Full-space bolting-grouting cooperative control method for gradient failure of roadway surrounding rock
By adding grouting sleeves to the ends of anchor cables and designing gradient grouting, the problems of low construction efficiency and insufficient reinforcement in traditional roadway support were solved, realizing the coordinated operation of anchoring and grouting, and improving the overall reinforcement effect and stability of the roadway surrounding rock.
Patent Information
- Application Number
- CN202610193978.7
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2026-02-10
- Publication Date
- 2026-04-24
AI Technical Summary
Traditional tunnel support technology suffers from problems such as low construction efficiency, poor reinforcement targeting, easy failure of anchor cable ends, and insufficient overall consolidation of surrounding rock. In particular, in the case of gradient failure of surrounding rock, traditional anchoring and grouting cannot be carried out simultaneously, resulting in grout loss or insufficient penetration, thus limiting the anchoring effect.
Grouting sleeves are added to the ends of the anchor cables. Sleeves of different lengths are designed to adapt to the gradient distribution of fractures in the surrounding rock, so as to realize shallow and deep gradient grouting. Combining mechanical anchoring and grouting functions, grouting is carried out through the lateral external interface. Cement grout with different particle sizes is used. Dynamic supplementary grouting is carried out by monitoring changes in the surrounding rock, so as to construct a full-space anchoring and grouting collaborative support system.
It improved construction efficiency, enhanced the shear resistance of anchor cables, achieved overall reinforcement of the surrounding rock, avoided problems of grout loss and insufficient penetration, and improved the reliability and stability of the support structure.
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Abstract
Description
Technical Field
[0001] This invention belongs to the field of mine roadway surrounding rock control technology in geotechnical engineering, specifically involving a full-space anchoring and injection coordinated control method for gradient failure of roadway surrounding rock. Background Technology
[0002] In coal mines, metal mines, and other underground engineering projects, the stability of the surrounding rock is the cornerstone of engineering safety. However, complex geological environments and mining-induced stresses can easily lead to deformation and failure of the surrounding rock, with "gradient failure" being a typical pattern. This failure manifests as follows: the shallow surrounding rock near the excavation face experiences stress concentration and intense disturbance, resulting in large fissures, even forming macroscopic fissures; while the deep surrounding rock further away from the face experiences less disturbance, maintains a more intact structure, and has smaller fissures, mostly micro-fissures. This gradient distribution characteristic, with fissures gradually decreasing from shallow to deep, places higher demands on roadway support. Moreover, existing grouting technologies are ill-suited to this gradient fissure. Traditional methods often employ a single grout and uniform parameters for overall grouting, leading to: at shallow, large-fissure fissures, the grout may overflow and leak due to flowability or particle size mismatch, resulting in ineffective consolidation. Statistics show that in some fractured surrounding rock, the grout loss rate can reach over 30%, causing material waste and environmental pollution. In deep, fine cracks, the grout may be difficult to penetrate due to excessively large particle size, resulting in insufficient reinforcement and failure to fully realize its potential.
[0003] Furthermore, in traditional support techniques, anchor bolt installation and grouting are independent and cannot be synchronized. This not only increases the complexity of the procedures, the workload, and the time required for construction, but also means that after the anchor bolts are installed, the surrounding rock fissures at their ends may continue to develop. Without timely grouting reinforcement, the integrity of the surrounding rock is extremely poor. If broken rock blocks near the anchor bolt tray fall off, the anchoring foundation is lost, and the anchoring effect fails. At the same time, traditional single-anchor bolt support has significant limitations. It only connects shallow unstable rock masses with deep stable rock masses through radial constraint, and cannot actively fill surrounding rock fissures. It lacks the grouting function synchronized with anchoring, making it difficult to reinforce the surrounding rock in the anchor bolt installation area. This results in a loose bond between the anchor bolt and the surrounding rock, limiting the overall support effect. Moreover, the anchor bolt ends are the weakest link in the support system. Under mining stress, the surrounding rock is prone to shear displacement. Due to stress concentration and rock fragmentation, the ends are highly susceptible to shear failure, weakening the anchoring effect and even leading to support failure, reducing reliability and long-term stability.
