CN111812296A - Pressure relief mining analog simulation method - Google Patents
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Abstract
The invention provides a pressure relief mining analog simulation method. The method comprises the steps of selecting a printing wire, 3D printing a coarse model, simulating the deformation process of the protected layer, obtaining the deformation rule of the protected layer under the influence of the mining of the upper and lower protection layers and the like. According to the method, on the basis of 3D printing, the deformation of the material is controlled, so that the experiment period is shortened again, the human resources are reduced, the experiment can be carried out under the approximately same condition after each printing, and the stable and reliable scientific rule is facilitated. Meanwhile, the method has obvious advantages in the aspect of investigating the pressure relief and permeability increasing effects of different protective layer mining schemes, and provides an auxiliary supporting means for the mining design of coal mines.
Description
Technical Field
The invention relates to the field of mine engineering, in particular to a mining simulation method for protective layer mining.
Background
Coal mine gas control is always the key and difficult point of coal mine disaster control. Although China has made great progress on coal and gas outburst treatment at present, the research of outburst treatment technology is still a firm task. In the prior art, the pressure-relief permeability-increasing technology for mining a protective layer which is widely applied is characterized in that a coal seam above or below a target coal seam is mined to deform the target coal seam under the action of ground stress, so that the stress applied to the coal seam is reduced, and the permeability of gas can be increased through cracks generated by deformation, thereby achieving the effects of pressure relief and permeability increase. At present, the technical effect is obvious and the feasibility is high, but in the determination of the specific embodiment, a great deal of preliminary work is needed. Especially, when multiple coal seams are mined, the determination of the specific position and mining range of the protective layer becomes a technical difficulty. If the protected range and the pressure relief and permeability improvement effect of the mined protective layer can be obtained by a similar simulation method when a protective layer mining scheme is designed, important auxiliary support is provided for scheme design, and the scheme selection process is more scientific and reasonable.
Therefore, it is highly desirable to develop a mining simulation method for overburden mining.
Disclosure of Invention
The invention aims to provide a pressure relief mining analog simulation method to solve the problems in the prior art.
The technical scheme adopted for achieving the purpose of the invention is that the pressure relief mining simulation method comprises the following steps:
1) selecting different shape memory polymers as printing wires of the rock stratum, the protected layer and the protection layer.
2) And 3D printing is carried out according to the geometric similar template of the rock coal layer to be printed, the structural similar model of the rock coal layer and the basic characteristics of each coal layer. And obtaining a similar stratum model containing a protective layer block and a protected layer. Among them, the basic characteristics of coal strata include volume weight, compressive strength and shear strength.
3) And gradually taking out the protective layer blocks from the stratum model to simulate the mining process of the protective layer, controlling the position, speed and range of the mining of the protective layer by taking out the position, speed and number of the blocks, and observing the processes of overburden fracture, overburden collapse, fracture initiation and fracture development in the mining process.
4) And putting the mined protective layer block into the model again, restoring the stratum to the original shape through external field stimulation, and healing the broken memory material.
5) And (5) repeating the step 3) and the step 4) to obtain the deformation damage condition of the protected layer under different protected layer mining conditions.
Further, after the step 5), the related steps of obtaining the pressure relief and permeability increase range and effect of the protective layer according to the deformation and damage conditions of the protected layer and selecting the optimal protective layer mining scheme are also provided.
Further, the protective layer shape memory polymer comprises the following components in parts by weight: 20 parts of quartz sand, 10 parts of polyethylene, 30 parts of rubber, 10 parts of barite powder, 4 parts of gypsum, 10 parts of fine wood dust and 4-6 parts of paraffin.
The composition and the parts by mass of the protected shape memory polymer are as follows: 20 parts of quartz sand, 30 parts of barite powder, 10 parts of an expansion deformation agent, 6 parts of an antirust agent, 10 parts of aggregate and 4-6 parts of paraffin.
Further, in the 3D printing process, mica powder is used as a separation material between layers. .
Further, printing is performed by repeatedly laminating the shape memory polymer from bottom to top.
