Temporary support material and concrete lining maintenance method using it

Abstract

The present disclosure provides a temporary support material used for concrete lining maintenance, particularly for tunnel concrete lining maintenance where ground pressure is high, and a method for tunnel concrete lining maintenance using the said temporary support material that has excellent stability and can be similar to or exceed the mechanical strength of the initial tunnel concrete lining.

Description

Technology Field

[0001] The present disclosure provides a method for maintaining tunnel concrete lining efficiently and without additional damage by using temporary support materials. Background Technology

[0002] Recently, as there is a trend to construct roads and railways in deep underground tunnels for efficient layout and aesthetics, interest and demand for deep underground tunnel excavation construction are increasing.

[0003] Conventional tunnel construction methods are broadly divided into two main types: the New Austrian Tunneling Method (NATM) and the Shield-TBM (Shield Tunnel Boring Machine) method.

[0004] The above NATM process is a method of constructing a tunnel in which the ground surrounding the tunnel serves as the main support material, and additional support materials such as rebar, concrete, shotcrete, rock bolts, and steel supports are installed if necessary.

[0005] Therefore, although the above-mentioned NATM process can ensure stability and durability during construction by distributing the external forces of the excavated tunnel ground from the surrounding ground and additional support materials, there are problems such as slow construction speed, difficulty in construction in locations with weak ground, and additional costs incurred due to the installation of additional support materials.

[0006] The aforementioned Shield-TBM method is a construction technique in which concrete segments are installed on the walls of the excavated tunnel while excavating the ground with an excavation head. In other words, in the Shield-TBM, the installed concrete segments bear most of the external ground forces of the tunnel, and since the concrete lining formed by assembling the segments simultaneously with excavation acts as the primary support material, there is a disadvantage in that future repair work on the concrete lining is difficult.

[0007] As explained above, the main reason why repair work is difficult on tunnels constructed using the Shield-TBM method is that the concrete lining formed from concrete segments acts as the primary support material for the ground; therefore, when repairing the tunnel concrete lining, the damaged portion is removed, leaving the remaining lining unable to adequately support the external forces of the ground outside the tunnel.

[0008] Therefore, if the ground load applied to the removed damaged section of the tunnel concrete lining is not sufficiently supported prior to the removal of the damaged section, the sound section that was not damaged may be damaged, or in severe cases, the tunnel may collapse, making it impossible to guarantee the safety of the workers.

[0009] In other words, conventional tunnel concrete lining repairs must install temporary support materials to mitigate the deterioration of ground support performance caused by the removed damaged section. However, since conventional temporary support materials must be installed entirely to support the entire tunnel area corresponding to the removed damaged section according to the tunnel curvature, the construction period is delayed and construction costs are inevitably increased.

[0010] Furthermore, since the aforementioned conventional temporary support materials require a significant amount of time to install, their retrieval is cumbersome. Moreover, even if they are retrieved after construction is complete, they cannot be reused for repair work on tunnels with different excavation diameters; consequently, most of the retrieved materials are discarded, resulting in low economic efficiency and inevitably causing environmental pollution due to civil engineering waste.

[0011] The aforementioned conventional concrete lining repair causes many problems in the removal of damaged parts and repair methods, in addition to the issues arising from the removal of damaged parts of the concrete lining and the use of conventional temporary support materials described above.

[0012] The aforementioned conventional tunnel concrete lining repair involves removing damaged concrete using a hand breaker; however, this method requires a high level of skill from the operator, and the time required for the process varies depending on the operator's proficiency. In particular, if a low-skilled operator performs the repair, it is difficult to repair the tunnel concrete lining while maintaining its original strength, as it may further damage the reinforcing bars or intact, sound sections of the concrete lining.

[0013] In addition, the above-mentioned conventional tunnel concrete lining repair is used to repair and reinforce damaged sections removed by the shotcrete method when the cross-section of the tunnel cavity is not secured to the extent that conventional temporary support installation and repair work is difficult.

[0014] The above shotcrete method involves spraying concrete or mortar together with gas at high pressure, and has a fast construction speed. However, the above conventional shotcrete method inevitably requires preliminary steps such as cleaning the removed surface and preventing rebar corrosion before the shotcrete application. In particular, since it cannot be guaranteed that the tunnel concrete lining repaired by the above shotcrete method has been repaired with a high adhesion state to the boundary surface with the removed damaged part, there is a problem in that the repaired shotcrete easily delaminates due to external forces.

[0015] Therefore, there is a need for a new method for repairing temporary support materials and concrete linings to solve the problems of the aforementioned conventional temporary support materials and concrete lining repairs. The problem to be solved

[0016] One objective of the present disclosure is to provide a temporary support material capable of supporting a concrete lining even after the damaged portion is removed during the repair of a tunnel concrete lining.

[0017] One objective of the present disclosure is to provide a temporary support material that can be installed directly and optionally on a damaged section of a removed tunnel concrete lining.

[0018] One objective of the present disclosure is to provide a temporary support material that is easy to recover after the repair of a tunnel concrete lining is completed and can be reused in other tunnel concrete lining repair projects.

[0019] One objective of the present disclosure is to provide a temporary support material that can be installed directly and easily in a damaged section of tunnel concrete, even when the tunnel's internal cross-section is not sufficiently secured.

