Method for modifying overburden of steeply inclined and super-thick coal seam

Abstract

The present application provides a steeply inclined thick coal seam overburden modification method, comprising: obtaining coal seam mining parameters according to the geological overburden conditions and physical and mechanical parameters of the steeply inclined thick coal seam; performing three-dimensional modeling according to the coal seam mining parameters, and constructing an energy field distribution law diagram of the steeply inclined thick coal seam overburden on the three-dimensional model according to the positioning of each microseismic event and the released energy in the mining process of the steeply inclined thick coal seam overburden; drawing the total area of energy release, as well as the low-energy area and high-energy area in the total area on the energy field distribution law diagram; sequentially connecting the position of the mining working face with the low-energy area and the high-energy area in the total area to obtain a microseismic aggregation path, which is the energy conduction and release path under mining disturbance; and developing modification measures for the low-energy area, the high-energy area and the microseismic aggregation path. The present application solves the technical problems of high engineering implementation cost and complex process in the prior art.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of coal, in particular to a method for modifying overburden of steeply inclined and super-thick coal seam. BACKGROUND

[0002] In recent years, with the increase of mining depth, dynamic disasters occur more frequently in the process of mining steeply inclined and super-thick coal seam. The frequent dynamic disasters cause serious economic losses and seriously restrict the safety production of the mine. The mining of the working face causes the breakage of the overburden of the steeply inclined and super-thick coal seam. When the overburden breaks, it releases a huge amount of energy. The energy conducted from the seismic source to the mining space and the elastic energy accumulated in the surrounding coal and rock mass exceed the minimum energy required for the destruction of the coal and rock mass, and the dynamic disaster phenomenon occurs. With the increase of mining depth, the stress environment of mining operation increases. Under the condition of new mining depth and high stress, it is urgent to solve the problem of dynamic disaster control in steeply inclined and super-thick coal seam.

[0003] The existing dynamic disaster prevention and control technology mainly prevents and controls disasters from the perspective of pressure relief. With the increase of mining depth, under the condition of high stress environment, the traditional pressure relief prevention and control technology has poor disaster control effect, and it is difficult to ensure the safety of mining under the new mining depth. The existing dynamic disaster prevention and control technology has the phenomenon of excessive prevention and control. All overburden is blasted, the construction cost is high, and it may cause excessive fragmentation of the roadway and cause new support problems. SUMMARY

[0004] Based on the above problems, the present application provides a method for modifying the overburden of steeply inclined and super-thick coal seam, which solves the technical problems of high engineering implementation cost, complex process and low work efficiency in the prior art.

[0005] The present application provides a method for modifying the overburden of steeply inclined and super-thick coal seam, which comprises:

[0006] obtaining coal mining parameters according to the geological overburden conditions and physical and mechanical parameters of the steeply inclined and super-thick coal seam;

[0007] performing three-dimensional modeling according to the coal mining parameters, and constructing an energy field distribution law diagram of the overburden of the steeply inclined and super-thick coal seam on the three-dimensional model according to the positioning of each microseismic event and the energy released in the mining process of the overburden of the steeply inclined and super-thick coal seam;

[0008] drawing the total area of energy release, and the low-energy area and high-energy area in the total area on the energy field distribution law diagram;

[0009] connecting the position of the mining working face with the low-energy area and the high-energy area in the total area in sequence to obtain a microseismic aggregation path, the microseismic aggregation path being the conduction and release path of energy under mining disturbance;

[0010] The modification measures are carried out on the low-energy area, the high-energy area and the microseismic gathering path.

[0011] In addition, the modification measure carried out on the high-energy area is deep-hole blasting.

[0012] In addition, the deep-hole blasting is to drill and charge holes respectively on the left lower side and the right lower side of the coal body of the steeply inclined and super-thick coal seam.

[0013] In addition, when drilling the holes respectively on the left lower side and the right lower side, first, the drilling points are selected, and then one deep hole is drilled respectively to the left and to the right with the extension line of the drilling point as the reference, and the angle of the two deep holes is 10 degrees.

[0014] In addition, the modification measures carried out on the low-energy area and the microseismic gathering path are shallow blasting.

[0015] In addition, the shallow blasting is to drill and charge holes respectively on the left lower side and the right lower side of the coal body, and three shallow holes are drilled on each side, and the angle difference between every two shallow holes is greater than or equal to 15 degrees.

[0016] In addition, the length of the shallow hole is one half of the length of the deep hole.

