Soft coal body wall caving prevention method based on support pressure regulation and control

Abstract

The invention discloses a soft coal body wall caving prevention method based on support pressure regulation and control, and the method specifically comprises the following steps: according to a mining geology specification of a working face, preliminarily determining a fracture area and a damage area range of an advanced coal body; the method comprises the following steps: carrying out field observation on an advanced coal body of a to-be-mined soft coal seam working face by adopting a drilling peeping technology, and delimiting an accurate advanced coal body fracture area and damage area range in the soft coal seam working face; according to the observation result of the borehole peeping technology, the supports corresponding to the accurate advanced coal fracture area and the damage area and the adjacent supports are marked; when the support is moved during mining of the working face, the pressure of the marked support is increased through an electro-hydraulic control system of the support, so that the support belt is tightly pressed and attached to the direct top, and wiping plate movement of the support is achieved. The purposes of improving the stress state of the coal wall of the working face, shortening the acting time of the main roof rotation on the coal wall and reducing the damage degree of the coal wall are achieved.

Description

Technical Field

[0001] The present invention relates to the technical field of underground coal mining, and particularly relates to a method for preventing rib spalling of soft coal bodies based on support pressure regulation. Background Art

[0002] At present, there are mainly two methods for thick coal seam mining: top coal caving mining and full height mining in one pass with large mining height. Among them, the large mining height full height mining technology has been widely applied in recent years due to its advantages such as high resource recovery rate, low gangue content in the mined coal, relatively small coal dust and gas emission during the working face production.

[0003] However, since the theoretical research on large mining height mainly focuses on the conditions of stable roof and relatively hard coal seam, there is less research on the large mining height conditions of broken roof, soft coal quality, complex geological conditions and poor surrounding rock stability. Especially for the problem of rib spalling, with the increase of mining height, the problems of rib spalling and roof caving become increasingly prominent. The rib spalling depth of the coal wall in a large mining height fully mechanized working face can reach one meter or even several meters. After the rib spalling of the coal wall, the empty roof distance increases, causing end face leakage and caving, resulting in the deterioration of the roof conditions. The deterioration of the roof conditions leads to uneven stress on the supports. In severe cases, the supports may tilt or even collapse, affecting the advancing speed and safe mining of the working face. Rib spalling and roof caving have become the main obstacles restricting the safe and efficient production of large mining height working faces.

[0004] To solve the above problems, the method of grouting and strengthening the advanced coal wall is usually adopted to prevent rib spalling of the coal wall. However, this method only passively achieves the purpose of preventing rib spalling by changing the self-strength and integrity of the coal body. This method not only increases the mining cost, occupies the maintenance time, reduces the mining efficiency, but also fails to effectively play the production capacity advantage of the large mining height fully mechanized working face, greatly affecting the economic benefits of the coal mine.

[0005] Therefore, there is an urgent need for a method for preventing rib spalling of soft coal bodies based on support pressure regulation. Summary of the Invention

[0006] The present invention provides a method for preventing rib spalling of soft coal bodies based on support pressure regulation, which solves the problems such as serious rib spalling of the coal wall during the working face mining, increased roof control distance, end face leakage and caving, and deterioration of the roof conditions, and achieves the purpose of improving the stress state of the coal wall in the working face, reducing the action time of the main roof rotation on the coal wall and reducing the damage degree of the coal wall.

[0007] The present invention provides a method for preventing rib spalling of soft coal bodies based on support pressure regulation, which specifically includes the following steps:

[0008] According to the mining geological specification of the working face, preliminarily determine the scope of the geological structure of the working face, delimit the geological structure influence area, and preliminarily determine the scope of the advanced coal body fracture area and damage area;

[0009] Within the initially determined advanced coal body fracture zone and failure zone, borehole peephole technology is used to conduct on-site observations of the advanced coal body in the soft coal seam working face to be mined, and accurate ranges of the advanced coal body fracture zone and failure zone are demarcated within the soft coal seam working face;

[0010] According to the observation results of the borehole peephole technology, the supports corresponding to the accurate advanced coal body fracture zone and failure zone and the adjacent supports are marked;

[0011] When the supports are moved during the coal face mining, the pressure of the marked supports is increased through the electro-hydraulic control system of the supports, so that the supports closely fit the immediate roof under pressure to achieve the wiping plate movement of the supports, thereby weakening the coal wall pressure in the coal body fracture zone and failure zone in front of the supports and avoiding the shear failure of the coal wall caused by the broken roof.

