Roof stability monitoring and control method based on hydraulic support

Abstract

The present invention relates to the technical field of coal mine equipment, and specifically to a roof stability monitoring and control and coal wall weakening method based on a hydraulic support. By constructing a roof stability monitoring and early warning model, the working face roof condition is monitored by a hydraulic support, and the hydraulic support is dynamically adjusted based on roof feature recognition and dynamic zoning to improve the crushing effect of thick hard coal seams, predict the roof condition in the working face advancement direction, change the hydraulic support pressure regulation strategy in real time, and eliminate the lag in the adjustment and adaptation of the existing pressure regulation strategy.

Description

Technical field:

[0001] The present invention relates to the technical field of coal mine equipment, and in particular to a roof stability monitoring and control method based on a hydraulic support. Background technology:

[0002] The existing underground mining for thick coal seams generally adopts the top coal caving technology. However, when the coal wall is thick and hard, the top coal caving ability will be poor, resulting in slow coal cutting speed of the coal shearer and large wear of the pick. At the same time, the mined coal blocks are large, which are easy to block the coal passing space under the coal shearer. In addition, the coal wall in the advancing direction is easy to accumulate elastic potential energy, resulting in risks such as explosion or coal mine explosion. The top coal is not easy to collapse, resulting in a large amount of coal loss during mining. The existing creep yielding technology is used for thick and hard coal walls. The support strategy of hydraulic supports is to bear pressure and yield pressure at intervals to accelerate the sinking of the working face roof. The coal seam in the advancing direction is broken by the sinking pressure of the roof, reducing the thickness and hardness of the coal wall, making the top coal easy to collapse.

[0003] However, when creep pressure relief is adopted, the hydraulic support pressure or pressure relief strategy is adjusted slowly, and there is a lag in the adjustment and adaptation to special roof conditions. In the roof sinking and pressure zone, when the pressure relief support fails to adjust the pressure in time, the pressure support will be over-pressured, resulting in damage or failure, or even the risk of roof collapse. At the same time, in the roof crushing zone, the pressure support may not be connected in time, resulting in the column extending too high, while the adjacent pressure relief support is in a lower column state, resulting in abnormal overlap of adjacent supports. Since the pressure adjustment strategy is too slow, the expected effect is often not achieved for harder coal seams. In the mining process, large roof beams in the mined area behind the working face may not collapse, and when they collapse, they will cause a strong impact pressure accident. Therefore, it is necessary to develop a roof stability monitoring and control and coal wall weakening method based on hydraulic supports. Summary of the invention:

[0004] In response to the above-mentioned defects and problems, the present invention provides a roof stability monitoring and control and coal wall weakening method based on hydraulic supports, the purpose of which is to construct a roof stability monitoring and early warning model, monitor the working face roof conditions through hydraulic supports, and enable the hydraulic supports to dynamically adjust the pressure regulation strategy based on roof feature recognition and dynamic zoning, thereby improving the crushing effect of thick hard coal seams, predicting the roof conditions in the working face advancement direction, changing the pressure regulation strategy of the hydraulic supports in real time, and eliminating the lag in the adjustment and adaptation of existing pressure regulation strategies.

[0005] The present invention solves the technical problem by adopting a method for monitoring and controlling roof stability and weakening coal walls based on a hydraulic support. The hydraulic support is equipped with a sensor for monitoring bearing pressure, a sensor for monitoring support angle inclination, and a sensor for monitoring propulsion stroke. It is also equipped with a pressure limiting component, a control component, and a data transmission component. A roof stability monitoring and early warning model is also established.

[0006] S1. Identification and judgment of hydraulic support top plate features:

[0007] 1) Based on the pressure data of the hydraulic support monitored by the sensor, determine whether the roof working surface is in the roof sinking pressure area, identify the location of the roof sinking pressure area and determine the pressure intensity:

[0008] 2) Based on the mine pressure data, identify the areas with high-pressure hydraulic supports within the range, determine the pressure-bearing conditions, resistance increase conditions and high-pressure duration of the hydraulic supports in these areas, and determine whether they belong to the roof subsidence pressure area. For the identified roof subsidence pressure area, record and analyze the area size and resistance increase pressure degree;

[0009] 3) Based on the hydraulic support pressure data monitored by the sensor, determine whether the roof working surface is in the roof crushing zone, and identify the location and degree of crushing of the roof crushing zone:

