Coal seam roof pressure monitoring and analyzing system

Abstract

The invention relates to the technical field of mine safety monitoring, in particular to a coal seam roof pressure monitoring and analyzing system. According to the method, by dynamically extracting the change trend of the rock mass pressure response in the boundary region and combining the displacement change characteristics, the asymmetry of the stress state can be identified, the accurate capture of the abnormal evolution process is realized, and by constructing the space continuity connection path and eliminating jump points and isolated points, the evolution clue path of the fracture trend can be effectively formed; a loading sequence evolution sequence is extracted according to the time sequence difference of pressure and displacement response, the abnormal sorting phenomenon in the loading process is recognized in a complex rock stratum structure, the reversal behavior of the loading sequence relation is accurately positioned, and the loading sequence evolution sequence is obtained by counting the change of the included angle between adjacent vectors and the spatial density index. The caving trend direction of a local area and a concentrated area can be comprehensively judged, and finally a high-resolution stability grading basis is established in a large-range monitoring area.

Description

Technical Field

[0001] The present invention relates to the technical field of mine safety monitoring, and in particular to a coal seam roof pressure monitoring and analysis system. Background Art

[0002] The field of mine safety monitoring technology mainly involves the continuous monitoring and analysis of various safety risk factors in the underground working environment of coal mines, including data collection and evaluation of geological structure changes, mining stress evolution, surrounding rock stability changes, etc., to achieve the prediction of underground safety situation and risk control.

[0003] Among them, the traditional coal seam roof pressure monitoring and analysis system refers to a type of monitoring system used to grasp the pressure evolution of the overlying rock mass of the coal seam under mining disturbance, and to judge the safety risks caused by the uncertainty of the stress state of the rock formation during the activity.

[0004] The traditional coal seam roof pressure monitoring and analysis system mainly relies on single-point monitoring and static data comparison to interpret the pressure state. It lacks the ability to systematically model the spatial distribution structure and evolution trend of stress in the boundary area. When asymmetric conduction or inconsistent displacement response occurs during the rock loading process, it is impossible to timely perceive the abnormal path of the overall structural evolution. In the process of continuous fracture trend development, the existing system finds it difficult to establish spatial continuity between monitoring points, resulting in discrete fragmentary characteristics in trend judgment and path identification deviation. In the scenario where the loading sequence is abnormally reversed, due to the lack of a temporal structure recognition mechanism, conventional monitoring methods are difficult to reveal the potential damage risks brought about by structural reverse loading. For example, in the roof stress concentration area under multi-level mining interference, the traditional system finds it difficult to judge the chaotic evolution of its internal loading sequence, resulting in missed warning windows, affecting the safety of on-site operations and the timeliness of disaster prevention and control. Summary of the Invention

[0005] The purpose of the present invention is to solve the problem of lack of monitoring points in the prior art and to propose a coal seam roof pressure monitoring and analysis system.

[0006] In order to achieve the above object, the present invention adopts the following technical solution: a coal seam roof pressure monitoring and analysis system, the system comprising:

[0007] Stress anomaly identification module: obtains rock pressure data and rock displacement data in the coal seam roof boundary area, identifies the changing trend of rock pressure response at the coal seam roof boundary position, and marks the monitoring point set of boundary stress asymmetry trend;

[0008] Trend path construction module: performs path continuity identification on the boundary stress asymmetric trend monitoring point set, determines the breaking trend in the path extension direction, and constructs a breaking trend path set;

[0009] The sequence abnormality identification module: according to the breaking tendency path set, the loading evolution sequence of the coal seam roof rock stratum is analyzed, and an abnormal area of loading sequence reversal in the coal seam roof structure is identified;

[0010] The collapse tendency monitoring module: the distribution form of the abnormal area of loading sequence reversal is obtained, the extension direction change characteristics of the abnormal area are extracted, and a coal seam roof area collapse tendency monitoring result is obtained.

[0011] The application improves that the boundary stress asymmetric tendency monitoring point set includes monitoring point distribution information, pressure response direction and displacement response amplitude, the breaking tendency path set includes path direction information, path extension length and continuous monitoring point column, the abnormal area of loading sequence reversal includes loading sequence arrangement, peak response time difference and lag response distribution, and the coal seam roof area collapse tendency monitoring result includes tendency direction change, abnormal section form and periodic evolution tendency.

[0012] The application improves that the stress abnormality identification module includes:

[0013] The monitoring data acquisition submodule: the rock mass pressure time series data and rock stratum displacement change rate data of each distribution monitoring point in the coal seam roof monitoring area in the current period are obtained, and a coal seam roof monitoring period data set is obtained;

[0014] The boundary monitoring point identification submodule: according to the layout coordinates of the monitoring points in the coal seam roof synchronous monitoring data set, the monitoring points at the peripheral geometric edges are identified to form a boundary monitoring point set, the horizontal and vertical monitoring point pairs are constructed in combination with the spatial layout between adjacent monitoring points, and a coal seam roof boundary pressure difference sequence is formed;

[0015] The trend abnormality extraction submodule: based on the coal seam roof boundary pressure difference sequence and the rock stratum displacement change rate of the adjacent internal monitoring points of the boundary monitoring points, a cumulative sum control chart algorithm is called to identify the mutation trend of the difference sequence, if the pressure response direction is consistent and the displacement change rate direction is the same and shows mutation, the corresponding area is marked as an abnormal monitoring point, and a boundary stress asymmetric tendency monitoring point set is obtained.

