A construction method suitable for rapid repair of tunnel lining structure

Abstract

The present disclosure provides a construction method suitable for the rapid repair of tunnel lining structures, which relates to the technical field of tunnel engineering repair, and can quickly repair damaged tunnels and restore traffic order as soon as possible. The construction method includes: dismantling the ancillary facilities in the damaged area; cleaning the damaged concrete in the damaged area until fresh concrete is exposed; first implanting steel bars on the surface of the fresh concrete, and then using the ends of the steel bars to hang mesh to form a support skeleton, and then spraying polypropylene fiber concrete on the support skeleton; constructing a finishing layer on the surface of the polypropylene fiber concrete, the finishing layer is connected and coordinated with the original decoration of the undamaged area, and the finishing layer also makes up for the lack of flatness of the polypropylene fiber concrete; repairing the road surface and ancillary facilities in the damaged area. The construction equipment selected in the present disclosure can be put into operation immediately after arriving at the site, avoiding time-consuming preparation period for temporary construction, and compressing the repair period to the shortest.

Description

Technical Field

[0001] The present disclosure relates to the field of tunnel construction, and in particular to a construction method suitable for rapid repair of tunnel lining structures. Background Art

[0002] Highway tunnels are passages used exclusively for automobile transportation. The construction of tunnels plays an important role in improving the technical status of highways, shortening operating distances, increasing transportation capacity, and reducing accidents.

[0003] Tunnel disasters include sudden damage. There are three main reasons for sudden damage in tunnels: (1) caused by fire in the vehicle itself or collision between two vehicles; (2) caused by explosion or leakage of vehicles transporting dangerous goods; and (3) caused by failure of electrical equipment in the tunnel.

[0004] After a sudden damage accident occurs in a highway tunnel, in addition to the loss of life and property to varying degrees, it also faces the negative impact caused by traffic interruption and the pressure of urgent repair time. At the same time, since the damage accident of a highway tunnel is a sudden accident, in order to restore traffic order as soon as possible, the time limit for post-disaster repair has been repeatedly compressed.

[0005] Based on this, there is an urgent need to provide a construction method suitable for the rapid repair of tunnel lining structures to meet the special requirements of this type of special project. Summary of the invention

[0006] The embodiment of the present invention provides a construction method suitable for rapid repair of a tunnel lining structure. After the damaged concrete is cleaned and a rough surface is formed, polypropylene fiber C30 concrete is sprayed to achieve the purpose of conveniently and rapidly reinforcing the damaged structure.

[0007] To achieve the above object, the embodiments of the present invention adopt the following technical solutions:

[0008] The present invention discloses a construction method suitable for rapid repair of a tunnel lining structure. The tunnel is divided into a damaged area and an undamaged area. The construction method comprises the following steps:

[0009] Step 1: dismantle the ancillary facilities in the damaged area;

[0010] Step 2, cleaning the damaged concrete in the damaged area until fresh concrete is exposed;

[0011] Step 3: implant steel bars on the surface of the fresh concrete, and then use the ends of the steel bars to hang mesh sheets to form a support skeleton, and then spray polypropylene fiber concrete on the support skeleton, so that the polypropylene fiber concrete is flush with the concrete surface of the undamaged area;

[0012] Step 4: constructing a finishing layer on the surface of the polypropylene fiber concrete, wherein the finishing layer is in smooth connection with and coordinated with the original decoration of the undamaged area, and the finishing layer can also make up for the lack of flatness of the polypropylene fiber concrete;

[0013] Step 5: Repair the road surface and ancillary facilities in the damaged area.

[0014] In some embodiments, the auxiliary facilities of step 1 include a cable tray, a cable and a lamp. The cable tray and the lamp are installed on the side wall of the tunnel, and the cable is installed in a cable groove at the bottom of the side wall. The cable extends from the cable groove to the cable tray and is connected to the lamp.

[0015] The step 1 specifically comprises: removing the cable bracket, cables and lamps in the damaged area, and clearing the cable trench in the damaged area;

[0016] The step five specifically includes: repairing the road surface and cable trench in the damaged area, and repairing the cable brackets, cables and lamps in the damaged area.

[0017] In some embodiments, the step 2 is specifically:

[0018] Use a special mining milling machine to clean the damaged concrete in the damaged area, and chisel and clean the exposed fresh concrete;

[0019] During the cleaning and roughening process, construction machinery and personnel should be parked in the downwind area.

