CN110080771B - Method for preventing rock burst by modifying energy release of deep-well high-stress main roadway coal pillar - Google Patents
Method for preventing rock burst by modifying energy release of deep-well high-stress main roadway coal pillar Download PDFInfo
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- CN110080771B CN110080771B CN201910425018.9A CN201910425018A CN110080771B CN 110080771 B CN110080771 B CN 110080771B CN 201910425018 A CN201910425018 A CN 201910425018A CN 110080771 B CN110080771 B CN 110080771B
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- E—FIXED CONSTRUCTIONS
- E21—EARTH DRILLING; MINING
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- E21C41/16—Methods of underground mining; Layouts therefor
- E21C41/18—Methods of underground mining; Layouts therefor for brown or hard coal
Abstract
The invention provides a method for preventing rock burst by modifying energy release of a deep-well high-stress large roadway coal pillar, belonging to the technical field of mining. The method comprises the steps of firstly, carrying out large-diameter pressure relief drilling to release the accumulated elastic energy of the coal body; secondly, carrying out ultrahigh-pressure fixed-point hydraulic fracturing in the large-diameter drill hole to crack the complete coal pillar and weaken the energy storage capacity of the large roadway coal pillar; then, grouting reinforcement is carried out on the fractured coal pillars in the main roadway, the strength of the coal pillars in the main roadway is increased, and the impact threshold is improved; and finally, implementing reinforcing support to increase the impact resistance of the large roadway coal pillar. According to the method, the accumulated elastic energy of the main roadway coal pillars is released, the physical and mechanical properties of the main roadway coal pillars are changed, the impact threshold of the main roadway coal pillars is improved, the elastic energy accumulated by the high-stress main roadway coal pillars can be effectively reduced, and the problem that the surrounding rock is easy to deform greatly due to the reduction of the strength after the pressure of the main roadway coal pillars is relieved is solved.
Description
Technical Field
The invention relates to the technical field of mining, in particular to a method for preventing rock burst by modifying energy release of deep-well high-stress main roadway coal pillars.
Background
With the continuous increase of the coal mining depth and strength in China, the areas, mines and impact times where rock burst disasters occur are increased rapidly, so that the damage to the safety and production of coal mines is increasingly prominent, and the coal mine is one of the key problems in coal mine production in partial areas in China. Especially for the large lanes on the upper mountain and the lower mountain, the service life is long, the throughput is large, and the method is particularly important for protecting the coal pillars of the large lanes.
The purpose of the main roadway coal pillars is to ensure the normal use of a plurality of main roadways, and the existing method for preventing and controlling rock burst of the main roadway coal pillars generally adopts two modes of pressure relief and reinforcement. The large deformation is easily caused by the pressure relief of the large roadway coal pillar, and the normal use of the roadway is influenced; the reinforced main roadway coal pillars are easy to accumulate a larger amount of elastic energy, and when the load exceeds the supporting capacity, serious disasters are easily induced. Chinese patent CN108757881A discloses a rock burst prevention and control method for a three-dimensional coal pillar coal-pressing area, which utilizes a drilling blasting technology to gradually dissipate high-energy level energy accumulated inside a coal wall to form a plurality of pressure relief block areas so as to eliminate the risk of impact. The adopted method does not reinforce the pressure relief coal body, and the service life of the roadway is easily affected by large deformation of the coal body and surrounding rocks. Chinese patent CN208473911U provides a yielding large-deformation split anchor cable for reinforcing coal pillars. The stability of the coal pillar under the condition of impact large deformation (2000mm) and the double functions of yielding large deformation and bidirectionally reinforcing the coal pillar for the anchor cable are realized. The method has complex construction on the whole large roadway coal pillar, the requirement on anchor cable materials is high, and the coal pillar is easy to accumulate a large amount of elastic energy.
The invention provides a method for carrying out large-diameter pressure-relief drilling and forced powder discharge treatment on a large roadway coal pillar, then carrying out ultrahigh-pressure fixed-point hydraulic fracturing on the coal body, filling fracturing cracks with cement mortar, and carrying out reinforcing and supporting, so that the elastic energy accumulated by the high-stress large roadway coal pillar is effectively reduced, and the problem that the surrounding rock is easy to deform greatly due to strength reduction after the large roadway coal pillar is subjected to pressure relief is solved.
Disclosure of Invention
The invention aims to solve the technical problem of providing a method for preventing rock burst by modifying energy release of a deep well high-stress main roadway coal pillar.
