CN106223931B - System and method for monitoring reserved coal pillar gob-side entry retaining floor crack development - Google Patents
System and method for monitoring reserved coal pillar gob-side entry retaining floor crack development Download PDFInfo
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- CN106223931B CN106223931B CN201610789375.XA CN201610789375A CN106223931B CN 106223931 B CN106223931 B CN 106223931B CN 201610789375 A CN201610789375 A CN 201610789375A CN 106223931 B CN106223931 B CN 106223931B
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- E—FIXED CONSTRUCTIONS
- E21—EARTH DRILLING; MINING
- E21B—EARTH DRILLING, e.g. DEEP DRILLING; OBTAINING OIL, GAS, WATER, SOLUBLE OR MELTABLE MATERIALS OR A SLURRY OF MINERALS FROM WELLS
- E21B47/00—Survey of boreholes or wells
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- C—CHEMISTRY; METALLURGY
- C04—CEMENTS; CONCRETE; ARTIFICIAL STONE; CERAMICS; REFRACTORIES
- C04B—LIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE; CERAMICS; REFRACTORIES; TREATMENT OF NATURAL STONE
- C04B28/00—Compositions of mortars, concrete or artificial stone, containing inorganic binders or the reaction product of an inorganic and an organic binder, e.g. polycarboxylate cements
- C04B28/02—Compositions of mortars, concrete or artificial stone, containing inorganic binders or the reaction product of an inorganic and an organic binder, e.g. polycarboxylate cements containing hydraulic cements other than calcium sulfates
- C04B28/04—Portland cements
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- C—CHEMISTRY; METALLURGY
- C04—CEMENTS; CONCRETE; ARTIFICIAL STONE; CERAMICS; REFRACTORIES
- C04B—LIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE; CERAMICS; REFRACTORIES; TREATMENT OF NATURAL STONE
- C04B28/00—Compositions of mortars, concrete or artificial stone, containing inorganic binders or the reaction product of an inorganic and an organic binder, e.g. polycarboxylate cements
- C04B28/02—Compositions of mortars, concrete or artificial stone, containing inorganic binders or the reaction product of an inorganic and an organic binder, e.g. polycarboxylate cements containing hydraulic cements other than calcium sulfates
- C04B28/06—Aluminous cements
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- E—FIXED CONSTRUCTIONS
- E21—EARTH DRILLING; MINING
- E21B—EARTH DRILLING, e.g. DEEP DRILLING; OBTAINING OIL, GAS, WATER, SOLUBLE OR MELTABLE MATERIALS OR A SLURRY OF MINERALS FROM WELLS
- E21B33/00—Sealing or packing boreholes or wells
- E21B33/10—Sealing or packing boreholes or wells in the borehole
- E21B33/13—Methods or devices for cementing, for plugging holes, crevices, or the like
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- E—FIXED CONSTRUCTIONS
- E21—EARTH DRILLING; MINING
- E21B—EARTH DRILLING, e.g. DEEP DRILLING; OBTAINING OIL, GAS, WATER, SOLUBLE OR MELTABLE MATERIALS OR A SLURRY OF MINERALS FROM WELLS
- E21B47/00—Survey of boreholes or wells
- E21B47/002—Survey of boreholes or wells by visual inspection
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- C—CHEMISTRY; METALLURGY
- C04—CEMENTS; CONCRETE; ARTIFICIAL STONE; CERAMICS; REFRACTORIES
- C04B—LIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE; CERAMICS; REFRACTORIES; TREATMENT OF NATURAL STONE
- C04B2111/00—Mortars, concrete or artificial stone or mixtures to prepare them, characterised by specific function, property or use
- C04B2111/00474—Uses not provided for elsewhere in C04B2111/00
- C04B2111/00724—Uses not provided for elsewhere in C04B2111/00 in mining operations, e.g. for backfilling; in making tunnels or galleries
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- C—CHEMISTRY; METALLURGY
- C04—CEMENTS; CONCRETE; ARTIFICIAL STONE; CERAMICS; REFRACTORIES
- C04B—LIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE; CERAMICS; REFRACTORIES; TREATMENT OF NATURAL STONE
- C04B2111/00—Mortars, concrete or artificial stone or mixtures to prepare them, characterised by specific function, property or use
- C04B2111/70—Grouts, e.g. injection mixtures for cables for prestressed concrete
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- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02W—CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO WASTEWATER TREATMENT OR WASTE MANAGEMENT
- Y02W30/00—Technologies for solid waste management
- Y02W30/50—Reuse, recycling or recovery technologies
- Y02W30/91—Use of waste materials as fillers for mortars or concrete
Abstract
The invention discloses a system and a method for monitoring reserved coal pillar gob-side entry retaining bottom plate crack development, wherein a bottom plate drilling field is cut on one side of the reserved coal pillar gob-side entry retaining, drilling holes with different depths are constructed on the bottom plate, and a butt joint sealing system is adopted to butt-joint transparent hollow pipes section by section into the drilling holes; and after grouting and anchoring the gap between the drilling hole and the transparent hollow pipe, recording the surrounding rock cracks of the drilling holes at different positions on the measuring scale by utilizing the detection positioning assembly, and carrying out the evolution monitoring task of the mining failure rule of the bottom plate for multiple times at different mining stages until the data tend to be stable and finish observation. According to the invention, the bottom plate shallow drilling holes, the bottom plate middle deep drilling holes and the bottom plate deep drilling holes which are arranged side by side extend from the drilling site to the bottom plate direction of the coal seam to be mined are arranged in a three-dimensional manner, and the development forms of the plastic damage areas of the bottom plate in mining and the development forms of the damage areas of the bottom plate after coal seam mining can be defined by observing the conditions of the adjacent drilling holes at the same time and the cracks of the same drilling hole in different coal mining stages, so that reliable data reference is provided for safe construction.
Description
Technical Field
The invention relates to a system and a method for monitoring the development of reserved coal pillar gob-side entry retaining floor cracks, and belongs to the field of mine support.
Background
The coal resource distribution in China has strong regionality, about 90% of the coal resources are produced from North China coal fields at present, the severe mine water damage form always seriously influences the coal mine safety production in China, the stable and healthy development of national economy is restricted, and the coal field development has important significance for the national economy development. Meanwhile, many coal fields in China are very complex in hydrogeological conditions, the coal mining process is threatened by various water bodies, only the main mining areas in the north are threatened by karst water, the coal reserves are about 150 hundred million tons, 27% of the detected reserves are occupied, in the water bursting form of all water damage accidents, the water damage of the particularly outstanding coal seam bottom plate is 88.1%, and the coal mine production safety is seriously threatened. Therefore, the method has the advantages that the method is used for deeply developing the mechanism of the under-pressure mining face floor to damage the water inrush and the research of an early warning system, effectively restraining the occurrence of mine water inrush accidents and guaranteeing the safe production of coal mines, is a problem which needs to be solved by the coal industry of China at present, has great significance for further improving the production effect and the resource recovery rate of large water mining areas, and also provides a scientific and reliable reference for the safe and efficient mining of the coal beds of the same type in the future.