[0004] In summary, there is an urgent need in this field for an innovative solution to address the technical challenges of traditional step-by-step construction methods, such as low efficiency, poor reinforcement targeting, easy failure of anchor cable ends, and insufficient overall consolidation of surrounding rock. This invention is proposed against this backdrop. By adding a grouting sleeve to the end of the anchor cable, it overcomes the bottleneck of the inability to simultaneously perform anchoring and grouting, achieving coordinated anchoring and grouting operations. This solution aims to combine the mechanical anchoring function of the anchor cable with the precise grouting function of the surrounding rock at its end, achieving effective filling of shallow, large-aperture fractures and deep penetration reinforcement of deep, micro-fractures. Simultaneously, this design also enhances the shear resistance of the anchor cable ends, ultimately constructing a comprehensive support system capable of fully addressing gradient failure of the surrounding rock in roadways. This invention aims to provide a more scientific, efficient, and economical method for the coordinated control of anchoring and grouting across the entire space in response to gradient failure of the surrounding rock in roadways. Summary of the Invention
[0005] This invention aims to overcome the shortcomings of existing roadway support technologies and provide an innovative, full-space anchoring and grouting coordinated control method for gradient failure of surrounding rock in roadways. The core of this method lies in the ingenious design of the grouting sleeve structure, which deeply integrates the mechanical anchoring function of traditional anchor cables with the grouting reinforcement function of the surrounding rock.
[0006] To achieve the above objectives, this method adds a grouting sleeve to the end of the anchor cable, with a grouting port connected to the side of the sleeve. This overcomes the bottleneck of traditional methods that prevent simultaneous anchoring and grouting, enabling coordinated anchoring and grouting. Based on the gradient distribution characteristics of the surrounding rock fissure opening, the grouting sleeve is designed with different lengths to achieve gradient grouting at shallow and deep depths. Ordinary cement grout is injected into the shallow surrounding rock, while ultrafine cement is injected into the deep surrounding rock. Furthermore, the grouting sleeve increases the shear strength of the anchor cable, preventing shear failure at the end.
[0007] To achieve the above objectives, the technical solution adopted by the present invention is as follows:
[0008] 1. The support scheme is designed according to the tunnel size, surrounding rock mechanical properties and ground stress conditions. The shallow and deep grouting casing and anchor cable are arranged alternately and located in the middle of two rows of traditional anchor bolt support. Both anchor bolts and anchor cables are end anchored. This arrangement aims to optimize stress distribution and build a support foundation with balanced stress.
[0009] 2. Drilling measurements of fracture development patterns in surrounding rock and determination of grouting casing length: Drill holes of a certain depth in the center of the roof and the middle of both sides of the roadway. Use a borehole sight and resistivity detector to measure the fracture gradient distribution patterns in the roof and sides, especially the relationship between fracture aperture and depth. Based on the measured fracture aperture distribution patterns in the surrounding rock and the grout permeability characteristics, determine the length of the grouting casing in the roof and sides to ensure that the grout outlet of the casing accurately corresponds to the target fracture area and achieve precise grouting.
[0010] 3. Grouting sleeve installation: The shallow grouting pipe with rubber sealing sleeve is sleeved on the end of the anchor rod or anchor cable, and then inserted into the borehole. The tray is installed on the outside and the pre-tightening force is applied to tighten the nut or tighten the lock. The rubber sealing sleeve fits tightly against the end wall of the borehole. Its conical design ensures a reliable seal and effectively prevents grout leakage during the grouting process.
[0011] 4. Deep and shallow grouting: Grouting is carried out through the side-to-outside interface of the grouting pipe. For shallow grouting, a shorter casing is used, and ordinary cement is injected. The water-cement ratio and additives are determined according to the characteristics of shallow large-aperture fractures to ensure that the grout fully fills and consolidates the fractured surrounding rock. For deep grouting, a longer casing is used, and ultrafine cement is injected. Its particle size is smaller and its permeability is stronger. The water-cement ratio and additives are precisely proportioned according to the characteristics of deep micro-fractures. When the grout overflows from the nearby surrounding rock, grouting is stopped based on the monitoring results of acoustic waves or resistivity sensors.