[0017] In addition, the included angles of the two deep holes with the horizontal plane are 25 degrees and 35 degrees respectively;

[0018] The included angles of the three shallow holes with the horizontal plane are 25 degrees, 45 degrees and 60 degrees respectively.

[0019] In addition, before blasting, the middle part of the rock pillar between the two roadways is water injected.

[0020] In addition, the length of the water injection hole for water injection is 135 m, and the angle is 6 degrees.

[0021] The present application solves the technical problems of high engineering implementation cost, complex process and low operation efficiency in the prior art. The problems are solved by accurately positioning the power disaster energy release source, and modification measures are carried out on the low-energy area, the high-energy area and the microseismic gathering path, so that low-cost disaster prevention and control is realized. BRIEF DESCRIPTION OF DRAWINGS

[0022] Figure 1 The flow chart of the method for calculating the working resistance of the hydraulic support provided by one embodiment of the present application is shown in the figure;

[0023] Figure 2 The schematic diagram of the energy field distribution law provided by one embodiment of the present application is shown in the figure;

[0024] Figure 3 The schematic diagram of the mining stress path provided by one embodiment of the present application is shown in the figure;

[0025] Figure 4The schematic diagram of steeply inclined and super-thick coal seam mining is provided for one embodiment of the present application;

[0026] Figure 5 The working face coal seam hard roof and floor deep hole blasting construction plan view is provided for one embodiment of the present application;

[0027] Figure 6 The working face coal seam roof and floor deep hole blasting construction elevation view is provided for one embodiment of the present application;

[0028] Figure 7 The working face coal seam roof and floor shallow blasting hole construction plan view is provided for one embodiment of the present application;

[0029] Figure 8 The working face coal seam roof and floor shallow blasting hole construction plan view is provided for one embodiment of the present application;

[0030] Figure 9 The rock pillar chamber water injection layout plan view is provided for one embodiment of the present application;

[0031] Figure 10 The rock pillar chamber water injection layout elevation view is provided for one embodiment of the present application. DETAILED DESCRIPTION

[0032] The present application is further described in detail below in conjunction with specific embodiments and drawings. It is only intended to illustrate the specific embodiments of the present application, and does not have any limitation on the present application, and the protection scope of the present application is subject to the claims.

[0033] Reference Figure 1 and Figure 4 The present application proposes a method for calculating the working resistance of a hydraulic support, comprising:

[0034] Step S001, obtaining coal seam mining parameters according to the geological overburden conditions and physical and mechanical parameters of the steeply inclined and super-thick coal seam;

[0035] Step S002, performing three-dimensional modeling according to the coal seam mining parameters, and constructing an energy field distribution law diagram of the steeply inclined and super-thick coal seam overburden rock on the three-dimensional model according to the positioning of each microseismic event and the released energy in the mining process of the steeply inclined and super-thick coal seam overburden rock;

[0036] Step S003, drawing the total area of energy release, and the low energy area and the high energy area in the total area on the energy field distribution law diagram;

[0037] Step S004, sequentially connecting the position of the mining working face with the low energy area and the high energy area in the total area to obtain a microseismic aggregation path, and the microseismic aggregation path is the energy conduction and release path under mining disturbance;

[0038] Step S005, the low energy area, high energy area and microseismic aggregation path are carried out modification measures.

[0039] The existing acute inclination dynamic disaster prevention technology mainly develops from the ideas of rock mass pressure relief and coal mass pressure relief. The rock mass is carried out blasting and water injection, and the coal mass is carried out water injection pressure relief measures. The implementation measures are aimed at the whole rock mass and coal mass. The engineering implementation cost is high, the process is relatively complex, and the operation efficiency is low. The existing dynamic disaster prevention technology does not consider the accurate positioning of the energy release source and the conduction path, and cannot realize the accurate implementation of the dynamic disaster prevention and control technology measures.

[0040] In step S001, the coal seam mining parameters are obtained according to the geological overburden conditions and physical and mechanical parameters of the acute inclined thick coal seam.

[0041] The geological overburden conditions are, for example, that the coal seam inclination of the acute inclined thick coal seam is more than 45 degrees, the thickness is 20-50m, and the horizontal sectional fully mechanized caving mining is adopted.

[0042] The physical and mechanical parameters include the density, uniaxial compressive strength, Poisson's ratio, elastic modulus, void, water absorption and the like of the coal seam.