[0010] 4) Based on the mine pressure data, identify the areas with concentrated low-pressure hydraulic supports within the range, determine the pressure bearing conditions, resistance increase conditions and low-pressure duration of the hydraulic supports in these areas, eliminate the causes of the hydraulic support's own failures based on the actual working condition data of the hydraulic supports, and determine whether it belongs to the roof crushing area. For the identified roof crushing area, record and analyze the area size and crushing degree;

[0011] S2. Hydraulic support posture recognition and judgment:

[0012] 1) Based on the inclination and posture data of each part of the hydraulic support monitored by the sensor, determine whether the hydraulic support has any abnormal posture;

[0013] 2) Based on the difference in pitch angles between the top beam and base of the hydraulic support, determine whether the hydraulic support is in an abnormal posture where the top beam elevation angle is too large or too small. Based on the difference in the roll angle of the hydraulic support base and the corresponding angle data of the working surface or coal mining machine, determine whether the hydraulic support is tilted or at risk of tipping over.

[0014] 3) Based on the posture data of the hydraulic supports on the working surface monitored by sensors, it is determined whether there are adjacent hydraulic supports in an abnormal overlapping state;

[0015] 4) Based on the mining height data of adjacent hydraulic supports monitored by sensors, determine whether the hydraulic supports are too high or too low, resulting in gaps in the hydraulic support support for gangue to pass through; based on the pitch angle data of the top beams of adjacent hydraulic supports monitored by sensors, determine whether the top beams of the hydraulic supports are greatly offset, resulting in support holes at the head or tail of the top beams; based on the roll angle data of the bases of adjacent hydraulic supports monitored by sensors, determine whether the top beams of adjacent hydraulic supports will be squeezed and collided or have support holes;

[0016] S3. Determination of the point of action of the resultant force on the roof:

[0017] 1) Based on the hydraulic support posture data and pressure data monitored by the sensor, determine the position of the resultant force acting point of the top plate on the hydraulic support at the top beam, and calculate and determine the position of the resultant force acting point based on the top beam pressure data;

[0018] S4. Special roof feature warning:

[0019] 1) Based on the pressure data, posture data and the position of the resultant force point of the hydraulic support monitored by the sensor, the roof characteristics in front of the hydraulic support are predicted and analyzed. When special roof characteristics are analyzed, an early warning is issued to the corresponding area of ​​the working surface;

[0020] S5. Dynamic zoning of roof stability: Based on the working face roof feature monitoring data and prediction analysis results, a working face roof stability model is constructed. Dynamic zoning is performed based on roof stability, dividing it into roof stability zone, rotation acceleration zone, and instability risk zone. Based on the results of dynamic zoning of roof stability, different hydraulic support pressure regulation strategies are implemented for different areas.

[0021] S6. Pressure and attitude control of single hydraulic support: The pressure-bearing intensity sensor on the hydraulic support monitors the roof pressure and distribution in real time, and the attitude of the support is fed back through the sensor monitoring the angle and inclination of the support. The single hydraulic support is controlled by the control component, the output of each jack of the hydraulic support is adjusted, the spatial position of each part of the hydraulic support is controlled, and the pressure of the hydraulic support is adjusted by the top-wiping frame shifting safety valve. The hydraulic support is regulated according to the different roof stability targets, so that the hydraulic support can achieve creep pressure relief, fluid replenishment pressure relief, column lowering pressure relief and top beam attitude adjustment, and the pressure of the hydraulic support is controlled. The data transmission component can transmit the data monitored by each sensor to the host computer, and the attitude and pressure adjustment of the hydraulic support can be remotely controlled by the controller.

[0022] Furthermore, the criteria for determining the dynamic partitioning of roof stability in S5 are as follows:

[0023] 1) Roof stability zone: ① There is no roof sinking pressure zone or roof crushing zone in the area; ② There is no special roof area warning in the area; ③ There is no abnormal posture of hydraulic support in the area; ④ The combined force action point of the hydraulic support is in the middle of the roof beam;

[0024] 2) Rotation acceleration zone: ① There are no roof sinking pressure areas or roof crushing areas in the area; ② There are no special roof area warnings in the area, or there are low-risk warnings; ③ There are no abnormal hydraulic support postures in the area, or there are abnormal roof beam pitch angles; ④ The hydraulic support force action point is offset toward the front of the roof beam;

[0025] 3) Instability risk areas: ① There may be roof sinking pressure areas and roof crushing areas in the area, ② There are high-risk warnings for special roof areas in the area, ③ There are abnormal hydraulic support overlaps and abnormal pitch angles in the area, ④ The combined force application point of the hydraulic support is at the front or rear of the top beam.

