Concrete structure cavity seepage-flow water application stable anchor injection repair method

Abstract

This invention discloses a method for repairing seepage-prone concrete cavities using anchoring and stabilization. The method includes: 1) determining the repair area based on inspection and identifying leaks and water inflow points for drainage; 2) cleaning the cavity surface; 3) applying an interface agent and applying non-woven fabric to the cleaned surface; 4) creating anchoring holes (deep holes) and grouting holes (shallow holes) on the non-woven fabric surface; 5) grouting the anchoring holes first, followed by grouting the grouting holes; 6) performing composite grouting on the drainage holes; and finally, removing the grouting pipe openings and finishing the surface after curing. This invention utilizes anchoring to stabilize the surface of cracked and wet concrete in concrete cavities, effectively solving the problems of wet surface adhesion and grout penetration and bonding. It effectively controls the instability and falling of cracked concrete in cavities and stabilizes the surface cracked concrete during grouting, preventing collapse and ensuring safe train operation.

Description

Technical Field

[0001] This invention relates to a method for repairing cavities and voids in concrete structures, belonging to the field of subway concrete construction technology, and particularly to a method for repairing seepage-water-permeable cavities in concrete structures by applying stable anchors. Background Technology

[0002] In subway concrete tunnels constructed using the cut-and-cover method, over-excavation of the excavated soil and ineffective air removal or vibration leakage within the formwork during concrete pouring can lead to the formation of cavities of varying sizes in the concrete. These cavities are then affected by train vibrations and water seepage, causing the outer surface of the concrete layer to crack and fracture, creating voids. These cavities and voids are susceptible to leakage and water flow due to external water pressure. The presence of cracks in these cavities poses a constant risk of further spalling, jeopardizing the safe operation of subway trains.

[0003] Conventional repair methods for cavities and voids in concrete structures.

[0004] 1. Repair method: Remove the broken concrete from the surface of the cavity and re-pour concrete.

[0005] ① Set up a construction operation platform; ② Remove the concrete from the cavity surface; ③ Drain leaking and flowing water; ④ Set up formwork; ⑤ Re-pour concrete; ⑥ After setting, grout and seal the drainage holes; ⑦ After setting, remove the formwork; ⑧ Resume train operation.

[0006] Problems exist:

[0007] 1. Excessive amounts of residual mud and debris in the concrete require additional backfilling and repair work, resulting in a large workload for cleaning and re-pouring concrete.

[0008] 2. The construction operation platform and formwork erection will occupy the tracks and prevent subway trains from passing.

[0009] 3. Due to the long construction period, the train suspension will have a certain impact on social traffic.

[0010] 2. Backfilling and grouting method is used to repair the cavity.

[0011] ① Erect formwork for the cavity; ② Drain and drain leaking water; ③ Fill the cavity with cement or other materials and grout; ④ Seal the drainage holes with grout; ⑤ Remove the formwork after it has set.

[0012] Problems exist:

[0013] Because the surface concrete of the cavity has poor self-stability due to cracking, direct backfilling and grouting can easily cause large-scale spalling of the cracked surface, necessitating the installation of scaffolding and formwork. The scaffolding and formwork obstruct the tracks, preventing trains from passing. The construction period and the time required for the cement grout to set also cause train stoppages, impacting public transportation.

[0014] III. Repair method using external steel plates

[0015] ① Drainage and drainage of water in the cavity; ② Cleaning of the concrete base surface in the cavity; ③ Attaching steel plates to the outside; ④ After curing, filling the cavity with cement grout through the pre-reserved grouting holes in the steel plates (drainage holes); ⑤ Removing the grouting holes after curing.

[0016] Problems exist:

[0017] 1. If the cavity is located at the top arch of the tunnel and the overhead contact line is below, the steel plate is prone to generating high voltage static current, which will affect the safe operation of the train and be detrimental to the tunnel concrete.

[0018] 2. The train cannot operate normally during the steel plate bonding and installation and cavity filling grouting.

[0019] 3. Repairing with steel plates is expensive.

