An anti-corrosion anchor rod and an anchoring method suitable for a corrosive stratum tunnel

Abstract

The present application belongs to the technical field of tunnel anchoring. The purpose is to provide a kind of anticorrosive anchor rod and anchoring method suitable for corrosion stratum tunnel, which has good corrosion resistance, pressure self-adaptability, can predict service life and improve anchoring effect. The technical scheme is as follows: a kind of anticorrosive anchor rod suitable for corrosion stratum tunnel, comprising: a hollow rod body; an expanded rubber sleeve sleeved outside the rod body; a double-cavity grouting pipe sleeved inside the rod body; a conical disperser with multiple slurry guide grooves; a self-control backflow valve fixed at the inlet end of the double-cavity grouting pipe; the double-cavity grouting pipe comprises a main grouting cavity and a pressure monitoring cavity arranged side by side, the inlet ends of the main grouting cavity and the pressure monitoring cavity are connected with an external grouting device through the self-control backflow valve, the outlet end of the main grouting cavity is communicated with the conical disperser, a piezoresistive pressure sensor is arranged in the pressure monitoring cavity, and the piezoresistive pressure sensor is electrically connected with the self-control backflow valve. The present application is used for anchoring of corrosion stratum tunnel.

Description

Technical Field

[0001] This invention relates to an anti-corrosion anchor rod and anchoring method suitable for tunnels in corrosive strata, belonging to the field of tunnel anchoring technology. Background Technology

[0002] In the field of tunnel engineering, especially in corrosive strata, rock bolts are widely used as an important support structure for the reinforcement and stabilization of tunnel surrounding rock. However, due to the characteristics of highly corrosive strata, complex geological structures, and high ground stress, traditional rock bolt systems face significant performance degradation during long-term service, leading to a decline in support effectiveness and even inducing safety hazards in tunnel structures.

[0003] Existing technologies for anti-corrosion anchor design and application have shortcomings such as insufficient anti-corrosion performance, difficulty in coping with complex corrosive environments, lack of pressure adaptability in grouting processes, limited construction efficiency and effectiveness, and lack of ability to perceive corrosive environments and predict service life.

[0004] In summary, existing anti-corrosion anchor technologies are insufficient to meet the long-term stability and safety requirements of tunnel support under complex geological conditions. Therefore, there is an urgent need to develop an anti-corrosion anchor that integrates triple dynamic sealing, pressure-adaptive grouting, and corrosion environment sensing and life prediction to improve the safety and durability of tunnel engineering in extreme geological environments. Summary of the Invention

[0005] To address the shortcomings of existing technologies, the present invention aims to provide an anti-corrosion anchor rod and anchoring method suitable for tunnels in corrosive strata. It has excellent anti-corrosion performance, pressure adaptability, predictable service life, and improves construction efficiency and anchoring effect.

[0006] To achieve the above objectives, the present invention adopts the following technical solution: an anti-corrosion anchor suitable for tunnels in corrosive strata, comprising: The rod body is hollow; An expansion rubber sleeve is fitted onto the outside of the rod. The outer circumferential surface of the expansion rubber sleeve is provided with a plurality of corrugated protrusions that surround it circumferentially and are spaced apart along the axial direction. A double-cavity grouting pipe, wherein the double-cavity grouting pipe is fitted inside the rod body and arranged along the axial direction of the rod body; A conical disperser, wherein the conical disperser is a hollow cone with multiple through slurry guide grooves distributed on the conical surface, the conical disperser is coaxially arranged with the rod body, and the large-diameter end is fixed to one end of the rod body; A self-controlled reflux valve is fixed at the inlet end of the dual-chamber grouting pipe; The dual-cavity grouting pipe includes a main grouting cavity and a pressure monitoring cavity arranged in parallel. The inlet ends of the main grouting cavity and the pressure monitoring cavity are connected to an external grouting device through a self-controlled reflux valve. The outlet end of the main grouting cavity is connected to a conical disperser. The pressure monitoring cavity is a cavity with a remotely closed end, and a piezoresistive pressure sensor is installed inside it. The piezoresistive pressure sensor is electrically connected to the self-controlled reflux valve.