[0026] Furthermore, different hydraulic support pressure regulation strategies are implemented in different areas: for the roof stable area, the pressure regulation strategy is creep pressure relief, 2-3 pressure relief supports are arranged between the pressure-bearing hydraulic supports, the initial support force and working resistance of the pressure relief supports are configured to be small, and the pressure relief supports use top-wiping frame moving safety valves to control flow and pressure relief, so that the column will not be quickly lowered during the pressure relief process, and the overlap with the adjacent supports is normal;

[0027] Rotation acceleration zone: The pressure regulation strategy is creep pressure relief. 0-1 pressure relief supports are arranged at intervals between the pressure-bearing hydraulic supports. The initial support force and working resistance of the pressure relief supports are greater than those in the roof stability zone. The pressure relief supports use a top-rubbing frame moving safety valve to control the flow and pressure relief, so that the column does not drop during the pressure relief process and the overlap with the adjacent supports is normal. If there are hydraulic supports with abnormal postures, they will be adjusted in real time to normal support;

[0028] Instability risk area: The pressure regulation strategy is to add fluid to bear pressure. All hydraulic supports are pressure-bearing supports, and no pressure-yielding supports are configured. According to the predicted data of the top plate stability, the posture of the hydraulic support is dynamically adjusted, and the top-wiping and frame-shifting safety valve is used to ensure the support continuity and stability of the hydraulic support.

[0029] Furthermore, the sensors for monitoring the bearing pressure include a column pressure sensor, a balancing jack pressure sensor and a top beam pressure grating sensor; the sensors for monitoring the angle of inclination of the support include a base inclination sensor, a connecting rod inclination sensor, a top beam inclination sensor and a guard plate inclination sensor; the sensors for monitoring the propulsion stroke include an infrared receiver and a displacement sensor; the pressure limiting component includes a top-wiping frame safety valve, which can control the hydraulic support to slowly release pressure at a small flow rate and quickly release pressure at a large flow rate, to erect or lower the hydraulic support column; the control component includes a controller, which controls the solenoid valve driver, and the solenoid valve driver controls the electro-hydraulic reversing valve group on the hydraulic support to control the action of the hydraulic support; the data transmission component includes a controller cable and a sensor cable.

[0030] Furthermore, the roof stability monitoring uses a neural network to adaptively judge the pressure characteristics in front of the roof sinking pressure area or the roof crushing area, and issues corresponding early warning signals based on the judged characteristics.

[0031] Beneficial effects of the present invention: The present invention monitors the stability of the roof based on the monitoring data of each sensor set on the hydraulic support, establishes a stability monitoring and early warning model, dynamically partitions the stability of the roof of the working face, and accurately judges the roof situation through the stability monitoring and early warning model to ensure that the working face uses a suitable hydraulic support pressure regulation strategy, and judges the situation of the roof in front of the working face in advance, pre-adjusts the hydraulic support pressure regulation strategy, adopts different support strategies for different areas of the working face, ensures support strength and accelerates the rotation and sinking of the roof and the crushing of the coal seam, and when the hydraulic support moves forward, it can use different frame moving strategies according to the roof situation to ensure support strength; for the posture monitoring of the hydraulic support, when the posture of the hydraulic support is abnormal, it can be adjusted in time, and based on the abnormal situation of the support posture, its pressure regulation strategy can be adjusted to fit the underground working conditions, achieve stable support and ensure creep pressure relief effect. Description of the drawings:

[0032] Figure 1 This is the force diagram of the two-column top-supported shield support.

[0033] Figure 2 Schematic diagram of roof collapse.

[0034] Figure 3 Schematic diagram of the top plate feature zoning.

[0035] Figure 4 This is a control model diagram for a single hydraulic support. Specific implementation method:

[0036] The present invention will be further described below with reference to the accompanying drawings and examples.

