Tunnel bottom grouting reinforcement and lining crack repair method

Abstract

The invention discloses a tunnel bottom grouting reinforcement and lining crack repair method, and belongs to the technical field of tunnel repair. Comprising a stage A and a stage B, stage A, tunnel bottom grouting reinforcement is conducted, and tunnel bottom sedimentation is prevented; stage B, lining crack repair is conducted after tunnel bottom grouting reinforcement in the stage A is completed, inspection is qualified, and lining crack repair is conducted after inspection is qualified; the technical problems that in a traditional tunnel repairing technology, only lining cracks are repaired, reinforcement and sedimentation prevention are not conducted on the tunnel bottom, no specific treatment method is conducted according to the sizes of different cracks, and the probability of occurrence of the cracks is large are solved.

Description

Technical Field

[0001] The invention relates to the technical field of tunnel repair, in particular to a method for grouting reinforcement of a tunnel bottom and repairing lining cracks. Background Art

[0002] Tunnels are often opened in mountainous environments with relatively complex environments. The natural conditions in mountainous areas (hydrogeological conditions, topographic conditions, climatic conditions and adverse geological effects, etc.) will damage the structure of the tunnel. The structural damage of the tunnel is mostly reflected in the sinking of the foundation and the rupture of the tunnel arch. In order to prevent the tunnel from being further damaged and causing safety hazards, the tunnel needs to be reinforced and repaired. The tunnel crack injection repair method for tunnel engineering with the publication number of CN115788508A provides a tunnel crack injection repair method for tunnel engineering, using a grinding and cleaning machine to perform grinding and cleaning operations, driving a mobile lifting module to the bottom of the tunnel crack, and raising the grinding and cleaning module to a suitable position from the crack surface wall through a lifting bracket until the grinding disc and the shield are tightly fitted with the crack surface wall, and smoothly carry out grinding, cleaning and vacuuming operations, and adjust the position of the lower end mobile lifting module at any time according to the direction of the crack, and then carry out subsequent pressure testing and grouting operations. Compared with the traditional method, this technical solution drills the grouting holes at an angle, and the structural adhesive can directly enter the deepest part of the gap during the grouting operation, so that the inside of the gap is full and full without air, meeting the design construction requirements and acceptance standards, and reducing the probability of subsequent rework, extending the service life of the tunnel. In the above-mentioned tunnel repair technologies, only the lining cracks are repaired, and the tunnel bottom is not reinforced to prevent settlement, and no specific treatment methods are used according to the size of different cracks, so the probability of cracks occurring is high. Summary of the invention

[0003] The purpose of the present invention is to provide a method for grouting reinforcement of tunnel bottom and repairing lining cracks in view of the above problems, so as to solve the technical problems that in traditional tunnel repair technology, only lining cracks are repaired, and the tunnel bottom is not reinforced to prevent settlement, and there is no specific treatment method according to the size of different cracks, resulting in a high probability of cracks occurring.

[0004] In order to achieve the above object, the technical solution adopted by the present invention is:

[0005] A method for tunnel bottom grouting reinforcement and lining crack repair, comprising the following stages A and B;

[0006] Phase A: Grouting reinforcement at the tunnel bottom to prevent tunnel bottom settlement;

[0007] Phase B: Lining crack repair, which is carried out after the tunnel bottom grouting reinforcement in Phase A is completed and inspected and qualified. The steps for lining crack repair are as follows:

[0008] B01: Inspection and marking of cracks, verify the number, length and width of cracks on site and mark them on the secondary lining structure;

[0009] B02: Clean the seams and treat the crack surface. Use a putty knife to scrape the evenly prepared crack repair glue to the cracks, and apply pressure and scrape repeatedly. The scraped glue is even and flat, with strong bonding force, and is ready to solidify;

[0010] B03: Paste the grouting nozzle and seal the crack surface. The rust on the chassis of the grouting nozzle must be removed and cleaned with acetone. Then apply the special glue evenly around the chassis. Each crack must have at least one grouting hole and one exhaust hole.