[0020] In some embodiments, the steel bar in step three is a threaded steel bar, and the threaded steel bar is connected to the fresh concrete by an adhesive;

[0021] The step 3 of implanting steel bars into fresh concrete comprises:

[0022] Drill holes at the positions of the fresh concrete corresponding to the steel bars and inject adhesive, then insert the steel bars, and after the adhesive cures, the steel bars and the fresh concrete are bonded together.

[0023] In some embodiments, the adhesive is modified epoxy-type Class A adhesive, the splitting tensile strength of the modified epoxy-type Class A adhesive is ≥8.5MPa, the flexural strength is ≥50MPa, the compressive strength is ≥60MPa, and the bonding strength between the modified epoxy-type Class A adhesive and fresh concrete is ≥12.0MPa.

[0024] In some embodiments, a mesh hanging groove is reserved at the end of the steel bar in step three, and the mesh in step three is hung in the mesh hanging groove.

[0025] In some embodiments, step three specifically includes:

[0026] implanting steel bars on the surface of the fresh concrete;

[0027] Use a positioning frame to control the insertion depth of each steel bar to ensure that the mesh hanging groove of each steel bar is consistent with the concrete surface clearance of the undamaged area;

[0028] The mesh hanging grooves of the steel bars are used to hang mesh to form a support skeleton;

[0029] Spraying polypropylene fiber concrete onto the supporting skeleton;

[0030] The polypropylene fiber concrete maintains clearance with the concrete surface of the undamaged area.

[0031] In some embodiments, the step three of spraying polypropylene fiber concrete onto the support frame includes:

[0032] A vehicle with a work platform is driven to the damaged area and secured;

[0033] Construction workers stand on a work platform to spray polypropylene fiber concrete;

[0034] The spraying sequence is from the tunnel side wall to the tunnel vault, and the construction workers construct 5±0.5m each time along the driving direction of the tunnel.

[0035] In some embodiments, the raw materials of polypropylene fiber concrete include cement and polypropylene fibers;

[0036] The cement shall be silicate cement or ordinary silicate cement, with a cement grade of at least 42.5;

[0037] The volume content of the polypropylene fiber is 0.20% of the volume of the concrete, and the fiber type of the polypropylene fiber is bundled monofilament.

[0038] In some embodiments, the finishing layer in step 4 is divided into two layers, the inner layer is a waterproof coating layer, the thickness of the waterproof coating layer is 0.7-1.0 mm; the outer layer is a flame retardant putty powder layer, the spraying thickness of the flame retardant putty powder layer is 1.0-1.5 mm;

[0039] The step 5 of repairing the road surface in the damaged area includes:

[0040] Milling of 5±0.5cm pavement for damaged pavement;

[0041] Newly pave 5±0.5cm asphalt concrete for restoration.

[0042] In the present disclosure, there are at least the following technical effects or advantages:

[0043] 1. The construction equipment selected in the embodiments of the present invention can be put into operation immediately after arriving at the site, so as to avoid the construction preparation period occupying the construction period and shorten the repair period to the shortest.

[0044] 2. The present invention abandons the traditional cast-in-place concrete lining and uses polypropylene fiber C30 shotcrete to reinforce the damaged parts. The purpose is to shorten the construction preparation period, quickly reinforce and strengthen, and pursue the best cost-effectiveness. It can also play a role in silencing and reducing noise in the tunnel.

[0045] 3. The present invention uses a special mining milling machine to clean and roughen the carbonized concrete on the surface of the tunnel secondary lining, which is convenient for rapid construction and forms a rough surface, which is beneficial to the subsequent structural adhesion; during construction, the construction machinery and workers are required to stop in the downwind area.

[0046] 4. The present invention adopts a positioning frame to control the insertion depth of the rebar, which solves the problem of unevenness and uneven damage in the suddenly damaged tunnel and ensures that the thickness of the protective layer meets the requirements of the specifications.

[0047] 5. The present invention adopts sprayed polypropylene fiber C30 concrete, which is convenient for compressing the construction preparation period, quickly forming strength and pursuing the best cost performance, while playing the effect of silencing and reducing noise in the tunnel.