[0037] In the embodiment 1, when creep pressure relief is adopted, the hydraulic support pressure bearing or pressure relief strategy is adjusted slowly, and there is a lag in the adjustment and adaptation to special roof conditions. In the roof sinking and pressure zone, if the pressure relief support fails to adjust the pressure in time, the pressure bearing support will be too high, resulting in damage or failure, and even the risk of roof collapse. At the same time, in the roof fracture zone, the pressure bearing support may not be connected in time, resulting in the column extending too high, while the adjacent pressure relief support is in a lower column state, resulting in abnormal overlap of adjacent supports. Since the pressure adjustment strategy is too slow, the expected effect is often not achieved for harder coal seams. In addition, during the mining process, large roof beams in the mined area behind the working face may not collapse, and when they collapse, a strong impact pressure accident may be caused. In view of the slow adjustment and adaptation lag of the existing hydraulic support pressure adjustment strategy, this embodiment provides a roof stability monitoring and control and coal wall weakening method based on a hydraulic support. A sensor for monitoring the bearing pressure, a sensor for monitoring the support angle inclination, and a sensor for monitoring the propulsion stroke are provided on the hydraulic support.

[0038] The sensors for monitoring the bearing pressure include the column pressure sensor (detecting the bearing pressure of the hydraulic support column cylinder), the balance jack pressure sensor (detecting the bearing pressure of the front and rear cylinders of the hydraulic support balance jack) and the top beam pressure grating sensor (detecting the bearing pressure at each position of the hydraulic support top beam);

[0039] The sensors for monitoring the tilt angle of the support include the base tilt sensor (detecting the roll angle and pitch angle of the hydraulic support base), the connecting rod tilt sensor (detecting the roll angle and pitch angle of the hydraulic support connecting rod), the top beam tilt sensor (detecting the roll angle and pitch angle of the hydraulic support top beam) and the guard plate tilt sensor (detecting the roll angle and pitch angle of the hydraulic support guard plate).

[0040] The sensors for monitoring the propulsion stroke include an infrared receiver (which receives infrared rays emitted by the shearer to detect the position of the shearer) and a displacement sensor (which detects the displacement of the push jack). A top-scratching safety valve is provided on the hydraulic support (the top-scratching safety valve adopts existing equipment, and its effect and structure are not described in detail here). This valve can release pressure slowly at a small flow rate or quickly at a large flow rate to achieve the erection or lowering of the column.

[0041] The control component of the hydraulic support includes an electro-hydraulic reversing valve group, which is controlled by a solenoid valve driver to control the movement of the hydraulic support. The data transmission component includes a sensor cable and a controller cable.

[0042] Establish a roof stability monitoring and early warning model:

[0043] S1. Real-time feature recognition and judgment of hydraulic support top plate:

[0044] 1) Based on the pressure data of the hydraulic support monitored by the pressure sensor, determine whether the roof working surface is in the roof sinking pressure area, identify the location of the roof sinking pressure area and determine the pressure intensity:

[0045] 2) Based on the real-time hydraulic support column pressure data of the working face, identify the areas with high-pressure hydraulic supports within the range, determine the pressure bearing conditions, resistance increase conditions and high-pressure duration of the hydraulic supports in these areas, and determine whether they belong to the roof subsidence pressure area. For the identified roof subsidence pressure area, record and analyze the area size and resistance increase pressure degree;

[0046] When there are many continuous hydraulic supports (more than 10-20 supports) with a bearing pressure close to or exceeding the rated working pressure of the working face, it is determined to be a possible roof sinking pressure area. The historical pressure data of the hydraulic supports in the above area are queried to detect whether there is a fast increase in support resistance, an increase in support pressure with advancement, and the opening of the safety valve. The posture of the hydraulic supports in the area is determined, and whether there is a feature of low support height. The position of the hydraulic support resultant force action point is detected to see if it is biased towards the front end of the top beam. If the above corresponding features exist, the target area is determined to be a roof sinking pressure area.

[0047] 3) Based on the hydraulic support pressure data monitored by the sensor, determine whether the roof working surface is in the roof crushing zone, and identify the location and degree of crushing of the roof crushing zone:

[0048] 4) Based on the real-time hydraulic support column pressure data of the working face, identify the hydraulic support dense areas with low pressure within the range, determine the pressure bearing conditions, resistance increase conditions and low pressure duration of the hydraulic support in these areas, eliminate the cause of the hydraulic support failure based on the actual working condition data of the hydraulic support, and determine whether it belongs to the roof crushing area. For the identified roof crushing area, record and analyze the area size and crushing degree;

[0049] When there are a certain number of continuous hydraulic supports (more than 4-6 supports) with pressure lower than the rated initial support force, it is determined to be a possible roof crushing area. The historical pressure data of the hydraulic supports in the above area are queried to detect whether there is a feature that the initial support force and support pressure gradually decrease with advancement. The posture of the hydraulic supports in the area is determined to detect whether there are abnormal overlaps and excessive support heights. If the above corresponding features exist, the target area is determined to be a roof crushing area.

