Combined reinforcing method for repairing chipping and cracking of second lining of tunnel

Abstract

The invention relates to a combined reinforcing method for repairing chipping and cracking of a second lining of a tunnel. The combined reinforcing method comprises the steps that S1, surrounding rock is stabilized in chipping and cracking areas of the second lining of the tunnel through an anchor cable scheme; s2, the loose surrounding rock behind the lining is subjected to backfill grouting reinforcement; and S3, carbon fiber cloth is embedded into the inner surface of the tunnel lining for reinforcement. The construction does not need large machines and tools, construction is easy and convenient, the construction period is short, and normal operation of the tunnel is not affected; the problems of chipping and cracking of the second lining of the tunnel are solved at the same time through the combined measures of anchor cables, backfill grouting and carbon fiber cloth, and the structural performance of the lining is comprehensively recovered; meanwhile, the bearing capacity and durability of the lining are improved through the carbon fiber cloth, and the normal use function of the tunnel is ensured.

Description

Technical Field

[0001] The invention relates to the technical field of tunnel engineering repair, and in particular to a combined reinforcement method for repairing block loss and cracking of a tunnel secondary lining. Background Art

[0002] In tunnel engineering, the falling and cracking of the secondary lining concrete are common defects, which seriously affect the safety and durability of the tunnel. Traditional repair methods can usually only solve a single problem. For example, grouting, surface sealing and caulking are commonly used to repair cracks, and local reinforcement methods are often used to repair falling blocks. These methods are difficult to fully restore the structural performance of the tunnel lining. In addition, traditional methods may also be limited by complex construction, long construction period or large impact on tunnel clearance.

[0003] Chinese invention patent CN110778332A (publication date: February 11, 2020) discloses a different-diameter adaptive expansion grouting device and reinforcement method for cracked and damaged parts of the tunnel secondary lining. The grouting device can simultaneously realize compaction grouting and splitting grouting. Through compaction and splitting filling, the overall strength and stability of the reinforced surrounding rock are improved.

[0004] Although the above-mentioned prior art effectively solves the cracking problem of the tunnel secondary lining, it cannot solve the problems of block falling and cracking at the same time, nor can it achieve the effect of significantly improving the overall bearing capacity and durability of the lining and fully restoring the structural performance of the tunnel lining. Based on the shortcomings of the prior art, the present invention provides a combined reinforcement method for repairing the block falling and cracking of the tunnel secondary lining. The method is a comprehensive reinforcement method that can solve the problems of block falling and cracking at the same time and improve the overall bearing capacity and durability of the lining. Summary of the invention

[0005] The present invention provides a combined reinforcement method for repairing cracks in the secondary lining of a tunnel, comprising the following steps:

[0006] Step S1: Using anchor cable scheme to stabilize surrounding rock in the area of ​​block loss and cracks in the tunnel secondary lining;

[0007] Step S2: backfill and grout the loose surrounding rock behind the lining for reinforcement;

[0008] Step S3: embedding carbon fiber cloth into the inner surface of the tunnel lining for reinforcement.

[0009] Furthermore, in step S1, the prestress of the anchor cable is 450-550 kN, the length is 15-20 m, the anchor end is 6-10 m long, and the spacing and row spacing of the anchor cables are equal.

[0010] Furthermore, there are several anchor cables, each of which is a high-strength steel strand with a nominal diameter of 15-17 mm and a tensile strength of 1800-1900 MPa; the tensioning force of each anchor cable is 120-130 kN, and the hole diameter is 105-115 mm.

[0011] Furthermore, in step S2, the loose surrounding rock behind the lining is backfilled and grouting reinforced using steel pipes. By pressing cement slurry into the broken and loose rock mass and backfilling the voids behind the lining, the lining can be closely attached to the surrounding rock and the reaction force of the surrounding rock can be fully utilized.