[0011] B04: Air compression test: after the sealing tape is hardened, an air compression test is required to check whether the sealing tape is sealed tightly;

[0012] B05: Grouting material for pouring concrete crack repair. For cracks with a width of B≤0.2mm, crack sealant is used for treatment, and the surface color difference treatment is performed after the surface is sealed. For cracks with a width of 0.2mm<B<0.5mm, crack sealant is used to seal the crack surface and crack repair glue is injected. After completion, the surface color difference treatment is performed. For cracks with a width of B≥0.5mm, grouting is performed after slotting and filling, and the surface color difference treatment is performed after completion.

[0013] B06: After grouting is completed and the slurry is polymerized and solidified, remove the grouting nozzle and apply concrete crack repair glue to seal it.

[0014] Furthermore, in step B02, for cracks with a width B ≥ 0.5 mm, a grinder or other equipment is used to first cut grooves along the direction of the cracks, with the groove depth and width both being 10 mm; depending on the position of the grooves, a steel brush is first used to remove debris from the cracks, including dust, lime and inferior concrete, and then both sides of the cracks are wiped with an organic solution such as alcohol to clean the cracks and keep them dry.

[0015] Furthermore, in step B03, the thickness is 1-2 mm, and it is pasted on the crack in alignment with the hole, and the spacing between the grouting nozzles is 3.5 to 4.0 cm depending on the length of the crack and the width of the crack.

[0016] Furthermore, in step B04, compressed gas passes through the grouting nozzle, and the air pressure is controlled at 0.2-0.4MPa. At this time, soapy water is applied on the sealing belt and around the grouting nozzle. If bubbles are found on the sealing belt after ventilation, it indicates a leaking part, which can be sealed again. The air test can be carried out from bottom to top for vertical seams and from the low end to the high end for horizontal seams.

[0017] Furthermore, in step B05, the cracks are grouted by air pump pressure injection method, and the grouting tank and the grouting nozzle are connected with a polyvinyl chloride high-pressure transparent tube. The connection must be tight and no air leakage is allowed. During the grouting process, attention should be paid to controlling the pressure. If the crack width is large, if the grouting is unobstructed, the pressure is controlled at 0.2MPa. If the grouting is not smooth, the pump pressure can be controlled at 0.4MPa. The order of grouting is as follows: for horizontal cracks, gradually press from the low end to the high end; for vertical arch cracks, gradually press from the bottom to the top; after grouting from one end, the grouting nozzle at the other end ejects the slurry after the gas in the crack is discharged when the concentration of the slurry is the same as that of the slurry injected. , grouting can be stopped and the grouting nozzle can be sealed while maintaining pressure; if no grouting is seen on the other side after grouting on one side of the through joint, grouting can be carried out once on the other side; for the unpenetrating arch joints, grouting from the adjacent nozzles must be seen; for the cracks that have been grouted, the grouting nozzles will be folded off one by one after the slurry solidifies, and the places where the grouting nozzles are pasted will be smoothed with special resin glue, and finally a layer of polymer cement slurry will be applied to the surface of each crack to ensure that it is tightly sealed and its color is kept as consistent as possible with the original concrete structure surface; after the grouting work is completed, the residual liquid in the grouting tank and grouting pipe will be blown clean with compressed air, and the pipeline and tools will be flushed with acetone for next use.

[0018] Furthermore, stage B also includes step B07, after the crack treatment is completed, surface color difference adjustment is performed on the cracks, glue injection holes and other locations with color difference on the lining surface.