[0020] One objective of the present disclosure is to provide a method for maintaining a tunnel concrete lining in which there is no additional damage to the sound concrete portion and the embedded reinforcement, and the repaired concrete lining has the same or increased mechanical strength as the original concrete lining, and in particular, there is no spalling of the repaired concrete lining. means of solving the problem

[0021] The present disclosure provides a temporary support material inserted into a hollow section formed by cutting the boundary between a damaged section of a tunnel concrete lining requiring repair and a sound section of the tunnel concrete lining. The temporary support material may be of a hollow form composed of an exoskeleton and a hollow section, wherein a hydraulically adjustable inflatable member is disposed on the outer surface of the exoskeleton and a steel pipe member is disposed on the inner surface.

[0022] In one embodiment of the present disclosure, the temporary support material may have an exoskeleton portion having the same thickness at any height.

[0023] In one embodiment of the present disclosure, the temporary support material may have a structure in which the maximum diameter of the cross-section increases linearly in the vertical direction, and the exoskeleton may have an inclination of 5 to 40° in the vertical direction.

[0024] In one embodiment of the present disclosure, the temporary support member may be in the shape of a cone, having a circular cross-section in the vertical direction.

[0025] In one embodiment of the present disclosure, the hydraulic adjustable expandable member may have a hydraulic injection hole and a hydraulic hose arranged in the opposite direction to be inserted into the concave portion.

[0026] In one embodiment of the present disclosure, the steel pipe member may be formed from a material having a compressive strength of 20 MPa or more and an elastic modulus of 10 GPa or more as measured by ASTM D638.

[0027] In one embodiment of the present disclosure, the exoskeleton may have a thickness ratio of a hydraulic inflatable member and a steel pipe member before expansion of 1:1 to 1:5.

[0028] In one embodiment of the present disclosure, the temporary support material may reduce the stress generated in the vertical cross-section of the damaged concrete section removed during the repair process of the damaged section of the tunnel concrete lining to 0.5 times or less.

[0029] The present disclosure may provide a method for maintaining a tunnel concrete lining, comprising the steps of: cutting the boundary of a damaged portion of the tunnel concrete lining with a water jet to form a depression; inserting a temporary support material described above into the depression; cutting the damaged portion of the tunnel concrete lining with a water jet; repairing the cut damaged portion; recovering the temporary support material inserted into the depression; and repairing the depression.

[0030] In one embodiment of the present disclosure, the tunnel concrete lining maintenance method may involve expanding an expandable member of a conical steel support inserted into a concave portion to completely fix the inserted temporary support into the concave portion.

[0031] In one embodiment of the present disclosure, the tunnel concrete lining maintenance method may further include the step of detecting damage to the concrete lining using a non-destructive inspection device.

[0032] In one aspect of the present disclosure, the tunnel concrete lining maintenance method may further include the step of inspecting the repaired damaged portion and the repaired concave portion with a non-destructive inspection device. Effects of the invention

[0033] In one embodiment of the present disclosure, the temporary support material effectively relieves stress concentrated on the vertical cross-section of the damaged portion of the removed tunnel concrete lining, thereby allowing work to be performed while maintaining the structural stability of the tunnel for a long period even after the damaged portion is removed during tunnel concrete lining repair work, thus ensuring the safety of workers and enabling maintenance and repair to a strength similar to or greater than that of the initial concrete lining.

[0034] In one embodiment of the present disclosure, the temporary support material is not disposable but can be reused in other tunnel concrete lining repair works after recovery, thereby preventing environmental pollution caused by waste and reducing construction costs.

[0035] In one embodiment of the present disclosure, the method for repairing a tunnel concrete lining using the temporary support material prevents additional damage to the embedded reinforcement or undamaged sound parts due to stress concentration in the vertical cross-section of the damaged part of the removed tunnel concrete lining, so that the repaired tunnel concrete lining can be maintained and repaired for a long period with excellent durability.

[0036] The tunnel concrete lining maintenance method of the present disclosure does not cause a significant difference in construction speed depending on the skill level of the worker, and since there is little change in the physical properties of the repaired concrete lining, the tunnel concrete lining repaired as described above can maintain excellent durability for a long period.

[0037] Accordingly, the temporary support material according to one embodiment of the present disclosure can be continuously reused, maintains the structural stability of the tunnel with simple installation, and allows for repair work on the tunnel concrete lining.

[0038] In addition, the tunnel concrete lining maintenance method using the temporary support material described above offers excellent workability and allows the concrete lining to be maintained and repaired to mechanical properties suitable for long-term use at a low maintenance cost. Brief explanation of the drawing

[0039] FIG. 1 is a result of measuring the change in stress concentrated in the vertical cross-section of the damaged portion of the removed tunnel concrete lining, according to one embodiment of the present disclosure, by installing a temporary support material on the tunnel concrete lining. FIG. 2 shows the temporary support material according to one embodiment of the present disclosure. FIG. 3 shows the above-mentioned support material installed in the rear direction of the tunnel concrete lining according to one embodiment of the present disclosure. FIG. 4 is a simplified diagram of a tunnel concrete lining maintenance method according to one embodiment of the present disclosure. FIG. 5 illustrates the step of forming a depression in the tunnel concrete lining maintenance method according to one embodiment of the present disclosure. FIG. 6 illustrates the step of inserting a temporary support material into the formed depression in the tunnel concrete lining maintenance method according to one embodiment of the present disclosure. FIG. 7 illustrates, in a tunnel concrete lining maintenance method according to one embodiment of the present disclosure, a hydraulically adjustable expandable member of a temporary support inserted into a recess is expanded and fixed. FIG. 8 illustrates the step of cutting a damaged portion of a tunnel concrete lining with a water jet in a tunnel concrete lining maintenance method according to one embodiment of the present disclosure. FIG. 9 illustrates a step of repairing the cut damaged portion in the tunnel concrete lining maintenance method according to one aspect of the present disclosure. FIG. 10 illustrates a step of repairing the concave portion in the tunnel concrete lining maintenance method according to one embodiment of the present disclosure. Specific details for implementing the invention

[0040] Hereinafter, the temporary support material of the present disclosure and the tunnel concrete lining maintenance method using the same will be described.