[0016] The application improves that the trend path construction module includes:

[0017] The spatial coordinate extraction submodule: the spatial position of the boundary stress asymmetric tendency monitoring point set is obtained, the distribution coordinates of each monitoring point in the monitoring area coordinate system are analyzed, the coordinate relationship between the monitoring point pairs is extracted, and a coal seam roof tendency monitoring point spatial relationship set is established according to the coordinate distance relationship;

[0018] The path continuity identification submodule: according to the spatial relationship set of the coal seam roof trend monitoring point, a spatial distance table between all monitoring points is constructed, a connection sequence with continuous distance and linear combination is identified in the spatial distance table, the spatial break monitoring point and the branch jump monitoring point are excluded, and a coal seam roof continuous connection path group is output;

[0019] The direction consistency determination submodule: the coordinate sequence of the node monitoring point of each path in the coal seam roof continuous connection path group is called, compared with the set angle interval, a path set with stable extension direction is screened, and a break trend path set is obtained.

[0020] The application improves that the order anomaly identification module comprises:

[0021] The timing parameter extraction submodule: the monitoring point data in the break trend path set is called, the first occurrence time of the rock mass pressure peak value and the starting time of the rock stratum displacement response of each monitoring point are extracted, and a coal seam roof loading response timing pair set is formed;

[0022] The loading order construction submodule: according to the time record of each monitoring point in the coal seam roof loading response timing pair set, the topological structure order of the monitoring point is combined, the loading time sequence of the upstream and downstream monitoring points is compared in turn, and a coal seam roof loading evolution sequence set is obtained.

[0023] The reverse section identification submodule: based on the coal seam roof loading evolution sequence set, the abnormal order situation in the loading behavior is identified, the monitoring point combination with the pressure peak value earlier than the upstream monitoring point and the corresponding displacement response delay is screened, whether the distribution of the monitoring point combination has continuity and aggregation trend is judged, and a loading order reverse abnormal area is obtained.

[0024] The application improves that the collapse trend monitoring module comprises:

[0025] The extension structure construction submodule: the spatial coordinates of the abnormal monitoring points in the loading order reverse abnormal area are called, the connection relationship between adjacent monitoring points is established according to the arrangement order, and a coal seam roof abnormal section extension vector set is formed.

[0026] The direction feature extraction submodule: according to the adjacent vector pair in the coal seam roof abnormal section extension vector set, the included angle change is calculated and the direction deviation degree is judged, the unit area density of the abnormal monitoring points in the corresponding area of the extension path is counted, and a coal seam roof abnormal distribution direction index group is generated.

[0027] The trend result generation submodule: the included angle change feature and the spatial density data in the coal seam roof abnormal distribution direction index group are combined, the consistency and concentration performance of the extension trend of each area are determined, and a coal seam roof regional collapse trend monitoring result is obtained.

[0028] The application further comprises a stability grade evaluation module: according to the coal seam roof area collapse trend monitoring result, the risk grade of the coal seam roof area collapse is divided, and the coal seam roof area stability evaluation result is obtained;

[0029] The coal seam roof area stability evaluation result comprises a risk grade category, an evaluation reference basis and a warning grade state.

[0030] The application further comprises that the stability grade evaluation module comprises:

[0031] A trend index calling sub-module: based on the coal seam roof area collapse trend monitoring result, the angle change range in each monitoring area and the number of abnormal monitoring points in the specified area are extracted, and a coal seam roof trend judgment index group is established;

[0032] A grade rule matching sub-module: according to the coal seam roof trend judgment index group, combined with the stability evaluation parameters set in the current period, the relationship between the two is compared according to the grade boundary standard, and a coal seam roof trend grade division label set is output;

[0033] An evaluation result generating sub-module: based on the coal seam roof trend grade division label set, a grade judgment total table of the current period is constructed, and the coal seam roof area stability evaluation result is obtained.

[0034] Compared with the prior art, the application has the advantages of:

[0035] In the application, by dynamically extracting the change trend of the boundary area rock mass pressure response and combining the displacement change characteristics, the asymmetry of the stress state can be recognized, the abnormal evolution process can be accurately captured, the evolution clue path of the breaking trend can be effectively formed by constructing a spatial continuity connection path and excluding jump points and isolated points, and then the loading sequence evolution sequence can be extracted according to the time sequence difference of the pressure and displacement response, the abnormal ordering phenomenon in the loading process can be recognized in the complex rock structure, the reverse behavior of the loading sequence can be accurately positioned, the angle change between adjacent vectors and the spatial density index can be statistically determined, the collapse trend direction and the concentrated area of the local area can be comprehensively judged, and finally a high-resolution stability grade division basis can be established in a large-scale monitoring area, early warning and grade evaluation of the potential risk area can be realized, the monitoring data utilization efficiency and the recognition accuracy of the dynamic evolution behavior are improved, and the prediction ability and management decision support ability of the roof structure safety risk are enhanced. BRIEF DESCRIPTION OF DRAWINGS

[0036] Figure 1 The system module diagram of the application;

[0037] Figure 2 The system framework diagram of the application;

[0038] Figure 3 It is a schematic diagram of the stress anomaly identification module of the present application;

[0039] Figure 4 It is a schematic diagram of the trend path construction module of the present application;

[0040] Figure 5 It is a schematic diagram of the sequence anomaly identification module of the present application;

[0041] Figure 6 It is a schematic diagram of the collapse trend monitoring module of the present application;

[0042] Figure 7 It is a schematic diagram of the stability grade evaluation module of the present application. DETAILED DESCRIPTION

[0043] In order to make the purpose, technical scheme and advantages of the present application clearer, the present application will be further described in detail below in combination with the drawings and examples. It should be understood that the specific examples described herein are only used to explain the present application and do not limit the present application.

[0044] In the description of the present application, it should be understood that the terms "length", "width", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside" and the like indicate the orientation or positional relationship shown in the drawings, which is only for the convenience of describing the present application and simplifying the description, and does not indicate or imply that the device or element referred to must have a particular orientation, be constructed and operated in a particular orientation, therefore it cannot be understood as a limitation of the present application. In addition, in the description of the present application, the meaning of "a plurality of" is two or more, unless otherwise explicitly and specifically limited.

