Multi-field coupling coal pillar stability control method and device for narrow and small coal pillar in fully-mechanized caving mining with secondary recovery
By constructing a multi-field coupled mathematical model and a collaborative control method, the problems of inaccurate coal pillar stability assessment and insufficient dynamic regulation during the remining process were solved, realizing the stability control of the coal pillar throughout its entire life cycle and improving the safety of remining.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- DATONG MINING YANZHOU CITY SHANDONG PROV
- Filing Date
- 2026-03-25
- Publication Date
- 2026-06-09
Smart Images
Figure CN122169815A_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of coal mining safety technology, and discloses a method and device for stability control of narrow coal pillars in multi-field coupled longwall mining. Background Technology
[0002] Remining is the secondary recovery of remaining coal resources in already mined areas, and it is of great significance in the context of tight coal resources. In fully mechanized longwall mining faces, narrow coal pillars serve as key structures for roadway isolation and stress transfer, and their stability directly determines the safety of mining.
[0003] However, during the remining process, the coal pillar faces complex multi-field coupling effects, and existing stability control methods have many technical defects: traditional control methods are mostly based on single stress field analysis, ignoring the coupled effects of damage, seepage, and temperature fields on the stability of the coal pillar, resulting in inaccurate assessment of the coal pillar's stability state and a lack of targeted control strategies; the calculation of the ultimate bearing capacity of the coal pillar and the mining load does not consider the parameter degradation caused by multi-field coupling, resulting in large deviations in the calculation results and failing to provide a reliable basis for stability control; the control methods are simplistic, mostly using single grouting reinforcement or support methods, failing to carry out differentiated and coordinated control according to the characteristics of different stability zones of the coal pillar, resulting in limited control effects; and there is a lack of dynamic monitoring and feedback control mechanisms throughout the entire life cycle, with control parameters remaining fixed and unable to adapt to the dynamic changes in the state of the coal pillar during the remining process, which easily leads to the risk of later instability. Summary of the Invention
[0004] The existing control methods of this invention have technical problems such as ignoring the influence of multi-field coupling, inaccurate evaluation, single control mode, and lack of dynamic regulation. Therefore, this invention provides a method and device for stability control of narrow coal pillars in multi-field coupled fully mechanized longwall mining.
[0005] To achieve the above-mentioned technical effects, the technical solution adopted by this invention is: a multi-field coupled fully mechanized longwall mining method for controlling the stability of narrow coal pillars, comprising the following steps: S1: Collect basic parameters of the coal and rock mass through downhole drilling inspection, stress monitoring, water pressure monitoring, and ground temperature testing; S2: Based on the aforementioned basic parameters, construct a four-field coupled mathematical model of stress-damage-seepage-temperature for the coal pillar; S3: Based on the stress-damage-seepage-temperature four-field coupled mathematical model, calculate the stability coefficient of the coal pillar, divide the coal pillar into regions based on the stability coefficient, and determine the range of stable regions; S4: Based on the range of the stable area, the coal pillar is reinforced and depressurized by a coordinated control method of deep and shallow hole layered grouting reinforcement, constant resistance large deformation anchor cable coordinated support, and large diameter precise pressure relief. S5: The basic parameters are periodically monitored in real time through monitoring equipment to obtain dynamic monitoring data; the monitoring data is fed back to the four-field coupled mathematical model to dynamically correct the model parameters, and the control parameters are adjusted based on the correction results to achieve dynamic stability control of the coal pillar throughout its entire life cycle.
[0006] As a preferred embodiment, in step S3, the stability coefficient is the ratio of the ultimate bearing capacity of the coal pillar to the mining load. When the stability coefficient is ≥1.2, the coal pillar is stable; when 1.0 < stability coefficient <1.2, it is critically stable; and when the stability coefficient is ≤1.0, it is unstable. Based on the stability coefficient and the distribution of the plastic zone of the coal pillar, the stable region of the coal pillar is obtained, which includes the stable region, the plastic development region, and the critical instability region.
