A coal mine roadway floor heave prevention and treatment method based on floor blasting pressure relief

Abstract

The application provides a coal mine roadway floor heave prevention and treatment method based on floor blasting pressure relief, which comprises the following steps: determining the interval C of different section blasting boreholes according to the roadway floor surrounding rock properties and explosive characteristics; constructing the blasting boreholes in the roadway floor according to the interval C of different section blasting boreholes, wherein the blasting borehole construction at least comprises two inner side wall blasting boreholes perpendicular to the roadway trend, and one floor blasting borehole parallel to the working face advancing direction; loading the blasting cartridge and the binding material into the blasting borehole, wherein the blasting cartridge and the binding material are arranged along the axial direction of the borehole at intervals, and the borehole is sealed by using the sealing material; detonating the blasting cartridge, and simultaneously achieving the pressure relief of the floor rock mass and the reinforcement of the broken rock mass by the binding material through the energy generated by the blasting.

Description

Technical Field

[0001] This invention relates to the field of coal mine disaster management technology, and in particular to a method for preventing floor heave in coal mine roadways based on floor blasting pressure relief. Background Technology

[0002] Currently, coal mine roadways, especially tunneling faces, often experience significant floor heave after excavation. This floor heave poses a considerable threat to mine safety and the safety of personnel and equipment. Existing prevention and control methods are mostly passive, involving manual floor removal after the heave has occurred. This method is time-consuming, labor-intensive, inefficient, and requires repetitive work, failing to provide a complete cure in one go.

[0003] Some methods rely solely on floor pressure relief drilling, floor blasting, or floor trenching for pressure relief. These methods only consider one aspect of pressure relief and can only reduce floor heave deformation and delay it to some extent when the surrounding rock conditions are relatively good. However, as the loose and fractured coal-bearing rock mass is compacted, the pressure relief effect disappears. When the roadway itself is loose and fractured, blasting pressure relief is equivalent to expanding the fracture range of the surrounding rock. As a result, the surrounding rock within the entire fracture range deforms together and is squeezed into the roadway space. This not only fails to reduce the amount of roadway deformation but also increases it.

[0004] In view of this, a method for preventing bottom heave by simultaneously blasting, depressurization, grouting, and reinforcement is provided, which is of great significance for improving mine production safety and ensuring normal mine production. Summary of the Invention

[0005] The present invention aims to at least partially solve one of the technical problems in the related art.

[0006] To achieve the above objectives, this invention proposes a method for preventing floor heave in coal mine roadways based on floor blasting pressure relief, comprising the following steps:

[0007] S1. Determine the spacing C of blasting boreholes with different cross sections based on the properties of the surrounding rock of the tunnel floor and the characteristics of the explosives; S2. Blasting boreholes are constructed on the roadway floor according to the blasting hole spacing C of different cross sections. The blasting borehole construction includes at least two inner wall blasting boreholes perpendicular to the roadway direction and one floor blasting borehole parallel to the working face excavation direction. S3. Explosive cartridges and adhesive materials are loaded into the blasting borehole. The explosive cartridges and adhesive materials are arranged at intervals along the borehole axis, and the borehole is sealed with sealing material. S4. Detonate the explosive charge to simultaneously relieve pressure on the bottom rock mass and reinforce the fractured rock mass with the bonding material using the energy generated by the explosion.

[0008] This invention achieves stress relief and rock mass reinforcement simultaneously through a single blasting operation by adding a bonding material into the blast hole. The blasting energy creates a pressure relief space and instantly drives the bonding material to penetrate and cement newly formed fractures and existing broken rock mass, forming a reinforced load-bearing ring that fundamentally suppresses bottom heave and provides a long-lasting effect.

[0009] Optionally, in step S1, the spacing C of blasting boreholes with different cross-sections is calculated according to the following formula: ; Where C is the borehole spacing, in meters; Drilling radius, in mm; The detonation velocity of the explosive is expressed in m / s. Poisson's ratio of the coal body; Density of the explosive, in kg / m³; Tensile strength of coal, in MPa.

[0010] Furthermore, in S2, the opening of the two inner wall blasting boreholes perpendicular to the roadway direction is 0.2 to 0.5 m from the roadway floor, the borehole inclination angle is -60° to -65°, and the borehole depth is 15 to 20 m.