[0048] 6. The present invention restores the coating of the suddenly damaged section in the tunnel, which not only makes up for the lack of flatness of the shotcrete, but also makes the decoration of the repaired tunnel coordinated with that of the normal section of the tunnel, meets the psychological needs of drivers and passengers, and overcomes the psychological shadow brought to passengers by the post-disaster tunnel. BRIEF DESCRIPTION OF THE DRAWINGS

[0049] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments of the present invention or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0050] Figure 1 A flow chart of a construction method adapted for rapid repair of a tunnel lining structure according to some embodiments of the present disclosure;

[0051] Figure 2 This is a diagram of the damaged state of the sudden damaged tunnel (part a is a diagram of the damaged state of the lining structure, and part b is a diagram of the overall damaged state of the tunnel project);

[0052] Figure 3 The status diagram of the construction method (part a is a diagram showing the milling machine cleaning and roughening the carbonized concrete on the secondary lining surface, part b is a diagram showing the damaged lining structure after cleaning and roughening, part c is a schematic diagram of the shotcrete construction operation, and part d is a diagram showing the completion of the repair of the suddenly damaged tunnel);

[0053] Figure 4This is a schematic diagram of the structure for post-disaster repair of a suddenly damaged tunnel;

[0054] Figure 5 Schematic diagram of the construction for embedding steel bars into the surface of fresh concrete;

[0055] Figure 6 This is a schematic diagram of the reinforcement structure;

[0056] Figure 7 This is a schematic diagram of the positioning tire frame structure;

[0057] Figure 8 This is a schematic diagram of the coating structure inside the tunnel that was suddenly damaged;

[0058] Fig. 9 Cross-road diagram for repairing a sudden damaged tunnel using conventional methods;

[0059] Fig.10 A cross-section diagram for repairing a sudden damaged tunnel using the disclosed construction method;

[0060] Figure numerals: 100, original lining concrete structure layer; 200, new sprayed concrete structure layer; 300, embedded reinforcement; 400, mesh; 500, mesh hanging groove; 1, lining profile edge band; 2, spokes; 3, fine-tuning screw; 4, fixing bracket; 5, flame-retardant putty powder; 6, waterproof coating. DETAILED DESCRIPTION

[0061] The present disclosure is described in detail below in conjunction with the various embodiments shown in the accompanying drawings, but it should be noted that these embodiments are not limitations of the present disclosure, and any equivalent transformations or substitutions in functions, methods, or structures made by ordinary technicians in the field based on these embodiments are all within the scope of protection of the present disclosure.

[0062] The embodiment of the present disclosure provides a construction method suitable for rapid repair of tunnel lining structure. The tunnel is divided into a damaged area and an undamaged area. Figure 1 , the construction method comprises the following steps:

[0063] Step 1: Remove the ancillary facilities in the damaged area (see Figure 2 ,tear down Figure 2 The cable bracket and cable in part a. The uneven part in part a is the damaged area. Figure 2 The cable trench in part b, the original facing layer in the damaged area of ​​part b is partially damaged and peeled off);

[0064] Step 2: Clean the damaged concrete in the damaged area until fresh concrete is exposed; (See Figure 3 , Figure 3Part a in the middle is a state diagram of cleaning the damaged concrete in the damaged area. The area enclosed by the box in part a indicates that the milling machine is cleaning the damaged concrete on the secondary lining surface and roughening it. Figure 3 Part b in the middle is fresh concrete after being roughened by a milling machine);

[0065] Step 3: First, implant steel bars on the surface of fresh concrete, and then use the ends of the steel bars to hang mesh to form a support skeleton. Next, spray polypropylene fiber concrete on the support skeleton. The polypropylene fiber concrete covers the mesh and is flush with the concrete in the undamaged area; (Please refer to Figure 3 , Figure 3 The right half of part c shows the construction worker standing in the bucket of the loader spraying polypropylene fiber concrete after taking safety precautions. The lower half of part c shows the completed polypropylene fiber concrete, and the mesh can be vaguely seen in the upper half of part c);

[0066] Step 4: construct a finishing layer on the surface of the polypropylene fiber concrete. The finishing layer is connected and coordinated with the original decoration of the undamaged area. The finishing layer can also make up for the inherent deficiency of the flatness of the polypropylene fiber concrete.

[0067] Step 5: Repair the road surface and ancillary facilities in the damaged area (see Figure 3 , Figure 3 Part d in the middle is a schematic diagram of the repaired tunnel).

[0068] The suddenly damaged tunnel in the embodiment of the present disclosure generally refers to the tunnel after the damage. After the tunnel is damaged, the area around the fire is generally called the damaged area, the tunnel decoration layer in the damaged area is destroyed, and the lining concrete is damaged. The area that is not damaged in the suddenly damaged tunnel is called the undamaged area, and the construction method of the present disclosure does not perform construction treatment on the undamaged area.

