. C It is the ratio of the minimum amplitude of the acoustic emission signal inside the coal and rock mass that can be received and recognized to the initial amplitude.

[0042] ratio C The stress loading experiment or effective empirical value is established by collecting coal samples from the coal roadway excavation face and conducting stress loading experiments or other experiments in the laboratory.

[0043] The S3 acoustic emission sensor is equipped with an elastic fixing claw mechanism 1 at the tail end to ensure that the acoustic emission sensor 4 is in full contact with the hole wall and is firmly installed at the bottom of the hole without sliding, thus ensuring that the monitoring signal is true and reliable.

[0044] In S3, the sealing depth at the borehole opening is determined based on the actual size of the pressure relief ring, with a minimum depth range of 12~15m.

[0045] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit it. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can be made to the technical solutions of the present invention without departing from the spirit and scope of the present invention, and all such modifications or substitutions should be covered within the scope of the claims of the present invention.

Claims

1. A method for deploying acoustic emission sensors for monitoring coal and rock dynamic disasters during coal roadway excavation, characterized in that: The method includes the following steps: S1: Confirm the construction roadway of the monitoring borehole; S2: Establish coal seam occurrence parameters such as coal seam dip angle, coal seam thickness, and coal firmness coefficient in the coal roadway excavation face; calculate monitoring borehole construction parameters such as monitoring borehole dip angle, monitoring borehole length, monitoring borehole diameter, and monitoring borehole spacing. S3: Based on the construction parameters of the construction roadway and monitoring borehole selected by S1 and S2, construct the monitoring borehole. After the monitoring borehole is completed, install and fix the acoustic emission sensor (4) at the bottom of the monitoring borehole, leave one end of the signal line (2) outside the monitoring borehole, and seal the end of the monitoring borehole opening with malathion to isolate the noise in the roadway. S4: Connect the signal line (2) left outside the hole in S3 to the signal acquisition host of the monitoring system to realize the acquisition and grid transmission of the monitoring signal of the acoustic emission sensor in the hole. The monitoring system monitors the coal and rock dynamic disasters during excavation based on the real-time continuous signal and completes the deployment of the acoustic emission sensor. In S1, the specific construction roadway for confirming the monitoring borehole is as follows: if there is a bottom roadway below the coal roadway excavation face, and the relative distance between the bottom roadway and the coal roadway excavation face does not exceed 80m, then the monitoring borehole is arranged in the bottom roadway; otherwise, the monitoring borehole is selected in the adjacent section of the already connected coal roadway. In S2, the method for determining the inclination angle and length of the monitoring borehole is as follows: the monitoring borehole is constructed from the construction roadway to the coal seam roof (3) of the coal roadway excavation face. The trajectory of the monitoring borehole avoids the outline of the excavation roadway and the distance between the monitoring borehole and the roadway outline is controlled within 1m. The final point of the monitoring borehole is controlled in the rock strata of the coal seam roof (3) of the coal roadway to be excavated. The inclination angle and length of the monitoring borehole are calculated. In S2, the borehole diameter is determined by the borehole diameter of the acoustic emission sensor (4) complete set of equipment, and the borehole spacing is monitored. M The calculation formula is: In the formula, The coal firmness coefficient at the coal face during coal roadway excavation. C It is the ratio of the minimum amplitude of the acoustic emission signal inside the coal and rock mass that can be received and recognized to the initial amplitude; ratio C The stress loading experiment or effective empirical value is established by collecting coal samples from the coal roadway excavation face and conducting stress loading experiments or other experiments in the laboratory. In S3, the tail end of the acoustic emission sensor is equipped with an elastic fixing claw mechanism (1) to ensure that the acoustic emission sensor (4) is in contact with the hole wall and is fixedly installed at the bottom of the hole; In S3, the sealing depth at the borehole opening is determined based on the size of the pressure relief ring, with a minimum depth range of 12 to 15 m.

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