[0045] Please refer to Figure 1 The present application provides a technical scheme: a coal seam roof pressure monitoring and analysis system, the system comprises:

[0046] The stress anomaly identification module: obtains the rock mass pressure data and rock stratum displacement data of the boundary area of the coal seam roof, identifies the change trend of the rock mass pressure response at the boundary position of the coal seam roof, and marks the boundary stress asymmetric trend monitoring point set;

[0047] The trend path construction module: performs path continuity identification on the boundary stress asymmetric trend monitoring point set, judges the breaking trend in the extension direction of the path, and constructs a breaking trend path set;

[0048] The sequence anomaly identification module: according to the breaking trend path set, analyzes the loading evolution sequence of the coal seam roof rock stratum and identifies the loading sequence reversal abnormal area in the coal seam roof structure;

[0049] caving tendency monitoring module: obtain the distribution form of the loading sequence reversal abnormal area, extract the change characteristics of the extension direction of the abnormal area, and obtain the caving tendency monitoring result of the coal seam roof area;

[0050] The boundary stress asymmetry tendency monitoring point set includes monitoring point distribution information, pressure response direction, and displacement response amplitude. The breakage tendency path set includes path direction information, path extension length, and continuous monitoring point column. The loading sequence reversal abnormal area includes loading sequence arrangement, peak response time difference, and lag response distribution. The coal seam roof area caving tendency monitoring result includes tendency direction change, abnormal section form, and periodic evolution tendency.

[0051] Please refer to Figure 2 and Figure 3 , the stress anomaly identification module includes:

[0052] Monitoring data acquisition submodule: obtain the rock mass pressure time series data and rock stratum displacement rate data of each distributed monitoring point in the coal seam roof monitoring area in the current period, and obtain the coal seam roof monitoring period data set;

[0053] Obtain the rock mass pressure time series data and rock stratum displacement rate data of each distributed monitoring point in the coal seam roof monitoring area in the current monitoring period. In the execution process, first obtain the spatial coordinates of each monitoring point according to the layout map of the monitoring points in the roof area, then query the current period data in the data acquisition system relying on the layout number, and export the pressure change curve of each monitoring point in the last collection period from the database or real-time collection system. The displacement rate can be calculated by dividing the cumulative displacement difference between the two periods by the time interval. For example, the displacement of a monitoring point at t0 is 50 mm, and the displacement at t1 is 56 mm. The displacement rate is (56-50) / (t1-t0) = 6 mm / h. If t1-t0 is 2 hours, the displacement rate is 3 mm / h. Then, the time series data of each monitoring point is unified and formatted, and the coal seam roof period monitoring data set containing spatial number, time stamp, pressure value, and displacement rate is constructed.

[0054] Boundary monitoring point identification submodule: according to the layout coordinates of the monitoring points in the coal seam roof synchronous monitoring data set, identify the monitoring points at the geometric edges of the periphery to form a boundary monitoring point set, combine the spatial layout between adjacent monitoring points to construct horizontal and vertical monitoring point pairs, and form a coal seam roof boundary pressure difference sequence;

[0055] Based on the monitoring point layout coordinates in the coal seam roof synchronous monitoring data set, a two-dimensional plane projection algorithm is first called to project all the three-dimensional coordinates of the monitoring points to the XY plane, and a minimum circumscribed polygon is constructed on the two-dimensional plane or a concave hull algorithm is used to identify the outermost monitoring points as a set of boundary points. For example, in a certain monitoring area, 20 monitoring points are laid out, and after coordinate projection and boundary calculation, 6 monitoring points at the edge are identified, numbered as P1 to P6. Then, according to their numbered positions and adjacency, monitoring point pairs in the horizontal (e.g., X-axis direction) and vertical (Y-axis direction) are established, such as P1 and P2, P3 and P4, P1 and P4, P2 and P5, and the difference in rock mass pressure between the two points in each pair is extracted to construct a boundary pressure difference sequence. For example, in a certain period, the pressure of P1 is 11 MPa and the pressure of P2 is 14 MPa, so the corresponding difference is |14-11| = 3 MPa, and the pressure difference sequence of all boundary point pairs is formed in turn.

[0056] Trend anomaly extraction submodule: Based on the boundary pressure difference sequence of the coal seam roof and the displacement change rate of the adjacent internal monitoring points of the boundary monitoring points, the cumulative sum control chart algorithm is called to identify the mutation trend of the difference value sequence. If the pressure response direction is consistent and the displacement change rate direction is the same and shows mutation, the corresponding area is marked as an abnormal monitoring point, and a set of boundary stress asymmetric trend monitoring points is obtained;

[0057] Based on the pressure difference sequence of the boundary monitoring points of the coal seam roof and the displacement change rate data of the adjacent internal monitoring points, data of multiple monitoring periods are continuously collected to analyze the trend change. For example, the pressure difference values of a certain horizontal boundary monitoring point pair in five consecutive periods are 2.1 MPa, 2.4 MPa, 3.0 MPa, 5.2 MPa, and 6.8 MPa, forming a pressure difference sequence {2.1, 2.4, 3.0, 5.2, 6.8}, and the displacement change rate of the adjacent internal points is {0.8, 0.9, 1.0, 1.5, 2.3} mm / h. The cumulative sum control chart (CUSUM) method is used to detect trend mutation, and the core control formula is as follows:

[0058] S k =max(0,S k-1 +(x k -μ-K'));

[0059] Where S k : the CUSUM cumulative statistical value in the kth monitoring period, used to judge whether a mutation has occurred; S k-1 : the CUSUM value of the previous period (k-1 period), representing the historical cumulative deviation; x k: the observed data point in the kth cycle, here the pressure difference (unit: MPa) of the kth cycle boundary monitoring point pair; μ: the process target value, i.e. the historical observation mean value under normal condition, usually obtained from the mean value of historical data of at least 20 normal cycles; K': the reference value, used to set the deviation that the system can tolerate, generally half of the process standard deviation σ, i.e. K' = 0.5 · σ; max(0, ): used to prevent negative accumulation, making the CUSUM value return to 0 when there is no mutation.

