608 results about "Coal pillar" patented technology

A system and a method for monitoring overlying roof rock and coal pillar in gob-side entry are provided. The system includes top monitoring stations, coal pillar comprehensive monitoring stations, roof stress monitoring stations, and a master computer. Top monitoring stations are arranged in the crossheading to monitor the working face, coal pillar comprehensive monitoring stations are arranged in the upper roadway of the lower coal seam working face to monitor the coal pillars, and roof stress monitoring stations are arranged in the mining area main roadway to monitor the coal pillars. Monitoring the stress and deformation distribution of coal pillars in the goaf and the movement and failure process of overburden strata structure through the master computer control each monitoring station. The monitoring stations ensure that the overburden strata movement monitoring stations are still in working condition after the goaf is formed by mining in the working face.

The invention discloses a coal pillar damage dynamic monitoring system and method based on multi-physics coupling and distributed optical fiber sensing, and relates to the technical field of dynamic monitoring. Multi-physics coupling data of a coal pillar is collected in real time through a distributed optical fiber sensing network, and a health index of a coal pillar structure is obtained based on a trained time sequence multi-scale mapping model; the damage evolution rate of the coal pillar is calculated, and if the damage evolution rate is lower than a preset first threshold value, the sampling frequency of the distributed optical fiber sensing network is adjusted, and the data acquisition density of the distributed optical fiber sensing network is reduced; increasing the sampling frequency of the distributed optical fiber sensing network and constructing a trend prediction model to generate evolution prediction of the coal pillar damage if the coal pillar damage is not lower than the preset first threshold value but lower than the preset second threshold value; and if not, switching the distributed optical fiber sensing network to a high-frequency sampling mode, and generating the evolution acceleration of the coal pillar damage. The optimal configuration of the monitoring resources and the dynamic adjustment of the monitoring intensity are realized.

The invention discloses a goaf gas and coal spontaneous combustion composite disaster simulation system and prediction method, and belongs to the technical field of coal mine thermodynamic disaster evolution process simulation tests. The simulation system comprises a transparent cover body, a simulation test bed, a mining working face similar simulation model, a gas supply unit, a monitoring unit, a camera device and a balancing weight. The inclination angle of the base is adjusted by adjusting the telescopic supporting legs, a water bag is used for simulating a coal seam, and a coal pillar serves as a methane release channel in the simulated mining process. A mining process is simulated, gas is conveyed, methane and oxygen concentration data evolution laws are monitored, a related contour map is drawn, interpolation is carried out to reconstruct a space dangerous area, finally, a phase space reconstruction method is adopted to carry out chaos prediction, and disaster space form changes are analyzed. The simulation test and visualization of the evolution process of the gas and coal spontaneous combustion composite disaster can be realized, a dangerous area is quantitatively represented, a theoretical basis is provided for disaster prevention and control, and the energy safety and the life safety of workers are guaranteed.

The invention discloses an extra-thick coal seam narrow coal pillar double-roadway tunneling and entry retaining stability control method. The method comprises the following steps that S1, the roadway position of a first mining working face is determined; tunneling is conducted from the two sides respectively, a first mining working face air return gate way is excavated on one side in a single-roadway tunneling mode, and an asymmetric first mining working face haulage gate way and a first mining working face air inlet gate way are excavated on the other side in a narrow coal pillar retaining double-roadway tunneling mode at the same time; s2, tunneling of a gate way in the first mining working face; s3, in the stoping process of the first mining working face, top cutting pressure relief is conducted on a top plate on an advanced working face of a haulage roadway of the first mining working face, and grouting reinforcement is conducted on a coal pillar plate and a slope transition section coal body on a lagging working face of an air inlet roadway of the first mining working face; and S4, tunneling and stoping of the continuous working face. The lateral confining pressure of the narrow coal pillar is improved through asymmetric arrangement of the two roadways, a structure with the weak upper portion and the strong lower portion is formed to transfer a preferential deformation position to adapt to top plate movement, the coal pillar anchoring environment is optimized, and ultra-thick coal seam narrow coal pillar double-roadway tunneling and entry retaining stable control is achieved.

