Reinforcing construction method in oversized hidden karst cave near tunnel

Abstract

The invention discloses a reinforcement construction method in a super-large hidden karst cave near a tunnel, which comprises the following steps: S1, drilling a drill hole leading to the karst cave in a structure on one side of the tunnel near the karst cave, and installing a reinforcement member through the drill hole to form a reinforcement structure for supporting a rock-soil body on the top surface of the karst cave; s2, after the anchoring end of the reinforcing component enters the karst cave, the anchoring end is tightly attached to the rock wall of the karst cave through structural adjustment, and a protective material is filled to seal a gap between the anchoring end and the rock wall; s3, a gap between the reinforcing component and the drill hole is reinforced, a monitoring device is installed to monitor the stress state of the reinforcing component, and the stability of the reinforcing structure in the tunnel operation period is ensured; according to the reinforcement construction method in the oversized hidden karst cave near the tunnel, the friction force between the claw-shaped component and the rock wall of the karst cave is further enhanced, the anti-sliding capacity of the anchoring end is remarkably improved, and the long-term stability of a supporting structure is ensured.

Description

Technical Field

[0001] The invention relates to the technical field of tunnel engineering and rock and soil reinforcement, and in particular to a method for reinforcing a super-large hidden karst cave near a tunnel. Background Art

[0002] In the field of tunnel construction and operation, the complexity of the geological environment is one of the important factors affecting the safety and stability of tunnel projects. Affected by the regional climate and groundwater, caves are often formed inside and underground the mountains, among which hidden caves are particularly common. Hidden caves refer to cavities or soluble landforms buried under the surface, usually formed by long-term erosion of groundwater. These caves have high permeability and large space, which may pose a potential threat to the construction and subsequent operation of tunnel projects.

[0003] Existing advanced geological prediction technologies have limitations in identifying and locating hidden caves, especially for hidden caves outside the tunnel section, which are difficult to detect and deal with comprehensively. Due to the inability to fully detect, after the tunnel is built and opened to traffic, if it experiences heavy rainfall in the rainy season, or due to train vibration and groundwater erosion, the rock and soil on the inner wall of the cave may become loose, peel off, or even collapse. These changes will affect the integrity of the rock mass, and thus have an adverse impact on the long-term operation and safety of the tunnel. At present, the disposal measures for caves mainly include backfilling, grouting, and strengthening support. During tunnel construction, caves are usually treated by backfilling with cave slag or synchronous grouting. However, when the tunnel has been built and the cave volume is large, the implementation of these traditional methods faces great difficulties and high costs. In addition, these methods may not be able to completely solve the stability problem of the cave during tunnel operation in actual operation. Summary of the invention

[0004] The purpose of the present invention is to provide a method for reinforcing a super-large hidden karst cave near a tunnel, so as to solve the problems existing in the prior art.

[0005] To achieve the above object, the present invention provides the following technical solution: a method for reinforcing a super-large hidden karst cave near a tunnel, the method comprising:

[0006] S1. Drilling a borehole leading to the cave on the structure on the side of the tunnel close to the cave, and installing a reinforcement component through the borehole to form a reinforcement structure for supporting the rock and soil mass on the top surface of the cave;

[0007] S2. After the anchor end of the reinforcement component enters the cave, the anchor end is closely attached to the cave rock wall through structural adjustment, and protective materials are filled to seal the gap between the anchor end and the rock wall;

[0008] S3. Reinforce the gap between the reinforced component and the drill hole, and install monitoring equipment to monitor the stress state of the reinforced component to ensure the stability of the reinforced structure during tunnel operation.

[0009] Preferably, the anchoring end comprises a claw-shaped member having a plurality of expandable branches, each branch being provided with a spring for controlling the claw-shaped member to change from a closed state to an open state and to cling to the cave rock wall.