[0011] Furthermore, in S2, the borehole opening of the bottom plate blasting borehole parallel to the working face excavation direction is located at the center of the roadway bottom plate, the borehole inclination angle is -60° to -65°, and the borehole depth is 15 to 20m.

[0012] Furthermore, the total length of the explosive charge is no greater than 1 / 3 of the drilling depth, the total length of the bonding material is no greater than 1 / 3 of the drilling depth, and the length of the sealing material is no less than 1 / 3 of the drilling depth.

[0013] Furthermore, the bonding material comprises one or more combinations of cement, water glass, or chemical grouting materials.

[0014] Furthermore, in step S3, the explosive charge and the adhesive material are respectively packaged into an integrated explosive charge using plastic packaging.

[0015] Furthermore, in S2, the blasting and breaking range areas of adjacent cross-sections of the blasting boreholes are tangent or have overlapping portions.

[0016] Additional aspects and advantages of the invention will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention. Attached Figure Description

[0017] The above and / or additional aspects and advantages of the present invention will become apparent and readily understood from the following description of the embodiments taken in conjunction with the accompanying drawings, wherein: Figure 1 This is a schematic diagram of the method steps for preventing floor heave in coal mine roadways based on floor blasting pressure relief according to the present invention; Figure 2 This is a schematic diagram of the layout of blasting boreholes in a coal mine roadway according to a method for preventing floor heave based on floor blasting pressure relief according to the present invention. Figure 3 This is a schematic diagram of the layout of blasting boreholes in a coal mine roadway according to another angle, based on a method for preventing floor heave in coal mine roadways according to the present invention. Figure 4 This is a schematic diagram of the layout of blasting boreholes in a coal mine roadway according to another angle, based on a method for preventing floor heave in coal mine roadways according to the present invention. Figure 5 This is a schematic diagram of the layout of explosive charges and bonding materials inside the blasting borehole in a coal mine roadway heave prevention method based on bottom plate blasting pressure relief according to the present invention. Detailed Implementation

[0018] Embodiments of the present invention are described in detail below, examples of which are illustrated in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and intended to explain the present invention, and should not be construed as limiting the present invention.

[0019] This invention proposes a method for preventing floor heave in coal mine roadways based on floor blasting pressure relief, as described below. Figures 1 to 5 Please provide a detailed explanation.

[0020] A method for preventing floor heave in coal mine roadways based on floor blasting pressure relief includes the following steps: S1. Determine the spacing C of blasting boreholes with different cross sections based on the properties of the surrounding rock of the tunnel floor and the characteristics of the explosives; S2. Blasting boreholes are constructed on the roadway floor according to the blasting hole spacing C of different cross sections. The blasting borehole construction includes at least two inner wall blasting boreholes perpendicular to the roadway direction and one floor blasting borehole parallel to the working face excavation direction. S3. Explosive cartridges and adhesive materials are loaded into the blasting borehole. The explosive cartridges and adhesive materials are arranged at intervals along the borehole axis, and the borehole is sealed with sealing material. S4. Detonate the explosive charge to simultaneously relieve pressure on the bottom rock mass and reinforce the fractured rock mass with the bonding material using the energy generated by the explosion.

[0021] This invention integrates grouting functionality into conventional blasting processes by adding a bonding material into the blasting hole. It eliminates the need for complex specialized equipment or multi-stage construction, achieving stress relief and rock mass reinforcement simultaneously in a single blasting operation. The blasting energy creates a pressure relief space and instantly drives the bonding material to penetrate, cementing newly formed fractures and existing broken rock masses, forming a reinforced load-bearing ring that fundamentally suppresses floor heave with long-lasting effects. Furthermore, it changes the reactive, post-explosive treatment model, proactively implementing the treatment after tunnel excavation or before floor heave occurs, avoiding repeated floor-breaking operations and significantly improving production safety and efficiency. It is particularly suitable for loose and broken surrounding rock conditions, solving the technical problem that simple blasting may exacerbate deformation. By reinforcing, it offsets the potential negative impacts of pressure relief, ensuring high safety.

[0022] In some embodiments, in step S1, the spacing C of blasting boreholes with different cross-sections is calculated according to the following formula: ; Where C is the borehole spacing, in meters; Drilling radius, in mm; The detonation velocity of the explosive is expressed in m / s. Poisson's ratio of the coal body; Density of the explosive, in kg / m³; Tensile strength of coal, in MPa.