[0041] The advantages and features of the present disclosure and the methods for achieving them will become clear by referring to the embodiments described in detail below. However, the present disclosure is not limited to the embodiments disclosed below but may be implemented in various different forms. These embodiments are provided merely to ensure that the disclosure of the present disclosure is complete and to fully inform those skilled in the art of the scope of the invention, and the present disclosure is defined only by the scope of the claims.

[0042] Unless otherwise defined, all terms used in this specification (including technical and scientific terms) may be used in a meaning that is commonly understood by those skilled in the art to which this disclosure pertains.

[0043] Unless otherwise specifically indicated, the singular form of a term used in this specification may be interpreted to include the plural form.

[0044] The numerical ranges used herein include lower and upper limits and all values ​​within the range, increments logically derived from the form and width of the defined range, all of which are limited values, and all possible combinations of upper and lower limits of the numerical range defined in different forms. Unless otherwise specifically defined in the specification of this disclosure, values ​​outside the numerical range that may occur due to experimental error or rounding of values ​​are also included in the defined numerical range.

[0045] As used in this specification, "comprising" is an open description equivalent to expressions such as "comprising," "containing," "having," and "characteristics," and does not exclude elements, materials, or processes not additionally listed.

[0046] Hereinafter, the temporary support material of the present disclosure and the method for maintaining tunnel concrete lining using the same will be described in detail. However, this is merely illustrative and the present disclosure is not limited to the specific embodiments described illustratively.

[0047] The present disclosure provides a temporary support material inserted into a depression formed by cutting the boundary between a damaged portion of a tunnel concrete lining requiring repair and a sound portion of the tunnel concrete lining.

[0048] As will be explained in more detail below, the above temporary support material may be placed in a concave area that has been pre-cut at the boundary between the damaged portion and the sound portion of the tunnel concrete lining before the damaged portion of the tunnel concrete lining is removed. That is, even if the damaged portion of the concrete is subsequently removed, the above temporary support material can relieve the stress concentrated on the vertical cross-section of the removed damaged portion of the tunnel concrete lining.

[0049] The effect of relieving stress concentrated in the vertical cross-section of the removed tunnel concrete lining damaged section due to the installation of the above temporary support material can be seen from Figure 1 below.

[0050] The image in Figure 1 above shows the stress concentrated in the vertical cross-section of the removed tunnel concrete lining damage (left) and the stress after installing the temporary support described above on the vertical cross-section of the removed tunnel concrete lining damage (right), measured using the general-purpose finite element program ABAQUS.

[0051] As shown in Figure 1 below, it can be seen that the tunnel concrete lining has very high stress concentrated in the vertical section (left) formed by removing the damaged part of the tunnel concrete lining.

[0052] In contrast, if we look at Figure 1, we can see that the vertical cross-section of the damaged portion of the removed tunnel concrete lining has the temporary support material described above installed, and the installed temporary support material significantly relieves the stress concentrated on the vertical cross-section of the damaged portion.

[0053] That is, in one embodiment of the present disclosure, the temporary support material can relieve stress generated at the cross-section of the boundary between the damaged concrete part and the sound concrete part removed during the repair process of the damaged part of the concrete lining by 0.5 times or less, preferably 0.2 times or less, 0.1 times or less, 0.05 times or less, more preferably 0.01 times or less, and even more preferably 100%, but this is just one example and may vary depending on factors such as the area and depth of the damaged part of the removed tunnel concrete lining, the applied ground pressure, and the stiffness / strength of the sound part of the tunnel concrete lining.

[0054] In addition, the above temporary support material can be reused after recovery, and with just a simple installation, it can relieve stress generated in the vertical cross-section of the damaged part of the tunnel concrete lining within the range described above, thereby preventing damage to the sound part of the tunnel concrete lining caused by said stress.

[0055] In one embodiment of the present disclosure, the temporary support material may have a hollow form composed of an exoskeleton and a hollow part, and may have a structure in which a hydraulic inflatable member is disposed on the outer surface of the exoskeleton and a steel pipe member is disposed on the inner surface.

[0056] Since the above temporary support material is a hollow form composed of an exoskeleton and a hollow section, the exoskeleton can be inserted into a depression formed by cutting the boundary of the damaged section of the tunnel concrete lining, and subsequently, the damaged section of the tunnel concrete lining can be removed and repaired from the hollow section.

[0057] In addition, since the above temporary support material has a hydraulic inflatable member positioned on the outer surface of the exoskeleton, the hydraulic inflatable member can be expanded after being inserted into the concave part.

[0058] The temporary support material, having a hydraulic inflatable member positioned on the outer side of the exoskeleton, expands the inflatable member to completely fill the concave area; thus, even if the damaged part of the tunnel concrete lining is subsequently removed, it can completely adhere to the vertical cross-section of the removed damaged part of the tunnel concrete lining to relieve stress.