Through years of on-site practical observation of the bottom plate mining, it is widely considered that the mining coal seam bottom plate can be divided into a lower three zones from the bottom surface of the coal seam to the top surface of the water-bearing layer like an overburden layer, namely a bottom plate water-guiding damage zone, a complete stratum zone and a pressure-bearing water lifting zone. The theory of 'lower three zones' accords with the coal seam floor damage and water burst rule, and is widely applied in production practice, so that the on-site observation of the floor water guide damage zone has important significance. In order to find out the deformation and damage rule of the bottom plate, the research methods adopted at present can adopt theoretical research, numerical simulation research, experimental research and the like, and although the methods play an important role in recognizing the movement and deformation rule of the bottom plate rock stratum, in engineering practice, the method for deducing the movement and deformation and damage rule of the bottom plate rock stratum by utilizing measured data information is definitely the most direct and reliable method.
The current on-site observation method comprises the following steps: drilling sound wave test method, bottom plate drilling displacement meter method, drilling peeping test method, drilling stress meter, drilling water discharge method, etc. The drilling acoustic wave test method is to observe the development rule of mining fracture of the rock mass before and after mining and the depth of the mining fracture; (2) the base plate drilling displacement meter method is to set displacement observation base points in the drilling holes to observe the displacement change rule of the base plates before and after mining; (3) the drilling peeping test method is used for observing macroscopic change of the bottom plate rock mass fracture during the stoping of the working face; (4) the drilling stress meter acquires stress strain data of the bottom plate rock stratum by collecting the mechanical property change of the bottom plate rock stratum, and analyzes the damage condition of the bottom plate; (5) by using a drilling water drainage method, inclined holes with a certain depth are drilled on a coal seam bottom plate before mining, the outward water flow rate in unit time is observed every day, and when water does not flow outwards, the inward water injection rate in unit time is observed every day, and the damage depth of the coal seam bottom plate caused by mining influence can be known through the comprehensive analysis of the water drainage rate change in unit time and hydrogeological conditions of different depth drilling holes in the mining process. Among the above methods, only the borehole peeping test method belongs to a method for directly observing the evolution rule of surrounding rock, and has higher credibility and authenticity, but the following problems often exist in the actual operation and monitoring process of the borehole peeping test method:
(1) When coal mining of coal seam in China, the gob-side entry retaining is adopted to re-support and retain the gob-side entry of the previous section for the next section, so that resources can be recovered to the greatest extent by the gob-side entry retaining, coal loss is avoided, and the gob-side entry retaining is divided into a gob-side entry retaining of a reserved section coal pillar and a gob-side entry retaining of a non-coal pillar. In both cases, the gob-side entry retaining can cause hole collapse of the drilling hole of the shallow bottom plate, even if the wall protection sleeve with a certain depth is put in, the hole collapse phenomenon of the monitoring section (without the wall protection sleeve) still exists, once the hole collapse occurs, the hole is difficult to repair again, the only method is to repair the drilling hole again, time and labor are wasted, and the best observation time is more likely to be missed;
(2) The coal seam floor rock stratum is generally divided into a hard rock stratum, a soft rock stratum and a soft and hard alternate rock stratum, if the soft rock stratum or the soft and hard alternate rock stratum is encountered during the drilling of the construction floor, particularly in a drilling monitoring section of the floor, the soft rock has the softening effect when meeting water, for example, if data are not observed in time, the drilling soft rock section can be automatically closed or collapsed in a short time, so that the drilling is invalid, the drilling is required to be repeated, and even the drilling is repeated, so that the monitoring cost is greatly increased; meanwhile, the frequent replacement of the drill hole has the consequences that available data cannot be effectively collected, macroscopic changes of cracks at the same position and different time periods are not compared with each other, and the reliability of detection results is low.
(3) Even if the initial drilling peeping data can be observed smoothly before coal seam exploitation, as the coal face is continuously pushed, the bottom plate is mechanically changed due to the action of the supporting pressure of the coal pillar to cause the bottom plate rock stratum to be broken, so that the conventional naked hole uses the drilling peeping instrument to cause the conditions of clamping, clamping a camera and the like, even the camera shooting observation equipment can be damaged, and certain economic loss is brought.
(4) During observation, a great amount of muddy water, sewage, suspended matters in oil-water mixture and air bubbles in water exist in the drill hole frequently, even if the drill hole is continuously flushed by matching with water injection of the drill hole, effective data cannot be collected, the definition and the authenticity of observation are greatly affected, a rough conclusion can be obtained only through a great amount of calculation and evaluation after the data are obtained, whether the conclusion is reliable or not cannot be ensured, namely the position and the development condition of rock stratum change cannot be obtained quickly and accurately, and great potential safety hazards are brought to subsequent normal construction.
Disclosure of Invention
Aiming at the problems existing in the prior art, the invention aims to provide a drilling device capable of improving the drilling failure rate and reducing the economic loss; the safe use of the drilling peeping device and the normal detection process can be ensured; the system and the method can rapidly and accurately obtain the rock stratum fracture change condition and development condition, always keep the drilling at the optimal effect of anhydrous observation, and can meet the requirement of repeated use for a plurality of times and ensure the reliable data of monitoring the reserved coal pillar gob-side entry retaining floor fracture development.
