Self-adaptive control method for underground coal mine hole sealing and grouting

Abstract

The invention discloses a self-adaptive control method for underground coal mine hole sealing and grouting, and belongs to the technical field of well hole packing. The method comprises the steps that plugging bags are sequentially installed at the cross sections of two drill holes of an underground coal mine working face, compressed air is injected into the plugging bags, and a cylindrical space between the bags is filled with multi-stage coal powder distribution materials in a layered mode and compacted; mixing ordinary Portland cement, a composite expanding agent, a carboxyl water reducer, a hydroxypropyl methyl cellulose stabilizer and water according to a preset ratio, and screening; stepwise pressure injection is implemented, and the grouting pressure and rate are regulated and controlled in a variable-rate climbing mode, a constant-pressure variable-speed mode and a proportional attenuation mode; and constant-temperature and constant-humidity maintenance is conducted on the grouting completion area, so that the desorption value of the drilling cuttings is reduced to a target value. According to the scheme, the grouting process parameters can be optimized, and the grouting quality is improved.

Description

Technical Field

[0001] The present application relates to the technical field of borehole sealing, and in particular to an adaptive control method for underground borehole sealing grouting in coal mines. Background Art

[0002] During coal mining, due to the influence of geological structure, mining disturbance and other factors, the surrounding rock of underground tunnels often has problems such as crack development and loose structure, which not only seriously affects the stability and service life of the tunnel, but also brings major hidden dangers to mine safety production. Especially under complex geological conditions, the degree of development of the surrounding rock fracture zone is often high. If it is not promptly and effectively managed, it may lead to tunnel deformation, roof collapse and other disasters. At the same time, the existence of goafs will also cause the movement and destruction of overlying rock formations, forming water channels, increasing the risk of mine water disasters. Traditional hole sealing grouting technology has many limitations in practical applications. First, conventional hole sealing materials such as cement mortar, chemical slurry, etc. are prone to slurry channeling and slurry stringing during the injection process, resulting in unsatisfactory grouting effect. Secondly, improper control of grouting pressure often causes further damage to the surrounding rock, which in turn aggravates the deterioration of geological conditions. In addition, the construction efficiency of traditional grouting technology is low, and it cannot effectively deal with multiple fracture systems under complex geological conditions.

[0003] In recent years, with the continuous development of mining technology and the increasing requirements for safe production, new types of hole-sealing grouting materials and processes have emerged. The application of dual-liquid slurry materials has greatly improved the grouting effect, and its rapid solidification characteristics have effectively solved the problem of easy loss of traditional single-liquid slurry materials. The introduction of polymer materials has improved the flexibility and durability of the grouting body, making the reinforcement effect more durable and reliable. However, these new materials still face problems such as high cost and complex construction process in practical applications. In terms of grouting technology, the development of segmented grouting technology has revealed new ideas for improving grouting quality. By reasonably dividing the number of grouting sections and accurately controlling the grouting parameters, the diffusion range and filling effect of the slurry can be significantly improved. However, how to accurately judge the degree of crack development and determine the optimal grouting parameters are still important problems faced in engineering practice. The lag of monitoring technology is also an important factor restricting the development of hole-sealing grouting technology. At present, the evaluation of grouting effect mainly relies on experience judgment and simple physical tests, lacking scientific and systematic monitoring methods. This makes the optimization and adjustment of grouting parameters lack a reliable basis, affecting the continuous improvement of grouting quality.

[0004] Therefore, a technical solution is urgently needed to optimize the grouting process parameters and improve the grouting quality. Summary of the invention

[0005] In order to solve the deficiencies of the prior art, the embodiment of the present application discloses an adaptive control method for underground sealing grouting in coal mines. The present application solves the technical problems that the fixed grouting parameters in the prior art easily cause uneven grouting or unstable sealing quality.

[0006] The embodiment of the present application discloses an adaptive control method for underground sealing grouting in a coal mine, comprising: sequentially installing sealing bags at two borehole sections of an underground working face of a coal mine and injecting compressed air, filling the cylindrical space between the bags with multi-graded coal powder materials in layers and compacting them; mixing and screening ordinary silicate cement, composite expansion agent, carboxyl water reducer, hydroxypropyl methylcellulose stabilizer and water in a preset ratio; implementing stepped pressure injection, and regulating the grouting pressure and rate by means of variable rate climbing, constant pressure variable speed and proportional attenuation; including: adopting stepped pressure injection The grouting pressure is divided into three stages for control; the pressure and rate response function is established to determine the pressure and rate matching range during the grouting process; an adaptive controller based on fuzzy neural network is constructed to dynamically adjust the grouting pressure and rate; the diffusion and penetration of slurry in the cracks are promoted by periodic pressure perturbations; the fluctuation parameters are dynamically adjusted according to the pressure response characteristics; the grouting area is maintained at a constant temperature and humidity to reduce the desorption value of the drill cuttings to the target value; the density of the sealing section, the slurry diffusion radius and the surrounding rock bonding strength are measured respectively, and the construction parameters are recorded.