[0012] For the method for preventing coal rib spalling of soft coal bodies based on support pressure regulation, preferably, the detection depth of the borehole peephole technology is not less than 100 m each time.

[0013] For the method for preventing coal rib spalling of soft coal bodies based on support pressure regulation, preferably, the soft coal seam working face is a large mining height working face of soft coal seam with "hard main roof - weak immediate roof".

[0014] For the method for preventing coal rib spalling of soft coal bodies based on support pressure regulation, preferably, the coal body fracture zone and failure zone include any one of faults, folds, weathered zones, subsidence columns, and breccia intrusion zones within the roadway geological structure belt area.

[0015] For the method for preventing coal rib spalling of soft coal bodies based on support pressure regulation, preferably, the number of the marked supports exceeds 2 - 3 frames of the supports within the range corresponding to the soft coal seam working face, the advanced coal body fracture zone and the failure zone.

[0016] For the method for preventing coal rib spalling of soft coal bodies based on support pressure regulation, preferably, the pressure of the marked supports is increased by more than 1500 KN - 2000 KN compared with the pressure of other surrounding supports.

[0017] For the method for preventing coal rib spalling of soft coal bodies based on support pressure regulation, preferably, it further includes the step: during the process of moving the supports in the coal face mining, when the electro-hydraulic control system of the supports detects that the working resistance of a certain support is significantly higher than the resistance of the surrounding supports and this support is not within the range of the marked supports, the pressure of the supports within this range is increased to ensure that the top of the supports closely fits the immediate roof to achieve the wiping plate movement of the supports.

[0018] The described method for preventing coal spalling in soft coal seams based on support pressure regulation preferably further includes the step: Before the face support is moved during coal mining, a top net is laid between the marked support and the adjacent unmarked support to prevent the floating gangue above the support roof beam from leaking out from the marked support and the adjacent unmarked support.

[0019] The beneficial effects are as follows:

[0020] 1. In the method of the present invention, when the support is moved during face coal mining, the support pressure of the supports corresponding to the coal seam fracture zone and the damaged zone is increased by using the electro-hydraulic control system, which improves the stress state of the face coal wall, reduces the action time of the main roof rotation on the coal wall, and reduces the damage degree of the coal wall.

[0021] 2. Compared with the method of grouting reinforcement in front of the coal wall to prevent coal wall spalling, the method of pressure regulation for the supports in the fracture zone and the broken zone can effectively control the roof subsidence in this area, avoid the shear failure of the coal wall caused by the broken roof, and has the characteristics of simple operation, cost saving, improved mining efficiency, high efficiency and reliability. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] The present invention will be further described below in conjunction with the drawings and embodiments.

[0023] Figure 1 is the plan view of the support pressure regulation of the present invention to prevent coal spalling;

[0024] Figure 2 is the sectional view A-A of the support pressure regulation of the present invention to prevent coal spalling.

[0025] In the figure:

[0026] 1. Geological structure influence area; 2. Precise range of the advanced coal seam fracture zone and damaged zone;

[0027] 3. Supports corresponding to the precise advanced coal seam fracture zone and damaged zone;

[0028] 6. Preliminary determination of the advanced coal seam fracture zone and damaged zone;

[0029] 7. Adjacent supports; 8. Immediate roof; 9. Main roof; 10. Face coal wall. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0030] To make the objectives, technical solutions and advantages of the present invention clearer, the technical solutions of the present invention will be clearly and completely described below in conjunction with the drawings. Obviously, the described embodiments are some but not all of the embodiments of the present invention. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the scope of protection of the present invention.