[0007] As a preferred embodiment, the formula for calculating the ultimate bearing capacity of the coal pillar is: ; Among them, R c D represents the ultimate bearing capacity of the coal pillar, and D represents the damage variable. Where B is the uniaxial compressive strength of the coal and rock mass, H is the width of the coal pillar, S is the height of the coal pillar, and S is the bearing area of the coal pillar. Temperature reduction factor, This is the seepage reduction factor; The formula for calculating the mining load on the coal pillar is: ; Where F is the mining load, K is the stress concentration factor of the mining operation, γ is the average unit weight of the overburden, and L is the length of the coal pillar.
[0008] As a preferred embodiment, in the stress-damage-seepage-temperature four-field coupled mathematical model, the damage variable is defined by the elastic modulus degradation method, resulting in the damage-stress coupled constitutive equation: ; Where E is the elastic modulus of the damaged coal and rock mass, E0 is the initial elastic modulus, D0 is the initial damage degree before remining, and ΔD i Let α be the increment of damage caused by the disturbance during the i-th mining attempt. w P is the seepage water pressure damage coefficient. w Pore water pressure; Based on the cubic law, the seepage-damage coupling equation is obtained: ; Where k is the permeability coefficient, k0 is the initial permeability coefficient, and β is the damage permeability coefficient growth factor; The accelerating effect of temperature stress on coal pillar damage leads to the temperature-stress-damage coupling equation: ; Where, σ T For temperature stress, α T ΔT is the thermal expansion coefficient of the coal and rock mass, and ΔT is the difference between the ground temperature and the ambient temperature.
[0009] As a preferred embodiment, in step S5, the monitoring equipment includes a stress sensor, a pore water pressure sensor, a temperature sensor, and a displacement monitoring point, and the monitoring cycle is at least 3 months. When the stability coefficient obtained from real-time monitoring is lower than the critical value, it is corrected by strengthening grouting and support.
[0010] Based on the above method, the present invention also proposes a stability control device for narrow coal pillars in multi-field coupled fully mechanized longwall mining, comprising: The data acquisition module is used to collect basic parameters of coal and rock masses through downhole drilling, stress monitoring, water pressure monitoring, and ground temperature testing. The model building module is used to construct a four-field coupled mathematical model of stress, damage, seepage, and temperature of the coal pillar based on the aforementioned basic parameters. The stability coefficient calculation and region division module is used to calculate the stability coefficient of the coal pillar based on the stress-damage-seepage-temperature four-field coupled mathematical model, and to divide the coal pillar into regions based on the stability coefficient to determine the range of stable regions. The collaborative control module is used to reinforce and depressurize the coal pillar by adopting a collaborative control method of deep and shallow hole layered grouting reinforcement, constant resistance large deformation anchor cable collaborative support, and large diameter precise pressure relief, according to the range of the stable area. The dynamic monitoring and feedback control module is used to periodically monitor the basic parameters in real time through monitoring equipment to obtain dynamic monitoring data; feed the monitoring data back to the four-field coupled mathematical model to dynamically correct the model parameters, and adjust the control parameters based on the correction results to achieve dynamic stability control of the coal pillar throughout its entire life cycle.
[0011] In a preferred embodiment, the formula for calculating the ultimate bearing capacity of the coal pillar in the stability coefficient calculation and region division module is as follows: ; Among them, R c D represents the ultimate bearing capacity of the coal pillar, and D represents the damage variable. Where B is the uniaxial compressive strength of the coal and rock mass, H is the width of the coal pillar, S is the height of the coal pillar, and S is the bearing area of the coal pillar. Temperature reduction factor, This is the seepage reduction factor; The formula for calculating the mining load on the coal pillar is: ; Where F is the mining load, K is the stress concentration factor of the mining operation, γ is the average unit weight of the overburden, and L is the length of the coal pillar.
