Treatment method for floor heave and bottom plate of expansive mudstone roadway

Abstract

The invention relates to the technical field of coal mine roadway surrounding rock control, in particular to a treatment method for a floor heave and a bottom plate of an expansive mudstone roadway. Comprising the steps that a roadway argillaceous bottom plate stability control mechanical model is established, the angle a and the length L of an advanced fixed spraying plate are obtained, and a double-hole guniting drill bit is selected; a first drill hole and a second drill hole are formed in the two bottom corners of the roadway in the designed tunneling direction of the tunneling working face through a double-hole guniting drill bit; the direction of the guniting hole is adjusted, the double-hole guniting drill bit is driven to retreat in the first drill hole and / or the second drill hole and carry out directional guniting, the directional guniting is green modified slurry, a first advanced fixed spraying plate and a first terrace with an angle a are formed in the first drill hole, and a second advanced fixed spraying plate and a second terrace with an angle a are formed in the second drill hole; and the first terrace is in lap joint with the second terrace. Therefore, the problems that the expansion mudstone bottom plate of the coal seam roadway is large in deformation under the coupling action of mining-induced stress and underground water, and roadway floor heave control and treatment are difficult are solved.

Description

Technical Field

[0001] This invention relates to the field of coal mine roadway surrounding rock control technology, and more specifically, to a method for treating floor heave and floor slab in expansive mudstone roadways. Background Technology

[0002] The treatment of floor heave in coal mine roadways is fundamental to ensuring safe and efficient production. However, the treatment of floor heave, especially in expansive mudstone floors, still faces numerous challenges. Because the mudstone floor is extremely soft and fractured, it easily absorbs water and expands, resulting in softening and mudification. Furthermore, due to the extremely complex geological structure and the environmental influence of mining-induced stress, stress concentration and redistribution easily occur, leading to severe floor heave. This phenomenon causes severe deformation of the floor, affecting the efficiency of tunneling and transportation in coal mine roadways, increasing production costs, and posing a serious threat to safe and efficient mine production.

[0003] Currently, the main methods for controlling the stability of expansive mudstone floor slabs in roadways, which has long plagued safe and efficient coal mine production, are active reinforcement and stress control. Active reinforcement methods include reverse arching, floor anchor (cable) support, grouting, and chemical curing agents; stress control methods (pressure relief methods) mainly include borehole pressure relief, pre-splitting blasting pressure relief, and floor slotting pressure relief. While these two methods have achieved some success in controlling and treating floor heave, they present several problems for expansive mudstone floor slabs. First, the anchoring effect of the soft mudstone floor slab is poor, the low porosity of the mudstone makes it difficult to inject grout, resulting in ineffective grouting. Simultaneously, the mudstone floor swells upon contact with water, leading to large heave volumes; the pressure relief method only reduces and transfers the stress in the floor slab but cannot control water-swellable floor heave. Summary of the Invention

[0004] To address the problem of large deformation of expansive mudstone floor slabs in coal seam roadways under the coupled effects of mining stress and groundwater, and the difficulty in controlling and treating floor heave, this invention provides a method for treating floor heave and floor slabs in expansive mudstone roadways. By developing a new type of modified slurry, optimizing the interaction between the slurry and the mudstone floor slab, and combining it with stress control technology, effective control and treatment of floor heave can be achieved, truly solving the problem of large deformation of expansive mudstone floor slabs in coal seam roadways under the coupled effects of mining stress and groundwater, and the difficulty in controlling and treating floor heave.

[0005] This invention provides a method for treating floor heave and floor slab in expansive mudstone roadways, comprising:

[0006] S1. Establish a mechanical model for the stability control of the muddy floor of the tunnel, obtain the angle α and length L of the advance fixed spraying plate, and select a double-hole spraying drill bit based on the angle α of the advance fixed spraying plate.

[0007] S2, in the development, preparation or mining roadway, the first and second boreholes are formed by using a double-hole shotcrete drill bit at the two bottom corners of the roadway along the designed tunneling direction of the tunneling face.