[0007] Preferably, the surface of the rod is coated with a zinc-chromium coating as a sacrificial anode protection layer.

[0008] Preferably, the corrugated protrusions extend radially beyond the surface of the expansion rubber sleeve, with a height of 1.5-2.5 mm.

[0009] Preferably, the apex angle of the conical disperser is 30°-60°, the wall thickness is 2-3mm, the diameter of the large diameter end is 1.3 to 1.8 times the diameter of the rod body, the slurry guide channel is set along the generatrix on the conical surface of the conical disperser, and a layer of polytetrafluoroethylene nano-hydrophobic coating is sprayed on the inner wall of the slurry guide channel.

[0010] Preferably, the self-controlled reflux valve is equipped with a PID control chip, which is used to control the opening and closing of the pressure relief hole of the self-controlled reflux valve and the grouting speed of the external grouting device. Its signal input terminal is electrically connected to the piezoresistive pressure sensor.

[0011] Preferably, it also includes at least two sensor interfaces, a chloride ion concentration sensor and a constant current corrosion rate meter. All sensor interfaces are set on the outer surface of the rod and distributed on both sides of the expansion rubber sleeve. The chloride ion concentration sensor and the constant current corrosion rate meter are each fixed on one sensor interface.

[0012] An anchoring method suitable for tunnels in corrosive strata includes the following steps: S1. The anchor bolts are selected from the above-mentioned anti-corrosion anchor bolts suitable for tunnels in corrosive strata, and the grouting slurry is selected from microcapsule anti-corrosion slurry; S2. Drill anchor bolt holes in the tunnel cross section according to the design requirements and clean the rock debris inside the holes; S3. Insert the anti-corrosion anchor bolt suitable for tunnels in corrosive strata into the anchor bolt hole, so that the expansion rubber sleeve is located in the middle section of the anchor bolt hole, and connect the external grouting device to the self-controlled backflow valve. S4. Start the external grouting device to perform grouting. During the grouting process, the self-controlled reflux valve automatically adjusts the grouting pressure and flow rate according to the pressure data collected by the piezoresistive pressure sensor, so that the microcapsule anti-corrosion grout enters the cone-shaped disperser through the main grouting chamber and diffuses in an umbrella shape through the grout guide channel to fill the surrounding rock fissures. S5. After grouting is completed, shut down the external grouting device, remove the grouting pipeline, and clean up the construction site; S6. During the service life of the anchor bolt, corrosion environment data are collected in real time using a chloride ion concentration sensor and a constant-current corrosion rate meter to calculate the remaining service life of the anchor bolt, i.e., the predicted remaining service life of the anchor bolt: S7. When the calculated remaining service life of the anchor bolt is lower than the design safety threshold, an early warning signal shall be issued, and corresponding maintenance measures or replacement plans shall be taken according to the warning level. S8. Regularly assess the service status of the anchor bolts, and input the collected corrosion data and remaining life prediction results into the tunnel health monitoring system to provide data support for the safe operation and maintenance of the tunnel throughout its entire life cycle.

[0013] Preferably, in S1, the microcapsule anticorrosive slurry comprises: a sulfoaluminate cement matrix and epoxy resin curing agent microcapsules, wherein the epoxy resin curing agent microcapsules are formed by encapsulating the epoxy resin curing agent in the microcapsule shell using microcapsule granulation technology; The weight ratio of sulfoaluminate cement matrix to epoxy resin curing agent microcapsules is 95-97:3-5.

[0014] Preferably, in step S4, during the grouting process, the PID control chip inside the self-controlled reflux valve calculates the pressure error based on the preset target grouting pressure and the actual pressure collected by the piezoresistive pressure sensor, and adjusts the output control signal. When the actual pressure is higher than the safety threshold, the control signal output by the PID control chip drives the self-controlled reflux valve to open the pressure relief hole to release excess pressure, and at the same time drives the external grouting device to slow down the grouting speed. When the actual pressure is lower than the set range, the control signal output by the PID control chip drives the self-controlled reflux valve to close the pressure relief hole. The preset PID control algorithm in the PID control chip is as follows: Where: u(t) is the control output; e(t) is the pressure error; K p K is the proportionality coefficient. i K is the integral coefficient; d is the differential coefficient; t is time, indicating time t.