[0020] IV. Repair method using external aramid fabric

[0021] Water seepage, leakage, and runoff are common problems in the upper semi-circular cavities of tunnels. The fractured concrete in these cavities is prone to wet seepage, making it impossible for the adhesive used to bond the aramid fabric to the wet, fractured concrete surface. During train operation and grouting filling of the cavities, the aramid fabric can easily detach, affecting safe train operation. Summary of the Invention

[0022] To address the shortcomings and deficiencies of existing technologies, the purpose of this invention is to provide a method for repairing concrete structure cavities by applying a water-permeable stabilizing anchor. This method uses an anchor to stabilize the surface of the cavity, effectively solving the problems of wet surface adhesion and hydrophilic grout penetration and bonding. It also effectively controls the instability and falling of the fractured concrete in the cavity, ensuring the safe operation of trains.

[0023] The objective of this invention is achieved through the following technical solutions.

[0024] A method for repairing seepage-prone and water-flow-prone cavities in concrete structures using anchor grouting, comprising the following steps:

[0025] 1) Based on the test data, determine the area range for repairing concrete cavities, identify leaks and water flow points for drainage treatment, and carry out cavity repair treatment.

[0026] 2) Clean the cavity treatment surface;

[0027] 3) Apply an interface agent and lay non-woven fabric on the cleaned surface;

[0028] 4) Anchor holes (deep holes) and grouting holes (shallow holes) are laid on the surface of the nonwoven fabric;

[0029] 5) Grout the anchor holes first, then grout the grouting holes;

[0030] 6) Perform composite grouting treatment on the drainage holes; after setting, remove the grouting pipe openings and perform surface finishing.

[0031] In the above-mentioned method for repairing seepage and water leakage in concrete structure cavities by applying stabilizing anchors, step 1) involves firstly guiding and draining the leaking and flowing water to a ditch according to the leakage and water leakage situation in the cavities. The broken surfaces of the cavities are then repaired, and the cavities are reinforced with stabilizing anchors. For leaking holes, water-stopping reinforcement is performed. For larger water leakage areas, a single-slurry cement-water glass grouting material (patent number: 3973655) is first used to quickly fill and seal the water leakage.

[0032] In the above-mentioned method for repairing the cavity seepage and water flow of concrete structure by applying a stabilizing anchor, step 2) involves cleaning the base surface of the detected fractured cavity, locating the leaks and water flow points during the cleaning process, and diverting the leaks and water flow into the drainage ditch in the interval.

[0033] In the above-mentioned method for repairing the seepage and water flow of concrete structure cavities by applying stabilizing anchors, step 3) involves cleaning and applying epoxy interface agent to the concrete base surface of the cracked cavity where leakage and water flow have been cleared and drained; repeated application is used to allow the interface agent to be fully absorbed by the concrete and form an initial adhesive film layer, after which a pre-cut non-woven fabric is applied to the interface agent adhesive film layer, requiring it to be flat and free of air bubbles.

[0034] An epoxy interface agent is evenly applied to the non-woven fabric layer to form a coating layer.

[0035] First, cement grouting is performed on the anchoring holes with a water-cement ratio of 0.6 to 1:1 and an injection pressure of 0.1 to 0.2 MPa. Then, epoxy grouting material is injected with an injection pressure of 0.2 to 0.3 MPa to form an anchor bolt between the deep hole grouting and the grouting pipe, stabilize the cavity layer of the surface layer, and prevent the grouting from increasing weight and falling.

[0036] In the above-mentioned method for repairing seepage water in concrete structure cavities by applying anchoring and stabilizing, step 4) involves creating holes on the surface layer after curing. These holes are divided into anchoring holes and grouting filling holes.

[0037] The anchoring holes should be 8-10cm deep into the solid concrete at the bottom of the cavity; the spacing between the anchoring holes should be 40cm.

[0038] The grouting hole depth extends 3-5 cm below the bottom of the cavity; the grouting hole diameter is between the two anchoring holes.

[0039] In the above-mentioned concrete structure cavity seepage-flowing stabilization anchoring repair method, in step 5), cement grout is first injected into the anchoring hole with a water-cement ratio of 0.6 to 1:1 and a construction pressure of 0.1 to 0.2 MPa; then epoxy grouting material is injected with an application pressure of 0.2 to 0.3 MPa, so that the deep hole grouting and the grouting pipe form an anchoring bolt, stabilizing the cavity layer and the surface layer, and preventing the grout weight from increasing and falling.

[0040] The above-mentioned method for repairing seepage and water leakage in concrete structure cavities using anchoring and stabilization techniques is described above.