[0008] S3, adjust the direction of the grouting holes of the dual-hole grouting drill bit, drive the dual-hole grouting drill bit to retract in the first drill hole and / or the second drill hole and carry out directional grouting, wherein the directional grouting is a green modified slurry containing cationic modified resin; wherein, a first advanced fixed-point grouting plate and a first ground surface with an angle α are formed in the first drill hole, and the included angle between the first advanced fixed-point grouting plate and the first ground surface is greater than 90 degrees; and, a second advanced fixed-point grouting plate and a second ground surface with an angle α are formed in the second drill hole, and the included angle between the second advanced fixed-point grouting plate and the second ground surface is greater than 90 degrees; the first ground surface overlaps with the second ground surface, and the first advanced fixed-point grouting plate and the second advanced fixed-point grouting plate form the advanced fixed-point grouting plate.

[0009] In some embodiments, in step S3, the green modified slurry material includes: silicate cement content of 40%~50%, fly ash content of 30%~40%, water-soluble sodium-type cation exchange resin content of 5%~10%, and the spraying material is mixed with water at a 1:1 ratio.

[0010] In some embodiments, the mechanical model for stabilizing the muddy floor of the roadway is as follows:

[0011] ;

[0012] In the formula, φ' is the internal friction angle of the loose coal seam in the roof, and φ is the internal friction angle of the muddy floor.

[0013] In some embodiments, in step S3, when the dual-hole jetting drill bit retracts in the first and / or second borehole, the retraction speed is less than or equal to 0.4 m / min.

[0014] In some embodiments, the dual-hole shotcrete drill bit has a flow channel in the middle, and two shotcrete holes are also provided through the dual-hole shotcrete drill bit. The two shotcrete holes are respectively connected to the flow channel, and the central axes of the two shotcrete holes intersect.

[0015] To address the problem of large deformation of the expansive mudstone floor in coal seam roadways under the coupled effects of mining stress and groundwater, and the difficulty in controlling and treating roadway floor heave, this invention has the following advantages:

[0016] The technical solution of this invention utilizes a dual-hole grouting drill bit to withdraw from the first and second boreholes and perform directional grouting. After the grout solidifies, a first pre-spraying plate and a first floor, a second pre-spraying plate and a second floor are formed respectively. The first floor and the second floor overlap to form a complete floor, which can seal and strengthen the mudstone base. The pre-spraying plate can effectively cut off the stress propagation path of the base rock layer and act as a water-stop curtain to cut off the water source, preventing the base rock layer from sliding. The hydrophobic cationic modified resin in the green modified grout penetrates into the expansive mudstone around the solidified floor and the pre-spraying plate to achieve modification and inhibit the expansion characteristics of the mudstone. Attached Figure Description

[0017] Figure 1 A flowchart illustrating a method for treating floor heave and floor slab in expansive mudstone roadways is shown.

[0018] Figure 2 A schematic diagram shows a complete set of equipment for stabilizing expansive mudstone floor during directional shotcrete modification-reinforcement-decompression construction at the tunneling face;

[0019] Figure 3 A cross-sectional schematic diagram of the pre-spraying reinforcement at the bottom corner of the base plate is shown;

[0020] Figure 4 A schematic diagram of the structure of a dual-hole shotcrete drill bit is shown;

[0021] Figure 5 A schematic diagram of the mechanical model for stabilizing the muddy floor of a roadway is shown.

[0022] Reference numerals: 1-Tunneling face; 2-Integrated drilling and grouting rig; 3-High-pressure grouting pump; 4-Grouting system; 5-Intelligent control system; 6-Hollow drill rod; 7-Grouting sealing plug; 8-Double-hole grouting drill bit; 9-Pre-grouting reinforcement zone of the floor; 10-Direct roof; 11-Coal seam; 12-Direct floor of expansive mudstone; 13-Tunnel cross-section outline; 14-First borehole; 15-First pre-grouting plate; 16-First ground level; 17-Second borehole; 18-Second pre-grouting plate; 19-Second ground level; 21-Expansive mudstone modification zone; 22-Grouting hole. Detailed Implementation

[0023] The present disclosure will now be discussed with reference to several exemplary embodiments. It should be understood that these embodiments are discussed only to enable those skilled in the art to better understand and thus implement the present disclosure, and are not intended to imply any limitation on the scope of the disclosure.