[0019] Furthermore, the steps of grouting reinforcement of the tunnel bottom in Phase A are as follows:

[0020] A11: Position the primary supporting steel arch frame and secondary lining steel bars of the inverted arch;

[0021] A12: Positioning of grouting holes, avoiding the primary supporting steel arch frame of the invert and the secondary lining steel bars, and positioning the grouting holes at the bottom of the tunnel;

[0022] A13: Grouting hole position marking, the tunnel is divided into several grouting sections from outside to inside in the longitudinal direction, each grouting section is divided into four 2*2 matrix blocks, the four blocks are marked in sequence along the U-shaped path from the opening to the outside of the tunnel, and the grouting holes in each block are marked in sequence along the path from the outer circumference to the center;

[0023] A14: Drilling, placing steel pipes and grouting construction. Drill holes according to the grouting hole position marks, put in steel pipes after cleaning the holes, and then grouting. The construction sequence is: construct the grouting sections from the outside to the inside along the longitudinal direction of the tunnel, and grouting is carried out in four blocks in each grouting section. In each block, the construction is carried out according to the size of the numbers, first grouting the odd-numbered holes and then the even-numbered holes, and the construction is divided into two rounds of skipping holes. To prevent grouting, the next hole can be drilled only after the grouting of the previous hole in each block is completed.

[0024] Furthermore, in step A14, the drilling holes at the arch foot are inclined toward the outside of the tunnel.

[0025] Furthermore, in step A14, the steel flower tube is made of Q235 seamless steel tube, a hole of φ120 is drilled at the arch foot, and a steel flower tube of φ108×5mm is used, and a hole of φ120 is drilled in the middle part, and a steel flower tube of φ50×4mm is used.

[0026] Furthermore, it also includes a stage C. After the completion of stage B, the cracks are monitored in stage C, including: invert surface monitoring and crack monitoring.

[0027] Due to the adoption of the above technical solution, the present invention has the following beneficial effects:

[0028] 1. The present invention repairs lining cracks after reinforcing the bottom of the tunnel; first reinforcing the bottom of the tunnel to prevent settlement can prevent the tunnel from settling again in the later period and causing secondary rupture of the lining cracks; in addition, cracks with a width of B≤0.2mm are treated with crack sealing glue, cracks with a width of 0.2mm<B<0.5mm are treated with crack sealing glue to seal the crack surface and then inject crack repair glue, and cracks with a width of B≥0.5mm are treated with grouting after slotting and filling. Different crack sizes are treated accordingly to improve the crack repair effect and life; the technical problem that the traditional tunnel repair technology only repairs lining cracks, does not find the tunnel bottom for reinforcement to prevent settlement, does not have a specific treatment method according to the size of the cracks, and has a high probability of cracks occurring again is solved.

[0029] 2. The present invention uses segmentation, blocks and U-shaped paths to mark holes and grouting in sequence, which can facilitate construction and prevent damage to the local structure of the tunnel bottom caused by excessive drilling of multiple holes in the same local area; the next hole can be drilled only after the grouting of the previous hole in each block is completed, which can prevent grouting and improve reliability. The diameter of the steel flower pipe at the arch foot is larger, which can improve the structural strength of the steel flower pipe and improve the structural strength of the steel flower pipe after grouting.

[0030] 3. The present invention also provides a monitoring stage C, which can monitor the cracks after the crack repair is completed, so that the staff can understand the status of the tunnel, respond quickly and take positive measures when cracks occur, and reduce losses and maintenance costs. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] Figure 1 It is a process flow chart of the present invention.

[0032] Figure 2 It is a schematic diagram of the section block setting and grouting hole position marking of the present invention.

[0033] Figure 3 It is a schematic diagram of the construction of drilling holes, placing steel flower pipes and grouting in a cross section of a tunnel according to the present invention.

[0034] Figure 4 This is a schematic diagram of single crack repair according to the present invention;

[0035] Figure 5 is a schematic diagram of cross crack repairing of the present invention;

[0036] Figure 6 It is a schematic diagram of the distribution of 20 detection points in the tunnel of the present invention;

[0037] Figure 7 It is a schematic diagram of the steel flower tube of the present invention.

