CN104879127A - Method for replacing coal column by floor heaving top connecting - Google Patents

Abstract

The invention discloses a method for replacing a coal pillar with a bottom drum connected to the top, which is based on the characteristics of swelling or weak rock formations that are prone to bottom drums, and utilizes the characteristics of high ground pressure, high side pressure, high fragmentation and high expansion when encountering water to promote the mining area. expansion of the expansion or weak floor in the gob (4), take specific measures to bulge the expansion or weak floor (3) in the goaf (4) and make close contact with the roof (1) to achieve effective support, and then destroy the coal pillar ( 2) In the load-bearing core area, the load-bearing body is converted from the original coal pillar (2) into a bulging floor (3); after effective support, the original strip or room-and-pillar mining left coal pillars left in the mine underground are recovered (2). The method of replacing the coal pillar with the bottom drum connected to the top has a significant effect on improving the recovery rate of the water-expanding rock mass or the weak floor mine, and the production process is simple, and there is no need to set up other related equipment required for solid waste, paste or slurry filling. Investment, excavation and support costs are significantly reduced.

Description

A method of connecting the bottom drum to the roof to replace the coal pillar

technical field

The invention relates to a method for replacing a coal pillar underground in a coal mine, in particular to a method for replacing a coal pillar with a bottom drum connected to the roof in an underground coal mine, and belongs to the technical field of coal production.

Background technique

In the "three downs" of coal mining under water bodies, under buildings and under railways, in order to ensure that the surface settlement is within the standard range, strip mining is generally adopted. Strip mining is to divide the mined coal seam into several One strip is mined, one is left, and the remaining strip coal pillars are used to support the overlying strata to achieve the purpose of controlling surface subsidence.

According to statistics, after strip mining, more than 60% of the coal is pressed underground in the form of coal pillars, forming permanent coal pillars, resulting in waste of resources. Due to the increasing consumption of coal resources and the increasing demand of the national economy These coal pillars have been used as recycling objects, especially in areas where high-quality and scarce coal types are distributed in our country, and the development and mining efforts have been intensified.

However, due to the particularity and complexity of the conditions for the occurrence of this part of the coal pillar, it is required not to damage the ground facilities, nor to pollute the environment. Therefore, the newly developed coal pillar recovery technologies in recent years mainly include waste rock and other waste filling mining, and paste filling. Mining or strip caving area grouting filling to reduce settlement mining, etc., but the use of gangue and other waste, paste or grouting filling needs to transport the filling to the coal mine goaf or filling roadway, roadway excavation, filling material transportation and filling The high cost, many production links, complex procedures, and time-consuming and laborious, restrict the further popularization and application of related technologies.

Affected by the excavation engineering, the roadway roof, floor and the surrounding rocks of the two sides will deform and move into the roadway. The phenomenon that the roadway floor or the floor of the goaf rises upwards is called floor heave, which is a common occurrence in shafts and roadways. It is directly related to the nature of the surrounding rock, the influence of mining, the depth of mining and the geological structure. The bottom drum will deform the roadway and reduce the section, which will affect the ventilation and transportation and restrict the safe production of the mine, especially for " The re-mining of coal pillars in mines with "three down" soft rocks and water-swellable rock mass brings great difficulties.

Contents of the invention

In view of the above problems, the present invention provides a method for replacing coal pillars with a floor drum connected to the top, which is less costly and is suitable for coal pillar re-mining in mines with "three lower" soft rocks and water-swelling rock mass, and can realize effective support and resume mining.