[0024] As used herein, the term "comprising" and its variations are to be interpreted as open-ended terms meaning "including but not limited to". The term "based on" is to be interpreted as "at least partially based on". The terms "one embodiment" and "an embodiment" are to be interpreted as "at least one embodiment". The term "another embodiment" is to be interpreted as "at least one other embodiment". The terms "upper", "lower", "left", "right", "front", "rear", "top", "bottom", "inner", "outer", "vertical", "horizontal", "lateral", "longitudinal", etc., indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings. These terms are primarily used to better describe this application and its embodiments and are not intended to limit the indicated devices, elements, or components to include a specific orientation or to be constructed and operated in a specific orientation. Furthermore, some of the above terms may be used to indicate other meanings besides orientations or positional relationships; for example, the term "upper" may in some cases indicate a dependency or connection relationship. Those skilled in the art can understand the specific meaning of these terms in this application according to the specific circumstances. In addition, the terms "installed", "set up", "equipped with", "connected", and "linked" should be interpreted broadly. For example, it can be a connection, a detachable connection, or an integral structure; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium, or an internal connection between two devices, elements, or components. Those skilled in the art can understand the specific meaning of the above terms in this application according to the specific circumstances. Furthermore, the terms "first," "second," etc., are mainly used to distinguish different devices, elements, or components (the specific types and structures may be the same or different), and are not used to indicate or imply the relative importance or quantity of the indicated devices, elements, or components. Unless otherwise stated, "a plurality of" means two or more.

[0025] This embodiment discloses a method for treating floor heave and floor slab in expansive mudstone roadways, such as... Figures 1 to 5 As shown, the treatment method for floor bulging and floor slab in the expansive mudstone roadway includes:

[0026] S1. Establish a mechanical model for the stability control of the muddy floor of the tunnel, obtain the angle a and length L of the advance fixed spraying plate, and select the double-hole spraying drill bit 8 according to the angle a of the advance fixed spraying plate.

[0027] S2, in the development, preparation or mining roadway, the first borehole 14 and the second borehole 17 are formed by using a double-hole shotcrete drill bit 8 at the two bottom corners of the roadway along the designed tunneling direction of the tunneling face 1.

[0028] S3, adjust the direction of the grouting hole 22 of the dual-hole grouting drill bit 8, drive the dual-hole grouting drill bit 8 to retract and perform directional grouting in the first drill hole 14 and / or the second drill hole 17, the directional grouting is a green modified slurry, the green modified slurry contains cationic modified resin; wherein, a first advanced fixed grouting plate 15 and a first ground 16 with an angle α are formed in the first drill hole 14, the included angle between the first advanced fixed grouting plate 15 and the first ground 16 is greater than 90 degrees; and, a second advanced fixed grouting plate 18 and a second ground 19 with an angle α are formed in the second drill hole 17, the included angle between the second advanced fixed grouting plate 18 and the second ground 19 is greater than 90 degrees; the first ground 16 and the second ground 19 overlap, the first advanced fixed grouting plate 15 and the second advanced fixed grouting plate 18 form the advanced fixed grouting plate.

[0029] In this embodiment, a method for treating the floor heave and floor slab of expansive mudstone roadways is provided, applied to a complete set of equipment for stabilizing expansive mudstone floor slabs. Specifically, a dual-hole grouting drill bit 8 is used to withdraw the drill bit in the first borehole 14 and the second borehole 17 and perform directional grouting. After the grout solidifies, a first pre-grouting plate 15 and a first ground slab 16, a second pre-grouting plate 18, and a second ground slab 19 are formed, respectively. The first ground slab 16 and the second ground slab 19 overlap to form a complete ground slab, which can seal and strengthen the mudstone floor slab. The pre-grouting plate can effectively cut off the stress propagation path of the floor slab and act as a water-stop curtain to cut off the water source, preventing floor slab slippage. The hydrophobic cationic modified resin in the green modified grout penetrates into the expansive mudstone surrounding the solidified ground slab and the pre-grouting plate, achieving modification and inhibiting the mudstone's expansion characteristics.