[0060] Suppose that the historical normal cycle data gives an average value μ = 2.5 MPa and a standard deviation σ = 1.0 MPa, then the reference value K' = 0.5 · 1.0 = 0.5 MPa, and the initialization S0 = 0. The CUSUM value of each cycle is calculated according to the following steps:

[0061] Cycle 1: S1 = max(0, S0 + (2.1 - 2.5 - 0.5)) = max(0, 0 + (-0.9)) = 0;

[0062] Cycle 2: S2 = max(0, S1 + (2.4 - 2.5 - 0.5)) = max(0, 0 + (-0.6)) = 0;

[0063] Cycle 3: S3 = max(0, S2 + (3.0 - 2.5 - 0.5)) = max(0, 0 + (0.0)) = 0;

[0064] Cycle 4: S4 = max(0, S3 + (5.2 - 2.5 - 0.5)) = max(0, 0 + (2.2)) = 2.2;

[0065] Cycle 5: S5 = max(0, S4 + (6.8 - 2.5 - 0.5)) = max(0, 2.2 + (3.8)) = 6.0.

[0066] If S k continues to be 0, it means that the current data has no significant deviation from the historical state, and the trend is stable; if S k becomes positive at the beginning of a cycle, it means that the pressure difference of the current cycle has exceeded the tolerance range, and the system starts to accumulate anomalies; if the following S k continues to increase and does not fall to 0 due to "deviation weakening", it means that the abnormal trend is being continuously strengthened, constituting a mutation trend.

[0067] The final CUSUM value of the 5th cycle is S5 = 6.0, which significantly exceeds the set mutation recognition threshold (for example, the empirical value is 5.0), and thus it is judged that a trend mutation has occurred. Then, it is checked whether the displacement change rate of the internal monitoring point also synchronously mutates. The mean value of the displacement change rate calculated from the historical data is the standard deviation σ v= 0.6 mm / h, the mutation threshold is set to While the displacement change rate of the 5th cycle is 2.3 mm / h, which is greater than the threshold and the direction is consistent, it is determined that the boundary point position has a mutation trend of consistent pressure and displacement direction, and it is added to the abnormal trend monitoring point set and records the space number, abnormal time period, CUSUM statistical value and displacement change rate.

[0068] Please refer to Figure 2 and Figure 4 The trend path construction module includes:

[0069] The spatial coordinate extraction submodule: obtain the spatial position of the boundary stress asymmetry trend monitoring point set, analyze the distribution coordinates of each monitoring point in the monitoring area coordinate system, extract the coordinate relationship between the monitoring point pairs, and establish the coal seam roof trend monitoring point spatial relationship set according to the coordinate distance relationship;

[0070] After obtaining the boundary stress asymmetry trend monitoring point set, the actual arrangement coordinates of these monitoring points in the monitoring area need to be further clarified. First, read the number and corresponding coordinates of each monitoring point from the layout data, for example, the coordinates of monitoring point A are 12.5 meters in the horizontal direction and 32.0 meters in the vertical direction, and the coordinates of monitoring point B are 14.0 meters in the horizontal direction and 36.0 meters in the vertical direction. When extracting the coordinate relationship between the two points, calculate the horizontal coordinate difference as 14.0 minus 12.5 equals 1.5 meters, and the vertical coordinate difference as 36.0 minus 32.0 equals 4.0 meters. Then, according to the right angle side length relationship, construct the connection distance between the monitoring points. In this example, it can be understood as a right angle path with a long side of 4.0 meters and a short side of 1.5 meters. By calculating the spatial distance between each point pair, it can be determined which point pairs have a strong spatial correlation. If the distance between two points exceeds the reasonable layout interval (such as 10 meters), the relationship between the points can be excluded. After extracting and calculating the coordinate difference of all monitoring point pairs, record the effective point pairs into the trend monitoring point spatial relationship set.

[0071] The path continuity identification submodule: according to the coal seam roof trend monitoring point spatial relationship set, construct the spatial distance table between all monitoring point pairs, identify the connection sequence with continuous distance and linear combination in the spatial distance table, exclude the spatial break monitoring points and branch jump monitoring points, and output the coal seam roof continuous connection path group;

[0072] After obtaining the spatial coordinate relationship set, the spatial connection path between all monitoring point pairs needs to be established. First, the coordinate difference value of all point pairs is calculated, for example, point C is (10.0 meters, 30.0 meters), point D is (13.0 meters, 33.0 meters), the lateral difference is 3.0 meters, the longitudinal difference is 3.0 meters, and the total distance can be considered as 6.0 meters. If such distance exceeds the preset threshold (such as 3.5 meters), it is considered that the point pair is discontinuous, and the pair needs to be removed. In the process of step-by-step traversal, if the starting point E can be connected to F, F is connected to G, and the distance of each connection segment is less than the set threshold, for example, E-F is 2.0 meters and F-G is 3.0 meters, the path is preliminarily reserved, and the surrounding points of G are continuously searched. If the distance between a certain jump monitoring point and G is 5.8 meters, it is interrupted due to exceeding the limit, and the path is terminated. At the same time, whether there is a jump arrangement phenomenon in the path is analyzed. If the path point number jumps, such as E→F→J→G, it indicates that the arrangement is irregular, and the missing effective point should also be excluded from the path. Finally, only the path group that meets the distance continuity, no jump and single direction is reserved as the coal seam roof continuous connection path set.