[0043] The coal seam mining parameters include the coal seam thickness, working face width, coal cutter cutting height and coal caving height, working face advancing speed, mining layout, mining sequence and the like.

[0044] The coal seam mining parameters are obtained according to the geological overburden conditions and physical and mechanical parameters of the inclined thick coal seam. For example:

[0045] Generally, the coal seam mining parameters are designed according to the overburden conditions and related physical and mechanical parameters of the coal seam. Since the coal seam is thick, top coal caving mining is adopted. The thick coal seam leads to the difficulty of top coal caving, and certain top coal weakening measures need to be taken. The working face width is generally the horizontal width of the coal seam, and the working face advancing speed is designed to meet the mine production capacity.

[0046] For example, taking the Wudong Coal Mine of the State Energy Group Xinjiang Energy Co., Ltd. as an example, the B3-6 coal seam of the Wudong Coal Mine is stably deposited, which is a monocline structure with simple structure. There is no large fault or magmatic intrusion phenomenon in the mining area. The average thickness of the B3-6 coal seam is 43.5 meters, the inclination is 86°-87°, the average inclination is 87°, the strike is between N58°-60°, and the whole minefield range is stable and can be mined. The main mining faces include: +475 horizontal fully mechanized caving face, +450 horizontal fully mechanized caving face, +425 horizontal fully mechanized caving face, +400 horizontal fully mechanized caving face and the like.

[0047] The +475 working face mining level is +475m level, the designed strike length is 2520m, the working face designed recoverable length is 2260m, the working face safety coal pillar is 260m, the working face designed length is 43m, and the working face stage height is 25m. The average layering height of the working face is 25m, the machine mining is 3m, the top coal caving is 22m, the mining to caving ratio is 1:7.33. The coal cutter cutting depth is 0.8m, the caving step is 1.6m, the working face daily advance is 7.2m. The working face recoverable reserves is 2810932t, the designed recovery rate is 79.82%, the working face production capacity is 264.03 million t / a, and the service life of the working face is about 1.07 years. In summary, the service life of the +475B3+6 coal seam fully mechanized caving face is 12.8 months.

[0048] In step S002, three-dimensional modeling is performed according to the coal seam mining parameters, and an energy field distribution law diagram of the overburden rock of the steeply inclined and thick coal seam is constructed according to the positioning of each microseismic event and the released energy in the three-dimensional modeling during the mining process of the overburden rock of the steeply inclined and thick coal seam.

[0049] Generally, the three-dimensional model is constructed according to the buried depth of the working face, the thickness and lithology of the overburden rock, the thickness and related physical and mechanical parameters of the coal seam, the inclination angle, the mining thickness of the working face, and the advancing speed of the working face, and the energy field distribution law of the overburden rock under mining disturbance is analyzed.

[0050] In step S003, the total area of energy release, and the low-energy area and the high-energy area in the total area are drawn on the energy field distribution law diagram.

[0051] The energy field distribution law diagram includes the distribution range, value and position of the energy in the spatial plane, such as Figure 2 The energy field distribution during the coal seam mining process is shown.

[0052] According to the energy field distribution law diagram, it can be clearly seen which area has a larger energy value, so it can be determined that the larger the energy value, the greater the possibility of dynamic disaster occurrence. It is used to accurately identify the potential area of disaster occurrence, and provide a clear implementation position for the implementation of disaster control measures. At the same time, according to the size of the energy value, the risk of dynamic disaster occurrence is further analyzed. The larger the energy value, the greater the possibility of occurrence, and the greater the need for fast and large-scale implementation of disaster control measures; the smaller the energy value, the smaller the possibility of dynamic disaster occurrence, and smaller intensity of pressure relief disaster control measures can be taken, and the dynamic changes of the energy field distribution need to be monitored.

[0053] The occurrence position of the microseismic event is the three-dimensional coordinates of each microseismic event calculated by the microseismic monitoring system according to the time difference of the vibration signals received by multiple microseismic sensors through coordinate conversion, so as to obtain the occurrence position of the microseismic event.

[0054] Through positioning and energy calculation of each microseismic event in the mining process, an energy field distribution cloud chart of the microseismic event is drawn, the relationship between the high energy value area and the mining position is analyzed according to the position of the mining working face, the total area of energy release under mining disturbance, the low energy area and the high energy area are outlined, the position of the mining working face is sequentially connected with the low energy area and the high energy area in the total area, which is the microseismic aggregation route, and the path is the energy conduction and release path under mining disturbance.