The method comprises the following steps:
s1: large-diameter pressure relief drilling is carried out, and the elastic energy accumulated by the coal body is released;
s2: carrying out ultrahigh-pressure fixed-point hydraulic fracturing in the large-diameter drill hole to crack the complete coal pillar and weaken the energy storage capacity of the large roadway coal pillar;
s3: grouting reinforcement is carried out on the fractured coal pillar of the main roadway, the strength of the coal pillar of the main roadway is increased, and the impact threshold is improved;
s4: and (5) implementing reinforcement support and increasing the impact resistance of the large roadway coal pillar.
Wherein, implementing the large-diameter pressure relief drilling in S1 specifically comprises: and (3) carrying out large-diameter pressure relief drilling on the large-roadway coal pillars in the roadway, wherein the distance between the drilled hole and the bottom plate is 0.5-1.2 m.
The S2 specifically comprises the following steps: and after the hole packer is expanded and the pressure reaches the working pressure, injecting high-pressure water into the first fracturing section to fracture the coal body, wherein the water injection pressure is more than 25 Mpa.
After the coal body fracturing operation of the first fracturing section is completed, the hole packer is moved backwards by 5-10 m in the same drilling hole, the fracturing operation of the second fracturing section is started, and the operation is repeated in a circulating mode until the fracturing of all the fracturing sections of the drilling hole is completed. All the fracturing sections such as the first fracturing section and the second fracturing section are arranged outwards from the deepest part of the drilled hole.
After fracturing of all the fracturing sections of the drill hole is completed, the fracturing equipment is moved to the next drill hole until fracturing work of all the main roadway coal pillars is completed.
S3 specifically includes: during grouting reinforcement, a large-diameter pressure relief drill hole is adopted in a grouting drill hole, grout is injected into the main roadway coal pillar through a grouting pipeline, a grouting hole packer is used for sealing the hole, and the next stage is moved after filling of the filling section is completed.
And S4, supporting comprises anchor rods, anchor cables and anchor net supporting.
The technical scheme of the invention has the following beneficial effects:
the method releases the elastic energy accumulated by the coal body, weakens the energy storage capacity of the large roadway coal pillar, increases the strength of the large roadway coal pillar, improves the impact threshold, increases the impact resistance of the large roadway coal pillar, effectively reduces the elastic energy accumulated by the high-stress large roadway coal pillar, and solves the problem that the surrounding rock is easy to deform greatly due to the reduction of the strength after the pressure of the large roadway coal pillar is relieved.
Drawings
FIG. 1 is a schematic diagram of large-diameter drilling pressure relief by the method for preventing rock burst through energy release modification of deep-well high-stress large roadway coal pillars;
FIG. 2 is a schematic illustration of a retreating fixed point hydraulic fracturing of the present invention;
FIG. 3 is a schematic diagram of a retreating type ultrahigh pressure hydraulic fracturing main roadway coal pillar according to the invention;
fig. 4 is a schematic diagram of a coal pillar of a fractured main roadway formed by grouting according to the invention.
Wherein: 1-a top plate; 2-a bottom plate; 3-main lane coal pillar; 4, laneway; 5, drilling a large-diameter pressure relief hole; 6-pressure relief front support pressure curve; 7-pressure bearing curve after pressure relief; 8-fracturing the hole; 9-hole packer; 10-water supply pipe of hole packer; 11-fracturing section water supply pipe; 12 — a first fracturing stage; 13-a second fracture stage; 14-fracturing pipeline stop valve; 15-water supply pump station; 16-a water supply pipe; 17-an unloading valve; 18-hole sealing pipeline; 19-fracturing the pipeline; 20-a pressure sensor; 21-a flow meter; 22-sealing hole pipeline stop valve; 23-a pressure gauge; 24-fracturing effect; 25-grouting effect; 26-grouting pipeline; 27-grouting hole packer; 28-grouting process; 29-ultrahigh pressure hydraulic fracturing process; 30-grouting pump; 31-grouting pressure gauge.
Detailed Description
In order to make the technical problems, technical solutions and advantages of the present invention more apparent, the following detailed description is given with reference to the accompanying drawings and specific embodiments.
The invention provides a method for preventing rock burst by modifying energy release of a deep-well high-stress large roadway coal pillar.
The method comprises the following steps:
s1: large-diameter pressure relief drilling is carried out, and the elastic energy accumulated by the coal body is released;
s2: carrying out ultrahigh-pressure fixed-point hydraulic fracturing in the large-diameter drill hole to crack the complete coal pillar and weaken the energy storage capacity of the large roadway coal pillar;
s3: grouting reinforcement is carried out on the fractured coal pillar of the main roadway, the strength of the coal pillar of the main roadway is increased, and the impact threshold is improved;
s4: and (5) implementing reinforcement support and increasing the impact resistance of the large roadway coal pillar.