In order to achieve the above-mentioned purpose, the method of replacing the coal pillar by connecting the bottom drum to the top is to use the characteristics of high ground pressure, high side pressure, high broken expansion and high water expansion to promote the coal pillar in the goaf according to the characteristics of swelling or weak rock strata that are easy to bottom out. After expanding the capacity of the bottom plate, the swelling or weak bottom plate in the goaf will bulge and come into close contact with the roof to achieve effective support, and recover the coal pillars left in the mine underground by the original strip or room-and-pillar mining. The specific steps as follows:

a. According to different situations such as ground building protection level, coal seam burial depth, coal seam mining height, and strip mining width, the empirical formula for column strength calculation is used to calculate the bearing capacity of coal pillars in different roadway mining schemes, and the coal pillars are analyzed by comparing the results. column stability;

b. Under the principle of ensuring that the coal pillar can effectively and safely carry the load, drill holes or cut grooves on the coal pillars, and the depth of the holes or cut grooves shall not exceed a quarter of the width of the coal room;

c. Make holes or cut grooves on the floor of the goaf between coal pillars, the depth of the holes or cut grooves shall not exceed a quarter of the width of the coal room;

d. After the floor in the goaf between the coal pillars bulges and comes into contact with the roof, propose a support design scheme for the bulging part of the roof and floor after mining. According to different conditions such as mining width and strip mining width, the empirical formula for column strength calculation is used to calculate the bearing capacity of the swelled bottom plate of different roadway mining schemes, and the stability of the swelled floor bearing column is analyzed by comparing the results;

e. When the strength of the swelled floor in the goaf between coal pillars reaches the required strength value, destroy the bearing core area of the coal pillar, release the high stress accumulated in the coal pillar due to the deformation of the roof and floor in the early stage, and load the main body Convert from the original coal pillar to a bulging floor;

f. After effective support is carried out according to the design requirements in step d, use coal mining equipment to mine and recover the coal pillar left in the underground mine when the original strip is used to mine the coal resources under the building.

As a further improvement of the present invention, the drilling or slotting in step b is at the middle of the vertical height of the coal pillar, and a plurality of holes or slots are distributed in a ring around the coal pillar.

As a further improvement of the present invention, after steps b and c, if the bulging bottom plate has not yet been connected to the top, add step c1: carry out surface vibration blasting on the bottom plate, and the depth of the blast hole shall not exceed a quarter of the width of the coal room .

As a further improvement of the present invention, step b1 is added after step b: under the principle of ensuring that the coal pillar can effectively and safely carry the load, perform surface vibration blasting on the coal pillar, and the depth of the blast hole does not exceed a quarter of the width of the coal room.

As a further improvement of the present invention, after steps b and c, if the swollen bottom plate has not yet been connected to the top, step c2 is added: injecting water into the water-swelling rock mass in the bottom plate.

As a further improvement of the present invention, the method for destroying the bearing core area of the coal pillar in step e is to drill holes on the coal pillar or inject water or loosen the dynamic gun.

As a further improvement of the present invention, the empirical formula for calculating column strength according to different situations such as ground building protection grade, coal seam burial depth, coal seam mining height, and strip mining width described in steps a and d is in the following table formula:

As a further improvement of the present invention, the coal mining equipment in the step f is a comprehensive mechanized shearer, or a comprehensive mechanized roadheader, or a combined mining machine, or a spiral shearer, or blasting equipment, or hydraulic cutting equipment .

Compared with the existing technology, the method of replacing the coal pillar with the bottom drum connected to the top uses specific measures to make the floor in the goaf bulge and closely contact with the roof to achieve effective support. High ground pressure and high stress promote the expansion of the floor under the stress deviation of the goaf. Therefore, for the "three down" soft rock and water-swelling rock mass mines, the floor in the goaf is completely bulged and tightly connected to the roof. After contacting and reaching a stable support strength, the coal pillars left in the underground mine when the original strip is mined for coal resources under the building can be completely recovered, with a high recovery rate; and the production process is simple, and no additional equipment is required to transport waste such as gangue and paste. The transportation equipment required for body or grouting filling greatly reduces the cost of excavation; at the same time, the expansion under the action of the bottom drum phenomenon and the stress deviation of the bottom plate fully utilizes the high stress of the bottom plate, and its supporting strength is high.

