Method for supporting soft rock roadway of coal mine well

Abstract

The invention discloses a soft rock roadway supporting method for a coal mine well, and relates to the technical field of mine roadway supporting, and the method comprises the following steps: S1, instrument preparation: determining the type of a used anchor rod, S2, soft rock treatment: arranging a sound wave transmitting and receiving device in soft rock, and detecting by utilizing the propagation characteristics of sound waves in the soft rock, the position of an anchor rod hole is accurately calibrated on the surrounding rock of the roadway, S4, an anchor rod is installed, specifically, an anchoring agent is gradually fed into the eye ground through the anchor rod, it is ensured that the anchoring agent is placed in place, and a drilling machine and the anchor rod are connected through a special stirring head, S5, a support is installed, specifically, an embedded part and U-shaped steel are prepared; s6, inner wall reinforcement, wherein anchor nets are laid between every two adjacent sets of arched supports; the sound wave detection device is installed, the size and distribution of gap cracks in the soft rock stratum can be accurately detected, cement paste is poured into the gaps, the gaps are filled through diffusion and solidification of the cement paste, and therefore the overall strength and stability of the soft rock are improved.

Description

Technical Field

[0001] The invention relates to the technical field of mine tunnel support, and in particular to a method for supporting soft rock tunnels in coal mines. Background Art

[0002] The geological conditions in soft rock tunnels are complex. The tunnel surrounding rock is weak and easily deformed, and the bedding and joints are well developed and easily broken and collapsed. During mining activities, the roof is often broken and seriously dropped due to poor cementation. The bottom plate is affected by the stress of the surrounding rock and the characteristics of mudstone swelling when it encounters water. The change of the bottom bulge is very obvious, resulting in the height and width not meeting the standards during the tunnel construction process. The impact is even greater during the large-section construction at the interface between the pilot tunnel and the working tunnel, resulting in particularly serious side bulge and bottom bulge in the tunnel. In addition, the water seepage from the roof causes serious mudification of the bottom plate, which also seriously affects the safety of personnel during tunnel excavation and installation of equipment on the comprehensive mining face. Therefore, it is necessary to support the soft rock tunnel;

[0003] According to the invention patent with the patent publication number CN 103334779 A, ​​a method for constructing a soft rock tunnel support with homogeneous surrounding rock is proposed. Anchor grouting support is adopted, and grouting anchor rods are placed in the tunnel surrounding rock, and pressurized cement slurry is injected. A cement spraying layer with steel wire rope as the radial bone is arranged on the tunnel surface as a sealing layer. Before implementing anchor grouting support, a reasonable replacement technology is adopted. When excavating the tunnel section, the extremely soft rock, rock with rich cracks, and rock loosened under the action of external force are replaced with sprayed concrete to form a replacement type surrounding rock body. The concrete is a strong concrete with steel wire rope as the ribs, and the replacement type surrounding rock body is uniformly implanted with multiple layers of anchor rods. The anchor rods are connected and combined with the steel wire rope in the concrete to form an anchor rod group. The support effect of the present invention is more stable than that of the existing support technology;

[0004] When dealing with soft rock in the mine tunnel, this support method only sprays grouting on the surface to provide solidification support. However, the soft rock layer is generally thick and has many cracks on its surface. The traditional direct spraying method can only attach a thin layer of concrete on the surface of the soft rock layer, which cannot provide effective support for the entire soft rock layer. In addition, the surface spraying method makes it difficult for concrete to penetrate into the cracks on the soft rock layer, which will result in poor viscosity of the support spraying layer. Summary of the invention

[0005] The purpose of the present invention is to solve the deficiencies in real life, so a method for supporting soft rock tunnels in coal mines is proposed to solve the above-mentioned problems.