[0015] Preferably, in step S6, the formula for calculating the remaining service life of the anchor bolt is: Where: L rem C represents the remaining service life of the anchor bolt. Cl- The chloride ion concentration is obtained from a chloride ion concentration sensor; ε corr α represents the corrosion rate, obtained from a constant-current corrosion rate meter; α is the formation correction factor; β is the environmental correction factor; t is time; and d is the differential sign.

[0016] Compared with the prior art, the present invention has the following beneficial effects.

[0017] 1. In this invention, the surface of the rod is coated with zinc-chromium. Through the sacrificial anode mechanism, the zinc phase preferentially corrodes and forms a protective potential, which effectively reduces the corrosion rate of the steel and significantly extends the service life of the rod.

[0018] 2. In this invention, the expansion rubber sleeve set in the middle section of the rod can expand rapidly when it encounters groundwater, actively filling and sealing the gap between the rod and the surrounding rock, greatly reducing the risk of groundwater leakage.

[0019] 3. In this invention, the dual-cavity grouting pipe and the self-controlled reflux valve ensure that the grouting slurry can be continuously injected and effectively fill the cracks, and also prevent abnormal fluctuations in grouting pressure from adversely affecting the uniformity of grouting slurry distribution and anchoring effect.

[0020] 4. In this invention, the conical disperser guides the grout to diffuse directionally in the surrounding rock fissures, enabling the grout to diffuse directionally and effectively fill the fissures and improve the overall bonding performance between the anchor bolt and the surrounding rock.

[0021] 5. In this invention, a chloride ion concentration sensor and a constant current corrosion rate meter are connected through a sensor interface, which can monitor the surrounding environment in real time and predict the remaining life of the anchor bolt.

[0022] 6. In this invention, the grouting slurry uses microcapsule anti-corrosion slurry. The microcapsules exist for a long time after the slurry is cured. When the crack extends to the location of the microcapsule, the stress concentration causes the microcapsule to rupture rapidly and release the epoxy resin curing agent, thereby achieving active chemical repair of the crack and ensuring the long-term structural stability and integrity of the slurry.

[0023] This invention effectively improves the corrosion resistance and reliability of anchor bolts in harsh corrosive environments through the synergistic operation of multiple systems, achieving long-term corrosion prevention and efficient protection. Attached Figure Description

[0024] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the accompanying drawings used in the embodiments will be briefly introduced below.

[0025] Figure 1 This is a schematic diagram of the anti-corrosion anchor rod applicable to tunnels in corrosive strata in this invention.

[0026] Figure 2 This is a schematic cross-sectional view of the anti-corrosion anchor bolts suitable for tunnels in corrosive strata, as described in this invention, arranged inside the tunnel.

[0027] Figure 3 This is a schematic diagram of grouting control for anti-corrosion anchor bolts applicable to tunnels in corrosive strata in this invention.

[0028] Figure 4 This is a schematic diagram of the structure of the microcapsule anti-corrosion slurry in this invention.

[0029] In the diagram: 1 is the rod body, 101 is the zinc-chromium coating, 2 is the expansion rubber sleeve, 201 is the corrugated protrusion, 3 is the dual-cavity grouting pipe, 301 is the main grouting cavity, 302 is the pressure monitoring cavity, 303 is the piezoresistive pressure sensor, 4 is the conical disperser, 401 is the slurry guide channel, 5 is the self-controlled reflux valve, 501 is the PID control chip, 6 is the external grouting device, 7 is the sensor interface, 8 is the microcapsule anti-corrosion slurry, 801 is the sulfoaluminate cement matrix, 802 is the microcapsule shell, and 803 is the epoxy resin curing agent. Detailed Implementation

[0030] The technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other implementation methods obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0031] The present invention provides the following embodiments.