In order to achieve the above purpose, the invention adopts the following technical scheme: the system for monitoring the development of the reserved coal pillar gob-side entry retaining bottom plate cracks comprises a gob-side entry retaining and a lower gate in parallel, wherein a section coal pillar is reserved between the gob-side entry retaining and the lower gate, a coal mining layer is arranged on the other side of the lower gate, a bottom plate drilling hole is arranged on one side of the gob-side entry retaining close to an adjacent coal mining surface, a bottom plate shallow drilling hole, a bottom plate middle deep drilling hole and a bottom plate deep drilling hole are arranged in an extending manner from the bottom plate drilling hole to the bottom plate direction of the coal mining layer, the bottom plate shallow drilling hole, the bottom plate middle deep drilling hole and the bottom plate deep drilling hole are sequentially arranged side by side and are mutually spaced by-m, sealing observation barrels are arranged in the bottom plate shallow drilling hole, the bottom plate middle deep drilling hole and the bottom plate deep drilling hole, the sealing observation barrels are exposed out of drilling holes by 0.5-1.0 m, and detection positioning components are arranged in the sealing observation barrels;
the sealing observation cylinder comprises a plurality of transparent hollow pipes which are connected with each other, adjacent transparent hollow pipes are connected together by a butt joint sealing assembly, the butt joint sealing assembly comprises a butt joint sleeve and U-shaped clamp springs which are arranged at two ends of the butt joint sleeve, two ends of the butt joint sleeve are respectively sleeved at the ends of the adjacent transparent hollow pipes, and the two U-shaped clamp springs respectively penetrate through the butt joint sleeve from a butt joint hole on the cylinder wall of the butt joint sleeve and a through groove of the transparent hollow pipe in a perpendicular manner, so that the butt joint sleeve and the adjacent transparent hollow pipes are connected together;
The sealing observation barrel bottom is provided with a bottom sealing assembly, the bottom sealing assembly comprises a bottom sealing sleeve, the bottom sealing sleeve is fixed at one end of the sealing observation barrel bottom, the bottom of the bottom sealing sleeve is provided with a bottom sealing surface, and waterproof O-shaped gaskets are arranged between the bottom sealing surface of the bottom sealing sleeve and the sealing observation barrel bottom and at the butt joint positions of the adjacent transparent hollow pipes; the butt joint sleeve and the outer wall of the back cover sleeve are both provided with anti-deviation parts, the anti-deviation parts comprise three anti-deviation positioning pins which are distributed on the outer wall of the sleeve along the circumferential direction of the sleeve, the three anti-deviation positioning pins are screwed into the positioning pin threaded holes along the radial direction of the sleeve and fastened on the wall of the sleeve, and the outer ends of the anti-deviation positioning pins are 2-5 mm away from the wall of the drilled hole;
the device comprises a sealing observation cylinder, a drilling grouting body, a measuring component and an anchor adhesive, wherein a large-fluidity shrinkage-free grouting material is arranged between the sealing observation cylinder and the wall of the drilling hole, the wall of the inner side of the sealing observation cylinder is provided with the measuring component, the measuring component comprises a plurality of sections of measuring scales connected with each other, the length of each section of measuring scale is consistent with that of a transparent hollow pipe, one surface of the measuring scale is marked with scales, and the other surface of the measuring scale is fixedly adhered to the inner wall of the transparent hollow pipe through the anchor adhesive;
The detection positioning assembly comprises an intrinsic safety type drilling peeping instrument which is connected with the drilling peeping instrument through a cable, a positioning sleeve is arranged outside the intrinsic safety type drilling peeping instrument, three screws surrounding the positioning sleeve are screwed in from the outer wall of the positioning sleeve along the radial direction of the positioning sleeve respectively, and the positioning sleeve is fixed on the intrinsic safety type drilling peeping instrument; the cylinder wall of the positioning sleeve is provided with a plurality of springs in a distributed manner, the springs radially extend along the positioning sleeve, one end of each spring is welded on the positioning sleeve, and the other end of each spring is fixedly provided with a scratch-resistant ball.
Preferably, the U-shaped clamp spring is made of spring steel, and the ends of the two fixed support legs of the U-shaped clamp spring are outwards opened. After the U-shaped clamp spring is sent into a drilling hole, the end part of the U-shaped clamp spring fixing support leg is outwards opened, so that the wall of the drilling hole can be clamped, and the falling-off condition can not occur.
Preferably, the positions of the opposite perforations on the wall of the butt joint sleeve and the through grooves of the transparent hollow tube correspond to each other, and the diameters of the opposite perforations are the same as the diameters of the fixed support legs of the U-shaped clamp springs. Therefore, the fixing support leg of the U-shaped clamp spring can be tightly matched with the butt joint hole, and the butt joint sleeve can be used for firmly connecting the transparent hollow pipes.
Preferably, the material of the butt joint sleeve and the transparent hollow tube is resin fiber or acrylic organic glass. The organic transparent material is selected, so that on one hand, the strength of the material is ensured, and the material cannot be broken when being stressed; on the other hand, the transparency can be ensured, and the crack development condition can be conveniently observed.
Preferably, the anti-deviation locating pin is made of stainless steel, and the outer end of the anti-deviation locating pin is hemispherical. The stainless steel can prevent corrosion, guarantees safe in utilization, and hemispherical terminal surface can prevent off tracking locating pin's outer end and bottom plate drilling's pore wall when the bottom plate drilling produces the crack and takes place severe deformation and take place serious collision wearing and tearing, extension device's life simultaneously.
Preferably, the inner and outer diameters of the waterproof O-shaped gasket are consistent with those of the transparent hollow tube. The arrangement can ensure the sealing effect and prevent liquid from entering.
Preferably, the high-fluidity shrinkage-free grouting material comprises 40-55% of early strength Portland cement, 4-13% of reinforcing agent, 35-50% of aggregate, 0.3-1.6% of high-efficiency water reducing agent, 2-8% of expanding agent, 0.01-0.6% of fluid loss additive, 0.01-0.2% of anti-shrinkage agent, 0.1-0.8% of defoaming agent and 0.5% of retarder, and the weight ratio of the water cement is 0.12-0.20;
The early strength high-strength silicate cement is 42.5R silicate cement or 52.5R silicate cement or a mixture of silicate cement and aluminate cement in a weight ratio of 8:1;
the reinforcing agent is superfine fly ash or high-calcium fly ash, and the specification is 200-300 meshes;
the aggregate is quartz sand, and the particle size distribution is 0-1.25 mm;
the high-efficiency water reducer is a polycarboxylic acid polymer high-efficiency water reducer;
the expanding agent is a UEA high-efficiency low-alkali concrete expanding agent or a WZ-MPC polymer fiber expanding agent;
the fluid loss agent is hydroxyethyl cellulose;
the shrinkage inhibitor is polypropylene fiber;
the defoaming agent is an amino polyether defoaming agent or an organic silicon defoaming agent;
the retarder is one of lithospermic acid, citric acid, boric acid and phosphate.
Preferably, the measuring scale has a measuring range of 1m or 2m. During observation, the position of the surrounding rock crack in the drilled hole is directly read through the measuring ruler, and compared with the distance data indirectly obtained in the prior art, the error is small.
Preferably, the intrinsically safe borehole peeping instrument comprises an intrinsically safe borehole camera.
Preferably, the positioning sleeve is made of stainless steel or aluminum. Stainless steel or aluminum material is not easy to rust, so that the positioning sleeve can play an effective protective role while being positioned.
The invention also provides a method for monitoring the development of the reserved coal pillar gob-side entry retaining floor crack, which comprises the following steps:
step 2, constructing drilling holes with different depths below the bottom plate of the layer to be mined by adopting a coal mine intrinsic safety type tunnel drilling machine along the x direction of the cross section in a drilling field of the bottom plate, namely, drilling holes in the shallow part of the bottom plate, drilling holes in the middle of the bottom plate and drilling holes in the deep part of the bottom plate, wherein the distance between adjacent drilling holes is 1-2 m;
and 10, after the coal seam to be mined passes through the drill site position of the bottom plate and the compaction of the water guide fracture zone area above the goaf is stable, observing the development rule of the surrounding rock fracture of the mining surrounding rock of the bottom plate for the third time, repeating the processes of the steps 7-8, recording the conditions of the surrounding rock fracture on drilling grouting bodies on different scales on the measuring scale of the transparent hollow pipe in the shallow drilling hole, the deep drilling hole and the deep drilling hole of the bottom plate, and comparing and analyzing the observation result with the first observation result and the second observation result to define the development form of the damaged area of the bottom plate after coal seam mining.
