Intelligent early warning method for stress-displacement roof catastrophe

Abstract

The invention discloses a stress-displacement roof catastrophe intelligent early warning method, and relates to the technical field of coal mine engineering safety and supporting. The method comprises the following steps: firstly, respectively establishing a stress-time database and a displacement-time database according to a relationship between stress and time of a roof separation layer and a relationship between displacement and time of the roof separation layer, and respectively setting four early warning modules in the corresponding databases; then stress-time and displacement-time are collected in real time through a sensor, and collected data are transmitted to a corresponding data processor; after being processed by the data processor, the data are uploaded to the stress-time database and the displacement-time database, are dynamically matched with the four early warning modules in each database, and then are converted to generate early warning signals for early warning. According to the method, the principle of stress-displacement synchronization is followed, and the accuracy of early warning is remarkably improved through double monitoring means and comprehensive monitoring of the roof separation stress and displacement.

Description

Technical Field

[0001] The present invention relates to the field of coal mine engineering safety and support technology, and in particular to a "stress-displacement" roof disaster intelligent early warning method. Background Art

[0002] In the process of coal resource mining, the stability of the tunnel roof is crucial to safe production. As the stress of the tunnel surrounding rock is continuously redistributed, local delamination and deformation occur in the roof, which may cause safety accidents such as roof collapse in severe cases. In order to ensure the stability of the roof, anchor (cable) support is currently mainly used, and most of the existing monitoring methods monitor the stress state of the anchor (cable) or the deformation of the roof with a single parameter. After obtaining the monitoring data, the data cannot be effectively utilized due to the lack of corresponding judgment criteria. Therefore, it is necessary to establish a corresponding early warning model to perform real-time matching and analysis of the collected data, accurately judge the state of the roof, capture the multi-level change process of the roof, and provide accurate early warning before the development of delamination and the instability of the anchoring force.

[0003] Application No. 201911170436.4 discloses a deep well soft coal rock burst disaster monitoring and early warning system and its early warning method. By setting a stress sensor for detecting the pressure value of the borehole and a displacement sensor for detecting the displacement value generated when the tunnel wall is deformed, three stress warning signals, namely the first green warning, the first yellow warning and the first red, and two preset warning pressure values, namely the first warning pressure value and the second warning pressure value, are set, as well as three displacement warning signals, namely the second green warning, the second yellow warning and the second red warning, and two preset warning pressure values, namely the first warning pressure value and the second warning pressure value, respectively. The stress warning indicator issues a corresponding stress warning according to the displacement value, so that the warning can be issued based on the comprehensive data of the borehole pressure value and the deformation of the tunnel.

[0004] The above-mentioned prior art realizes early warning by monitoring the pressure value and the displacement value, but its early warning method emphasizes the threshold warning based on the pressure value, and does not clearly point out the relationship between stress and displacement changes. However, displacement and stress can change synchronously on site. For example, under specific geological conditions (such as soft rock tunnels, deep mining environments, and local pressure relief areas), the stress and displacement of the coal mine roof can show the characteristics of synchronous changes. Specifically, when the stress on the roof rock layer reaches a certain level, stress redistribution and deformation response occur almost simultaneously. Therefore, for the situation where stress and displacement change synchronously, the prediction method of the prior art is not feasible, and its prediction accuracy needs to be further improved. Summary of the invention

[0005] The purpose of the present invention is to provide a "stress-displacement" roof disaster intelligent early warning method, which follows the principle of "stress-displacement" synchronization and significantly improves the accuracy of early warning through dual monitoring means and comprehensive monitoring of roof delamination stress and displacement.

[0006] In order to achieve the above-mentioned purpose, the present invention adopts the following technical scheme: a "stress-displacement" roof disaster intelligent early warning method, comprising the following steps: (1) establishing a stress-time database and a displacement-time database respectively through the relationship between the stress and time of roof delamination and the relationship between the displacement and time of roof delamination.

[0007] (2) The stress-time and displacement-time are collected in real time through sensors, and the collected data are transmitted to the corresponding data processor.