[0041] In step 5), epoxy grouting material is first injected into the grouting hole to enhance the bond between the cement grout and the structural concrete in the cavity. The injection pressure is 0.3-0.4 MPa, and multiple injections are required to improve the bond strength between the cement grout and the concrete around the cavity.

[0042] Before construction, when large-area cavity fracture surfaces show broken concrete chunks forming voids, the voids should first be repaired to form a sealed surface with the cavity surface. The steps of the void repair process are as follows:

[0043] Cleaning inside the cavity; inserting expansion bolts; applying interface agent; layering and pressing epoxy repair mortar; and pre-embedding grouting pipes; grouting the pre-embedded pipes; and surface finishing.

[0044] In the above-mentioned method for repairing the seepage-flowing concrete structure cavity by applying a stable anchor, step 6) involves grouting the drainage holes in the cavity with a cement slurry-epoxy material composite; and cleaning and finishing the grouting pipes on the cavity treatment surface.

[0045] The cavity repair process is as follows: cleaning the cavity, inserting expansion bolts, applying interface agent, layering and pressing epoxy repair mortar and pre-embedded grouting pipes, grouting the pre-embedded pipes, and surface finishing.

[0046] Compared with the prior art, the present invention has the following beneficial technical effects:

[0047] 1) It will not affect the normal operation of trains and will not have a negative impact on social traffic;

[0048] 2) Solve the problem of stable penetration and bonding of concrete on the surface of wet, fractured, and cavitary areas;

[0049] 3) It saves on the amount of concrete removed from cavities and reduces the amount of concrete backfilling;

[0050] 4) Applicable to the operational requirements 2 hours after subway trains stop running, and meets the requirements for train operation the next day;

[0051] 5) The cavity is repaired by applying anchors to stabilize the fractured concrete surface of the cavity and using chemical anchors to control the self-falling effect of the fractured concrete. At the same time, the composite grouting technology of epoxy material and cement grout is used to not only improve the bonding ability of the interface between the new and old objects, but also to improve the density and strength of the cement grout due to the high permeability of the epoxy material.

[0052] Concrete interface agent:

[0053] JC / T 907-2018 (Effective September 1, 2018)

[0054] People's Republic of China Building Materials Industry Standard

[0055] Table 1 Physical and Mechanical Performance Requirements

[0056]

[0057] Table 2 Time Deviation of Maintenance Cycle

[0058] Maintenance cycle Time Deviation 24h ±0.5h 7d ±3h 11d ±6h 28d ±12h

[0059] Epoxy resin grouting material for concrete cracks:

[0060] People's Republic of China Building Materials Industry Standard

[0061] JC / T1041~2007 (implemented on November 1, 2007)

[0062] Table 3. Grout Properties of Epoxy Resin Grouting Materials

[0063]

[0064] Table 4 Sampling Quantity for Individual Tests

[0065] Serial Number Experimental Project Sample quantity / m 1 Slurry density 1000 2 Initial viscosity 500 3 Operable time / 20℃ 500 4 compressive strength 1000 5 Tensile shear strength 500 6 tensile strength 2000 7 Bond strength 500 8 impermeability 2000

[0066] Technical Specifications for Epoxy Resin Mortar:

[0067] DL / T5193—2004 (Standard)

[0068] Table 4.1 Technical Specifications of 1-1EP 01441-310 Type Epoxy Resin

[0069] project Technical indicators Appearance No obvious mechanical impurities Color number ≤5 Viscosity (25℃) Pa·s 6～26 Epoxy equivalent g / Eq 184～210 Volatile matter (110℃, 3h)% ≤1.8 Attached Figure Description

[0070] Figure 1 The diagram shows a large-area cavity fracture surface covered with a stable cavity anchor injection hole. Detailed Implementation

[0071] The present invention will be further described in detail below through specific preferred embodiments and effect test examples. However, these embodiments are for illustrative purposes only and are not intended to limit the invention. Unless otherwise specified, the contents mentioned in the embodiments are all mass percentage contents.

[0072] During the construction of the cut-and-cover tunnel, air cannot escape from the formwork during concrete pouring, creating cavities. The outer surface of these cavities is covered with varying thicknesses of concrete mortar due to the formwork support. After the formwork is removed, the cavities are not immediately visible. However, under the influence of train vibrations and external water seepage, the thin surface concrete of these cavities cracks, leading to splintering, leaks, and water ingress, posing a safety hazard to the operating subway trains.