[0059] In one embodiment of the present disclosure, the exoskeleton may have a hydraulic inflatable member disposed inside a steel support member, or a hydraulic inflatable member may be disposed by bonding a steel pipe member to the exoskeleton, but is not particularly limited if the hydraulic adjustable inflatable member is located on the outer surface.

[0060] In one embodiment of the present disclosure, the steel pipe member may preferably be made of a material having a compressive strength of 20 MPa or more, 40 MPa or more, 50 MPa or more, 60 MPa or more, 70 MPa or more, 100 MPa or more, 200 MPa or more, or 300 MPa or more, and may be made of a material having a compressive strength of 1,000 MPa or less, although the upper limit is not limited.

[0061] Temporary support materials including steel pipe members having a compressive strength within the above range can be relieved of stress concentrated in the vertical cross-section of the damaged portion of the removed tunnel concrete lining without being easily damaged, thereby preventing further damage to the sound portion of the tunnel concrete lining and the embedded reinforcing steel, and ensuring the safety of workers.

[0062] In one embodiment of the present disclosure, the steel support material may be made of a material having an elastic modulus of 10 GPa or more, 15 GPa or more, 20 GPa or more, 25 GPa or more, 30 GPa or more, 40 GPa or more, or 50 GPa or more, and may be made of a material having an elastic modulus of 200 GPa or less, although the upper limit is not limited.

[0063] The above temporary support is equipped with a steel support having high compressive strength and a high elastic modulus, so that even when subjected to stress concentrated on the vertical cross-section of the damaged part of the tunnel concrete lining from which the installed temporary support has been removed, it can maintain its shape with a low strain and relieve the said stress.

[0064] The material of the above-described steel pipe member is not specifically limited as long as it has the compressive strength and elastic modulus described above, but as a non-limiting example, it may be an alloy comprising one or more selected from steel, aluminum, stainless steel, and titanium, or one or more engineering plastics selected from polyphenylene sulfone, polyamide, polyacetal, and polyphenylene oxide.

[0065] The above compressive strength and elastic modulus may be measured in accordance with ASTM D638, but this is not specifically limited as long as it is recognizable by a person skilled in the art.

[0066] In one embodiment of the present disclosure, the temporary support material may have an exoskeleton portion having the same thickness at any height.

[0067] The above temporary support material may be preferred as it includes an exoskeleton having the same thickness at any height, and the temporary support material inserted into the concave part can distribute the stress (axial force) at the boundary surface of the removed tunnel concrete lining applied from the outer side across the entire surface regardless of depth.

[0068] In one embodiment of the present disclosure, the temporary support member has a structure in which the maximum diameter of the cross-section increases linearly in the vertical direction, and the exoskeleton may have an inclination of 5 to 40° in the vertical direction, and in another embodiment, it may be 10 to 40°, 15 to 40°, 20 to 40°, 20 to 35°, or 20 to 30°.

[0069] The above temporary support material can be installed in a concave section formed by cutting perpendicularly into the cross-section of a tunnel concrete lining having a standardized curvature, such that the exoskeleton part has an inclination in the vertical direction within the range described above.

[0070] In addition, although the vertical inclination of the above temporary support may vary depending on the damaged area of ​​the tunnel concrete lining, in terms of excellent workability and stability of the tunnel concrete lining repair work, it may be preferred to carry out the repair work on a cross-sectional area of ​​the damaged tunnel concrete lining where the installation of a temporary support having a vertical inclination within the range described above is possible.

[0071] That is, since the above temporary support material can be installed to fit the concave portion formed by cutting perpendicularly to the cross-section of a tunnel concrete lining having a standardized curvature, the recovered temporary support material can be reused for repair work on another tunnel concrete lining having a standardized curvature.

[0072] In one embodiment of the present disclosure, the temporary support member may be in the shape of a cone, having a circular cross-section in the vertical direction.

[0073] The above temporary support material may be conical in shape, and may be inserted into the formed circular concave portion by cutting the damaged portion of the tunnel concrete lining into a circular shape.

[0074] Even if the above-described conical temporary support forms a concave section perpendicular to the cross-section of a tunnel concrete lining having a standardized curvature, the temporary support can be inserted into the formed concave section because it has the slope described above. Therefore, as previously explained, the above-described conical temporary support may be preferred because, even if it is recovered after repair work on the tunnel concrete lining, the recovered temporary support can be reused if another tunnel concrete lining has a standardized curvature.

[0075] In addition, the above-mentioned conical temporary support can relieve stress concentrated on the vertical cross-section of the tunnel concrete riding damage section through an excellent arching effect, so the installed temporary support does not break and can relieve strong stress concentrated on the vertical cross-section even at a low strain rate, making it a preferred choice.

[0076] In one embodiment of the present disclosure, the hydraulic adjustable expandable member may have a hydraulic injection hole and a hydraulic hose arranged in the opposite direction to be inserted into the concave portion.

[0077] The above temporary support material allows a hydraulically adjustable inflatable member to expand by filling the hydraulic injection port with gas from a hydraulic hose, and the expanded hydraulically adjustable inflatable member can be fixed by completely filling the concave portion, and the inlet injection port and hydraulic hose are arranged in the direction described above so that air injection of the hydraulically adjustable inflatable member can be facilitated.