The invention discloses a method and system for designing the roof cutting height of coal-pillar-free self-forming roadway mining, and belongs to the technical field of coal mining, and the method comprises the following steps: according to the size of a stope, the advancing length of a working face and the thickness of an overlying strata top plate, analyzing the crushing and expanding characteristics of roof cutting caving rock mass through numerical simulation and similar simulation tests; on the basis of the crushing and swelling characteristics of the roof-cutting caving rock mass, the crushing and swelling amount of caving gangue in the bilateral roof-cutting range is calculated; and when the actual mining amount reaches the collapsed gangue crushing and swelling amount, the mining height at the moment serves as the optimal roof cutting height. According to the method, the collapse thickness of the overlying strata can be increased, more broken and expanded gangues are generated, the goaf can be fully filled, the broken and expanded balance of the overlying strata is realized, and the broken and expanded gangues are utilized to compensate the coal seam mining space, slow down the deformation of the overlying strata and relieve the damage to the surface ecological environment.

The invention discloses a mining section coal pillar goaf side concrete wall reinforcing method, and relates to the field of coal mining, and the method comprises the following steps: collecting section coal pillar geological parameters; calculating a boundary position of a plastic zone according to geological parameters of the coal pillar, and dividing the coal pillar into a broken zone, a fractured zone and an original structure zone; basic roof strata are determined according to geological parameters of the coal pillar, the bearing capacity of the basic roof strata is calculated, the basic roof strata with the minimum bearing capacity serves as a roof cutting target layer, and the hydrofracture roof cutting drilling depth needed for penetrating through the target layer is determined; the broken area range serves as the influence range of surrounding rock pressure calculation, the static load q applied to the concrete wall by the surrounding rock pressure is calculated, the static load q is corrected through a dynamic load coefficient, and a supporting load Q is obtained; and according to the support load Q, reinforcement parameters are determined. Aiming at the surrounding rock deformation and instability of the adjacent roadway on the section coal pillar gob side under the deep well mining condition, the method effectively controls the surrounding rock deformation and instability of the adjacent roadway caused by working face mining disturbance.

The invention relates to the field of coal mine tunnel deformation control, in particular to a coal mine tunnel floor heave prevention and treatment method based on bottom plate blasting pressure relief, which comprises the following steps: S1, determining a coal seam side support pressure curve and a coal pillar or entry retaining filling body side support pressure curve of a mining tunnel; the Rankine soil pressure theory is introduced to analyze the stress characteristics of a bottom plate of the mining roadway, and the coal seam side sliding body range and the coal pillar or entry retaining filling body side sliding body range are determined; s2, determining a blasting pressure relief rock stratum in the bottom plate; s3, determining a blasting pressure relief range; and S4, blasting is conducted on the determined blasting pressure relief range through blasting pressure relief drill holes. According to the method, the blasting pressure relief area is selected from the thick and hard coal seam bottom plate and is close to the sliding body, and floor heave prevention and control can be carried out on the basis of constructing the blasting pressure relief area in the minimum range; meanwhile, after the Rankine soil pressure theory is introduced to determine the slippage body, the reasonable blasting pressure relief area range is determined based on the slippage body and the supporting pressure.

The invention provides a method for analyzing the dynamic stability of a slope containing a mining cavern group under the action of dynamic and static loads, and belongs to the technical field of analysis of the dynamic stability of the slope containing the mining cavern group. In order to solve the technical problem that complex mechanical behaviors of a slope containing a mining cave group under the dynamic and static load coupling effect are difficult to accurately consider because most of existing slope stability analysis aims at single static load or dynamic load working conditions, the technical scheme adopted by the invention comprises the following steps: collecting end slope mining coal pillars and rock samples of rock stratums overlying the end slope mining coal pillars, and testing physical and mechanical parameters of the rock samples; the physical and mechanical parameters of all the rock stratums are finally selected in combination with related production materials of the mining area; calculating a shear strength parameter of the rock mass after the rock is damaged under the action of cyclic blasting vibration; calculating shear strength parameters of the end slope mining area-evolved weak layer under the action of blasting vibration; the stability of the slope containing the mining cavern group under the blasting vibration effect is calculated; the method is applied to the stability analysis of the power of the slope containing the mining cavern group.