[0010] Preferably, the outside of the claw-shaped member is provided with a waterproof, corrosion-resistant and highly elastic protective film, and when the claw-shaped member is opened, the protective film completely seals the gaps between each branch and the cave rock wall.

[0011] Preferably, the reinforcement treatment includes filling the gap between the reinforcement component and the drill hole by grouting, and the grouting material is a slurry with anti-seepage and anti-corrosion properties.

[0012] Preferably, the grouting is completed through a pre-installed grouting pipe, the exposed portion of the grouting pipe is connected to the drilling position, and the grouting port is sealed after the grouting is completed.

[0013] Preferably, the monitoring device includes a stress monitoring sensor installed on the reinforcement component, which is used to collect stress data of the reinforcement component in real time and transmit the data to the monitoring system for analysis.

[0014] Preferably, the direction and angle of the drilling hole are determined according to the location of the cave through geological exploration data before construction to ensure that the reinforcement component can effectively support the rock and soil on the top surface of the cave.

[0015] Preferably, when the claw-shaped member at the anchoring end is in an open state, the opening angles of the branches thereof are adjusted by the elastic force of a spring to adapt to different shapes of the cave rock wall.

[0016] Preferably, each branch surface of the claw-type member is provided with an anti-slip tooth structure to increase the contact stability between the claw-type member and the cave rock wall.

[0017] Preferably, the protective film is made of a high molecular polymer material, has high strength and durability, and can resist long-term erosion by groundwater.

[0018] It can be seen from the above technical solution that the present invention has the following beneficial effects:

[0019] The reinforcement construction method for the super-large hidden karst cave near the tunnel improves the overall stability of the karst cave area through scientific and reasonable reinforcement construction steps, providing important guarantee for the safe operation of the tunnel. The branches are opened and pressed against the karst cave rock wall by springs to form a stable support structure, which not only enhances the contact area between the anchor end and the karst cave rock wall, but also improves the reliability of the support effect. The waterproof, corrosion-resistant and highly elastic protective film completely seals the gap between the anchor end and the rock wall in the open state, effectively preventing the leakage of grouting materials and enhancing the durability of the anchor end. It is suitable for complex underground environments. By filling the gap between the reinforced components and the boreholes, the anti-seepage and anti-corrosion slurry further improves the overall strength and deformation resistance of the reinforced structure, adapting to long-term operation needs. Grouting operations are carried out through grouting pipes, which facilitates the precise control of the flow direction and amount of grouting materials during construction. After the grouting is completed, the grouting port is sealed to further prevent material loss or environmental pollution problems. The monitoring device collects data in real time. The stress data of the anchoring components is analyzed through the monitoring system, which provides a basis for the long-term status monitoring and maintenance of the karst cave area, helps to discover potential problems early and take countermeasures, and determines the design of the drilling direction and angle based on the geological exploration data to ensure that the reinforcement components can fully cover the support requirements of the rock and soil on the top surface of the karst cave, thereby improving the construction accuracy and effectiveness of the reinforcement structure. The opening angle of the claw-type component branch is adjusted by the spring to adapt to the karst cave rock wall of different forms, thereby enhancing the adaptability of the support system and providing a reliable technical solution for construction under complex geological conditions. By setting an anti-skid tooth pattern structure on the surface of the claw-type component, the friction between the claw-type component and the karst cave rock wall is further enhanced, which significantly improves the anti-skid ability of the anchor end and ensures the long-term stability of the support structure. By setting an anti-skid tooth pattern structure on the surface of the claw-type component, the friction between the claw-type component and the karst cave rock wall is further enhanced, which significantly improves the anti-skid ability of the anchor end and ensures the long-term stability of the support structure. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 is a flow chart of the method of the present invention;

[0021] Figure 2 The present invention is a layout diagram of the anchor cable support structure between the tunnel and the cave;

[0022] Figure 3 It is a schematic diagram of a claw-shaped member of an anchor cable of the present invention;

[0023] Figure 4 Another schematic diagram of the claw-shaped member of the anchor cable of the present invention;

[0024] Figure 5 It is a schematic diagram of the structure of the anchor cable of the present invention.