Description of drawings

Fig. 1 is a schematic diagram of the structure of the coal pillar supporting the overlying strata to control the surface subsidence;

Fig. 2 is the structural representation after punching or grooving on the coal pillar and the base plate;

Fig. 3 is a structural schematic diagram of the bulging top of the bottom plate under the action of high stress;

Fig. 4 is a schematic diagram of the structure when the bottom drum is effectively supported after the core area of the coal pillar is destroyed.

Fig. 5 is a schematic diagram of the structure after the coal pillar is fully recovered.

In the figure: 1. Roof, 2. Coal pillar, 3. Floor, 4. Goaf.

Detailed ways

The present invention will be further described below in conjunction with the accompanying drawings.

For the "three lower" mines with soft rock and water-swellable rock mass, as shown in Figure 1, the immediate floor is usually a weak rock formation (such as clay rock, etc.), and the permanent coal pillar 2 and roof 1 to be mined are usually relatively complete , under the compression molding effect and stress of the two permanent coal pillars 2, the soft and broken floor 3 rock strata located in the entire goaf 4 will squeeze and flow into the goaf 4, especially for deep mines. The ground pressure rises, and the high ground pressure zone and high stress make the expansion under the stress deviation of the floor 3 in the goaf 4 more obvious, and the floor heave is more obvious.

As shown in Fig. 2 to Fig. 5, the method of replacing the coal pillar with the bottom drum is based on the characteristics of swelling or weak rock strata that are prone to bottom drum, and utilizes the characteristics of high ground pressure, high side pressure, high fragmentation and high swelling when encountering water. The expanded or weak bottom plate 3 in the goaf 4 is expanded, and specific measures are taken to make the expanded or weak bottom plate 3 in the goaf 4 bulge and come into close contact with the roof 1 to achieve effective support, and then recover the original strip or The coal pillar 2 left in the mine underground by room and pillar mining, the specific steps are as follows:

a. According to different situations such as ground building protection level, coal seam burial depth, coal seam mining height, and strip mining width, the empirical formula for column strength calculation is used to calculate the bearing capacity of coal pillars in different roadway mining schemes, and the coal pillars are analyzed by comparing the results. column stability;

b. Under the principle of ensuring that the coal pillar 2 can effectively and safely carry the load, drill holes or cut grooves on the coal pillar 2. The depth of the holes or cut grooves shall not exceed a quarter of the width of the coal room, and remove the two sides of the coal pillar 2. The deformation of the bottom plate 3 is restricted by the coal body within the depth of the hole, and at the same time, the load transmitted from the roof 1 is concentrated to the bearing area of the coal pillar 2, which increases the stress transmitted by the coal pillar 2 to the bottom plate 3 and causes the bottom plate 3 to bulge more violently. rise;

c. Drill holes or cut grooves on the floor 3 of the goaf 4 between the coal pillars 2, the depth of the holes or grooves shall not exceed 1/4 of the width of the coal room, and destroy the restrictive effect of the surface layer of the floor 3 on the floor drum , causing stress concentration in the bottom plate 3, promoting the development of the original cracks, and the bottom plate 3 expands and bulges under the action of the stress deviation;

d. After the floor 3 in the goaf 4 between the coal pillars 2 bulges and comes into contact with the roof 1, propose a support design scheme for the bulging part of the roof and floor after mining, according to the protection level of the ground buildings and the depth of the coal seam For different situations such as coal seam mining height and strip mining width, the empirical formula for column strength calculation is used to calculate the bearing capacity of the swollen floor 3 of different roadway mining schemes, and the stability of the bulged floor 3 bearing column is analyzed by comparing the results. sex;

e. When the strength of the bulging floor 3 in the goaf 4 between the coal pillars 2 reaches the required strength value, take measures to destroy the bearing core area of the coal pillar 2, and release the accumulation in the coal pillar 2 due to the deformation of the roof and floor in the early stage High stress, the load-bearing body is converted from the original coal pillar 2 to the bulging bottom plate 3;

f. Carry out support according to the design requirements in step d, and use the coal mining equipment to mine and reclaim the coal pillar 2 left in the underground when the coal resources under the building are mined in the original strip;

In the process of mining and recovering the coal pillar 2, the advancing speed of the working face is well controlled so that the peak position of the leading pressure not only intensifies the swelling of the bottom plate, but also makes the coal wall of the working face in the leading pressure drop zone, without high stress and large deformation.

