A method for sealing water in grouting holes for tunnel curtain grouting

Abstract

This invention relates to the field of tunnel construction technology, specifically to a water-stopping method for grouting holes in tunnel curtain grouting. The method employs a water-stopping device inserted into the grouting hole, comprising: S1: pausing drill bit advance; S2: pressurizing the expansion bladder to inflate it and press it tightly against the inner wall of the grouting hole; S3: injecting grout into the drill rod, pausing and stabilizing the pressure after the grout pressure reaches a first preset pressure; S4: reducing the pressure of the expansion bladder; S5: continuing grouting at the first preset pressure until only grout flows out of the grouting hole opening; S6: repressurizing the expansion bladder until there is no water seepage and no grout flow at the grouting hole opening, simultaneously stopping grouting and stabilizing the pressure. This method can utilize the drill rod for small-scale curtain grouting as temporary borehole protection, replacing existing sealing measures that rely solely on mechanical expansion with solidified grout in the grouting hole, effectively coping with high-pressure water inrush environments, and achieving good water-stopping results.

Description

Technical Field

[0001] This invention relates to the field of tunnel construction technology, and in particular to a method for stopping water in the drilling of grouting holes for tunnel curtain grouting. Background Technology

[0002] In tunnel construction traversing debris flow deposits, curtain grouting is a crucial step in reinforcing loose strata and blocking groundwater seepage. During construction, a concrete grout-stopping wall must first be constructed at the tunnel face, followed by drilling grouting holes for reinforcement. However, debris flow deposits are characterized by their loose structure, high porosity, and high water content, making them highly susceptible to penetrating aquifers or fracture zones during drilling, potentially leading to high-pressure water inrush or even sudden water surges. Currently, conventional drilling methods for sealing rely on installing expansion rubber plugs at the grouting hole openings or expansion bags on the drill rods, using their mechanical expansion force to seal the borehole wall. While this method is effective in general low-permeability environments, the low rock strength of debris flow deposits and high water inrush volumes can cause high-pressure water to leak along the periphery of the plug or directly damage the fragile borehole wall after prolonged pressure, leading to seal failure. Therefore, there is an urgent need to improve existing sealing measures to suit the high-pressure water inrush environment of debris flow deposits. Summary of the Invention

[0003] The purpose of this invention is to overcome the technical problem that existing water-stopping measures are prone to leakage or direct damage to the fragile hole walls in the high-pressure water inflow environment of debris flow deposits, leading to sealing failure, and to provide a water-stopping method for drilling grouting holes for tunnel curtain grouting.

[0004] This invention provides a method for sealing water in grouting holes for tunnel curtain grouting. The method employs a water-sealing device inserted into the grouting hole. The water-sealing device includes a drill rod, a drill bit, and an expansion bag. The drill bit is installed at one end of the drill rod and communicates with it. The expansion bag is fitted onto the drill rod. The water-sealing method includes:

[0005] S1: After water flows into the grouting hole, the drilling of the drill bit is paused, and the drill rod stops rotating;

[0006] S2: Pressurize the expansion bladder to a first preset pressure, causing the expansion bladder to expand and adhere tightly to the inner wall of the injection hole;

[0007] S3: Grout is injected into the drill rod, so that the grout enters the annular space between the drill rod and the inner wall of the grouting hole from the drill bit; after the pressure of the grout reaches the first preset pressure, grouting is paused and the pressure is stabilized;

[0008] S4: Reduce the pressure of the inflatable bladder to the second preset pressure;

[0009] S5: Continue grouting at the first preset pressure until only the grout flows out of the grouting hole.

[0010] S6: Apply secondary pressure to the expansion bladder until there is no water seepage and no grout flow at the opening of the grouting hole, and at the same time stop grouting and stabilize the pressure.