[0006] The specific technical solutions adopted are as follows:

[0007] Support methods include the following:

[0008] S1 Equipment preparation: According to the geological conditions of the mine, the shape and size of the tunnel section, and the nature of the surrounding rock, determine the type, length, diameter, spacing of the anchor rods used, as well as the material, coverage area, and wire diameter of the anchor net used, and then prepare the auxiliary equipment for installing and reinforcing the anchor rods and anchor nets, and ensure that the quality and performance of these equipment meet the requirements, and conduct a safety inspection of the construction area before carrying out support work;

[0009] S2 Soft rock processing: arrange acoustic wave transmitting and receiving devices in soft rock, use the propagation characteristics of acoustic waves in soft rock for detection, and measure the propagation speed and amplitude of acoustic waves in rock;

[0010] S3: Drill anchor holes: According to the design requirements, accurately mark the position of the anchor hole on the surrounding rock of the tunnel, use laser pointing for calibration, and use the anchor drilling rig with the corresponding drill rod and drill bit to drill holes. When drilling, turn on the water first and then the air. When shutting down, stop the air first and then the water. Control the drilling angle and depth to ensure that the anchor hole meets the design requirements. At the same time, mark the drill rod to control the hole depth.

[0011] S4 Anchor bolt installation: Use compressed air to blow away the accumulated water and rock powder in the anchor bolt eye to ensure that the hole is clean and dry. The operator must be on one side of the hole mouth during the operation to ensure that there is no person in front of the hole. After completing the hole cleaning operation, put the anchoring agent into the anchor bolt eye and use the anchor bolt to gradually send the anchoring agent into the bottom of the eye to ensure that the anchoring agent is placed in place. Use a special mixing head to connect the drilling rig and the anchor bolt;

[0012] S5 bracket installation: prepare embedded parts and U-shaped steel, and cut the U-shaped steel into corresponding sections according to the size and shape of the tunnel to fit the inner wall of the tunnel. Use a pile driver to insert the embedded parts on the ground, then pour concrete, and then lay the U-shaped steel to form an arch bracket;

[0013] S6 inner wall reinforcement: Anchor nets are laid between every two adjacent sets of arch supports, and holes are drilled in the mesh of the anchor nets and anchor rods are inserted. Concrete is then poured to fix the anchor rods. After the anchor rods and the anchor nets are fixed, cement slurry is evenly sprayed on the surface of the anchor net using a nozzle, and then it is left to be fixed.

[0014] Preferably, in step S1, during the equipment preparation operation, the safety inspection of the construction area includes checking the stability of the roof and the side walls of the tunnel, and whether there is a risk of gas accumulation and water seepage, so as to ensure the safety of the construction environment.

[0015] Preferably, in step S2, in the soft rock processing operation, a flexible iron sheet is used to cover the surface of the gap to be filled, and a hole is opened in the flexible iron sheet, a grouting pipe is inserted into the hole, and cement slurry is injected into the hole through a grouting device, and the grouting pressure and grouting amount are controlled to allow the slurry to fully fill the cracks and surrounding pores. The slurry diffuses and solidifies in the cracks, cements the broken rock particles together, fills the cracks and pores, thereby improving the overall strength and stability of the soft rock and reducing the further expansion of the cracks. Finally, after the slurry solidifies, the reinforcement effect is tested by drilling and coring.

[0016] Preferably, in step S2, in the soft rock processing operation, the existence and development degree of cracks are judged according to the real-time changes of the acoustic wave transmission data, and the data changes at different positions are plotted and displayed on a drawing, so as to find out the distribution of voids and cracks on the soft rock layer, and then cement slurry is injected into the cracks.

[0017] Preferably, in step S4, during the anchor installation operation, after completing the connection operation between the drilling rig and the anchor, the drilling rig is raised, and the anchor is pushed forward while stirring so that the anchoring agent is fully and evenly stirred. The stirring time and the pushing speed should be controlled according to the type of anchor. After the anchor solidifies, the anchor tray and nut are installed, and the nut is tightened with a wrench so that the anchor tray is close to the surface of the surrounding rock to apply a pre-tightening force to the anchor.

[0018] Preferably, in step S5, during the bracket installation operation, a fixer is used to connect the U-shaped steel to the embedded parts exposed on the ground to ensure its stability, and then the U-shaped steel segments are connected along the inner wall of the tunnel, and the fixing method is to lock and fix them with bolts and nuts, and so on, the U-shaped steel is evenly laid in the tunnel according to the predetermined spacing.

