A method for rapid dewatering and reinforcing of water-rich and weakly cemented roadway roof

Abstract

The application discloses a kind of rich water weakly cemented roadway roof rapid dewatering and reinforcement integration method, belong to mine water disaster prevention technical field.The purpose is to solve the problem of small dewatering range, low efficiency of traditional roof drainage hole method, and the long cycle, poor effect caused by the separation construction of "drainage first, reinforcement later".Technical scheme includes: accurate investigation and determination of water-rich roof;Construction roadway roof drainage hole and long-distance directional drilling into the middle of water-rich layer;Form a three-dimensional fracture network by sectional hydraulic fracturing in directional drilling;Inject high-pressure air to displace water and maintain pressure, promote the roof water to drain through the drainage hole;After the roof is basically dewatered, form a reinforced skeleton by directional drilling grouting;Finally, use the drainage hole to supplement grouting to form a permanent water-resisting and load-bearing shell and leave a monitoring hole.The application realizes the deep integration of dewatering and reinforcement, significantly expands the treatment range, greatly improves the drainage and reinforcement efficiency, and the construction is controllable and economical.

Description

Technical Field

[0001] This invention relates to the field of mine water hazard prevention and control and roadway surrounding rock control technology, and in particular to an integrated method for rapid dewatering and reinforcement of the roof of a water-rich and weakly cemented roadway. Background Technology

[0002] In coal mining, especially in western mining areas with unique geological conditions, roadways often encounter weakly cemented, water-rich roof strata. These strata have inherent engineering geological defects: poor cementation, low mechanical strength, and are major aquifers. Under the combined effects of engineering disturbance during roadway excavation and groundwater seepage, roadways beneath the water-rich roof strata are highly susceptible to continuous roof water seepage and runoff, which can lead to disasters such as water inrush and sand bursts in severe cases. This not only seriously threatens mine safety but also greatly restricts roadway excavation efficiency and long-term stability.

[0003] To address this challenge, traditional treatment methods typically employ a separate construction approach of "drainage first, then reinforcement," which has the following limitations:

[0004] Roof drainage hole method: This method involves constructing dense drainage holes in the roof of the tunnel. While simple and direct, this method has limited drilling depth, a small drainage range, and a slow speed, making it a passive drainage system. More importantly, drilling in weakly cemented rock strata is prone to hole collapse and blockage, leading to rapid failure of the drainage function.

[0005] Ordinary drilling method in adjacent roadways: Ordinary boreholes are drilled from adjacent, already stabilized roadways into the target water-rich roof for pressure relief or grouting. This method has uncontrollable drilling trajectories, making it difficult to accurately penetrate and cover the target aquifer. It often requires a large number of boreholes to ensure coverage, resulting in a large workload.

[0006] In summary, existing technologies struggle to achieve large-scale, rapid, and controllable active dewatering of weakly cemented, water-rich roof slabs. Furthermore, even if dewatering is completed, the strength of the water-weakened roof rock mass is significantly reduced, posing a risk of instability and necessitating secondary reinforcement. This fragmented approach of "drainage" and "reinforcement" results in a complex construction process, a lengthy cycle, and high overall costs.

[0007] Therefore, there is an urgent need in this field for an integrated method that can deeply integrate "active and efficient drainage" with "permanent structural reinforcement" to achieve rapid treatment of the roof of water-rich and weakly cemented roadways and reinforcement of the surrounding rock. Summary of the Invention

[0008] The purpose of this invention is to overcome the problems in the prior art and provide an integrated method for rapid drainage and reinforcement of the roof of water-rich, weakly cemented roadways. It aims to achieve rapid and controllable drainage of roof water through a synergistic process of "directional long-hole hydraulic fracturing to create fractures and enhance permeability + high-pressure gas-driven enhanced drainage + grouting reinforcement and sealing," while simultaneously completing the permanent reinforcement of the weakly cemented, water-rich roof rock mass, thus achieving the dual effect of "water control and roof reinforcement."