[0011] This invention improves upon existing methods that rely on mechanical expansion for water sealing. By injecting grout into the drill rod, it can counteract high-pressure, high-flow-rate water inrush. The water sealing operation requires a combination of grouting and expansion. Specifically, when water inrush occurs, drilling is first stopped, meaning the drill rod and drill bit stop rotating, and the circulation of the drilling fluid in the drill rod is halted. After the water inrush has largely drained the remaining drilling fluid from the grouting hole, pressure is applied to the expansion bladder to expand it and seal the grouting hole as a preliminary sealing measure. At this point, the water inrush is initially blocked on the side of the expansion bladder facing the drill bit. Grout is then injected into the drill rod. The grout enters the grouting hole through the drill bit and mixes with the water inrush blocked on the expansion bladder side. As the grout is continuously injected, the grouting pressure gradually increases. When the grouting pressure equals the pressure in the expansion bladder, the pressure resistance limit of the expansion bladder has been reached. At this point, grouting is paused, and the grout pressure is stabilized. Then, the internal pressure of the expansion bladder is actively reduced. When the grout pressure exceeds the internal pressure of the expansion bladder, the mixture of grout and gushing water can force open the expansion bladder and overflow from between the expansion bladder and the borehole wall. Continuing grouting at this point can increase the concentration of grout in the grouting hole. When only pure grout is observed flowing out at the grouting hole opening, it means that the gushing water in the grouting hole has been basically drained. Then, pressurize the expansion bladder to seal the grouting hole and stop grouting. If there is no water seepage and no grout flows out of the grouting hole, it is necessary to continue stabilizing the pressure for a period of time. After the grout in the grouting hole solidifies, the pressure in the expansion bladder can be released. Subsequently, water can be stopped solely by relying on the solidified grout in the grouting hole. The grout can stabilize the borehole wall to prevent borehole collapse and can also seep into the cracks in the rock strata to reinforce the rock strata and prevent water seepage. This is equivalent to implementing a small-scale curtain grouting as a temporary protection during the drilling process using the drill rod. By replacing the existing sealing measures that rely solely on mechanical expansion with the solidified grout in the grouting hole, it is possible to effectively cope with the high-pressure water inflow environment and achieve good water-stopping effect.

[0012] Preferably, a pressurization channel is provided in the side wall of the drill pipe, and the pressurization channel is in communication with the expansion bladder.

[0013] By setting the pressurization channel connected to the expansion bladder in the side wall of the drill pipe, the expansion bladder can serve as a primary water-stopping measure. A secondary water-stopping measure can be set at the location of the pressurization channel on the drill pipe (i.e., upstream of the grouting direction inside the drill pipe) to enhance the water-stopping effect.

[0014] Preferably, the water-stopping device further includes an expansion sealing element, which is sleeved on the drill rod and located upstream of the expansion bladder in the grouting direction of the drill rod; in S6, if water seeps out or grout flows out at the opening of the grouting hole after the expansion bladder is pressurized to the maximum pressure for the second time, the expansion sealing element is brought into contact with water, causing the expansion sealing element to expand and adhere tightly to the inner wall of the grouting hole.

[0015] An expansion sealing element can be installed upstream of the grouting direction inside the drill pipe (i.e., at the location of the pressurization channel on the drill pipe) as a secondary water-stopping measure. When the expansion bag, which serves as the primary water-stopping measure, still leaks after being pressurized to the maximum pressure and cannot achieve sealing, the expansion sealing element can be made to expand upon contact with water to achieve secondary sealing.

[0016] Preferably, the outer surface of the expansion seal is covered with a waterproof membrane, and the method for bringing the expansion seal into contact with water includes: removing the waterproof membrane.

[0017] Under normal circumstances, the expansion seal is covered with a waterproof membrane to isolate it from water, so as to prevent it from expanding when it is not needed and affecting the drilling operation of the drill pipe. When it is necessary to activate the secondary water-stopping measures, the waterproof membrane on the surface of the expansion seal can be removed first, and then the expansion seal can be exposed to water to expand and achieve the seal.

[0018] Preferably, the waterproof membrane is attached with a sealing strip, and the method for removing the waterproof membrane includes:

[0019] C1: Pinch the opening strip;

[0020] C2: Remove the opening strip and the waterproof membrane together.

[0021] Specifically, the waterproof membrane can be removed by using the opening strip set on it. When the expansion seal is located at the opening of the grouting hole, the waterproof membrane can be removed by manually pinching the opening strip and tearing it off. When the expansion seal is located inside the grouting hole and it is impossible to put your hand into the grouting hole to operate, a special mechanical tool can be used to reach into the grouting hole and tear off the waterproof membrane.

[0022] Preferably, two axial limiting rings are provided on the outer wall of the drill pipe at axial intervals, and the expansion sealing member is disposed between the two axial limiting rings, with both axial limiting rings abutting against the expansion sealing member.

[0023] To ensure the sealing effect of the expansion sealing component and to ensure that its expansion direction is mainly along the radial direction of the grouting hole, axial limiting rings can be set on both sides of the expansion sealing component to prevent the expansion sealing component from expanding axially.

[0024] Preferably, the waterproof membrane is connected between the two axial limiting rings.

[0025] A waterproof membrane can be connected between two axial limiting rings to cover and seal the expansion sealing component. The axial sides of the expansion sealing component can be waterproofed through the axial limiting rings, and the circumferential surface of the expansion sealing component can be waterproofed through the waterproof membrane.