[0073] Direction consistency determination submodule: call the coordinate sequence of the section monitoring point of each path in the coal seam roof continuous connection path group, compare with the set angle interval, screen the path set with stable extension direction, and obtain the break tendency path set;

[0074] In order to screen the direction stability of the path group obtained by path continuity recognition, it is necessary to calculate whether the turning angle between the line segments composed of three continuous points in each path is within the acceptable range. For example, a path is composed of points H (10.0 meters, 10.0 meters), I (12.0 meters, 12.0 meters) and J (14.0 meters, 14.0 meters). The direction from H to I is 45 degrees to the right and up, and the direction from I to J is still 45 degrees, which indicates that the direction of the path does not change. If the angle between K (15.0 meters, 15.0 meters) to L (18.0 meters, 18.0 meters) and L to M (19.0 meters, 23.0 meters) in another path changes greatly, such as from 45 degrees to about 80 degrees, the difference is 35 degrees, which exceeds the set tolerance of 30 degrees, then this path is considered to be unstable in direction. In the path extension direction control, a maximum angle fluctuation range (such as 30 degrees) is set, and all paths with angle change values lower than the range are included in the break tendency path set as the reference path set of the roof break direction.

[0075] Please refer to Figure 2 and Figure 5 , the sequential anomaly recognition module includes:

[0076] Time sequence parameter extraction submodule: call the monitoring point data in the break tendency path set, extract the first occurrence time of the peak value of each monitoring point position rock mass pressure and the starting time of the rock stratum displacement response, form a coal seam roof loading response time sequence pair set;

[0077] The maximum value of the rock mass pressure and the time point when the rock displacement starts to respond are extracted for each monitoring point data in the set of breaking trend path. For example, a monitoring point records a continuously rising pressure value during the continuous monitoring process. When the pressure reaches 12.3 MPa, it no longer continues to rise and then decreases. The peak value appears at the 35th hour in this process. In the displacement data, the earliest displacement response starts at the 38th hour. At this time, the displacement value slowly rises from the original 0 mm to 1.2 mm. Two types of time nodes are recorded in this process, which are the extreme value time of the pressure of the point and the starting time of the displacement response. After similar processing of all monitoring points, the loading response time pair of each monitoring point is formed. For example, five monitoring points in a path each have a pressure peak value appearance time and a displacement response time. The time pair is recorded to form the coal seam roof loading response time sequence pair set.

[0078] Loading sequence construction submodule: According to the time record of each monitoring point in the coal seam roof loading response time sequence pair set, the loading time sequence of the coal seam roof is obtained by comparing the loading time of the upstream and downstream monitoring points in sequence according to the topological structure of the monitoring points.

[0079] The pressure peak value and displacement response time sequence pair of all monitoring points are extracted, and the topological structure relationship of each monitoring point in the breaking trend path is processed. For example, there are five points A, B, C, D and E in a path, arranged from upstream to downstream. If the pressure peak value of B appears at the 30th hour and that of C appears at the 28th hour, it means that the pressure loading occurs downstream first. In this case, the module will continue to compare the time sequence of each adjacent point and record whether the downstream is earlier than the upstream in the sequence. For example, the time of point D is the 36th hour and that of point E is the 35th hour. E is earlier than D, which also belongs to the downstream loading priority phenomenon. By comparing the loading time of all monitoring points in the whole path, the actual loading evolution sequence is generated, and a group of actual loading evolution sequences is constructed according to the topological sequence to record the time evolution of each monitoring point, which is used to judge the abnormal loading process of the roof.

[0080] Reverse section identification submodule: Based on the coal seam roof loading evolution sequence set, the abnormal ordering situation in the loading behavior is identified, the monitoring point combination with the pressure peak value earlier than the upstream monitoring point and the corresponding displacement response delay is screened, and whether the distribution of the monitoring point combination has continuity and aggregation trend is judged to obtain the loading sequence reverse abnormal area.

[0081] According to the judgment of the loading evolution sequence set, the path segment with abnormal loading sequence is identified, and the judgment condition is: if a monitoring point is in the downstream in the structure topology, but its pressure peak time is earlier than that of the upstream monitoring point, and its displacement response is also delayed, for example, the upstream point F appears a pressure peak at the 40th hour, and the displacement starts at the 43rd hour, while the downstream point G reaches a pressure peak at the 38th hour, and the displacement changes until the 46th hour, which indicates that the point combination has reverse abnormal loading sequence; then it is judged whether such abnormality exists in the spatially continuous path point combination, if three or more monitoring points on the path meet the characteristics, and the spatial distance of these points is within the threshold range of normal layout interval, such as the adjacent interval is less than 4 meters, it is considered that the path segment has the aggregation of reverse loading sequence, and finally the path segment is summarized as the abnormal area of reverse loading sequence, which is provided to the upper module for coal seam roof structure abnormality early warning.

[0082] Please refer to Figure 2 and Figure 6 , the caving trend monitoring module comprises:

[0083] The extended structure construction submodule calls the spatial coordinates of the abnormal monitoring points in the reverse abnormal loading sequence area, establishes the connection relationship between the adjacent monitoring points according to the arrangement order, and forms the extended vector set of the coal seam roof abnormal section;

[0084] The spatial coordinate information of all the abnormal monitoring points identified in the reverse abnormal loading sequence area is called, and the connection relationship between the adjacent points is established according to the arrangement order of the points in the topological relationship, and a vector set for describing the extension direction of the abnormal path is formed. For example, if the five monitoring points numbered P1 to P5 are included in the abnormal area, and the layout coordinates are the point set extending to the north direction in turn, a vector connection can be established from the first point P1 to P2, and then P2 to P3, P3 to P4, P4 to P5 in turn. Each connection relationship can be represented as an extended vector. In the connection process, it is necessary to check whether there is a layout interval abnormality, such as the horizontal distance between P2 and P3 is 2.5 meters, the vertical distance is 3.0 meters, and the total interval is 5.5 meters. If the value does not exceed the maximum reasonable interval set by the layout (for example, 6.0 meters), the connection relationship is considered valid. Otherwise, the current segment needs to be skipped to build the path. Finally, all the valid connection segments are sorted and summarized to construct the complete coal seam roof abnormal section extension vector set, which is used to describe the propagation trajectory and direction chain of the abnormal area in space.