[0073] To ensure the normal and safe operation of trains and reduce the impact on social traffic, the stabilization treatment of sudden leaks, water flow, and fractured surfaces in cavities using the stabilizing anchoring repair technology is an effective and safe emergency treatment measure for sudden large-area concrete spalling, leaks, and water flow defects in subways. Its characteristics are: it can be carried out during the 2-3 hours of subway shutdown at night. After drainage, an epoxy interface agent is used to form a stabilizing coating layer on the damp fractured concrete surface.

[0074] This approach creates a safe construction environment for the next stage of cavity filling and repair, effectively solving the problem of handling large-area leakage and water flow in concrete cavities under the condition that subway trains are running continuously and safely. The key focus is on solving the technical problem of bonding and self-stabilizing leaking, water-flowing, and cracked concrete. Its technical benefits include social and economic advantages while maintaining train operation, and it saves on investment and treatment costs compared to conventional methods such as formwork backfilling, steel plate reinforcement, and aramid fabric treatment.

[0075] The present invention employs a method of applying stable, cracked, and wet concrete to the surface of a cavity, effectively solving the problems of wet surface adhesion and hydrophilic grout penetration and bonding of wet concrete. This method effectively controls the instability and falling of cracked concrete in the cavity, ensuring the safe operation of the train.

[0076] By combining the use of anchor injection to fill the cavity, chemical anchors formed through grouting holes, and cement-epoxy grouting material, a non-shrink, well-bonded solid body is formed, and the effect has remained stable for 18 years.

[0077] The repair of concrete cavities was carried out by applying stabilizing anchors. The entire construction process was conducted within 2-3 hours after the train stopped running, ensuring the normal and safe operation of the train and creating a positive social impact and economic benefit for social transportation.

[0078] Because it can be applied to seeping and damp surfaces, it reduces the need for concrete removal and re-pouring, saving on treatment costs and construction time. It is an effective emergency treatment measure and repair technology for quickly and efficiently stabilizing fractured surfaces and ensuring normal train passage.

[0079] This invention provides an emergency repair method for large-area cavity fracture surface leakage, water flow and block falling defects in operating subway tunnels. On the one hand, it prevents the falling of fractured concrete blocks from the tunnel cavity surface and water flow from affecting the safety of train operation. On the other hand, it performs cavity anchoring repair after applying a stable cavity fracture surface.

[0080] Repair technology for large-area cavities and cracked, wet concrete in tunnels under continuous rail transit operation - application of stabilizing anchor filling repair method.

[0081] 1. Clean the base surface of the detected fractured cavity, locate the leaks and water flow points during the cleaning, and guide the leaks and water flow into the interval ditch.

[0082] 2. Clean and apply epoxy interface agent to the broken and hollow concrete base surface that has been cleaned and drained of leaks and water. Repeat the application to allow the interface agent to be fully absorbed by the concrete and form an initial adhesive film layer. Then, apply the pre-cut non-woven fabric to the interface agent adhesive film layer, ensuring it is flat and free of air bubbles. Apply epoxy interface agent evenly to the non-woven fabric layer to form the adhesive top layer.

[0083] 3. After setting, create holes in the surface layer. These holes are divided into anchor holes and grouting holes. Anchor holes should be 8-10cm deep into the solid concrete at the bottom of the cavity, and grouting holes should be 3-5cm deep into the cavity. The anchor holes should be spaced 40cm apart, and the grouting hole diameter should be between the two anchor holes. See [reference needed]. Figure 1 Early-strength cement is used for external sealing of buried pipes.

[0084] 4. First, apply cement grout to the anchoring holes with a water-cement ratio of 0.6 to 1:1 and a construction pressure of 0.1 to 0.2 MPa. Then, apply epoxy grout with a grouting pressure of 0.2 to 0.3 MPa. This will allow the deep hole grouting to form an anchoring bolt with the grouting pipe, stabilize the cavity layer and the surface layer, and prevent the grouting weight from increasing and causing it to fall.

[0085] 5. Apply epoxy grout to the grouting holes to enhance the bond between the cement grout at the bottom of the cavity and the structural concrete. The grouting pressure is 0.3-0.4 MPa. Multiple grouting sessions are required to ensure the penetration, consolidation and reinforcement effect on the inner surface of the fractured concrete.