[0008] (3) Four early warning modules are set in the stress-time database, namely, stress stability module, stress slow development module, stress delamination development module and stress delamination instability module. The stress stability module means that the anchoring force does not change with time, the stress slow development module means that the anchoring force increases slowly with time, the stress delamination development module means that the anchoring force increases in a jump-like manner, and the stress delamination instability module means that the anchoring force decreases abruptly.

[0009] Four early warning modules are provided in the displacement-time database, namely, an overall stability module, a separation layer development module 1, a separation layer development module 2 and a separation layer instability module. The overall stability module means that the displacement deformation does not change with time, the separation layer development module 1 means that the displacement deformation increases slowly and then tends to stabilize, the separation layer development module 2 means that the displacement deformation increases in a jump-like manner, and the separation layer instability module means that the displacement deformation increases sharply exponentially.

[0010] (4) After the data is processed by the data processor, it is uploaded to the stress-time database and the displacement-time database, dynamically matched with the four warning modules in each database, and then transformed to generate warning signals for warning.

[0011] In the above-mentioned "stress-displacement" intelligent early warning method for roof disasters, in step (2), a sensor is installed on an anchor rod or an anchor cable, and the anchor rod or the anchor cable is arranged in the tunnel roof; the sensor includes a stress sensor and a displacement sensor, and the stress sensor is used to collect stress-time data in real time, and the displacement sensor is used to collect displacement-time data in real time.

[0012] In the above-mentioned "stress-displacement" intelligent early warning method for roof disasters, in step (2), a borehole is arranged in the roof rock layer of the tunnel, the anchor rod or anchor cable is installed in the borehole, and the stress sensor is fixed to the end of the anchor rod or anchor cable.

[0013] In the above-mentioned "stress-displacement" intelligent early warning method for roof disasters, in step (3), it is converted into an early warning signal and issued through an early warning release terminal.

[0014] In the above-mentioned "stress-displacement" intelligent early warning method for roof disasters, in step (3), the stress stability module indicates that the roof rock layer is stable; the stress slow development module indicates that the roof rock layer support system begins to be stressed and needs to be monitored and observed; the stress separation layer development module indicates that the roof rock layer structure changes dramatically and there are hidden dangers; the stress separation layer instability module indicates that the support system fails and the danger level is high.

[0015] In the above-mentioned "stress-displacement" intelligent early warning method for roof disasters, in step (3), the overall stability module indicates that there is no obvious delamination of the roof rock layer; the delamination development module 1 indicates that the rock layer has slight deformation, but is in a controllable state; the delamination development module indicates that the delamination develops rapidly and the risk of instability increases; the delamination instability module indicates that the instability trend of the rock layer is aggravated and the risk of collapse is high.

[0016] Compared with the prior art, the present invention brings the following beneficial technical effects: (1) Through the comprehensive monitoring of roof delamination stress and displacement, a comprehensive analysis of the support system and rock formation status is achieved, which makes up for the limitations of traditional single monitoring methods and significantly improves the accuracy of early warning.

[0017] (2) This method divides the monitoring results into eight detailed situations, which can more accurately determine the status of the roof and predict the trend and risk of roof deformation and instability.

[0018] (3) This method can flexibly adjust the monitoring strategy and model threshold according to the changes in geological conditions and is suitable for a variety of environments such as soft rock, hard rock and deep mining.

[0019] (4) The present invention provides a scientific basis for mine management personnel to make decisions, reduces casualties and equipment damage caused by accidents such as collapse, and thus ensures safe production in mines. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 Schematic diagram of the layout of roof delamination disaster under stress-time monitoring.

[0021] Figure 2 These are graphic analysis diagrams of four early warning modules, among which (a) is the graphic analysis diagram of the stress stability module; (b) is the graphic analysis diagram of the stress slow development module; (c) is the graphic analysis diagram of the stress detachment development module; and (d) is the graphic analysis diagram of the stress detachment instability module.

[0022] Figure 3 Schematic diagram of the layout of roof delamination disaster under displacement-time monitoring.