The invention provides a coal pillar dam body safety monitoring method and device based on a sounding event and a microseismic event, and the method comprises the steps: carrying out a mechanical test through environment simulation, obtaining a voiceprint feature signal in a fracture evolution process through an acoustic emission monitoring technology, analyzing and determining a percolation threshold value, and constructing a percolation model; training a percolation prediction model based on the voiceprint feature signal, the fracture evolution process and the percolation model; acquiring micro-seismic data by using a micro-seismic sensor and determining micro-seismic event distribution to obtain a micro-seismic characteristic signal; inputting the microseismic characteristic signal into a percolation prediction model to obtain a target percolation model and a target stress state, and performing safety level evaluation; and when the evaluation result shows that the safety level is low, grouting reinforcement is conducted on fracture cluster communication points of the coal pillar dam body according to the target percolation model. The method solves the problems that in the prior art, a coal pillar dam body safety monitoring method adopts multiple types of equipment, safety level analysis conditions are complex, and feedback delay is caused.

The invention discloses a visual three-dimensional test device for grouting reinforcement and effect of a mine boundary coal pillar under a thin unconsolidated formation, and relates to the technical field of similar test simulation equipment for grouting reinforcement of the mine coal pillar. The device comprises a test support, an internal frame, a model storage box, a loading plate assembly, a model cutting mechanism, a vertical loading mechanism, a horizontal loading mechanism, a signal acquisition and processing mechanism, a three-dimensional test model, a coal mining simulation mechanism, a model grouting mechanism, a model separation mechanism and an effect visualization mechanism. According to the coal seam mining simulation mechanism, step-by-step, segmented and controllable excavation of a three-dimensional similar model in a closed space can be achieved, generation, expansion and penetration of coal seam mining roof rock stratum cracks are inverted, and the evolution process of a water guide channel is finally formed. According to the invention, the diffusion and runout characteristics of the grouting reinforcement slurry for the boundary coal pillar of the mine under the thin unconsolidated formation can be truly simulated, and the dynamic process of diffusion, condensation and reinforcement of the coal pillar by the slurry in the water-guiding damage fracture can be reproduced.

The invention belongs to the technical field of coal mine safety monitoring, and relates to a digital twinning efficient virtual-real synchronization method of inter-face coal pillar digging and supporting integrated equipment. Comprising the following steps: step 1, lightening a digital twin three-dimensional model of the equipment; 2, establishing an equipment digital twin motion behavior model; step 3, establishing an equipment trajectory prediction model: predicting the twinborn body posture of the tunneling and supporting equipment based on Self-Attention-LSTM (Long Short Term Memory); step 4, establishing a virtual space equipment driving and correction model, and a digital twin platform dynamic updating method based on pose correction of a quadratic spline interpolation method and state synchronization; and 5, associating the models to establish virtual-real synchronous interaction of the digital twin tunneling and supporting equipment. The method combines compressed twinning three-dimensional model data and a trajectory prediction model to reduce the driving data volume required by a digital twinning system, more efficiently drives the movement of virtual space equipment, can stably work under the conditions that sensing data is difficult to obtain and data communication is limited, and has higher reliability and practicability.

The invention discloses a gob-side coal pillar spraying device for preventing spontaneous combustion of coal and a using method of the gob-side coal pillar spraying device, and belongs to the technical field of mining equipment.The spraying device comprises a first spraying assembly, a detection assembly and a second spraying assembly, and the first spraying assembly is used for spraying for the first time; the detection assembly is used for detecting the thickness and / or uniformity of the first spraying; the second spraying assembly is used for conducting second-time spraying, and the spraying amount and / or the spraying speed of the second-time spraying are / is adjusted according to the detection result of the detection assembly. The detection assembly is used for detecting the spraying condition of the first spraying assembly, the second spraying assembly is used for conducting spraying on the position with the poor spraying effect, the using amount of coal mine air leakage stopping materials can be reduced compared with two-time complete spraying, and the spraying efficiency can be improved compared with manual spraying on the basis that the spraying efficiency is improved. And the spraying uniformity is guaranteed, and the spraying quality is improved.

The invention discloses a continuous mining and continuous filling recovery section coal pillar mining method and system, and the method comprises the steps: determining the position of a coal pillar working face crossheading, and carrying out gob-side entry driving along the positions, close to goaf, of the two sides of a coal pillar; grouting and plugging the goaf before tunneling, and injecting a flame retardant; side filling roadway forming is conducted on the goaf through coal gangue, and a supporting system of a coal pillar working face crossheading is constructed; supporting a coal pillar working face crossheading; the section coal pillars are recovered by adopting a continuous mining and continuous filling process, and coal bodies are replaced by filling bodies, so that the whole coal pillar recovery-filling process is ensured to be smoothly carried out until all coal resources are recovered. According to the method, the coal recovery rate can be increased, the problems of spontaneous combustion danger and toxic and harmful gas over-limit caused by goaf air leakage are solved, the fire hazard caused by sparks generated when a fully-mechanized coal winning machine touches old roadway anchor rods in the roadway tunneling process is solved by injecting the flame retardant, waste coal gangue can be effectively utilized, the problems of environmental pollution and the like are avoided, green mining is achieved, and the method is suitable for large-scale popularization and application. The mine service life is prolonged.