Compared with the prior art, the invention has the following advantages:
(1) the detection system has reasonable overall structural design, a plurality of transparent hollow tubes are connected and fixed together through the butt joint sealing assembly and the back cover sealing assembly to form the sealing observation cylinder, and the structure is shaped by pouring the large-fluidity shrinkage-free grouting material, so that the damage force can be effectively resisted, the drilling safety and stability of the bottom plate can be ensured, the occurrence of drilling collapse hole accidents can be avoided, the drilling hole repairing condition of the bottom plate can be avoided, time and labor are saved, and effective data can be acquired in time; the safety monitoring can be continuously carried out for many times after one-time installation and positioning, the cost is saved, and the utilization rate of drilling holes is improved;
(2) by the implementation of the invention, the complex bottom plate geological structures such as hard rock stratum, soft and hard rock stratum, fault fracture zone passing and the like can be effectively treated, the problems of water softening shrinkage cavity, aperture closing and the like of the soft rock bottom plate are greatly overcome, the cost of repeated hole repairing and drilling is saved, the characteristic observation data of the bottom plate damage is effectively collected before and after working face mining, the drilling holes do not need to be frequently replaced, the development condition of cracks at different stages is observed by using the drilling holes at the same position, and the data is true and reliable.
(3) The detection positioning assembly arranged in the sealed observation cylinder can effectively protect the intrinsic safety drill Kong Kuishi instrument, the position is stable and accurate during detection, the spring has a flexible bending adjusting function, the impact on the intrinsic safety drill Kong Kuishi instrument can be reduced by utilizing elastic force to automatically adjust even after the detection is stressed, the anti-scraping ball is convenient for the intrinsic safety drilling peeping instrument to move up and down, the condition that the drilling monitoring section is blocked and blocked is avoided, uncontrollable factors are greatly reduced, and the instrument loss and material cost are saved;
(4) the fluidity of the large-fluidity shrinkage-free grouting material hermetically poured between the sealing observation cylinder and the bottom plate drilling hole can reach 260-380mm, and under the condition of low water cement ratio, the high fluidity can be obtained, the small-aperture filling space can be completed without manual vibration or stirring, and the self-compaction and self-leveling effects are realized; the vertical expansion rate of the material in one day is 0.03-0.65%, and the material can be adjusted, so that the shrinkage condition of a small-aperture filling area of the drilled hole is avoided, the separation phenomenon of a transparent hollow tube and a drilling grouting body is avoided, and the bonding surface is ensured to be seamless and not loose; the early strength is high, the compressive strength is 20-45 MPa in 1 day, the strength can reach 45-60 MPa in 28 days, and the construction monitoring can be realized in the next day after the sleeve is installed; the corrosion resistance to acid groundwater is good, the corrosion resistance to transparent hollow tubes is avoided, and the long-term monitoring can be realized.
After the large-fluidity shrinkage-free grouting material is poured and molded, on one hand, water burst accidents caused by the rising of bottom plate water along a drilling hole can be prevented, and the detection positioning component and the drilling hole are protected from being polluted by mud water, sewage, suspended matters in oil-water mixture and water and bubbles to influence observation; on the other hand, after the large-fluidity shrinkage-free grouting material is molded, the grouting material and surrounding rock bodies belong to inorganic materials, the physical and mechanical properties of the grouting material are similar, the stress characteristics of the grouting material can be changed along with the change of the physical properties of the surrounding rock bodies, the grouting material and the surrounding rock bodies are deformed in a coordinated manner, the positions and the forms of the cracks on the drilling grouting body are directly read out through the transparent hollow pipe by combining an intrinsic safety drill Kong Kuishi instrument with a measuring ruler, namely the positions of the cracks of the bottom plate surrounding rock in the drilling holes, compared with the slit distance position data obtained indirectly in the prior art, the error is greatly reduced, the result is visual and reliable, and the positions and the development conditions of the rock stratum change can be rapidly and accurately obtained.
(5) The test method provided by the invention belongs to a technology for safely, efficiently, quickly and timely collecting the damage characteristic observation data of the reserved coal pillar gob-side entry retaining bottom plate, wherein the bottom plate shallow drilling holes, the bottom plate middle deep drilling holes and the bottom plate deep drilling holes which are arranged side by side extend from a bottom plate drilling hole field to the bottom plate direction of a coal seam to be mined are arranged in a three-dimensional manner, the development form of a bottom plate plastic damage area in coal seam mining and the development form of a bottom plate damage area after coal seam mining can be defined by observing the adjacent drilling holes and the crack conditions of the same drilling hole in different coal mining stages at the same time, the basis is provided for the reservation of an effective water-resisting layer of the bottom plate, and the test method has great significance on the coal seam in the safe and stable mining pressure bearing; in addition, the effective grouting depth and grouting range of the bottom plate can be determined, accurate research, judgment and analysis are carried out on grouting reconstruction conditions of the bottom plate, the bottom plate water burst and water burst disaster during coal seam mining are avoided as much as possible, and reliable data reference is provided for safe construction. The method can be used for monitoring mining damage of the coal seam floor, monitoring the loosening ring damage rule of the surrounding rock of the roadway roof floor, monitoring deformation of the surrounding rock of the floor bottom bulging, and the like, and has good popularization value and practicality.
Drawings
FIG. 1 is a schematic diagram of the structure of the present invention;
FIG. 2 is an enlarged top view of FIG. 1 at A;
FIG. 3 is a schematic diagram of the structure of the invention when a water guiding fracture zone above a goaf is formed in mining of a coal seam;
FIG. 4 is a schematic diagram of a structure in which a coal seam to be mined is drilled at a drilling site of a bottom plate, and a water guiding fracture zone area above a goaf is compacted and stabilized;
FIG. 5 is a schematic view of the overall construction of the seal observation barrel of the present invention (a portion of the borehole grouting body is shown);
FIG. 6 is a schematic cross-sectional view of a seal observation barrel structure of the present invention (a portion of a borehole grouting body is shown);
FIG. 7 is a schematic view in section A-A of FIG. 6 (the borehole grouting body showing a portion) in accordance with the present invention;
FIG. 8 is a schematic view in section B-B of FIG. 6 (the borehole grouting body showing a portion) in accordance with the present invention;
FIG. 9 is a schematic view in section C-C of FIG. 6 (drilling grouting showing a portion) in accordance with the present invention;
FIG. 10 is a schematic view of the section D-D of FIG. 6 (drill grouting body shown as part of) in accordance with the present invention;
FIG. 11 is a schematic view in section E-E of FIG. 6 (drilling grouting showing a portion) of the present invention;
FIG. 12 is an enlarged view of the internal partial structure of FIG. 11 in accordance with the present invention;
FIG. 13 is an enlarged view of the structure of the detecting and positioning assembly inside the sealed observation tube of the present invention;
Detailed Description
The invention is described in further detail below with reference to the accompanying drawings.