[0032] like Figure 1 As shown, the present invention provides an anti-corrosion anchor suitable for tunnels in corrosive strata, comprising: Rod 1, wherein rod 1 is hollow; An expansion rubber sleeve 2 is fitted over the rod body 1. The outer circumferential surface of the expansion rubber sleeve 2 is provided with a plurality of corrugated protrusions 201 that surround it circumferentially and are spaced apart along the axial direction. A double-cavity grouting pipe 3 is fitted inside the rod body 1 and arranged along the axial direction of the rod body 1. The conical disperser 4 is a hollow cone with multiple through-flow slurry guide grooves 401 distributed on its conical surface. The conical disperser 4 is coaxially arranged with the rod body 1, and its large-diameter end is fixed to one end of the rod body 1. The diameter of the large-diameter end of the conical disperser 4 is 1.3 to 1.8 times the diameter of the rod body 1. During grouting, after the grout flows out from the double-cavity grouting pipe inside the rod body, it encounters the larger-diameter conical disperser and can better diffuse to the surrounding area, forming an umbrella-shaped distribution, thereby more effectively filling the surrounding rock fissures. Self-controlled reflux valve 5, the self-controlled reflux valve 5 is fixed at the inlet end of the double-chamber grouting pipe 3; The dual-cavity grouting pipe 3 includes a main grouting cavity 301 and a pressure monitoring cavity 302 arranged in parallel. The inlet ends of the main grouting cavity 301 and the pressure monitoring cavity 302 are connected to the external grouting device 6 through a self-controlled reflux valve 5. The outlet end of the main grouting cavity 301 is connected to the conical disperser 4. The pressure monitoring cavity 302 is a cavity with a remotely closed end, and a piezoresistive pressure sensor 303 is installed inside it. The piezoresistive pressure sensor 303 is electrically connected to the self-controlled reflux valve 5.

[0033] In this invention, the expanding rubber sleeve 2 is set in the middle section of the rod body 1 and is made of a composite material of butyl rubber and superabsorbent resin. When it encounters groundwater, it expands rapidly and fills the gap between the rod body 1 and the surrounding rock, achieving efficient physical sealing and greatly reducing the risk of groundwater leakage. The corrugated protrusion 201 can form an effective mechanical interlock with the cracks in the surrounding rock, improving the shear strength and sealing performance of the interface.

[0034] In this invention, the main grouting chamber 301 serves as a dedicated channel for conveying the grout, ensuring that the grout is smoothly transmitted along the inside of the anchor bolt to the bottom of the hole and various crack areas. A high-sensitivity piezoresistive pressure sensor 303 installed inside the pressure monitoring chamber 302 continuously collects real-time pressure data within the pipeline. During the grouting process, the piezoresistive pressure sensor 303 transmits the collected pressure signal to the self-controlled return valve 5 in real time.

[0035] The surface of the rod 1 is coated with a zinc-chromium coating 101 as a sacrificial anode protective layer. The zinc-chromium coating has a zinc:chromium ratio of 7:3, which forms an electrochemical protection for the rod steel through a sacrificial anode mechanism.

[0036] The corrugated protrusion 201 protrudes radially from the surface of the expansion rubber sleeve 2, with a height of 1.5-2.5mm.

[0037] The cone-shaped disperser 4 has a apex angle of 30°-60° and a wall thickness of 2-3mm. The slurry guide channel 401 is set along the generatrix on the conical surface of the cone-shaped disperser 4, so that the grouting slurry diffuses in an umbrella-like direction. The inner wall of the slurry guide channel 401 is coated with a layer of polytetrafluoroethylene nano-hydrophobic coating to block the corrosion of the channel wall by corrosive media, so that the grouting slurry can diffuse and fill the cracks evenly and effectively, improve the micro-crack filling efficiency, and effectively improve the overall bonding performance between the anchor bolt and the surrounding rock.