[0025] In the figure: 1. Claw-type component; 2. Spring; 3. Protective film; 4. Grouting pipe. DETAILED DESCRIPTION

[0026] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0027] like Figure 1-Figure 5 As shown, a method for reinforcing a super-large hidden karst cave near a tunnel comprises:

[0028] S1. Drilling a borehole leading to the cave on the structure on the side of the tunnel close to the cave, and installing a reinforcement component through the borehole to form a reinforcement structure for supporting the rock and soil mass on the top surface of the cave;

[0029] S2. After the anchor end of the reinforcement component enters the cave, the anchor end is closely attached to the cave rock wall through structural adjustment, and protective materials are filled to seal the gap between the anchor end and the rock wall;

[0030] S3. Reinforce the gap between the reinforced component and the drill hole, and install monitoring equipment to monitor the stress state of the reinforced component to ensure the stability of the reinforced structure during tunnel operation.

[0031] In this embodiment, the reinforcement components are directly applied to the rock and soil on the top of the cave by drilling holes, and the external force is transmitted to the stable rock wall, thereby dispersing and reducing the stress concentration that may be borne on the top of the cave, and avoiding the collapse of the rock and soil. The anchor end is in close contact with the rock wall of the cave and filled with protective materials to ensure the sealing and stability of the joint. The overall shear and tensile properties are further improved by processing the gap between the reinforcement components and the drilled holes. The real-time monitoring device provides long-term protection for the stability of the structure after construction. The reinforced structure can significantly improve the supporting capacity of the rock and soil on the top of the cave and prevent risks caused by geological instability in the tunnel area. Sealing treatment and gap reinforcement effectively avoid the influence of external factors on the reinforced structure, such as groundwater infiltration and chemical erosion. The real-time monitoring system ensures the structural stability of the tunnel during long-term operation and promptly detects and handles potential problems.

[0032] In a possible embodiment, the anchoring end includes a claw-type component 1, and the claw-type component 1 has a plurality of branches that can be opened. Each branch is provided with a spring 2 for controlling the claw-type component 1 to change from a closed state to an open state and to be close to the cave rock wall. Through the elastic force of the spring mechanism, the branches of the claw-type component can automatically open after entering the cave to ensure the tightness of the fit with the cave rock wall. The spring provides an independent adjustment force for each branch, so that it can flexibly adapt to rock walls of different shapes and avoid the problem of unstable installation caused by morphological differences during construction. A flexible anchoring method is provided to ensure the stability of the reinforced component. The design of the spring opening is highly adaptable and can adapt to complex cave shapes, reducing the workload of secondary adjustments. The contact area between the anchoring end and the cave rock wall is increased, and the overall support effect is enhanced.

[0033] In a possible embodiment, the outside of the claw-type member 1 is provided with a waterproof, corrosion-resistant and highly elastic protective film 3, and the protective film 3 completely seals the gaps between each branch and the cave rock wall when the claw-type member 1 is opened. The protective film 3 expands synchronously when the claw-type member is opened, and its high elasticity ensures that it can cover the gaps between all branches and the rock wall, thereby forming a continuous sealing layer. This sealing layer can prevent long-term damage to the reinforced structure by groundwater and corrosive substances. The sealing structure effectively prevents the influence of external environmental factors on the reinforced components and improves durability. It provides additional protection measures to avoid wear or displacement that may be caused by direct contact between the anchor end and the rock wall. It improves the overall environmental adaptability of the reinforcement and extends the service life of the reinforced structure.