[0007] In a possible implementation method, sealing bags are installed in sequence at two borehole sections of an underground working face of a coal mine and compressed air is injected, and multi-graded coal powder materials are filled in layers in the cylindrical space between the bags and compacted, including: selecting a grouting area at the underground working face of a coal mine; installing an inner layer sealing bag at a first preset distance from the end of the borehole, and expanding the bag to form a seal by injecting compressed air of a preset pressure; installing an outer layer sealing bag at a second preset distance from the end of the borehole, and expanding the bag to form a seal by injecting compressed air of a preset pressure; filling multi-graded coal powder materials in layers in the cylindrical space between the two sealing bags through the grouting holes of the outer layer sealing bag; filling the multi-graded coal powder materials with a layered filling method, and performing light compaction.

[0008] In a possible implementation, ordinary Portland cement, composite expansion agent, carboxyl water reducer, hydroxypropyl methylcellulose stabilizer and water in a preset ratio are mixed and screened, including: selecting cement-based slurry as the base material and performing a modification treatment; mixing ordinary Portland cement, composite expansion agent, carboxyl water reducer, hydroxypropyl methylcellulose stabilizer and water according to a preset ratio, and performing mixing and stirring for a preset time; maintaining the viscosity of the slurry at a preset value by adjusting the stirring speed; and screening the stirred slurry to remove agglomerates.

[0009] In one possible implementation, the grouting completed area is subjected to constant temperature and humidity maintenance to reduce the drill cuttings desorption value to a target value, including: using a constant temperature and humidity maintenance scheme to solidify and maintain the grouting completed area; adjusting environmental parameters by deploying heating plates and spray devices; adjusting the temperature and humidity balance of the maintenance area at preset time intervals; and monitoring the drill cuttings desorption value until it is reduced to below a preset target value.

[0010] In a possible implementation, the density of the sealing section, the slurry diffusion radius and the bonding strength of the surrounding rock are respectively measured, and the construction parameters are recorded, including: using the ultrasonic detection method to measure the density of the sealing section; using the drilling coring method to measure the slurry diffusion radius; using the pull-out test to measure the bonding strength with the surrounding rock; recording the construction parameters to establish a construction database.

[0011] In one possible implementation, the grouting pressure and rate are dynamically adjusted, including: using a variable rate climbing method to control the pressure increase stage; using a constant pressure variable speed method to control the pressure maintenance stage; using a proportional attenuation method to control the pressure reduction stage.

[0012] In a possible implementation, dynamically adjusting the fluctuation parameter according to the pressure response characteristic includes: ,in, Indicates time The pressure perturbation at represents the fluctuation amplitude, represents the angular frequency, Represents the attenuation coefficient.

[0013] In the adaptive control method for underground sealing grouting in a coal mine disclosed above, the embodiment of the present application can optimize the grouting process parameters and improve the grouting quality by combining the adaptive grouting control of fuzzy neural network with periodic perturbation. Specifically, through the adaptive control method, the grouting pressure and rate can be adjusted in real time to adapt to the heterogeneity of the coal body structure and the randomness of the crack distribution, so as to ensure that the slurry can evenly penetrate into the coal body cracks and improve the sealing quality. The use of periodic pressure perturbation can promote the diffusion and penetration of the slurry in the cracks, further improve the grouting effect, enable the slurry to fully fill the cracks, and enhance the stability and strength of the coal body. The adaptive control method can dynamically adjust the control parameters according to the pressure response characteristics during the grouting process, avoid excessive grouting pressure leading to coal body damage or new cracks, thereby improving construction safety. By accurately controlling the grouting parameters, the loss and enrichment of the slurry in the cracks can be reduced, material waste can be reduced, and construction costs can be saved. The present application does not require the addition of additional hardware equipment, and adaptive grouting control can be achieved only by optimizing the control algorithm, which simplifies the construction process and improves construction efficiency. The adaptive controller built based on fuzzy neural network has self-learning function and can dynamically adjust control parameters according to real-time data in the grouting process, which improves the intelligent level of grouting process. By recording actual construction parameters and establishing a construction database, it provides reference and basis for subsequent construction, which helps to improve the overall construction quality and efficiency.

[0014] In summary, this application significantly improves the quality and effect of underground sealing grouting in coal mines, while reducing construction costs and safety risks, and has important practical significance and technical value. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0016] Figure 1 A schematic flow chart of an adaptive control method for sealing and grouting in underground coal mines disclosed in an embodiment of the present application; Figure 2 A three-dimensional surface diagram of grouting hole pressure distribution disclosed in an embodiment of the present application; Figure 3 This is a performance comparison chart of a grouting control method disclosed in an embodiment of the present application. DETAILED DESCRIPTION

[0017] Various exemplary embodiments of the present disclosure will now be described in detail with reference to the accompanying drawings. It should be noted that the relative arrangement of components and steps, numerical expressions and numerical values ​​set forth in these embodiments do not limit the scope of the present disclosure unless otherwise specifically stated.