[0009] To achieve the aforementioned objectives, the present invention employs the following technical solution: an integrated method for rapid dewatering and reinforcement of the roof slab in water-rich, weakly cemented roadways, comprising the following steps:

[0010] S1. Precise geological exploration and stratigraphic positioning: Based on comprehensive geological data, on-site grouting tests and borehole television detection, accurately delineate the spatial location, thickness and water-rich characteristics of the weakly cemented water-rich roof above the tunnel roof.

[0011] S2. Construction of drainage holes in the roof of the roadway: Along the direction of the roadway to be dredged, drainage holes are constructed in the roof at the designed intervals to enter the weakly cemented, water-rich roof.

[0012] S3. Long-distance directional drilling: At least one long-distance directional borehole is drilled from the drilling site toward the weakly cemented water-rich roof. The trajectory of the long-distance directional borehole is arranged in the middle of the weakly cemented water-rich roof and is parallel or oblique to the roadway direction at a small angle.

[0013] S4. Directional segmented hydraulic fracturing: Segmented jet fracturing and hydraulic fracturing are carried out in the long-distance directional borehole to form a three-dimensional fracture network in the target rock strata.

[0014] S5. High-pressure air displacement and pressure maintenance: High-pressure air is continuously injected into the long-distance directional borehole after fracturing to displace the fracturing fluid and rock water. Then the borehole is sealed and its internal high air pressure is maintained to promote the drainage of topsoil water through the drainage holes.

[0015] S6. Long-distance directional drilling and grouting reinforcement: After confirming that the water in the top slab has been basically drained, grout is injected into the crack network after drainage in step S5 through the long-distance directional drilling to form a reinforced skeleton structure.

[0016] S7. Grouting and sealing of drainage holes in the roadway roof: Grouting is performed on the roadway roof rock strata and drainage holes through the drainage holes constructed in step S2 to form a permanent water-proof and load-bearing shell, and some drainage holes are retained in sections as monitoring holes according to proportion.

[0017] Furthermore, in step S2, the drainage hole is formed by two drilling operations: the first drilling reaches the bottom of the weakly cemented water-rich roof and continues drilling for 20-30cm, then a rigid casing is lowered and grout is injected to solidify the casing, thereby constructing a reliable isolation layer to effectively prevent water in the water-rich roof from seeping down along the borehole, avoiding the weakening and expansion of the directly topped mudstone due to water contact, and ensuring the stability of the roadway roof foundation layer; the second drilling continues inside the casing to the middle of the weakly cemented water-rich roof.

[0018] Furthermore, in step S2, the drainage holes are arranged in rows, with each row including three holes. The middle hole is drilled perpendicular to the top slab, while the holes on both sides are drilled at an angle of 15° to 30° to the direction perpendicular to the top slab. This three-dimensional hole arrangement, compared to a single vertical hole, can intercept and guide water flow in the top slab rock strata over a larger area, forming a more efficient local drainage network, thereby accelerating the collection and discharge process of water from the top slab.

[0019] Furthermore, in step S2, the design spacing of the drainage holes is determined based on 2 to 2.5 times the grout diffusion radius obtained through on-site grouting tests in step S1. This design basis ensures that the influence areas of adjacent drainage holes (and subsequently, as grouting holes) can overlap reasonably. While avoiding waste caused by excessively dense drilling, it also prevents the formation of untreated weak zones due to excessive hole spacing, achieving a balance between the economy and reliability of drainage and reinforcement coverage.

[0020] Furthermore, in step S3, the trajectory of the long-distance directional borehole is arranged in the middle of the weakly cemented water-rich roof, and maintains a vertical distance of 3-8m from the outline of the roadway roof. This design allows the borehole to be precisely located in the core area of ​​the aquifer, fully utilizing its high-pressure air-driven drainage and grouting reinforcement functions as a "main channel"; at the same time, maintaining a certain safe vertical distance avoids construction disturbance to the direct roof of the roadway and ensures safe space for subsequent roadway excavation or maintenance operations.