[0034] In a possible embodiment, the reinforcement treatment includes filling the gap between the reinforcement member and the borehole by grouting, and the grouting material is a slurry with impermeability and corrosion resistance. By injecting a slurry of a specific ratio into the gap between the reinforcement member and the borehole, the slurry can diffuse and fill in the narrow gap, and finally solidify to form a filling layer with high strength and stability. The impermeability ensures that the filling layer can effectively block the infiltration of groundwater, while the corrosion resistance protects the reinforcement member and the borehole wall from chemical erosion. The connection strength and stability of the reinforcement member and the borehole are improved, and the risk of displacement or shear damage is reduced. By using impermeability and corrosion resistance slurry, the durability of the entire structure is enhanced, especially the adaptability in a wet or corrosive environment. The construction efficiency is optimized, and the grouting process is simple and easy to operate, which is suitable for complex geological conditions on site.

[0035] In a possible embodiment, the grouting is completed by a pre-installed grouting pipe 4, the exposed portion of which is connected to the drilling position, and the grouting port is sealed after the grouting is completed. The grouting pipe 4 serves as a conveying channel for the slurry, and its exposed portion is convenient for connection with the grouting equipment. During the construction process, the grouting amount and pressure are controlled to make the slurry evenly distributed in the gap between the reinforcement component and the borehole. After the grouting is completed, the sealing of the grouting port can prevent the slurry from flowing back or the intrusion of external pollutants. The use of the grouting pipe facilitates construction operations and can improve the efficiency and accuracy of grouting. Sealing the grouting port can further improve the integrity of the reinforcement treatment and avoid the impact of later environmental changes on the reinforced structure. The flexible grouting pipe design can adapt to the needs of drilling holes of different lengths and shapes.

[0036] In one possible implementation, the monitoring device includes a stress monitoring sensor installed on the reinforcement component, which is used to collect the stress data of the reinforcement component in real time and transmit the data to the monitoring system for analysis. The stress monitoring sensor uses precision measurement technology to sense the stress changes on the reinforcement component in real time, and transmits this data to the monitoring system in the form of a signal. The monitoring system can record, analyze and display the data to help construction personnel promptly grasp the stress state of the reinforcement component and evaluate the stability and safety of the structure. Real-time monitoring can effectively warn of possible structural problems and provide data support for maintenance and repair. Through long-term monitoring, a large amount of construction data can be accumulated to provide experience and parameter basis for similar projects. Digital management improves the accuracy and reliability of monitoring and reduces the workload of manual inspections.

[0037] In a possible implementation, the direction and angle of the borehole are determined according to the geological exploration data before construction based on the location of the cave to ensure that the reinforcement component can effectively support the rock and soil on the top surface of the cave. Through geological exploration means such as geological radar or drilling sampling, the spatial position, shape and rock and soil properties of the cave are obtained. According to these data, the direction and angle of the borehole are designed so that it can accurately penetrate the area on the top surface of the cave that needs to be supported, ensuring the uniformity and stability of the force of the reinforcement component. The drilling design guided by geological data improves the pertinence and effectiveness of the construction and reduces the possibility of invalid drilling. Accurate drilling positioning maximizes the support effect of the reinforced structure and helps to extend the service life of the reinforced structure. It reduces secondary drilling or rework that may be caused by construction errors and improves engineering efficiency.

[0038] In a possible implementation, when the claw-type member 1 at the anchoring end is in the open state, the opening angle of each branch thereof is adjusted by the elastic force of the spring 2 to adapt to the different shapes of the cave rock wall. The opening angle of the branches of the claw-type member 1 is adjusted by the elastic force of the spring 2, so that it can be automatically adjusted according to the shape of the cave rock wall to ensure that each branch can be in close contact with the rock wall. The elastic coefficient of the spring is optimized according to the strength of the rock wall and the anchoring requirements, which not only ensures the flexibility of the branch, but also ensures the stability of the support. The adaptive adjustment function significantly improves the anchoring effect of the claw-type member in complex terrain and reduces the support defects caused by the irregular shape of the rock wall. The spring adjustment provides a stable opening force, so that the claw-type member can maintain reliable fit in various environments. This design simplifies the anchoring construction process, eliminates the need for additional manual adjustment of the branch angle, and improves construction efficiency.