[0026] Preferably, the drill pipe is fitted with a pressure bag that communicates with the pressure channel, and the pressure channel is connected between the pressure bag and the expansion bag.

[0027] One end of the pressurization channel can be connected to an expansion bladder, and the other end can be connected to a pressure bladder. Both the expansion bladder and the pressure bladder can be made of elastic material. When the pressure bladder is not filled with medium, it can be a flexible structure that can rotate with the drill rod and enter the grouting hole during drilling operations. During manufacturing, a pressure bladder with a sufficient length can be selected to ensure that the inlet end of the pressure bladder is outside the grouting hole after the drill rod is inserted into it. This facilitates connecting the inlet end of the pressure bladder to the pressurization pipe and pressurization equipment for pressurization operations.

[0028] Preferably, the second preset pressure is 70% to 80% of the first preset pressure.

[0029] In step S3 above, after the first grouting and pressurization to the first preset pressure, the space between the drill bit and the expansion bag is still filled with groundwater. The injected grout will mix with the groundwater, thus diluting the grout and reducing the sealing and water-stopping effect. Therefore, in step S4 above, the pressure in the expansion bag needs to be reduced to the second preset pressure, that is, slightly reduced, so that the expansion bag is just unable to seal the grouting pressure. This allows the mixture of grout and groundwater in the space between the drill bit and the expansion bag to seep from between the expansion bag and the inner wall of the grouting hole. After the seepage begins, in step S5 above, the pressure is maintained at the second preset pressure. The first preset pressure grouting is performed when only grout flows out of the grouting hole, which means that the groundwater in the space between the drill bit and the expansion bag has been basically drained. In other words, the space between the drill bit and the expansion bag is basically filled with grout. Then, step S6 is performed again, which means that the pressure in the expansion bag is increased again until complete sealing is achieved. After the grout in the space between the drill bit and the expansion bag solidifies, the water stoppage of the grouting hole can be achieved. The second preset pressure in the expansion bag can be selected as 70% to 80% of the first preset pressure, or other proportions can be selected as needed.

[0030] Preferably, the slurry material includes a two-component slurry or polyurethane, and the medium filled in the expansion bladder includes water or air.

[0031] To achieve better water-stopping effect, the grout material can be a two-component grout or polyurethane, and the pressurizing medium in the expansion bladder can be water or air.

[0032] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0033] This invention provides a method for sealing water in grouting holes for tunnel curtain grouting. This method improves upon existing mechanical expansion-based sealing techniques by using grouting through the drill rod to combat high-pressure, high-flow-rate water inrush. The sealing operation combines grouting and expansion. Specifically, when water inrush occurs, drilling is first stopped—the drill rod and drill bit stop rotating, and the circulation of the drilling fluid in the drill rod is halted. After the water inrush has largely drained the remaining drilling fluid from the grouting hole, pressure is applied to the expansion bladder to expand it and seal the grouting hole as a preliminary sealing measure. At this point, the water inrush is initially sealed on the side of the expansion bladder facing the drill bit. Grout is then injected into the drill rod, entering the grouting hole through the drill bit and mixing with the water sealed on the expansion bladder side. As grout is continuously injected, the grouting pressure gradually increases. When the grouting pressure equals the pressure in the expansion bladder, the pressure resistance limit of the expansion bladder has been reached. At this point, grouting is paused, and the grout pressure is stabilized. Then, actively reduce the internal pressure of the expansion bladder. Since the grout pressure is greater than the internal pressure of the expansion bladder, the mixture of grout and gushing water can force open the expansion bladder and overflow from between the expansion bladder and the borehole wall. At this time, continuing grouting can increase the concentration of grout in the grouting hole. When only pure grout is observed flowing out at the grouting hole opening, it means that the gushing water in the grouting hole has been basically drained. Then, repressurize the expansion bladder to seal the grouting hole and stop grouting. If there is no water seepage and no grout flows out of the grouting hole, it is necessary to continue to stabilize the pressure for a period of time. Once the grout in the injection hole solidifies, it can depressurize the expansion bladder. Subsequently, water can be stopped solely by the solidified grout in the injection hole. The grout can stabilize the hole wall to prevent collapse and can also seep into the cracks in the rock strata to reinforce the rock strata and prevent water inrush. This is equivalent to implementing a small-scale curtain grouting as a temporary protection during the drilling process using the drill rod. By replacing the existing sealing measures that rely solely on mechanical expansion with the solidified grout in the injection hole, it can effectively cope with high-pressure water inrush environment and has a good water-stopping effect. Attached Figure Description

[0034] Figure 1 A schematic diagram of the water-stopping device used in the water-stopping method of the present invention (the expansion bladder and expansion sealing element are not expanded).