Further, a dynamic crack detector, an acoustic emission device and a strain gauge.
The technical effects of the invention are undoubted:
A. the pressure relief and permeability increase mechanism of the protective layer is clear at a glance, and the investigation of the pressure relief and permeability increase effect is very easy;
B. the experimental conditions can be ensured to be approximately similar when the experiment is carried out each time, and the experimental error caused by factors such as seasons, environment and the like is reduced;
C. in the same experiment, the material can be recovered by using light and other exciting factors, so that the influence on the protected layer in the process of researching the protective layer can be used for expanding the application range of a similar material simulation experiment;
D. a reasonable protective layer mining scheme can be selected by simulating the mining of different protective layers, and the rationality and the scientificity of coal mining design are improved.
Drawings
FIG. 1 is a flow chart of a simulation method;
FIG. 2 is a schematic view of a similar simulation of upper shield mining;
FIG. 3 is a schematic view of a similar simulation of lower overburden mining.
Detailed Description
The present invention is further illustrated by the following examples, but it should not be construed that the scope of the above-described subject matter is limited to the following examples. Various substitutions and alterations can be made without departing from the technical idea of the invention and the scope of the invention is covered by the present invention according to the common technical knowledge and the conventional means in the field.
Example 1:
referring to fig. 1, the present embodiment discloses a pressure relief mining simulation method, which includes the following steps:
1) selecting different shape memory polymers as printing wires of the rock stratum, the protected layer and the protection layer.
The protective layer shape memory polymer comprises the following components in parts by weight: 20 parts of quartz sand, 10 parts of polyethylene, 30 parts of rubber, 10 parts of barite powder, 4 parts of gypsum, 10 parts of fine wood dust and 4-6 parts of paraffin.
The composition and the parts by mass of the protected shape memory polymer are as follows: 20 parts of quartz sand, 30 parts of barite powder, 10 parts of an expansion deformation agent, 6 parts of an antirust agent, 10 parts of aggregate and 4-6 parts of paraffin.
2) And 3D printing is carried out according to the geometric similar template of the rock coal layer to be printed, the structural similar model of the rock coal layer and the basic characteristics of each coal rock layer, strain gauges are respectively arranged at the interlayer positions of different rock layers so as to measure the deformation of the rock layers, and the 4D similar model of the stratum containing the protective layer block and the protected layer is obtained after the model is cooled. The basic characteristics of the coal rock stratum include volume weight, compressive strength, shear strength and the like.
3) The model is arranged on an optical bench. The protective layer blocks are gradually taken out from the stratum model to simulate the mining process of the protective layer, and the position, speed and range of the mining of the protective layer are controlled by the position, speed and number of the blocks. And (5) observing the processes of overburden rock fracture, overburden rock collapse, crack initiation and crack development in the mining process.
4) And putting the mined protective layer block into the model again, restoring the stratum to the original shape through external field stimulation, and healing the broken memory material.
5) And (5) repeating the step 3) and the step 4) to obtain the deformation damage condition of the protected layer under different protected layer mining conditions.
6) Obtaining the pressure relief and permeability increase range and effect of the protected layer under different protection layer mining conditions, and finally selecting the optimal protection layer mining scheme.
It is worth to be noted that the deformation amount of the protected layer is obtained by matching a dynamic crack detector with the acoustic emission device and the strain gauge. And estimating the expansion deformation rate of the protected layer through the strain gauge data. And obtaining the pressure relief and permeability increase range of the protective layer according to the monitoring data of the cracks and the fractures. The variation of the permeability characteristics is estimated by statistics of the number and propagation area, depth of cracks, fissures.
Example 2:
the embodiment discloses a pressure relief mining analog simulation method, which comprises the following steps:
1) according to the similarity ratio, the shape memory polymer is selected as the printing wire, and the selection and the proportion of the protective layer and the protected layer are different and need to be adjusted according to actual conditions.