[0031] A method for preventing coal wall spalling in soft coal seams based on support pressure regulation specifically includes the following steps: According to the mining geological specification of the working face, preliminarily determine the scope of the geological structure of this working face, delimit the geological structure influence area, and preliminarily determine the scope of the advanced coal seam fracture area and damage area; Use borehole peephole technology to conduct on-site observation of the advanced coal seam in the soft coal seam working face to be mined, and delimit the accurate scope of the advanced coal seam fracture area and damage area within the soft coal seam working face; According to the observation results of the borehole peephole technology, mark the accurate soft coal seam working face, the supports corresponding to the advanced coal seam fracture area and damage area, and the adjacent supports; When the supports are moved during the mining of the working face, increase the pressure of the marked supports through the electro-hydraulic control system of the supports, so that the supports are tightly pressed against the immediate roof to achieve the wiping plate movement of the supports, so as to weaken the coal wall pressure in the coal seam fracture area and damage area in front of the supports and avoid the coal wall shear failure caused by roof fragmentation. The present invention achieves the purpose of improving the stress state of the coal wall in the working face, reducing the action time of the main roof rotation on the coal wall, and reducing the degree of coal wall damage.

[0032] The following takes a method for preventing coal wall spalling in soft coal seams based on support pressure regulation as an example to elaborate the entire technical process in detail.

[0033] Example 1

[0034] As Figure 1 and Figure 2 shown, in this example, the average thickness of the coal seam is 4.5 m, the dip angle is 6° - 31°, with an average of 16°, the endogenous fractures are developed, the coal seam is relatively soft, the working face has undulations along the strike, the working face is in uphill mining from the cutting hole to the stop line, and the length of the working face is 240 m. The immediate roof is siltstone, and the main roof is coarse-grained sandstone, belonging to a typical soft coal seam large mining height working face with "hard main roof - weak immediate roof". When this working face is mined, affected by roof fragmentation, relatively soft coal quality, and complex geological conditions, the problem of coal wall spalling and roof caving in this fully mechanized mining working face is very prominent. The depth of coal wall spalling can reach one meter or even several meters. After the coal wall spalls, the empty roof distance increases, causing end face leakage and caving, resulting in the deterioration of the roof conditions. The deterioration of the roof conditions leads to uneven stress on the supports. In severe cases, the supports will tilt or even collapse, affecting the advancing speed and safe mining of the working face.

[0035] A method for preventing coal wall spalling in soft coal seams based on support pressure regulation specifically includes the following steps:

[0036] S1: According to the mining geological specification of the working face, preliminarily determine the scope of the geological structure of this working face, delimit the geological structure influence area 1, and preliminarily determine the scope of the advanced coal seam fracture area and damage area 6.

[0037] Among them, the soft coal seam working face is a soft coal seam large mining height working face with "hard main roof 8 - weak immediate roof 9".

[0038] The coal seam fracture zone and failure zone include any one of faults, folds, weathered zones, subsidence columns, and breccia intrusion zones within the roadway geological structure zone.

[0039] S2: Within the preliminarily determined advanced coal seam fracture zone and failure zone, use borehole peephole technology to conduct on-site observation of the advanced coal seam of the soft coal seam working face to be mined, and demarcate the accurate advanced coal seam fracture zone and failure zone 2 within the soft coal seam working face.

[0040] Among them, the detection depth of the borehole peephole technology is not less than 100m each time.

[0041] S3: According to the observation results of the borehole peephole technology, mark the supports 3 corresponding to the accurate advanced coal seam fracture zone and failure zone and the adjacent supports 7.

[0042] Among them, the number of the marked supports exceeds 2 - 3 supports within the range corresponding to the soft coal seam working face, the advanced coal seam fracture zone and the failure zone.