[0085] The direction feature extraction submodule calculates the angle change of the adjacent vector pairs in the coal seam roof abnormal section extension vector set and judges the direction deviation degree, counts the unit area density of the abnormal monitoring points in the area corresponding to the extension path, and generates the coal seam roof abnormal distribution direction index group.

[0086] The trend stability of the abnormal extension path of the coal seam roof is analyzed, two included angles formed by three continuous vectors in the path are calculated, and the change degree of the included angles is further analyzed to determine whether the direction of the path is suddenly changed. The difference formula of the included angles is used for calculation in this module, and every four continuous monitoring points in the path, such as A, B, C and D, are processed, and three vectors corresponding to A→B, B→C and C→D are formed.

[0087] The calculation formula is:

[0088]

[0089] Wherein, Δθ: represents the change amount of the included angle, the unit is degree (°) or radian (rad), and is used to determine whether the direction of the path is suddenly changed; Vector 1 represents the spatial direction change from monitoring point A to B; Vector 2 represents the spatial direction change from B to C; Vector 3 represents the spatial direction change from C to D; The length of each vector is represented by the length of its geometry, and the calculation method is to square the coordinate components and then take the square root of the sum; arccos(): inverse cosine function, used to calculate the included angle according to the cosine value; the two arccos() expressions correspond to the former included angle (vector 1 and vector 2) and the latter included angle (vector 2 and vector 3) respectively.

[0090] If the monitoring point coordinates are set as follows: A: 10.0 meters in horizontal direction and 10.0 meters in vertical direction; B: 13.0 meters in horizontal direction and 14.0 meters in vertical direction; C: 17.0 meters in horizontal direction and 15.0 meters in vertical direction; D: 20.0 meters in horizontal direction and 13.0 meters in vertical direction.

[0091] Construct vectors:

[0092]

[0093] Calculate the included angle θ1 between and :

[0094] Dot product: 3.0*4.0+4.0*1.0=16.0;

[0095] Length:

[0096] Included angle:

[0097] Calculate the included angle θ2 between and :

[0098] Dot product: 4.0 * 3.0 + 1.0 * (-2.0) = 10;

[0099] Module length:

[0100] Angle:

[0101] Calculate the angle change: Δθ = | 47.2° - 39.1° | = 8.1°.

[0102] This result indicates that the direction is deflected by about 8.1 degrees between the path B→C→D, and if the system sets the angle fluctuation threshold to be stable within 10 degrees, then the path direction in this section is stable.

[0103] The same calculation is performed for all consecutive four points on each path, and the number of segments or the ratio of segments with an angle change exceeding the set threshold (such as 10 degrees) is counted. At the same time, the abnormal monitoring point density in the corresponding area is counted, for example, if the path covers an area of 15 square meters and the number of monitoring points is 12, then the unit area density is 12 ÷ 15 = 0.8 points / square meter. Finally, all the angle change values and spatial density values together form the coal seam roof abnormal distribution direction index group, which is called by the trend result generation submodule for judging the consistency and concentration of the overall extension direction.

[0104] Trend result generation submodule: combine the angle change characteristics and spatial density data in the coal seam roof abnormal distribution direction index group to uniformly determine the consistency and concentration performance of the extension trend in each area, and obtain the coal seam roof regional collapse trend monitoring result;

[0105] On the basis of the direction index construction, integrate the information in the coal seam roof abnormal distribution direction index group to form the judgment result of the regional breakage trend. In specific processing, first extract the calculated angle change values in each abnormal path, and judge whether these angle changes are stable within a unified direction range, for example, if all the angle changes in a path are less than 10 degrees, the system can consider that the path direction shows consistency; then count the abnormal monitoring point distribution density of the space area covered by the path, and if the density is greater than the preset threshold, such as 0.7 points / square meter, the system considers that the abnormal phenomenon is concentratedly distributed. Then divide the entire monitoring area into multiple sub-areas, such as 25 square meters for each grid unit, and count whether the path direction is concentrated and consistent and whether the abnormal point distribution is dense in each grid. If there are more than three abnormal paths with an extension direction change less than 10 degrees in the grid, and the monitoring point density reaches or exceeds 0.8 points / square meter, then the area is uniformly determined as a region with consistent and concentrated breakage trend.

[0106] See Figure 2 and Figure 7Further comprising a stability level evaluation module: according to the coal seam roof region collapse trend monitoring result, the risk level of the coal seam roof region collapse is divided, and the coal seam roof region stability evaluation result is obtained;

[0107] The coal seam roof region stability evaluation result includes a risk level category, an evaluation reference, and a warning level state.

[0108] The stability level evaluation module comprises:

[0109] A trend index calling submodule: based on the coal seam roof region collapse trend monitoring result, the angle change range in each monitoring region and the number of abnormal monitoring points in a specified area are extracted, and a coal seam roof trend judgment index group is established.