[0035] Figure 2 A schematic diagram of the water-stopping device used in the water-stopping method of the present invention (both the expansion bladder and the expansion sealing component have been expanded).

[0036] Figure 3 for Figure 2 Cross-sectional view at "AA" in the middle.

[0037] Figure 4 This is a partial perspective view of the water-stopping device used in the water-stopping method of the present invention.

[0038] Marked in the image:

[0039] 1. Drill rod; 11. Pressurization channel; 2. Drill bit; 3. Expansion bladder; 4. Expansion sealing component; 5. Waterproof membrane; 51. Opening strip; 6. Axial limiting ring; 7. Pressurization bladder; 8. Pressurization pipe; 9. Grouting hole. Detailed Implementation

[0040] The present invention will now be described in further detail with reference to specific embodiments. However, this should not be construed as limiting the scope of the present invention to the following embodiments; all technologies implemented based on the content of the present invention fall within the scope of the present invention.

[0041] Unless otherwise specified, the use of terms such as "upper," "lower," "left," "right," "center," "inner," and "outer" to indicate orientation or positional relationships in the description of specific embodiments of the present invention is based on the orientation or positional relationships shown in the accompanying drawings, or the orientation or positional relationship in which the product / equipment / device is typically placed during use. These terms are merely for the purpose of facilitating the description of the present invention or simplifying the description in specific embodiments, enabling those skilled in the art to quickly understand the solution, and do not indicate or imply that a particular device / component / element must have a specific orientation, or be constructed and operated in a specific positional relationship. Therefore, they should not be construed as limitations on the present invention.

[0042] Furthermore, the use of terms such as "horizontal," "vertical," "suspended," and "parallel" does not imply that the corresponding device / component / element must be absolutely horizontal, vertical, suspended, or parallel, but rather that it can be slightly tilted or have a deviation. For example, "horizontal" merely means that its direction is more horizontal relative to "vertical," not that the structure must be completely horizontal, but that it can be slightly tilted. Alternatively, it can be simplified to mean that the corresponding device / component / element, when set in a "horizontal," "vertical," "suspended," or "parallel" direction, can have an error / deviation of ±10% relative to the corresponding direction, more preferably within ±8%, more preferably within ±6%, more preferably within ±5%, and more preferably within ±4%. As long as the corresponding device / component / element is within the error / deviation range, it can still achieve its function in the present invention.

[0043] Furthermore, the use of terms such as "first," "second," and "third" in terminology is merely for distinguishing descriptions of identical or similar components and should not be interpreted as emphasizing or implying the relative importance of a particular component.

[0044] Furthermore, in the description of the embodiments of the present invention, "several", "more than", and "a number of" represent at least two. The number can be any number, such as 2, 3, 4, 5, 6, 7, 8, or 9, and can even exceed nine.

[0045] Furthermore, in the description of the technical solution of this invention, unless otherwise explicitly specified / limited / restricted, the terms "set up," "install," "connect," "link," "provided with," "laid out," and "arranged" should be interpreted broadly. For example, they can refer to fixed connections, detachable connections, or integral connections; they can refer to common connection methods in the art, such as welding, riveting, bolting, and threaded connections. Such connections can be mechanical, electrical, or communication connections; they can be direct connections or indirect connections through an intermediate medium; and they can refer to the internal communication between two components.

[0046] Example

[0047] This embodiment provides a water-stopping method for drilling grouting holes for tunnel curtain grouting.

[0048] Figure 1 A schematic diagram of the water-stopping device used in the water-stopping method of the present invention (neither the expansion bladder nor the expansion sealing component is expanded). Figure 2 A schematic diagram of the structure of the water-stopping device used in the water-stopping method of the present invention (both the expansion bladder and the expansion sealing component have been expanded). Figure 3 for Figure 2 Cross-sectional view at point "AA" in the middle; Figure 4 This is a partial perspective view of the water-stopping device used in the water-stopping method of the present invention.