2) And 3D printing is carried out according to the rock stratum geometric similar template to be printed, the rock stratum structure similar model and the basic characteristics of volume weight, strength and the like of each rock (coal) layer to obtain a stratum model comprising a protective layer block and a protected layer, and a 4D printing model is obtained after cooling. In the 3D printing process, mica powder is used as a separation material between stratums. The printing is carried out by repeatedly laminating the shape memory polymer from bottom to top.
3) The protective layer block is gradually taken out from the stratum model to simulate the mining process of the protective layer, and further simulate the deformation and damage process of the protective layer during the mining of the protective layer. Such as the crack initiation and development process, the fracture and collapse generation process, etc. The deformation of the protected layer can be obtained by matching a dynamic crack detector with an acoustic emission device and a strain gauge, and the penetration characteristic of the protected layer can be obtained. The expansion deformation rate of the protected layer is roughly calculated through strain gauges attached to all surfaces of the protected layer, the pressure relief and permeability increase range can be obtained according to monitoring data of cracks and fractures, and the change of permeability characteristics of the protected layer can be estimated through statistics of the number and the area of the cracks and the fractures.
4) And putting the mined protective layer block into the model again, restoring the stratum to the original shape through external field stimulation, and healing the broken memory material.
5) And (5) repeating the step 3) and the step 4) to obtain the range of the protected layer and the pressure relief and permeability increasing effects under different protection layer mining conditions, so that a more reliable protection layer mining scheme is obtained through comparison.
It should be noted that in the present embodiment, the different monitoring devices are arranged as follows: the strain gauge is attached to interfaces of different rock stratums and coal beds and the outer side face of each layer, at least 3 pairs of contacts of the acoustic emission monitoring equipment are respectively attached to the outer surfaces of the rock stratums and the coal beds so as to position cracks, the contacts of the dynamic crack monitor are also attached to the outer surfaces of the rock stratums and the coal beds, and only the contacts need to be attached to two adjacent side faces, and at least 3 contacts are needed to be attached to each side face.
Referring to fig. 2, the simulation method for the upper protective layer mining includes gradually taking out the upper simulated protective layer blocks, simulating the mining process of the protective layer, and observing the expansion deformation condition of the protected layer and the generation of damages such as other strata, protected cracks and fractures, so as to simulate the influence of the mined protective layer on the protected layer.
Example 3:
the embodiment discloses a pressure relief mining analog simulation method, which comprises the following steps:
1) and selecting the shape memory polymer as the printing wire according to the similarity ratio. The protective layer shape memory polymer comprises the following components in parts by weight: 20 parts of quartz sand, 10 parts of polyethylene, 30 parts of rubber, 10 parts of barite powder, 4 parts of gypsum, 10 parts of fine wood chips and 4-6 parts of paraffin; the composition and the parts by mass of the shape memory polymer to be protected are as follows: 20 parts of quartz sand, 30 parts of barite powder, 10 parts of an expansion deformation agent, 6 parts of an antirust agent, 10 parts of aggregate and 4-6 parts of paraffin. The shape memory polymer can uniformly absorb water and dehydrate without obvious water absorption deformation. After the protective layer simulation material is subjected to light or temperature excitation deformation, the mass or the volume of the protective layer simulation material can be uniformly contracted to one tenth or even one hundredth of the original mass or volume.
2) And 3D printing is carried out according to the rock stratum geometric similarity template to be printed and the geological structure similarity model to obtain a stratum structure model containing a protective layer block and a protected layer. In the 3D printing process, mica powder is used as a separation material between layers. The printing is carried out by repeatedly laminating the shape memory polymers from bottom to top by adopting a double-layer structure. Wherein, the double-layer structure is composed of materials with different proportions.
3) The process of overburden production is simulated by progressively removing overburden blocks from the earth model, wherein the location, rate and extent of overburden production is controlled by the location, rate and number of block removals. In the experimental process, the deformation condition of the protected layer can be obtained by matching the dynamic crack detector with the acoustic emission device and the strain gauge. The expansion deformation rate of the protected layer is roughly calculated through strain gauges attached to all surfaces of the protected layer, the pressure relief and permeability increase range can be obtained according to monitoring data of cracks and fractures, and the change of permeability characteristics of the protected layer can be estimated through statistics of the number and the area of the cracks and the fractures.