[0110] After completing the region division of the collapse trend monitoring result, the trend index in each independent monitoring region is extracted, mainly including two aspects: one is to count the angle change range of all the extension paths in the region, and the other is to count the number of abnormal monitoring points in a specified unit area. When processing the angle change, the system will statistically process all the angle change values of each path in the region, for example, in a 30 square meter region, there are 5 abnormal paths, and the maximum angle change in each path is recorded. The final maximum angle change range of the region is 13 to 28 degrees. At the same time, the system calculates the density of abnormal monitoring points in the region, for example, 24 abnormal points are recorded, and the area is 30 square meters, so the density is 0.8 points per square meter. The system encapsulates the maximum angle change range and the abnormal point density of each region as a trend index unit, and a trend judgment index group is formed after the aggregation of multiple units. The angle change index is mainly used to judge whether the path direction is stable, and the density index is used to measure the abnormal aggregation degree, wherein the angle change demarcation standard is set to be consistent within 20 degrees, general between 20 and 40 degrees, and discrete more than 40 degrees; the density standard is set to be sparse below 0.5 points per square meter, medium between 0.5 and 0.8, and dense more than 0.8, and all the demarcation values are established based on the average value and standard deviation of the statistical samples in the historical stability evaluation report.

[0111] A level rule matching submodule: according to the coal seam roof trend judgment index group, combined with the stability evaluation parameters set in the current period, the relationship between the two is compared according to the level boundary standard, and a coal seam roof trend level division label set is output.

[0112] The data in the coal seam roof trend determination index group are compared with the stability level evaluation standard set in the current period, and each rule matching process takes specific quantitative indicators as the basis. The system one-to-one corresponds the angle change range and abnormal point density of all regions with the level standard, for example, setting the first level stable state to meet the angle change less than 15 degrees and the density less than 0.4 points per square meter, the second level state to meet the angle change between 15 to 30 degrees and the density between 0.4 to 0.7, and the third level state to be greater than 30 degrees or the density greater than 0.7 points per square meter. The system calls the matching logic module for each region to compare rules, for example, the maximum angle of a certain region is 27 degrees, and the point density is 0.85 points per square meter, the system judges that although the angle meets the second level standard, the density has exceeded the upper limit, and needs to be raised to the third level, finally the region is marked as the third level trend level, and is added to the coal seam roof trend level division label set. All level standards come from the experience statistical analysis of the roof breakage behavior, and three level interval boundaries are defined according to the collection of historical typical cases and the definition of engineering feedback data.

[0113] The evaluation result generation submodule: based on the coal seam roof trend level division label set, the level determination total table of the current period is constructed, and the coal seam roof regional stability evaluation result is obtained;

[0114] According to the coal seam roof trend level division label set, the stability level determination total table of the current monitoring period is summarized and constructed, in the processing flow, the system will retrieve the level label corresponding to each monitoring region one by one, and write the region number, maximum angle change value, unit area point density, level level value and other fields in the output table. For example, the maximum angle of a certain region is 32 degrees, the density is 0.9 points per square meter, and the corresponding level is the third level, which is listed in numerical form in the table, and the level distribution of all regions is summarized. If the system statistics that the third level region accounts for more than 30%, the evaluation result of the period will be marked as there is a widespread breakage trend; if the first level region accounts for more than 60%, the system outputs the stability trend determination. The system makes the final stability evaluation through the dual judgment of level proportion and absolute number, and all results are written into the period stability evaluation record file and synchronized to the engineering monitoring end for display. The judgment ratio threshold is set according to the average level of the proportion of each level region in the last 20 periods to ensure that the evaluation standard has engineering adaptability and stability.

[0115] The above is only a preferred embodiment of the present application, and does not limit the present application in other forms. Any skilled person in the art can modify or change the above disclosed technical content to equivalent embodiments applied to other fields, but any simple modification, equivalent change and modification made according to the technical essence of the present application to the above embodiments still belongs to the protection scope of the technical solution of the present application.

Claims

1. A coal seam roof pressure monitoring and analysis system, characterized by: The system comprises: Stress anomaly identification module: obtains rock pressure data and rock displacement data in the coal seam roof boundary area, identifies the changing trend of rock pressure response at the coal seam roof boundary position, and marks the monitoring point set of boundary stress asymmetry trend; Trend path construction module: performs path continuity identification on the boundary stress asymmetric trend monitoring point set, determines the breaking trend in the path extension direction, and constructs a breaking trend path set; Sequence anomaly identification module: Analyzes the loading evolution sequence of the coal seam roof strata based on the fracture trend path set and identifies the loading sequence reversal abnormal area in the coal seam roof structure; Collapse trend monitoring module: obtains the distribution pattern of the abnormal area where the loading sequence is reversed, extracts the change characteristics of the extension direction of the abnormal area, and obtains the collapse trend monitoring results of the coal seam roof area.

2. The coal seam roof pressure monitoring and analysis system according to claim 1, characterized in that: The boundary stress asymmetric trend monitoring point set includes monitoring point distribution information, pressure response direction, and displacement response amplitude; the fracture trend path set includes path direction information, path extension length, and a continuous monitoring point column; the loading sequence reversal abnormal area includes loading sequence arrangement, peak response time difference, and delayed response distribution; the coal seam roof area collapse trend monitoring results include trend direction changes, abnormal section morphology, and periodic evolution trends.

3. The coal seam roof pressure monitoring and analysis system according to claim 1, characterized in that: The stress anomaly identification module includes: Monitoring data acquisition submodule: obtains the rock mass pressure time series data and rock formation displacement change rate data of each distributed monitoring point in the coal seam roof monitoring area in the current period, and obtains the coal seam roof monitoring period data set; Boundary monitoring point identification submodule: Based on the layout coordinates of the monitoring points in the coal seam roof synchronous monitoring data set, the monitoring points at the outer geometric edge are identified to form a boundary monitoring point set, and the horizontal and vertical monitoring point pairs are constructed based on the spatial layout between adjacent monitoring points to form a coal seam roof boundary pressure difference sequence; Trend anomaly extraction submodule: Based on the coal seam roof boundary pressure difference sequence and the rock stratum displacement change rate of the internal monitoring point adjacent to the boundary monitoring point, the cumulative sum control chart algorithm is called to identify the mutation trend of the difference sequence. If the pressure response direction is consistent and the displacement change rate direction is the same and shows a mutation, the corresponding area is marked as an abnormal monitoring point, and the boundary stress asymmetric trend monitoring point set is obtained.