[0038] The self-regulating reflux valve 5 is internally equipped with a PID control chip 501. The PID control chip 501 is used to control the opening and closing of the pressure relief hole of the self-regulating reflux valve 5 and the grouting speed of the external grouting device 6. Its signal input terminal is electrically connected to the piezoresistive pressure sensor 303. The PID control chip 501 is electrically connected to the self-regulating reflux valve 5 and the external grouting device 6 or wirelessly connected.

[0039] The PID control chip 501 can intelligently control the self-controlled reflux valve 5 to open the pressure relief hole to release excess pressure and drive the external grouting device 6 to slow down the grouting speed to prevent grout from gushing or overflowing.

[0040] The present invention provides an anti-corrosion anchor rod suitable for tunnels in corrosive strata, which also includes at least two sensor interfaces 7, a chloride ion concentration sensor and a constant current corrosion rate meter. All sensor interfaces 7 are set on the outer surface of the rod body 1 and distributed on both sides of the expansion rubber sleeve 2. The chloride ion concentration sensor and the constant current corrosion rate meter are each fixed on one sensor interface 7.

[0041] During the service life of anchor bolts, chloride ion concentration sensors and constant-current corrosion rate meters can monitor their surrounding environment in real time. The chloride ion concentration sensor monitors the concentration of chloride ions that have a significant impact on steel corrosion within the soil and rock mass; the constant-current corrosion rate meter accurately measures the amount of metal loss per unit area of ​​the reinforcing steel surface per unit time by controlling the electrode potential to remain constant, i.e., the corrosion rate. All collected data can be transmitted via RS485 bus. Based on the collected chloride ion concentration and corrosion rate data, combined with influencing factors under different geological conditions, a prediction model for the remaining service life of the anchor bolts can be constructed to predict their remaining lifespan.

[0042] like Figure 2 , Figure 3 As shown, the present invention provides an anchoring method for tunnels in corrosive strata, comprising the following steps: S1. The anchor bolts are selected from the above-mentioned anti-corrosion anchor bolts suitable for tunnels in corrosive strata, and the grouting slurry is selected from microcapsule anti-corrosion slurry 8; S2. Drill anchor bolt holes in the tunnel cross section according to the design requirements and clean the rock debris inside the holes; S3. Insert the anti-corrosion anchor bolt suitable for tunnels in corrosive strata into the anchor bolt hole, so that the expansion rubber sleeve 2 is located in the middle section of the anchor bolt hole, and connect the external grouting device 6 to the self-controlled backflow valve 5. S4. Start the external grouting device 6 to perform grouting. During the grouting process, the self-controlled reflux valve 5 automatically adjusts the grouting pressure and flow rate according to the pressure data collected by the piezoresistive pressure sensor 303, so that the microcapsule anti-corrosion grout 8 enters the cone-shaped disperser 4 through the main grouting chamber 301 and diffuses in an umbrella shape through the grout guide channel 401 to fill the surrounding rock fissures. S5. After grouting is completed, shut down the external grouting device 6, remove the grouting pipeline, and clean up the construction site; S6. During the service life of the anchor bolt, corrosion environment data are collected in real time using a chloride ion concentration sensor and a constant-current corrosion rate meter to calculate the remaining service life of the anchor bolt, i.e., the predicted remaining service life of the anchor bolt: S7. When the calculated remaining service life of the anchor bolt is lower than the design safety threshold, an early warning signal shall be issued, and corresponding maintenance measures or replacement plans shall be taken according to the warning level. S8. Regularly assess the service status of the anchor bolts, and input the collected corrosion data and remaining life prediction results into the tunnel health monitoring system to provide data support for the safe operation and maintenance of the tunnel throughout its entire life cycle.

[0043] like Figure 4 As shown, in S1, the microcapsule anticorrosive slurry 8 includes: sulfoaluminate cement matrix 801 and epoxy resin curing agent microcapsules. The epoxy resin curing agent microcapsules are made by encapsulating epoxy resin curing agent 803 in the microcapsule shell 802 using microcapsule granulation technology. The weight ratio of sulfoaluminate cement matrix 801 to epoxy resin curing agent microcapsules is 95-97:3-5.

