Concrete construction joint post-setting composite waterstop reinforcing structure and construction method thereof

Abstract

The application discloses a concrete construction joint post-positioned composite waterstop reinforcing structure and a construction method thereof, which comprises a full-length groove opened on both sides of old concrete, a pair of waterstop steel plates, a composite PN water-swelling waterstop strip, a plurality of groups of connecting and locking assemblies containing upper connecting screw rods, lower connecting screw rods and adjusting nuts, a reserved grouting hole and a plastic rubber strip; the waterstop steel plate is provided with a vertical main plate and a horizontal wing plate, and the surface of the steel plate is provided with an epoxy anticorrosive primer layer and an epoxy interface sealing adhesive layer; the waterstop steel plate can be adjustably clamped and pressed through the connecting and locking assembly, a grouting cavity is formed in the full-length groove and provides a deformation allowance for the waterstop strip, the plastic rubber strip constructs a grouting anti-channeling leakage barrier, and a multiple progressive waterproof line composed of grouting filling plugging, composite PN water-swelling waterstop strip water blocking, epoxy interface sealing adhesive sealing and water physical isolation of the waterstop steel plate is formed; the construction quality and long-term waterproof durability of the post-positioned reinforcement of the existing construction joint of the underground structure can be effectively improved.

Description

Technical Field

[0001] This invention belongs to the field of waterproofing technology for underground engineering, and more specifically, relates to a post-construction composite waterproofing reinforcement structure for concrete construction joints and its construction method. Background Technology

[0002] Horizontal and vertical construction joints in underground reinforced concrete structures (such as underground utility tunnels, caissons, pipe jacking shafts, box culverts, and underground parking garages) are prone to leakage and are weak points. Conventional underground engineering waterproofing design requires the pre-embedding of embedded waterstop steel plates before concrete pouring. These plates extend the seepage path of groundwater, thus achieving waterproofing at the construction joints. However, on construction sites, factors such as lax process control, tight deadlines, design changes, and inadequate on-site briefings often result in the waterstop steel plates being omitted from the construction joints after the lower layer of concrete has been poured, or the pre-embedded waterstop steel plates becoming damaged and ineffective, creating permanent waterproofing defects. If effective reinforcement and waterproofing measures are not taken to address these defects, under long-term external groundwater pressure, the construction joints are highly susceptible to seepage and leakage, severely affecting the normal use and service durability of underground structures.

[0003] Currently, there are two main remedial solutions for construction joint defects caused by missing or damaged waterstop steel plates in the engineering field, but both have significant technical flaws: The first type of solution involves using only a single flexible material such as water-swellable sealing strips and sealant for caulking and sealing. This solution relies on a single waterproofing line to resist groundwater, which has limited water pressure resistance. Under the alternating wet and dry conditions underground and the long-term erosion of soil and water, the sealing strip is prone to aging and delamination from the concrete substrate. In high groundwater conditions, the probability of leakage recurrence is high, making it difficult to meet the waterproofing requirements for long-term service of underground structures with a Class I waterproofing level.

[0004] The second option involves extensively removing the existing concrete structure, creating new trenches, and then installing water-stop steel plates. This option requires extensive removal of the existing concrete structure, which can easily disturb or even sever the reinforcing steel bars of the main structure, reducing the structural safety margin. Furthermore, extensive removal generates a large amount of dust and solid waste, has a long construction period, high project costs, causes significant damage to the existing structure, and is subject to numerous limitations in on-site implementation.

[0005] In addition to the inherent defects of the two mainstream remedial solutions mentioned above, the existing remedial structural system also has several technical shortcomings: First, it lacks a grouting anti-leakage isolation structure. During subsequent pressure grouting, the grout can easily flow downwards along the gaps at the bottom of the structure, contaminating the existing concrete below. At the same time, it makes it difficult to establish grouting pressure and the gaps are not filled tightly. Second, the metal waterstop components lack a complete anti-corrosion system. The waterstop steel plate is prone to corrosion and expansion when exposed to groundwater and soil environment for a long time. The corrosion products will damage the steel plate-concrete bonding interface and further induce leakage. Third, it lacks an adjustable locking and positioning structure. The waterstop steel plate installed later is difficult to achieve a tight fit with the concrete base surface. A seepage gap remains between the steel plate and the concrete, resulting in a high risk of waterstop failure.

[0006] Existing technologies also disclose some construction joint water-stopping techniques: some use telescopic support components to clamp the formwork in both directions, mainly to solve the quality defects of bulging and grout leakage during the pre-embedded construction of water-stop steel plates. However, this type of solution is only suitable for the pre-embedded condition before concrete pouring and cannot be used for post-installation water-stopping reinforcement work on existing construction joints that have been poured and have missing or damaged water-stopping components. Others use U-shaped channels with multiple sets of water-stopping components to achieve water-stopping, but this requires prefabricated U-shaped channels and special formwork, resulting in a complex overall structure. It is difficult to implement on-site for vertical construction joints and is not suitable for post-installation reinforcement of existing structures. Still others use combined steel plate water-stopping combined with multiple waterproofing measures and drainage measures. This solution is mainly for the interface of newly built structures implemented in phases. It still cannot solve the problem of post-installation reinforcement after the water-stopping components of existing construction joints are missing or damaged. At the same time, it requires the installation of a large number of water-stopping components, resulting in high construction costs.