[0012] Furthermore, the steel flower pipes are 1.5-2.5 m long and 40-45 mm in diameter, and the spacing and row spacing of the steel flower pipes are equal.

[0013] Furthermore, the spacing and row spacing of the anchor cables are greater than the spacing and row spacing of the steel flower pipes.

[0014] Furthermore, the step S3 specifically includes the following steps:

[0015] Step S31: concrete surface treatment;

[0016] Step S32: pre-coating primer;

[0017] Step S33: scraping putty;

[0018] Step S34: laying carbon fiber cloth;

[0019] Step S35: maintenance;

[0020] Step S36: Apply special paint.

[0021] Further, the step S34 includes the following steps:

[0022] Step S341: double-layer steel mesh lining or sprayed steel fiber lining is set at the location where the block falls, and 1-2% steel fiber sprayed concrete is used to repair the crack location;

[0023] Step S342: embedding carbon fiber cloth into the inner surface of the tunnel lining for reinforcement;

[0024] Step S343: The carbon fiber cloth is fully laid along the circumference of the tunnel.

[0025] The use of carbon fiber cloth for construction does not require large machinery and equipment, and is simple to operate and has a short construction period. Its thickness is no more than 2mm and does not affect the normal operation of the tunnel. Its tensile strength is 10-15 times higher than that of ordinary steel, and its weight is 23% of that of steel. It can be bent and wound into shape, and is acid and alkali resistant and corrosion resistant. It can effectively improve the bending and tensile properties of the lining, prevent cracks from occurring, and extend the service life of the tunnel.

[0026] Furthermore, in step S343, when the carbon fiber cloth is fully laid along the circumferential direction of the tunnel, the width of the circumferential belt is 1-2m, and one belt is laid every 1.5-3.0m in the longitudinal direction.

[0027] Compared with the prior art, the advantages and effects of this application are as follows:

[0028] 1. The present invention provides a combined reinforcement method for repairing the falling and cracking of the secondary lining of a tunnel. Through the combined measures of anchor cables, backfill grouting and carbon fiber cloth, the problem of falling and cracking of the secondary lining of the tunnel is solved at the same time, and the structural performance of the lining is fully restored.

[0029] 2. The combined reinforcement method for repairing cracks in the second lining of a tunnel provided by the present invention achieves the following effects by using carbon fiber cloth: ① Improving the bearing capacity and durability of the lining; utilizing the advantages of high strength, corrosion resistance, light weight, and convenient construction of carbon fiber cloth, the bending and tensile properties of the lining are effectively improved, cracks are prevented, and the service life of the tunnel is extended; ② Simple construction and short construction period; carbon fiber cloth construction does not require large machinery and tools, is simple to operate, has a short construction period, and does not affect the normal operation of the tunnel; ③ Does not affect the clearance of the tunnel; the thickness of the carbon fiber cloth is not more than 2.0 mm, which will not change the clearance size of the tunnel, ensuring the normal use function of the tunnel; ④ Strong applicability; carbon fiber cloth can be bent and wound into shape, and is suitable for various curved surfaces and special-shaped components.

[0030] The above description is only an overview of the technical solution of the present application. In order to more clearly understand the technical means of the present application so that it can be implemented in accordance with the contents of the specification, and to make the above and other purposes, features and advantages of the present application more obvious and easy to understand, the following is a detailed description of the preferred embodiments of the present application in conjunction with the accompanying drawings as follows.

[0031] Based on the detailed description of the specific embodiments of the present application in combination with the accompanying drawings below, those skilled in the art will become more aware of the above and other objects, advantages and features of the present application. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the drawings required for use in the embodiments or the prior art descriptions are briefly introduced below. Obviously, the drawings described below are some embodiments of the present application. For ordinary technicians in this field, other drawings can also be obtained based on these drawings without creative work. In all drawings, similar elements or parts are generally identified by similar reference numerals. In the drawings, each element or part is not necessarily drawn according to the actual scale.