[0012] 5. Dynamic monitoring and supplementary grouting of surrounding rock fissures: Dynamic monitoring of surrounding rock fissures in boreholes. When the surrounding rock fissures are further developed due to mining, and the monitoring data reaches the preset warning threshold, local supplementary gradient grouting is carried out according to the original design casing length, grout type and grouting pressure parameters to construct a full-space support structure with anchor bolt and cable synergistic bearing and shallow and deep gradient grouting, so as to achieve effective control of surrounding rock gradient damage.
[0013] Compared with existing conventional devices, the beneficial effects of the present invention are as follows:
[0014] First, a grouting sleeve is added to the end of the anchor cable, with the grouting port connected to the side of the sleeve. This breaks through the bottleneck that traditional anchoring and grouting cannot be carried out at the same time. Grouting can improve the integrity of the surrounding rock and prevent the pre-tightening force from failing at the end of the anchor due to the fracture of the surrounding rock. The combined effect of anchoring and grouting improves the integrity and stability of the surrounding rock.
[0015] Secondly, based on the gradient distribution characteristics of the surrounding rock fissure opening from shallow to deep, the present invention designs grouting sleeves of different lengths to achieve gradient grouting at shallow and deep depths. Ordinary cement grout is injected into the shallow surrounding rock, while ultrafine cement is injected into the deep surrounding rock. This solves the problem that traditional single grouting may result in the deep part not being able to be grouted due to the small fissure opening, and the shallow part being prone to grout leakage due to the large fissure opening.
[0016] Third, by adding a grouting sleeve to the end of the traditional anchor cable, the present invention not only endows the anchor cable with grouting function, but more importantly, the sleeve structure can significantly improve the shear resistance of the anchor cable, effectively solving the problem that traditional anchor cables are prone to shear failure at the end, thereby improving the reliability of the support structure.
[0017] Fourth, this invention enables the coordinated operation of anchor cable anchoring and grouting, eliminating the need for separate grouting drills. This overcomes the technical limitations of traditional step-by-step anchoring and grouting construction, greatly reduces the amount of drilling work, and significantly improves construction efficiency. Attached Figure Description
[0018] Figure 1 A method for coordinated control of gradient failure of surrounding rock in roadways using full-space anchoring and injection
[0019] Figure 2 Top view of the anchor cable arrangement of the method described in this invention
[0020] Figure 3 Cross-sectional view of the anchor bolt grouting sleeve according to the method of the present invention
[0021] Figure 4 Flowchart of the technical solution of this invention
[0022] The components in the attached diagram are labeled as follows: 1. Anchor cable, 2. Rubber gasket, 3. Anchor bolt, 4. Grouting sleeve, 5. Rubber sealing sleeve, 6. Roadway side, 7. Roadway, 8. Anchor cable tray, 9. Roof, 10. Anchor bolt tray, 11. W-shaped steel strip, 12. Grout outlet, 13. Lateral outward interface of grouting pipe. Specific implementation methods
[0023] To address the problems in existing coal mine roadway grouting construction, such as easy grout overflow and loss, inability of traditional anchor bolts and cables to achieve grouting reinforcement, easy failure of anchor bolt and cable anchoring effect, and insufficient adaptability of grouting parameters for deep and shallow surrounding rock to fracture characteristics, this invention proposes a full-space anchoring and grouting coordinated control method for gradient damage of roadway surrounding rock. The following will describe the device structure and specific implementation of this invention in detail with reference to the accompanying drawings.
[0024] 1. Support Scheme Design: The support scheme is designed based on the tunnel dimensions, surrounding rock mechanical properties, and ground stress conditions. In terms of support element arrangement, grouting sleeves 4 and anchor cables 1 are arranged alternately, located between two rows of traditional anchor bolts 3. The anchor bolts are connected by W-shaped steel strips 11. Both anchor bolts 3 and anchor cables 1 are end-anchored. A balanced support foundation is constructed through this reasonable layout, creating structural conditions for coordinated anchoring and grouting operations, while ensuring the stable support effect of the initial mechanical anchoring.