The invention relates to the technical field of coal mine intellectualization, and provides an inter-face coal pillar digging and mining robot which comprises a right-angle turning scraper conveyor and a digging and mining robot body. The digging and mining robot is mounted on the right-angle turning scraper conveyor; the digging and mining robot comprises a cutting system, and the cutting system is located on a machine body of the digging and mining robot. Wherein the cutting system is driven by the electric cylinder to move, and vertical cutting of a rectangular section is completed through compound movement of the feeding electric cylinder and the height adjusting electric cylinder; after the cutting action is completed, a walking system of the digging and mining robot moves by one cut width along the right-angle turning scraper conveyor, and the actions are repeated until the whole section is pushed by one cut distance; wherein in the cutting process, the fallen coal is transferred into the right-angle turning scraper conveyor; the stability of the cutting system in the cutting and walking process is ensured through the anti-overturning effect of the guide sliding shoes in the walking system of the digging and mining robot and the force effect of the hydraulic support matched with the right-angle turning scraper conveyor.

The invention provides a method for determining advanced controllable roof cutting parameters of a thick and hard roof of a coal mine stope face, which comprises the steps of engineering general situation field investigation and survey, in-situ geomechanical test, goaf roof thickness / thin plate theoretical analysis, coal pillar or filling body vertical load theoretical analysis, numerical simulation calculation and engineering test verification. Analyzing the mechanical behavior of the working face roof based on a plate theory, verifying the correctness of a theoretical model through measured data, and changing boundary conditions to predict the mechanical behavior of the roof after roof cutting; the method comprises the following steps: analyzing the vertical load of a coal pillar or a roadside support body after roof cutting and the influence rule of roof cutting height and angle on the roadside support body through a mechanical model, and preliminarily obtaining better roof cutting parameters; by establishing a numerical model of different topping parameter combinations, different performance parameters are used for comparing and evaluating different topping parameters, so that the optimal topping parameter is determined; according to the method, advanced controllable roof cutting of the hard roof of the coal seam is achieved, and the mine pressure treatment effect in mining is predicted.

The invention discloses a pre-filling replacement section coal pillar double-roadway-reserved coal mining method which comprises the following steps: arranging a transportation uphill and a rail uphill in a coal seam along the inclination direction, pre-digging a transportation gate road and a rail gate road in the coal seam, forming a filling working face after the two gate roads are communicated, and simultaneously arranging the two filling working faces to carry out advancing type stoping, and solid waste material cemented filling is conducted on the goaf of the filling working face, after stoping filling of the two filling working faces is finished, a long-wall working face is formed by penetrating through the two adjacent crossheading of the two filling working faces, and retreating type stoping is conducted. A traditional section protection coal pillar is omitted, and the coal recovery rate is increased; meanwhile, resource utilization of the coal-based solid waste is achieved, and the problems of land resource waste and environmental pollution are solved.

The invention discloses a grouting and filling method for a cross-layer area of a coal pillar group in a residual mining area, and relates to the technical field of coal mining, which comprises the following steps of: (1) selecting a key layer; (2) a drill hole is constructed in the key layer, a directional initial crack is formed in the drill hole through frosted water jet cutting, then the two ends of the drill hole are set, and the initial crack is expanded to form a crack network in the mode that high-pressure fluid is injected into a hole sealing section; (3) grouting materials are adopted for conducting segmented grouting construction on the drill holes in the step (2), specifically, firstly, low-viscosity grout is used for filling a crack network formed through fracturing, then medium-viscosity grout is used for filling a coal pillar plastic area influenced by mining, and finally high-viscosity grout added with an accelerating agent is used for filling roof fractured rock mass and goaf and goaf roadways; and (4) after the slurry is solidified, a coal pillar-slurry vein body-overlying strata composite bearing structure is formed. According to the invention, the rock mass cohesive force and overall strength of the re-mining area can be obviously enhanced, and the stability of re-mining roadways and working face surrounding rocks is improved.

