A composite polymer grouting method for underground engineering rock cave
By using a composite polymer grouting method, a dual-structure seepage prevention system is formed by injecting a combination of foamed and permeable polymers. This solves the problems of incomplete sealing and low construction efficiency in traditional grouting methods, and improves the safety and service life of underground engineering projects.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- CCCC FIRST HIGHWAY CONSULTANTS CO LTD
- Filing Date
- 2025-07-25
- Publication Date
- 2026-07-21
AI Technical Summary
Traditional grouting methods cannot simultaneously seal and reinforce rock fissures and effectively fill karst caves, resulting in poor treatment effects, low construction efficiency, and high costs.
A composite polymer grouting method is adopted, using four grouting pipes (sealing grouting pipe, cave grouting pipe, first crack grouting pipe, and second crack grouting pipe) to drill holes in one go. First, foamed polymer is injected to fill the cave, and then penetrating polymer is injected to fill the crack, forming a dual structure of "crack seepage prevention + cave sealing".
It enables precise grouting of karst caves and surrounding cracks, reduces the amount of drilling, lowers the cost of water leakage control, and improves the safety and service life of underground engineering projects.
Smart Images
Figure CN120626216B_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of underground engineering management technology, and in particular to a composite polymer grouting method for underground rock caverns. Background Technology
[0002] With the acceleration of urbanization and the deepening of underground space development, the geological conditions faced by deep underground engineering projects are becoming increasingly complex. In the construction and operation of underground engineering projects such as national defense, civil defense, tunnels, and caverns, karst caves, formed in karst landforms, are a common adverse geological phenomenon, widely distributed in the rock strata surrounding various underground projects. When encountering rainy weather or abundant groundwater, hidden caves in the outer rock mass of the initial support can easily become channels for groundwater accumulation, seeping into the cavern interior through rock fissures. Long-term seepage can lead to pressure damage to the lining, seriously affecting the safety and normal function of the underground project.
[0003] Grouting is a commonly used method for addressing water seepage from rock cavities and fissures in underground engineering projects. Currently, common grouting methods include traditional cement grouting and single-organic-material grouting. Traditional cement grouting involves drilling holes to inject cement grout into rock fissures and cavities, relying on the grout's hardening to seal the seepage channels. However, cement grout particles are relatively large, making it difficult to effectively penetrate micro-cracks. Furthermore, its long setting time and tendency to shrink after solidification make it highly susceptible to groundwater flow, resulting in poor grouting effectiveness.
[0004] Another approach involves a two-stage grouting method using organic polyurethane grout. First, a low-viscosity grout is injected to seal the cracks, followed by a foamed grout to fill the cavities. This method requires drilling two sets of holes, resulting in low construction efficiency and increasing costs by more than 50%.
[0005] In summary, traditional cement-based grouts have large particle sizes and poor diffusivity, making it impossible to balance permeability and expansion, resulting in incomplete crack sealing. Single polymer grouting methods, due to their limited material functionality, cannot simultaneously reinforce and seal rock fissures and fill and seal rock cavities. Existing segmented grouting methods require multiple drilling and repeated construction, disturbing the rock mass and extending the construction period. Traditional inorganic materials have high shrinkage rates and poor long-term seepage prevention effects. Summary of the Invention
[0006] The purpose of this invention is to overcome the shortcomings of traditional grouting methods, which are difficult to simultaneously seal and reinforce rock fissures and effectively fill karst caves, have poor treatment effects on karst caves with complex fissure networks, and are inefficient and costly. This invention provides a composite polymer grouting method for underground rock karst caves.
[0007] In a first aspect, the present invention provides a composite polymer grouting method for underground rock caverns, comprising the following steps: S1: Detect the location of water seepage in underground engineering projects, determine the location and extent of karst caves, and the development of surrounding cracks; S2: Drill grouting holes at the circumferential section of the seepage location, and arrange sealing grouting pipes, karst cave grouting pipes, first crack grouting pipes and second crack grouting pipes in the grouting holes, and install grouting caps; The length of the second crack grouting pipe is 70cm to 120cm longer than the length of the first crack grouting pipe. Grouting pipes for karst caves are used to inject grout into karst caves, while grouting pipes for first and second fissures are used to inject grout into fissures. S3: Sealing Grouting: First, use the sealing grouting pipe to grout and seal the hole; Then, foamed polymer is injected through the grouting pipe to form a foamed polymer grouting ring on the entire cross-section near the karst cave seepage point. Then, first inject the penetrating polymer through the second crack grouting pipe, and then inject the penetrating polymer through the first crack grouting pipe to form a penetrating polymer grouting ring on the entire cross section where water seepage occurs at the far end of the crack. S4: Test the effectiveness of the seepage control and complete the construction.