[0021] Furthermore, in step S4, the segmented jet fracturing and hydraulic fracturing involves first using a high-pressure water jet to cut an initial guide seam on the borehole wall, and then performing hydraulic fracturing to expand the guide seam into a radial three-dimensional fracture network to enhance the connectivity of the drainage channels. Through the pre-cut guide seam, the initiation position and expansion direction of the hydraulic fractures can be precisely controlled, resulting in a more regular and extended fracture network. This significantly enhances the overall permeability of the water-rich roof, creating superior channel conditions for subsequent high-pressure air-driven water discharge and grout injection.

[0022] Furthermore, in step S5, the pressure of the high-pressure air is less than the pressure threshold that would cause the weakly cemented water-rich roof to continue fracturing; the sealing section of the long-distance directional borehole is located in the borehole section below the weakly cemented water-rich roof. Controlling the air pressure within the safe threshold is to avoid unnecessary secondary damage to the rock strata while efficiently displacing the fracture water; selecting the sealing location below the water-rich layer ensures the reliability of the seal and facilitates the creation of a high-pressure drilling environment.

[0023] Furthermore, in step S6, the injected grout is a chemical grout or a cement-based grout, and the grouting pressure is higher than the pressure maintained in step S5. After basic desiccation, using this type of low-viscosity, high-permeability grout and injecting it at a pressure slightly higher than the original pressure maintainer can fully utilize the drained fracture network, allowing the grout to effectively penetrate deep into the micro-fractures, thereby achieving deep cementation and strengthening of the rock mass, constructing a stable reinforced framework, and permanently sealing the main water-conducting channels.

[0024] Furthermore, in step S7, cement-based grout is injected through the drainage holes to seal residual cracks and enhance the integrity and water tightness of the roof. This supplementary grouting aims to seal any water-conducting cracks that may remain after grouting through the main channel and to consolidate the borehole itself, forming a complete, dense, and high-strength permanent protective shell on the roadway roof to completely isolate the water source and bear the surrounding rock pressure for a long time.

[0025] Furthermore, in step S7, the number of drainage holes retained for monitoring purposes accounts for 5-10% of the total number of drainage holes. Retaining a small number of drainage holes as long-term monitoring points can provide a direct window for assessing the subsequent stability of the roof, residual humidity, or potential water pressure changes, thereby achieving long-term verification of the treatment effect and dynamic monitoring of the safety status.

[0026] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0027] This invention addresses the shortcomings of existing dewatering technologies, such as low efficiency and limited scope. Through the synergy of long-distance directional drilling and hydraulic fracturing, a large-scale three-dimensional fracture network is actively constructed in weakly cemented, water-rich roof slabs. This transforms the seepage channels of roof water from natural fissures into an artificially controlled fracture network, expanding the drainage radius several times and increasing the drainage speed by orders of magnitude. High-pressure air injection rapidly displaces the fracturing fluid and residual water in the rock strata, establishing a stable high-pressure field within the fracture system, forming an "airlock barrier." This not only prevents external groundwater from seeping into the tunnels but also continuously drives residual water to migrate and drain through the drainage holes. This achieves a rapid and controllable transformation of the roof strata from a saturated to a dry state, fundamentally solving the technical bottlenecks of traditional drainage hole methods, such as small drainage range, slow speed, and susceptibility to hole collapse failure.