[0086] 6. Before construction, if large areas of cavities are cracked and broken concrete blocks fall off, forming voids, the voids should be repaired first to form a closed surface with the cavity.

[0087] 7. Perform cement grout-epoxy composite grouting on the drainage holes in the cavity.

[0088] 8. Clean and finish the grouting pipe on the cavity treatment surface.

[0089] Void repair:

[0090] ① Cleaning the cavity; ② Inserting expansion bolts; ③ Applying interface agent; ④ Layered filling with epoxy repair mortar and pre-embedded grouting pipes; ⑤ Grouting the pre-embedded pipes; ⑥ Surface finishing.

[0091] This invention relates to a stabilization technique for water seepage, leakage, and flow on large-area fractured concrete surfaces under the vibration load of running trains.

[0092] A composite grouting technology combining epoxy-based grouting materials and cement grouting is used to create composite anchors and filling repair techniques within concrete cavities.

[0093] Epoxy grouting materials improve and enhance the bonding ability of cement filling grout, reduce the self-shrinkage of cement grout, and improve the mechanical strength of cement filling grout.

[0094] The cavity with large-flow water is rapidly filled and sealed using a single-slurry cement-water glass material. (Patent No.: 3973655)

[0095] like Figure 1 As shown, the repair process of this invention using a stabilizing agent to repair cracked and wet concrete on the surface of a cavity is as follows:

[0096] Based on the test data, the area to be repaired for the cavity is determined; the leaking water level is located and drained; the cavity is repaired, and the cavity treatment surface is cleaned; an interface agent is applied to the cleaned surface and non-woven fabric is applied; anchor holes (deep holes) and grouting holes (shallow holes) are arranged on the non-woven fabric surface; the anchor holes are grouted first, followed by the grouting holes; the drainage holes are treated with composite grouting; after setting, the surface of the grouting pipe opening is cleaned and finished.

[0097] During the construction of the mined tunnel, air cannot escape from the formwork during concrete pouring, forming cavities. The outer surface of these cavities is covered with varying thicknesses of concrete mortar due to the formwork support. After the formwork is removed, the cavities cannot be immediately observed. Under the influence of train vibration and external water seepage, the thin surface concrete of the cavities develops cracks, leading to breakage, leakage, and water flow, posing a safety hazard to the operating subway trains.

[0098] To ensure the normal and safe operation of trains and reduce the impact on social traffic, the stabilization treatment of sudden leakage and water flow in cavitary fracture surfaces, using the stabilizing anchor repair technology, is an effective and safe emergency treatment measure for sudden large-area concrete spalling and leakage / water flow defects in operating subways. Its characteristics include...

[0099] This method can be carried out during the 2-3 hours of subway downtime at night. After drainage, an epoxy interface agent is applied to form a stable overlay on the damp, cracked concrete surface. This creates a safe construction environment for the subsequent cavity filling and repair, effectively solving the problem of large-area leakage and water flow in concrete cavities under the condition that the subway trains are running and safe to operate. The key focus is on solving the technical problem of self-stabilizing leaking and water-flowing cracked concrete. Its technical benefits include social and economic benefits under the condition that the trains are running, and it saves on investment and treatment costs compared to conventional methods such as formwork backfilling, steel plate reinforcement, and aramid fabric treatment.

[0100] Effect Test Example 1

[0101] During the operation of a subway train in a section of a subway tunnel, cracks and spalling of the surface concrete within a 30m radius of the secondary lining of the tunnel structure were caused by blasting from a nearby construction site. Upon inspection, the concrete showed signs of large-area cavities and spalling voids.

[0102] At the 12 o'clock position of tunnel K9+703, a piece of secondary lining concrete collapsed, with an area of ​​approximately 0.05㎡. Double-layered reinforcing steel bars were visible within the collapsed cavity. On-site probing revealed the cavity to be approximately 2.8m wide laterally and 2.3m long longitudinally. The cavity's internal height was 17-20m, and its area was approximately 5.88㎡. Due to blasting vibrations, the surface concrete of the cavity fractured, and blasting vibration cracks appeared within a surrounding area of ​​approximately 6㎡. Simultaneously, at the 12 o'clock position of tunnel K9+724, a cavity crack of approximately 1.0㎡ was observed.