[0023] Figure 4 The following are graphic analysis diagrams of four early warning modules, among which (a) is the graphic analysis diagram of the overall stability module; (b) is the graphic analysis diagram of the delamination development module one; (c) is the graphic analysis diagram of the delamination development module two; and (d) is the graphic analysis diagram of the delamination instability module.

[0024] Figure 5 Schematic diagram of the intelligent early warning method for roof delamination disaster.

[0025] In the figure: 1-stress sensor; 2-borehole; 3-roof rock layer; 4-coal seam; 5-tunnel; 6-anchor rod; 7-four warning modules in stress-time database; 71-stress stability module; 72-stress slow development module; 73-stress detachment development module; 74-stress detachment instability module; 8-deep anchor point of displacement sensor; 9-four warning modules in displacement-time database; 91-overall stability module; 92-detachment development module one; 93-detachment development module two; 94-detachment instability module; 10-shallow anchor point of displacement sensor; 11-displacement sensor; 12-stress-time database and displacement-time database; 13-warning release terminal. DETAILED DESCRIPTION

[0026] The technical solutions in the embodiments of the present application will be clearly and completely described below in conjunction with the drawings in the embodiments of the present application.

[0027] In the description of this application, words such as "one", "two", etc. are only used to distinguish different objects, and do not limit the quantity and execution order, and words such as "one", "two", etc. do not necessarily limit differences. In addition, the terms "including" and "having" and any variations thereof are intended to cover non-exclusive inclusions.

[0028] The technical solution of the present application is further described in detail below in conjunction with the accompanying drawings.

[0029] The main technical concept of the present application is that after the collected data is processed by the stress sensor 1 and the displacement sensor 11, it is input into the four warning modules 7 in the stress-time database and the four warning modules 9 in the displacement-time database for dynamic matching. It monitors stress-time and displacement-time synchronously, which is different from the sequential monitoring method in the prior art. By analyzing the judgment and graphics of the four warning modules, the stable state of the roof, the delamination development process and the instability situation can be identified.

[0030] Combination Figure 1 to Figure 5 As shown, the present invention provides a "stress-displacement" roof disaster intelligent early warning method, comprising the following steps:

[0031] The first step is to arrange the stress sensor 1 and the displacement sensor 11. Figure 1 A tunnel 5, a coal seam 4, and a roof rock layer 3 are shown in the figure. A borehole 2 is arranged in the roof rock layer 3 of the tunnel 5, an anchor rod 6 is installed in the borehole 2, and a stress sensor 1 is fixed to the end of the anchor rod 6 to collect stress data in real time.

[0032] A deep anchor point 8 of the displacement sensor is installed at a deep position of the borehole 2, a shallow anchor point 10 of the displacement sensor is installed at a shallow position of the borehole 2, and a displacement sensor 11 is fixed outside the borehole 2 to collect displacement data in real time.

[0033] The second step is to construct a stress-time database and a displacement-time database 12, and establish corresponding databases through eight warning modules under the stress-time and displacement-time relationships. The stress sensor 1 and the displacement sensor 11 collect stress-time and displacement-time data in real time and upload them to the data processor, dynamically match the uploaded data in the eight warning modules, judge the state of the roof and evaluate it, and finally use the warning release terminal 13 to release the warning signal.

[0034] The eight warning modules mentioned above specifically include four types of stress-time and four types of displacement-time, as follows: Figure 2 As shown, the four warning modules 7 in the stress-time database include a stress stability module 71, a stress slow development module 72, a stress separation development module 73, and a stress separation instability module 74. Among them, the stress stability module 71 is that the stress value remains constant, and the figure is a horizontal straight line, indicating that the top rock layer 3 is stable and there is no risk; the stress slow development module 72 is that the stress gradually increases from a constant state, and the horizontal straight line in the figure is followed by an oblique rise, indicating that the rock support system begins to be stressed and requires enhanced monitoring and observation; the stress separation development module 73 is that the stress suddenly increases, and the straight line changes in a jump-like manner, indicating that the rock structure changes dramatically and there may be safety hazards; the stress separation instability module 74 is that the stress drops abruptly, and the straight line drops suddenly, indicating that the support system fails and may collapse, and the danger level is the highest.