[0023] It should be noted that the spacing C calculated using this formula aims to ensure that the radial fracture zones generated by adjacent borehole blasts are precisely connected or moderately overlapped, thereby forming a continuous or network-like artificial stress relief zone below the roadway floor, effectively cutting off the transmission path of high stress to the roadway floor. The calculation "based on different cross-sections" reflects adaptation to the non-uniformity of surrounding rock conditions along the roadway's strike, achieving dynamic optimization design and avoiding discontinuous stress relief due to excessively large spacing, or cost waste and excessive damage to the surrounding rock due to excessively small spacing.

[0024] As can be seen from the above, in some embodiments, in S2, the blasting and breaking range areas of adjacent cross-sections of the blasting boreholes are tangent or have overlapping portions.

[0025] In some embodiments, in step S2, the borehole openings of the two inner wall blasting boreholes perpendicular to the roadway direction are 0.2–0.5 m from the roadway floor, with a borehole inclination angle of -60°–-65° and a borehole depth of 15–20 m. This is to specifically weaken the rock mass strength and stress state in the "corner" area below both sides of the roadway, where stress concentration is most severe. This area is a key location for the initiation and development of floor heave.

[0026] In some embodiments, in step S2, the borehole opening of the floor blasting borehole, parallel to the working face excavation direction, is located at the center of the roadway floor, with a borehole inclination angle of -60° to -65° and a borehole depth of 15 to 20 m. The opening is located on the centerline of the roadway floor and is constructed at the same inclination angle and depth. This borehole aims to relieve pressure and reinforce the main load-bearing rock strata directly beneath the roadway.

[0027] It should be noted that the three boreholes are arranged in a triangular pattern in space. The fracture-reinforcement zone formed after their blasting can construct a "reinforced pressure relief arch" with a certain depth, spanning the entire width of the roadway, below the roadway floor. When the blasting ranges of adjacent borehole sections are tangent or overlap, a continuous reinforced pressure relief zone can be formed along the roadway direction, achieving three-dimensional protection of the roadway floor.

[0028] In some embodiments, the total length of the explosive charge is no greater than one-third of the borehole depth, the total length of the bonding material is no greater than one-third of the borehole depth, and the length of the sealing material is no less than one-third of the borehole depth. Specifically, this ratio ensures that the blasting energy is concentrated deep within the borehole, creating sufficient pressure relief space and providing enough kinetic energy for the explosive gas to drive the bonding material. The segmented arrangement of the bonding material ensures effective penetration along the length of the borehole.

[0029] In some embodiments, the bonding material comprises one or more combinations of cement, water glass, or chemical grouting materials.

[0030] In some embodiments, in step S3, the explosive charge and the bonding material are respectively packaged into an integrated explosive charge using plastic bags. Pre-packaging the explosive charge and bonding material into an integrated explosive charge using plastic bags greatly simplifies downhole loading operations, improves construction efficiency and safety, and ensures the accuracy and consistency of the explosive charge structure.

[0031] After the S4 step detonation, the blasting of the fractured rock mass and the injection of bonding material are physicochemical processes that occur almost simultaneously under the same explosive energy, rather than a sequential operation of "blasting first, waiting, and then grouting." This eliminates the time delay and prevents the fractured rock mass from creeping or further deteriorating in an unsupported state.

[0032] Furthermore, the fissures created by the blasting provide penetration channels for the bonding material; the timely injection and solidification of the bonding material, in turn, cements the broken rock blocks, restoring their strength and integrity. Ultimately, a "reinforced bearing layer" with high residual strength and a certain degree of deformation capacity is formed deep within the tunnel floor, composed of cemented broken rock mass.

[0033] Furthermore, this reinforced layer absorbs deformation energy from the deep surrounding rock, acting as a "stress buffer layer." On the other hand, its own strength is sufficient to resist the effects of residual stress, preventing it from being transmitted upwards and causing the roadway floor to bulge. This fundamentally changes the mechanical response mechanism of the floor rock mass, transforming it from an "easily bulging elasto-plastic body" into an "energy-consuming and stable composite structure."

[0034] In the description of this invention, it should be understood that the terms "center," "longitudinal," "lateral," "length," "width," "thickness," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "clockwise," "counterclockwise," "axial," "radial," and "circumferential" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing this invention and simplifying the description, and are not intended to indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this invention.

[0035] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one of that feature. In the description of this invention, "a plurality of" means at least two, such as two, three, etc., unless otherwise explicitly specified.