[0069] "Technical Specifications for Highway Tunnel Reinforcement" (JTG / T5440-2018) 11.2.3.3 states: According to the degree of damage to the fire-damaged section of the tunnel and the original structure, the secondary masonry structure of the severely damaged section shall be completely dismantled and replaced; the moderately damaged section and the slightly damaged section are only surface damaged, and the surface is leveled to treat the masonry appearance and improve the durability of the damaged surface concrete; the road surface burned by the fire is treated by overall removal and resurfacing. For the lining structure of the damaged section, the burned concrete on the lining surface needs to be removed and cleaned.

[0070] The damaged concrete mentioned above can be the tunnel surface damage or fallen decorative layer, the tunnel wall cracked and fallen tiles, or the tunnel decorative layer polluted by smoke; of course, it can also be the peeling tunnel secondary lining concrete, for example: the maximum peeling thickness of some secondary lining concrete is 15cm, and the damage to the secondary lining concrete in other sections is relatively light, mainly local damage.

[0071] The ancillary facilities in the above step 1 include cable brackets, cables and lamps. The cable brackets and lamps are installed on the side walls of the tunnel. The cables are installed in the cable grooves at the bottom of the side walls. The cables extend from the cable grooves to the cable brackets and are connected to the lamps. Based on the above description, a construction method suitable for rapid repair of tunnel lining structures disclosed in the present invention includes the following steps:

[0072] Step 1 specifically includes: removing the cable trays, cables and lamps in the damaged area, and clearing the cable trench in the damaged area;

[0073] Step 2: Clean the damaged concrete in the damaged area until fresh concrete is exposed;

[0074] Step 3: First, implant steel bars on the surface of fresh concrete, and then use the ends of the steel bars to hang mesh to form a support skeleton. Next, spray polypropylene fiber concrete on the support skeleton. The polypropylene fiber concrete covers the mesh and is flush with the concrete in the undamaged area.

[0075] Step 4: construct a finishing layer on the surface of the polypropylene fiber concrete. The finishing layer is connected and coordinated with the original decoration of the undamaged area. The finishing layer can also make up for the inherent deficiency of the flatness of the polypropylene fiber concrete.

[0076] Step 5: Repair the road surface and cable trenches in the damaged area, and repair the cable trays, cables and lamps in the damaged area.

[0077] In the embodiment of the present disclosure, step two specifically includes: using a mining-specific milling machine to clean the damaged concrete in the damaged area, and roughening the fresh concrete exposed after cleaning, and during the cleaning and roughening process, the construction machinery and personnel are parked in the downwind area.

[0078] There are two main methods for chiseling the damaged surface of the original lining and cleaning the carbonized concrete. The first method is manual chiseling, that is, manually setting up a simple stand and using a handheld pneumatic pick to remove it point by point and section by section. It has the disadvantages of low efficiency, high labor intensity, and serious damage to occupational health. The second method is to replace the excavator bucket with a breaker and chisel it point by point and section by section. This method has low efficiency and the cleaned molding surface is smooth, which is not conducive to the adhesion of the later shotcrete. This embodiment uses an excavator to carry a special mining milling machine to clean the damaged surface and damaged concrete, which can give play to the common advantages of the excavator's "flexibility" and the milling machine's "instant assembly and immediate construction". At the same time, the carbonized concrete can be cleaned into a rough surface to facilitate the adhesion of the shotcrete.

[0079] In addition, this embodiment emphasizes that since a certain amount of ash will be generated during the construction of the mining milling machine, it may affect the occupational health of the workers under the influence of natural wind, so the construction machinery and workers are required to be parked in the downwind area during the construction process.

[0080] In the embodiment of the present disclosure, the steel bar in step 3 is a threaded steel bar, and the threaded steel bar is connected to the fresh concrete by an adhesive. The step 3 of implanting the steel bar on the surface of the fresh concrete includes: drilling holes at positions of the fresh concrete corresponding to the steel bar and injecting adhesive, then inserting the steel bar, and bonding the steel bar and the fresh concrete as one after the adhesive is cured.

[0081] Due to the different degrees of damage to the tunnel lining structure, the cleaned surface also appears wavy. In addition, compared with cast concrete, the surface flatness of shotcrete is inherently insufficient. On this basis, how to ensure the uniform thickness of the steel bar protective layer and meet the tunnel clearance requirements has become a difficult problem for the builders.