[0019] Preferably, in step S6, in the inner wall reinforcement operation, the anchor material used is grade three steel bars, the mortar anchor adopts a strength grade of not less than 30 MPa, the grouting pressure is 0.4 MPa, the materials are prepared according to the above data regulations, and straightening, rust removal and degreasing are carried out to ensure the construction quality of the mortar anchor and the smooth progress of the construction.

[0020] Preferably, in step S6, during the inner wall reinforcement operation, when drilling, in order to prevent the residual water, rock powder, gravel and other debris in the hole from affecting the grouting quality and hindering the insertion of the anchor rod body, high-pressure wind and water are used to remove the water and rock powder and debris in the hole before the anchor rod is installed.

[0021] Preferably, in step S5, during the bracket installation operation, a hole is punched on the side of the arch bracket, a steel pipe is inserted into the hole, and the intersection of the steel pipe and the hole is sealed with cement slurry. When laying the next section of the arch bracket, the exposed steel pipe is then inserted into the hole on the next section of the arch bracket, thereby achieving the effect of rapid positioning and strengthening the bracket.

[0022] Compared with the prior art, the present invention has the following beneficial effects:

[0023] 1. The present invention installs an acoustic wave detection device on the rock layer in advance, and utilizes the different propagation characteristics of acoustic waves in different media to accurately detect the size and distribution of voids and cracks in the soft rock layer, and injects cement slurry into the voids. The gaps are filled by the diffusion and solidification of the cement slurry, thereby improving the overall strength and stability of the soft rock. After completing the operation, multiple sections of U-shaped steel are connected to each other to form an arch support to provide a fitting support for the inner wall of the mine tunnel, which can effectively prevent the collapse of the mine tunnel. Anchor nets are further laid on the inner wall of the mine tunnel, and concrete-fixed anchor rods are inserted into the holes of the anchor nets. The anchor rods provide a fixing measure for the anchor net, and the tension of the anchor net can be increased by inserting them into the mesh holes. Finally, cement slurry is sprayed on the surface of the installed anchor net, thereby strengthening the support strength of the tunnel wall.

[0024] 2. The present invention arranges perforations and steel pipes on the side of the arch support, and the end perforations of the steel pipes are plugged into each other and sealed and fixed with cement slurry, so that a section of the steel pipe is reserved outside. The reserved length is the same as the distribution spacing of the arch support. When installing the next section of the arch support, the perforations of the next section of the arch support can be directly plugged into the exposed steel pipe, thereby eliminating the positioning process, and the interconnected steel pipes can also increase the firmness of the installation of the arch support. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 The present invention is a schematic diagram of a process flow of a method for supporting soft rock tunnels in a coal mine. DETAILED DESCRIPTION

[0026] The technical solutions in the embodiments of the present invention will be described clearly and completely below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, rather than all the embodiments.

[0027] Embodiment 1:

[0028] like Figure 1 As shown, a method for supporting soft rock tunnels in coal mines, the supporting method includes the following:

[0029] S1 Equipment preparation: According to the geological conditions of the mine, the shape and size of the tunnel section, and the nature of the surrounding rock, determine the type, length, diameter, spacing of the anchor rods used, as well as the material, coverage area, and wire diameter of the anchor net used, and then prepare the auxiliary equipment for installing and reinforcing the anchor rods and anchor nets, and ensure that the quality and performance of these equipment meet the requirements, and conduct a safety inspection of the construction area before carrying out support work;

[0030] S2 Soft rock processing: arrange acoustic wave transmitting and receiving devices in soft rock, use the propagation characteristics of acoustic waves in soft rock for detection, and measure the propagation speed and amplitude of acoustic waves in rock;

[0031] S3: Drill anchor holes: According to the design requirements, accurately mark the position of the anchor hole on the surrounding rock of the tunnel, use laser pointing for calibration, and use the anchor drilling rig with the corresponding drill rod and drill bit to drill holes. When drilling, turn on the water first and then the air. When shutting down, stop the air first and then the water. Control the drilling angle and depth to ensure that the anchor hole meets the design requirements. At the same time, mark the drill rod to control the hole depth.