The invention discloses a grouting reinforcement anti-seepage method for a dam body of a coal mine underground reservoir, which comprises the following steps of: constructing a grouting hole at an artificial dam body position of a dam body to be treated, and performing segmented grouting on the grouting hole; the grouting materials are spread to the interiors of the artificial dam bodies, the interiors of the coal pillar dam bodies, the connecting positions between the artificial dam bodies and the coal pillar dam bodies, the connecting positions between the artificial dam bodies and the top plate rock stratum and the connecting positions between the artificial dam bodies and the bottom plate rock stratum; therefore, micropore cracks in the to-be-treated dam body and the connecting positions between the to-be-treated dam body and the top plate rock stratum and between the to-be-treated dam body and the bottom plate rock stratum can be effectively blocked, the leakproofness and the anti-seepage performance of the coal mine underground reservoir dam body are remarkably improved, and effective anti-seepage reinforcement of the coal mine underground reservoir dam body is achieved.

A method for recovery of residual coal pillars by freezing accumulated water in room-and-pillar mining areas is provided. A feasibility of repeated mining of residual coal pillars in room-and-pillar goafs is distinguished based on production data and exploration data of a mine. An accumulated water in the room-and-pillar mining areas is frozen to replace a paste filling material, which envelopes collapse roofs and gangues in the room-and-pillar goaf as a whole. The room-and-pillar goaf is filled with a frozen ice body. Roadways and mining faces are arranged in the frozen ice body. Coal cutter cuts the residual coal pillars and the frozen ice body. With the advancing of the mining face, the residual coal pillars are gradually recovered and melted water after the cutting is pumped out.

The present invention discloses a combined filling mining method based on original magnesium slag and modified magnesium slag, including the steps of: 1. dividing a plurality of vertical strip coal pillars along the extension direction of the coal seam; 2. mining a plurality of vertical strip coal pillars at intervals, and forming an interval filling area after the strip coal pillars are mined; 3. preparing original magnesium slag-based filling materials and modified magnesium slag-based filling materials; 4. determining the spatial size of the filling area; 5. calculating the filling height of the original magnesium slag-based filling body and the modified magnesium slag-based filling body; 6. filling the filling area with the modified magnesium slag-based filling material; 7. filling the filling area with the original magnesium slag-based filling material to form an interval filling support body; 8. mining the strip coal pillars between adjacent filling supports. The method of the present invention has simple steps, can be effectively applied in combined filling mining, improves the safety of mining, and realizes the resource utilization of two major industrial solid wastes, coal gasification slag and optimized magnesium slag, with significant effects and easy promotion.

The invention discloses a stable anchoring design method for a near-distance coal seam narrow coal pillar gob-side tunneling roadway, and the method comprises the steps: S10, analyzing mining geological conditions, and testing physical and mechanical parameters of coal rock; s11, calculating the width of a plastic zone in a coal pillar after adjacent working faces are mined according to a coal rock physical and mechanical parameter test result, and carrying out numerical simulation calculation on vertical stress distribution of surrounding rock after stoping of the working faces around the gob-side tunneling roadway, and S12, determining the reserved size of the narrow coal pillar according to the content and comprehensive consideration of the anchoring quality of roadway anchor rods and cables. The design method for forming the stable anchoring structure comprises the steps that S20, roadway surrounding rock shear expansion pressure is calculated, S21, the roadway surrounding rock shear expansion pressure is introduced to conduct single end anchor rod action mechanical model derivation, S22, roadway anchor rod cable prestress calculation is conducted according to the result, and S23, the anchor net supporting opportunity is determined.

A mixed feed efficient mining method includes the steps that firstly, an air way, a machine way and a cutting hole are formed, a coal pillar is reserved at the left end of a working face, the length of the reserved coal pillar is larger than that of a single-drum coal mining machine, a machine nest is formed in the right side of the reserved coal pillar, and the length of the machine nest is not smaller than the sum of the length of a double-drum coal mining machine and the length of beveling feed; the single-drum coal mining machines are arranged in the roadways at the two ends of the fully mechanized coal mining face, the double-drum coal mining machines are arranged on the scraper conveyor at the machine nest section, when the double-drum coal mining machines run to be close to the left end or the right end of the fully mechanized coal mining face, reverse beveling feeding is directly carried out for next coal cutting, and it is not needed that coal is cut back and forth after conventional beveling feeding is carried out; coal pillars left at the two ends of the working face are cut by the two-end single-drum coal mining machine through vertical feeding, coal mining at the two ends and the middle section of the working face is achieved at the same time, the mining efficiency is greatly improved, the number of arranged working faces is reduced, the labor time of workers is shortened, and the economic benefits of enterprises are increased.