[0049] like Figures 1 to 4 As shown in the figure, the water-stopping method for the grouting hole drilled for tunnel curtain grouting in this embodiment can adopt a water-stopping device inserted into the grouting hole 9. The water-stopping device includes a drill rod 1, a drill bit 2, and an expansion bag 3. The drill bit 2 is installed at one end of the drill rod 1 and communicates with the drill rod 1. The expansion bag 3 is sleeved on the drill rod 1. The water-stopping method includes:

[0050] S1: After water flows into the grouting hole 9, stop drilling the drill bit 2 and stop the drill rod 1 from rotating;

[0051] S2: Pressurize the expansion bladder 3 to the first preset pressure, so that the expansion bladder 3 expands and adheres tightly to the inner wall of the grouting hole 9;

[0052] S3: Inject grout into drill rod 1, so that the grout enters the annular space between drill rod 1 and the inner wall of grouting hole 9 from drill bit 2; after the pressure of the grout reaches the first preset pressure, stop grouting and stabilize the pressure;

[0053] S4: Reduce the pressure of the inflatable bladder 3 to the second preset pressure;

[0054] S5: Continue grouting at the first preset pressure until only grout flows out of the opening of grouting hole 9;

[0055] S6: Apply secondary pressure to the expansion bladder 3 until there is no water seepage and no grout flow at the opening of the grouting hole 9, and at the same time stop grouting and stabilize the pressure.

[0056] The water-stopping method of this invention improves upon existing methods that rely on mechanical expansion. By injecting grout into the drill rod 1, it can counteract high-pressure, high-flow-rate water inrush. The water-stopping operation requires a combination of grouting and expansion. Specifically, when water inrush occurs, drilling is first stopped, meaning the drill rod 1 and drill bit 2 stop rotating, and the circulation of the drilling fluid in the drill rod 1 is halted. After the water inrush has essentially drained the remaining drilling fluid from the grouting hole 9, pressure is applied to the expansion bag 3 to expand it and seal the grouting hole 9 as a preliminary sealing measure. At this point, the water inrush is initially blocked on the side of the expansion bag 3 facing the drill bit 2. Grout is then injected into the drill rod 1. The grout enters the grouting hole 9 through the drill bit 2 and mixes with the water inrush blocked on one side of the expansion bag 3. As the grout is continuously injected, the grouting pressure gradually increases. When the grouting pressure is the same as the pressure in the expansion bag 3, the pressure resistance limit of the expansion bag 3 has been reached. At this point, grouting is paused, and the grout pressure is stabilized. Then, the internal pressure of the expansion bag 3 is actively reduced. Because the grout pressure is greater than the internal pressure of the expansion bag 3, the mixture of grout and gushing water can force open the expansion bag 3 and overflow from between the expansion bag 3 and the hole wall. At this time, continuing grouting can increase the concentration of grout in the grouting hole 9. When only pure grout is observed flowing out at the opening of the grouting hole 9, it means that the gushing water in the grouting hole 9 has been basically drained. Then, pressurize the expansion bag 3 again to seal the grouting hole 9 and stop grouting. If there is no water seepage and no grout flows out of the grouting hole 9, it is necessary to continue to stabilize the pressure for a period of time. After the grout in grouting hole 9 solidifies, it can depressurize the expansion bag 3. Subsequently, water can be stopped by relying solely on the solidified grout in grouting hole 9. The grout can stabilize the hole wall to prevent hole collapse and can also seep into the cracks of the rock strata to reinforce the rock strata and prevent water inrush. This is equivalent to implementing a small-scale curtain grouting as a temporary protection during the drilling process using drill rod 1. By replacing the existing sealing measures that rely solely on mechanical expansion with the solidified grout in grouting hole 9, the high-pressure water inrush environment can be effectively dealt with, and the water-stopping effect is good.

[0057] It should be noted that when grouting is performed in the center hole of drill rod 1, the grout can flow out from the overflow hole (not shown in the figure) on drill bit 2. Part of the grout first enters the surrounding rock fissures of the grouting hole 9, and may enter the annular space outside the drill rod 1 between the expansion bag 3 and drill bit 2 along the surrounding rock fissures as the grouting pressure increases. Another part of the grout can directly enter the annular space outside the drill rod 1 between the expansion bag 3 and drill bit 2 through the gap between the outer surface of drill bit 2 and the wall of grouting hole 9 (because the outer surface of drill bit 2 has cutting teeth of rock mass, the outer surface of drill bit 2 is not a smooth surface, so a gap will be left between drill bit 2 and hole wall. This gap is not directly shown in the figure, but it actually exists).

[0058] Figure 1 , Figure 2 and Figure 4 The direction of arrow B is the direction of pressurization that causes the expansion bladder 3 to expand, and the direction of arrow C is the direction of grouting inside the drill pipe 1.

[0059] In this embodiment, a pressurization channel 11 is provided in the side wall of the drill rod 1, and the pressurization channel 11 is connected to the expansion bag 3. By setting the pressurization channel 11 connected to the expansion bag 3 in the side wall of the drill rod 1, the expansion bag 3 can be used as a primary water-stopping measure, and a secondary water-stopping measure can be set at the location of the pressurization channel 11 on the drill rod 1 (i.e., upstream of the grouting direction inside the drill rod 1) to enhance the water-stopping effect.