[0033] in:

[0034] Figure 1 It is a schematic diagram of anchor cable construction in a combined reinforcement method for repairing cracks in the secondary lining of a tunnel;

[0035] Figure 2 It is a schematic diagram of grouting behind the lining in a combined reinforcement method for repairing the cracking of the tunnel secondary lining;

[0036] Among them: 1-anchor cable; 2-steel flower pipe. DETAILED DESCRIPTION

[0037] To make the purpose, technical scheme and advantages of the embodiment of the present application clearer, the technical scheme in the embodiment of the present application will be clearly and completely described below in conjunction with the accompanying drawings in the embodiment of the present application. Obviously, the described embodiment is a part of the embodiment of the present application, rather than all of the embodiments. In the following description, specific details such as specific configuration and components are provided only to help fully understand the embodiments of the present application. Therefore, it should be clear to those skilled in the art that various changes and modifications can be made to the embodiments described herein without departing from the scope and spirit of the present application. In addition, for clarity and brevity, the description of known functions and structures is omitted in the embodiment.

[0038] It should be understood that the references to "one embodiment" or "this embodiment" throughout the specification mean that the specific features, structures, or characteristics associated with the embodiment are included in at least one embodiment of the present application. Therefore, the references to "one embodiment" or "this embodiment" appearing throughout the specification do not necessarily refer to the same embodiment. In addition, these specific features, structures, or characteristics may be combined in any suitable manner in one or more embodiments.

[0039] In addition, the present application may repeat reference numerals and / or letters in different examples. This repetition is for the purpose of simplicity and clarity, and does not in itself indicate the relationship between the various embodiments and / or settings discussed.

[0040] The term "and / or" in this article is only a description of the association relationship of associated objects, indicating that there can be three relationships. For example, A and / or B can mean: A exists alone, B exists alone, and A and B exist at the same time. The term " / and" in this article describes another type of association object relationship, indicating that there can be two relationships. For example, A / and B can mean: A exists alone, and A and B exist alone. In addition, the character " / " in this article generally indicates that the associated objects before and after are in an "or" relationship.

[0041] The term "at least one" in this article is merely a description of the association relationship of associated objects, indicating that there may be three relationships. For example, at least one of A and B can mean: A exists alone, A and B exist at the same time, and B exists alone.

[0042] It should also be noted that, in this article, relational terms such as first and second, etc. are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Moreover, the terms "include", "comprises" or any other variations thereof are intended to cover non-exclusive inclusions.

[0043] Example 1

[0044] This embodiment introduces a combined reinforcement method for repairing cracks in the secondary lining of a tunnel provided by the present invention, comprising the following steps:

[0045] Step S1: Using anchor cable scheme to stabilize surrounding rock in the area of ​​block loss and cracks in the tunnel secondary lining;

[0046] Step S2: backfill and grout the loose surrounding rock behind the lining for reinforcement;

[0047] Step S3: embedding carbon fiber cloth into the inner surface of the tunnel lining for reinforcement.

[0048] Preferably, in step S1, the prestress of the anchor cable 1 is 450-550 kN, the length is 15-20 m, the anchor end is 6-10 m long, and the spacing and row spacing of the anchor cables 1 are equal.

[0049] Preferably, there are several anchor cables 1, each of which is a high-strength steel strand with a nominal diameter of 15-17 mm and a tensile strength of 1800-1900 MPa; the tensioning force of each anchor cable 1 is 120-130 kN, and the hole diameter is 105-115 mm.

[0050] Preferably, in step S2, the loose surrounding rock behind the lining is backfilled and grouting reinforced using the steel flower pipe 2. By pressing cement slurry into the broken and loose rock mass and backfilling the voids behind the lining, the lining can be closely attached to the surrounding rock and the reaction force of the surrounding rock can be fully utilized.

[0051] Preferably, the steel flower tubes 2 are 1.5-2.5 m long and 40-45 mm in diameter, and the spacing and row spacing of the steel flower tubes 2 are equal.