[0012] As a preferred embodiment, the stress-damage-seepage-temperature four-field coupled mathematical model in the stability coefficient calculation and region division module includes: The damage-stress coupled constitutive equation defines the damage variable using the elastic modulus degradation method: ; Where E is the elastic modulus of the damaged coal and rock mass, E0 is the initial elastic modulus, D0 is the initial damage degree before remining, and ΔD i Let α be the increment of damage caused by the disturbance during the i-th mining attempt. w P is the seepage water pressure damage coefficient. w Pore water pressure; Based on the cubic law, the seepage-damage coupling equation is obtained: ; Where k is the permeability coefficient, k0 is the initial permeability coefficient, and β is the damage permeability coefficient growth factor; The accelerating effect of temperature stress on coal pillar damage leads to the temperature-stress-damage coupling equation: ; Where, σ T For temperature stress, α T ΔT is the thermal expansion coefficient of the coal and rock mass, and ΔT is the difference between the ground temperature and the ambient temperature.
[0013] As a preferred embodiment, the monitoring equipment in the dynamic monitoring and feedback control module includes a stress sensor, a pore water pressure sensor, a temperature sensor, and a displacement monitoring point, with a monitoring cycle of at least 3 months; when the stability coefficient obtained from real-time monitoring is lower than the critical value, it is corrected by strengthening grouting and support.
[0014] As a preferred implementation, the collaborative control module includes a layered grouting reinforcement of deep and shallow holes, a collaborative support system of constant resistance and large deformation anchor cables, and a collaborative control method of large-diameter precise pressure relief. These methods are used to enhance the overall strength of the coal pillar, provide active support force, and release local high stress concentration, so as to achieve differentiated control of the coal pillar by zone.
[0015] Compared with existing technologies, this invention calculates the relative margin and risk component of water quality indicators and obtains a smoothed risk value by combining it with exponential moving average processing. This eliminates the interference of instantaneous fluctuations in monitoring data and achieves stable and accurate perception of water quality risks. Furthermore, based on the smoothed risk value, it achieves adaptive scheduling of optimized weights and soft target scaling coefficients. When the risk is low, it focuses on operational economy, and when the risk is high, it focuses on water quality compliance. This solves the technical defect of traditional methods that cannot adapt to water quality fluctuations due to fixed weights.
[0016] The constructed comprehensive reward function integrates compliance penalty terms, shape reward terms, and smoothing penalty terms. It enforces compliance penalty terms to ensure that the effluent water quality meets the standards, guides the water quality towards a better target through shape reward terms, and suppresses control action jitter through smoothing penalty terms. This achieves synergistic optimization of the three major objectives of effluent water quality compliance, lowest operating cost, and stable control actions.
[0017] The normalized control actions output by the pre-trained reinforcement learning policy network are converted into engineering-executable control variables through linear mapping. At the same time, smoothing constraints are applied to the control actions, which solves the problems of disconnect between traditional reinforcement learning output and engineering practice and easy jitter of control actions. This greatly improves the engineering executability of the algorithm and the operational stability of the sewage treatment system.
[0018] It adopts a closed-loop control process of data acquisition, risk perception, parameter scheduling, action output and execution feedback. After a single control cycle is completed, the entire process is repeated. It can track the changes in the operating status of the sewage treatment system in real time, adapt to complex operating conditions such as fluctuations in influent water quality and drift of process parameters, and ensure the continuity and stability of the control effect.
[0019] All calculations use standardized mathematical expressions without complex iterative operations. It can be deployed based on the existing online monitoring system and PLC control system of the sewage treatment plant without large-scale modification of existing hardware equipment, thus reducing the cost of engineering applications and having strong practicality and promotion value. Attached Figure Description
[0020] Figure 1 This is a flowchart illustrating the stability control method for narrow coal pillars in multi-field coupled fully mechanized longwall mining according to the present invention. Figure 2 This is a flowchart of the stability control device for narrow coal pillars in fully mechanized longwall mining faces based on multi-field coupling, according to the present invention.