[0103] Due to the large area of ​​the fractured cavity and its location above the overhead contact line in the tunnel, within the train track area, any subsequent breakage poses a constant threat to train safety. While formwork protection would be feasible due to the large area affected and prolonged train downtime, a new stabilizing anchoring technique using a layered infiltration method has been developed. This technique effectively stabilizes the fractured concrete in the cavity, controlling breakage and preventing further breakage. Combined with a low-pressure, slow-injection, repeated grouting process, this method effectively addresses the problem of repairing large-area cavities and voids in concrete under safe train operation conditions. Years of testing have shown stable results. Post-repair monitoring confirms that the repair meets the safety requirements for subway operation.

[0104] Effect Test Example 2

[0105] Eight years after its completion and commissioning, a subway tunnel developed cracks and spalling on the surface of the concrete secondary lining at points 1-11 on the tunnel's arch, due to external water seepage and train vibration. The spalling area was approximately 1.0 square meters, with the height difference of the cavities ranging from 5 to 15 centimeters. The surrounding concrete of the cavities was also detached, with individual cavities measuring approximately 4.0-5.0 square meters and extending longitudinally from 5.0 to 10.0 meters along the tunnel. Radar detection revealed four locations with an upward longitudinal cavity of 45 meters, the largest cavity having a longitudinal length of 10 meters and the largest void having a longitudinal length of 6.0 meters.

[0106] The reason is that the construction project involved under-excavation or over-excavation. When the concrete was poured, the air accumulated in time could not be discharged in time, forming an air cavity. Due to long-term water leakage, the surface concrete of the secondary lining structure was eroded and damaged, resulting in erosion disease and reduced strength. Under the vibration of train operation, when the vibration effect is greater than the tensile shear stress value of the concrete on the cavity surface, the surface concrete of the cavity will crack and fall off, forming a void, revealing a hidden cavity defect.

[0107] The repair technique of applying a stabilizing anchor and reinforcing treatment resulted in no water seepage on the surface of the treated cavities and voids, and the treatment effect was stable, meeting the requirements for safe operation of trains without interruption.

[0108] The specific process of the repair technique involving applying stabilizing anchors and reinforcement is as follows:

[0109] 1) Determine the repair area of ​​the cavity based on the test data, and find the leaks and water flow points for drainage treatment;

[0110] 2) Repair the cavities;

[0111] 3) Clean the cavity treatment surface;

[0112] 4) Apply an interface agent and lay non-woven fabric on the cleaned surface;

[0113] 5) Anchor holes (deep holes) and grouting holes (shallow holes) are laid on the surface of the non-woven fabric;

[0114] 6) Grout the anchor holes first, then grout the grouting holes;

[0115] 7) Perform composite grouting treatment on the drainage holes; remove and finish the surface of the grouting pipe opening after it has set.

[0116] The repair technique of applying stabilizing anchors and reinforcing the concrete in the cavities was used to stabilize the fractured and damaged concrete in a timely manner, ensuring the safe operation of trains. After repair, the concrete in the tunnel cavities showed no signs of dampness and remained stable after years of train operation. This approach also avoided large-scale cleaning, saving investment and time. Post-repair monitoring showed that the tunnel met the safety requirements for subway operation.

[0117] Effect Test Example 3

[0118] After a certain mined tunnel was opened to traffic, various types of water leakage and spalling issues appeared at the 2 o'clock to 10 o'clock positions on the upper semicircle of the tunnel. The leakage areas varied in size and were distributed in multiple locations. According to defect analysis, the main problem was formwork displacement during concrete pouring, resulting in a thin concrete protective layer around the reinforcing bars. The reinforcing bars and exposed waterproof membrane could be seen through the gaps caused by spalling, leading to water seepage and flow problems in the openings and surrounding concrete. Due to the inadequate compaction of the concrete during construction, external water seepage formed excellent channels for water flow.

[0119] First, drainage holes are laid out according to the water flow conditions in cavities and voids. Cavities with broken pieces are repaired, and then cavities are reinforced and repaired using a stabilizing anchoring technique. Finally, the drainage holes are filled with cement grout and epoxy grouting material to stop the water flow. For larger flows, a single-slurry cement-water glass grouting material (patent number: ZL201811382849.4) is used for filling and stopping the water flow.