[0050] S2. Hydraulic support posture recognition and judgment:

[0051] 1) Based on the inclination and posture data of each part of the hydraulic support monitored by the sensor, determine whether the hydraulic support has any abnormal posture;

[0052] 2) Based on the difference in pitch angles between the top beam and base of the hydraulic support, determine whether the hydraulic support is in an abnormal posture where the top beam elevation angle is too large or too small. Based on the difference in the roll angle of the hydraulic support base and the corresponding angle data of the working surface or coal mining machine, determine whether the hydraulic support is tilted or at risk of tipping over.

[0053] 3) Based on the posture data of the hydraulic supports on the working surface monitored by sensors, it is determined whether there are adjacent hydraulic supports in an abnormal overlapping state;

[0054] 4) Based on the mining height data of adjacent hydraulic supports monitored by sensors, determine whether the hydraulic supports are too high or too low, resulting in gaps in the hydraulic support support for gangue to pass through; based on the pitch angle data of the top beams of adjacent hydraulic supports monitored by sensors, determine whether the top beams of the hydraulic supports are greatly offset, resulting in support holes at the head or tail of the top beams; based on the roll angle data of the bases of adjacent hydraulic supports monitored by sensors, determine whether the top beams of adjacent hydraulic supports will be squeezed and collided or have support holes;

[0055] S3. Determination of the point of action of the resultant force on the roof:

[0056] This embodiment is described with respect to a two-column top-supporting shielding bracket. Figure 1 As shown,

[0057] Take the top beam and the shield beam as isolated bodies, and the moment balance equation of each force on point O1 is:

[0058]

[0059] The force balance equations of each force on the horizontal and vertical axes are:

[0060] Qf+F1sinα1+F2sinα2–Psinβ=0(1-2)

[0061] Pcosβ+F1cosα1+F2cosα2–Q=0(1-3)

[0062] Then take the top beam as the isolated body, and the moment balance equation of each force about point O is:

[0063] tP E +Pr2+QfH0–xQ=0(1-4)

[0064] Solving equations (1-1) and (1-4), the vertical support force of the bracket is:

[0065]

[0066] Position of the top beam resultant force action point:

[0067]

[0068] Solving equations (1-2) and (1-3), the front and rear connecting rod forces are:

[0069]

[0070] In the formula

[0071] f——Friction coefficient between top beam and top plate, generally f=0~0.3;

[0072] P——column working resistance;

[0073] P E - Balance the jack force;

[0074] ——As shown in the figure;

[0075] 1) Based on the hydraulic support posture data and pressure data monitored by the sensor, determine the position of the resultant force acting point of the top plate on the hydraulic support at the top beam, and calculate and determine the position of the resultant force acting point based on the top beam pressure data;

[0076] S4. Special roof feature warning:

[0077] 1) Based on the pressure data, posture data and the position of the resultant force point of the hydraulic support monitored by the sensor, the roof characteristics in front of the hydraulic support are predicted and analyzed. When special roof characteristics (roof sinking pressure area or roof crushing area) are analyzed, an early warning is issued to the corresponding area of ​​the working surface;

[0078] S5. Dynamic zoning of top plate stability:

[0079] Based on the monitoring data and prediction analysis results of the working face roof characteristics, a working face roof stability model is constructed. Dynamic zoning is performed based on the roof stability, which is divided into roof stability zone, rotation acceleration zone, and instability risk zone. The criteria for determining the dynamic zoning of roof stability are:

[0080] 1) Roof stability zone: ① There is no roof sinking pressure zone or roof crushing zone in the area; ② There is no special roof area warning in the area; ③ There is no abnormal posture of hydraulic support in the area; ④ The combined force action point of the hydraulic support is in the middle of the roof beam;

[0081] 2) Rotation acceleration zone: ① There are no roof sinking pressure areas or roof crushing areas in the area; ② There are no special roof area warnings in the area, or there are low-risk warnings; ③ There are no abnormal hydraulic support postures in the area, or there are abnormal roof beam pitch angles; ④ The hydraulic support force action point is offset toward the front of the roof beam;

[0082] 3) Instability risk areas: ① There may be roof sinking pressure areas and roof crushing areas in the area, ② There are high-risk warnings for special roof areas in the area, ③ There are abnormal hydraulic support overlaps and abnormal pitch angles in the area, ④ The combined force application point of the hydraulic support is at the front or rear of the top beam.