[0030] Specifically, a complete set of equipment for stabilizing expansive mudstone floor is an intelligent integrated drilling and grouting system, such as... Figure 2 As shown, the complete set of equipment is used for drilling and shotcreting at the bottom corner of the tunneling face 1, with a slope angle of 45°. The equipment includes an integrated drilling and shotcreting rig 2, a high-pressure grouting pump 3, a grout supply system 4, and an intelligent control system 5. Besides the main body of the rig, the integrated drilling and shotcreting rig 2 mainly consists of a hollow drill rod 6, a grout sealing plug 7, and a dual-hole shotcreting drill bit 8. By drilling to the designed depth, adjusting the direction of the shotcreting holes 22, and retracting the drill bit, directional shotcreting is carried out to form a pre-shotcreting reinforcement zone 9 for the bottom plate. Among them, the high-pressure grouting pump 3 can provide a grouting pressure of over 20MPa, the grouting supply system 4 can continuously stir, recover and filter the grouting material, the intelligent control system 5 can accurately and intelligently control the direction and pressure of the drilling nozzle for directional grouting, the drilling and grouting integrated drilling rig 2 integrates drilling and directional grouting functions, the hollow drill rod 6 is equipped with a double-hole grouting drill bit 8 for grouting, the high-pressure grouting pump 3 can provide a high grouting pressure, the grouting supply system 4 can continuously stir, recover and filter the grouting material, and the intelligent control system 5 can accurately and intelligently control the direction of the drilling nozzle for directional grouting.

[0031] Specifically, before drilling, retraction, and directional shotcreting, it is necessary to determine the angle α and length L of the pre-shotcreting plate using a mechanical model. Therefore, it is necessary to establish a mechanical model for the stability control of the muddy floor of the tunnel, and obtain the angle α and length L of the pre-shotcreting plate based on this model. Based on the angle α of the pre-shotcreting plate, a dual-hole shotcreting drill bit 8 is selected.

[0032] To achieve stable control of the expansive mudstone base, it is necessary to design the dimensions of the pre-jet continuous slab that blocks water and cuts off the sliding path of the mudstone layers. For example... Figure 5 As shown in the diagram, the roadway in this mechanical model has a width of b and a height of H. The roadway floor collapses on both sides under a uniformly distributed load q. ABC and A'B'C' are active slip zones, while ACDE and A'C'D'E' are passive slip zones. The angle between BC and the roadway horizontal line is 45° + φ / 2, where φ is the internal friction angle of the muddy floor. The angle α of the advanced spraying plate is aligned with the AC direction, controlling the active slip zone and cutting off the slip path.

[0033] The mechanical model for the stability control of the muddy floor of this roadway is as follows:

[0034] ;

[0035] In the formula, φ' is the internal friction angle of the loose coal seam 11 in the roof.

[0036] In this application, assuming φ' and φ are both 30°, the tunnel width is b=4m and the height is H=3m, then the angle between the advanced fixed-point spraying plate and the horizontal line of the bottom plate is 60°, and the length of the fixed-point spraying plate is L≈1.28m. The length L can be adjusted by adjusting the fixed-point spraying pressure and the retraction spraying speed.