[0055] As shown in Figure 2 The area in the circle pointed by the arrow in the figure is a high energy area, and the white dotted line is the curve of the position of the mining working face sequentially connected with the low energy area and the high energy area in the total area, which is the energy conduction and release path under mining disturbance.

[0056] In step S004, the position of the mining working face is sequentially connected with the low energy area and the high energy area in the total area to obtain the microseismic aggregation path, and the microseismic aggregation path is the energy conduction and release path under mining disturbance.

[0057] Through positioning and energy value calculation of each microseismic event in the mining process, an energy field distribution cloud chart is drawn, the cloud chart is dynamically updated, changes continuously with the advancement of the working face, the energy value standard changes according to the degree of mining disturbance and the geological conditions, and generally, the energy value of a single microseismic event of the coal mining working face is 100000 Joules, and the energy value of a single microseismic event of the tunneling working face is 10000 Joules. In the cloud chart drawing, the energy distribution characteristics of each microseismic event in the spatial grid are uniformly calculated according to the interpolation algorithm, a suitable interpolation algorithm is selected according to the mining characteristics and the stratum structure, and generally, the cubic polynomial high-order interpolation algorithm is more accurate. If the energy value is concentrated in a certain area under some conditions, such as a fault or a fold, a linear interpolation algorithm can be used according to the situation.

[0058] The stress path under mining disturbance is described, and in addition to the unit calculation and analysis of the microseismic event, the mining stress path analysis can also be used, that is Figure 3 The area contained in the curve in the middle of the figure, the energy conduction path in the energy field distribution and the mining stress path are fused and analyzed, the accuracy of the energy conduction path result is improved, and scientific support is provided for the determination of the disaster control position.

[0059] The present application solves the technical problems of high engineering implementation cost, complex process and low work efficiency in the prior art, and solves the problems by accurately positioning the energy release source of the dynamic disaster, and carries out modification measures on the low energy area, the high energy area and the microseismic aggregation path, thereby realizing low-cost disaster prevention and control.

[0060] In one of the embodiments, the modification measure carried out on the high-energy area is deep-hole blasting.

[0061] As shown in Figure 5 and 6 , implementing deep-hole blasting modifies the overburden of the energy release source of the dynamic disaster, reduces energy accumulation, and thus achieves the purpose of eliminating the source.

[0062] In one of the embodiments, the deep-hole blasting is drilling and charging holes on the left lower side and the right lower side of the coal body of the steeply inclined and super-thick coal seam respectively. As shown in Figure 5 , the overburdens on both sides of the coal body are blasted.

[0063] This embodiment finds out the energy source and the conduction path of the dynamic disaster, reduces the prevention and control cost of the dynamic disaster measure implementation based on the precise prevention and control technology of the idea of eliminating the source and weakening the conduction to prevent and control the dynamic disaster, realizes the goal of precise prevention and control of the dynamic disaster, improves the sustainability of the working face production, and speeds up the advancing speed. The personnel and equipment safety in the mining space are ensured.

[0064] The angle of the hole can be selected according to the actual situation and is not limited.

[0065] In one of the embodiments, when drilling holes on the left lower side and the right lower side respectively, first, a drilling point is selected, and then a deep hole is drilled to the left and right respectively based on the extension line of the drilling point, and the angle of the two deep holes is different by 10 degrees. When drilling, a drilling point is selected, and then a deep hole is drilled to the left and right respectively based on the extension line of the drilling point, and the effect of blasting is better through multiple holes. The angle of the two deep holes can also be different by other degrees.

[0066] As shown in Table 1:

[0067] Table 1 Deep-hole blasting hole parameter table of the working face coal seam roof and floor

[0068]

[0069] As shown in Figure 7 and 8 , in one of the embodiments, the modification measure carried out on the low-energy area and the microseismic gathering path is shallow blasting.

[0070] The low-energy area and the microseismic gathering path are subjected to shallow blasting to weaken the energy conduction path.

[0071] In one of the embodiments, the shallow blasting is drilling and charging holes on the left lower side and the right lower side of the coal body respectively, and three shallow holes are drilled on each side, and the angle difference between every two shallow holes is greater than or equal to 15 degrees.

[0072] As shown in Table 2:

[0073] Table 2 Working face coal seam roof and floor shallow blasting hole parameter table

[0074]

[0075] In one embodiment, the length of the shallow hole is half of the length of the deep hole.