[0083] Based on the results of dynamic zoning of roof stability, different hydraulic support pressure regulation strategies are implemented for different areas, and the hydraulic support pressure regulation strategies are adjusted in real time according to the changes in zoning conditions:

[0084] In the roof stabilization area, the pressure regulation strategy is creep pressure relief. Two to three pressure relief supports are arranged between the pressure-bearing hydraulic supports. The initial support force and working resistance of the pressure relief supports are relatively small. The pressure relief supports use top-rubbing frame moving safety valves to control flow and pressure relief, so that the columns will not fall quickly during the pressure relief process and the overlap with the adjacent supports is normal.

[0085] Rotation acceleration zone: The pressure regulation strategy is creep pressure relief. 0-1 pressure relief supports are arranged at intervals between the pressure-bearing hydraulic supports. The initial support force and working resistance of the pressure relief supports are configured to be greater than those in the roof stability zone. The pressure relief supports use a top-rubbing frame moving safety valve to control the flow and pressure relief, so that the column does not drop during the pressure relief process and the overlap with the adjacent supports is normal. If there are pressure-bearing hydraulic supports with abnormal postures, they will be adjusted in real time to normal support;

[0086] Instability risk area: The pressure regulation strategy is to add fluid to bear pressure. All hydraulic supports are pressure-bearing supports, and no pressure-yielding supports are configured. According to the predicted data of the top plate stability, the posture of the hydraulic support is dynamically adjusted, and the top-wiping and frame-shifting safety valve is used to ensure the support continuity and stability of the hydraulic support.

[0087] S6. Single hydraulic support pressure and attitude control: The pressure-bearing sensors on the hydraulic support monitor the roof pressure and distribution in real time, and the support attitude is fed back through the sensors that monitor the support angle and inclination. The single hydraulic support is controlled by the control component, the output of each jack of the hydraulic support is adjusted, the spatial position of each part of the hydraulic support is controlled, and the pressure of the hydraulic support is adjusted by the top-wiping frame shifting safety valve. The hydraulic support is regulated according to the different roof stability targets, so that the hydraulic support can achieve creep pressure relief, fluid replenishment pressure relief, column lowering pressure relief and top beam attitude adjustment to control the pressure of the hydraulic support. The data transmission component can transmit the data monitored by each sensor to the upper computer, monitor the pressure, attitude state and height of the hydraulic support in real time, identify and locate possible single-frame attitude anomalies, instability during the frame shifting process, and abnormal areas of multiple-frame attitude groups, provide auxiliary information for remote control of the hydraulic support, and remotely control the attitude and pressure adjustment of the hydraulic support through the controller.

[0088] Based on the monitoring data of various sensors, the stability of the roof is monitored, and a stability monitoring and early warning model is established. The roof stability of the working face is dynamically divided. The roof situation is accurately judged through the stability monitoring and early warning model to ensure that the working face uses a suitable hydraulic support pressure regulation strategy, and the situation of the roof in front of the working face is judged in advance, and the hydraulic support pressure regulation strategy is adjusted in advance. Different support strategies are adopted for different areas of the working face to ensure support strength and accelerate the rotation and sinking of the roof and the crushing of the coal seam. When the hydraulic support moves forward, different frame moving strategies can be used according to the roof situation to ensure support strength; for the posture monitoring of the hydraulic support, when the posture of the hydraulic support is abnormal, it can be adjusted in time, and based on the abnormal posture of the support, its pressure regulation strategy can be adjusted to fit the underground working conditions, achieve stable support and ensure creep pressure relief effect; the roof stability monitoring uses a neural network to adaptively judge the pressure characteristics in front of the roof sinking pressure area or the roof crushing area, and issue corresponding early warning signals based on the judged characteristics.