[0018] Those skilled in the art can understand that the terms "first", "second" and the like in the embodiments of the present disclosure are only used to distinguish different steps, devices or modules, etc., and neither represent any specific technical meaning nor represent the necessary logical order between them. It should also be understood that in the embodiments of the present disclosure, "multiple" can refer to two or more, and "at least one" can refer to one, two or more. It should also be understood that for any component, data or structure mentioned in the embodiments of the present disclosure, in the absence of explicit limitation or contrary revelation given in the context, it can generally be understood as one or more. In addition, the term "and / or" in the present disclosure is only a description of the association relationship of the associated objects, indicating that there can be three relationships, for example, A and / or B can represent: A exists alone, A and B exist at the same time, and B exists alone. In addition, the character " / " in the present disclosure generally indicates that the associated objects before and after are an "or" relationship. It should also be understood that the description of each embodiment in the present disclosure emphasizes the differences between the embodiments, and the same or similar parts can refer to each other. For the sake of brevity, they will not be repeated one by one.

[0019] At the same time, it should be understood that, for ease of description, the sizes of the various parts shown in the drawings are not drawn according to the actual proportional relationship. The following description of at least one exemplary embodiment is actually only illustrative and is by no means intended to limit the present disclosure and its application or use. The techniques, methods and devices known to ordinary technicians in the relevant fields may not be discussed in detail, but where appropriate, the techniques, methods and devices should be considered part of the specification. It should be noted that similar numbers and letters represent similar items in the following drawings, so once an item is defined in one drawing, it does not need to be further discussed in subsequent drawings.

[0020] In order to make the purpose, technical solution and advantages of the embodiments of the present application clearer, the technical solution in the embodiments of the present application will be clearly and completely described below in conjunction with the drawings in the embodiments of the present application. Obviously, the described embodiments are part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of this application.

[0021] Figure 1A flow chart of an adaptive control method for underground hole sealing grouting in a coal mine disclosed in an embodiment of the present application. It should be understood that in the existing coal mine grouting process, the stepped pressure injection scheme is usually controlled by preset fixed pressure and rate parameters. However, due to the heterogeneity of the coal body structure and the randomness of the crack distribution, the fixed parameter control scheme has obvious deficiencies in practical applications. First, the degree of development of coal body cracks has significant differences in space, and the permeability effects of different regions under the same grouting pressure are quite different. For example, in areas with dense crack development, the grouting pressure may be too high to cause rapid loss of slurry; while in areas with sparse crack development, the grouting pressure may not be enough to achieve effective penetration. Secondly, the cement-based slurry will undergo dynamic changes in rheological properties during transportation, and the viscosity will change with the increase of shear time and transportation distance, which will directly affect the actual injection effect. In addition, there are also large differences in the strength and pore characteristics of coal bodies in different regions. Fixed grouting parameters cannot adapt to this spatial heterogeneity, which can easily cause problems such as uneven grouting or unstable sealing quality.

[0022] In actual engineering applications, the fixed parameter control scheme still faces serious safety hazards and technical bottlenecks. When the grouting pressure exceeds the bearing capacity of the coal body, it may cause new cracks to form or the original cracks to expand, which not only affects the sealing effect, but also may cause local stress concentration and coal body damage. At the same time, improper grouting rate control can easily cause slurry to be enriched in certain areas, forming string or channeling phenomena, which not only wastes grouting materials, but also affects the overall performance of the sealing. More importantly, the mismatch between pressure and rate parameters may lead to insufficient slurry diffusion or uneven pressure distribution, making it difficult for the sealing effect to meet the expected requirements. These problems are difficult to be effectively solved in traditional fixed parameter control schemes, which seriously restricts the application effect and safety of the grouting process.

[0023] Based on the above problems, the development of an adaptive step-type grouting control system has important practical significance and technical necessity. The system captures the changes in rheological properties during slurry delivery in real time by establishing a pressure-rate response function, and dynamically adjusts the control parameters according to the actual grouting effect. Through the self-learning function of the fuzzy neural network controller, the system can automatically optimize the matching relationship between grouting pressure and rate according to the coal body characteristics and crack distribution characteristics in different regions. At the same time, the improved pressure fluctuation control scheme can promote the uniform diffusion of slurry in the crack network and improve the overall performance of the sealing hole. This intelligent control scheme does not require the addition of additional hardware equipment, and can be achieved only by optimizing the control algorithm, which has a strong engineering practice value. More importantly, the system can significantly improve the safety and reliability of the grouting process, reduce material waste, and reduce construction costs, which is of great significance for improving the safety level of coal mine production.

[0024] Specifically, if Figure 1 As shown, in step S101, plugging bags are sequentially installed at two borehole sections of the underground working face of the coal mine and compressed air is injected, and the cylindrical space between the bags is filled with multi-graded coal powder materials in layers and compacted. This includes: selecting a grouting area at the underground working face of the coal mine; installing an inner layer plugging bag at a first preset distance at the end of the borehole, and expanding the bag to form a seal by injecting compressed air of a preset pressure; installing an outer layer plugging bag at a second preset distance at the end of the borehole, and expanding the bag to form a seal by injecting compressed air of a preset pressure; filling the cylindrical space between the two plugging bags with multi-graded coal powder materials in layers through the grouting holes of the outer layer plugging bag; filling the multi-graded coal powder materials with a layered filling method, and performing light compaction.