The following description is given with reference to specific examples.
In the specific implementation process, as shown in fig. 1, the main roadway coal pillars 3 are located between the top plate 1 and the bottom plate 2, large-diameter pressure relief drill holes 5 are implemented in the roadway 4 for the main roadway coal pillars 3 to relieve pressure, the hole diameter is 110mm, the drill hole depth is 20m, the distance between dangerous areas is 15-30 m, the distance between the drill holes and the bottom plate is generally 0.5-1.2 m, and the pressure bearing curve 6 before pressure relief is reduced to the pressure bearing curve 7 after pressure relief.
And further, carrying out large-diameter drilling pressure relief on the whole large roadway coal pillar.
Further, as shown in fig. 3, in order to fully utilize the existing underground roadway and drilling system, the fracturing drill hole adopts a large-diameter pressure relief drill hole, and the system is composed of a fracturing pipeline stop valve 14, a water injection pump station 15, a water supply pipe 16, an unloading valve 17, a hole sealing pipeline 18, a fracturing pipeline 19, a pressure sensor 20, a flowmeter 21, a hole sealing pipeline stop valve 22, a pressure gauge 23, a hole sealer 9, and the like, and the working process is as follows: opening a water supply pipe 16, starting a pump station 15, injecting high-pressure water into the hole sealing device 9 through a hole sealing pipeline 18, and closing a hole sealing pipeline stop valve 22 after the hole sealing device 9 expands and the pressure reaches the working pressure to complete hole sealing; opening a fracturing pipeline stop valve 14, injecting high-pressure water into the first fracturing section 12 of the coal body, and closing an unloading valve 17 after the coal pillar of the main roadway is fractured; and opening the stop valve 22 of the hole sealing pipeline 18, releasing the internal pressure of the hole sealing device 9, and shutting down the water supply pump station 15.
And further, performing ultrahigh-pressure hydraulic fracturing on the pressure-relieved main roadway coal pillar to crack the complete coal body, wherein the water injection pressure is more than 25 MPa.
And further, moving the hole packer backwards for 5-10 m in the same drilling hole, starting fracturing operation of the second fracturing section 13, and circulating until fracturing of all fracturing sections of the drilling hole is completed.
And further, moving the fracturing equipment to the next drill hole until the fracturing work of all the main roadway coal pillars is completed. The fracturing effect 24 is shown in fig. 3.
Specifically, the drilling comprises the following specific steps:
as shown in fig. 2, water is injected into the hole packer 9 through a hole packer water supply pipe 10, water is supplied to a fracturing section water supply pipe 11 after the pressure reaches a certain value, the fracturing work is performed on the first fracturing section 12 roadway coal pillars, water supply to the fracturing section water supply pipe 11 is stopped after the coal body of the first fracturing section 12 is sufficiently fractured, water supply to the hole packer water supply pipe 10 is stopped after the water supply pressure is reduced, the fracturing equipment is integrally moved backward by 5-10 m to a second fracturing section 13 after the pressure of the hole packer 9 is reduced to a certain value, the fracturing work is repeated until the coal body in the range of the fracturing drill hole 8 is sufficiently cracked, the fracturing equipment is integrally moved to the next fracturing drill hole, and the operation is circularly repeated until all the fracturing work of the roadway coal pillars 3 is completed.
Grouting the fractured main roadway coal pillars by a grouting process 28, and in order to fully utilize the existing underground roadway and a drilling system, large-diameter pressure relief drilling is adopted for grouting drilling, as shown in fig. 4. And (3) grouting the slurry into the main roadway coal pillar 3 through a grouting pipeline 26, sealing holes by using a grouting hole sealing device 27, and moving to the next stage after the filling of the filling section is finished.
And further, circularly reciprocating until the grouting work of the whole main roadway coal pillar is completed. The grouting effect 25 is shown in fig. 4.
The concrete steps of the grouting drilling are as follows:
and injecting water into the grouting hole packer 27 for pressurization to plug the grouting hole. Grouting the grouting holes through the grouting pump 30 and the grouting pipeline 26, wherein the grouting pressure is 2Mpa, and when a grouting phenomenon occurs or the grouting pressure gauge 31 is 1.0-1.5 Mpa and is stable for more than ten minutes, the grouting of the section is completed. And (3) releasing the pressure of the grouting hole packer 27, moving the whole grouting equipment to the next grouting drill hole, and circularly reciprocating until the grouting of the whole main roadway coal pillar is finished.
And (4) carrying out reinforcing support on the grouted and reinforced main roadway coal pillar in various support modes (optional) such as anchor rods (cables), anchor nets and the like.