[0076] The length of the shallow hole is designed to be half of the length of the deep hole, that is, the respective blasting requirements can be met.

[0077] In one embodiment, the angles of the two deep holes with the horizontal plane are 25 degrees and 35 degrees, respectively.

[0078] The angles of the three shallow holes with the horizontal plane are 25 degrees, 45 degrees and 60 degrees, respectively. The angles of the two deep holes with the horizontal plane are not fixed and can be 25 degrees and 35 degrees, or other degrees. The angles of the three shallow holes with the horizontal plane can be 25 degrees, 45 degrees and 60 degrees, respectively, or other degrees.

[0079] By designing the angle between every two holes, the overburden blasting is more complete.

[0080] Referring to Figure 9 and 10 In one embodiment, the middle part of the rock pillar between the two roadways is watered before blasting.

[0081] Before blasting, the energy release source, that is, the high energy area and the energy conduction path, is watered. Since there is high-intensity siltstone in the middle part of the rock pillar near the B2 roadway side at +450 level, and the B2-B3 rock pillar, in order to prevent energy accumulation of the B2-B3 rock pillar, a water injection and pressure relief project is carried out in the stone door process roadway constructed on the side of the roof of the B2 roadway.

[0082] In one embodiment, the length of the water injection hole for water injection is 135m and the angle is 6 degrees. As shown in Table 3:

[0083] Table 3 B2-B3 rock pillar stone door water injection hole parameter table

[0084]

[0085] This embodiment avoids energy accumulation of the rock pillar.

[0086] The above only describes the principles and preferred embodiments of the present application. It should be noted that, for those skilled in the art, on the basis of the principles of the present application, a number of other variations can also be made, which should also be considered as the protection scope of the present application.

Claims

1. A method for modifying the overburden of steeply dipping, extra-thick coal seams, characterized in that, include: The coal seam mining parameters are obtained based on the geological overburden conditions and physical and mechanical parameters of the steeply inclined extra-thick coal seam. Based on the coal seam mining parameters, a three-dimensional model is constructed, and based on the actual location and energy release of each microseismic event during the mining of steeply inclined and extra-thick coal seam overburden, an energy field distribution pattern diagram of the steeply inclined and extra-thick coal seam overburden is constructed on the three-dimensional model. Draw the total area of ​​energy release, as well as the low-energy and high-energy areas within the total area, on the energy field distribution diagram; By sequentially connecting the location of the mining face with the low-energy and high-energy areas in the total area, a microseismic accumulation path is obtained. The microseismic accumulation path is the transmission and release path of energy under mining disturbance. Modification measures were implemented for low-energy regions, high-energy regions, and microseismic accumulation paths; The modification measures carried out in the high-energy region are deep-hole blasting; Deep-hole blasting involves drilling holes and loading explosives on the lower left and lower right sides of a steeply inclined, extra-thick coal seam.

2. The method for modifying the overburden of steeply dipping, extra-thick coal seams according to claim 1, characterized in that, When drilling holes on the lower left and lower right sides, first select the drilling point, and then drill a deep hole to the left and a deep hole to the right respectively, with the angle of the two deep holes differing by 10 degrees.

3. The method for modifying the overburden of steeply dipping, extra-thick coal seams according to claim 2, characterized in that, The modification measures carried out in low-energy areas and microseismic accumulation paths are shallow blasting.

4. The method for modifying the overburden of steeply dipping, extra-thick coal seams according to claim 3, characterized in that, Shallow blasting involves drilling holes and loading explosives on the lower left and lower right sides of the coal seam, with three shallow holes drilled on each side and an angle difference of 15 degrees or more between any two shallow holes.

5. The method for modifying the overburden of steeply dipping, extra-thick coal seams according to claim 3, characterized in that, The length of the shallow hole is half that of the deep hole.

6. The method for modifying overburden in steeply dipping, extra-thick coal seams according to claim 1, characterized in that, The two deep holes are at angles of 25 degrees and 35 degrees to the horizontal plane, respectively. The three shallow holes are at angles of 25 degrees, 45 degrees and 60 degrees to the horizontal plane, respectively.

7. The method for modifying the overburden of steeply dipping, extra-thick coal seams according to any one of claims 1-6, characterized in that, Before the blasting, water was injected into the middle of the rock pillar between the two tunnels.

8. The method for modifying overburden in steeply dipping, extra-thick coal seams according to claim 7, characterized in that, The length of the water injection hole is 135m and the angle is 6 degrees.

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