[0021] In the diagram: 1. Data acquisition module; 2. Model building module; 3. Stability coefficient calculation and region division module; 4. Collaborative control module; 5. Dynamic monitoring and feedback regulation module. Detailed Implementation
[0022] The present invention will now be described in further detail with reference to the embodiments and accompanying drawings. However, this should not be construed as limiting the scope of the above-described subject matter of the present invention to the following embodiments; all technologies implemented based on the content of the present invention fall within the scope of the present invention.
[0023] refer to Figure 1Example 1: A method for stability control of narrow coal pillars in multi-field coupled fully mechanized longwall mining. This method achieves full life-cycle stability control of narrow coal pillars through multi-field coupled modeling, stability zoning, collaborative control, and dynamic feedback. Specifically, it includes the following steps: S1: Collect basic parameters of coal and rock mass. Through methods such as downhole drilling inspection, stress monitoring, water pressure monitoring, and geothermal testing, the basic parameters of coal and rock mass are collected in a comprehensive manner, including uniaxial compressive strength, elastic modulus, initial damage degree, permeability coefficient, thermal expansion coefficient, average bulk density of overburden, pore water pressure, geothermal temperature, etc., to provide data support for subsequent model construction.
[0024] S2: Constructing a four-field coupled mathematical model. Based on the acquired basic parameters, a four-field coupled mathematical model of stress, damage, seepage, and temperature is constructed for the coal pillar. This model comprehensively considers the interactions and coupling effects between the fields, specifically including: ① Damage-stress coupling constitutive equation: The damage variable is defined by the elastic modulus degradation method, and the expression is: ; Where E is the elastic modulus of the damaged coal and rock mass, E0 is the initial elastic modulus, D0 is the initial damage degree before remining, and ΔD i Let α be the increment of damage caused by the disturbance during the i-th mining attempt. w P is the seepage water pressure damage coefficient. w Pore water pressure; ② Seepage-Damage Coupling Equation: Based on the cubic law, it describes the effect of damage on the permeability coefficient, and its expression is: ; Where k is the permeability coefficient, k0 is the initial permeability coefficient, and β is the damage permeability coefficient growth factor; ③ Temperature-Stress-Damage Coupling Equation: Considering the accelerating effect of temperature stress on coal pillar damage, the expression is: ; Where, σ T For temperature stress, α T ΔT is the thermal expansion coefficient of the coal and rock mass, and ΔT is the difference between the ground temperature and the ambient temperature.
[0025] S3: Calculate the stability coefficient and delineate stable regions. Based on the coupled mathematical model of stress-damage-seepage-temperature, calculate the ultimate bearing capacity of the coal pillar and the mining load, and then obtain the stability coefficient. Based on the stability coefficient and the distribution of the plastic zone, delineate stable regions: ① Formula for calculating the ultimate bearing capacity of a coal pillar: ; Among them, R c D represents the ultimate bearing capacity of the coal pillar, and D represents the damage variable. Where B is the uniaxial compressive strength of the coal and rock mass, H is the width of the coal pillar, S is the height of the coal pillar, and S is the bearing area of the coal pillar. Temperature reduction factor, This is the seepage reduction factor; ②The formula for calculating the mining load on the coal pillar is: ; Where F is the mining load, K is the stress concentration factor of the mining operation, γ is the average unit weight of the overburden, and L is the length of the coal pillar.
[0026] ③ Definition of stability coefficient: The stability coefficient is the ratio of the ultimate bearing capacity of the coal pillar to the mining load. When the stability coefficient is ≥1.2, the coal pillar is stable; when 1.0 < stability coefficient <1.2, it is critically stable; and when the stability coefficient is ≤1.0, it is unstable. ④ Stable Zone Division: Combining the stability coefficient and the distribution of the plastic zone of the coal pillar, the coal pillar is divided into three zones: stable zone, plastic development zone, and critical instability zone.