[0038] In the attached drawings, 1-steel flower tube, 2-slurry outlet hole, 3-slurry ring rib, 4-cone head. DETAILED DESCRIPTION

[0039] The specific implementation of the invention is further described below with reference to the accompanying drawings.

[0040] In the description of the present invention, it is necessary to understand that the terms "center", "length", "width", "up", "down", "vertical", "horizontal", "top", "bottom", "inside" and the like indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present invention.

[0041] In the present invention, unless otherwise clearly specified and limited, the terms "installed", "connected", "connected", "fixed" and the like should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be directly connected or indirectly connected through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0042] In the present invention, unless otherwise clearly specified and limited, a first feature being "above" or "below" a second feature may include that the first and second features are in direct contact, or may include that the first and second features are not in direct contact but are in contact through another feature between them. Moreover, a first feature being "above", "above" and "above" a second feature includes that the first feature is directly above and obliquely above the second feature, or simply indicates that the first feature is higher in level than the second feature. A first feature being "below", "below" and "below" a second feature includes that the first feature is directly below and obliquely below the second feature, or simply indicates that the first feature is lower in level than the second feature.

[0043] See also Figures 1 to 6 , a method for tunnel bottom grouting reinforcement and lining crack repair, comprising the following stages A, B and C;

[0044] Phase A: Grouting reinforcement at the tunnel bottom to prevent tunnel bottom settlement;

[0045] A11: Position the primary supporting steel arch frame and secondary lining steel bars of the inverted arch;

[0046] A12: Positioning of grouting holes, avoiding the primary supporting steel arch frame of the invert and the secondary lining steel bars, and positioning the grouting holes at the bottom of the tunnel;

[0047] A13: Grouting hole position marking, the tunnel is divided into several grouting sections from outside to inside in the longitudinal direction, each grouting section is divided into four 2*2 matrix blocks, the four blocks are marked in sequence along the U-shaped path from the opening to the outside of the tunnel, and the grouting holes in each block are marked in sequence along the path from the outer circumference to the center;

[0048] A14: Drilling, placing steel pipes and grouting construction, drilling according to the grouting hole position mark, placing steel pipes after cleaning, and then grouting; the construction sequence is: construct the grouting section from the outside to the inside along the longitudinal direction of the tunnel, and grouting the four blocks in each grouting section in turn. In each block, the construction is carried out according to the size of the numbers, first grouting the odd-numbered holes and then the even-numbered holes, and the construction is divided into two rounds of skipping holes; to prevent grouting, the next hole can be drilled only after the grouting of the previous hole in each block is completed. Specifically, the drilling holes at the arch foot are inclined to the outside of the tunnel; the steel pipe is made of Q235 seamless steel pipe, the drilling hole at the arch foot is φ120, and the steel pipe of φ108×5mm is used. The drilling hole in the middle part is φ120, and the steel pipe of φ50×4mm is used. The grouting material is cement paste, using 42.5 grade ordinary Portland cement, water-cement ratio: W:C=0.7:1~1:1, adjusted according to the on-site grouting situation. Grouting pressure: initial grouting pressure is 1.5~2Mpa, maximum grouting pressure (final pressure) is 4~5Mpa; grouting pressure is a provisional pressure and must be adjusted according to typical hole grouting test; the grouting process must focus on the existing lining structure, and the existing lining structure must not be damaged due to excessive pressure. Grouting pressure is measured in the steel tube. In order to control the initial setting time of the slurry, dry powder quick-setting agent can be added to the slurry, the amount of which is 6~10%, and it can be adjusted appropriately according to the on-site test conditions.