4. The coal seam roof pressure monitoring and analysis system according to claim 3, characterized in that: Identify the mutation trend of the difference sequence using the formula: S k =max(0,S k-1 +(x k -μ-K')); Calculate the CUSUM cumulative statistics S under the kth monitoring period k , if S k If it is continuously equal to 0, it means that there is no significant deviation between the current data and the historical status, and the trend is stable. k If a positive value appears, it means that the pressure difference of the current cycle has exceeded the tolerance range and abnormalities have begun to accumulate. If the next S k If it continues to increase, it means that the abnormal trend is continuing, constituting a mutation trend; Among them, S k-1 is the cumulative statistic of the CUSUM in the previous k-1 period, x k is the pressure difference between the boundary monitoring points of the kth period, μ is the process target value, K' is the reference value, and max(0,) is used to prevent negative accumulation so that the CUSUM value returns to 0 when there is no mutation.

5. The coal seam roof pressure monitoring and analysis system according to claim 1, characterized in that: The trend path building module includes: Spatial coordinate extraction submodule: obtains the spatial position of the boundary stress asymmetric trend monitoring point set, analyzes the distribution coordinates of each monitoring point in the monitoring area coordinate system, extracts the coordinate relationship between the monitoring point pairs, and establishes the coal seam roof trend monitoring point spatial relationship set based on the coordinate spacing relationship; Path continuity identification submodule: constructs a spatial distance table between all pairs of monitoring points based on the spatial relationship set of the coal seam roof trend monitoring points, identifies connection sequences in the spatial distance table that are continuous and form linear combinations, excludes spatially discontinuous monitoring points and branch jump monitoring points, and outputs a coal seam roof continuous connection path group; Direction consistency determination submodule: calls the node monitoring point coordinate sequence of each path in the coal seam roof continuous connection path group, compares it with the set angle interval, screens the path set with stable extension direction, and obtains the breaking trend path set.

6. The coal seam roof pressure monitoring and analysis system according to claim 1, characterized in that: The sequence anomaly identification module includes: The time series parameter extraction submodule calls the monitoring point data in the fracture trend path set, extracts the first occurrence time of the rock mass pressure peak and the starting time of the rock formation displacement response at each monitoring point, and forms a coal seam roof loading response time series pair set; Loading sequence construction submodule: Based on the time record of each monitoring point in the coal seam roof loading response time sequence, combined with the topological structure order of the monitoring points, the loading time sequence relationship between the upstream and downstream monitoring points is compared in sequence to obtain the coal seam roof loading evolution sequence set; Reversal section identification submodule: Based on the coal seam roof loading evolution sequence set, it identifies abnormal sorting in the loading behavior, screens the monitoring point combinations whose pressure peak is earlier than the upstream monitoring point of the structure and whose corresponding displacement response is delayed, and determines whether the distribution of the monitoring point combination has continuity and aggregation trends, thereby obtaining the abnormal area of ​​loading sequence reversal.

7. The coal seam roof pressure monitoring and analysis system according to claim 1, characterized in that: The collapse trend monitoring module includes: Extension structure construction submodule: calling the loading sequence to reverse the spatial coordinates of abnormal monitoring points in the abnormal area, establishing a connection relationship between adjacent monitoring points according to the arrangement order, and forming an extension vector set of the abnormal section of the coal seam roof; Directional feature extraction submodule: Based on the adjacent vector pairs in the extended vector set of the coal seam roof abnormal section, the angle change of the adjacent vector pairs is calculated and the degree of directional deviation is determined. The unit area density of abnormal monitoring points in the area corresponding to the extended path is counted to generate a coal seam roof abnormal distribution direction index group; Trend result generation submodule: Combining the angle change characteristics and spatial density data in the coal seam roof abnormal distribution direction indicator group, uniformly determine the consistency and concentration of the extension trend of each area, and obtain the coal seam roof area collapse trend monitoring results.

8. The coal seam roof pressure monitoring and analysis system according to claim 7, characterized in that: Calculate the angle change Δθ between adjacent vector pairs using the formula: in, Indicates the change in spatial direction from monitoring point A to monitoring point B, Indicates the change in spatial direction from monitoring point B to monitoring point C, Indicates the change in spatial direction from monitoring point C to monitoring point D.

9. The coal seam roof pressure monitoring and analysis system according to claim 1, characterized in that: The invention also includes a stability level assessment module: according to the coal seam roof area collapse trend monitoring result, the risk level of the coal seam roof area collapse is divided to obtain the coal seam roof area stability assessment result; The coal seam roof area stability assessment results include risk level category, assessment reference basis, and warning level status.

10. The coal seam roof pressure monitoring and analysis system according to claim 9, characterized in that: The stability level assessment module includes: Trend indicator calling submodule: Based on the coal seam roof area collapse trend monitoring results, the angle variation range in each monitoring area and the number of abnormal monitoring points within the specified area are extracted to establish a coal seam roof trend determination indicator group; Grade rule matching submodule: Based on the coal seam roof trend determination index group and the stability assessment parameters set in the current period, the relationship between the two is compared according to the grade boundary standard, and a coal seam roof trend grade classification label set is output; Evaluation result generation submodule: Based on the coal seam roof trend grade classification label set, a grade determination summary table for the current period is constructed to obtain the coal seam roof regional stability evaluation result.

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