[0039] In a possible embodiment, each branch surface of the claw-type member 1 is provided with an anti-skid tooth pattern structure to increase the contact stability between the claw-type member 1 and the cave rock wall. The anti-skid tooth pattern structure on the branch surface of the claw-type member 1 increases the friction force by physical embedding when in contact with the rock wall, thereby improving the stability of the anchoring. The shape and arrangement of the tooth pattern are designed according to the material properties of the rock wall to maximize the anchoring effect and reduce the risk of slippage. The anti-skid tooth pattern enhances the shear resistance of the anchoring end and improves the overall deformation resistance of the structure. This design further reduces the risk of the claw-type member detaching from the rock wall due to uneven force, thereby improving construction safety. It reduces the reliance on external fixing measures and optimizes the construction process and cost.

[0040] In a possible implementation, the protective film 3 is made of a polymer material, has high strength and durability, and can resist long-term groundwater erosion. The protective film 3 is made of a polymer material, and provides excellent mechanical strength and durability through the polymer chain structure of the material. The material is waterproof and chemical-resistant, and can effectively resist the corrosive ions and microbial invasion in groundwater, ensuring that the protective film maintains stability and integrity in a complex underground environment for a long time. The polymer material enhances the service life of the protective film and reduces the cost of replacement and maintenance. The ability to resist groundwater erosion ensures that the sealing performance between the anchor end and the rock wall is long-term and effective. Provide an additional physical protection layer to prevent the external environment from causing mechanical damage to the anchor end.

[0041] Working process: Step 1: First, remove the secondary lining structure of the existing tunnel, find a good angle to drill holes on the side wall and arch bottom of the existing tunnel close to the cave until the top of the cave below, and drive anchor cables through the holes to form an anchor cable support structure between the existing tunnel and the cave top to support and reinforce the rock wall of the cave top.

[0042] Step 2: After the anchor cable is driven into the borehole and the anchor end passes through the borehole, the fastening head at the rear end of the anchor cable is tightened to apply force to the springs 2 on the branches of the claw-shaped member 1 at the anchor end, and the claw-shaped member (1) changes from a closed state during the drilling to an open state, and is closely attached to the cave rock wall; the protective film attached to the claw-shaped member 1 tightly wraps the gaps between the branches and the rock wall in an umbrella shape as the claw-shaped member 1 opens.

[0043] Step 3: Grout the gap between the anchor cable and the drill hole. After grouting reinforcement, reserve a space behind the steel gasket 5 at the anchor cable fastening end to install the anchor cable stress monitoring device to monitor the subsequent anchor cable stress state, and finally re-apply the secondary lining.

[0044] like Figure 2 As shown, there is a super large cave near the tunnel, and the cavity of the cave is generally high on the left and low on the right (in the direction of the line), narrow at the top and wide at the bottom. The reinforcement structure for the super large hidden cave is mainly an anchor cable support structure, which is located between the tunnel side wall and arch bottom and the cave top. Drilling operations are carried out from the existing tunnel side wall and arch bottom to the cave top below and the anchor cables are driven in.

[0045] like Figure 3 and Figure 4 As shown, the anchoring end of the anchor cable is a claw-shaped component 1, and there are springs 2 on each branch of the claw-shaped component 1. The claw-shaped component 1 is in a closed state when not under stress. When the anchoring section of the anchor cable passes through the drill hole, the tightening head is pulled to stress the spring 2, and the spring 2 controls each branch to spread out and cling to the cave rock wall to form a relatively stable support structure.

[0046] like Figure 3 and Figure 4 As shown, there is a protective film 3 on the outside of the claw-shaped member 1, which is made of a waterproof, corrosion-resistant and highly elastic material. When the claw-shaped member 1 is opened, the opened branches are completely wrapped inside and closely attached to the cave rock wall. The protective film 3 completely seals the gap between the anchor end and the cave rock wall to prevent subsequent grouting liquid from leaking.