[0032] S4 Anchor bolt installation: Use compressed air to blow away the accumulated water and rock powder in the anchor bolt eye to ensure that the hole is clean and dry. The operator must be on one side of the hole mouth during the operation to ensure that there is no person in front of the hole. After completing the hole cleaning operation, put the anchoring agent into the anchor bolt eye and use the anchor bolt to gradually send the anchoring agent into the bottom of the eye to ensure that the anchoring agent is placed in place. Use a special mixing head to connect the drilling rig and the anchor bolt;

[0033] S5 bracket installation: prepare embedded parts and U-shaped steel, and cut the U-shaped steel into corresponding sections according to the size and shape of the tunnel to fit the inner wall of the tunnel. Use a pile driver to insert the embedded parts on the ground, then pour concrete, and then lay the U-shaped steel to form an arch bracket;

[0034] S6 inner wall reinforcement: Anchor nets are laid between every two adjacent sets of arch supports, and holes are drilled in the mesh of the anchor nets and anchor rods are inserted. Concrete is then poured to fix the anchor rods. After the anchor rods and the anchor nets are fixed, cement slurry is evenly sprayed on the surface of the anchor net using a nozzle, and then it is left to be fixed.

[0035] Specifically, in step S1, during the equipment preparation operation, the safety inspection of the construction area includes checking the stability of the roof and the side walls of the tunnel, and whether there is a risk of gas accumulation and water seepage, so as to ensure the safety of the construction environment.

[0036] Specifically, in step S2, in the soft rock processing operation, a flexible iron sheet is used to cover the surface of the gap to be filled, and a hole is opened on the flexible iron sheet, a grouting pipe is inserted into the hole, and cement slurry is injected into the hole through a grouting device, and the grouting pressure and grouting amount are controlled to allow the slurry to fully fill the cracks and surrounding pores. The slurry diffuses and solidifies in the cracks, cements the broken rock particles together, fills the cracks and pores, thereby improving the overall strength and stability of the soft rock and reducing the further expansion of the cracks. Finally, after the slurry solidifies, the reinforcement effect is tested by drilling and coring.

[0037] Specifically, in step S2, during the soft rock processing operation, the existence and development degree of cracks are judged according to the real-time changes of the acoustic wave transmission data, and the data changes at different positions are plotted and displayed on a drawing, so as to find out the distribution of voids and cracks on the soft rock layer, and then inject cement slurry into the cracks.

[0038] Specifically, in step S4, during the anchor installation operation, after completing the connection operation between the drilling rig and the anchor, the drilling rig is raised, and the anchor is pushed forward while stirring to ensure that the anchoring agent is fully and evenly stirred. The stirring time and the pushing speed should be controlled according to the type of anchor. After the anchor solidifies, the anchor tray and the nut are installed, and the nut is tightened with a wrench to make the anchor tray close to the surface of the surrounding rock and apply a pre-tightening force to the anchor.

[0039] Specifically, in step S5, during the bracket installation operation, a fixer is used to connect the U-shaped steel to the embedded parts exposed on the ground to ensure its stability, and then the U-shaped steel segments are connected along the inner wall of the tunnel, and the fixing method is to lock and fix them with bolts and nuts, and so on, the U-shaped steel is evenly laid in the tunnel according to the predetermined spacing.

[0040] As can be seen from the above, this method can accurately detect the size and distribution of voids and cracks in soft rock formations by installing an acoustic wave detection device on the rock formation in advance and utilizing the different propagation characteristics of acoustic waves in different media, and inject cement slurry into the voids. The gaps are filled by utilizing the diffusion and solidification of the cement slurry, thereby improving the overall strength and stability of the soft rock. After completing this operation, multiple sections of U-shaped steel are connected to each other to form an arch support to provide a fitting support for the inner wall of the mine tunnel, which can effectively prevent the collapse of the mine tunnel. Anchor nets are further laid on the inner wall of the mine tunnel, and concrete-fixed anchor rods are inserted into the holes of the anchor nets. The anchor rods provide a fixing measure for the anchor nets, and the tension of the anchor nets can be increased by inserting them into the mesh holes. Finally, cement slurry is sprayed on the surface of the installed anchor nets, thereby strengthening the support strength of the tunnel walls.