[0025] Preferably, preparatory work before drilling plugging is carried out, a grouting area is selected on the underground working surface of the coal mine, and a plugging bag is used to treat the borehole. It should be noted that the bag is composited by a pressure-resistant rubber layer and a nylon fiber layer, a preset one-way inflation valve is connected to the inflation tube, and the outer bag is provided with a through grouting hole. The inflation tube is arranged along the borehole wall and extends to the outside of the borehole (the inner bag inflation tube can extend through the outer bag grouting hole). In one embodiment, the inner layer plugging bag is installed at a distance of 67.8 cm from the end of the borehole, and 0.39 MPa of compressed air is injected to expand the bag to form a hole wall seal, and then the inflation tube is pulled out. Then, the outer layer plugging bag is installed at a distance of 32.6 cm from the end of the borehole, and 0.39 MPa of compressed air is injected to expand the bag to form a hole wall seal, and then the inflation tube is pulled out. At the same time, the cylindrical space between the two sealing bags is filled with multi-graded coal powder materials through the grouting holes of the outer bag, of which coal powder with a particle size of 0.25-0.5 mm accounts for 37.2%, coal powder with a particle size of 0.5-1.0 mm accounts for 42.5%, and coal powder with a particle size of 1.0-2.0 mm accounts for 20.3%. During the filling process, the layered filling method is adopted, and the thickness of each layer is controlled at about 8 mm, and light compaction is performed to ensure the uniformity of the filling material.

[0026] At step S102, ordinary Portland cement, composite expansion agent, carboxyl water reducer, hydroxypropyl methylcellulose stabilizer and water in a preset ratio are mixed and screened. The process includes: selecting cement-based slurry as the base material and performing a modification process; mixing ordinary Portland cement, composite expansion agent, carboxyl water reducer, hydroxypropyl methylcellulose stabilizer and water in a preset ratio and performing a mixing and stirring process for a preset time; maintaining the viscosity of the slurry at a preset value by adjusting the stirring speed; and screening the stirred slurry to remove agglomerates.

[0027] In one embodiment, a grouting material is prepared, and a cement-based slurry is selected as the base material and modified. The specific ratio is: ordinary Portland cement accounts for 62.3%, composite expansion agent accounts for 8.7%, carboxyl water reducer accounts for 0.6%, hydroxypropyl methylcellulose stabilizer accounts for 0.4%, and the rest is water. The above materials are mixed and stirred in a stirring device according to the ratio for 12.5 minutes to make them fully uniform. During the stirring process, the initial temperature of the cement slurry is controlled at 16.8°C, and the viscosity of the slurry is maintained at 1.85Pa·s by adjusting the stirring speed. After the stirring is completed, screening is carried out to remove agglomerates to obtain a uniform grouting material.

[0028] At step S103, step-by-step pressure injection is implemented, and the grouting pressure and rate are regulated by variable rate ramping, constant pressure variable speed and proportional attenuation. This includes: adopting a step-by-step pressure injection scheme, dividing the grouting pressure into three stages for control; establishing a pressure and rate response function to determine the pressure and rate matching interval during the grouting process; constructing an adaptive controller based on a fuzzy neural network to dynamically adjust the grouting pressure and rate; promoting the diffusion and penetration of slurry in the cracks through periodic pressure perturbations; and dynamically adjusting the fluctuation parameters according to the pressure response characteristics.

[0029] Among them, the grouting pressure and rate are dynamically adjusted, including: using a variable rate climbing method to control the pressure increase stage; using a constant pressure variable speed method to control the pressure maintenance stage; using a proportional attenuation method to control the pressure reduction stage.

[0030] Among them, the fluctuation parameters are dynamically adjusted according to the pressure response characteristics, including: ,in, Indicates time The pressure perturbation at represents the fluctuation amplitude, represents the angular frequency, Represents the attenuation coefficient.

[0031] In one embodiment, the grouting process is controlled. A stepped pressure injection scheme is adopted, and the grouting pressure is divided into three stages: in the first stage, the pressure is gradually increased from 0 to 2.85MPa, the increase time lasts for 4.6 minutes, and the grouting rate is maintained at 2.3L / min; in the second stage, the pressure is stabilized between 2.85-3.15MPa, the duration is 18.3 minutes, and the grouting rate is adjusted to 1.7L / min; in the third stage, the pressure is gradually reduced to 0.92MPa, the pressure reduction time is 6.7 minutes, and the grouting rate is reduced to 0.8L / min. During the grouting process, the injection pressure and rate are adjusted so that the slurry can fully penetrate into the cracks of the coal body. To ensure the fluidity of the slurry, a slight pressure fluctuation is performed every 3.2 minutes during the grouting process, and the fluctuation amplitude is ±0.15MPa.