[0025] 2. Drilling Measurement of Rock Fracture Development Patterns and Determination of Grouting Casing Length: Exploratory boreholes were drilled at key locations on the roof (9) and sidewalls (6) of the roadway. Using modern exploration techniques such as borehole sights and resistivity detectors, the development patterns of rock fractures were measured on-site, particularly the relationship between fracture aperture and depth. Based on the measured distribution of rock fracture aperture, the lengths of the grouting casings (4) on the roof (9) and sidewalls (6) were determined. This ensured that the grout outlet (12) of the casing accurately corresponded to the target fracture area, providing a scientific basis for gradient grouting and avoiding the problem of ineffective reinforcement due to blind reinforcement.
[0026] 3. Grouting sleeve installation: The shallow grouting pipe with rubber sealing sleeve 5 is sleeved on the end of the anchor rod 3 or anchor cable 1. The anchor rod cable is made capable of grouting through the grouting sleeve 4. Then it is inserted into the borehole. Rubber gasket 2 and trays 8 and 10 are installed on the outside and pre-tightened by tightening the nut or tightening the lock. The rubber sealing sleeve 5 is tightly fitted to the end wall of the borehole. It not only prevents grout leakage during the grouting process through reliable sealing, but also enhances the shear resistance of the end of the anchor rod cable with the sleeve structure, making up for the defect of traditional support end failure due to shear displacement.
[0027] 4. Deep and shallow grouting: Grouting is carried out through the lateral external interface 13 of the grouting pipe. For shallow grouting, a shorter casing is used and ordinary cement is injected. For deep grouting, a longer casing is used and ultrafine cement is injected. When the grout overflows from the surrounding rock, the grouting is stopped based on the monitoring results of the acoustic wave or resistivity sensor. This ensures that the shallow large-aperture fractures are fully filled and that the deep micro-fractures are deeply penetrated. At the same time, the anchor-grouting collaborative mode simplifies the process and improves construction efficiency.
[0028] 5. Dynamic Monitoring and Supplementary Grouting of Surrounding Rock Fractals: Fiber optic fracture sensors, microseismic monitoring probes, and anchor cable stress sensors are installed near the grouting casings on the top and sides. All sensors are connected to a ground monitoring terminal via an IoT module to achieve real-time online monitoring of surrounding rock fractures, ground stress, and anchoring force. Quantitative alarm thresholds are set, such as: when the fracture opening increases by ≥0.5mm from the initial value, the anchor cable stress decreases by ≥10% from the initial value, or the frequency of surrounding rock microseismic events is ≥5 times / h, supplementary grouting is automatically triggered. Based on the monitoring data, the corresponding casing length, grout type, and grouting pressure are matched to perform local adaptive gradient grouting. Ultimately, a full-space support structure with coordinated anchor and cable bearing and shallow-deep gradient grouting is constructed, effectively controlling the gradient damage of the surrounding rock and improving the reliability and stability of the support system.