The invention discloses a coal-pillar-free self-formed roadway intelligent design method and system based on machine learning, and relates to the technical field of coal mining, and the method comprises the following steps: S1, building a 110 construction method intelligent design platform; s2, building a surrounding rock geomechanical model, and monitoring surrounding rock deformation and pressure change in the model; s3, the surrounding rock stability and rock goaf breaking and swelling sufficient filling are judged, and decisions such as support parameters and equipment type selection are completed; s4, establishing a working face digital model; s5, anchor-cutting-support-protection-control integrated self-adaptive collaborative intelligent control is formed through a robot cluster, and analysis is carried out through a working face digital platform; and S6, performing optimization to form a decision optimal model of intelligent coal mining of the 110 construction method. According to the intelligent design method and system for the coal-pillar-free self-forming roadway based on machine learning, the labor cost, the equipment investment and the material consumption are reduced, the total construction cost is reduced, and innovation and development of the underground engineering technology in China are promoted.

The invention discloses a key layer presplitting settlement control method based on overlying strata fracture angle arrangement. The method comprises the steps that geological mining parameters of a target mine are collected and determined; based on the physical and mechanical parameters of each rock stratum, determining the horizon height of the key stratum in combination with a thick and hard rock stratum judgment criterion; according to coal seam mining parameters and overlying strata lithology, the height of a water flowing fractured zone is judged, and high and low horizon classification is conducted on the water flowing fractured zone by combining the horizon of the key horizon; according to the development law of overlying strata damage along the fracture angle from bottom to top, the presplitting position in the horizontal direction of each layer key layer in the presplitting range is calculated and determined, and full-section directional presplitting cutting is carried out; based on thick and hard rock stratum mining-induced stress distribution characteristics and a damage deformation transmission mechanism, a working face moving boundary and a reduction distance of a building (structure) protection coal pillar after key stratum presplitting are calculated and determined. According to the method, presplitting implementation is guided based on the key layer fracture rule, and a new technical approach is provided for subsidence control of the mining area.

The invention provides an underground mining, selecting and filling integrated coal gangue filling and replacing section coal pillar method, and relates to the technical field of coal stoping, and the method comprises the following steps: respectively forming a transportation crossheading and an air return crossheading on the left side and the right side of a section coal pillar, and communicating the transportation crossheading with the air return crossheading through a crossheading connection roadway; and according to the serial number sequence, the strips with the serial numbers being even numbers are subjected to stoping and filling in sequence, and then the strips with the serial numbers being odd numbers are subjected to stoping and filling. An odd-even sectional type stoping method is adopted for the section coal pillars, after stoping, filling slurry is used for preparing a chamber to sort coarse coal and coal gangue, the coal gangue is made into coal gangue filling slurry to be filled into the goaf of the section coal pillars, integrated operation of stoping, sorting and filling is achieved, the method can be suitable for an underground stoping area with multiple working faces, coal pillar resources are efficiently recycled, and the mining efficiency is improved. The method has a good application prospect and a wide application range.

The invention relates to the technical field of mining engineering, in particular to an extra-thick coal seam fully mechanized caving face bearing pressure distribution simulation analysis method which comprises the steps of S1, bearing stability analysis; s2, crack analysis; s3, analyzing the influence of the topping operation; s4, evaluating feasibility of roof cutting roadway protection; according to the method, the stress data of the coal pillar are collected and analyzed to obtain the bearing stability of the coal pillar, the crack propagation speed is analyzed through image acquisition, so that the crack severity degree of the top plate is obtained, and the effect evaluation coefficient of the coal seam roof cutting operation is obtained according to the pressure parameter analysis of the coal seam working face after the roof cutting operation. The roadway deformation amount and the surrounding rock stability are obtained through video recording analysis, and then the feasibility of roof cutting roadway protection is obtained through analysis, so that the coal seam fully mechanized caving face bearing pressure influence evaluation index is comprehensively analyzed, targeted measures can be better taken to guarantee operation safety, the mining technology and process can be optimized, and the mining efficiency is improved.