[0060] In this embodiment, the water-stopping device also includes an expansion sealing component 4, which is sleeved on the drill rod 1 and located upstream of the expansion bag 3 in the grouting direction of the drill rod 1. In S6, if water seepage or grout flow occurs at the opening of the grouting hole 9 after the expansion bag 3 is pressurized to the maximum pressure for the second time, the expansion sealing component 4 is brought into contact with water, causing it to expand and adhere tightly to the inner wall of the grouting hole 9. Specifically, the expansion sealing component 4 can be set as a secondary water-stopping measure upstream of the grouting direction in the drill rod 1 (i.e., at the location of the pressurization channel 11 on the drill rod 1). When the expansion bag 3, which serves as the primary water-stopping measure, still leaks after being pressurized to the maximum pressure and cannot be sealed, the expansion sealing component 4 can be made to expand upon contact with water to achieve secondary sealing.

[0061] In this embodiment, the outer surface of the expansion sealing component 4 is covered with a waterproof membrane 5. The method of making the expansion sealing component 4 come into contact with water includes: removing the waterproof membrane 5. Under normal circumstances, the expansion sealing component 4 is isolated from water by covering it with a waterproof membrane 5 to prevent it from expanding when it is not needed and affecting the drilling operation of the drill rod 1. When it is necessary to activate the secondary water-stopping measures, the waterproof membrane 5 on the surface of the expansion sealing component 4 can be removed first, and then the expansion sealing component 4 can be brought into contact with water to expand and achieve sealing.

[0062] Alternatively, a sealing strip 51 is attached to the waterproof membrane 5, and the method for removing the waterproof membrane 5 includes the following steps:

[0063] C1: Pinch the opening strip 51;

[0064] C2: Remove the opening strip 51 and the waterproof membrane 5 together.

[0065] Specifically, the waterproof membrane 5 is similar to product packaging film. When unopened, it provides waterproofing to the internal expansion seal 4, preventing the expansion seal 4 from expanding when not needed. If the expansion seal 4 needs to expand for sealing, it can be removed using the opening strip 51 on the waterproof membrane 5. When the expansion seal 4 is located at the opening of the grouting hole 9, it can be removed by manually pinching the opening strip 51 and tearing off the waterproof membrane 5. When the expansion seal 4 is inside the grouting hole 9 and cannot be opened, it can be removed by manually pinching the opening strip 51 and tearing off the waterproof membrane 5. When operating with your hand inside the grouting hole 9, you can use a special mechanical tool to tear off the waterproof membrane 5 inside the grouting hole 9. Here, the opening strip 51 can be designed as an integral structure with the waterproof membrane 5. An indentation line can be set at the joint between the opening strip 51 and the waterproof membrane 5. When removing the waterproof membrane 5, you can pinch the opening strip 51 with your hand or clamp the opening strip 51 with a tool and then apply a pulling force. The waterproof membrane 5 can be broken along the indentation line between the opening strip 51 and the waterproof membrane 5, so that the waterproof membrane 5 can be completely removed from the surface of the expansion sealing component 4, thereby achieving the removal of the waterproof membrane 5.

[0066] In this embodiment, two axial limiting rings 6 are provided on the outer wall of the drill rod 1 at axial intervals, and the expansion sealing member 4 is disposed between the two axial limiting rings 6. Both axial limiting rings 6 abut against the expansion sealing member 4. In order to ensure the sealing effect of the expansion sealing member 4 and ensure that its expansion direction is mainly along the radial direction of the grouting hole 9, axial limiting rings 6 can be provided on both sides of the expansion sealing member 4 to prevent the expansion sealing member 4 from expanding axially.

[0067] Optionally, the waterproof membrane 5 is connected between two axial limiting rings 6; the waterproof membrane 5 can be connected between two axial limiting rings 6 to cover and seal the expansion sealing member 4, the axial sides of the expansion sealing member 4 can be waterproofed by the axial limiting rings 6, and the circumferential surface of the expansion sealing member 4 can be waterproofed by the waterproof membrane 5.

[0068] In this embodiment, a pressure bag 7 connected to a pressure channel 11 is fitted on the drill rod 1. The pressure channel 11 connects the pressure bag 7 and the expansion bag 3. One end of the pressure channel 11 can be connected to the expansion bag 3, and the other end of the pressure channel 11 can be connected to the pressure bag 7. Both the expansion bag 3 and the pressure bag 7 can be made of elastic material (e.g., rubber). The pressure bag 7 is a flexible structure when it is not filled with medium. It can rotate with the drill rod 1 and enter the grouting hole 9 when the drill rod 1 is drilling. The pressure bag 7 with a sufficient length can be selected during manufacturing. This can ensure that the inlet end of the pressure bag 7 is outside the grouting hole 9 after the drill rod 1 is inserted into the grouting hole 9. This makes it easy to connect the inlet end of the pressure bag 7 to the pressure pipe 8 and the pressure equipment for pressure operation.