[0082] Conventional construction methods use a simple driving method to insert the embedded steel bars (embedded steel bars are short for embedded steel bars) to different depths; the mesh is tied or welded, which is labor-intensive and cannot guarantee quality. More seriously, conventional construction methods cause the thickness of the steel bar protective layer to be uneven and the surface flatness of the shotcrete to be uneven.

[0083] For the above problems, please refer to Figure 6 and Figure 7 The design concept of this embodiment is: 1. First, make a positioning frame, and control the insertion depth of the top end (point A) of the embedded reinforcement 300 to meet the requirements (L1+L2=30cm, L1 and L2 are both variable), so as to control the points B, C and D of the embedded reinforcement 300 in disguised form; 2. Secondly, through the mesh hanging groove 500 on the embedded reinforcement 300, the mesh 400 is hung accurately; 3. The thickness of the protective layer of the new sprayed concrete structure layer 200 is controlled to reach 5cm through the mesh 400 again, and the surface flatness of the new sprayed concrete structure layer 200 is kept in compliance with the requirements; 4. Finally, the coating is restored in the tunnel, the purpose is to make up for the lack of flatness of the sprayed concrete and play a visual guidance role.

[0084] The above design concept is applied to the construction method for rapid repair of tunnel lining structure in this embodiment, and step three specifically includes:

[0085] Implanting steel bars into the surface of fresh concrete;

[0086] Use a positioning frame to control the insertion depth of each steel bar to ensure that the mesh hanging groove of each steel bar is consistent with the concrete surface clearance of the undamaged area;

[0087] Use the mesh hanging grooves of the steel bars to hang the mesh to form a support skeleton;

[0088] Spraying polypropylene fiber concrete onto the supporting skeleton;

[0089] Polypropylene fiber concrete covers the mesh and is flush with the concrete in the undamaged area.

[0090] See also Figure 7 The above-mentioned positioning tire frame includes a lining profile edge band 1, a plurality of spokes 2, a fine-tuning screw 3, and a fixed bracket 4. The fine-tuning screw 3 is connected to the fixed bracket 4. The lining profile edge band 1 is connected to the fixed bracket 4 through the plurality of spokes 2. The lining profile edge band 1, the plurality of spokes 2 and the fixed bracket 4 are assembled into a structure similar to a "folding fan", wherein each spoke 2 is equivalent to the skeleton of the folding fan structure, one end of the plurality of spokes 2 is hinged, and the other ends of the plurality of spokes 2 are respectively connected to different points of the lining profile edge band 1, and the lining profile edge band 1 is foldable.

[0091] The positioning frame is like a "fan", which can be closed when not in use. When in use, the height of the fixed bracket 4 is adjusted to the center of the designed clearance section of the tunnel lining, the spokes 2 and the lining contour edge band 1 are opened, and the left and right sides of the frame are made to meet the superelevation requirements of the road surface by fine-tuning the screw 3; the top of the spoke 2 is deducted from the thickness of the steel bar protective layer (5cm) to obtain point A, which is the tail end of the embedded rebar, and the embedded rebar is accurately driven into the original lining in this way.

[0092] In addition, the anchor bars in this embodiment preferably use threaded steel bars with a diameter of 22 mm and modified epoxy-type Class A adhesive (splitting tensile strength ≥8.5 MPa, flexural strength ≥50 MPa, compressive strength ≥60 MPa, and bonding strength with concrete ≥12.0 MPa), which can also achieve the purpose of fast construction and optimal cost performance (the gripping strength of threaded steel bars).

[0093] See also Figure 5 and Figure 6 The mesh hanging groove 500 is reserved at the end of the steel bar in step 3, and the mesh 400 in step 3 is hung on the mesh hanging groove 500. In this embodiment, after the embedded steel bar 300 is driven into the original lining concrete structure layer 100, the mesh hanging groove 500 reserved at the tail end of the embedded steel bar 300 can be used to hang the mesh 400 on the embedded steel bar 300 (the mesh size of the mesh 400 is matched with the spacing between the embedded steel bars).

[0094] In this embodiment, after the mesh is hung on the embedded reinforcement, the shotcrete construction begins immediately. Conventional shotcrete construction requires the construction of a simple workbench or the activation of a wet spraying manipulator, both of which require a certain construction preparation period. However, this embodiment uses a loader bucket as the operating platform, which can minimize the construction preparation period, thereby ensuring that the overall construction period is within the plan (15 days). It should be emphasized that since a certain amount of ash will be generated during the construction of the mine-specific milling machine, it may affect the occupational health of the staff under the action of natural wind, so the construction machinery and staff are required to be parked in the downwind area during the construction process.