[0028] This invention addresses the shortcomings of existing technologies where the "drainage" and "reinforcement" processes are separated. It deeply integrates drainage and reinforcement, forming a complete technical chain of "crack creation and permeability enhancement—air-driven drainage—grouting consolidation." The dry environment created after high-pressure air drains the crack network effectively avoids the dilution and blockage of the grout by residual water in traditional grouting, significantly improving the grout's permeability and bonding strength. Low-viscosity, high-permeability grout is first injected through directional drilling to form a reinforced structure with the borehole as its framework, permanently sealing the main water channels. Then, high-strength grout is injected again through the roof drainage holes to fill residual micro-cracks and the boreholes themselves, ultimately forming a complete, dense, and permanent water-resistant bearing shell on the tunnel roof. This solves the problems of uncontrollable trajectory and poor secondary reinforcement effect of traditional ordinary drilling methods.

[0029] This invention offers significant economic and technical advantages: long-distance directional drilling covers a large area in a single operation, greatly reducing the amount of work required for dense conventional drilling, shortening the water control period, and lowering construction safety risks. Hydraulic fracturing parameters can be precisely controlled according to formation characteristics, allowing for directional fracture propagation and avoiding destructive impacts on non-target strata. Attached Figure Description

[0030] The accompanying drawings are provided to further illustrate the invention and form part of the specification. They are used together with the embodiments of the invention to explain the invention and do not constitute a limitation thereof.

[0031] Figure 1 This is a schematic diagram of a hydrophobic hole.

[0032] Figure 2 A schematic diagram of a hydrophobic borehole in a weakly cemented, water-rich roof slab.

[0033] Figure 3 This is a schematic diagram of the tunnel's orientation.

[0034] Figure 4 This is a schematic diagram of the tunnel cross-section.

[0035] The attached diagram is labeled as follows: 1. Coal seam; 2. Immediate roof mudstone; 3. Weakly cemented water-rich roof; 4. Drainage hole; 5. Rigid casing; 6. Grouting section; 7. Adjacent stable roadway; 8. Roadway to be drained; 9. Drilling site; 10. Long-distance directional borehole; 11. Direction of water flow. Detailed Implementation

[0036] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and embodiments. Of course, the specific embodiments described herein are merely illustrative and not intended to limit the invention.

[0037] This embodiment provides an integrated method for rapid dewatering and reinforcement of the roof of a water-rich, weakly cemented roadway, including the following steps:

[0038] S1. Precise Engineering Geological Exploration and Stratigraphic Location: Through comprehensive analysis of geological borehole, geophysical, and tunnel exposure data, accurately delineate the spatial strata, thickness, water content, and main water-rich sections of the weakly cemented, water-rich roof. Select representative tunnel sections to drill grouting holes, extending to the middle of the weakly cemented, water-rich roof, and conduct on-site grouting tests to obtain measured grouting parameters (such as grout diffusion radius, grouting pressure, and grout intake). Utilize borehole television or in-hole radar to identify primary joints and fracture zones in the roof strata, providing a basis for subsequent directional drilling trajectory design.

[0039] S2. Arrangement and Construction of Drainage Holes in the Roof of the Tunnel: Drainage holes are arranged in the roof at the designed spacing along the direction of the tunnel to be drained. The depth of the drainage holes should reach the middle of the weakly cemented, water-rich roof. Light-duty drilling rigs can be used for drilling. Initially, the holes are used for drainage, and later they will serve as grouting holes and monitoring holes. The designed spacing can be considered to be 2 to 2.5 times the diffusion radius of the grout from the field grouting test in S1.

[0040] The drainage hole is drilled in two stages, as shown in the example. Figure 1 As shown, the drilling steps are as follows: Drill a hole to the bottom of the weakly cemented, water-rich roof, penetrating 20-30cm into the weakly cemented, water-rich roof. Insert a rigid casing into the drainage hole, with the upper end of the casing reaching the bottom of the hole and the lower end extending 20-30cm beyond the hole opening. An external pipeline can be connected to guide the water flow into the roadway drainage ditch. Seal the borehole by grouting from the lower end of the casing to solidify it. Then continue drilling towards the bottom of the hole inside the casing and continue drilling to the middle of the weakly cemented, water-rich roof. The drainage hole is drilled twice, mainly to prevent water from flowing into the mudstone directly above the coal seam during the construction of the drainage hole under conditions of weakly cemented mudstone directly above the coal seam. This would cause the mudstone directly above the coal seam to weaken, expand, and disintegrate upon contact with water. Figure 1 In the diagram, 1 represents the coal seam, 2 represents the immediate roof mudstone, 3 represents the weakly cemented water-rich roof, 4 represents the drainage hole, 5 represents the rigid casing, and 6 represents the grouting section.