[0041] Embodiment 2:

[0042] like Figure 1As shown, in step S6, in the inner wall reinforcement operation, the anchor material used is grade three steel bars, the mortar anchor adopts a strength grade of not less than 30MPa, and the grouting pressure is 0.4MPa. The materials are prepared according to the above data regulations, and straightening, rust removal and degreasing are carried out to ensure the construction quality of the mortar anchor and the smooth progress of the construction.

[0043] Specifically, in step S6, during the inner wall reinforcement operation, when drilling, in order to prevent the residual water, rock powder, and gravel debris in the hole from affecting the grouting quality and hindering the insertion of the anchor rod body, high-pressure wind and water are used to remove the water and rock powder debris in the hole before the anchor is installed.

[0044] Specifically, in step S5, during the bracket installation operation, a hole is punched on the side of the arch bracket, a steel pipe is inserted into the hole, and the intersection of the steel pipe and the hole is sealed with cement slurry. When laying the next section of the arch bracket, the exposed steel pipe is then inserted into the hole on the next section of the arch bracket, thereby achieving the effect of rapid positioning and reinforcement of the bracket.

[0045] As can be seen from the above, the present invention sets perforations and steel pipes on the side of the arch support, and the end perforations of the steel pipes are plugged into each other and sealed and fixed with cement slurry, so that a section of the steel pipe is reserved outside. The reserved length is the same as the distribution spacing of the arch support. When installing the next section of the arch support, the perforations of the next section of the arch support can be directly plugged into the exposed steel pipe, thereby eliminating the positioning process, and the interconnected steel pipes can also increase the firmness of the installation of the arch support.

[0046] The above is only a preferred specific embodiment of the present invention, but the protection scope of the present invention is not limited thereto. The replacement may be a replacement of a part of the structure, device, method step, or a complete technical solution. Any equivalent replacement or change according to the technical solution and the inventive concept of the present invention shall be covered within the protection scope of the present invention.

Claims

1. A method for supporting soft rock tunnels in coal mines, characterized in that: The following steps are involved: S1 Equipment preparation: According to the geological conditions of the mine, the shape and size of the tunnel section, and the nature of the surrounding rock, determine the type, length, diameter, spacing of the anchor rods used, as well as the material, coverage area, and wire diameter of the anchor net used, and then prepare the auxiliary equipment for installing and reinforcing the anchor rods and anchor nets, and ensure that the quality and performance of these equipment meet the requirements, and conduct a safety inspection of the construction area before carrying out support work; S2 Soft rock processing: arrange acoustic wave transmitting and receiving devices in soft rock, use the propagation characteristics of acoustic waves in soft rock for detection, and measure the propagation speed and amplitude of acoustic waves in rock; S3: Drill anchor holes: According to the design requirements, accurately mark the position of the anchor hole on the surrounding rock of the tunnel, use laser pointing for calibration, and use the anchor drilling rig with the corresponding drill rod and drill bit to drill holes. When drilling, turn on the water first and then the air. When shutting down, stop the air first and then the water. Control the drilling angle and depth to ensure that the anchor hole meets the design requirements. At the same time, mark the drill rod to control the hole depth. S4 Anchor bolt installation: Use compressed air to blow away the accumulated water and rock powder in the anchor bolt eye to ensure that the hole is clean and dry. The operator must be on one side of the hole mouth during the operation to ensure that there is no person in front of the hole. After completing the hole cleaning operation, put the anchoring agent into the anchor bolt eye and use the anchor bolt to gradually send the anchoring agent into the bottom of the eye to ensure that the anchoring agent is placed in place. Use a special mixing head to connect the drilling rig and the anchor bolt; S5 bracket installation: prepare embedded parts and U-shaped steel, and cut the U-shaped steel into corresponding sections according to the size and shape of the tunnel to fit the inner wall of the tunnel. Use a pile driver to insert the embedded parts on the ground, then pour concrete, and then lay the U-shaped steel to form an arch bracket; S6 inner wall reinforcement: Anchor nets are laid between every two adjacent sets of arch supports, and holes are drilled in the mesh of the anchor nets and anchor rods are inserted. Concrete is then poured to fix the anchor rods. After the anchor rods and the anchor nets are fixed, cement slurry is evenly sprayed on the surface of the anchor net using a nozzle, and then it is left to be fixed.