[0037] Furthermore, such as Figure 3As shown, the main process of the treatment method for the floor bulge and floor plate of the expansive mudstone roadway is as follows: After obtaining the angle α and length L of the advanced fixed-point spraying plate through the stability control mechanical model of the mudstone floor plate of the roadway, a double-hole spraying drill bit 8 of appropriate size is selected. Then, in the development, preparation or mining roadway, the first borehole 14 and the second borehole 17 are formed by constructing the double-hole spraying drill bit 8 along the designed tunneling direction of the tunneling face 1 at the two bottom corners of the roadway. Among them, the right bottom corner fixed-point spraying drill hole (i.e., the first borehole 14) is drilled at the right bottom corner position of the roadway outline to the designed depth. The direction of the spraying hole 22 of the double-hole spraying drill bit 8 is adjusted, and the green modified mudstone slurry is sprayed in a directional manner after the drill is withdrawn. The green modified slurry is ordinary cement slurry mixed with cationic modified resin. The nano-sized resin enters the <1μm cracks, and the hydrophobic cations replace the hydrophilic cations between clay mineral layers, inhibiting the water absorption and expansion between clay mineral layers. Ordinary cement is mixed with mudstone broken by high-pressure slurry to reinforce the soft mudstone. After the grout solidifies, a right bottom corner reinforcement continuous plate (i.e., the first advanced fixed-point spraying plate 15) and a right-side floor (i.e., the first floor 16) are formed. The drill rod is rotated 30° counterclockwise and moved to the left bottom corner. The left bottom corner fixed-point spraying borehole (i.e., the second borehole 17) is drilled to the designed depth. The direction of the spraying hole 22 of the double-hole spraying drill bit 8 is adjusted, and the green modified grout is sprayed directionally after the drill is withdrawn. After the grout solidifies, a left advanced fixed-point spraying plate (i.e., the second advanced fixed-point spraying plate 18) and a left-side floor (i.e., the second floor 19) are formed. The left-side floor overlaps with the right-side floor to form a complete floor. Water-soluble cations migrate to the depth of the floor, forming an expansive mudstone modification zone 21. The right bottom corner reinforcement continuous plate and the left advanced fixed-point spraying plate cut off the floor water source and the sliding path of the left and right floor rock strata, respectively. High-pressure directional spraying achieves modification of the expansive floor of the tunnel and reinforcement of key parts of the bottom corner, which is highly targeted. The cement slurry in the green modified slurry solidifies to form a floor that can seal and strengthen the muddy base. The pre-sprayed plate can effectively cut off the stress propagation path of the base rock layer and act as a water-stop curtain to cut off the water source and prevent the base rock layer from sliding. The hydrophobic cationic resin in the green modified slurry penetrates into the expansive mudstone around the solidified floor and the corner reinforcement plate to achieve modification and inhibit the expansion characteristics of the mudstone.

[0038] Furthermore, such as Figure 4As shown, to achieve the treatment method for floor heave and floor slab in expansive mudstone roadways, the double-hole shotcrete drill bit 8 is a single-tube double-hole shotcrete drill bit 8. The two shotcrete holes 22 are located on the same cross section of the drill rod, obliquely distributed at 120°, featuring a simple structure, high shotcrete efficiency, and convenient processing. The designed drilling depth is the distance of one advanced reinforcement cycle, generally designed to be 20-40 meters; the retraction speed during the fixed-shot process is 0.4 m / min. During the directional spraying of the mudstone green modified slurry in the right bottom corner fixed-shot drill hole, the left shotcrete hole 22 is horizontal, enabling the construction of the left advanced fixed-shot plate and the left floor slab in one go during the retraction process. Then, the double-hole shotcrete drill bit 8 rotates counterclockwise by 30°. During the directional spraying of the mudstone green modified slurry in the right bottom corner fixed-shot drill hole, the right shotcrete hole 22 is horizontal, enabling the construction of the left advanced fixed-shot plate and the left floor slab in one go during the retraction process. Once the slurry strength reaches the design requirements, roadway excavation begins.

[0039] To achieve stable control of expansive mudstone foundations, this green modified grout is designed for expansive argillaceous rock masses. It is an eco-friendly modified grout based on ordinary Portland cement (OPC), water-soluble sodium-type cation exchange resin, and fly ash. It achieves reinforcement of the argillaceous rock mass through the synergistic effects of physical filling, chemical cementation, and ion exchange. The ordinary Portland cement (P.O52.5) ​​content in the grout is 40%–50%, providing primary cementitious strength and solidifying to form a rigid framework; the fly ash content is 30%–40%, reducing shrinkage; and the water-soluble sodium-type cation exchange resin content is 5%–10%, penetrating the micro-fractures of the argillaceous rock mass and inhibiting clay mineral expansion through Na⁺ exchange. The grout is mixed with water at a 1:1 ratio to achieve a fluid state suitable for grouting.