[0078] Therefore, even if the damaged portion of the tunnel concrete lining is subsequently removed, the above temporary support material remains in close contact with and fixed to the vertical cross-section of the removed tunnel concrete lining, thereby supporting and alleviating the stress applied to the vertical cross-section of the damaged portion of the removed concrete lining, and thus excellent stability can be ensured during the repair work of the concrete lining.

[0079] In one embodiment of the present disclosure, the temporary support material may be provided with an exoskeleton having a thickness ratio of 1:1 to 1:5 between the hydraulic inflatable member and the steel pipe member before expansion, in order to achieve excellent support performance.

[0080] Temporary support members equipped with steel support members of the above-mentioned thickness range may be preferred because they possess high strength and stiffness, allowing stresses occurring in the vertical cross-section of the removed damaged concrete section to be relieved to failure and low deformation, but this is not necessarily a limitation.

[0081] As one embodiment of the present disclosure, the temporary support material (1000) may be an embodiment shown in FIG. 2 below.

[0082] In FIG. 2 below, the temporary support material (1000) may be in a hollow form and may include an exoskeleton part (100) having a steel pipe member (110) on the inner side and a hydraulically adjustable expandable member (120) on the outer side, and may have a hollow part (200) formed inside the exoskeleton part (100).

[0083] In FIG. 2 below, the temporary support material (1000) includes an exoskeleton part (100) having a uniform thickness in the height direction, and may also be a conical shape with a circular cross-section in the vertical direction and a structure in which the maximum diameter of the cross-section increases linearly in the vertical direction.

[0084] The above-described conical temporary support material can provide excellent support performance by maximally dispersing the stress applied to the cross-section of the removed concrete lining through the hollow section, even when the damaged portion of the concrete lining is removed.

[0085] In addition, the above temporary support material has a structure in which the maximum diameter of the cross-section increases linearly in the vertical direction, and the exoskeleton part has an inclination of 5 to 40° in the vertical direction, so it can be used in tunnel concrete lining having a standardized curvature. That is, the above temporary support material can be reused in other tunnel concrete lining repair work after the tunnel concrete lining repair work is completed.

[0086] According to the embodiment of FIG. 2 below, the temporary support material (1000) may be provided with a hydraulically adjustable inflatable member (120) that includes an inflatable tube (121), and may have a hydraulic injection port (122) and a hydraulic hose (123) in the opposite direction to where the temporary support material (1000) is inserted into the concave part. In the embodiment of FIG. 2 below, the temporary support material (1000) provided with the hydraulic injection port (122) and the inflow hose (123) may be preferred because gas can be injected into the inflatable tube (121) through the hydraulic injection port (122) and the hydraulic hose (123) even after being inserted into the concave part, thereby allowing the temporary support material (1000) to be easily fixed in the concave part.

[0087] For the reasons mentioned above, the above-mentioned temporary support material offers superior economic efficiency compared to the temporary support materials used in conventional tunnel concrete lining repair work, and can resolve the environmental pollution problem caused by civil engineering waste resulting from the single-use conventional temporary support materials.

[0088] Therefore, the above temporary support material can be usefully utilized as a temporary support material for concrete lining repair work, and in particular, it can be usefully utilized as a temporary support material for tunnel concrete lining repair work in terms of worker safety and preventing additional damage to sound concrete parts.

[0089] The following describes a method for maintaining tunnel concrete lining using the above-mentioned temporary support material.

[0090] The present disclosure may provide a method for maintaining a tunnel concrete lining, comprising the steps of: cutting the boundary of a damaged portion of the tunnel concrete lining with a water jet to form a depression; inserting the temporary support material described above into the depression; cutting the damaged portion of the tunnel concrete lining with a water jet; repairing the cut damaged portion; shrinking and recovering the conical steel support material inserted into the depression; and repairing the depression.

[0091] The above tunnel concrete lining maintenance method uses the temporary support material described above to relieve stress concentrated in the vertical cross-section of the cut tunnel concrete lining damage section even when the damaged section of the tunnel concrete lining is cut with a water jet, thereby preventing additional cracks caused by said stress and preventing accidents caused by tunnel collapse, thus ensuring the safety of workers.

[0092] In addition, since the above tunnel concrete lining maintenance method adopts a process of cutting damaged or concave parts of the tunnel concrete lining with a water jet, it can prevent additional damage to reinforcing bars and sound parts of the concrete lining compared to the conventional method of removing damaged parts of the concrete lining with a hand breaker, and since it does not require a high level of skill from the operator, a consistent work speed can be maintained even when performed by operators of different skill levels.

[0093] In one embodiment of the present disclosure, the temporary support material may be installed as shown in Fig. 3 below when viewed in the direction of the back of the concrete lining.

[0094] In FIG. 3 below, a temporary support material (1000) is inserted into a depression formed at the interface between the damaged portion of the tunnel concrete lining and the sound portion of the tunnel concrete lining, and the inserted temporary support material (1000) can be completely filled into the depression by expanding a hydraulically adjustable expandable member (120).

[0095] As shown in FIG. 3 above, the temporary support material (1000) expands the hydraulically adjustable expandable member (120) to fill the concave portion, and subsequently, even if the damaged portion of the tunnel concrete lining is removed, it adheres to the vertical cross-section of the removed damaged portion of the tunnel concrete lining, thereby relieving the stress concentrated on the vertical cross-section of the removed damaged portion of the tunnel concrete.