[0027] S4: Coordinated control of coal pillar stability. Based on the results of stable zone division, a coordinated control method is adopted, which includes deep and shallow hole layered grouting reinforcement, constant resistance large deformation anchor cable coordinated support, and large-diameter precise pressure relief, to carry out differentiated reinforcement and pressure relief for coal pillars in different zones. ①Deep and shallow hole layered grouting reinforcement: enhances the overall strength and integrity of the coal pillar, especially suitable for plastic development zone and critical instability zone; ② Constant resistance large deformation anchor cable coordinated support: provides continuous active support force, inhibits coal pillar deformation, and is adapted to the large deformation characteristics of coal pillar; ③ Large-diameter precision pressure relief: Releases local high stress concentration, avoids stress superposition leading to coal pillar instability, and is mainly used in areas with high stress concentration.
[0028] S5: Dynamic monitoring and feedback control: By periodically monitoring basic parameters in real time through monitoring equipment, dynamic monitoring data is obtained, and dynamic control throughout the entire life cycle is achieved based on data feedback. The monitoring equipment includes stress sensors, pore water pressure sensors, temperature sensors, and displacement monitoring points, with a monitoring cycle of no less than 3 months. Real-time monitoring data is fed back to the four-field coupled mathematical model to dynamically correct parameters such as damage variables, permeability coefficient, and temperature stress in the model. The stability coefficient is recalculated based on the revised model. If the stability coefficient is lower than the critical value (1.2), the stability of the coal pillar can be dynamically controlled by adjusting the control parameters through enhanced grouting and support.
[0029] refer to Figure 2A multi-field coupled fully mechanized longwall mining narrow coal pillar stability control device is a hardware and software integrated system for implementing the above methods. It includes five functional modules, each working collaboratively to complete the entire process control of coal pillar stability. The specific structure is as follows: Data acquisition module 1: Used to collect basic parameters of coal and rock mass through methods such as downhole borehole inspection, stress monitoring, water pressure monitoring, and ground temperature testing; Model building module 2: Used to construct a four-field coupled mathematical model of stress-damage-seepage-temperature of the coal pillar based on the collected basic parameters, including three sets of coupled equations: damage-stress, seepage-damage, and temperature-stress-damage. Stability Coefficient Calculation and Region Division Module 3: This module is used to calculate the ultimate bearing capacity of the coal pillar, mining load and stability coefficient based on the four-field coupled mathematical model, and to divide the stable zone, plastic development zone and instability critical zone based on the distribution of the plastic zone. Collaborative Control Module 4: Based on the stable zone division results, it adopts a collaborative control method of deep and shallow hole layered grouting reinforcement, constant resistance large deformation anchor cable collaborative support, and large diameter precise pressure relief to carry out zoned differentiated reinforcement and pressure relief of coal pillars. Dynamic monitoring and feedback control module 5: It is used to collect dynamic monitoring data through monitoring equipment, feed it back to the four-field coupled mathematical model and correct the parameters, and adjust the control parameters based on the correction results to achieve dynamic stability control of the coal pillar throughout its entire life cycle.
[0030] In the stability coefficient calculation and regional division module 3, the calculation formulas for the ultimate bearing capacity of the coal pillar and the mining load, and the specific expressions of the four-field coupled mathematical model are consistent with the above methods; the monitoring equipment of the dynamic monitoring and feedback control module 5 includes stress sensors, pore water pressure sensors, temperature sensors and displacement monitoring points, with a monitoring cycle of no less than 3 months, and the strengthening correction mechanism is activated when the stability coefficient is lower than the critical value.
[0031] The above description is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the principle of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.
