CN115419407B - Pressure relief protection method for roadway affected by mining - Google Patents
Pressure relief protection method for roadway affected by mining Download PDFInfo
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- CN115419407B CN115419407B CN202211286266.8A CN202211286266A CN115419407B CN 115419407 B CN115419407 B CN 115419407B CN 202211286266 A CN202211286266 A CN 202211286266A CN 115419407 B CN115419407 B CN 115419407B
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- E—FIXED CONSTRUCTIONS
- E21—EARTH DRILLING; MINING
- E21C—MINING OR QUARRYING
- E21C37/00—Other methods or devices for dislodging with or without loading
- E21C37/06—Other methods or devices for dislodging with or without loading by making use of hydraulic or pneumatic pressure in a borehole
- E21C37/12—Other methods or devices for dislodging with or without loading by making use of hydraulic or pneumatic pressure in a borehole by injecting into the borehole a liquid, either initially at high pressure or subsequently subjected to high pressure, e.g. by pulses, by explosive cartridges acting on the liquid
Abstract
The application discloses a pressure relief protection method of a roadway affected by mining, which comprises the following steps: determining the type of a protected roadway and the mining stress propagation path; determining a control method based on the roadway type and the mining stress propagation path; determining parameters of weak coal-rock structures based on the control method; determining hydraulic fracturing parameters based on the coal rock weak structure parameters; based on the hydraulic fracturing parameters, hydraulic fracturing is carried out to form a weak coal-rock structure; and evaluating the transfer effect of the mining stress. By artificially increasing cracks in the coal rock mass, active coal rock mass structural transformation is implemented to form a weak structure body, the bearing characteristics of the coal rock mass are weakened, and a pressure relief protection area is established so as to realize stress transfer and pressure relief control, thereby achieving the purpose of protecting a roadway. The method solves the problem that different types of mining-affected roadways are difficult to control, and has great popularization and application prospects.
Description
Technical Field
The application belongs to the technical field of coal mine safety, and particularly relates to a pressure relief protection method for a roadway affected by mining.
Background
In China, coal mine mainly adopts underground mining, so that the tunneling engineering quantity of underground tunnel is huge, and the new tunneling tunnel length of each year of coal mine can reach about 12000 km. The stability of the roadway is guaranteed, and the requirement of safe and efficient production of the coal mine is met. In the coal mine production process, about 70% of roadways are affected by mining stress, and the development of the coal mine is severely restricted by the problem that the roadway deformation is difficult to control due to mining. In order to ensure normal production of coal mines, certain measures must be taken to protect the tunnel affected by mining, and undoubtedly, the stress environment around the tunnel is improved, so that the requirement of safe mining is met, and the method is an important way for safe and efficient mining of coal. The most direct and effective way to achieve the improvement of the stress environment around the roadway is to cut off the stress propagation path between the stress source and the roadway. The mining stress is mainly the stress which dynamically changes along with the mining activity, and the mining stress can be transmitted along the path of the stress source, the load-carrying stratum and the load-carrying coal stratum, so that the transmission path of the mining stress is controlled, the carrying capacity of the load-carrying body is changed, the transmission mode and the distribution characteristic of the load-carrying body are changed, and the improvement of the high-stress environment around the tunnel affected by the mining can be realized. The key scientific problem related to the improvement of the high-stress environment is that the coal-rock mass structure is reformed, namely, the cracks are artificially added in the coal-rock mass, the active coal-rock mass structure is reformed, the bearing property of the coal-rock mass is weakened, and the stress transfer and the pressure relief control are realized.
The traditional pressure relief modes in China comprise pressure relief roadways, pressure relief grooves, large-diameter drilling holes, deep hole blasting and the like, and the pressure relief modes have certain pressure relief effects, but all involve the problems of large engineering quantity, non-ideal pressure relief effect and the like of field implementation, and the effectiveness of pressure relief is greatly limited along with the increasing complexity of mining conditions and stress environments.
Disclosure of Invention
The application provides a pressure relief protection method for a roadway affected by mining, and the purpose of protecting the roadway is achieved by establishing a pressure relief protection area to realize stress transfer and pressure relief control.