2. A method for supporting soft rock tunnels in coal mines as claimed in claim 1, characterized in that: In step S1, during the equipment preparation operation, the safety inspection of the construction area includes checking the stability of the roof and the side walls of the tunnel, and whether there is a risk of gas accumulation and water seepage, so as to ensure the safety of the construction environment.

3. A method for supporting soft rock tunnels in coal mines as claimed in claim 1, characterized in that: In step S2, in the soft rock processing operation, a flexible iron sheet is used to cover the surface of the gap to be filled, and a hole is opened on the flexible iron sheet. A grouting pipe is inserted into the hole, and cement slurry is injected into the hole through a grouting device. The grouting pressure and grouting amount are controlled to allow the slurry to fully fill the cracks and surrounding pores. The slurry diffuses and solidifies in the cracks, cements the broken rock particles together, fills the cracks and pores, thereby improving the overall strength and stability of the soft rock and reducing the further expansion of the cracks. Finally, after the slurry solidifies, the reinforcement effect is tested by drilling and coring.

4. A method for supporting soft rock tunnels in coal mines as claimed in claim 1, characterized in that: In step S2, during the soft rock processing operation, the existence and development degree of cracks are judged according to the real-time changes of the acoustic wave transmission data, and the data changes at different positions are plotted and displayed on a drawing, so as to find out the distribution of voids and cracks on the soft rock layer, and then cement slurry is injected into the cracks.

5. A method for supporting soft rock tunnels in coal mines as claimed in claim 1, characterized in that: In step S4, during the anchor installation operation, after completing the connection operation between the drill rig and the anchor, the drill rig is raised again, and the anchor is pushed forward while stirring to ensure that the anchoring agent is fully and evenly stirred. The stirring time and the pushing speed should be controlled according to the type of anchor. After the anchor solidifies, the anchor tray and nut are installed, and the nut is tightened with a wrench to make the anchor tray close to the surface of the surrounding rock and apply a pre-tightening force to the anchor.

6. A method for supporting soft rock tunnels in coal mines as claimed in claim 1, characterized in that: In step S5, during the bracket installation operation, a fixer is used to connect the U-shaped steel to the embedded parts exposed on the ground to ensure its stability, and then the U-shaped steel segments are connected along the inner wall of the tunnel. Bolts and nuts are used to lock and fix them, and the U-shaped steel is evenly laid in the tunnel according to the predetermined spacing.

7. A method for supporting soft rock tunnels in coal mines as claimed in claim 1, characterized in that: In step S6, during the inner wall reinforcement operation, the anchor material used is grade three steel bars, the mortar anchor has a strength grade of not less than 30MPa, and the grouting pressure is 0.4MPa. The materials are prepared according to the above data, and straightening, rust removal and oil removal are performed to ensure the construction quality of the mortar anchor and the smooth progress of the construction.

8. A method for supporting soft rock tunnels in coal mines as claimed in claim 1, characterized in that: In step S6, during the inner wall reinforcement operation, when drilling, in order to prevent the residual water, rock powder, and gravel debris in the hole from affecting the grouting quality and hindering the insertion of the anchor rod body, high-pressure wind and water are used to remove the water and rock powder debris in the hole before the anchor is installed.

9. A method for supporting soft rock tunnels in coal mines as claimed in claim 1, characterized in that: In step S5, during the bracket installation operation, a hole is punched on the side of the arch bracket, a steel pipe is inserted into the hole, and the intersection of the steel pipe and the hole is sealed with cement slurry. When laying the next section of the arch bracket, the exposed steel pipe is then inserted into the hole on the next section of the arch bracket, thereby achieving the effect of rapid positioning and reinforcement of the bracket.

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