The invention relates to a goaf remaining coal pillar anti-impact safety level determination method, which comprises the steps of calculating a damage variable D, triaxial strength R and a maximum principal stress sigma 1 value of a remaining coal pillar based on petrology physical parameters and crustal stress parameters of the remaining coal pillar, and determining the anti-impact safety level of the remaining coal pillar based on the damage variable D, the triaxial strength R and the maximum principal stress sigma 1 value, calculating a static stability coefficient k1 of the left coal pillar; calculating a dynamic stability coefficient k2 of the remaining coal pillar based on the size and range Se of the elastic region of the remaining coal pillar and the average stress sigma e and yield stress sigma y values of the elastic region; and based on the static stability coefficient k1 and the dynamic stability coefficient k2 of the remaining coal pillar, determining a safety level result, and taking corresponding safety protection measures according to the safety level result. According to the method, the anti-impact safety level of the goaf remaining coal pillar in the rock burst coal seam mining process is evaluated.

The invention relates to the field of coal mine tunnel design, in particular to a method for cooperatively optimizing the width of a section coal pillar through undercut pressure relief and bottom plate filling. Comprising the steps of determining shear stress distribution in a first mining working face section coal pillar lower bottom plate; determining previous collapse positions of the basic roof; stoping and constructing a bottom cutting drilling hole in a maximum shear stress area in a lower bottom plate of the section coal pillar from the haulage roadway; lagging undercut pressure relief work is conducted, and bottom plate filling drilling is conducted from the track roadway to the position below the undercut pressure relief position at intervals; and grouting is conducted on the bottom plate rock stratum through the filling drill holes. According to the method, the bottom cutting drilling is constructed in the maximum shear stress area, so that the concentration of the shear stress of the bottom plate at the lower part of the section coal pillar is effectively reduced, and the stress of the section coal pillar is reduced. And furthermore, rock blocks at the bottom plate pressure relief position are upwards supported through bottom plate separation layer grouting filling at the lower part of the bottom cutting pressure relief position to prop against a cantilever structure formed by caving of the bottom plate, so that the overlying rock stress borne by the section coal pillar is shared, and the reserved width of the section coal pillar can be reduced.

The invention discloses a method and system for evaluating the influence of working face mining on adjacent large fault stability, and belongs to the field of coal mine safety mining. The method for evaluating the influence of working face mining on the stability of the adjacent large fault comprises the steps that a goaf-protective coal pillar-fault overburden strata space structure model is constructed, and external bearing stress borne by the protective coal pillar after working face mining is conducted is classified; comprise self-weight stress, lateral bearing stress transferred by overlying strata in a goaf and fault concentrated stress formed by a large fault; quantitative analysis is carried out on the lateral bearing stress of the goaf and the fault concentrated stress, and the average external bearing stress borne by the protective coal pillar after the working face is mined out is calculated; carrying out quantitative analysis on the internal bearing strength of the protective coal pillar, and calculating the average value of the internal bearing strength of the protective coal pillar; and evaluating the stability of the protective coal pillar based on the average external bearing stress borne by the protective coal pillar after the working face is mined out and the average value of the internal bearing strength of the protective coal pillar.

The invention relates to the technical field of coal mining and mine safety engineering, and discloses a coal pillar stability dynamic monitoring and pressure relief control method for gob-side entry driving, which comprises the following steps: collecting multi-field coupling signals of a coal pillar, and collecting environmental data of a roadway; analyzing the stability of the coal pillar according to the multi-field coupling signal, and when an analysis result does not meet a stable condition and the environmental data does not meet an environmental condition, generating a cooperative control instruction of the high-pressure water jet system integrated with the solid-liquid waste collection device; executing directional hydraulic fracturing pressure relief operation on the coal pillar area according to the cooperative control instruction, and monitoring the stress distribution and fracture closing state of the coal pillar after pressure relief; hydraulic parameters of the high-pressure water jet system are adjusted according to the coal pillar stress distribution and the fracture closed state; and when the coal pillar recovers the stable state and the environmental data meet the environmental conditions, controlling the pressure relief operation of the coal pillar area according to the cooperative stop instruction. According to the method, the accuracy of dynamic monitoring and pressure relief control of the stability of the coal pillar of gob-side entry driving can be improved.