[0049] In this embodiment, before large-scale grouting, a typical hole position is selected for trial grouting. Grouting must be carried out in batches, and the interval between grouting shall not exceed the initial setting time of the slurry. Grouting can be terminated when one of the following conditions is met in a single grouting: (1) the grouting pressure gradually increases, and when the designed final pressure (5MPa) is reached, grouting is continued for more than 10 minutes; (2) the actual grouting volume of a single hole (unit: L) is close to Q = 900 × (L-2), where L is the length of the grouting pipe, and the grouting volume at the end is less than 30L / min.

[0050] Phase B: Lining crack repair, which is carried out after the tunnel bottom grouting reinforcement in Phase A is completed and inspected and qualified. The steps for lining crack repair are as follows:

[0051] B01: Inspection and marking of cracks, verify the number, length and width of cracks on site and mark them on the secondary lining structure;

[0052] B02: Clean the seams and treat the crack surface. Use a putty knife to scrape the evenly prepared crack repair glue onto the cracks, and apply pressure and scrape repeatedly. The scraped glue will be even and flat, with strong adhesion, and wait for solidification. For cracks with a width of B ≥ 0.5 mm, use a grinder or other equipment to cut grooves along the direction of the cracks, with a groove depth and width of 10 mm. According to the location of the grooves, first use a steel brush to remove debris from the cracks, including dust, lime and inferior concrete. After brushing, wipe both sides of the cracks with alcohol or other organic solvents. Clean the cracks and keep them dry.

[0053] B03: Paste the grouting nozzle and seal the crack surface. The rust on the chassis of the grouting nozzle must be removed and cleaned with acetone. Then apply the special glue evenly around the chassis with a thickness of 1-2 mm. Align with the holes and paste on the crack. The spacing between the grouting nozzles is 3.5-4.0 cm according to the length of the crack and the width of the crack. Each crack must have at least one grouting hole and one exhaust hole.

[0054] B04: Air compression test. After the sealing tape has hardened, an air compression test is required to check whether the sealing tape is tightly sealed. Compressed gas passes through the grouting nozzle, and the air pressure is controlled at 0.2-0.4MPa. At this time, apply soapy water on the sealing tape and around the grouting nozzle. If bubbles are found on the sealing tape after ventilation, it indicates a leak. The leak can be sealed again. The air test can be carried out from bottom to top for vertical joints and from the low end to the high end for horizontal joints.

[0055] B05: Grouting concrete crack repair grouting material, cracks with width B≤0.2mm, use crack sealant to treat, and adjust the surface color after sealing; cracks with width 0.2mm<B<0.5mm, use sealant to seal the crack surface and then inject crack repair glue, and adjust the surface color after completion; cracks with width B≥0.5mm, groove filling and then grouting, and adjust the surface color after completion; cracks are poured with air pump pressure injection method, and the grouting tank and grouting nozzle are connected with polyvinyl chloride high-pressure transparent tube. The connection must be tight and no air leakage; pay attention to control the pressure during the grouting process. For cracks with larger width, if the slurry flow is unobstructed, the pressure is controlled at 0.2MPa. If the crack slurry flow is not smooth, the pump pressure can be controlled at 0.4MPa; the order of grouting: for horizontal cracks, Gradually press from the low end to the high end; for vertical arch cracks, gradually press from bottom to top; after starting grouting from one end, when the grouting nozzle at the other end sprays out slurry with the same concentration as the pressed slurry after discharging the gas in the crack, grouting can be stopped and the grouting nozzle can be sealed while maintaining pressure; if no slurry is seen on the other side after grouting on one side of the through joint, press grouting can be done once on the other side; for unthrough arch joints, grouting from adjacent nozzles must be seen; for cracks that have been grouted, after the slurry solidifies, the grouting nozzles will be folded off one by one, and the places where the grouting nozzles are pasted will be smoothed with special resin glue, and finally a layer of polymer cement slurry will be applied to the surface of each crack to ensure tight sealing and keep its color as consistent as possible with the original concrete structure surface; after the grouting work is completed, use compressed air to blow out the residual liquid in the grouting tank and grouting pipe, and flush the pipeline and tools with acetone for next use.