[0052] Preferably, the spacing and row spacing of the anchor cables 1 are greater than the spacing and row spacing of the steel flower tubes 2 .

[0053] Preferably, the step S3 specifically includes the following steps:

[0054] Step S31: concrete surface treatment;

[0055] Step S32: pre-coating primer;

[0056] Step S33: scraping putty;

[0057] Step S34: laying carbon fiber cloth;

[0058] Step S35: maintenance;

[0059] Step S36: Apply special paint.

[0060] Preferably, the step S34 comprises the following steps:

[0061] Step S341: double-layer steel mesh lining or sprayed steel fiber lining is set at the location where the block falls, and 1-2% steel fiber sprayed concrete is used to repair the crack location;

[0062] Step S342: embedding carbon fiber cloth into the inner surface of the tunnel lining for reinforcement;

[0063] Step S343: The carbon fiber cloth is fully laid along the circumference of the tunnel.

[0064] The use of carbon fiber cloth for construction does not require large machinery and equipment, and is simple to operate and has a short construction period. Its thickness is no more than 2mm and does not affect the normal operation of the tunnel. Its tensile strength is 10-15 times higher than that of ordinary steel, and its weight is 23% of that of steel. It can be bent and wound into shape, and is acid and alkali resistant and corrosion resistant. It can effectively improve the bending and tensile properties of the lining, prevent cracks from occurring, and extend the service life of the tunnel.

[0065] Preferably, in step S343, when the carbon fiber cloth is fully laid along the circumferential direction of the tunnel, the width of the circumferential belt is 1-2m, and one belt is laid every 1.5-3.0m in the longitudinal direction.

[0066] The technical effect achieved by this embodiment is as follows: this embodiment provides a combined reinforcement method for repairing the falling blocks and cracks of the tunnel secondary lining. Through the combined measures of anchor cables, backfill grouting and carbon fiber cloth, the problems of falling blocks and cracks in the tunnel secondary lining are solved at the same time, and the structural performance of the lining is fully restored; at the same time, the many advantages of carbon fiber cloth are utilized to achieve the effect of improving the bearing capacity and durability of the lining, simple construction, short construction period and no impact on the tunnel clearance.

[0067] Example 2

[0068] Based on Example 1, this example introduces an application case of the present application in a tunnel.

[0069] A block of secondary lining concrete fell off on the left side of a tunnel vault, with a vertical length of 2m, a horizontal width of 1.1m, and a falling area of ​​2.2m 2 , in the shape of an inverted pot bottom, with a visible waterproof layer; there is a longitudinal crack extending along the longitudinal direction, with a width of 2 to 3 cm and a length of about 4 m, and the fire retardant coating has peeling and delamination. Use this application for repair:

[0070] Step S1: Use anchor cable solution to stabilize surrounding rock in the area of ​​block loss and cracks in the tunnel secondary lining

[0071] Anchor cable 1 is arranged in the area of ​​falling blocks and cracks. The prestress of anchor cable 1 is 500kN, the length is 18m, the anchor end is 8m long, and the spacing is 3.0m×3.0m. Four high-strength steel strands with a nominal diameter of 15.24mm and a tensile strength of 1860MPa are used as anchor cable 1. The diameter of the hole of anchor cable 1 is 110mm, and the tension of each anchor cable 1 is 125kN. For the schematic diagram of anchor cable construction, please refer to Figure 1 .

[0072] Step S2: Backfill and grout the loose surrounding rock behind the lining

[0073] Use 2m long and 42mm diameter steel pipes 2 with a spacing of 2.0m×2.0m to backfill and grout the surrounding rock behind the lining to ensure that the lining is tightly combined with the surrounding rock. Figure 2 .