[0032] Further, specifically, when the grouting process is controlled, an adaptive step-by-step injection control scheme is established based on the dynamic relationship between the grouting pressure and the rate. First, a pressure-rate response function is established based on the rheological properties of the grouting material. By analyzing the relationship between the shear stress and the shear rate of the slurry during pipeline transportation, the functional relationship between the apparent viscosity μa of the slurry and the shear rate γ is obtained: μa = k·γ^(n-1), where k is the fluidity coefficient, which takes a value of 1.73, and n is the flow index, which takes a value of 0.86. Combined with the pressure loss calculation during pipeline transportation, the relationship between the grouting pressure P and the grouting rate Q is established: P =(8k·L / πR^4)·(3n+1 / 4n)^n·Q^n, where L is the length of the transportation pipeline, which takes a value of 28.6 meters, and R is the inner diameter of the pipeline, which takes a value of 0.023 meters. Based on this relationship, the pressure and rate matching interval during the grouting process is determined.

[0033] Based on the pressure-rate response relationship, an adaptive control model is constructed. The grouting pressure is used as the control variable and the grouting rate is used as the controlled variable to establish an adaptive controller based on a fuzzy neural network. The input variables of the controller include the current pressure value P(t), the pressure change rate ΔP(t) and the target pressure value P (t), and the output variable is the grouting rate adjustment value ΔQ(t). A five-layer network structure is adopted, with the first layer as the input layer, the second layer as the fuzzification layer, the third layer as the fuzzy rule layer, the fourth layer as the defuzzification layer, and the fifth layer as the output layer. In the fuzzification process, the input variables are fuzzified using the Gaussian membership function, and the membership function parameters are adaptively adjusted through online learning. The fuzzy rules adopt the Mamdani reasoning method, and the rule base contains 27 basic rules. In the defuzzification process, the centroid method is used for defuzzification operation.

[0034] Specifically, in the fuzzy rule layer, based on the pressure control variable P(t), the pressure change rate ΔP(t) and the target pressure value P (t) These three input variables construct a complete rule system. Each input variable is divided into three fuzzy subsets: the fuzzy subset of P(t) is {low pressure (L), medium pressure (M), high pressure (H)}, the fuzzy subset of ΔP(t) is {negative change (N), zero change (Z), positive change (P)}, and P The fuzzy subsets of (t) are {insufficient pressure (S), moderate pressure (M), excessive pressure (B)}.

[0035] According to the combination relationship of input variables, the following specific control rules are formulated: 9 rules when P(t) is low pressure: (1) If ΔP(t) is negative and P (t) is insufficient pressure, then ΔQ(t) increases significantly (VB); (2) if ΔP(t) changes negatively and P (t) is a moderate pressure, then ΔQ(t) increases moderately (B); (3) if ΔP(t) changes negatively and P (t) is too high, then ΔQ(t) takes a small increase (M); (4) If ΔP(t) is zero change and P (t) is insufficient pressure, then ΔQ(t) takes a moderate increase (B); (5) If ΔP(t) is zero change and P (t) is moderate pressure, then ΔQ(t) takes a small increase (M); (6) If ΔP(t) is zero change and P (t) is too high, then ΔQ(t) is kept constant (Z); (7) If ΔP(t) is positive and P (t) is insufficient pressure, then ΔQ(t) takes a small increase (M); (8) If ΔP(t) is positive and P (t) is moderate pressure, then ΔQ(t) is kept constant (Z); (9) If ΔP(t) is positive and P (t) is too high a pressure, then ΔQ(t) is slightly reduced (S).

[0036] 9 rules when P(t) is medium pressure: (10) If ΔP(t) is negative and P (t) is insufficient pressure, then ΔQ(t) increases moderately (B); (11) If ΔP(t) changes negatively and P (t) is moderate pressure, then ΔQ(t) increases slightly (M); (12) If ΔP(t) is negative and P (t) is too high, then ΔQ(t) is kept constant (Z); (13) If ΔP(t) is zero change and P (t) is insufficient pressure, then ΔQ(t) takes a small increase (M); (14) If ΔP(t) is zero change and P (t) is moderate pressure, then ΔQ(t) is kept constant (Z); (15) if ΔP(t) is zero change and P (t) is too high, then ΔQ(t) is slightly reduced (S); (16) If ΔP(t) is positive and P (t) is insufficient pressure, then ΔQ(t) is kept constant (Z); (17) If ΔP(t) is positive and P (t) is moderate pressure, then ΔQ(t) is slightly reduced (S); (18) If ΔP(t) is positive and P (t) is too high a pressure, then ΔQ(t) is reduced to a moderate value (VS).

[0037] 9 rules when P(t) is high pressure: (19) If ΔP(t) is negative and P (t) is insufficient pressure, then ΔQ(t) takes a small increase (M); (20) If ΔP(t) is negative and P (t) is moderate pressure, then ΔQ(t) remains unchanged (Z); (21) if ΔP(t) is negative and P (t) is too high, then ΔQ(t) is slightly reduced (S); (22) if ΔP(t) is zero change and P (t) is insufficient pressure, then ΔQ(t) is kept constant (Z); (23) If ΔP(t) is zero change and P (t) is moderate pressure, then ΔQ(t) takes a small decrease (S); (24) if ΔP(t) is zero change and P (t) is too high, then ΔQ(t) is reduced by a moderate amount (VS); (25) if ΔP(t) is positive and P (t) is insufficient pressure, then ΔQ(t) is slightly reduced (S); (26) If ΔP(t) is positive and P (t) is a moderate pressure, then ΔQ(t) takes a moderate decrease (VS); (27) if ΔP(t) is a positive change and P (t) is too high a pressure, then ΔQ(t) is greatly reduced (VVS).