4) And putting the mined protective layer block into the model again, restoring the stratum to the original shape through external field stimulation, and healing the broken memory material.
5) And (5) repeating the step 3) and the step 4) to obtain the deformation and damage conditions of the protected layer under different protection layer mining conditions, thereby obtaining the pressure relief and permeability increase range and effect of the protection layer and selecting a more scientific and reasonable protection layer mining scheme.
It is worth noting that referring to fig. 3, in the present embodiment, a lower protective layer mining simulation experiment was performed, in which different monitoring devices are arranged as follows: the strain gauge is attached to interfaces of different rock stratums and coal beds and the outer side face of each layer, at least 3 pairs of contacts of the acoustic emission monitoring equipment are respectively attached to the outer surfaces of the rock stratums and the coal beds so as to position cracks, the contacts of the dynamic crack monitor are also attached to the outer surfaces of the rock stratums and the coal beds, and only the contacts need to be attached to two adjacent side faces, and at least 3 contacts are needed to be attached to each side face. Through the simulation experiment, the deformation conditions of the mined protective layers of different protective layers can be obtained after the relevant data are processed, so that a more scientific and reasonable protective layer mining scheme is preferred.
Claims (7)
1. A pressure relief mining analog simulation method is characterized by comprising the following steps:
1) selecting different shape memory polymers as printing wires of the rock stratum, the protected layer and the protective layer;
2) 3D printing is carried out according to the rock-coal layer geometric similarity template to be printed, the rock-coal layer construction similarity model and the basic characteristics of each coal rock layer to obtain a stratum similarity model comprising a protective layer block and a protected layer; wherein, the basic characteristics of the coal and rock stratum comprise volume weight, compressive strength and shear strength;
3) simulating a production process of the protective layer by progressively removing the protective layer from the earth model; the position, speed and range of the protective layer mining are controlled by the position, speed and number of the block bodies taken out; observing and simulating the processes of overburden rock fracture, overburden rock collapse, crack initiation and crack development in the mining process;
4) putting the mined protective layer block into the model again, restoring the stratum to the original shape by external field excitation, and simultaneously enabling the broken memory material to heal;
5) and (5) repeating the step 3) and the step 4) to obtain the deformation damage condition of the protected layer under different protected layer mining conditions.
2. The pressure relief mining simulation-alike method of claim 1, wherein: and 5) after the step 5), obtaining the pressure relief and permeability increase range and effect of the protective layer according to the deformation and damage conditions of the protected layer, and selecting an optimal protective layer mining scheme.
3. The pressure relief mining simulation-alike method of claim 1, wherein the protective layer shape memory polymer comprises the following components in parts by weight: 20 parts of quartz sand, 10 parts of polyethylene, 30 parts of rubber, 10 parts of barite powder, 4 parts of gypsum, 10 parts of fine wood chips and 4-6 parts of paraffin;
the composition and the parts by mass of the protected shape memory polymer are as follows: 20 parts of quartz sand, 30 parts of barite powder, 10 parts of an expansion deformation agent, 6 parts of an antirust agent, 10 parts of aggregate and 4-6 parts of paraffin.
4. The pressure relief mining simulation-alike method of claim 1, wherein: in the 3D printing process, mica powder is used as a separation material between layers.
5. The pressure relief mining simulation-alike method of claim 1, wherein: the healing of the broken memory material is controlled by illumination or temperature stimulation.
6. The pressure relief mining simulation-alike method of claim 1, wherein: the printing is carried out by repeatedly laminating the shape memory polymer from bottom to top.
7. The pressure relief mining simulation-alike method of claim 1, wherein: a strain gauge is attached to the protected layer; and a dynamic crack detector and an acoustic emission device are arranged outside the stratum similarity model.
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| CN113742940A (en) * | 2021-09-16 | 2021-12-03 | 重庆大学 | Mining pressure relief boundary space-time curve cluster determination method |
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