As shown in the figure, a system for monitoring the crack development of a reserved coal pillar gob-side entry retaining bottom plate comprises a gob-side entry retaining 29 and a lower gate 31 which are parallel, wherein a section coal pillar 30 is reserved between the gob-side entry retaining 29 and the lower gate 31, the other side of the lower gate 31 is provided with a coal seam to be mined 32, the other side of the coal seam to be mined 32 is an upper gate 33, one side of the gob-side entry retaining 29, which is close to an adjacent mining surface 27, is provided with a bottom plate drilling site 28, a bottom plate shallow drilling hole 37, a bottom plate middle deep drilling hole 38 and a bottom plate deep drilling hole 39 are extended from the bottom plate drilling site to the bottom plate direction of the coal seam to be mined, the periphery is a drilling wall surrounding rock body 1, the bottom plate shallow drilling hole 37, the bottom plate middle deep drilling hole 38 and the bottom plate deep drilling hole 39 are sequentially arranged side by side, the distance between each drilling hole and the longitudinal axis direction of the gob-side entry retaining 29 is 1-2 m, sealing observation cylinders are arranged in the bottom plate shallow drilling hole 37, the bottom plate middle deep drilling hole 38 and the bottom plate deep drilling hole 39, the sealing observation cylinders expose 0.5-1.0 m, and a detection positioning assembly is arranged in the sealing observation cylinders;
the sealing observation cylinder comprises a plurality of transparent hollow pipes 8 which are connected with each other, adjacent transparent hollow pipes 8 are connected together by a butt joint sealing assembly, the butt joint sealing assembly comprises a butt joint sleeve 7 and U-shaped clamp springs 5 which are arranged at two ends of the butt joint sleeve 7, two ends of the butt joint sleeve 7 are respectively sleeved at the end parts of the adjacent transparent hollow pipes 8, the two U-shaped clamp springs 5 respectively penetrate through a butt joint through hole 6 on the wall of the butt joint sleeve 7 and a through groove 24 of the transparent hollow pipe 8 perpendicular to the butt joint sleeve 7, and the butt joint sleeve 7 and the adjacent transparent hollow pipes 8 are connected together;
The bottom sealing assembly comprises a bottom sealing sleeve 19, the bottom sealing sleeve 19 is fixed at one end of the bottom of the sealed observation cylinder through threaded connection, the bottom sealing sleeve 19 is provided with a bottom sealing surface 22 at the bottom, and waterproof O-shaped gaskets 11 are arranged between the bottom sealing surface 22 of the bottom sealing sleeve 19 and the bottom of the sealed observation cylinder and at the butt joint positions of adjacent transparent hollow pipes 8; the outer walls of the butt joint sleeve 7 and the back cover sleeve 19 are respectively provided with an anti-deviation component, the anti-deviation component comprises three anti-deviation positioning pins 9 which are distributed on the outer wall of the sleeve along the circumferential direction of the sleeve, the three anti-deviation positioning pins 9 are respectively screwed into the positioning pin threaded holes 10 along the radial direction of the sleeve and are fastened on the wall of the sleeve, and the outer ends of the anti-deviation positioning pins 9 are 2-5 mm away from the wall of the drilled hole;
the device comprises a sealing observation cylinder, a drilling grouting body 3 formed by solidifying a large-fluidity shrinkage-free grouting material between the sealing observation cylinder and the wall of the drilling hole, and a measuring part arranged on the wall of the inner side of the sealing observation cylinder, wherein the measuring part comprises a plurality of sections of measuring scales 4 connected with each other, the length of each section of measuring scale 4 is consistent with the length of a transparent hollow pipe 8, one surface is marked with scales, and the other surface is fixedly bonded on the inner wall of the transparent hollow pipe 8 through an anchoring adhesive 23;
The detection positioning assembly comprises an intrinsic safety type drilling peeping instrument 18, the intrinsic safety type drilling peeping instrument 18 is connected with a drilling peeping instrument 53 through a cable 12, a positioning sleeve 13 is arranged outside the intrinsic safety type drilling peeping instrument 18, three screws 15 surrounding the positioning sleeve 13 are respectively screwed in from the outer wall of the positioning sleeve 13 along the radial direction of the positioning sleeve 13, the positioning sleeve 13 is fixed on the intrinsic safety type drilling peeping instrument 18, the screws 15 are provided with external threads 25, and the external threads 25 are matched with the sleeve threaded holes 16; the cylinder wall of the positioning sleeve 13 is provided with a plurality of springs 17, the springs 17 extend radially along the positioning sleeve 13, one end of each spring is welded on the positioning sleeve 13, and the other end of each spring is fixed with a scratch-resistant ball 14. The spring 17 has a flexible bending function, and after being deformed under stress, the impact of impact force on the intrinsically safe drilling peeping instrument 18 can be reduced, and the scratch-resistant ball 14 facilitates the up-and-down movement of the detection positioning assembly in the transparent hollow tube 8, so that the equipment is prevented from being blocked.
Preferably, the material of the U-shaped clamp spring 5 is spring steel, and the two fixed leg ends of the U-shaped clamp spring 5 are outwards opened. After the drilling hole is sent into, the end part of the fixing support leg of the U-shaped clamp spring 5 is outwards opened, so that the wall of the drilling hole can be clamped, and the falling-off condition can not occur.
Preferably, the positions of the opposite perforations 6 on the wall of the butt joint sleeve 7 and the through grooves 24 of the transparent hollow tube 8 correspond, and the diameters of the opposite perforations 6 are the same as the diameters of the fixed support legs of the U-shaped clamp springs 5. Thereby the fixed landing leg of "U" shape jump ring 5 can with to perforation 6 tight fit, has guaranteed that butt joint sleeve 7 can be with transparent hollow tube 8 firmly connect.
Preferably, the material of the butt joint sleeve 7 and the transparent hollow tube 8 is resin fiber or acrylic plexiglas. The organic transparent material is selected, so that on one hand, the strength of the material is ensured, and the material cannot be broken when being stressed; on the other hand, the transparency can be ensured, and the crack development condition can be conveniently observed.
Preferably, the anti-deviation locating pin 9 is made of stainless steel, and the outer end of the anti-deviation locating pin is hemispherical. The stainless steel can prevent corrosion, guarantees safe in utilization, and hemispherical terminal surface can prevent off tracking locating pin 9's outer end and bottom plate drilling's pore wall to take place serious collision wearing and tearing when the bottom plate drilling produces the crack and takes place violent deformation simultaneously, extension device's life.
Preferably, the inner and outer diameters of the waterproof O-shaped gasket 11 are identical to those of the transparent hollow tube 8. Can ensure the sealing effect and prevent liquid from entering.
Preferably, the high-fluidity shrinkage-free grouting material comprises 40-55% of early strength Portland cement, 4-13% of reinforcing agent, 35-50% of aggregate, 0.3-1.6% of high-efficiency water reducing agent, 2-8% of expanding agent, 0.01-0.6% of fluid loss additive, 0.01-0.2% of anti-shrinkage agent, 0.1-0.8% of defoaming agent and 0.5% of retarder, and the weight ratio of the water cement is 0.12-0.20;
the early strength high-strength silicate cement is 42.5R silicate cement or 52.5R silicate cement or a mixture of silicate cement and aluminate cement in a weight ratio of 8:1;
the reinforcing agent is superfine fly ash or high-calcium fly ash, and the specification is 200-300 meshes;
the aggregate is quartz sand, and the particle size distribution is 0-1.25 mm;
the high-efficiency water reducer is a polycarboxylic acid polymer high-efficiency water reducer;
the expanding agent is a UEA high-efficiency low-alkali concrete expanding agent or a WZ-MPC polymer fiber expanding agent;
the fluid loss agent is hydroxyethyl cellulose;
the shrinkage inhibitor is polypropylene fiber;
the defoaming agent is an amino polyether defoaming agent or an organic silicon defoaming agent;
the retarder is one of lithospermic acid, citric acid, boric acid and phosphate.