[0047] like Figure 5 As shown, the anchor cable support structure includes an anchor cable anchoring end (claw-shaped member), an anchor cable free section, and an anchor cable fastening end (steel gasket and nut). The grouting treatment is carried out through a PE grouting pipe 4. After the anchor cable is installed, the PE pipe is inserted as a grouting pipe. The grouting pipe 4 is exposed about 10 cm. The steel gasket 5 is installed, and the nut 6 is locked before grouting.

[0048] Although embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present invention, and that the scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. A method for reinforcing a super-large hidden karst cave near a tunnel, characterized in that: The method comprises: S1. Drilling a borehole leading to the cave on the structure on the side of the tunnel close to the cave, and installing a reinforcement component through the borehole to form a reinforcement structure for supporting the rock and soil mass on the top surface of the cave; S2. After the anchor end of the reinforcement component enters the cave, the anchor end is closely attached to the cave rock wall through structural adjustment, and protective materials are filled to seal the gap between the anchor end and the rock wall; S3. Reinforce the gap between the reinforced component and the drill hole, and install monitoring equipment to monitor the stress state of the reinforced component to ensure the stability of the reinforced structure during tunnel operation.

2. The method for reinforcing a super-large hidden karst cave near a tunnel according to claim 1, characterized in that: The anchoring end comprises a claw-shaped component (1), wherein the claw-shaped component (1) has a plurality of branches that can be opened, and each branch is provided with a spring (2) for controlling the claw-shaped component (1) to change from a closed state to an open state and to closely adhere to the cave rock wall.

3. The method for reinforcing a super-large hidden karst cave near a tunnel according to claim 2 is characterized by: The outside of the claw-shaped component (1) is provided with a waterproof, corrosion-resistant and highly elastic protective film (3); when the claw-shaped component (1) is opened, the protective film (3) completely seals the gaps between each branch and the cave rock wall.

4. The method for reinforcing a super-large hidden karst cave near a tunnel according to claim 1 is characterized in that: The reinforcement treatment includes filling the gap between the reinforcement component and the drill hole by grouting, and the grouting material is a slurry with anti-seepage and anti-corrosion properties.

5. The method for reinforcing a super-large hidden karst cave near a tunnel according to claim 4 is characterized in that: The grouting is completed through a pre-installed grouting pipe (4), the exposed portion of the grouting pipe (4) is connected to the drilling position, and the grouting port is sealed after the grouting is completed.

6. The method for reinforcing a super-large hidden karst cave near a tunnel according to claim 1, characterized in that: The monitoring device includes a stress monitoring sensor installed on the reinforcement component, which is used to collect the stress data of the reinforcement component in real time and transmit the data to the monitoring system for analysis.

7. The method for reinforcing a super-large hidden karst cave near a tunnel according to claim 1, characterized in that: The direction and angle of the drilling hole are determined according to the location of the cave through geological exploration data before construction to ensure that the reinforcement components can effectively support the rock and soil on the top surface of the cave.

8. The method for reinforcing a super-large hidden karst cave near a tunnel according to claim 1, characterized in that: When the claw-shaped component (1) at the anchoring end is in an open state, the opening angles of the branches are adjusted by the elastic force of the spring (2) to adapt to different shapes of the cave rock wall.

9. The method for reinforcing a super-large hidden karst cave near a tunnel according to claim 8, characterized in that: Each branch surface of the claw-shaped component (1) is provided with an anti-slip tooth pattern structure, which is used to increase the contact stability between the claw-shaped component (1) and the cave rock wall.

10. The method for reinforcing a super-large hidden karst cave near a tunnel according to claim 3, characterized in that: The protective film (3) is made of high molecular polymer material, has high strength and durability, and can resist long-term erosion by groundwater.

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