[0056] B06: After grouting is completed and the slurry is polymerized and solidified, remove the grouting nozzle and apply concrete crack repair glue to seal it.

[0057] Phase C: After Phase B is completed, cracks are monitored in Phase C, including: invert surface monitoring and crack monitoring. Specifically, an optical level is used to monitor the settlement and uplift of the tunnel invert surface. An observation section is set every 10m, and the project department conducts measurements once a week. Crack monitoring sensors are used to monitor the width of tunnel cracks. The monitoring points are arranged at the side walls, with a total of 20 monitoring points.

[0058] In this embodiment, during the crack grouting construction, the grouting equipment consists of an electric air compressor, an air storage tank, an air delivery pipe, a slurry storage tank, a slurry delivery pipe and a grouting nozzle; the grouting nozzle is made of steel, has the functions of opening, closing and sealing, and is easy to bond to meet the process requirements of pressure testing, test injection, test exhaust and pressure maintenance after sealing; the slurry delivery and air delivery pipes are φ8mm, and the pressure-resistant pipes with a pressure resistance of more than 1MPa. The layout principle of the grouting nozzle: one nozzle is arranged every 25 to 30 cm for a single seam. Before pasting the grouting nozzle and sealing the seam, the concrete surface is treated along the seam to remove loose ash, sand and grease, so that the grouting nozzle and the sealing glue are attached to the solid and flat concrete base. For structural cracks with a large depth, the seam must be cut or drilled obliquely from bottom to top to the depth of the crack, and it must intersect with the fracture surface, and then the grouting pipe is buried in the hole. The grouting nozzle is set at the end, intersection and wider part of the crack, and a grouting pipe is added every 1 to 2m for the penetrating crack. The location of the glue injection base; (1) Set the glue injection base at the end of the crack, the intersection of the crack and the widest part of the crack; (2) Make a groove through the crack and the glue injection base must be set at both ends; (3) Each crack must have at least one grouting hole and an exhaust hole. The difference between the grouting of cross cracks and single cracks is that the location of the glue injection base and the grouting sequence are different, and the other process requirements are the same as the grouting of single cracks. When sealing the cracks, use a special sealing glue, the bonding strength between the glue and concrete is greater than 2.5MPa; the glue layer is uniform without bubbles and sand holes, the thickness is greater than 2mm, and it is connected to the grouting nozzle tightly. When the grouting pressure is high, glass fiber cloth can be added to enhance the bonding strength of the sealing tape glue, and the width of the fiber cloth is 6 to 8cm. After the sealing glue is cured, use clean and oil-free compressed air to test the pressure to confirm whether the grouting channel is unobstructed, sealed, and leak-free. During the construction process, the grouting sequence is from wide to thin and from bottom to top for vertical cracks. When drilling holes for grouting: drill holes on the crack surface to serve as grouting guide holes. Arch and top cracks: Drill holes along the cracks, with a depth of 5 cm, a diameter of 8 mm, and a hole spacing of 35 cm. All crack intersections should be drilled at the intersection. Hole cleaning and crack surface treatment: All holes must be cleaned with high-pressure air to prevent ash slag from blocking them. Then, along the cracks from top to bottom, the dust and slurry within 3 cm to 4 cm on both sides should be cleaned with a small hammer, a hand shovel, a steel brush, sandpaper, and a brush. The surface of the component should be leveled, the protruding parts should be chiseled off, and then scrubbed with acetone to remove the oil around the cracks. Be careful not to block the cracks during cleaning. In order to completely fill the concrete gaps with slurry and maintain pressure while ensuring that the slurry does not leak out in large quantities, the treated crack surface (except the holes and mouths) must be evenly brushed with polymer cement slurry from top to bottom twice along the crack direction to seal it (width 6-8 cm), and a layer of glass fiber (width 5-7 cm) should be tightly attached on it in sections to form a closed belt.