[0089] like Figure 2 As shown in the figure, it is a schematic diagram of the roof collapse process. As the roof sinks, the pressure will move forward in the direction of advancement. At this time, reducing the bearing pressure of the support can increase the bearing pressure of the coal wall, and using natural pressure to break the thick hard coal wall. When advancing to the vicinity of the fracture line, the roof drops sharply and the stability becomes lower. At this time, the support strength is guaranteed. After advancing through the fracture line, the existing broken roof settles to the rear of the support, which can reduce the bearing pressure of the hydraulic support and accelerate the sinking of the front roof.

[0090] The above description is only a preferred embodiment of the present invention and does not limit the present invention. Any modifications, equivalent substitutions and improvements made within the spirit and principle of the present invention should be included in the scope of protection of the present invention.

Claims

1. A roof stability monitoring and control method based on hydraulic support, characterized in that: The hydraulic support is equipped with sensors for monitoring the bearing pressure, sensors for monitoring the support angle and tilt, and sensors for monitoring the propulsion stroke. It is also equipped with pressure limiting components, control components, and data transmission components. A roof stability monitoring and early warning model is also established: S1. Identification and judgment of hydraulic support top plate features: 1) Based on the pressure data of the hydraulic support monitored by the sensor, determine whether the roof working surface is in the roof subsidence pressure area, identify the location of the roof subsidence pressure area and determine the pressure intensity: 2) Based on the mine pressure data, identify the areas with high-pressure hydraulic supports within the range. Determine the pressure-bearing conditions, resistance increase, and high-pressure duration of the hydraulic supports in these areas to determine whether they belong to the roof subsidence pressure area. For the identified roof subsidence pressure area, record and analyze the area size and resistance increase pressure degree. 3) Based on the hydraulic support pressure data monitored by the sensor, determine whether the roof working surface is in the roof crushing zone, and identify the location and degree of crushing of the roof crushing zone: 4) Based on the mine pressure data, identify the areas with concentrated low-pressure hydraulic supports within the range, determine the pressure bearing conditions, resistance increase conditions and low-pressure duration of the hydraulic supports in these areas, eliminate the causes of the hydraulic supports' own failures based on the actual working condition data of the hydraulic supports, and determine whether they belong to the roof crushing area. For the identified roof crushing area, record and analyze the area size and crushing degree; S2. Hydraulic support posture recognition and judgment: 1) Based on the inclination and posture data of each part of the hydraulic support monitored by the sensor, determine whether the hydraulic support has any abnormal posture; 2) Based on the difference in pitch angles between the top beam and base of the hydraulic support, determine whether the hydraulic support is in an abnormal posture with a top beam elevation angle that is too large or too small. Based on the difference in the roll angle of the hydraulic support base and the corresponding angle data of the working face or coal mining machine, determine whether the hydraulic support is tilted or at risk of tipping over. 3) Based on the posture data of the hydraulic supports on the working face monitored by sensors, it is determined whether there are any adjacent hydraulic supports in an abnormal overlapping state; 4) Based on the mining height data of adjacent hydraulic supports monitored by sensors, determine whether the hydraulic supports are too high or too low, resulting in gaps in the hydraulic support support for gangue to pass through; based on the pitch angle data of the top beams of adjacent hydraulic supports monitored by sensors, determine whether the top beams of the hydraulic supports are greatly offset, resulting in support holes at the head or tail of the top beams; based on the roll angle data of the bases of adjacent hydraulic supports monitored by sensors, determine whether the top beams of adjacent hydraulic supports are squeezed and collided or support holes are present; S3. Determination of the point of action of the resultant force on the roof: 1) Based on the hydraulic support posture data and pressure data monitored by the sensor, determine the position of the resultant force acting on the hydraulic support by the top plate at the top beam, and calculate and determine the position of the resultant force acting point based on the top beam pressure data; S4. Special roof feature warning: 1) Based on the pressure data, posture data and the position of the resultant force point of the hydraulic support monitored by sensors, the roof features in front of the hydraulic support are predicted and analyzed. When special roof features are analyzed, an early warning is issued to the corresponding area of ​​the working surface; S5. Dynamic zoning of roof stability: Based on the working face roof characteristic monitoring data and prediction analysis results, a working face roof stability model is constructed. Dynamic zoning is performed based on roof stability, dividing the area into a stable roof zone, a rotation acceleration zone, and an instability risk zone. Based on the results of this dynamic zoning, different hydraulic support pressure