[0044] The microcapsule shell 802 is made of polyurethane-nano SiO2 composite film.

[0045] In S4, during the grouting process, the PID control chip 501 inside the self-controlled reflux valve 5 calculates the pressure error based on the preset target grouting pressure and the actual pressure collected by the piezoresistive pressure sensor 303, and adjusts the output control signal. When the actual pressure is higher than the safety threshold, the control signal output by the PID control chip 501 drives the self-controlled reflux valve 5 to open the pressure relief hole to release the excess pressure, and at the same time drives the external grouting device 6 to slow down the grouting speed. When the actual pressure is lower than the set range, the control signal output by the PID control chip 501 drives the self-controlled reflux valve 5 to close the pressure relief hole. The preset PID control algorithm in the PID control chip 501 is as follows: Where: u(t) is the control output; e(t) is the pressure error; K p K is the proportionality coefficient. i K is the integral coefficient; d is the differential coefficient; t is time, indicating time t.

[0046] The self-controlled reflux valve 5 and the PID control chip 501 ensure that the grouting slurry can be continuously injected and effectively fill the cracks, and prevent abnormal fluctuations in grouting pressure from adversely affecting the uniformity of grouting slurry distribution and anchoring effect.

[0047] In step S6, the formula for calculating the remaining service life of the anchor bolt is: Where: L rem C represents the remaining service life of the anchor bolt. Cl-The chloride ion concentration is obtained from a chloride ion concentration sensor; ε corr α represents the corrosion rate, obtained from a constant-current corrosion rate meter; α is the formation correction factor; β is the environmental correction factor; t is time; and d is the differential sign.

[0048] The above description is merely a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in the present invention should be included within the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be determined by the scope of the claims.

Claims

1. A corrosion-resistant anchor bolt suitable for tunnels in corrosive strata, characterized in that, include: Rod (1), the rod (1) is hollow; An expansion rubber sleeve (2) is fitted over the rod body (1). The outer circumferential surface of the expansion rubber sleeve (2) is provided with a plurality of corrugated protrusions (201) that surround its circumference and are spaced apart along the axial direction. A double-cavity grouting pipe (3) is fitted inside the rod body (1) and arranged along the axial direction of the rod body (1); The conical disperser (4) is a hollow cone with multiple through slurry guide channels (401) distributed on the conical surface. The conical disperser (4) is coaxially arranged with the rod (1), and the large diameter end is fixed to one end of the rod (1). The slurry guide channels (401) are arranged along the generatrix on the conical surface of the conical disperser (4). Self-controlled reflux valve (5), the self-controlled reflux valve (5) is fixed at the inlet end of the double-chamber grouting pipe (3); The dual-cavity grouting pipe (3) includes a main grouting cavity (301) and a pressure monitoring cavity (302) arranged in parallel. The inlet ends of the main grouting cavity (301) and the pressure monitoring cavity (302) are connected to an external grouting device (6) through a self-controlled reflux valve (5). The outlet end of the main grouting cavity (301) is connected to a conical disperser (4). The pressure monitoring cavity (302) is a cavity with a remotely closed end, and a piezoresistive pressure sensor (303) is installed inside it. The piezoresistive pressure sensor (303) is electrically connected to the self-controlled reflux valve (5). The self-controlled reflux valve (5) is equipped with a PID control chip (501). The PID control chip (501) is used to control the opening and closing of the pressure relief hole of the self-controlled reflux valve (5) and the grouting speed of the external grouting device (6). Its signal input terminal is electrically connected to the piezoresistive pressure sensor (303). It also includes at least two sensor interfaces (7), a chloride ion concentration sensor and a constant current corrosion rate meter. All sensor interfaces (7) are set on the outer surface of the rod body (1) and distributed on both sides of the expansion rubber sleeve (2). The chloride ion concentration sensor and the constant current corrosion rate meter are each fixed on a sensor interface (7).

2. The anti-corrosion anchor bolt suitable for tunnels in corrosive strata according to claim 1, characterized in that: The surface of the rod (1) is coated with a zinc-chromium coating (101) as a sacrificial anode protection layer.