[0038] Among the above 27 rules, the fuzzy subset of the output variable ΔQ(t) includes {substantially reduced (VVS), moderately reduced (VS), slightly reduced (S), unchanged (Z), slightly increased (M), moderately increased (B), and substantially increased (VB)}. These rules are constructed based on the physical characteristics of the grouting process and engineering experience, and can reasonably adjust the grouting rate according to the current pressure state, pressure change trend, and deviation from the target pressure, thereby achieving precise control of the grouting process.

[0039] Then, based on the established adaptive control model, the grouting process is controlled in sections. In the pressure increase stage, a variable rate ramping method is adopted, with the initial rate set at 1.2L / min, and the rate is gradually increased as the pressure increases. During the pressure increase process, the rate adjustment amount ΔQ(t) is calculated by the following formula: ΔQ(t) = α·[P (t) - P(t)] / P (t) +β·ΔP(t), where α is the proportional coefficient, the value is 1.85, and β is the differential coefficient, the value is 0.76. When the pressure reaches 2.85MPa, it enters the pressure holding stage. In the pressure holding stage, the constant pressure variable speed mode is used for control, and the pressure is maintained stable by adjusting the grouting rate. The calculation formula of the rate adjustment amount is converted to: ΔQ(t) = -λ·ΔP(t) - μ·∫ΔP(t)dt, where λ is the proportional coefficient, the value is 2.13, and μ is the integral coefficient, the value is 0.58. When the grouting time reaches 18.3 minutes, it enters the pressure reduction stage. In the pressure reduction stage, the proportional attenuation method is used to reduce the grouting rate, and the rate adjustment amount is calculated according to the exponential attenuation law: ΔQ(t) = Q0·exp(-σt), where Q0 is the initial rate, the value is 1.7L / min, and σ is the attenuation coefficient, the value is 0.237.

[0040] In the control process, the fine adjustment of pressure fluctuation is achieved by combining the diffusion law of slurry. By applying periodic perturbations to the grouting pressure, the diffusion and penetration of slurry in the cracks are promoted. The fluctuation function of the pressure perturbation adopts an improved sinusoidal wave form: ΔP(t) = A·sin(ωt)·exp(-ηt), where A is the fluctuation amplitude, which is 0.15MPa, ω is the angular frequency, which is 0.0327rad / s, and η is the attenuation coefficient, which is 0.0183. In each fluctuation cycle, the fluctuation parameters are dynamically adjusted according to the pressure response characteristics. When the pressure response lags, the fluctuation amplitude is appropriately increased; when the pressure response is ahead, the fluctuation amplitude is appropriately reduced. The adjustment amount of the fluctuation amplitude is calculated by the following formula: ΔA(t) = ξ·[P(t) - P(tT)] / P(t), where ξ is the adjustment coefficient, which is 0.235, and T is the fluctuation period, which is 3.2 minutes. In this way, adaptive regulation of pressure fluctuations is achieved to ensure sufficient diffusion and penetration of the slurry in the coal body cracks.

[0041] At step S104, the grouting area is maintained at a constant temperature and humidity to reduce the drill cuttings desorption value to a target value, which includes: using a constant temperature and humidity maintenance scheme to solidify the grouting area; adjusting environmental parameters by arranging heating plates and spray devices; adjusting the temperature and humidity balance of the maintenance area at preset time intervals; and monitoring the drill cuttings desorption value until it is reduced to below the preset target value.

[0042] In one embodiment, slurry solidification and curing are performed. After the grouting is completed, a constant temperature and humidity curing scheme is adopted. The working surface temperature is maintained at 22.3°C, the relative humidity is maintained at 82.5%, and the continuous curing time is 72 hours. During the curing process, the environmental parameters are adjusted by laying out heating plates and spray devices. The temperature and humidity balance of the curing area is adjusted every 4.5 hours, and the adjustment time is controlled within 8 minutes. During the curing process, when the drill cuttings desorption value drops below 0.46mL / g, the next stage can be entered.

[0043] In step S105, the density of the sealing section, the slurry diffusion radius and the bonding strength of the surrounding rock are measured respectively, and the construction parameters are recorded, including: using the acoustic wave detection method to measure the density of the sealing section; using the drilling coring method to measure the slurry diffusion radius; using the pull-out test to measure the bonding strength with the surrounding rock; recording the construction parameters to establish a construction database.

[0044] Specifically, quality inspection is carried out and multiple inspections are carried out on the grouting effect. The specific inspection contents include: using the ultrasonic detection method to determine the density of the sealing section, which is required to be no less than 0.92; using the drilling coring method to determine the slurry diffusion radius, which is required to be no less than 1.85 meters; using the pull-out test to determine the bonding strength with the surrounding rock, which is required to be no less than 1.26MPa. When all the above indicators meet the requirements, the sealing grouting work can be completed. By recording the actual construction parameters, a construction database is established.