[0036] In this invention, unless otherwise explicitly specified and limited, the terms "installation," "connection," "linking," and "fixing," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection, an electrical connection, or a connection that allows communication between them; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components, unless otherwise explicitly limited. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0037] In this invention, unless otherwise explicitly specified and limited, "above" or "below" the second feature can mean that the first feature is in direct contact with the second feature, or that the first feature is in indirect contact with the second feature through an intermediate medium. Furthermore, "above," "over," and "on top" of the second feature can mean that the first feature is directly above or diagonally above the second feature, or simply that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature can mean that the first feature is directly below or diagonally below the second feature, or simply that the first feature is at a lower horizontal level than the second feature.

[0038] In this invention, the terms "one embodiment," "some embodiments," "example," "specific example," or "some examples," etc., refer to a specific feature, structure, material, or characteristic described in connection with that embodiment or example, which is included in at least one embodiment or example of the invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples. Moreover, without contradiction, those skilled in the art can combine and integrate the different embodiments or examples described in this specification, as well as the features of different embodiments or examples.

[0039] Although embodiments of the present invention have been shown and described above, it is understood that the above embodiments are exemplary and should not be construed as limiting the present invention. Those skilled in the art can make changes, modifications, substitutions and variations to the above embodiments within the scope of the present invention.

Claims

1. A method for preventing floor heave in coal mine roadways based on floor blasting pressure relief, characterized in that, Includes the following steps: S1. Determine the spacing C of blasting boreholes with different cross sections based on the properties of the surrounding rock of the tunnel floor and the characteristics of the explosives; S2. Blasting boreholes are constructed on the roadway floor according to the blasting hole spacing C of different cross sections. The blasting borehole construction includes at least two inner wall blasting boreholes perpendicular to the roadway direction and one floor blasting borehole parallel to the working face excavation direction. S3. Explosive cartridges and adhesive materials are loaded into the blasting borehole. The explosive cartridges and adhesive materials are arranged at intervals along the borehole axis, and the borehole is sealed with sealing material. S4. Detonate the explosive charge to simultaneously relieve pressure on the bottom rock mass and reinforce the fractured rock mass with the bonding material using the energy generated by the explosion.

2. The method for preventing floor heave in coal mine roadways based on floor blasting pressure relief as described in claim 1, characterized in that, In step S1, the spacing C of the blasting boreholes with different cross-sections is calculated according to the following formula: ； Where C is the borehole spacing, in meters; Drilling radius, in mm; The detonation velocity of the explosive is expressed in m / s. Poisson's ratio of the coal body; Density of the explosive, in kg / m³; Tensile strength of coal, in MPa.

3. The method for preventing floor heave in coal mine roadways based on floor blasting pressure relief as described in claim 1, characterized in that, In S2, the opening of the two inner wall blasting boreholes perpendicular to the roadway direction is 0.2 to 0.5 m from the roadway floor, the borehole inclination angle is -60° to -65°, and the borehole depth is 15 to 20 m.

4. The method for preventing floor heave in coal mine roadways based on floor blasting pressure relief as described in claim 1, characterized in that, In S2, the borehole opening of the bottom plate blasting borehole parallel to the working face excavation direction is located at the center of the roadway bottom plate, the borehole inclination angle is -60° to -65°, and the borehole depth is 15 to 20m.

5. The method for preventing floor heave in coal mine roadways based on floor blasting pressure relief as described in claim 1, characterized in that, In step S3, the total length of the explosive charge is not greater than 1 / 3 of the drilling depth, the total length of the bonding material is not greater than 1 / 3 of the drilling depth, and the length of the sealing material is not less than 1 / 3 of the drilling depth.

6. A method for preventing floor heave in coal mine roadways based on floor blasting pressure relief as described in claim 1 or 5, characterized in that, The bonding material comprises one or more combinations of cement, water glass, or chemical grouting materials.

7. The method for preventing floor heave in coal mine roadways based on floor blasting pressure relief as described in claim 1, characterized in that, In step S3, the explosive charge and the adhesive material are respectively packaged into an integrated explosive charge using plastic packaging.

8. The method for preventing floor heave in coal mine roadways based on floor blasting pressure relief as described in claim 1, characterized in that, In S2, the blasting and breaking range areas of adjacent cross-sections of the blasting boreholes are tangent or have overlapping portions.

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