[0095] After the shotcrete construction is completed, the painting inside the tunnel is restored to ensure that the shotcrete lining is coordinated with the original decoration, make up for the inherent deficiency of the shotcrete flatness, and play a visual guidance role. In addition, the materials used for the painting inside the tunnel in this embodiment are divided into two layers, the outer layer is a flame-retardant putty powder with a spraying thickness of 1.0 to 1.5 mm, and the inner layer is a waterproof coating, which is sprayed twice with a thickness of 0.7 to 1.0 mm, which can also achieve the purpose of fast construction and optimal cost performance.

[0096] In an embodiment of the present disclosure, step three of spraying polypropylene fiber concrete onto the support frame includes:

[0097] A vehicle with a work platform is driven to the damaged area and secured;

[0098] Construction workers stand on a work platform to spray polypropylene fiber concrete;

[0099] The spraying sequence is from the tunnel side wall to the tunnel vault, and the construction workers construct 5±0.5m each time along the driving direction of the tunnel.

[0100] The vehicle with the work platform in this embodiment can be an excavator with protective measures, and the construction personnel and the protective measures are all located in the bucket of the excavator. After the construction personnel have taken protective measures, they stand in the bucket to spray polypropylene fiber concrete, which has the advantage of convenient construction. The vehicle with the work platform in this embodiment can also be a four-wheel truck with the work platform. The four-wheel truck is driven to the damaged area, the bottom end of the work platform is supported on the tunnel ground, the frame of the work platform is fixed on the top surface of the four-wheel truck, and the work platform of the work platform faces the top of the tunnel. After the construction personnel have taken protective measures, they stand on the work platform to spray polypropylene fiber concrete.

[0101] In an embodiment of the present disclosure, the raw materials of polypropylene fiber concrete include cement and polypropylene fibers;

[0102] The cement shall be silicate cement or ordinary silicate cement, with a cement grade of at least 42.5;

[0103] The volume content of the polypropylene fiber is 0.20% of the volume of the concrete, and the fiber type of the polypropylene fiber is bundled monofilament.

[0104] Based on the above description, the present invention discloses a construction method suitable for rapid repair of a tunnel lining structure, comprising the following steps:

[0105] Step 1: Remove the cable trays, cables and lamps in the damaged area, and clear the cable trench in the damaged area;

[0106] Step 2: Use a special mining milling machine to clean the damaged concrete in the damaged area and chisel the fresh concrete exposed after cleaning. During the cleaning and chiseling process, the construction machinery and personnel should be parked in the downwind area;

[0107] Step 3: First, threaded steel bars are implanted on the surface of fresh concrete (the process of implanting threaded steel bars on the surface of fresh concrete is: drilling holes at the positions of the steel bars in the fresh concrete and injecting adhesive, then inserting the steel bars, and bonding the steel bars and fresh concrete together after the adhesive solidifies), and then the threaded steel bars are used to hang the mesh, and then polypropylene fiber concrete is sprayed from the surface of the mesh onto the fresh concrete, and the polypropylene fiber concrete covers the mesh and is flush with the concrete in the undamaged area;

[0108] Step 4: construct a finishing layer on the surface of the polypropylene fiber concrete. The finishing layer is connected and coordinated with the original decoration of the undamaged area, and the finishing layer also makes up for the lack of flatness of the polypropylene fiber concrete;

[0109] Step 5: Repair the road surface and cable trenches in the damaged area, and repair the cable trays, cables and lamps in the damaged area.

[0110] In the embodiments of the present disclosure, please refer to Figure 8 The finishing layer of step four is divided into two layers, the inner layer is a waterproof coating 6, one layer on the bottom and one layer on the surface, and the thickness of the waterproof coating layer is 0.7-1.0 mm; the outer layer is a flame retardant putty powder layer 5, and the spraying thickness of the flame retardant putty powder layer 5 is 1.0-1.5 mm.

[0111] Step 5: Repair the damaged area of ​​the road, including:

[0112] Milling 5±0.5cm of damaged road surface;

[0113] Newly pave 5±0.5cm asphalt concrete for restoration.

[0114] After the above lining structure repair construction is completed, the damaged road surface and ancillary facilities are repaired immediately. This embodiment adopts the following repair measures for the damaged road surface: 5 cm of the road surface is generally milled on the damaged road section, and then 5 cm of asphalt concrete is newly laid to restore it.