[0069] Specifically, the materials of the expansion bag 3 and the pressure bag 7 can be selected as elastic rubber materials, etc.; both the expansion bag 3 and the pressure bag 7 can be sleeved and wrapped around the drill rod 1, and the expansion bag 3 and the pressure bag 7 are respectively located at both ends of the pressure channel 11 and connected to the pressure channel 11; the connection between the expansion bag 3 and the pressure bag 7 and the drill rod 1 can be sealed by vulcanized rubber to ensure the sealing between the expansion bag 3 and the drill rod 1 and between the pressure bag 7 and the drill rod 1.

[0070] Alternatively, the material of the expansion sealing component 4 may include expansion rubber; specifically, the expansion rubber may be the rubber material of BW type or PN type rubber waterstop strip, or it may be a solid sealing material that can expand rapidly when exposed to water, such as water-based polyurethane prepolymer particles, fast-setting polyurethane or high swelling degree waterproof blanket (GCL). Compared with the expansion rate of expansion rubber, which is relatively slow, the above-mentioned fast-expanding solid sealing material can quickly achieve the sealing of the grouting hole 9.

[0071] Optionally, there may be multiple pressurization channels 11, which are arranged circumferentially along the side wall of the drill rod 1 and parallel to the central hole (i.e., grouting channel) of the drill rod 1. Here, the figure shows 6 pressurization channels 11, which are evenly distributed in the side wall of the drill rod 1 and arranged circumferentially outside the central hole of the drill rod 1. Of course, the number of pressurization channels 11 is not limited to 6, and other numbers may be selected as needed. The present invention does not make a specific limitation in this regard.

[0072] Optionally, the second preset pressure is 70% to 80% of the first preset pressure. In step S3 above, after the first grouting and pressurization to the first preset pressure, the space between the drill bit 2 and the expansion bag 3 is still filled with groundwater. The injected grout will mix with the groundwater, thereby diluting the grout and reducing the sealing and water-stopping effect. Therefore, in step S4 above, the pressure in the expansion bag 3 needs to be reduced to the second preset pressure, that is, slightly reduced, so that the expansion bag 3 is just unable to seal the grouting pressure. This allows the mixture of grout and groundwater in the space between the drill bit 2 and the expansion bag 3 to seep from between the expansion bag 3 and the inner wall of the grouting hole 9. After the seepage begins... In step S5 above, grouting continues at the first preset pressure. When only grout flows out of the grouting hole 9, it means that the groundwater in the space between the drill bit 2 and the expansion bag 3 has been basically drained. In other words, the space between the drill bit 2 and the expansion bag 3 is basically filled with grout. Then, step S6 above is executed again, which means that the pressure in the expansion bag 3 is increased again until complete sealing is achieved. After the grout in the space between the drill bit 2 and the expansion bag 3 solidifies, the water stoppage of the grouting hole 9 can be achieved. The second preset pressure in the expansion bag 3 can be selected as 70% to 80% of the first preset pressure, or other proportions can be selected as needed.

[0073] Alternatively, the slurry material may include a two-component slurry or polyurethane, and the medium filling the expansion bladder 3 may include water or air.

[0074] To achieve a better water-stopping effect, the grout material can be a two-component grout or polyurethane, and the pressurizing medium in the expansion bladder 3 can be water or air.