[0043] S4: During the face mining and support moving process, increase the pressure of the marked supports through the electro-hydraulic control system of the supports, so that the supports closely fit the immediate roof 8 under pressure to achieve the scrubbing plate movement of the supports, so as to weaken the coal wall pressure in the coal seam fracture zone and failure zone in front of the supports and avoid the coal wall shear failure caused by the roof breakage.

[0044] Among them, the pressure of the marked supports should be increased by 1500KN - 2000KN more than the pressure of other surrounding supports.

[0045] S41: During the face mining and support moving process, when the electro-hydraulic control system of the supports detects that the working resistance of a certain support is significantly higher than that of the surrounding supports and this support is not within the range of the marked supports, increase the pressure of the supports within this range to ensure that the top of the supports closely fits the immediate roof 8 to achieve the scrubbing plate movement of the supports.

[0046] S42: Before the face mining and support moving, lay a top net between the marked supports and the adjacent unmarked supports to prevent the floating gangue above the support roof beams from leaking out from the marked supports and the adjacent unmarked supports.

[0047] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand that they can still modify the technical solutions described in the foregoing embodiments, or perform equivalent replacements for some of the technical features; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A method for preventing soft coal from spalling based on support pressure regulation, characterized in that: The specific steps include: According to the mining geological description of the working face, preliminarily determine the scope of the geological structure of the working face, delineate the geological structure influence area, and preliminarily determine the scope of the advanced coal body fracture area and the damage area; In the initially determined advanced coal body fracture zone and damage zone range, the advanced coal body of the soft coal seam working face to be mined is observed on site using the drilling peep technology, and the precise advanced coal body fracture zone and damage zone range is delineated in the soft coal seam working face; According to the observation results of the drilling peep technology, the supports corresponding to the advanced coal body fracture zone and the damage zone and the adjacent supports are accurately marked; When the frame is moved during mining at the working face, the pressure of the marked frame is increased through the electro-hydraulic control system of the frame, so that the frame belt is pressed tightly against the top to realize the movement of the wiper plate of the frame, so as to reduce the coal wall pressure in the coal body fissure area and the damage area in front of the frame, and avoid shear damage of the coal wall caused by the crushing of the roof.

2. The method for preventing soft coal from spalling based on support pressure regulation according to claim 1 is characterized in that: The drilling peek technology can detect a depth of no less than 100m each time.

3. The method for preventing soft coal from spalling based on support pressure regulation according to claim 2 is characterized in that: The soft coal seam working face is a soft coal seam high mining height working face with "hard basic roof and weak immediate roof".

4. The method for preventing soft coal from spalling based on support pressure regulation according to claim 3 is characterized in that: The coal body fissure zone and damage zone include any one of the faults, folds, weathering zones, collapse columns and breccia intrusion zones in the tunnel geological structure zone.

5. The method for preventing soft coal from spalling based on support pressure regulation according to claim 4 is characterized in that: The number of the marked supports exceeds 2-3 supports within the range corresponding to the soft coal seam working face, the advanced coal body fissure zone and the damage zone.

6. The method for preventing soft coal from spalling based on support pressure regulation according to claim 5 is characterized in that: The support pressure with the upward mark should exceed the pressure of other surrounding supports by 1500KN-2000KN.

7. The method for preventing soft coal from spalling based on support pressure regulation according to any one of claims 1 to 6, characterized in that: It also includes the following steps: during the working face recovery and frame moving process, the support's electro-hydraulic control system detects that the working resistance of a certain support is significantly higher than the resistance of the surrounding supports, and the support at that location is not within the marked support range, and the support pressure within that range is increased to ensure that the top of the support is in close contact with the top to achieve the support's wiper plate movement.

8. The method for preventing soft coal from spalling based on support pressure regulation according to claim 7 is characterized in that: The method also includes the following steps: before the working face is mined and the frame is moved, a top net is laid between the marked frame and the adjacent unmarked frame to prevent floating gangue above the frame top beam from leaking out from the marked frame and the adjacent unmarked frame.

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