While the foregoing is directed to the preferred embodiment of the present invention, it will be understood by those skilled in the art that various changes and modifications may be made without departing from the spirit and scope of the invention as defined in the appended claims.
Claims (3)
1. A method for preventing rock burst by modifying energy release of deep-well high-stress main roadway coal pillars is characterized by comprising the following steps: the method comprises the following steps:
s1: large-diameter pressure relief drilling is carried out, and the elastic energy accumulated by the coal body is released;
s2: carrying out ultrahigh-pressure fixed-point hydraulic fracturing in the large-diameter drill hole to crack the complete coal pillar and weaken the energy storage capacity of the large roadway coal pillar;
s3: grouting reinforcement is carried out on the fractured coal pillar of the main roadway, the strength of the coal pillar of the main roadway is increased, and the impact threshold is improved;
s4: reinforcing and supporting are implemented, and the impact resistance of the large roadway coal pillar is improved;
the implementation of the large-diameter pressure relief drilling in the S1 is specifically as follows: performing large-diameter pressure relief drilling on the large roadway coal pillar in the roadway, wherein the distance between the drilled hole and the bottom plate is 0.5-1.2 m;
the step S2 specifically includes: after the hole packer is expanded and the pressure reaches the working pressure, injecting high-pressure water into the first fracturing section to fracture the coal body, wherein the water injection pressure is more than 25 Mpa;
after the coal body fracturing operation of the first fracturing section is completed, moving a hole packer backwards for 5-10 m in the same drilling hole, starting fracturing operation of a second fracturing section, and circulating until fracturing of all fracturing sections of the drilling hole is completed;
after fracturing of all fracturing sections of the drill hole is completed, moving the fracturing equipment to the next drill hole until fracturing work of all the large roadway coal pillars is completed;
the S3 specifically includes: during grouting reinforcement, a large-diameter pressure relief drill hole is adopted in a grouting drill hole, grout is injected into the main roadway coal pillar through a grouting pipeline, a grouting hole packer is used for sealing the hole, and the next stage is moved after filling of the filling section is completed.
2. The method for preventing rock burst by modifying energy release of deep-well high-stress main roadway coal pillars according to claim 1, characterized by comprising the following steps: and the support in the S4 comprises anchor rods, anchor cables and anchor net supports.
3. The method for preventing rock burst by modifying energy release of deep-well high-stress main roadway coal pillars according to claim 1, characterized by comprising the following steps: the first fracturing section and the second fracturing section are arranged outwards from the deepest part of the drill hole.
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| CN111927456B (en) * | 2020-09-10 | 2022-04-19 | 山东科技大学 | Dynamic-loading deep mining area coal pillar instability unloading-fixing-letting multistage prevention and control method |
| CN112987094B (en) * | 2021-02-20 | 2022-01-11 | 北京科技大学 | Hydraulic fracturing influence range evaluation method based on coal seam wave velocity field test |
| CN113236250B (en) * | 2021-05-11 | 2024-04-05 | 中煤科工开采研究院有限公司 | Impact-prevention method for rock burst coal seam |
| CN113266356A (en) * | 2021-06-17 | 2021-08-17 | 天地科技股份有限公司 | Hydraulic weakening method for upper coal pillar supporting pressure in short-distance coal seam mining |
| CN114293989B (en) * | 2021-11-23 | 2022-09-02 | 北京科技大学 | Anti-scour method for near-vertical ultra-thick coal seam subsection hydraulic fracturing area |
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| DE2850297A1 (en) * | 1978-11-20 | 1980-06-04 | Ruhrkohle Ag | Rock burst monitor for mine - has pressure gauge on liq. filled plastic hose inserted in advance borehole |
| CN101936162B (en) * | 2010-04-16 | 2012-04-18 | 兖州煤业股份有限公司 | Method for preventing rock burst of bottom plate of layered tunnel in tectonic stress region of coal mine |
| CN101915098A (en) * | 2010-07-14 | 2010-12-15 | 中国矿业大学 | Method for preventing and controlling rock burst through hydraulic cutting |
| CN102296958A (en) * | 2011-07-22 | 2011-12-28 | 山东科技大学 | Method for preventing rock burst by artificial space defect body |
| CN102322262A (en) * | 2011-09-12 | 2012-01-18 | 山东科技大学 | Colliery isolated island coal column crossheading bump control method |
| CN107304676A (en) * | 2016-04-22 | 2017-10-31 | 黑龙江龙煤鹤岗矿业有限责任公司 | A kind of prevention and controls for leaving bump under coal column |
| CN108386192A (en) * | 2018-01-31 | 2018-08-10 | 中国矿业大学 | A kind of method of active Enhanced support and active release prevention bump |
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