[0075] In summary, this invention provides a method for sealing water in grouting holes for tunnel curtain grouting. This method improves upon existing mechanical expansion methods by using grouting via the drill rod to counteract high-pressure, high-flow-rate water inrush. The sealing operation requires a combination of grouting and expansion. Specifically, when water inrush occurs, drilling is first stopped, meaning the drill rod and drill bit stop rotating, and the circulation of the drilling fluid in the drill rod is halted. After the water inrush has largely drained the remaining drilling fluid from the grouting hole, pressure is applied to the expansion bladder to expand it and seal the grouting hole as a preliminary sealing measure. At this point, the water inrush is initially sealed on the side of the expansion bladder facing the drill bit. Grout is then injected into the drill rod, and the grout enters the grouting hole through the drill bit, mixing with the water sealed on the expansion bladder side. As the grout is continuously injected, the grouting pressure gradually increases. When the grouting pressure equals the pressure in the expansion bladder, the pressure resistance limit of the expansion bladder has been reached. At this point, grouting is paused, and the grout pressure is kept stable. Once the pressure is stable, actively reduce the internal pressure of the expansion bladder. Because the grout pressure is greater than the internal pressure of the expansion bladder, the mixture of grout and gushing water can force open the expansion bladder and overflow from between the expansion bladder and the borehole wall. At this time, continuing grouting can increase the concentration of grout in the grouting hole. When only pure grout is observed flowing out at the grouting hole opening, it means that the gushing water in the grouting hole has been basically drained. Then, repressurize the expansion bladder to seal the grouting hole and stop grouting. If there is no water seepage and no grout flows out of the grouting hole, continue to stabilize the pressure for a period of time. During this process, once the grout in the injection hole solidifies, it can depressurize the expansion bladder. Subsequently, water can be stopped solely by the solidified grout in the injection hole. The grout can stabilize the borehole wall to prevent collapse and can also seep into the cracks in the rock strata to reinforce the rock strata and prevent water inrush. This is equivalent to implementing a small-scale curtain grouting as a temporary protection during the drilling process using the drill rod. By replacing the existing sealing measures that rely solely on mechanical expansion with the solidified grout in the injection hole, it can effectively cope with high-pressure water inrush environments and achieve good water-stopping effects.

[0076] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A method for sealing a drill hole for tunnel curtain grouting, using a sealing device arranged in a grouting hole (9), the sealing device comprising a drill rod (1), a drill bit (2) and an inflatable bladder (3), the drill bit (2) being mounted at one end of the drill rod (1) and communicating with the drill rod (1), the inflatable bladder (3) being sleeved on the drill rod (1); characterized in that, The water-stopping method includes: S1: After water flows into the grouting hole (9), the drilling of the drill bit (2) is paused, and the drill rod (1) stops rotating; S2: Pressurize the expansion bladder (3) to a first preset pressure, so that the expansion bladder (3) expands and adheres tightly to the inner wall of the grouting hole (9); S3: Grout is injected into the drill rod (1) so that the grout enters the annular space between the drill rod (1) and the inner wall of the grouting hole (9) from the drill bit (2); after the pressure of the grout reaches the first preset pressure, the grouting is stopped and the pressure is stabilized; S4: Reduce the pressure of the inflatable bladder (3) to the second preset pressure; S5: Continue grouting at the first preset pressure until only the grout flows out of the opening of the grouting hole (9); S6: Apply pressure to the expansion bladder (3) a second time until there is no water seepage and no grout flows out at the opening of the grouting hole (9), and at the same time stop grouting and stabilize the pressure; A pressurization channel (11) is provided in the side wall of the drill rod (1), and the pressurization channel (11) is connected to the expansion bladder (3); The water-stopping device also includes an expansion sealing element (4), which is sleeved on the drill rod (1) and located upstream of the expansion bag (3) in the grouting direction of the drill rod (1); in S6, if water seeps out or grout flows out at the opening of the grouting hole (9) after the expansion bag (3) is pressurized to the maximum pressure for the second time, the expansion sealing element (4) is brought into contact with water, causing the expansion sealing element (4) to expand and stick tightly to the inner wall of the grouting hole (9); The outer surface of the expansion sealing member (4) is covered with a waterproof membrane (5), and the method of bringing the expansion sealing member (4) into contact with water includes: removing the waterproof membrane (5); Two axial limiting rings (6) are provided on the outer wall of the drill rod (1) at axial intervals. The expansion sealing member (4) is disposed between the two axial limiting rings (6), and both axial limiting rings (6) abut against the expansion sealing member (4). The waterproof membrane (5) is connected between the two axial limiting rings (6). A pressure bag (7) communicating with the pressure channel (11) is sleeved on the drill rod (1). The pressure channel (11) is connected between the pressure bag (7) and the expansion bag (3).

2. The water-stopping method for drilling grouting holes for tunnel curtain grouting according to claim 1, characterized in that, The waterproof membrane (5) is connected to a sealing strip (51), and the method for removing the waterproof membrane (5) includes: C1: Pinch the opening strip (51); C2: Remove the opening strip (51) and the waterproof membrane (5) together.

3. The water-stopping method for drilling grouting holes for tunnel curtain grouting according to claim 1 or 2, characterized in that, The second preset pressure is 70% to 80% of the first preset pressure.

4. The water-stopping method for drilling grouting holes for tunnel curtain grouting according to claim 1 or 2, characterized in that, The slurry material includes a two-component slurry or polyurethane, and the medium filled in the expansion bladder (3) includes water or air.

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