[0096] As shown in Figure 3 below, the above temporary support material may be preferred in the form of a cone with a circular cross-section in the vertical direction, as this can further alleviate the stress concentrated in the vertical cross-section of the removed tunnel concrete damaged part through an arching effect, but this is not necessarily limited.

[0097] In one aspect of the present disclosure, a tunnel concrete lining maintenance method may further include the step of detecting damage to the concrete lining using a non-destructive inspection device.

[0098] The above non-destructive testing may be performed using commonly known methods such as radiographic testing, ultrasonic testing, vibration testing, extraction testing, or rebar detection; however, radiographic testing or ultrasonic testing may be preferred to ensure rapid construction speed and to detect damage to the tunnel concrete lining at specific depths.

[0099] The step of detecting the damage to the concrete lining described above can be performed by detecting the damage to the tunnel concrete lining through non-destructive testing to form the concave area described above, and can install temporary support materials to fit the detected damage to the tunnel concrete lining.

[0100] In one aspect of the present disclosure, the tunnel concrete lining maintenance method may further include the step of inspecting the repaired damaged portion and the repaired concave portion with a non-destructive inspection device.

[0101] Since the above tunnel concrete lining maintenance method uses temporary support materials, the stress generated in the cross-section of the removed tunnel concrete lining can be minimized until concrete is poured and cured in the cut tunnel concrete damaged area.

[0102] That is, the above-described tunnel concrete lining maintenance method can solve problems such as damage to the sound part of the tunnel concrete and deformation of the repaired damaged part caused by stress in the vertical cross-section of the cut tunnel concrete lining damage part, and can be preferred because it can perfectly repair the tunnel concrete damage part without damaging the reinforcing steel and the sound part of the concrete compared to the conventional shotcrete method.

[0103] According to one embodiment of the present disclosure, a method for maintaining a tunnel concrete lining may be performed sequentially as shown in the schematic diagram in Fig. 4 below, and in particular, the boundary surface of the damaged part of the tunnel concrete lining may be cut with a water jet to form a depression, the damaged part of the tunnel concrete lining may be cut, and the temporary support material described above may be installed.

[0104] Therefore, the tunnel concrete lining maintenance method can repair damaged sections of the tunnel concrete lining with excellent stability, excellent cost-effectiveness, and high mechanical strength (perfect restoration).

[0105] Below, each step of the above tunnel concrete lining maintenance method will be explained in detail.

[0106] (Step for detecting damage to the tunnel concrete lining)

[0107] In one embodiment of the present disclosure, the step of detecting damage to the tunnel concrete lining may be to detect it using a non-destructive inspection device that uses energy lines such as ultrasound or elastic waves on the tunnel concrete lining.

[0108] That is, the step of detecting damage to the tunnel concrete lining can be performed by inspecting with a non-destructive testing device to calculate the area and depth of the damage to the tunnel concrete lining, determine the height and cross-sectional diameter of the temporary support material to be inserted into the depression, and form a depression by cutting the boundary surface of the damage to be described later according to the area and depth.

[0109] According to one embodiment of the present disclosure, the step of detecting damage to the tunnel concrete lining can determine the depth and area of ​​the damage (the area requiring repair and reinforcement) using a non-destructive testing device.

[0110] At this time, the tunnel concrete damage detected by the above non-destructive testing device may be 80% or less, 70% or less, 60% or less, 50% or less, 40% or less, or 30% or less with respect to the total thickness of the tunnel concrete lining, although it may not be limited to a lower limit, and may be 5% or more or 10% or more.

[0111] In other words, since the damaged portion of the tunnel concrete lining corresponds to only a part of the total thickness of the tunnel concrete lining, if the detected damaged portion is cut, strong stress is applied to the cut vertical section, which may cause additional damage to the sound portion of the tunnel concrete lining and the reinforcing bars.

[0112] (Step of forming a depression by cutting the boundary of the damaged section of the tunnel concrete lining with a water jet)

[0113] In one embodiment of the present disclosure, the tunnel concrete lining maintenance method includes the step of forming a depression by cutting the boundary surface of the detected damaged portion of the tunnel concrete lining with a water jet, as shown in FIG. 5.

[0114] The above-mentioned concave portion may be formed in a square, triangular, circular, or elliptical shape depending on the detected damage to the tunnel concrete lining; however, cutting it into a circular shape may be preferred in terms of the continuous reuse of the installed temporary support material and the efficient distribution of strong stress applied to the vertical cross-section of the cut tunnel concrete damage material, thereby providing excellent support performance.

[0115] The above-mentioned depression may be preferably formed by cutting the boundary of the tunnel concrete damage section according to the depth of the detected tunnel concrete lining damage section, and a temporary support material can be easily selected according to the depth of the depression being cut, and in some cases, it may be acceptable for the installed temporary support material to be higher than the depth of the formed depression.

[0116] In addition, the step of forming the above-mentioned concave section is preferred because, since the boundary of the damaged section of the tunnel concrete lining is cut using a water jet, there is not a significant difference in work time depending on the operator's skill level, and compared to conventional hand breakers, it can prevent damage to the sound section of the undamaged tunnel concrete lining and internal reinforcing bars.

[0117] In one embodiment of the present disclosure, the step of forming the concave portion may be formed by cutting the boundary surface of the damaged portion of the tunnel concrete in a direction perpendicular to the cutting surface of the tunnel concrete lining.