[0045] Figure 2 A three-dimensional surface diagram of the pressure distribution of a grouting hole disclosed in an embodiment of the present application shows a three-dimensional surface of the pressure distribution around the grouting borehole (i.e., at the grouting port of the outer bladder). In this surface, the pressure distribution shows an axisymmetric feature centered on the borehole, which originates from the radial diffusion characteristics of the slurry in the coal body fissures. The maximum pressure value of the surface is 2.85MPa, which is consistent with the pressure in the stable stage described above. The attenuation law of pressure with radial distance conforms to the characteristics of an exponential function, and the pressure value at 1.85 meters drops to 36.8% of the initial value, which is consistent with the minimum diffusion radius requirement specified in the original text. A periodic corrugated structure can be observed on the surface, which reflects the pressure perturbation characteristics of 0.15MPa amplitude and 0.0327rad / s angular frequency during the grouting process.

[0046] By analyzing the pressure distribution surface, the mechanism of action of the double-layer sealing structure can be explained. The inner layer of the bag is mainly used to form a local high-pressure area to promote the penetration of slurry into the deep cracks; the outer layer of the bag controls the diffusion range of the slurry to prevent the slurry from flowing along the borehole wall. The multi-graded coal powder material filled between the two sealing bags has a particle size distribution (0.25-0.5 mm accounts for 37.2%, 0.5-1.0 mm accounts for 42.5%, and 1.0-2.0 mm accounts for 20.3%), forming a gradient permeability structure, which not only ensures the sealing effect, but also does not affect the directional injection of the slurry.

[0047] Figure 3 This is a performance comparison chart of a grouting control method disclosed in an embodiment of the present application, which compares the pressure change characteristics of the adaptive control method and the conventional step-by-step control method. The entire grouting process is divided into three stages: the lifting stage (4.6 minutes), the stabilization stage (18.3 minutes), and the depressurization stage (6.7 minutes). In the lifting stage, both methods use a linear boost method to increase the pressure to 2.85MPa, but the adaptive control method achieves a smoother pressure transition through variable rate climbing. This is due to the synergistic effect of the proportional coefficient α=1.85 and the differential coefficient β=0.76 in the controller.

[0048] In the stable stage, the conventional control method maintains a constant pressure, while the adaptive control method imposes periodic pressure fluctuations. The fluctuation function adopts a modified sine wave form, and the progressive attenuation of the fluctuation amplitude is achieved through the exp(-0.0183t) term. When the pressure response lags, the controller dynamically adjusts the fluctuation amplitude through the adjustment coefficient ξ=0.235 to ensure that the slurry fully penetrates into the coal body cracks. This adaptive fluctuation feature matches the rheological properties of the slurry, in which the apparent viscosity of the slurry (μa=1.73·γ^(-0.14)) changes with the shear rate to reveal the theoretical basis.

[0049] In the depressurization stage, the adaptive control method uses an exponential decay coefficient of σ=0.237 to achieve a smooth drop in pressure, avoiding the sudden pressure change that may occur in the conventional control method. By comparing the curves, it can be observed that the adaptive control method exhibits better dynamic response characteristics throughout the process, which is due to the online learning ability of its five-layer fuzzy neural network structure. The 27 basic rules and Gaussian membership function of the network achieve precise regulation of the grouting rate, where the proportional coefficient of λ=2.13 and the integral coefficient of μ=0.58 ensure the stability of the control.

[0050] From the perspective of engineering implementation, this adaptive control method fully considers the particularity of the underground environment of coal mines. The proportion of grouting materials (62.3% silicate cement, 8.7% composite expansion agent, 0.6% carboxyl water reducer, 0.4% hydroxypropyl methylcellulose stabilizer) ensures that the slurry maintains an appropriate viscosity of 1.85Pa·s at an initial temperature of 16.8℃. Through the calculation of pressure loss during pipeline transportation (P = (8k·L / πR^4)·(3n+1 / 4n)^n·Q^n, where L=28.6 meters and R=0.023 meters), a quantitative relationship between pressure and flow was established, which provided a basis for the selection of control parameters. The final quality acceptance indicators (density not less than 0.92, diffusion radius not less than 1.85 meters, and bonding strength not less than 1.26MPa) verified the reliability of this method.

[0051] Furthermore, an embodiment of the present application also discloses an adaptive control device for underground hole sealing and grouting in coal mines, comprising: a processor, a memory, and a system bus; the processor and the memory are connected via the system bus; the memory is used to store one or more programs, and the one or more programs include instructions, which, when executed by the processor, enable the processor to execute any of the above methods.

[0052] Furthermore, an embodiment of the present application also discloses a computer program product, which, when executed on a terminal device, enables the terminal device to execute any of the above methods.

[0053] It can be known from the description of the above implementation mode that those skilled in the art can clearly understand that all or part of the steps in the above-mentioned embodiment method can be implemented by means of software plus a necessary general hardware platform. Based on such an understanding, the technical solution of the present application can be essentially or partly embodied in the form of a software product that contributes to the prior art. The computer software product can be stored in a storage medium such as ROM / RAM, a disk, an optical disk, etc., including several instructions for enabling a computer device (which can be a personal computer, a server, or a network communication device such as a media gateway, etc.) to execute the methods described in the various embodiments of the present application or certain parts of the embodiments.