Preferably, the measuring scale has a measuring range of 1m or 2m. During observation, the position of the surrounding rock crack in the drilled hole is directly read through the measuring ruler, and compared with the distance data indirectly obtained in the prior art, the error is small.
Preferably, the intrinsically safe borehole peeping device 18 comprises an intrinsically safe borehole camera.
Preferably, the positioning sleeve 13 is made of stainless steel or aluminum. Stainless steel or aluminum materials are not easy to rust, so that the positioning sleeve (13) can play an effective protective role while being positioned.
Specific examples:
firstly, preparing a certain proportion of large-fluidity shrinkage-free grouting material on the ground for underground standby. The high-fluidity shrinkage-free grouting material comprises the components of an inorganic gum base, a reinforcing agent, aggregate, a high-efficiency water reducing agent, an expanding agent, a fluid loss agent, an anti-shrinkage agent, a defoaming agent and a retarder, wherein the weight ratio of the components is 50%, 8.2%, 35.2%, 1.16%, 4.2%, 0.02%, 0.013%, 0.42% and 0.7%, and the water-cement ratio is 0.143. Wherein:
(1) the inorganic gum base is early strength high strength silicate cement, and the model is 42.5R silicate cement;
(2) the reinforcing agent is ultrafine fly ash with the specification of 200-300 meshes;
(3) the aggregate is quartz sand, the grain size distribution is 0-1.25 mm, wherein 0-0.16 mm accounts for 15%, 0.16-0.325 mm accounts for 35%, 0.325-0.85 mm accounts for 32%, and 0.85-1.25 mm accounts for 18%;
(4) The high-efficiency water reducer is a polycarboxylic acid polymer high-efficiency water reducer;
(5) the expanding agent is a UEA high-efficiency low-alkali concrete expanding agent;
(6) the fluid loss agent is hydroxyethyl cellulose;
(7) the shrinkage inhibitor is polypropylene fiber;
(8) the defoaming agent is an amino polyether defoaming agent;
(9) the retarder is lithospermic acid;
the method for monitoring the development of the reserved coal pillar gob-side entry retaining floor crack specifically comprises the following steps:
And 2, constructing drilling holes with different depths (drilling final hole diameter phi=105 mm) below the bottom plate of the layer 32 to be mined by adopting a coal mine intrinsic safety type MK-4 tunnel drilling machine along the cross section x direction in the bottom plate drilling field 28, namely, a bottom plate shallow drilling hole 37 (vertical depth 13.2m, 20-degree downward inclination angle), a bottom plate middle deep drilling hole 38 (vertical depth 21.6m, 34-degree downward inclination angle) and a bottom plate deep drilling hole 39 (vertical depth 25.3m, 41-degree downward inclination angle), wherein the distance between adjacent drilling holes along the longitudinal axis direction of the gob-side entry retaining 29 is 1.5m. If the 0-2 m position of the coal bed bottom plate under the section coal pillar 30 is aluminum mudstone, a wall protection sleeve with the vertical depth of 2m needs to be put into 3 drilling holes to prevent the drilling holes from collapsing.
And 3, after the construction of the bottom plate shallow drilling 37, the middle deep drilling 38 and the deep drilling 39 is finished, firstly connecting the multi-section measuring scale 4 with the transparent hollow pipe 8 (taking the length of 1m as an example) and the scales (0-1.0 m, 1.0-2.0 m, 2.0-3.0 m, and so on) to the inner wall of the transparent hollow pipe 8 by adopting the anchoring adhesive 23, marking the scale ranges of the measuring scales 4 on the transparent hollow pipe 8 from small to large with shallow 1, shallow 2 and shallow 3 … … … … for standby.
Step 4, in the shallow part drilling 37 of the constructed bottom plate, a waterproof O-shaped gasket 11 (the inner diameter phi=45 mm, the outer diameter phi=55 mm and the thickness 6 mm) is placed at the bottom of the bottom sealing sleeve 19, the internal thread 20 of the bottom sealing sleeve 19 is matched with the external thread 21 of the transparent hollow tube 8, the bottom sealing sleeve 19 is screwed at the initial end of the measuring range of the transparent hollow tube 8 marked with the shallow 1, and the anti-deviation positioning pins 9 are screwed at the three positioning pin threaded holes 10 distributed on the wall of the bottom sealing sleeve 19 around the bottom sealing sleeve 19; then, a waterproof O-shaped gasket 11 is placed at the other end part of the transparent hollow tube 8 marked with the shallow 1, one section of butt joint sleeve 7 (the inner diameter phi=55 mm, the outer diameter phi=65 mm and the wall thickness 5 mm) is sleeved into the other end of the transparent hollow tube 8 marked with the shallow 1, the positions of the through holes 6 and the through grooves 24 of the transparent hollow tube 8 are aligned, and a U-shaped clamp spring 5 is inserted, so that the butt joint sleeve 7 is fixed on the transparent hollow tube 8 marked with the shallow 1; the initial end of the measuring range of the transparent hollow tube 8 marked with the shallow 2 is butted with the exposed opening of the butting sleeve 7, another U-shaped clamp spring 5 is inserted into the corresponding position, and the transparent hollow tube 8 marked with the shallow 2 is fixed with the butting sleeve 7; the anti-deviation locating pins 9 are screwed at three locating pin threaded holes 10 distributed on the middle cylinder wall of the butt joint sleeve 7 around the butt joint sleeve 7; slowly feeding the butted 'shallow 1' and 'shallow 2' transparent hollow pipes 8 into a bottom plate shallow part drilling hole 37, similarly installing transparent hollow pipes 8 marked with 'shallow 3', 'shallow 4' … … at the other end of the 'shallow 2' transparent hollow pipe 8 exposed out of the bottom plate shallow part drilling hole 37 hole until the 'shallow 1' transparent hollow pipe 8 falls into the bottom of the bottom plate shallow part drilling hole 37 hole, thereby installing the shallow part sealing observation cylinder, and simultaneously, exposing the last section of transparent hollow pipe 8 for a safe distance of 0.5-1 m from the drilling hole so as to prevent the butted transparent hollow pipe 8 from entering sewage or grouting slurry from flowing backwards.
and 6, after the transparent hollow pipes 8 are installed in place in the bottom plate shallow part drilling holes 37, the bottom plate middle deep drilling holes 38 and the bottom plate deep drilling holes 39, adding mixing water into the grouting material according to the water-cement ratio of 0.143, fully mixing, and filling the grouting material into gaps among the bottom plate shallow part drilling holes 37, the bottom plate middle deep drilling holes 38, the bottom plate deep drilling holes 39 and the sealing observation cylinder to finally form the drilling grouting body 3.
And 7, observing the mining fracture of the primary bottom plate after the grouting body to be drilled 3 reaches the compressive strength for 3 days. An intrinsically safe borehole peeping device 18, such as a camera, is first connected in sequence in place with a borehole peeping device 53 of a data acquisition host via an electrical cable 12.