[0008] The composite polymer grouting method for underground rock caverns provided by this invention arranges four grouting pipes (sealing grouting pipe, cave grouting pipe, first crack grouting pipe, and second crack grouting pipe) in each grouting hole. Precise grouting of the cavern and surrounding cracks at different depths can be completed in one drilling, without the need for repeated drilling, reducing secondary disturbance to the rock mass, reducing the amount of drilling, and lowering the cost of seepage control. Grouting holes are drilled in the circumferential section (i.e., the entire cross-section) at the seepage location: Foamed polymers can enter the karst cave along the grouting pipe. The foamed polymers can react rapidly in the karst cave, expand in volume, and form a foam-like solid, quickly filling the karst cave space and compacting the surrounding loose medium. This can form a ring-like foamed polymer grouting ring in the circumferential section at the seepage location near the karst cave in the underground project, forming a reliable sealing barrier to achieve the purpose of seepage prevention and leakage plugging. Permeable polymers can penetrate deep into small cracks along the first and second crack grouting pipes. The permeable polymer grouting material has low viscosity, good fluidity, and long reaction time, which can effectively penetrate into small cracks in the rock strata, fill the pores in the rock and soil, and cement them. This can form a ring-like permeable polymer grouting ring in the circumferential section at the seepage location where cracks develop at the far end of the underground project, forming a solid sealing layer, effectively preventing groundwater from seeping through cracks, and further improving the impermeability of the rock mass.
[0009] First, a foamed polymer is injected, allowing it to fully expand inside the karst cave and form a continuous, closed foam skeleton that completely fills the spaces of varying sizes, preventing the formation of large cavities. Then, a permeable polymer is injected, utilizing its low viscosity and high permeability to penetrate deep into micro-cracks for reinforcement, forming a tight-fitting plug layer that effectively seals water flow channels. The two materials complement each other: the foam provides volume filling and support, while the permeable polymer provides deep reinforcement and bonding, thus addressing both the needs for expansion and permeability.
[0010] The penetrating polymer used for sealing cracks is injected in stages through a second crack grouting pipe and a first crack grouting pipe of different lengths. The second crack grouting pipe is 70cm to 120cm longer than the first crack grouting pipe. This allows the penetrating polymer to be injected into the distant crack first, and then the penetrating polymer is injected again through the first crack grouting pipe. This avoids the situation where the near crack is not fully grouted due to the second crack grouting pipe being too long because the crack is far away. This ensures that the cavities and cracks are completely filled and sealed, and improves the quality of grouting and sealing.
[0011] The composite polymer grouting method for underground rock caverns provided by this invention can form a dual structure of "crack seepage prevention + cave sealing". It forms a comprehensive and effective seepage prevention system for the complex geological conditions of deep underground rock caverns, reduces the erosion and damage of seepage water to the cavern structure, and improves the safety and service life of underground engineering.
[0012] The composite polymer grouting method for underground rock caves provided by this invention can flexibly adjust the drilling layout, drilling depth, grouting pipe length, grouting pipe specifications, grouting material formula and grouting process parameters according to different cave scales and geological conditions. It has strong adaptability and versatility and is suitable for seepage treatment of various types of deep underground rock caves.
[0013] Preferably, in S3, foamed polymer is injected through the grouting pipe in the karst cave, and grouting is stopped when the grouting pressure reaches a predetermined value and the grouting volume no longer increases; penetrating polymer is injected through the second crack grouting pipe, and grouting is stopped when the grouting rate decreases significantly; penetrating polymer is injected through the first crack grouting pipe, and grouting is stopped when the grouting pressure reaches a predetermined value and the grouting volume no longer increases.