[0120] The specific process of the repair technique involving applying stabilizing anchors and reinforcement is as follows:

[0121] 3) Determine the repair area of ​​the cavity based on the test data, and find the leaks and water flow points for drainage treatment;

[0122] 4) Repair the cavities;

[0123] 3) Clean the cavity treatment surface;

[0124] 4) Apply an interface agent and lay non-woven fabric on the cleaned surface;

[0125] 5) Anchor holes (deep holes) and grouting holes (shallow holes) are laid on the surface of the non-woven fabric;

[0126] 6) Grout the anchor holes first, then grout the grouting holes;

[0127] 7) Perform composite grouting treatment on the drainage holes; remove and finish the surface of the grouting pipe opening after it has set.

[0128] After treatment and repair, the large water flow channel in the cavity was effectively sealed off. The concrete cavities and voids were free of moisture, the concrete in the cavity areas was flat and stable, and the cavity areas were tightly bonded to the surrounding concrete, demonstrating a stable treatment effect. Post-repair monitoring showed that the system met the requirements for safe operation of the subway.

[0129] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention in any way. Therefore, any simple modifications, equivalent changes, and alterations made to the above embodiments based on the technical essence of the present invention without departing from the scope of the present invention shall still fall within the scope of the present invention.

Claims

1. A method for repairing seepage-water-permeable cavities in concrete structures using anchoring and stabilization techniques, characterized in that: The anchoring repair method includes the following steps: 1) Before construction, when large areas of cavity fracture surfaces show broken concrete chunks falling off and forming voids, the voids should be repaired first to form a closed surface with the cavity surface; Based on the detection, the scope of repair and treatment is determined and the situation is determined. The leak and water flow points are identified and drained. In step 1), the leak and water flow points are drained first according to the situation of the cavities and hollows. The leak and water flow points are drained to the water ditch. The cavities appearing on the broken surface of the cavity are repaired. Then, the cavity is covered and reinforced with anchoring. The steps for cavity repair are as follows: Cleaning the cavity; inserting expansion bolts; applying interface agent; layering and pressing epoxy repair mortar and pre-embedded grouting pipes; grouting the pre-embedded pipes; surface finishing; 2) Clean the cavity treatment surface; In step 2), clean the base surface of the detected fractured cavity, find the leak and water flow points during the cleaning, and guide the leak and water flow into the interval ditch. 3) Apply an interface agent and apply non-woven fabric to the cleaned surface; In step 3), clean the concrete base surface of the cracked cavity area that has been cleaned and drained of leaks and water, and apply epoxy interface agent; Repeat the application until the interface agent is fully absorbed by the concrete to form an initial adhesive film layer, then apply the pre-cut non-woven fabric on the interface agent adhesive film layer, ensuring it is flat and free of air bubbles; Apply epoxy interface agent evenly on the non-woven fabric layer to form a topcoat layer; 4) Make holes on the non-woven fabric surface; In step 4), after curing, make holes on the surface layer. The holes are divided into anchor holes and grouting holes; the spacing between anchor holes is 40cm; the depth of anchor holes extends to the bottom of the cavity and the solid concrete 8~10cm; the depth of grouting holes extends to the bottom of the cavity 3~5cm. First, cement grouting is performed on the anchoring holes with a water-cement ratio of 0.6~1:1 and an injection pressure of 0.1~0.2 MPa; then epoxy grouting material is injected with an injection pressure of 0.2~0.3 MPa, so that the grouting in the anchoring holes and the grouting pipe form an anchoring bolt, stabilizing the concrete surface layer in the fractured cavity and preventing it from falling due to added weight during the grouting process; 5) Grout the grouting holes with epoxy grouting material to enhance the bond between the cement grout at the bottom of the cavity and the structural concrete. The grouting pressure is 0.3~0.4 MPa. Multiple groutings are required to ensure the penetration, consolidation and reinforcement effect on the inner surface of the fractured concrete. 6) Perform composite grouting treatment on the drainage holes; after setting, remove the grouting pipe opening and perform surface finishing; in step 6), perform composite grouting of cement slurry and epoxy grouting material on the drainage holes in the cavity, perform water-stopping and water-flowing reinforcement treatment on the cavity, and perform grouting pipe finishing treatment on the cavity treatment surface.

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