Step 9, when the coal seam 32 to be mined is in mining, and the coal face is 1-2 cycles away from the bottom plate drilling site 28 to press the step distance, the goaf forms a water guide fracture zone 34 above the goaf, at the moment, secondary observation of the development rule of the bottom plate mining surrounding rock fracture is carried out, the process of step 8 is repeated, surrounding rock fracture conditions on the drilling grouting bodies 3 on different scales on the measuring scales 4 of the transparent hollow pipes 8 in the bottom plate shallow drilling 37, the bottom plate deep drilling 38 and the bottom plate deep drilling 39 are recorded, and the observation result and the first observation result are compared and analyzed, so that the development form 35 of the plastic damage region of the bottom plate in coal seam mining is primarily judged; due to the influence of disturbance of coal seam mining, the stress of the bottom plate is changed, the drilling grouting body 3 positioned in the development form 35 of the plastic damage area of the bottom plate in mining is damaged by tension, compression and shearing, the crack development of the drilling grouting body 3 can be directly observed by the intrinsic safety type drill Kong Kuishi instrument 18 at the lower part in the transparent hollow tube 8, a good observation result can be obtained, and the problems of clamping and blocking of camera equipment and incapability of up and down can be avoided by the detection positioning assembly. The actual observation result of the second site is fed back to technicians, so that the crack change of the drilling grouting body 3 can be intuitively known, and the crack change of the drilling grouting body 3 directly reflects the crack development rule of the mining surrounding rock of the bottom plate; in addition, accurate research, judgment and analysis can be carried out on the grouting reconstruction condition of the bottom plate of the coal mining machine, so that the bottom plate water burst and water burst disasters during the coal mining process are avoided as much as possible.
In the embodiment, only three observations are performed, the number of observations can be increased according to the actual requirements of the site, and the development process of the bottom plate crack can be accurately known by improving the observation density.
Claims (1)
1. The method for monitoring reserved coal pillar gob-side entry retaining bottom plate crack development comprises a gob-side entry retaining (29) and a lower gate (31) which are parallel, wherein a section coal pillar (30) is reserved between the gob-side entry retaining (29) and the lower gate (31), a coal mining layer (32) to be mined is arranged on the other side of the lower gate (31), a bottom plate drilling field (28) is arranged on one side, close to an adjacent mining surface (27), of the gob-side entry retaining (29), a bottom plate shallow drilling hole (37), a bottom plate middle deep drilling hole (38) and a bottom plate deep drilling hole (39) are arranged in an extending mode from the bottom plate drilling field to the bottom plate direction of the coal mining layer, and the bottom plate shallow drilling hole (37), the bottom plate middle deep drilling hole (38) and the bottom plate deep drilling hole (39) are sequentially arranged side by side and are mutually separated by 1-2 m;
The bottom plate shallow drilling (37), the bottom plate middle deep drilling (38) and the bottom plate deep drilling (39) are respectively provided with a sealing observation cylinder, the sealing observation cylinders are exposed out of the drilling holes by 0.5-1.0 m, and the sealing observation cylinders are internally provided with detection positioning components;
the sealing observation tube comprises a plurality of mutually connected transparent hollow tubes (8), adjacent transparent hollow tubes (8) are connected together by a butt joint sealing assembly, the butt joint sealing assembly comprises a butt joint sleeve (7) and U-shaped clamp springs (5) arranged at two ends of the butt joint sleeve (7), two ends of the butt joint sleeve (7) are respectively sleeved at the end parts of the adjacent transparent hollow tubes (8), the two U-shaped clamp springs (5) are respectively perpendicular to the butt joint sleeve (7) and penetrate through a butt joint hole (6) on the wall of the butt joint sleeve (7) and a through groove (24) of the transparent hollow tube (8), and the butt joint sleeve (7) and the adjacent transparent hollow tubes (8) are connected together;
the bottom of the sealed observation cylinder is provided with a bottom sealing assembly, the bottom sealing assembly comprises a bottom sealing sleeve (19), the bottom sealing sleeve (19) is fixed at one end of the bottom of the sealed observation cylinder, the bottom of the bottom sealing sleeve (19) is provided with a bottom sealing surface (22), and waterproof O-shaped gaskets (11) are arranged between the bottom sealing surface (22) of the bottom sealing sleeve (19) and the bottom of the sealed observation cylinder and at the butt joint positions of the adjacent transparent hollow tubes (8); the outer walls of the butt joint sleeve (7) and the back cover sleeve (19) are respectively provided with an anti-deviation component, the anti-deviation component comprises three anti-deviation locating pins (9) which are distributed on the outer wall of the sleeve along the circumferential direction of the sleeve, the three anti-deviation locating pins (9) are respectively screwed into locating pin threaded holes (10) on the wall of the sleeve along the radial direction of the sleeve and fastened on the wall of the sleeve, and the distance between the outer end of each anti-deviation locating pin (9) and the wall of a drilled hole is 2-5 mm;
The detection positioning assembly comprises an intrinsic safety type drilling peeping instrument (18), the intrinsic safety type drilling peeping instrument (18) is connected with a drilling peeping instrument (53) through a cable (12), a positioning sleeve (13) is arranged outside the intrinsic safety type drilling peeping instrument (18), three screws (15) surrounding the positioning sleeve (13) are respectively screwed in from the outer wall of the positioning sleeve (13) along the radial direction of the positioning sleeve (13), and the positioning sleeve (13) is fixed on the intrinsic safety type drilling peeping instrument (18); a plurality of springs (17) are distributed on the wall of the positioning sleeve (13), the springs (17) radially extend along the positioning sleeve (13), one end of each spring is welded on the positioning sleeve (13), and the other end of each spring is fixedly provided with a scratch-resistant ball (14);
the method is characterized by comprising the following steps of:
step 1, mining a coal seam (32) to be mined in a mode of reserving section coal pillars (30), reserving the section coal pillars (30) between a gob-side entry retaining way (29) and a lower gate way (31), and constructing a bottom plate drilling field (28) on one side of the gob-side entry retaining way (29) close to an adjacent mining surface (27);
step 2, constructing drilling holes with different depths, namely a shallow drilling hole (37) of the bottom plate, a deep drilling hole (38) in the bottom plate and a deep drilling hole (39) of the bottom plate, in the bottom plate drilling field (28) along the cross section x direction by adopting a coal mine intrinsic safety type tunnel drilling machine, wherein the distance between adjacent drilling holes is 1-2 m;
Step 3, after the construction of the bottom plate shallow drilling hole (37), the bottom plate middle deep drilling hole (38) and the bottom plate deep drilling hole (39) is finished, firstly, respectively bonding a plurality of sections of measuring scales (4) which are the same as the transparent hollow tube (8) in length and are connected with scales on the inner wall of the transparent hollow tube (8) by adopting an anchor adhesive (23), and marking 'shallow 1', 'shallow 2', 'shallow 3' … … on the transparent hollow tube (8) from small to large according to the scale range of each section of measuring scale (4) for standby;