[0118] The concave portion formed in the vertical direction of the above-mentioned cutting surface is designed according to the standardized tunnel curvature described above, making it easy to insert a temporary support material with a vertical inclination within a certain range.

[0119] (Step of inserting the temporary support material described above into the above-mentioned concave portion)

[0120] In one embodiment of the present disclosure, the tunnel concrete lining maintenance method can efficiently distribute strong stress applied to the vertical cross-section of the cut tunnel concrete damaged part by inserting the temporary support material described above into the formed depression as shown in Fig. 6 below.

[0121] As shown in Fig. 6 below, the step of inserting the temporary support material is inserted into a depression formed in the vertical direction of the cutting boundary surface, so it may be preferred that the temporary support material have a vertical inclination of 5 to 40° depending on the damaged area of ​​the tunnel concrete lining having a standardized curvature.

[0122] In addition, since the above-mentioned temporary support material has a constant slope as described above, if the tunnel concrete lining has a standardized curvature, the recovered temporary support material can be reused, thereby providing excellent economic efficiency and excellent eco-friendliness.

[0123] In one embodiment of the present disclosure, the temporary support material inserted into the concave portion may be completely fixed to the concave portion by expanding a hydraulically adjustable inflatable member provided in the temporary support material, as shown in FIG. 7 below.

[0124] The above temporary support member expands an expandable member from hydraulic pressure, allowing the temporary support member inserted into the concave part to cut the damaged part of the tunnel concrete lining described later without shaking, and may be preferred because the temporary support member does not come loose or shake even when the damaged part of the tunnel concrete lining is cut.

[0125] (Step of cutting the damaged portion of the tunnel concrete lining with a water jet)

[0126] In one embodiment of the present disclosure, the step of cutting the damaged portion of the tunnel concrete lining may be performed in the hollow portion of the temporary support material inserted into the concave portion, as shown in FIG. 8 below.

[0127] In addition, since the step of cutting the damaged portion of the tunnel concrete lining uses a water jet in the same way as the step of forming the concave portion described above, additional damage to the sound portion of the tunnel concrete lining and the reinforcing steel embedded in the concrete can be prevented, and compared to the conventional handbrake method, the difference in construction period may not increase significantly depending on the skill level of the worker.

[0128] The above tunnel concrete lining maintenance method can relieve stress concentrated in the vertical cross-section (direction of the hydraulically adjustable expandable member) of the damaged part of the tunnel concrete lining even if the damaged part of the tunnel concrete lining is removed, due to the temporary support material inserted into the concave part.

[0129] In the above tunnel concrete lining maintenance method, the stress relief effect on the vertical cross-section of the removed tunnel concrete lining damaged part due to the temporary support material can be confirmed in Figure 1 below, as described above.

[0130] As shown in Figure 1 below, it can be seen that the tunnel concrete lining maintenance method with the installation of temporary support significantly alleviates stress concentration occurring in the vertical cross-section of the removed damaged tunnel concrete. In addition, since the tunnel concrete lining maintenance method installs temporary support, it can prevent damage to the reinforcing bars and the sound parts of the tunnel concrete caused by the stress concentration, and since this has been described in detail above, a detailed explanation will be omitted.

[0131] (Step to repair the above-mentioned cut damage)

[0132] In one aspect of the present disclosure, the tunnel concrete lining maintenance method may include the step of cutting the damaged portion of the tunnel concrete lining described above and repairing the cut damaged portion of the tunnel concrete lining through the hollow portion of the installed temporary support material.

[0133] The step of repairing the cut damaged portion may be carried out as shown in Fig. 9 below, in terms of facilitating the easy recovery of the temporary support and reusing the recovered temporary support, by separately installing a formwork on the inner side of the temporary support.

[0134] In addition, the step of repairing the cut damaged portion is performed while the temporary support material described above is installed, so compared to the conventional shotcrete method, a worker can pour and cure concrete on the damaged tunnel concrete in a stable state for a long period of time.

[0135] Therefore, compared to the conventional shotcrete method, the above tunnel concrete lining maintenance method allows the restored concrete to have excellent strength and adhesion, so it may not easily spall.

[0136] In addition, the above tunnel concrete lining maintenance method involves installing temporary support materials to provide stable support, thereby allowing concrete to be poured and cured in the damaged areas of the removed tunnel concrete lining for a sufficient period. Consequently, the tunnel concrete lining can be maintained and repaired to a strength similar to, identical to, or even better than, that of the initially constructed tunnel concrete lining, thus maintaining the tunnel concrete lining with excellent stability for a long period.

[0137] In one aspect of the present disclosure, the tunnel concrete lining maintenance method may further include, after the step of repairing the cut damage described above, a step of verifying the soundness and adhesion status of the concrete repaired in the cut damage by non-destructive testing.

[0138] Since the above tunnel concrete lining maintenance method uses temporary support materials, as described above, sufficient time can be provided for pouring and curing concrete in the damaged parts of the tunnel concrete lining, and spalling of the repaired concrete lining can be prevented. Furthermore, through additional inspection, the adhesion and soundness of the repaired concrete lining can be measured, thereby enabling more complete maintenance of the concrete lining.

[0139] (Step of shrinking and recovering the temporary support material inserted into the above-mentioned depression)

[0140] In one aspect of the present disclosure, the tunnel concrete lining maintenance method described above can repair damaged parts of the tunnel concrete lining and recover installed temporary support materials.