[0115] A certain highway tunnel is a separated tunnel with a designed speed of 80 km / h. The left line is 3456m long and the right line is 3343m long. It is a curved extra-long tunnel with a longitudinal slope of 2.467%. The tunnel has a clear height of 5m and a clear width of 10.25m.

[0116] At 19:50 on the night of July 12, 2020, a six-axle semitrailer caught fire at 617 meters (YK0+617) of the right entrance of the tunnel, killing two drivers and passengers. The accident also damaged some electromechanical equipment, cables, bridges, and lighting fixtures in the tunnel from K0+617 to K0+835 (218 meters long). The concrete of the tunnel's secondary lining (originally designed as C25 plain concrete, 35 cm thick) was severely peeled off, and the tiles on the tunnel wall exploded and fell off. The accident caused traffic disruption and seriously affected local social production, life, and social stability.

[0117] In order to restore traffic order as soon as possible, the local government and industry authorities held an emergency meeting and required that the tunnel repair project adopt innovative technologies and shorten the construction period to 15 days.

[0118] According to the conventional construction method, the main procedures of this repair project are: ① The construction unit enters the site to build temporary structures such as concrete mixing plants and steel processing plants; ② The damaged cable brackets, lamps and other equipment are dismantled; ③ The damaged and damaged concrete on the lining surface is cleaned by using an excavator carrying a breaker, and the damaged cable trench is cleaned at the same time; ④ The workbench is set up, the lines are laid out manually, the points are tied manually (or welded), Φ22 steel bars are implanted, and Φ10 mesh sheets are hung; ⑤ The hydraulic lining trolley is assembled, the delivery pump is installed, and the molded concrete is poured; ⑥ The trolley is demolded and shifted, and the concrete is cured; ⑦ The painting inside the tunnel is restored; ⑧ The auxiliary facilities such as the side ditch and cable trench are restored; ⑨ The road surface, electromechanical, signs and markings are repaired; ⑩ Traffic is opened and traffic is restored... With this construction method, the construction cost increases by at least 50% and the construction period takes at least 6 months. For details, see Fig. 9 .

[0119] Based on this, this embodiment provides a construction method suitable for the rapid repair of tunnel lining structures: (1) Dismantle damaged cable brackets, lamps and other equipment; (2) Use a mining-specific milling machine to clean the damaged surface of the original lining 100 and the damaged concrete, and clean the damaged cable trench at the same time; (3) Use a homemade positioning tire frame to control the thickness of the concrete protective layer, accurately drive in the embedded rebar 300, and hang the mesh 400; use the loader bucket as a construction platform, and spray polypropylene fiber C30 concrete for reinforcement; (4) Restore the painting inside the tunnel to ensure that the sprayed concrete lining is coordinated with the original decoration; (5) Repair the road surface and ancillary facilities; (6) Open traffic and resume traffic. The suddenly damaged tunnel lining structure repaired by this embodiment has achieved the goal of opening traffic in the shortest time (see for details). Fig.10 ), resume traffic, and optimize the construction period and construction cost.

[0120] This embodiment adopts the following repair measures for the damaged road surface: 5 cm of the road surface is generally milled on the damaged road section, and then 5 cm of asphalt concrete is newly laid to restore it.

[0121] The series of detailed descriptions listed above are only specific descriptions of feasible implementation methods of the present disclosure. They are not intended to limit the protection scope of the present disclosure. Any equivalent implementation methods or changes that do not deviate from the technical spirit of the present disclosure should be included in the protection scope of the present disclosure.

[0122] It is obvious to those skilled in the art that the present disclosure is not limited to the details of the exemplary embodiments described above, and that the present disclosure can be implemented in other specific forms without departing from the spirit or essential features of the present disclosure. Therefore, the embodiments should be regarded as exemplary and non-restrictive from all points of view, and the scope of the present disclosure is defined by the appended claims rather than the above description, and it is intended that all changes falling within the meaning and scope of the equivalent elements of the claims are included in the present disclosure. Any reference numeral in a claim should not be regarded as limiting the claim to which it relates.

[0123] In addition, it should be understood that although the present specification is described according to implementation modes, not every implementation mode contains only one independent technical solution. This description of the specification is only for the sake of clarity. Those skilled in the art should regard the specification as a whole. The technical solutions in each embodiment may also be appropriately combined to form other implementation modes that can be understood by those skilled in the art.