[0041] Each row of drainage holes is designed with 3 holes. The middle drainage hole is installed perpendicular to the top plate, while the drainage holes on both sides are installed at a certain angle to the vertical direction of the top plate. The recommended angle is 15~30°.

[0042] S3. Long-distance directional drilling design and construction: Using a suitable location near the end of a stabilized roadway or a roadway to be dredged as the drilling site, long-distance directional drilling is carried out. One or more long-distance directional boreholes are drilled into the weakly cemented water-rich layer of the roof, parallel to or slightly oblique to the roadway direction. After reaching the weakly cemented water-rich roof, drilling continues parallel to the roadway direction. The borehole trajectory is designed in the middle of the water-rich layer, at a certain vertical distance (e.g., 3-8m) from the roadway roof outline, forming a "main channel" covering the entire length of the roadway or key sections, such as... Figure 2 , Figure 3As shown, 1 is the coal seam, 2 is the immediate roof mudstone, 3 is the weakly cemented water-rich roof, 4 is the drainage hole, 7 is the adjacent stable roadway, 8 is the roadway to be drained, 9 is the drilling site, and 10 is the long-distance directional borehole.

[0043] S4. Directional Segmented Hydraulic Fracturing: In long-distance directional boreholes, expandable packers are used for segmented isolation. For each selected segment (preferably in water-rich layers), jet fracturing and hydraulic fracturing are performed. The jet operation first uses a high-pressure water jet to cut an initial pilot fracture in the borehole wall, followed by hydraulic fracturing to expand the pilot fracture into a radial, three-dimensional fracture network, ensuring that the fractures extend within the target layer and connect with the original fractures.

[0044] S5. High-Pressure Air Displacement and Pressure Maintenance: After hydraulic fracturing, high-pressure, high-flow-rate compressed air is continuously injected into the long-distance directional borehole through the air injection pipe. The high-pressure air rapidly displaces the fracturing fluid from the fracture network. The long-distance directional borehole is promptly sealed. The high-pressure air drives the water in the roof to move towards both sides of the long-distance directional borehole through the fracture network and rock pores. The roof water accumulates on the roof directly above the roadway and is discharged through the drainage holes in the roadway roof. After there is no continuous water outflow from the borehole opening, the drainage holes are promptly sealed. Gas is continuously replenished into the long-distance directional borehole to maintain a stable high-pressure state within the entire borehole-fracture system. This high-pressure state acts as an "airlock" and "pressure barrier," preventing the seepage of external groundwater towards the roadway on the one hand, and using the pressure gradient to continuously drive the residual formation water to slowly migrate and discharge towards the lower-pressure drainage holes in the roadway on the other hand. The direction of free water flow in the roof of the high-pressure air-driven roadway is as follows. Figure 4 As shown, observe the changes in water output and quality from the drainage holes in the tunnel roof. When no large, continuous flow of water emerges from any of the drainage holes, and only dripping or dampness is observed, it indicates that the free water in the weakly cemented, water-rich rock strata surrounding the tunnel has been largely drained, and the rock mass is in a state of "residual water content." Long-distance directional drilling should be prioritized in the section drilled below the weakly cemented, water-rich roof. The high-pressure air pressure should be lower than the pressure threshold for continued fracturing of the weakly cemented, water-rich roof. Figure 4 1 is the coal seam, 2 is the immediate roof mudstone, 3 is the weakly cemented water-rich roof, 4 is the drainage hole, 8 is the roadway to be drained, 9 is the drilling site, 10 is the long-distance directional borehole, and 11 is the direction of water flow.