[0014] When the foamed polymer expands inside the cave to fit tightly against the cave wall, the grouting pressure reaches the predetermined value, and the grouting volume no longer increases, it indicates that the cave has been completely filled and the foam skeleton has formed a closed support structure, avoiding the risk of "residual voids". The permeable polymer is first injected into the distal crack through a longer second crack grouting pipe. When the flow rate suddenly drops, it indicates that the distal crack network has been fully infiltrated and filled. The real-time indicator of "flow rate change" can directly reflect the filling status of the material at depth. After the distal cracks are fully infiltrated, high-pressure grouting is performed again through a shorter first crack grouting pipe to fill the near-field cracks that may not have been completely sealed in the first grouting.
[0015] Preferably, in S2, the grouting holes in adjacent sections are staggered.
[0016] If grouting holes are arranged continuously along the same radial line, the grouting range of two holes is likely to overlap or be blank in that direction, forming a "short circuit" or "gap" in the grouting material, resulting in uneven grouting layer thickness. By arranging grouting holes in adjacent sections in a staggered manner, the grouting coverage areas of each hole can be staggered, ensuring that a continuous grouting closed zone is formed in both the circumferential and axial directions, eliminating "straight-through channels" and improving the sealing effect.
[0017] Preferably, the grouting holes are spaced 1.0m to 1.5m apart laterally and 1.0m to 1.5m apart longitudinally.
[0018] The preferred spacing between grouting holes is 1.0m×1.0m~1.5m×1.5m, which can effectively eliminate the "blind spots" of uninjected material in the rock strata and improve the grouting effect.
[0019] Preferably, the diameter of the grouting hole is 4cm to 4.5cm.
[0020] The preferred diameter of the grouting hole is 4cm to 4.5cm. This ensures sufficient space for the sealing grouting pipe, the karst cave grouting pipe, the first fracture grouting pipe, and the second fracture grouting pipe, while minimizing the damage to the surrounding rock during core sampling and reducing the risk of rock mass collapse or borehole collapse.
[0021] Preferably, the depth of the grouting hole is 4m to 5m.
[0022] The preferred grouting hole depth is 4m~5m, which can effectively cover most of the karst caves and the cracks around the underground project, accurately locate and effectively seal high-risk karst caves and cracks, while avoiding drilling into deeper hard parent rock or fractured zones, reducing secondary disturbance to stable deep rock masses, reducing the risk of borehole wall collapse and drilling, and ensuring construction safety.
[0023] Preferably, the length of the grouting pipe for the karst cave is 1m to 3m.
[0024] The preferred length of the grouting pipe for karst caves is 1m to 3m, which can flexibly adapt to the location of most karst caves and ensure that the end of the grouting pipe can be inserted into the middle or top of the cave, so that the grouting pipe can be accurately connected to the underground karst cave.
[0025] Preferably, the length of the first crack grouting pipe is 3m ± 0.5m.
[0026] The main cracks that develop in the shallow to medium-depth region are usually located within 2m to 3m of the underground engineering site. The preferred length of the first crack grouting pipe is 3m ± 0.5m, which can accurately reach this area and ensure that the permeable polymer can fully diffuse and infiltrate the crack network in the shallow to medium-depth region, thereby improving the grouting and sealing effect.
[0027] Preferably, the length of the second crack grouting pipe is 4.0m ± 0.5m.
[0028] The preferred length of the second crack grouting pipe is 4.0m ± 0.5m, which is shorter than the length of the grouting hole. This ensures that the second crack grouting pipe reaches the far end of the crack, ensuring that the far end crack is fully impregnated by the penetrating polymer first. This forms a segmented grouting strategy of "deep first, then shallow, deep and shallow linkage" with the first crack grouting pipe in the shallow and middle part, so that cracks of all depths can be uniformly reinforced. Furthermore, the preferred length of the second crack grouting pipe is 4.0m ± 0.5m. Combined with the working pressure of commonly used grouting equipment, this ensures that the pressure loss inside the pipe is controllable and that the grouting pressure at the deep part is sufficient.
[0029] Preferably, the direction of the grouting hole is oblique to the strike of the rock strata.
[0030] Rock strata strike is often accompanied by joints and seepage channels along the strike direction of bedding planes. Oblique drilling can cross more strike-oriented fractures at an oblique angle, increasing the number of intersections between grouting holes and fractures, connecting the drilled grouting holes with the seepage water, increasing the probability of grouting material entering the main seepage channel, and ensuring more uniform grouting coverage.