[0059] In this embodiment, see Figure 7The steel flower pipe 1 is made of seamless steel pipes of φ108×5mm and φ50×4mm, and the diameter of the grouting hole 2 is 10mm. The φ108 steel flower pipe 1 is provided with 3 10mm grouting holes 2 every 20cm, and no holes are punched within 2m from the end of the hole, and φ6 grouting ring reinforcement 3 is installed. The φ50 steel flower pipe 1 is provided with 3 10mm grouting holes 2 every 15cm, and no holes are punched within 2m from the end of the hole, and φ8 grouting ring reinforcement 3 is installed. The bottom of the steel flower pipe 1 is made into a cone head 4, and the joint of the cone head 4 should be tight and no grout leakage should be allowed.

[0060] The above description is a detailed description of the preferred feasible embodiments of the present invention, but the embodiments are not intended to limit the scope of the patent application of the present invention. All equivalent changes or modified changes completed under the technical spirit suggested by the present invention should fall within the patent scope covered by the present invention.

Claims

1. A method for tunnel bottom grouting reinforcement and lining crack repair, characterized in that: It includes the following phases A and B; Phase A: Grouting reinforcement at the tunnel bottom to prevent tunnel bottom settlement; Phase B: Lining crack repair, which is carried out after the tunnel bottom grouting reinforcement in Phase A is completed and inspected and qualified. The steps for lining crack repair are as follows: B01: Inspection and marking of cracks, verify the number, length and width of cracks on site and mark them on the secondary lining structure; B02: Clean the seams and treat the crack surface. Use a putty knife to scrape the evenly prepared crack repair glue to the cracks, and apply pressure and scrape repeatedly. The scraped glue is even and flat, with strong bonding force, and is ready to solidify; B03: Paste the grouting nozzle and seal the crack surface. The rust on the chassis of the grouting nozzle must be removed and cleaned with acetone. Then apply the special glue evenly around the chassis. Each crack must have at least one grouting hole and one exhaust hole. B04: Air compression test: after the sealing tape is hardened, an air compression test is required to check whether the sealing tape is sealed tightly; B05: Grouting material for pouring concrete crack repair. For cracks with a width of B≤0.2mm, crack sealant is used for treatment, and the surface color difference treatment is performed after the surface is sealed. For cracks with a width of 0.2mm<B<0.5mm, crack sealant is used to seal the crack surface and crack repair glue is injected. After completion, the surface color difference treatment is performed. For cracks with a width of B≥0.5mm, grouting is performed after slotting and filling, and the surface color difference treatment is performed after completion. B06: After grouting is completed and the slurry is polymerized and solidified, remove the grouting nozzle and apply concrete crack repair glue to seal it.

2. A method for tunnel bottom grouting reinforcement and lining crack repair according to claim 1, characterized in that: In step B02, for cracks with a width of B ≥ 0.5 mm, a grinder is used to cut grooves along the direction of the cracks, with the groove depth and width both being 10 mm; according to the position of the grooves, a steel brush is first used to remove debris from the cracks, including dust, lime and inferior concrete, and then both sides of the cracks are wiped with an organic solution to clean the cracks and keep them dry.

3. A method for tunnel bottom grouting reinforcement and lining crack repair according to claim 2, characterized in that: In step B03, the thickness is 1-2 mm, and it is aligned with the holes and pasted on the cracks. The spacing between the grouting nozzles is 3.5 to 4.0 cm depending on the length of the cracks and the width of the cracks.

4. The method for tunnel bottom grouting reinforcement and lining crack repair according to claim 1 is characterized by: In step B04, compressed gas passes through the grouting nozzle, and the air pressure is controlled at 0.2-0.4MPa. At this time, soapy water is applied on the sealing belt and around the grouting nozzle. If bubbles are found on the sealing belt after ventilation, it indicates a leaking part, which can be sealed again. The air test can be carried out from bottom to top for vertical seams and from the low end to the high end for horizontal seams.