In order to further effectively remove the constraint of the coal body on the deformation of the bottom plate 3 within the depth range of the holes on both sides of the coal pillar 2, and at the same time effectively concentrate the load transmitted from the roof 1 to the bearing area of the coal pillar 2, as a further improvement of the present invention, the The position of the perforation or slotting in the above step b is at the middle position of the vertical height of the coal pillar 2, and a plurality of holes or grooves are distributed around the coal pillar 2 in a ring shape.

In order to enable the bottom plate 3 to quickly release the internal stress and quickly bulge, as a further improvement of the present invention, after steps b and c, if the bulging bottom plate 3 has not been connected to the top, then add step c1: surface layer of the bottom plate 3 Vibration blasting, the depth of the blast hole does not exceed a quarter of the width of the coal room, further releasing the internal stress quickly.

In order to increase the stress transfer effect of the coal pillar 2 to the core area, step b1 is added after step b: Under the principle of ensuring that the coal pillar 2 can effectively and safely carry the load, carry out surface vibration blasting on the coal pillar 2, and the depth of the blast hole does not exceed the coal pillar 2. a quarter of the width of the room.

The effect of water can reduce the friction between rock bedding, joints and fissures, reduce the overall connection strength of the rock, make the rock mass form a slip surface along the joint surface, bedding surface and fissure surface of the rock layer, and separate the original layer The closely connected rock mass is divided into many thin layers, and even completely loses strength, and some mineral components in the rock expand when they encounter water. Therefore, in order to further accelerate the swelling speed of the bottom plate 3, as a further improvement of the present invention, After steps b and c, if the swollen bottom plate 3 has not yet been connected to the top, add step c2: inject water into the water-swellable rock mass in the bottom plate 3 .

In order to quickly destroy the load-bearing core area of the coal pillar 2 and release the high stress accumulated in the coal pillar 2 due to the deformation of the roof and floor 3 in the previous stage, as a further improvement of the present invention, the load-bearing core area of the coal pillar 2 is destroyed in the step e. The best measure is to perforate or inject water or loosen the moving gun on the coal pillar 2.

In order to more accurately calculate the bearing capacity of coal pillar 2 or floor 3 during different roadway mining schemes, as a further improvement of the present invention, according to the protection level of ground buildings, coal seam burial depth, coal seam mining height, The empirical formula for column strength calculation in different situations such as strip mining width is the formula in the following table:

In order to safely and efficiently recover the mining coal pillar 2, as a further improvement of the present invention, the coal mining equipment in the step f is a comprehensive mechanized coal mining machine, or a comprehensive mechanized roadheader, or a combined mining machine, or a screw mining machine. Coal machines, or blasting equipment, or hydraulic cutting equipment.

The method of connecting the bottom drum to the roof to replace the coal pillar is to use the bottom drum phenomenon, high ground pressure, high The stress promotes the expansion of the bottom plate 3 in the goaf 4 under the action of the stress deviation. Therefore, for the “three down” soft rock and water-swelling rock mass mines, the bottom plate 3 in the goaf 4 is completely bulged and the roof 1 After being in close contact and reaching a firm support strength, as shown in Figure 5, the coal pillar 2 left in the underground mine when the original strip mining coal resources under the building can be completely recovered, and the recovery rate is high; and the production process is simple, no additional Setting up conveying equipment required for conveying waste such as gangue, paste or grouting filling greatly reduces the cost of excavation; at the same time, using the floor drum phenomenon and the expansion under the stress deviation of the bottom plate 3 is to fully utilize the high stress of the bottom plate 3 , and its support strength is high.