[0074] Step S3: Embed carbon fiber cloth on the inner surface of the tunnel lining for reinforcement

[0075] Double-layer steel mesh lining or sprayed steel fiber lining is set at the location of the fallen block. After the crack position is repaired with 1.5% sprayed steel fiber concrete, carbon fiber cloth is laid on the entire section for lining reinforcement. The carbon fiber cloth is fully laid along the tunnel ring (side wall and arch), the ring width is 1.5m, and one is laid every 1.5 to 3.0m in the longitudinal direction. The construction process includes: concrete surface treatment, pre-coating primer, scraping putty, pasting carbon fiber cloth, maintenance, and painting special paint.

[0076] The above description is only the preferred embodiment of the present invention, which does not limit the protection scope of the present invention. For those skilled in the art, the present invention can be modified and varied in various ways. Within the spirit and principle of the present invention, any change, modification, replacement, integration and parameter change of these embodiments by conventional substitution or capable of achieving the same function without departing from the principle and spirit of the present invention shall fall within the protection scope of the present invention.

Claims

1. A combined reinforcement method for repairing cracks in the secondary lining of a tunnel, characterized in that: The following steps are involved: Step S1: Using anchor cable scheme to stabilize surrounding rock in the area of ​​block loss and cracks in the tunnel secondary lining; Step S2: backfill and grout the loose surrounding rock behind the lining; Step S3: embedding carbon fiber cloth on the inner surface of the tunnel lining for reinforcement.

2. A combined reinforcement method for repairing cracks in the secondary lining of a tunnel according to claim 1, characterized in that: In step S1, the prestress of the anchor cable (1) is 450-550 kN, the length is 15-20 m, the anchor end is 6-10 m long, and the spacing and row spacing of the anchor cables (1) are equal.

3. A combined reinforcement method for repairing cracks in the secondary lining of a tunnel according to claim 2, characterized in that: There are a plurality of anchor cables (1), each of which is a high-strength steel strand with a nominal diameter of 15-17 mm and a tensile strength of 1800-1900 MPa; the tensioning force of each anchor cable (1) is 120-130 kN, and the hole diameter is 105-115 mm.

4. A combined reinforcement method for repairing cracks in the secondary lining of a tunnel according to claim 1, characterized in that: In step S2, the loose surrounding rock behind the lining is backfilled and grout-reinforced using the steel pipe (2).

5. A combined reinforcement method for repairing cracks in the secondary lining of a tunnel according to claim 4, characterized in that: The steel flower tube (2) is 1.5-2.5 m long and 40-45 mm in diameter, and the spacing and row spacing of the steel flower tube (2) are equal.

6. A combined reinforcement method for repairing cracks in the secondary lining of a tunnel according to claim 2 or 5, characterized in that: The spacing and row spacing of the anchor cables (1) are greater than the spacing and row spacing of the steel flower tubes (2).

7. A combined reinforcement method for repairing cracks in the secondary lining of a tunnel according to claim 1, characterized in that: The step S3 specifically comprises the following steps: Step S31: concrete surface treatment; Step S32: pre-coating primer; Step S33: scraping putty; Step S34: laying carbon fiber cloth; Step S35: maintenance; Step S36: Apply special paint.

8. A combined reinforcement method for repairing cracks in the secondary lining of a tunnel according to claim 7, characterized in that: The step S34 comprises the following steps: Step S341: double-layer steel mesh lining or sprayed steel fiber lining is set at the location where the block falls, and 1-2% steel fiber sprayed concrete is used to repair the crack location; Step S342: embedding carbon fiber cloth into the inner surface of the tunnel lining for reinforcement; Step S343: The carbon fiber cloth is fully laid along the circumference of the tunnel.

9. A combined reinforcement method for repairing cracks in the secondary lining of a tunnel according to claim 8, characterized in that: In step S343, when the carbon fiber cloth is fully laid along the circumferential direction of the tunnel, the width of the circumferential belt is 1-2m, and one belt is laid every 1.5-3.0m in the longitudinal direction.

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