[0035] The four warning modules 9 in the displacement-time database include an overall stability module 91, a separation development module 1 92, a separation development module 2 93, and a separation instability module 94; the overall stability module 91 is that the displacement difference between the deep anchor point and the shallow anchor point remains constant as a whole, and the figure is a horizontal straight line, indicating that there is no obvious separation in the top rock layer 3 and there is no danger; the separation development module 1 92 is that the displacement difference between the deep anchor point and the shallow anchor point increases slightly and then tends to be stable, indicating that the rock layer has slight deformation, but is still in a controllable state and the danger level is low; the separation development module 2 93 is that the displacement difference between the deep anchor point and the shallow anchor point increases suddenly, and the curve rises in a jump-like manner, indicating that the separation develops rapidly and needs to be paid attention to, and the risk of instability increases; the separation instability module 94 is that the displacement difference between the deep anchor point and the shallow anchor point increases exponentially, indicating that the instability trend of the rock layer is aggravated and the risk of collapse is extremely high.

[0036] The four early warning modules 7 in the stress-time database include a stress stability module 71, a stress slow development module 72, a stress separation layer development module 73, and a stress separation layer instability module 74, wherein the determination method of each module is as follows.

[0037] Stress stabilization module 71: stress change rate (ΔF / Δt) ≤ 0.05 kN / min.

[0038] Stress slow development module 72: 0.05MPa / min<ΔF / Δt≤0.2kN / min.

[0039] Stress detachment layer development module 73: 0.2kN / min<ΔF / Δt≤0.5kN / min.

[0040] Stress separation instability module 74: ΔF / Δt>0.5kN / min, or the stress value drops significantly.

[0041] ΔF / Δt represents the change in anchoring force per unit time (i.e. Figure 2 The slope of the middle curve).

[0042] The four warning modules 9 in the displacement-time database include an overall stability module 91, a separation layer development module 1 92, a separation layer development module 2 93, and a separation layer instability module 94, wherein the determination method of each module is as follows.

[0043] Overall stabilization module 91: displacement rate (ΔS / Δt) ≤ 0.01 mm / min.

[0044] Abscission layer development module 192: 0.01mm / min<ΔS / Δt≤0.1mm / min.

[0045] Abscission layer development module 2 93: 0.1mm / min<ΔS / Δt≤3mm / min.

[0046] Delamination instability module 94: ΔS / Δt>0.3mm / min.

[0047] ΔS / Δt represents the change in the displacement of the separation layer per unit time (i.e. Figure 4 mid-curve slope).

[0048] Secondly, dynamic matching is carried out to realize “stress-displacement synchronous monitoring” based on real-time data acquisition, preprocessing, matching algorithm and state judgment.

[0049] Dynamic matching is to identify the roof state by matching real-time data with the characteristic curves of the modules in the stress-time database and displacement-time database. The specific process is as follows.

[0050] Data preprocessing: normalize and perform sliding average processing on the collected stress and displacement data to eliminate noise interference.

[0051] Matching algorithm: Use the dynamic time warping (DTW) algorithm in the existing technology to match the real-time data curve with the eight warning module characteristic curves and calculate the matching degree.

[0052] State determination: Determine the current state of the roof according to the module with the highest matching degree, and verify the result in combination with quantitative standards. The specific steps are: First, single parameter determination: match stress with the module in the stress-time database, and match displacement with the module in the displacement-time database to obtain the single parameter matching result. Second, comprehensive determination: conduct a comprehensive evaluation of the matching results of stress and displacement: if the matching states of the two are consistent, directly determine the current state. If the two states are inconsistent, the state with a higher danger level is the final result.

[0053] If the stress change rate matches the stress stability module 71 in the stress-time database, the stress state is stable at this time; if the displacement rate matches the overall stability module 91 in the displacement-time database, the displacement state is stable at this time; then comprehensively judging, the disaster type of the roof is stable.