[0040] In summary, the technical solution of this invention utilizes a dual-hole grouting drill bit to withdraw from the first and second boreholes and perform directional grouting. After the grout solidifies, a first pre-spraying plate and a first ground surface are formed, as well as a second pre-spraying plate and a second ground surface. The first ground surface overlaps with the second ground surface to form a complete ground surface, which can seal and strengthen the mudstone base. The pre-spraying plate can effectively cut off the stress propagation path of the base rock layer and act as a water-stop curtain to cut off the water source, preventing the base rock layer from sliding. The hydrophobic cationic modified resin in the green modified grout penetrates into the expansive mudstone around the solidified ground surface and the pre-spraying plate, achieving modification and inhibiting the expansion characteristics of the mudstone.

[0041] It will be apparent to those skilled in the art that the present invention is not limited to the details of the exemplary embodiments described above, and that the invention can be implemented in other specific forms without departing from the spirit or essential characteristics of the invention. Therefore, the embodiments should be considered in all respects as exemplary and non-limiting, and the scope of the invention is defined by the appended claims rather than the foregoing description. Thus, it is intended that all variations falling within the meaning and scope of equivalents of the claims be included within the present invention.

[0042] Furthermore, it should be understood that although this specification describes embodiments, not every embodiment contains only one independent technical solution. This narrative style of the specification is merely for clarity. Those skilled in the art should regard the specification as a whole, and the technical solutions in each embodiment can also be appropriately combined to form other implementation methods that can be understood by those skilled in the art.

Claims

1. A method for treating floor heave and floor slab in expansive mudstone roadways, characterized in that, include: S1. Establish a mechanical model for the stability control of the muddy floor of the tunnel, obtain the angle α and length L of the advance fixed spraying plate, and select a double-hole spraying drill bit based on the angle α of the advance fixed spraying plate. S2, in the development, preparation or mining roadway, the first and second boreholes are formed by using a double-hole shotcrete drill bit at the two bottom corners of the roadway along the designed tunneling direction of the tunneling face. S3, adjust the direction of the grouting holes of the dual-hole grouting drill bit, drive the dual-hole grouting drill bit to retract in the first drill hole and / or the second drill hole and carry out directional grouting, wherein the directional grouting is a green modified slurry containing cationic modified resin; wherein, a first advanced fixed-point grouting plate and a first ground surface with an angle α are formed in the first drill hole, and the included angle between the first advanced fixed-point grouting plate and the first ground surface is greater than 90 degrees; and, a second advanced fixed-point grouting plate and a second ground surface with an angle α are formed in the second drill hole, and the included angle between the second advanced fixed-point grouting plate and the second ground surface is greater than 90 degrees; the first ground surface and the second ground surface overlap.

2. The method for treating floor bulges and floor slabs in expansive mudstone roadways as described in claim 1, characterized in that, In step S3, the green modified slurry material includes: silicate cement content of 40%~50%, fly ash content of 30%~40%, water-soluble sodium-type cation exchange resin content of 5%~10%, and the spraying material is mixed with water at a ratio of 1:

1.

3. The method for treating floor bulge and floor slab in expansive mudstone roadways as described in claim 2, characterized in that, The mechanical model for stabilizing the mud floor of the roadway is as follows: ； In the formula, φ' is the internal friction angle of the loose coal seam in the roof, and φ is the internal friction angle of the muddy floor.

4. The method for treating floor bulge and floor slab in expansive mudstone roadways as described in claim 1, characterized in that, In step S3, when the dual-hole jetting drill bit retracts in the first and / or second borehole, the retraction speed is less than or equal to 0.4 m / min.

5. The method for treating floor bulge and floor slab in expansive mudstone roadways as described in claim 1, characterized in that, The dual-hole shotcrete drill bit has a flow channel in the middle, and two shotcrete holes are also provided through the dual-hole shotcrete drill bit. The two shotcrete holes are respectively connected to the flow channel, and the central axes of the two shotcrete holes intersect.

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