[0031] Compared with the prior art, the beneficial effects of the present invention are as follows: 1. This invention provides a composite polymer grouting method for underground rock caverns, which can form a dual structure of "crack seepage prevention + cave sealing". It forms a comprehensive and effective seepage prevention system for the complex geological conditions of deep underground rock caverns, reduces the erosion and damage of seepage water to the cavern structure, and improves the safety and service life of underground engineering. 2. This invention provides a composite polymer grouting method for underground rock caverns. Four grouting pipes (sealing grouting pipe, cavern grouting pipe, first crack grouting pipe, and second crack grouting pipe) are arranged in each grouting hole. Precise grouting of the cavern and surrounding cracks at different depths can be completed in one drilling, without the need for repeated drilling, reducing secondary disturbance to the rock mass, reducing the amount of drilling, and lowering the cost of seepage control. Attached Figure Description
[0032] Figure 1 Flowchart of composite polymer grouting method for underground rock caverns; Figure 2 A diagram showing the layout of grouting holes at different cross-sections in an underground tunnel project; Figure 3 A schematic diagram showing the staggered arrangement of grouting holes in adjacent sections; Figure 4 This is a typical cross-sectional layout diagram of grouting holes in an underground tunnel project. Figure 5 This is a schematic diagram of the grouting hole plan; Figure 6 This is a schematic diagram of the cross-section of the grouting hole.
[0033] Marked in the image: 1-Grouting hole, 11-Sealing grouting pipe, 12-Cave grouting pipe, 13-First crack grouting pipe, 14-Second crack grouting pipe, 15-Grouting cap, 2-Foamed polymer, 3-Permeable polymer, 100-Cave, 200-Crack, 300-Foamed polymer grouting ring, 400-Permeable polymer grouting ring. Detailed Implementation
[0034] 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.
[0035] 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.
[0036] 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.
[0037] 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.
[0038] 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.
[0039] 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.
[0040] Example 1 During the construction or operation of underground projects (such as underground defense, civil defense, tunnels, etc., this embodiment uses underground tunnel engineering as an example for explanation), rock caves formed by karst landforms are often encountered. When it rains or when there is abundant groundwater, the groundwater flows from top to bottom, gradually using rock fissures as seepage channels, and flows into the rock caves. After a period of time, water accumulates, passes through the initial support of the tunnel, and puts pressure on the tunnel lining. In severe cases, this can lead to seepage and leakage.
[0041] like Figure 1 As shown, this embodiment provides a composite polymer grouting method for underground rock caverns, including the following steps: S1: When water leakage is found in the tunnel during construction or operation, ground-penetrating radar is used to detect the location of water leakage in the tunnel, determine the location and extent of the karst cave 100 and the development of the surrounding cracks 200 (such as the spatial distribution characteristics of cracks 200, such as direction, inclination, and location).
[0042] S2: As Figures 2-6 As shown, a grouting hole 1 is drilled in the circumferential section at the seepage location. A sealing grouting pipe 11, a karst cave grouting pipe 12, a first fissure grouting pipe 13, and a second fissure grouting pipe 14 are arranged in the grouting hole 1, and a grouting cap 15 is installed. Among them, such as Figure 6 As shown, the length L2 of the second crack grouting pipe 14 is 70cm to 120cm longer than the length L1 of the first crack grouting pipe 13.
[0043] The grouting pipe 12 is used to inject grout into the karst cave 100, and the first fissure grouting pipe 13 and the second fissure grouting pipe 14 are used to inject grout into the fissure 200. It can be understood that in this embodiment, the drilling position of the grouting hole 1 can be appropriately adjusted according to the structural conditions of the seepage location detected by S1; the lengths of the karst cave grouting pipe 12, the first fissure grouting pipe 13, and the second fissure grouting pipe 14 can be adjusted according to the location of the karst cavity revealed during the specific drilling process.
[0044] S3: Sealing and grouting: First, use the sealing and grouting pipe 11 to grout and seal the hole; Then, foamed polymer 2 is injected through the grouting pipe 12. Grouting is stopped when the grouting pressure reaches a predetermined value and the grouting volume no longer increases. Figure 4 As shown, a foamed polymer grouting ring 300 is formed on the entire cross section at the seepage point of the karst cave near the tunnel end. It can be understood that the foamed polymer grouting ring 300 in this embodiment is not a standard ring around the tunnel, but a virtual ring formed by foamed polymer 2 injected into the karst cave 100 around the tunnel.