To achieve the above object, the present application provides the following solutions:
a pressure relief protection method of a roadway affected by mining comprises the following steps:
determining the type of a protected roadway and the mining stress propagation path;
determining a control method based on the roadway type and the mining stress propagation path;
determining parameters of weak coal-rock structures based on the control method;
determining hydraulic fracturing parameters based on the coal rock weak structure parameters;
based on the hydraulic fracturing parameters, hydraulic fracturing is carried out to form a weak coal-rock structure;
and evaluating the transfer effect of the mining stress.
Preferably, the protected roadway type includes: the coal seam roadway, the bottom plate roadway and the top plate roadway specifically comprise a stope, a mining area up-down mountain, a pre-digging retracting channel, a mining area centralized roadway, a large roadway, a gas drainage roadway and the like.
Preferably, the control method includes: and the transfer of mining stress is realized by forming a weak coal-rock structure body through hydraulic fracturing.
Preferably, the weak structure parameters of coal rock include: horizon, extent, and degree of weakness;
the method for determining the parameters of the weak coal rock structure comprises the following steps:
establishing a numerical calculation model, weakening the stratum layer to obtain a weakened stratum;
obtaining a weakened rock stratum range based on the weakened rock stratum;
and obtaining the weakening degree based on the weakening stratum range.
Preferably, the method of determining the hydraulic fracturing parameters comprises:
calculating the crack expansion radius;
obtaining a drilling interval based on the crack expansion radius;
obtaining the number of the drilled holes based on the drilling intervals and the fracturing roadway length;
and obtaining the number of fracturing sections of the drilled hole based on the number of the drilled holes and the damage variable.
Preferably, the method for calculating the crack propagation radius comprises the following steps:
wherein Q represents initial fracturing displacement, T represents fracturing time, E represents elastic modulus, sigma represents water pressure, H represents seam height, and a represents crack expansion radius.
Preferably, the method for obtaining the drill hole spacing comprises the following steps:
d＝2ka
wherein a represents a crack propagation radius, k represents a crack superposition coefficient, and d represents a drilling pitch.
Preferably, the method for obtaining the number of drill holes comprises the following steps:
m＝l/d
wherein m represents the number of drilling holes, l represents the length of the fracturing roadway, and d represents the drilling hole spacing.
Preferably, the method for obtaining the number of fracturing segments of the borehole comprises the following steps:
wherein n represents the total number of cracks, V represents the fracturing volume, B represents the crack depth, V represents the poisson ratio, f represents the inter-joint interaction coefficient, a represents the crack expansion radius, α represents the inclination angle of the joint surface, and phi represents the friction angle of the joint surface.
Preferably, the method for forming the weak coal-rock structure comprises the following steps: and (3) drilling holes in the tunnel towards the roof, the coal seam or the floor, and carrying out hydraulic fracturing on the determined area to form the coal-rock weak structure.
The beneficial effects of this application are:
the application discloses a pressure relief protection method of a roadway affected by mining, which establishes a pressure relief protection area to realize stress transfer and pressure relief control, thereby achieving the purpose of protecting the roadway. By artificially increasing cracks in the coal rock mass, active coal rock mass structural transformation is implemented, so that a weak coal rock structure is formed, and the purpose of weakening the bearing characteristics of the coal rock stratum is achieved. Aiming at the problem that different types of mining-affected roadways are difficult to control, the invention provides a common solution, and has great popularization and application prospects.
Drawings
For a clearer description of the technical solutions of the present application, the drawings that are required to be used in the embodiments are briefly described below, it being evident that the drawings in the following description are only some embodiments of the present application, and that other drawings can be obtained according to these drawings without inventive effort for a person skilled in the art.
Fig. 1 is a schematic flow chart of a pressure relief protection method for a mining-affected roadway according to an embodiment of the present application;
fig. 2 is a schematic block diagram of a method for protecting a roadway under mining influence according to an embodiment of the present application.
Detailed Description
The following description of the embodiments of the present application will be made clearly and fully with reference to the accompanying drawings, in which it is evident that the embodiments described are only some, but not all, of the embodiments of the present application. All other embodiments, which can be made by one of ordinary skill in the art without undue burden from the present disclosure, are within the scope of the present disclosure.
In order that the above-recited objects, features and advantages of the present application will become more readily apparent, a more particular description of the invention briefly described above will be rendered by reference to specific embodiments that are illustrated in the appended drawings.