regulation strategies are implemented for different areas. The criteria for determining the dynamic zoning of roof stability are: 1) Roof stability zone: ① There is no roof sinking pressure zone or roof crushing zone in the area; ② There is no special roof area warning in the area; ③ There is no abnormal posture of hydraulic support in the area; ④ The combined force application point of the hydraulic support is in the middle of the roof beam; 2) Rotation acceleration zone: ① There are no roof sinking pressure areas or roof crushing areas in the area; ② There are no special roof area warnings in the area, or there are low-risk warnings; ③ There are no abnormal hydraulic support postures in the area, or there are abnormal roof beam pitch angles; ④ The hydraulic support force action point is offset toward the front of the roof beam; 3) Instability risk areas: ① There may be roof subsidence and roof crushing areas in the area; ② There are special roof area high risk warnings in the area; ③ There are abnormal overlap and pitch angles of hydraulic supports in the area; ④ The combined force application point of the hydraulic supports is at the front or rear of the roof beam; Different hydraulic support pressure regulation strategies are implemented in different areas: for the roof stable area, the pressure regulation strategy is creep pressure relief, 2-3 pressure relief supports are arranged between the pressure-bearing hydraulic supports, and the pressure relief supports use top-wiping frame moving safety valves to control flow and pressure relief, so that the column will not fall quickly during the pressure relief process and the overlap with the adjacent supports is normal; Rotation acceleration zone: The pressure regulation strategy is creep pressure relief. 0-1 pressure relief supports are arranged at intervals between the pressure-bearing hydraulic supports. The initial support force and working resistance of the pressure relief supports are greater than those in the roof stability zone. The pressure relief supports use a top-rubbing frame moving safety valve to control the flow and pressure relief, so that the column does not drop during the pressure relief process and the overlap with the adjacent supports is normal. If there are hydraulic supports with abnormal postures, they will be adjusted in real time to normal support; Instability risk area: The pressure regulation strategy is to add fluid to bear pressure. All hydraulic supports are pressure-bearing supports, and no pressure-yielding supports are configured. The hydraulic support posture is dynamically adjusted according to the predicted data of roof stability, and the support continuity and stability of the hydraulic support are ensured by the top-wiping and frame-shifting safety valve; S6. Single hydraulic support pressure and attitude control: The pressure-bearing sensors on the hydraulic support monitor the roof pressure and distribution in real time, and the support attitude is fed back through the sensors that monitor the support angle and inclination. The single hydraulic support is controlled by the control component, the output of each jack of the hydraulic support is adjusted, the spatial position of each part of the hydraulic support is controlled, and the pressure of the hydraulic support is adjusted by the top-wiping frame shifting safety valve. The hydraulic support is regulated according to the different roof stability targets, so that the hydraulic support can achieve creep pressure relief, fluid replenishment pressure relief, column lowering pressure relief and top beam attitude adjustment to control the pressure of the hydraulic support. The data transmission component can transmit the data monitored by each sensor to the upper computer, monitor the pressure, attitude state and height of the hydraulic support in real time, identify and locate possible single-frame attitude anomalies, instability during the frame shifting process, and abnormal areas of multiple-frame attitude groups, provide auxiliary information for remote control of the hydraulic support, and remotely control the attitude and pressure adjustment of the hydraulic support through the controller.

2. The method for monitoring and controlling roof stability based on a hydraulic support according to claim 1, characterized in that: The sensors for monitoring the bearing pressure include a column pressure sensor, a balancing jack pressure sensor and a top beam pressure grating sensor; the sensors for monitoring the angle of inclination of the support include a base inclination sensor, a connecting rod inclination sensor, a top beam inclination sensor and a guard plate inclination sensor; the sensors for monitoring the propulsion stroke include an infrared receiver and a displacement sensor; the pressure limiting component includes a top-wiping frame safety valve, which can control the hydraulic support to slowly release pressure at a small flow rate and quickly release pressure at a large flow rate, to erect or lower the hydraulic support column; the control component includes a controller, which controls the solenoid valve driver, and the solenoid valve driver controls the electro-hydraulic reversing valve group on the hydraulic support to control the action of the hydraulic support; the data transmission component includes a controller cable and a sensor cable.

3. The method for monitoring and controlling roof stability based on a hydraulic support according to claim 1, characterized in that: Roof stability monitoring uses a neural network to adaptively judge the pressure characteristics in front of the roof sinking pressure area or the roof crushing area, and issues corresponding early warning signals based on the judged characteristics.

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