Claims
1. A method for stability control of narrow coal pillars in multi-field coupled longwall mining, characterized in that, Includes the following steps: S1: Collect basic parameters of the coal and rock mass through downhole drilling inspection, stress monitoring, water pressure monitoring, and ground temperature testing; S2: Based on the aforementioned basic parameters, construct a four-field coupled mathematical model of stress-damage-seepage-temperature for the coal pillar; S3: Based on the stress-damage-seepage-temperature four-field coupled mathematical model, calculate the stability coefficient of the coal pillar, divide the coal pillar into regions based on the stability coefficient, and determine the range of stable regions; S4: Based on the range of the stable area, the coal pillar is reinforced and depressurized by a coordinated control method of deep and shallow hole layered grouting reinforcement, constant resistance large deformation anchor cable coordinated support, and large diameter precise pressure relief. S5: The basic parameters are periodically monitored in real time through monitoring equipment to obtain dynamic monitoring data; the monitoring data is fed back to the four-field coupled mathematical model to dynamically correct the model parameters, and the control parameters are adjusted based on the correction results to achieve dynamic stability control of the coal pillar throughout its entire life cycle.
2. The stability control method for narrow coal pillars in multi-field coupled fully mechanized longwall mining according to claim 1, characterized in that, In step S3, the stability coefficient is the ratio of the ultimate bearing capacity of the coal pillar to the mining load. When the stability coefficient is ≥1.2, the coal pillar is stable; when 1.0 < stability coefficient <1.2, it is critically stable; and when the stability coefficient is ≤1.0, it is unstable. Based on the stability coefficient and the distribution of the plastic zone of the coal pillar, the stable region of the coal pillar is obtained, which includes the stable region, the plastic development region, and the critical instability region.
3. The stability control method for narrow coal pillars in multi-field coupled fully mechanized longwall mining according to claim 2, characterized in that, The formula for calculating the ultimate bearing capacity of the coal pillar is as follows: ； Among them, R c D represents the ultimate bearing capacity of the coal pillar, and D represents the damage variable. Where B is the uniaxial compressive strength of the coal and rock mass, H is the width of the coal pillar, S is the height of the coal pillar, and S is the bearing area of the coal pillar. Temperature reduction factor, This is the seepage reduction factor; The formula for calculating the mining load on the coal pillar is: ； Where F is the mining load, K is the stress concentration factor of the mining operation, γ is the average unit weight of the overburden, and L is the length of the coal pillar.
4. The stability control method for narrow coal pillars in multi-field coupled fully mechanized longwall mining according to claim 3, characterized in that, In the aforementioned stress-damage-seepage-temperature four-field coupled mathematical model, the damage variable is defined using the elastic modulus degradation method, resulting in the damage-stress coupled constitutive equation: ； Where E is the elastic modulus of the damaged coal and rock mass, E0 is the initial elastic modulus, D0 is the initial damage degree before remining, and ΔD i Let α be the increment of damage caused by the disturbance during the i-th mining attempt. w P is the seepage water pressure damage coefficient. w Pore water pressure; Based on the cubic law, the seepage-damage coupling equation is obtained: ； Where k is the permeability coefficient, k0 is the initial permeability coefficient, and β is the damage permeability coefficient growth factor; The accelerating effect of temperature stress on coal pillar damage leads to the temperature-stress-damage coupling equation: ； Where, σ T For temperature stress, α T ΔT is the thermal expansion coefficient of the coal and rock mass, and ΔT is the difference between the ground temperature and the ambient temperature.
5. The stability control method for narrow coal pillars in multi-field coupled fully mechanized longwall mining according to claim 4, characterized in that, In step S5, the monitoring equipment includes a stress sensor, a pore water pressure sensor, a temperature sensor, and a displacement monitoring point, with a monitoring cycle of at least 3 months. When the stability coefficient obtained from real-time monitoring is lower than the critical value, it is corrected by strengthening grouting and support.