Fig. 1 is a schematic flow chart of a method for protecting a roadway under mining influence according to an embodiment of the present application, including the following steps:
determining the type of a protected roadway and the mining stress propagation path;
according to the relative position relation between the mining-affected roadway and the stope, the types of the mining-affected roadway mainly comprise a coal seam roadway, a bottom plate roadway and a top plate roadway, and particularly comprise a stope, a stope up-down mountain, a pre-digging retracting channel, a stope centralized roadway, a main roadway, a gas drainage roadway and the like.
The propagation path includes: stress source, load-carrying rock stratum and loaded coal rock
Determining a control method based on the type of the protected roadway and the mining stress propagation path; and the transfer of mining stress is realized by forming a weak coal-rock structure body through hydraulic fracturing.
Determining parameters of weak structures of coal and rock based on a control method; the weak structure parameters of the coal rock include: horizon, extent, and degree of weakness; the method for specifically determining the parameters of the weak structure body of the coal rock comprises the following steps:
1) Establishing a numerical calculation model, weakening the rock stratum, and obtaining a weakened rock stratum;
adopting UDEC numerical simulation software to establish a numerical calculation model M, sequentially weakening mechanical parameters of different rock layers, analyzing surrounding rock deformation and stress distribution rules of a roadway after weakening the different rock layers, and carrying out optimal analysis on the result to finally obtain a reasonable weakened rock layer;
2) Obtaining a weakened rock stratum range based on the weakened rock stratum;
on the basis of a numerical model M, weakening the target rock stratum in different ranges, analyzing the influence of the weakening ranges on the deformation and stress distribution rule of the surrounding rock, and carrying out optimal analysis on the result to finally obtain a reasonable weakening range;
3) Obtaining a weakening degree based on the weakening stratum range;
the weakening degree of the weak structure body of the coal rock can be represented by a damage variable D, the rock layers in the determined range are weakened to different degrees, the influence of the weakening degree on the deformation of the surrounding rock and the stress distribution rule is analyzed, and finally the reasonable weakening degree, namely the damage variable D, is determined.
Determining hydraulic fracturing parameters based on the weak structure parameters of the coal and rock;
the method for calculating the crack propagation radius comprises the following steps:
wherein Q represents initial fracturing displacement, T represents fracturing time, E represents elastic modulus, sigma represents water pressure, H represents seam height, and a represents crack expansion radius.
The method for obtaining the drilling interval based on the crack propagation radius comprises the following steps:
d＝2ka
where a represents the crack propagation radius, k represents the crack stacking coefficient, and d represents the borehole spacing.
Obtaining the number of drilling holes based on the drilling hole spacing and the fracturing roadway length; the formula for calculating the number of holes is as follows:
m＝l/d
the drilling distance is d, the length of the fracturing roadway is l, and the number of the drilling holes is m.
Based on the number of drill holes and the damage variable, the method for obtaining the number of fracturing sections of the drill holes comprises the following steps:
wherein n represents the total number of cracks, V represents the fracturing volume, B represents the crack depth, V represents the Poisson's ratio, f represents the inter-joint interaction coefficient, a represents the crack expansion radius, alpha represents the inclination angle of the joint surface,
the friction angle of the joint surface is shown.
Based on hydraulic fracturing parameters, carrying out hydraulic fracturing to form a weak coal-rock structure; and (3) drilling holes are constructed in the roof, the coal seam or the bottom plate in the protected roadway, and hydraulic fracturing is carried out on the determined area to form the coal-rock weak structure.
Evaluating the transfer effect of the mining stress; by on-site monitoring, the stress and deformation rule of the surrounding rock of the roadway before and after fracturing are changed, and then the stress transfer effect is evaluated, as shown in fig. 2.
The foregoing embodiments are merely illustrative of the preferred embodiments of the present application and are not intended to limit the scope of the present application, and various modifications and improvements made by those skilled in the art to the technical solutions of the present application should fall within the protection scope defined by the claims of the present application.