5. The method for tunnel bottom grouting reinforcement and lining crack repair according to claim 1, characterized in that: In step B05, the cracks are grouted by air pump pressure injection method. The grouting tank and the grouting nozzle are connected with a polyvinyl chloride high-pressure transparent tube. The connection must be tight and leak-free. Pay attention to controlling the pressure during the grouting process. If the crack width is large, if the grouting is unobstructed, the pressure is controlled at 0.2MPa. If the grouting is not smooth, the pump pressure can be controlled at 0.4MPa. The order of grouting: for horizontal cracks, gradually press from the low end to the high end; for vertical arch cracks, gradually press from bottom to top; after grouting from one end, the grouting nozzle at the other end can discharge the gas in the crack and spray out slurry with the same concentration as the slurry injected. Stop grouting and seal the grouting nozzle while maintaining the pressure; if no grouting is seen on the other side after grouting on one side of the through joint, grouting can be performed on the other side once; for the unpenetrating arch joints, grouting must be seen from the adjacent nozzles; for the cracks that have been grouted, after the slurry solidifies, the grouting nozzles will be folded off one by one, and the places where the grouting nozzles are attached will be smoothed with special resin glue, and finally a layer of polymer cement slurry will be applied to the surface of each crack to ensure that it is tightly sealed and its color is kept as consistent as possible with the original concrete structure surface; after the grouting work is completed, use compressed air to blow out the residual liquid in the grouting tank and grouting pipe, and flush the pipeline and tools with acetone for next use.

6. The method for tunnel bottom grouting reinforcement and lining crack repair according to claim 1, characterized in that: Phase B also includes step B07, after the crack treatment is completed, the cracks, injection holes and other lining surface locations with color difference are subjected to surface color difference treatment.

7. The method for tunnel bottom grouting reinforcement and lining crack repair according to claim 1, characterized in that: The steps for grouting reinforcement of the tunnel bottom in Phase A are as follows: A11: Position the primary supporting steel arch frame and secondary lining steel bars of the inverted arch; A12: Positioning of grouting holes, avoiding the primary supporting steel arch frame of the invert and the secondary lining steel bars, and positioning the grouting holes at the bottom of the tunnel; A13: Grouting hole position marking, the tunnel is divided into several grouting sections from outside to inside in the longitudinal direction, each grouting section is divided into four 2*2 matrix blocks, the four blocks are marked in sequence along the U-shaped path from the opening to the outside of the tunnel, and the grouting holes in each block are marked in sequence along the path from the outer circumference to the center; A14: Drilling, placing steel pipes and grouting construction. Drill holes according to the grouting hole position marks, put in steel pipes after cleaning the holes, and then grouting. The construction sequence is: construct the grouting sections from the outside to the inside along the longitudinal direction of the tunnel, and grouting is carried out in four blocks in each grouting section. In each block, the construction is carried out according to the size of the numbers, first grouting the odd-numbered holes and then the even-numbered holes, and the construction is divided into two rounds of skipping holes. To prevent grouting, the next hole can be drilled only after the grouting of the previous hole in each block is completed.

8. The method for tunnel bottom grouting reinforcement and lining crack repair according to claim 7, characterized in that: In step A14, the drilling holes at the arch foot are inclined toward the outside of the tunnel.

9. A method for tunnel bottom grouting reinforcement and lining crack repair according to claim 8, characterized in that: In step A14, the steel flower tube is made of Q235 seamless steel tube, a hole of φ120 is drilled at the arch foot, and a steel flower tube of φ108×5mm is used. A hole of φ120 is drilled in the middle part, and a steel flower tube of φ50×4mm is used.

10. The method for tunnel bottom grouting reinforcement and lining crack repair according to claim 1, characterized in that: It also includes Phase C. After Phase B is completed, cracks are monitored in Phase C, including: invert surface monitoring and crack monitoring.

Images