[0045] Then, the penetrating polymer 3 is injected through the second crack grouting pipe 14. Grouting is stopped when the grouting rate drops significantly. Specifically, for example, grouting can be stopped when the actual grouting flow rate drops to less than 10% of the initial grouting flow rate per unit time and remains below that for more than one minute.
[0046] Then, the penetrating polymer 3 is injected through the first fracture grouting pipe 13. When the grouting pressure reaches the predetermined value and the grouting volume no longer increases, the grouting is stopped. A penetrating polymer grouting ring 400 is formed across the entire cross-section at the seepage location where the fracture develops at the far end of the tunnel. It can be understood that in this embodiment, the penetrating polymer grouting ring 400 is not a standard ring surrounding the tunnel, but rather a virtual ring formed by the penetrating polymer 3 injected into the fracture 200 around the tunnel.
[0047] In this embodiment, the foaming polymer 2 can be a non-aqueous reactive two-component polyurethane or a water-reactive polyurethane foam grout commonly used in industrial production; the penetrating polymer 3 can be a low-viscosity polyurethane or acrylate grout commonly used in industrial production.
[0048] S4: Test the effectiveness of the seepage control and complete the construction.
[0049] The composite polymer grouting method for underground rock caverns provided in this embodiment arranges four grouting pipes (sealing grouting pipe 11, cavern grouting pipe 12, first fissure grouting pipe 13, and second fissure grouting pipe 14) in each grouting hole 1. Precise grouting of the cavern 100 and surrounding fissures 200 at different depths can be completed with a single drilling, eliminating the need for repeated drilling, reducing secondary disturbance to the rock mass, reducing the amount of drilling, and lowering the cost of seepage control. Grouting holes 1 are drilled in the circumferential section (i.e. the entire section) at the seepage location: foamed polymer 2 can enter the karst cave 100 along the grouting pipe 12. After the foamed polymer 2 reacts rapidly in the karst cave 100, it expands in volume and forms a foam-like solid, which quickly fills the space of the karst cave 100 and compacts the surrounding loose medium. It can form a ring-shaped foamed polymer grouting ring 300 in the circumferential section at the seepage location of the karst cave near the end of the tunnel, forming a reliable sealing barrier and achieving the purpose of preventing seepage and plugging leakage. The permeable polymer 3 can penetrate deep into the fine cracks 200 along the first crack grouting pipe 13 and the second crack grouting pipe 14. The permeable polymer 3 has low viscosity, good fluidity, and long reaction time, which can effectively penetrate into the fine cracks 200 of the rock strata, fill the pores in the rock and soil and cement them. It can form a ring-like permeable polymer grouting ring 400 around the tunnel cross section at the seepage location where the cracks develop at the far end of the tunnel, forming a solid sealing layer, effectively preventing groundwater from seeping through the cracks 200, and further improving the impermeability of the rock mass.
[0050] First, a foamed polymer 2 is injected, allowing it to fully expand inside the karst cave 100 and form a continuous, closed foam skeleton that completely fills the spaces of the karst cave 100 of varying sizes, preventing the retention of large-volume cavities. Then, a permeable polymer 3 is injected, utilizing its low viscosity and high permeability to penetrate deep into the micro-cracks 200 for wetting and reinforcement, forming a tight-fitting plug layer that effectively locks in water flow channels. The two materials complement each other: the foam provides volume filling and support, while the permeable provides deep reinforcement and bonding, thus addressing both the requirements of "expansion" and "permeability."
[0051] The penetrating polymer 3 used to seal the crack 200 is injected in stages through a second crack grouting pipe 14 and a first crack grouting pipe 13 of different lengths. The second crack grouting pipe 14 is 70cm to 120cm longer than the first crack grouting pipe 13. This allows the penetrating polymer 3 to be injected into the distal crack 200 first, and then the penetrating polymer 3 can be injected through the first crack grouting pipe 13. This avoids the situation where the proximal crack 200 is not fully grouted due to the distance of the crack 200 and the excessive length of the second crack grouting pipe 14. This ensures that the karst cave 100 and the crack 200 are completely filled and sealed, thus improving the quality of grouting and sealing.