[0045] S6. Long-distance directional drilling grouting reinforcement of the main channel: After confirming that the top slab is basically dehydrated, inject low-viscosity, high-permeability chemical grout (such as modified epoxy resin, polyurethane, etc.) or ultrafine cement-based grout into the fracture network and connecting primary fractures through the original long-distance directional drilling. The grouting pressure is slightly higher than the original pressure holding pressure. The grout penetrates into the micro-fractures, cements the weakly cemented rock mass, and forms a "reinforced skeleton structure" with the long-distance directional drilling as the framework, permanently sealing the main water-conducting channel.

[0046] S7. Grouting and Sealing of Drainage Holes in the Tunnel Roof: After the grout in the main channel has solidified, supplementary grouting is performed using the drainage holes in the tunnel roof constructed in step S2. High-strength cement-based grout is injected to fill and reinforce the residual water-conducting cracks in the weakly cemented, water-rich floor and the boreholes themselves, forming a complete and dense "permanent waterproof-bearing shell" that keeps the roof in a long-term drained and stable state. 5-10% of the drainage holes will be retained in sections for future monitoring.

[0047] In summary, this invention discloses an integrated method for rapid dewatering and reinforcement of the roof of a water-rich, weakly cemented roadway. Through precise exploration, directional fracturing, air-driven drainage, and grouting reinforcement, the method achieves a unified approach to both dewatering and reinforcement processes. First, through geological data analysis and on-site grouting tests, the weakly cemented, water-rich roof strata are precisely delineated. Drainage holes are constructed along the roadway strike, employing a two-stage drilling process to prevent water infiltration from the roof and weakening of the mudstone. Based on this, long-distance directional drilling is performed from the drilling site to the middle of the water-rich roof. A large-scale three-dimensional fracture network is actively constructed using segmented jet fracturing and hydraulic fracturing techniques, transforming the roof strata into controllable water-conducting channels. Subsequently, high-pressure air is injected to rapidly displace the fracturing fluid and residual water in the strata. Maintaining high pressure within the closed system forms an "airlock barrier," preventing external water infiltration and continuously driving residual water out through the drainage holes, thus achieving rapid and controllable dewatering of the roof. After dewatering is completed, a low-viscosity, high-permeability grout is first injected through directional drilling to form a reinforced structure with the boreholes as its framework, permanently sealing the main water channel. Then, high-strength grout is injected through the drainage holes to fill any remaining fissures, ultimately forming a complete and dense permanent water-resistant shell on the tunnel roof. Some drainage holes are retained as monitoring holes. This invention solves the problems of small dewatering range and low efficiency in existing technologies, significantly improving the treatment effect and construction economy, and providing an efficient and reliable technical solution for the prevention and control of water hazards on the roof of tunnels in weakly cemented soft rock strata.

[0048] 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, improvements, etc., 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 rapid dewatering and reinforcement of the roof slab in water-rich, weakly cemented roadways, characterized in that, Includes the following steps: S1. Precise geological exploration and stratigraphic positioning: Based on comprehensive geological data, on-site grouting tests and borehole television detection, accurately delineate the spatial location, thickness and water-rich characteristics of the weakly cemented water-rich roof above the tunnel roof. S2. Construction of drainage holes in the roof of the roadway: Along the direction of the roadway to be dredged, drainage holes are constructed in the roof at the designed intervals to enter the weakly cemented, water-rich roof. S3. Long-distance directional drilling construction: At least one long-distance directional borehole is constructed from the drilling site toward the weakly cemented water-rich roof. The trajectory of the long-distance directional borehole is arranged in the middle of the weakly cemented water-rich roof and is parallel or oblique to the roadway direction at a small angle. S4. Directional segmented hydraulic fracturing: Segmented jet fracturing and hydraulic fracturing are carried out in the long-distance directional borehole to form a three-dimensional fracture network in the target rock strata. S5. High-pressure air displacement and pressure maintenance: High-pressure air is continuously injected into the long-distance directional borehole after fracturing to displace the fracturing fluid and rock water. Then the borehole is sealed and its internal high air pressure is maintained to promote the drainage of top plate water through the drainage holes. S6. Long-distance directional drilling and grouting reinforcement: After confirming that the water in the top slab has been basically drained, grout is injected into the crack network after drainage in step S5 through the long-distance directional drilling to form a reinforced skeleton structure. S7. Grouting and sealing of drainage holes in the roadway roof: Grouting is performed on the roadway roof rock strata and drainage holes through the drainage holes constructed in step S2 to form a permanent water-proof and load-bearing shell, and some drainage holes are retained in sections as monitoring holes according to proportion.