[0054] If the stress change rate matches the stress stability module 71 in the stress-time database, the stress state is stable at this time; if the displacement rate matches the abscission development module 92 in the displacement-time database, the displacement state is abscission development one at this time; then comprehensively judging, the disaster type of the roof is abscission development one.

[0055] If the stress change rate matches the stress delamination instability module 74 in the stress-time database, the stress state is unstable at this time; if the displacement rate matches the delamination development module 92 in the displacement-time database, the displacement state is delamination development one at this time; then comprehensively judging, the disaster type of the roof is stress delamination instability.

[0056] In summary, the present invention can monitor stress-time and displacement-time synchronously to obtain more accurate discrimination results. The parts not described in the present invention can be realized by referring to the existing technology.

[0057] Those skilled in the art should recognize that the above embodiments are only used to illustrate the present application and are not intended to be limiting of the present application. As long as they are within the spirit and scope of the present application, appropriate changes and modifications to the above embodiments are within the scope of protection claimed in the present application.

Claims

1. A "stress-displacement" roof disaster intelligent early warning method, characterized in that: The following steps are involved: (1) Based on the relationship between the stress and time of the roof separation layer and the relationship between the displacement and time of the roof separation layer, a stress-time database and a displacement-time database are established respectively; (2) collecting stress-time and displacement-time in real time through sensors, and transmitting the collected data to corresponding data processors; (3) Four early warning modules are set in the stress-time database, namely, a stress stability module, a stress slow development module, a stress separation development module and a stress separation instability module. The stress stability module means that the anchoring force does not change with time, the stress slow development module means that the anchoring force increases slowly with time, the stress separation development module means that the anchoring force increases in a jump-like manner, and the stress separation instability module means that the anchoring force decreases abruptly; Four early warning modules are set in the displacement-time database, namely, overall stability module, separation layer development module 1, separation layer development module 2 and separation layer instability module. The overall stability module means that the displacement deformation does not change with time, the separation layer development module 1 means that the displacement deformation increases slowly and then tends to be stable, the separation layer development module 2 means that the displacement deformation increases in a jump-like manner, and the separation layer instability module means that the displacement deformation increases sharply exponentially; (4) After the data is processed by the data processor, it is uploaded to the stress-time database and the displacement-time database, dynamically matched with the four warning modules in each database, and then transformed to generate warning signals for warning.

2. According to claim 1, a "stress-displacement" roof disaster intelligent early warning method is characterized by: In step (2), the sensor is installed on the anchor rod or anchor cable, and the anchor rod or anchor cable is arranged in the tunnel roof; the sensor includes a stress sensor and a displacement sensor, and the stress sensor collects stress-time data in real time, and the displacement sensor collects displacement-time data in real time.

3. According to claim 2, a "stress-displacement" roof disaster intelligent early warning method is characterized by: In step (2), a borehole is arranged in the roof rock layer of the tunnel, the anchor rod or anchor cable is installed in the borehole, and the stress sensor is fixed to the end of the anchor rod or anchor cable.

4. According to claim 1, a "stress-displacement" roof disaster intelligent early warning method is characterized by: In step (3), it is converted into an early warning signal and issued through an early warning issuing terminal.

5. The "stress-displacement" roof disaster intelligent early warning method according to claim 1 is characterized by: In step (3), the stress stability module indicates that the roof rock layer is stable; the slow stress development module indicates that the roof rock layer support system begins to be stressed and needs to be monitored and observed; the stress separation layer development module indicates that the roof rock layer structure changes dramatically and there are hidden dangers; the stress separation layer instability module indicates that the support system fails and the danger level is high.

6. The "stress-displacement" roof disaster intelligent early warning method according to claim 1 is characterized by: In step (3), the overall stability module indicates that there is no obvious delamination of the top rock layer; the delamination development module 1 indicates that the rock layer has slight deformation, but is in a controllable state; the delamination development module 2 indicates that the delamination develops rapidly and the risk of instability increases; the delamination instability module indicates that the instability trend of the rock layer is aggravated and the risk of collapse is high.

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