[0052] The composite polymer grouting method for underground rock caverns provided in this embodiment can form a dual structure of "crack seepage prevention + cave sealing". It forms a comprehensive and effective seepage prevention system for the complex geological conditions of deep underground rock caverns, reducing the erosion and damage of seepage water to the cavern structure and improving the safety and service life of underground engineering.
[0053] The composite polymer grouting method for underground rock caves provided in this embodiment can flexibly adjust the drilling layout, drilling depth, grouting pipe length, grouting pipe specifications, grouting material formula and grouting process parameters according to different cave scales and geological conditions. It has strong adaptability and versatility and is suitable for seepage treatment of various types of deep underground rock caves.
[0054] Example 2 Based on Example 1, this example provides a detailed description of the relevant parameters of the grouting hole 1.
[0055] This embodiment provides a composite polymer grouting method for underground rock caverns, such as... Figure 2 ( Figure 2 The solid line indicates the location of grouting hole 1 in the current section, and the dashed line indicates the location of grouting hole 1 in the next section. Figure 3 As shown, the grouting holes 1 in adjacent sections are staggered.
[0056] If grouting holes 1 are arranged continuously along the same radial line of the tunnel, the grouting range of the two holes is prone to overlap or gaps in that direction, forming a "short circuit" or "gap" in the grouting material, resulting in uneven grouting layer thickness. By arranging grouting holes 1 in staggered positions in adjacent sections, the grouting coverage areas of each hole can be staggered, ensuring the formation of continuous grouting closure zones in both the circumferential and axial directions, eliminating "straight-through channels," and improving the sealing effect.
[0057] Furthermore, such as Figure 3As shown, the lateral spacing S1 of the grouting holes 1 is 1.0m~1.5m, and the longitudinal spacing S2 is 1.0m~1.5m. Setting the spacing of the grouting holes 1 to 1.0m×1.0m~1.5m×1.5m, preferably 1.5m×1.5m, can effectively eliminate the "blind spots" of uninjected material in the rock strata, improve the grouting effect, and save costs.
[0058] Furthermore, the diameter of the grouting hole 1 is 4cm to 4.5cm, preferably 4.2cm. The preferred diameter of the grouting hole 1 is 4cm to 4.5cm, which, while allowing sufficient space for the sealing grouting pipe 11, the cave grouting pipe 12, the first fracture grouting pipe 13, and the second fracture grouting pipe 14, minimizes the damage to the surrounding rock during core sampling, reducing the risk of rock mass collapse or borehole collapse.
[0059] Furthermore, the depth of grouting hole 1 is 4m to 5m. The preferred depth of grouting hole 1 is 4m to 5m, which can effectively cover most of the karst cave 100 and the surrounding cracks 200 of the tunnel, precisely locating and effectively sealing the high-risk karst cave 100 and cracks 200. Simultaneously, it avoids drilling into deeper hard parent rock or fractured zones, reducing secondary disturbance to stable deep rock masses, lowering the risk of borehole collapse and drilling, and ensuring construction safety.
[0060] Furthermore, the extension direction of grouting hole 1 is oblique to the strike of the rock strata. The strike of the rock strata is often accompanied by joints and seepage channels along the strike direction of the bedding plane. Oblique drilling can cross more strike fractures 200 at an oblique angle, increasing the number of intersections between grouting hole 1 and fracture 200, making the drilled grouting hole 1 connected with the seepage water, increasing the probability of grouting material entering the main seepage channel, and ensuring more uniform grouting coverage.
[0061] Furthermore, the length of the grouting pipe 12 is 1m to 3m, preferably 2.5m. The grouting pipe 12 can be a PVC grouting pipe. Preferably, the length of the grouting pipe 12 is 1m to 3m, which can flexibly adapt to the location of most karst caves 100, ensuring that the end of the grouting pipe can be inserted into the middle or top of the cave, so that the grouting pipe 12 can accurately connect to the underground karst cave 100.
[0062] Furthermore, the length of the first fracture grouting pipe 13 is 3m ± 0.5m, preferably 3.5m. Generally, the main fractures 200 developed in the shallow to medium-depth region are located within a 2m to 3m range near the underground engineering site. The preferred length of the first fracture grouting pipe 13 (3m ± 0.5m) ensures accurate access to this area, guaranteeing sufficient diffusion and infiltration of the permeable polymer 3 within the shallow to medium-depth fracture network 200, thereby improving the grouting and sealing effect.