Claims

1. A construction method suitable for rapid repair of tunnel lining structure, characterized in that: The tunnel is divided into damaged and undamaged areas, and the construction method includes the following steps: Step 1: dismantle the ancillary facilities in the damaged area; Step 2, cleaning the damaged concrete in the damaged area until fresh concrete is exposed; Step 3: first implant steel bars on the surface of the fresh concrete, then use the ends of the steel bars to hang mesh sheets to form a support skeleton, and then spray polypropylene fiber concrete on the support skeleton, so that the polypropylene fiber concrete is flush with the concrete surface of the undamaged area; Step 4: constructing a finishing layer on the surface of the polypropylene fiber concrete, wherein the finishing layer is smoothly connected and coordinated with the original decoration of the undamaged area, and the finishing layer also makes up for the lack of flatness of the polypropylene fiber concrete; Step 5: Repair the road surface and ancillary facilities in the damaged area; The step three specifically includes: implanting steel bars on the surface of the fresh concrete; Use a positioning frame to control the insertion depth of each steel bar to ensure that the mesh hanging groove of each steel bar is consistent with the concrete surface clearance of the undamaged area; The mesh hanging grooves of the steel bars are used to hang mesh to form a support skeleton; Spraying polypropylene fiber concrete onto the supporting skeleton; The polypropylene fiber shotcrete maintains a clearance consistent with the concrete surface of the undamaged area; The positioning tire frame includes a lining profile edge belt, a plurality of spokes, a fine-tuning screw, and a fixed bracket, the fine-tuning screw is connected to the fixed bracket, the lining profile edge belt is connected to the fixed bracket through the plurality of spokes, the lining profile edge belt, the plurality of spokes and the fixed bracket are assembled into a structure similar to a folding fan, wherein each spoke is equivalent to the skeleton of the folding fan structure, one end of the plurality of spokes is hinged, and the other ends of the plurality of spokes are respectively connected to different points of the lining profile edge belt, and the lining profile edge belt is foldable; The step 3 of spraying polypropylene fiber concrete onto the support frame comprises: A vehicle with a work platform is driven to the damaged area and secured; Construction workers stand on a work platform to spray polypropylene fiber concrete; The spraying sequence is from the tunnel side wall to the tunnel vault, and the construction workers construct 5±0.5m each time along the driving direction of the tunnel.

2. The construction method according to claim 1, characterized in that: The ancillary facilities in step 1 include cable brackets, cables and lamps. The cable brackets and lamps are installed on the side walls of the tunnel. The cables are installed in cable trenches at the bottom of the side walls. The cables extend from the cable trenches to the cable brackets and are connected to the lamps. The step 1 specifically comprises: removing the cable bracket, cables and lamps in the damaged area, and clearing the cable trench in the damaged area; The step five specifically includes: repairing the road surface and cable trench in the damaged area, and repairing the cable brackets, cables and lamps in the damaged area.

3. The construction method according to claim 1, characterized in that: The step 2 is specifically as follows: Using a mining milling machine to clean the damaged concrete in the damaged area, and roughening and cleaning the exposed fresh concrete; During the cleaning and roughening process, construction machinery and personnel should be parked in the downwind area.

4. The construction method according to claim 1, characterized in that: The steel bar in step 3 is a threaded steel bar, and the threaded steel bar is connected to the fresh concrete by an adhesive; The step 3 of implanting steel bars on the surface of the fresh concrete comprises: Drill holes at the positions of the steel bars on the surface of the fresh concrete and inject adhesive, then insert the steel bars, and after the adhesive cures, the steel bars and the fresh concrete are bonded together.

5. The construction method according to claim 4, characterized in that: The adhesive used is modified epoxy Class A adhesive. The splitting tensile strength of the modified epoxy Class A adhesive is ≥8.5MPa, the flexural strength is ≥50MPa, and the compressive strength is ≥60MPa. The bonding strength between the modified epoxy Class A adhesive and fresh concrete is ≥12.0MPa.

6. The construction method according to claim 1, characterized in that: A mesh hanging groove is reserved at the end of the steel bar in step three, and the mesh in step three is hung in the mesh hanging groove.

7. The construction method according to claim 1, characterized in that: The raw materials of polypropylene fiber concrete include cement and polypropylene fiber; The cement shall be silicate cement or ordinary silicate cement, with a cement grade of at least 42.5; The volume content of the polypropylene fiber is 0.20% of the volume of the concrete, and the fiber type of the polypropylene fiber is bundled monofilament.

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