3. A corrosion-resistant anchor bolt suitable for tunnels in corrosive strata according to claim 1 or 2, characterized in that: The corrugated protrusion (201) protrudes radially from the surface of the expansion rubber sleeve (2) with a height of 1.5-2.5 mm.

4. The anti-corrosion anchor bolt suitable for tunnels in corrosive strata according to claim 3, characterized in that: The cone-shaped disperser (4) has a apex angle of 30°-60° and a wall thickness of 2-3 mm. The diameter of the large diameter end is 1.3 to 1.8 times the diameter of the rod (1). A layer of polytetrafluoroethylene nano-hydrophobic coating is sprayed on the inner wall of the slurry guide channel (401).

5. An anchoring method suitable for tunnels in corrosive strata, characterized in that, Includes the following steps: S1. The anchor bolt is selected as the anti-corrosion anchor bolt suitable for tunnels in corrosive strata as described in claim 4, and the grouting slurry is selected as microcapsule anti-corrosion slurry (8). S2. Drill anchor bolt holes in the tunnel cross section according to the design requirements and clean the rock debris inside the holes; S3. Insert the anti-corrosion anchor rod suitable for tunnels in corrosive strata into the anchor rod hole, so that the expansion rubber sleeve (2) is located in the middle section of the anchor rod hole, and connect the external grouting device (6) to the self-controlled return valve (5). S4. Start the external grouting device (6) to perform grouting. During the grouting process, the self-controlled reflux valve (5) automatically adjusts the grouting pressure and flow rate according to the pressure data collected by the piezoresistive pressure sensor (303), so that the microcapsule anti-corrosion slurry (8) enters the cone-shaped disperser (4) through the main grouting chamber (301) and diffuses in an umbrella shape through the slurry guide channel (401) to fill the surrounding rock fissures. S5. After grouting is completed, shut down the external grouting device (6), remove the grouting pipeline, and clean up the construction site; S6. During the service life of the anchor bolt, corrosion environment data are collected in real time using a chloride ion concentration sensor and a constant-current corrosion rate meter to calculate the remaining service life of the anchor bolt, i.e., the predicted remaining service life of the anchor bolt: S7. When the calculated remaining service life of the anchor bolt is lower than the design safety threshold, an early warning signal shall be issued, and corresponding maintenance measures or replacement plans shall be taken according to the warning level. S8. Regularly assess the service status of the anchor bolts, and input the collected corrosion data and remaining life prediction results into the tunnel health monitoring system to provide data support for the safe operation and maintenance of the tunnel throughout its entire life cycle.

6. The anchoring method for tunnels in corrosive strata according to claim 5, characterized in that: In S1, the microcapsule anticorrosive slurry (8) includes: sulfoaluminate cement matrix (801) and epoxy resin curing agent microcapsules. The epoxy resin curing agent microcapsules are made by encapsulating epoxy resin curing agent (803) in the microcapsule shell (802) using microcapsule granulation technology. The weight ratio of sulfoaluminate cement matrix (801) to epoxy resin curing agent microcapsules is 95-97:3-5.

7. An anchoring method for tunnels in corrosive strata according to claim 5 or 6, characterized in that: In S4, during the grouting process, the PID control chip (501) inside the self-controlled reflux valve (5) calculates the pressure error based on the preset target grouting pressure and the actual pressure collected by the piezoresistive pressure sensor (303), and adjusts the output control signal. When the actual pressure is higher than the safety threshold, the control signal output by the PID control chip (501) drives the self-controlled reflux valve (5) to open the pressure relief hole to release excess pressure, and at the same time drives the external grouting device (6) to slow down the grouting speed. When the actual pressure is lower than the set range, the control signal output by the PID control chip (501) drives the self-controlled reflux valve (5) to close the pressure relief hole. The preset PID control algorithm in the PID control chip (501) is as follows: Where: u(t) is the control output; e(t) is the pressure error; K p K is the proportionality coefficient. i K is the integral coefficient; d is the differential coefficient; t is time, indicating time t.

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