2. The integrated method for rapid dewatering and reinforcement of the roof of a water-rich, weakly cemented roadway according to claim 1, characterized in that, In step S2, the drainage hole is formed by two drilling operations: the first drilling is carried out to the bottom of the weakly cemented water-rich top plate and continues to drill for 20-30cm, a rigid casing is lowered and grout is injected to fix the casing, so as to prevent water from the top plate from flowing into the lower mudstone along the borehole and causing weakening; the second drilling continues inside the casing to the middle of the weakly cemented water-rich top plate.

3. The integrated method for rapid dewatering and reinforcement of the roof of a water-rich, weakly cemented roadway according to claim 2, characterized in that, In step S2, the drainage holes are arranged in rows, with each row including 3 holes. The middle hole is drilled perpendicular to the top plate, and the holes on both sides are drilled at an angle of 15° to 30° with the direction perpendicular to the top plate.

4. The integrated method for rapid dewatering and reinforcement of the roof of a water-rich, weakly cemented roadway according to claim 1, characterized in that, In step S2, the design spacing of the hydrophobic holes is determined based on 2 to 2.5 times the grout diffusion radius obtained through on-site grouting tests in step S1.

5. The integrated method for rapid dewatering and reinforcement of the roof of a water-rich, weakly cemented roadway according to claim 1, characterized in that, In step S3, the trajectory of the long-distance directional borehole is arranged in the middle of the weakly cemented water-rich roof, and maintains a vertical distance of 3 to 8 m from the outline of the roadway roof.

6. The integrated method for rapid dewatering and reinforcement of the roof of a water-rich, weakly cemented roadway according to claim 1, characterized in that, In step S4, the segmented jet fracturing and hydraulic fracturing involves first using high-pressure water jets to cut an initial guide seam on the borehole wall, and then performing hydraulic fracturing to expand the guide seam into a radial three-dimensional fracture network to enhance the connectivity of the drainage channel.

7. The integrated method for rapid dewatering and reinforcement of the roof of a water-rich, weakly cemented roadway according to claim 1, characterized in that, In step S5, the pressure of the high-pressure air is less than the pressure threshold that causes the weakly cemented water-rich roof to continue fracturing; the sealing section of the long-distance directional drilling is located in the drilling section below the weakly cemented water-rich roof.

8. The integrated method for rapid dewatering and reinforcement of the roof of a water-rich, weakly cemented roadway according to claim 1, characterized in that, In step S6, the injected grout is a chemical grout or a cement-based grout, and the grouting pressure is higher than the pressure maintained in step S5.

9. The integrated method for rapid dewatering and reinforcement of the roof of a water-rich, weakly cemented roadway according to claim 1, characterized in that, In step S7, cement-based grout is injected through the hydrophobic holes to seal residual cracks and enhance the integrity and waterproofing of the top slab.

10. The integrated method for rapid dewatering and reinforcement of the roof of a water-rich, weakly cemented roadway according to claim 1, characterized in that, In step S7, the number of drainage holes retained for use as monitoring holes accounts for 5 to 10% of the total number of drainage holes.

Images