Claims (8)

1. A method for replacing a coal pillar with a floor drum connected to the top, characterized in that, according to the characteristics of swelling or weak rock strata that are easy to drum, the characteristics of high ground pressure, high side pressure, high broken swell and high water swell are utilized to promote mining The bottom plate (3) in the goaf (4) is expanded so that the expansion or weak bottom plate (3) in the goaf (4) is bulged and closely contacted with the top plate (1) to achieve the effect of effective support, and the original For the coal pillar (2) left in the mine underground by strip or room-and-pillar mining, the specific steps are as follows: a. According to different situations such as ground building protection level, coal seam burial depth, coal seam mining height, and strip mining width, the empirical formula for column strength calculation is used to calculate the bearing capacity of coal pillars in different roadway mining schemes, and the coal pillars are analyzed by comparing the results. column stability; b. Under the principle of ensuring that the coal pillar (2) can effectively and safely carry the load, drill holes or cut grooves on the coal pillar (2), and the depth of the holes or cut grooves shall not exceed a quarter of the width of the coal room; c. Punch or cut holes on the floor (3) of the goaf (4) between the coal pillars (2), the depth of the holes or cut grooves shall not exceed a quarter of the width of the coal room; d. After the bottom plate (3) in the goaf (4) between the coal pillars (2) bulges and comes into contact with the roof (1), propose a support design scheme for the bulging parts of the roof and bottom plate after mining, and according to Based on different conditions such as ground building protection level, coal seam burial depth, coal seam mining height, strip mining width, etc., the empirical formula for column strength calculation is used to calculate the bearing capacity of the swelled bottom plate (3) of different roadway mining schemes. Through the comparison of the results, Analyze the stability of the bulging bottom plate (3) bearing column; e. When the strength of the bulging floor (3) in the goaf (4) between the coal pillars (2) reaches the required strength value, the bearing core area of the coal pillar (2) is destroyed, and the deformation of the roof and floor due to the previous stage is released. The high stress accumulated in the coal pillar (2) transforms the bearing body from the original coal pillar (2) into a bulging floor (3); f. After performing effective support according to the design requirements in step d, use coal mining equipment to mine and recover the coal pillars (2) left in the underground when the original strip is used to mine the coal resources under the building. 2. The method for connecting the bottom drum to the top of claim 1 to replace the coal pillar, characterized in that the position of the perforation or grooving in the step b is in the middle of the vertical height of the coal pillar (2), A plurality of holes or slots are annularly distributed around the coal pillar (2). 3. The method for connecting the bottom drum to the roof to replace the coal pillar according to claim 1, characterized in that, after steps b and c, if the bulged bottom plate (3) has not yet been connected to the top, then increase the c1 step: the bottom plate (3) Conduct surface vibration blasting, and the depth of the blast hole shall not exceed 1/4 of the width of the coal room. 4. The method for connecting the bottom drum to the top of claim 1 to replace the coal pillar is characterized in that, after the step b, the b1 step is added: under the principle that the coal pillar (2) can be effectively and safely carried, the coal pillar ( 2) Vibration blasting is carried out on the surface, and the depth of the blast hole shall not exceed a quarter of the width of the coal room. 5. The method for connecting the bottom drum to the roof according to claim 1 to replace the coal pillar is characterized in that, after steps b and c, if the bulging bottom plate (3) has not been connected to the top yet, then step c2 is added: The water-swellable rock mass in (3) is injected with water. 6. The method for connecting the bottom drum to the top of claim 1 to replace the coal pillar is characterized in that, in the step e, the method for destroying the bearing core area of the coal pillar (2) is to punch the coal pillar (2) Hole or inject water or loosen and move cannon. 7. The method according to claim 1, wherein the bottom drum is connected to the roof to replace the coal pillar, characterized in that, according to the protection level of ground buildings, coal seam burial depth, coal seam mining height, and strip mining width described in steps a and d, The empirical formula for calculating column strength in different situations is the formula in the following table: 8. The method for connecting the bottom drum to the top of claim 1 to replace the coal pillar, characterized in that the coal mining equipment in the step f is a comprehensive mechanized coal shearer, or a comprehensive mechanized roadheader, or a combined mining machine , or auger, or blasting equipment, or hydraulic cutting equipment.