[0054] It should be noted that the various embodiments in this specification are described in a progressive manner, and each embodiment focuses on the differences from other embodiments, and the same or similar parts between the various embodiments can be referred to each other. For the device disclosed in the embodiment, since it corresponds to the method disclosed in the embodiment, the description is relatively simple, and the relevant parts can be referred to the method part description.

[0055] It should also be noted that, in this article, relational terms such as first and second, etc. are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Moreover, the terms "include", "comprise" or any other variants thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or device. In the absence of further restrictions, the elements defined by the sentence "comprise a ..." do not exclude the presence of other identical elements in the process, method, article or device including the elements.

[0056] The above description of the disclosed embodiments enables those skilled in the art to implement or use the present application. Various modifications to these embodiments will be apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the present application. Therefore, the present application will not be limited to the embodiments shown herein, but will conform to the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. An adaptive control method for sealing and grouting in underground coal mines, characterized in that: include: Sealing bags are installed in sequence at two drilled sections of the working face in the coal mine and compressed air is injected, and multi-graded coal powder materials are filled in layers in the cylindrical space between the bags and compacted; Ordinary Portland cement, composite expansion agent, carboxyl water reducer, hydroxypropyl methylcellulose stabilizer and water in a preset ratio are mixed and sieved; Implement step-by-step pressure injection, and control the grouting pressure and rate by means of variable rate ramping, constant pressure variable speed, and proportional attenuation. This includes: adopting a step-by-step pressure injection scheme to divide the grouting pressure into three stages for control; establishing a pressure and rate response function to determine the pressure and rate matching range during the grouting process; constructing an adaptive controller based on a fuzzy neural network to dynamically adjust the grouting pressure and rate; promoting the diffusion and penetration of slurry in cracks through periodic pressure perturbations; and dynamically adjusting the fluctuation parameters according to the pressure response characteristics. The grouting area is maintained at a constant temperature and humidity to reduce the drill cuttings desorption value to the target value; The density of the sealing section, the slurry diffusion radius and the bonding strength of the surrounding rock were measured respectively, and the construction parameters were recorded.

2. The adaptive control method according to claim 1, characterized in that: in, Sealing bags are installed in sequence at two drilled sections of the working face in the coal mine and compressed air is injected. The cylindrical space between the bags is filled with multi-graded coal powder materials in layers and compacted, including: Select the grouting area at the working face in the coal mine; An inner sealing bag is installed at a first preset distance from the end of the drill hole, and compressed air of a preset pressure is injected to expand the bag to form a seal; An outer sealing bag is installed at a second preset distance from the end of the drill hole, and compressed air of a preset pressure is injected to expand the bag to form a seal; The cylindrical space between the two plugging bags is filled with multi-graded coal powder material in layers through the grouting holes of the outer plugging bag; The multi-graded coal powder material is filled by a layered filling method and lightly compacted.

3. The adaptive control method according to claim 1, characterized in that: in, Ordinary Portland cement, composite expansion agent, carboxyl water reducer, hydroxypropyl methylcellulose stabilizer and water in a preset ratio are mixed and sieved, including: Cement-based slurry is selected as the base material and modified; Ordinary Portland cement, composite expansion agent, carboxyl water reducer, hydroxypropyl methylcellulose stabilizer and water are mixed according to a preset ratio, and mixed and stirred for a preset time; The viscosity of the slurry is maintained at a preset value by adjusting the stirring speed; The stirred slurry is screened to remove agglomerates.

4. The adaptive control method according to claim 1, characterized in that: in, The grouting area is maintained at a constant temperature and humidity to reduce the desorption value of drill cuttings to the target value, including: Use constant temperature and humidity curing scheme to solidify and cure the grouting area; Adjust environmental parameters by laying out heating plates and spray devices; Adjust the temperature and humidity balance of the maintenance area at preset time intervals; The drill cuttings desorption value is monitored until it drops below a preset target value.

5. The adaptive control method according to claim 1, characterized in that: in, The density of the sealing section, the slurry diffusion radius and the bonding strength of the surrounding rock were measured respectively, and the construction parameters were recorded, including: The density of the sealing section is determined by ultrasonic testing method; The slurry diffusion radius was determined by the drilling and coring method; The bond strength with the surrounding rock was determined by pull-out test; Record construction parameters and establish a construction database.

6. The adaptive control method according to claim 1, characterized in that: in, Dynamically adjust grouting pressure and rate, including: The variable rate ramping method is used to control the pressure increase stage; The constant pressure and variable speed method is used to control the pressure holding stage; The pressure reduction stage is controlled by proportional decay.

7. The adaptive control method according to claim 1, characterized in that: in, Dynamically adjust fluctuation parameters based on pressure response characteristics, including: ， in, Indicates time The pressure perturbation at represents the fluctuation amplitude, represents the angular frequency, Represents the attenuation coefficient.

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