[0141] As described above, the temporary support material is equipped with a hydraulically adjustable inflatable member, so it can not only be expanded by hydraulic pressure but also recover the gas injected into the hydraulically adjustable inflatable member, thereby enabling easy recovery of the temporary support material fixed to the vertical cross-section of the damaged part of the tunnel concrete lining.

[0142] Therefore, the above-mentioned temporary support material can be easily installed and retrieved in the tunnel concrete lining maintenance method described above, and the retrieved temporary support material can be reused as a temporary support material in the concrete lining maintenance construction of another tunnel having a standardized curvature, thus possessing excellent economic efficiency and excellent eco-friendliness.

[0143] (Step of repairing the above-mentioned depression)

[0144] In one embodiment of the present disclosure, the tunnel concrete lining maintenance method may include the step of recovering temporary support material in the depression, as shown in FIG. 10 below, and then pouring and curing mortar in the depression to restore the depression.

[0145] In the step of repairing the above-mentioned depression, unlike concrete that is poured and cured in the damaged part of the cut tunnel concrete lining, it is preferred to use mortar with a lower proportion of aggregate than concrete, as the depression is filled between the damaged part of the already repaired tunnel concrete lining and the sound part of the tunnel concrete lining.

[0146] In one aspect of the present disclosure, the tunnel concrete lining maintenance method can verify the soundness and adhesion of the repaired concave portion using a non-destructive testing device, in the same manner as described above, as with the damaged portion of the repaired tunnel concrete lining.

[0147] Therefore, the above temporary support material is simple to install, easy to retrieve, and can be reused in other tunnel concrete maintenance, so a tunnel concrete lining maintenance method using it can have excellent economic efficiency.

[0148] In addition, the above temporary support material alleviates stress concentration in the vertical cross-section of the damaged section of the cut tunnel concrete lining, thereby ensuring worker safety during tunnel concrete lining maintenance and preventing additional damage to the sound section and reinforcing bars caused by stress concentration on the cut surface of the damaged section.

[0149] That is, according to one embodiment of the present disclosure, a tunnel concrete maintenance method, in addition to the effects of using the temporary support material described above, uses a water jet, so that changes in construction speed are minimal depending on the skill level of the worker, and additional damage to sound parts and reinforcing bars can be prevented when removing damaged parts of the tunnel concrete lining.

[0150] Although embodiments of the present invention have been described, the spirit of the present invention is not limited by the embodiments presented in this specification. Those skilled in the art who understand the spirit of the present invention may easily propose other embodiments within the scope of the same spirit by adding, changing, deleting, or adding components, and such are also to be considered to fall within the scope of the spirit of the present invention. Explanation of the symbols

[0151] 100: Exoskeletal joint 110: Steel pipe member 120: Hydraulic adjustable inflatable member 121: Inflatable tube 122 Hydraulic injection port 123 Hydraulic Hose 200: Chinese government 1000: Temporary support materials

Claims

Claim 1 A temporary support material inserted into a hollow section formed by cutting the boundary between a damaged section of a tunnel concrete lining requiring repair and a sound section of a tunnel concrete lining, wherein the temporary support material is a hollow type composed of an exoskeleton and a hollow section, wherein a hydraulically adjustable inflatable member is disposed on the outer surface of the exoskeleton and a steel pipe member is disposed on the inner surface, and wherein the temporary support material has a structure in which the maximum diameter of the cross-section increases linearly in the vertical direction, and wherein the exoskeleton has an inclination of 5 to 40° in the vertical direction. Claim 2 In claim 1, the temporary support material is a temporary support material in which the exoskeleton part has the same thickness at any height. Claim 3 delete Claim 4 In claim 1, the temporary support is a conical temporary support having a circular cross-section in the vertical direction. Claim 5 In claim 1, the hydraulic adjustable expandable member is a temporary support material having a hydraulic injection hole and a hydraulic hose arranged in the opposite direction to be inserted into a concave part. Claim 6 In claim 1, the steel pipe member is a temporary support member formed of a material having a compressive strength of 20 MPa or more and an elastic modulus of 10 GPa or more as measured by ASTM D638. Claim 7 In claim 1, the exoskeleton is a temporary support material in which the thickness ratio of the hydraulic inflatable member and the steel pipe member before expansion is 1:1 to 1:

5. Claim 8 In claim 1, the temporary support material is a temporary support material that alleviates stress occurring in the vertical cross-section of the concrete damage removed during the repair process of the tunnel concrete lining damage to 0.5 times or less. Claim 9 A method for maintaining a tunnel concrete lining, comprising: a step of forming a depression by cutting the boundary of a damaged portion of the tunnel concrete lining with a water jet; a step of inserting a temporary support material selected from any one of claims 1, 2 and 4 to 8 into the depression; a step of cutting the damaged portion of the tunnel concrete lining with a water jet; a step of repairing the cut damaged portion; a step of recovering the temporary support material inserted into the depression; and a step of repairing the depression. Claim 10 In claim 9, the tunnel concrete lining maintenance method is a tunnel concrete lining maintenance method in which the expandable member of a conical steel support inserted into a concave portion is expanded to completely fix the inserted temporary support in the concave portion. Claim 11 In claim 9, the tunnel concrete lining maintenance method further comprises the step of detecting damage to the concrete lining using a non-destructive inspection device. Claim 12 In claim 9, the tunnel concrete lining maintenance method further comprises the step of inspecting the repaired damaged portion and the repaired concave portion with a non-destructive inspection device.

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