6. A stability control device for narrow coal pillars in multi-field coupled fully mechanized longwall mining, characterized in that, include: The data acquisition module (1) is used to collect basic parameters of coal and rock mass through downhole drilling, stress monitoring, water pressure monitoring, and ground temperature testing; Model building module (2) is used to build a four-field coupled mathematical model of stress-damage-seepage-temperature of the coal pillar based on the basic parameters. The stability coefficient calculation and region division module (3) is used to calculate the stability coefficient of the coal pillar according to the stress-damage-seepage-temperature four-field coupled mathematical model, and to divide the coal pillar into regions according to the stability coefficient to determine the range of stable regions. The collaborative control module (4) is used to reinforce and depressurize the coal pillar by adopting a collaborative control method of deep and shallow hole layered grouting reinforcement, constant resistance large deformation anchor cable collaborative support, and large diameter precise pressure relief according to the range of the stable area. The dynamic monitoring and feedback control module (5) is used to periodically monitor the basic parameters in real time through monitoring equipment, obtain dynamic monitoring data, feed the monitoring data back to the four-field coupled mathematical model, dynamically correct the model parameters, and adjust the control parameters based on the correction results to achieve dynamic stability control of the coal pillar throughout its entire life cycle.
7. The stability control device for narrow coal pillars in multi-field coupled fully mechanized longwall mining according to claim 6, characterized in that, In the stability coefficient calculation and regional division module (3), the formula for calculating the ultimate bearing capacity of the coal pillar is: ； Among them, R c D represents the ultimate bearing capacity of the coal pillar, and D represents the damage variable. Where B is the uniaxial compressive strength of the coal and rock mass, H is the width of the coal pillar, S is the height of the coal pillar, and S is the bearing area of the coal pillar. Temperature reduction factor, This is the seepage reduction factor; The formula for calculating the mining load on the coal pillar is: ； Where F is the mining load, K is the stress concentration factor of the mining operation, γ is the average unit weight of the overburden, and L is the length of the coal pillar.
8. The stability control device for narrow coal pillars in multi-field coupled fully mechanized longwall mining according to claim 7, characterized in that, In the stability coefficient calculation and region division module (3), the stress-damage-seepage-temperature four-field coupled mathematical model includes: The damage-stress coupled constitutive equation defines the damage variable using the elastic modulus degradation method: ； Where E is the elastic modulus of the damaged coal and rock mass, E0 is the initial elastic modulus, D0 is the initial damage degree before remining, and ΔD i Let α be the increment of damage caused by the disturbance during the i-th mining attempt. w P is the seepage water pressure damage coefficient. w Pore water pressure; Based on the cubic law, the seepage-damage coupling equation is obtained: ； Where k is the permeability coefficient, k0 is the initial permeability coefficient, and β is the damage permeability coefficient growth factor; The accelerating effect of temperature stress on coal pillar damage leads to the temperature-stress-damage coupling equation: ； Where, σ T For temperature stress, α T ΔT is the thermal expansion coefficient of the coal and rock mass, and ΔT is the difference between the ground temperature and the ambient temperature.
9. The stability control device for narrow coal pillars in multi-field coupled fully mechanized longwall mining according to claim 8, characterized in that, In the dynamic monitoring and feedback control module (5), the monitoring equipment includes a stress sensor, a pore water pressure sensor, a temperature sensor and a displacement monitoring point, and the monitoring cycle is at least 3 months; when the stability coefficient obtained by real-time monitoring is lower than the critical value, it is corrected by strengthening grouting and support.
10. The stability control device for narrow coal pillars in multi-field coupled fully mechanized longwall mining according to claim 9, characterized in that, In the collaborative control module (4), the collaborative control methods of deep and shallow hole layered grouting reinforcement, constant resistance large deformation anchor cable collaborative support, and large diameter precise pressure relief are respectively used to enhance the overall strength of the coal pillar, provide active support force and release local high stress concentration, so as to realize the zoned differentiated control of the coal pillar.