step 4, in a drilled hole (37) at the shallow part of a constructed bottom plate, a waterproof O-shaped gasket (11) is placed at the bottom of a bottom sealing sleeve (19), the bottom sealing sleeve (19) is screwed at the initial end of the measuring range of a transparent hollow tube (8) marked with a shallow 1, and deviation-preventing positioning pins (9) are screwed at three positioning pin threaded holes (10) distributed on the wall of the bottom sealing sleeve (19) around the bottom sealing sleeve (19); then, a waterproof O-shaped gasket (11) is placed at the other end part of the transparent hollow tube (8) marked with the shallow 1, a section of butt joint sleeve (7) is sleeved into the other end of the transparent hollow tube (8) marked with the shallow 1, and the positions of the through holes (6) and the through grooves (24) of the transparent hollow tube (8) are aligned; inserting a U-shaped clamp spring (5) so as to fix the butt joint sleeve (7) on the transparent hollow tube (8) marked with a shallow 1; the initial end of the measuring range of the transparent hollow tube (8) marked with the shallow 2 is butted with the exposed opening of the butting sleeve (7), another U-shaped clamp spring (5) is inserted into the corresponding position, and the transparent hollow tube (8) marked with the shallow 2 is fixed with the butting sleeve (7); the anti-deviation locating pins (9) are screwed at three locating pin threaded holes (10) distributed on the middle cylinder wall of the butt joint sleeve (7) around the butt joint sleeve (7); slowly feeding the butted transparent hollow tubes (8) marked with shallow 1 and shallow 2 into a bottom plate shallow part drilling hole (37), and similarly installing the transparent hollow tubes (8) marked with shallow 3 and shallow 4 … … at the other end of the bottom plate shallow part drilling hole (37) exposed out of the transparent hollow tube (8) marked with shallow 2 until the transparent hollow tube (8) marked with shallow 1 falls into the bottom of the bottom plate shallow part drilling hole (37), and simultaneously, exposing the last section of transparent hollow tube (8) to a safe distance of 0.5-1 m from the drilling hole opening, thereby installing the shallow part sealing observation tube;
Step 5, repeating the process of the step 3-4, manufacturing transparent hollow tubes (8) marked as 'medium 1', 'medium 2', 'medium 3', '… … and' deep 1 ',' deep 2 ',' deep 3 ',' … … ', installing the transparent hollow tubes (8) marked as' medium 1 ',' medium 2 ',' medium 3 ',' … … in a deep drilling hole (38) of a bottom plate, and installing the transparent hollow tubes (8) marked as 'deep 1', 'deep 2', 'deep 3' … … in a deep drilling hole (39) of the bottom plate to respectively form a medium-deep sealing observation cylinder and a deep sealing observation cylinder;
step 6, after each transparent hollow tube (8) is installed in place in a shallow bottom plate drilling hole (37), a deep bottom plate drilling hole (38) and a deep bottom plate drilling hole (39), a large-fluidity shrinkage-free grouting material is selected according to lithology of a surrounding stratum of the bottom plate, and after mixing water is added into the grouting material according to a water cement ratio of 0.12-0.20, the grouting material is poured into gaps among the shallow bottom plate drilling hole (37), the deep bottom plate drilling hole (38) and the deep bottom plate drilling hole (39) and corresponding sealing observation cylinders to form a drilling grouting body (3);
step 7, after the compressive strength of the grouting body (3) to be drilled reaches 3 days, carrying out primary bottom plate mining fracture observation, and firstly connecting an intrinsic safety drill Kong Kuishi instrument (18) with a drilling peeping device (53) of a data acquisition host computer in place through a cable (12);
Step 8, penetrating an intrinsically safe drilling peeping instrument (18) through a positioning sleeve (13) with an anti-scratch ball (14) arranged on the outer wall, respectively screwing three screws (15) surrounding the positioning sleeve (13) from the outer wall of the positioning sleeve (13) along the radial direction of the positioning sleeve (13), fixing the positioning sleeve (13) on the intrinsically safe drilling peeping instrument (18), and enabling the central axis of the positioning sleeve (13) to coincide with the central axis of the intrinsically safe drilling peeping instrument (18); then slowly lowering an intrinsic safety type drilling peeping instrument (18) sleeved with a positioning sleeve (13) in a transparent hollow tube (8) which is connected with a bottom plate shallow drilling hole (37), a bottom plate middle deep drilling hole (38) and a bottom plate deep drilling hole (39) in sequence, recording the primary peeping video content in real time by the drilling peeping instrument (53), and recording the development condition of surrounding rock cracks on the drilling grouting body (3) in detail through scales on a measuring scale (4) on the inner wall of the transparent hollow tube (8);
step 9, when the coal seam (32) to be mined is in mining, and the working face of the coal seam is 1-2 cycles away from the drilling site (28) of the bottom plate to press the step distance, the goaf forms a water guide fracture zone (34) above the goaf, at the moment, secondary observation of the development rule of surrounding rock fracture of the bottom plate mining is carried out, the process of step 8 is repeated, surrounding rock fracture conditions on drilling grouting bodies (3) on different scales on a measuring scale (4) of a transparent hollow pipe (8) in the shallow drilling hole (37) of the bottom plate, the deep drilling hole (38) of the bottom plate and the deep drilling hole (39) of the bottom plate are recorded, and the observation result and the first observation result are compared and analyzed to preliminarily judge the development form (35) of the plastic damage region of the bottom plate in the coal seam mining;
And 10, after the layer (32) to be mined passes through the position of the drilling hole field (28) of the bottom plate and the compaction of the area of the water guide fracture zone (34) above the goaf is stable, observing the development rule of the surrounding rock fracture of the mining surrounding rock of the bottom plate for the third time, repeating the processes of the steps 7-8, recording the conditions of the surrounding rock fracture on the drilling grouting body (3) on different scales on the measuring scale (4) of the transparent hollow tube (8) in the shallow drilling hole (37) of the bottom plate, the deep drilling hole (38) in the bottom plate and the deep drilling hole (39) of the bottom plate, and comparing and analyzing the observation result with the first observation result and the second observation result to define the development form (36) of the damaged area of the bottom plate after the coal mining.
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| CN108922293B (en) * | 2018-05-17 | 2020-07-07 | 中国矿业大学(北京) | A multi-functional simulation frame for mining teaching and laboratory test |
| CN114109502A (en) * | 2020-08-25 | 2022-03-01 | 神华神东煤炭集团有限责任公司 | Detection method for self-repairing degree of overburden fracture in mining area and application of detection method |
| CN113219141B (en) * | 2021-06-01 | 2023-03-14 | 盾构及掘进技术国家重点实验室 | Grooved pipe device for micro-fracture development characteristics in tunnel surrounding rock and monitoring method |
| CN113622907B (en) * | 2021-09-07 | 2023-02-14 | 中国矿业大学 | Single-hole synchronous monitoring method for movement and fracture distribution in coal seam mining overburden rock |
| CN114295034A (en) * | 2022-01-15 | 2022-04-08 | 黑龙江省农业机械工程科学研究院 | Tilling depth monitoring device |
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| CN103389521B (en) * | 2013-07-26 | 2016-08-10 | 山东大学 | Deep laneway surrounding rock subregion ruptures in-situ measurement system and detection method |
| CN203729976U (en) * | 2014-01-09 | 2014-07-23 | 中国矿业大学 | All-dimensional peeping probe and positioning device for coal mine downhole drilling |
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