Claims (8)
1. The pressure relief protection method for the mining-affected roadway is characterized by comprising the following steps of:
determining the type of a protected roadway and the mining stress propagation path;
determining a control method based on the roadway type and the mining stress propagation path;
determining parameters of weak coal-rock structures based on the control method;
determining hydraulic fracturing parameters based on the coal rock weak structure parameters;
based on the hydraulic fracturing parameters, hydraulic fracturing is carried out to form a weak coal-rock structure;
evaluating the transfer effect of the mining stress;
the method of determining the hydraulic fracturing parameters includes:
calculating the crack expansion radius;
obtaining a drilling interval based on the crack expansion radius;
obtaining the number of the drilled holes based on the drilling intervals and the fracturing roadway length;
obtaining the number of fracturing sections of the drilled hole based on the number of the drilled holes and the damage variable;
the method for obtaining the number of the fracturing sections of the drilled hole comprises the following steps:
wherein n represents the number of fracturing segments of a drilled hole, V represents the fracturing volume, B represents the fracture depth, V represents the poisson ratio, f represents the inter-joint interaction coefficient, a represents the fracture expansion radius, alpha represents the inclination angle of the joint surface, phi represents the friction angle of the joint surface, m represents the number of drilled holes, and D represents the damage variable.
2. The mining-affected roadway pressure relief protection method of claim 1, wherein the protected roadway type comprises: the coal seam roadway, the bottom plate roadway and the top plate roadway specifically comprise a stope, a mining area ascending and descending mountain, a pre-digging retracting channel, a mining area centralized roadway, a large roadway and a gas drainage roadway.
3. The mining-affected roadway pressure relief protection method of claim 1, wherein the control method comprises: and the transfer of mining stress is realized by forming a weak coal-rock structure body through hydraulic fracturing.
4. The method for protecting a mining-affected roadway according to claim 1, wherein the coal rock weak structure parameters include: horizon, extent, and degree of weakness;
the method for determining the parameters of the weak coal rock structure comprises the following steps:
establishing a numerical calculation model, weakening the stratum layer to obtain a weakened stratum;
obtaining a weakened rock stratum range based on the weakened rock stratum;
and obtaining the weakening degree based on the weakening stratum range.
5. The method of pressure relief protection of a mining-affected roadway of claim 1, wherein the method of calculating the fracture propagation radius comprises:
wherein Q represents initial fracturing displacement, T represents fracturing time, E represents elastic modulus, sigma represents water pressure, H represents seam height, and a represents crack expansion radius.
6. The method for pressure relief protection of a mining-affected roadway of claim 1, wherein the method for obtaining the borehole spacing comprises:
d＝2ka
wherein a represents a crack propagation radius, k represents a crack superposition coefficient, and d represents a drilling pitch.
7. The method for pressure relief protection of a mining-affected roadway of claim 1, wherein the method for deriving the number of boreholes comprises:
m＝l/d
wherein m represents the number of drilling holes, l represents the length of the fracturing roadway, and d represents the drilling hole spacing.
8. The method for protecting a mining-affected roadway from pressure relief of claim 1, wherein the method for forming the weak coal-rock structure comprises: and (3) drilling holes in the tunnel towards the roof, the coal seam or the floor, and carrying out hydraulic fracturing on the determined area to form the coal-rock weak structure.
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| CN202211286266.8A CN115419407B (en) | 2022-10-20 | 2022-10-20 | Pressure relief protection method for roadway affected by mining |
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| CN202211286266.8A CN115419407B (en) | 2022-10-20 | 2022-10-20 | Pressure relief protection method for roadway affected by mining |
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| PL400952A1 (en) * | 2009-12-09 | 2013-05-27 | Schlumberger Technology B.V. | Method for enlarging the area of fracturing |
| WO2016198894A2 (en) * | 2015-06-10 | 2016-12-15 | Ikon Science Innovation Limited | Method and apparatus for reservoir analysis and fracture design in a rock layer |
| CN106321049B (en) * | 2016-09-27 | 2019-04-23 | 天地科技股份有限公司 | Utilize the method and device of hydraulic fracturing release optimization the position of terminal mining line |
| CN107083961B (en) * | 2017-05-10 | 2019-04-26 | 中国矿业大学 | Laneway stress transfer method is pressed by force based on pressure break circle |
| CN107152279A (en) * | 2017-06-06 | 2017-09-12 | 天地科技股份有限公司 | Wangeviry stope top plate hydraulic fracturing method for weakening and device |
| CN110685689B (en) * | 2019-10-30 | 2020-11-27 | 中国矿业大学 | Large-deformation roadway pressure relief method under influence of mining stress |
| CN111322076A (en) * | 2020-03-03 | 2020-06-23 | 中国矿业大学 | Method for forming roadway scour-prevention weak structure through coal rock hydraulic fracturing |
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