Claims
1. A method for coordinated control of gradient failure of surrounding rock in roadways using full-space anchoring and injection, characterized in that... A grouting sleeve is added to the end of the anchor cable, with a grouting port connected to the side of the sleeve. This overcomes the bottleneck of traditional anchoring and grouting not being able to be carried out simultaneously, achieving coordinated anchoring and grouting. Based on the gradient distribution characteristics of the surrounding rock fissure opening, the grouting sleeve is designed with different lengths to achieve gradient grouting at shallow and deep depths. Ordinary cement grout is injected into the shallow surrounding rock, while ultrafine cement is injected into the deep surrounding rock. Furthermore, the grouting sleeve can increase the shear strength of the anchor cable, preventing shear failure at the end. Specific process steps: (a) The support scheme is designed according to the tunnel size, surrounding rock mechanical properties and ground stress. The shallow and deep grouting casing and anchor cable are arranged at intervals and located in the middle of two rows of traditional anchor bolt support. Both anchor bolts and anchor cables are end anchored. (b) Drilling measurements of the development pattern of fissures in the surrounding rock of the roadway and determination of the length of the grouting casing: Drill holes of a certain depth in the center of the roof and the middle of the two sides of the roadway. Use a borehole sight and a resistivity detector to measure the distribution pattern of the fissure gradient in the roof and the two sides on site. Based on the measured distribution pattern of the fissure opening in the surrounding rock, determine the length of the grouting casing in the roof and the two sides. (c) Grouting sleeve installation: Sleeve the shallow grouting sleeve with rubber sealing sleeve onto the end of the anchor rod or anchor cable, then insert it into the drill hole, install a rubber washer at the end of the grouting sleeve, install a tray on the outside and apply pre-tightening force to tighten the nut or tighten the lock, and apply a certain pre-tightening force. (d) Deep and shallow grouting: Grouting is carried out through the side outward interface of the grouting pipe. For shallow grouting, a shorter casing is used and ordinary cement is injected. For deep grouting, a longer casing is used and ultrafine cement is injected. Grouting is stopped when the grout overflows from the surrounding rock. (e) Dynamic monitoring and supplementary grouting of surrounding rock fissures: Dynamic monitoring of surrounding rock fissures in boreholes. When the surrounding rock fissures are further developed due to mining, local supplementary gradient grouting is carried out to construct a full-space support structure with anchor bolt and cable synergistic bearing and shallow and deep gradient grouting, so as to achieve effective control of the gradient damage of surrounding rock.
2. The method for coordinated control of gradient failure of surrounding rock in roadways using full-space anchoring and injection, as described in claim 1, is characterized in that... The anchor bolt spacing is 0.8m~1.2m, the anchor bolt row spacing is 0.8m~1.0m, the anchor bolt length is 2.0m~2.4m, the anchor cable spacing is 0.8m~1.2m, the anchor cable row spacing is 1.6m~2.0m, and the anchor cable length is not less than 5.0m.
3. The method for coordinated control of gradient failure of surrounding rock in roadways using full-space anchoring and injection, as described in claim 1, is characterized in that... Shallow grouting sleeves are placed at the ends of the anchor bolts, with a length of 0.4m to 0.6m. Deep grouting sleeves are placed at the ends of the anchor cables, with a length of 1.0m to 2.0m and a diameter 6mm to 10mm larger than the diameter of the anchor bolt or anchor cable.
4. The method for coordinated control of gradient failure of surrounding rock in roadways using full-space anchoring and injection, as described in claim 1, is characterized in that... The end of the grouting sleeve is sealed with a rubber sleeve. The sealing rubber sleeve has a tapered design and its inner diameter is tightly matched with the grouting sleeve. The diameter of the thicker end is 5mm to 10mm larger than the diameter of the drill hole to ensure the sealing effect.
5. The method for coordinated control of gradient failure of surrounding rock in roadways using full-space anchoring and injection, as described in claim 1, is characterized in that... The shallow grouting pressure is 1.5MPa~2.0MPa, and the deep grouting pressure is 3.0MPa~4.0MPa. Grouting should be stopped when the grout overflows.
6. The method for coordinated control of gradient failure of surrounding rock in roadways using full-space anchoring and injection, as described in claim 1, is characterized in that... A rubber gasket is installed at the outer end of the grouting sleeve. The diameter of the opening in the middle of the rubber gasket is equal to the diameter of the anchor rod or anchor cable. The outer diameter of the rubber gasket is 30mm~50mm larger than the diameter of the end of the grouting sleeve to prevent grout leakage at the end.
7. The method for coordinated control of gradient failure of surrounding rock in roadways using full-space anchoring and injection, as described in claim 1, is characterized in that... Breaking through the bottleneck of traditional anchoring and grouting not being able to be carried out simultaneously, this method achieves coordinated anchoring and grouting, with the anchor rods applying a preload of not less than 60kN and the anchor cables applying a preload of not less than 150kN.