[0063] Furthermore, the length of the second crack grouting pipe 14 is 4.0m ± 0.5m, preferably 4.5m. In this embodiment, both the first crack grouting pipe 13 and the second crack grouting pipe 14 can be grouting iron pipes. The preferred length of the second crack grouting pipe 14 (4.0m ± 0.5m) ensures that it reaches the distal crack 200, ensuring that the distal crack 200 is fully impregnated by the penetrating polymer 3 first. This forms a segmented grouting strategy of "deep first, then shallow, deep and shallow linkage" with the first crack grouting pipe 13 in the shallow-middle section, allowing uniform reinforcement of the crack 200 at all depths. Furthermore, the preferred length of the second crack grouting pipe 14 (4.0m ± 0.5m), combined with the working pressure of commonly used grouting equipment, allows for controllable pressure loss within the pipe, ensuring sufficient grout pressure at deeper depths.
[0064] 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 composite polymer grouting method for underground rock karst caves, characterized in that, Includes the following steps: S1: Detect the seepage location of underground engineering, determine the location and extent of the karst cave (100) and the development of the surrounding cracks (200); S2: Drill grouting holes (1) at the circumferential section of the seepage location, and arrange sealing grouting pipes (11), karst cave grouting pipes (12), first crack grouting pipes (13) and second crack grouting pipes (14) in the grouting holes (1), and install grouting caps (15). The length of the second crack grouting pipe (14) is 70cm to 120cm longer than the length of the first crack grouting pipe (13); The grouting pipe (12) is used to inject grout into the karst cave (100), and the first crack grouting pipe (13) and the second crack grouting pipe (14) are used to inject grout into the crack (200); S3: Grouting for sealing: First, use the grouting pipe (11) to grout and seal the hole; Then, foamed polymer (2) is injected through the grouting pipe (12) to form a foamed polymer grouting ring (300) on the entire cross section where there is karst cave seepage near the end. Then, the second crack grouting pipe (14) is used to inject the penetrating polymer (3), and the first crack grouting pipe (13) is used to inject the penetrating polymer (3) to form a penetrating polymer grouting ring (400) on the entire cross section where water seepage occurs at the far end of the crack. S4: Test the effectiveness of the seepage control and complete the construction.
2. The composite polymer grouting method for underground rock caverns according to claim 1, characterized in that, In S3, foamed polymer (2) is injected through the grouting pipe (12) in the karst cave. Grouting is stopped when the grouting pressure reaches the predetermined value and the grouting volume no longer increases. Penetrating polymer (3) is injected through the second crack grouting pipe (14). Grouting is stopped when the grouting rate decreases significantly. Penetrating polymer (3) is injected through the first crack grouting pipe (13). Grouting is stopped when the grouting pressure reaches the predetermined value and the grouting volume no longer increases.
3. The composite polymer grouting method for underground rock caverns according to claim 1, characterized in that, In S2, the grouting holes (1) in adjacent sections are staggered.
4. The composite polymer grouting method for underground rock caverns according to claim 3, characterized in that, Grouting holes (1) have a horizontal spacing of 1.0m~1.5m and a vertical spacing of 1.0m~1.5m.
5. The composite polymer grouting method for underground rock caverns according to claim 1, characterized in that, The diameter of the grouting hole (1) is 4cm~4.5cm.
6. A composite polymer grouting method for underground rock caverns according to claim 5, characterized in that, The grouting hole (1) has a depth of 4m~5m.
7. A composite polymer grouting method for underground rock caverns according to claim 6, characterized in that, The length of the grouting pipe (12) in the karst cave is 1m to 3m.
8. A composite polymer grouting method for underground rock caverns according to claim 7, characterized in that, The length of the first crack grouting pipe (13) is 3m ± 0.5m.
9. A composite polymer grouting method for underground rock caverns according to claim 8, characterized in that, The length of the second crack grouting pipe (14) is 4.0m ± 0.5m.
10. A composite polymer grouting method for underground rock caverns according to any one of claims 1 to 9, characterized in that, The direction of the grouting hole (1) is oblique to the strike of the rock strata.