[0007] Therefore, there is an urgent need to develop a composite waterproofing and reinforcement structure for construction joints that minimizes damage to the original structure, has multiple waterproofing lines, incorporates grouting to prevent leakage, features an adjustable locking system, and provides excellent corrosion protection, along with its construction method. Summary of the Invention

[0008] To address the aforementioned deficiencies or improvement needs of existing technologies, this invention provides a post-construction composite waterstop reinforcement structure and its construction method for concrete construction joints. This involves creating a continuous groove on the surface of the old concrete side as a grouting cavity while allowing for deformation allowance of the waterstop strip. The structure includes paired waterstop steel plates with transverse flanges, a composite PN water-swellable waterstop strip, multiple sets of connecting and locking components consisting of connecting bolts and adjusting nuts, pre-drilled grouting holes, and a bottom plastic strip. The waterstop steel plates are coated with an epoxy anti-corrosion primer and an epoxy interface sealing adhesive layer. The connecting and locking components allow for adjustable clamping and pressing of the waterstop steel plates on both sides. Combined with subsequent pressure grouting, this constructs a system that includes grout filling. This invention employs a multi-layered waterproofing system, including sealing, water-swellable composite PN water-resistant strips, epoxy interface sealing adhesive, and physical waterproofing with a water-stop steel plate. The plastic strips form a barrier against grout leakage, and the transverse flanges of the water-stop steel plate extend into the post-cast concrete, extending the seepage path. This invention eliminates the need for large-scale removal of existing concrete, avoiding disturbance to the original reinforcing steel. The synergistic effect of multiple waterproofing lines reduces the probability of recurrence, ensuring a tight fit between the post-installed water-stop component and the concrete substrate. It establishes stable grouting pressure for thorough filling of gaps and includes comprehensive anti-corrosion treatment for metal components, significantly improving the construction quality and long-term waterproofing durability of post-installed water-stop reinforcement in underground structures.

[0009] To achieve the above objectives, the present invention provides a post-construction composite water-stop reinforcement structure for concrete construction joints. This structure is located at the construction joint between the old concrete and the post-construction concrete poured on top of the old concrete. It includes a continuous longitudinal groove along the construction joint on both sides of the old concrete; water-stop steel plates located at the junctions of the old concrete and the post-construction concrete on the left and right sides of the construction joint and covering the construction joint; composite PN water-swellable water-stop strips clamped between the water-stop steel plates and the old concrete along the longitudinal direction of the construction joint; multiple sets of connecting and locking components bridging the two water-stop steel plates; multiple reserved grouting holes on the water-stop steel plates communicating with the corresponding longitudinal groove cavities; and a plastic strip continuously fixed to the lower bottom surface of the water-stop steel plates. The water-stop steel plate includes a vertical main plate and a transverse wing plate perpendicularly disposed on the side of the vertical main plate; the lower part of the vertical main plate covers the continuous groove on the old concrete, and the upper extension of the vertical main plate extends into the post-poured concrete; the transverse wing plate extends vertically from the side of the vertical main plate toward the post-poured concrete and extends into the post-poured concrete to form an interlocking water-stop section; the water-facing surface and exposed surface of the water-stop steel plate are coated with epoxy anti-corrosion primer, and the bonding contact surface with the concrete is coated with epoxy interface sealant. The continuous groove forms a sealed grouting cavity and provides deformation allowance for the composite PN water-swellable waterstop strip under pressure and expansion upon contact with water. The plastic strip is used to press and seal the gap between the bottom of the waterstop steel plate and the old concrete, forming a barrier to prevent grout leakage. The connecting locking assembly is used to adjust the distance between the waterstop steel plates on both sides, so that the waterstop steel plate and the composite PN water-swellable waterstop strip are pressed tightly against the old concrete base. The structure allows for post-installed waterstop reinforcement of existing construction joints that have been formed, missing, or have damaged pre-embedded waterstop steel plates, without the need for large-scale removal of the old concrete structure.

[0010] Furthermore, the connecting locking assembly includes an upper connecting screw, a lower connecting screw, and adjusting nuts assembled at both ends of each connecting screw; the upper and lower connecting screws are bridging and passing between two water-stop steel plates, arranged in layers and staggered in a quincunx pattern along the height direction of the construction joint; the clamping distance between the two water-stop steel plates is adjusted by the adjusting nuts; after locking, the excess protruding sections of the upper and lower connecting screws are cut off, and anti-corrosion coatings are applied to the cut surfaces of the screws and the surfaces of the adjusting nuts.

[0011] Furthermore, the upper connecting screw and the lower connecting screw are made of round steel, and the two ends of the screw are machined with external thread sections of 10-20cm; the spacing between the screws on the same horizontal plane is 0.8m-1.2m; the anti-corrosion coating is a waterproof asphalt epoxy paint anti-corrosion layer.

[0012] Furthermore, the width of the through groove is 3-5cm; the depth of the through groove is 2-3cm; the through groove runs through the entire construction joint, the base of the groove is solid, and the groove wall forms a lateral limit on the water-stop steel plate.

[0013] Furthermore, the composite PN water-swellable sealing strip is a putty-type sealing material with a rubber matrix and water-absorbing components; its volume expansion rate is ≥150%. The composite PN water-swellable waterstop strip is pasted and fixed to the surface of the waterstop steel plate facing the construction joint; the composite PN water-swellable waterstop strip is set at a distance of 5-8cm from the construction joint in the old concrete. When the locking assembly is in the locked state, the composite PN water-swellable waterstop strip is clamped between the vertical main plate of the waterstop steel plate and the base surface of the old concrete around the continuous groove; when multiple waterstop strips are installed together, they are lapped, and the lap length of the waterstop strip is not less than 100mm; the lapped parts are coated with sealant.

[0014] Furthermore, after the connecting locking assembly is locked, the adjusting nut is configured such that the initial preload stress of the composite PN water-swellable sealing strip is 0.15MPa to 0.35MPa.

[0015] Furthermore, the waterstop steel plate is made of carbon structural steel; the splicing position of the waterstop steel plate along the length direction is fully welded, and the weld is provided with a rust removal and anti-corrosion layer; the vertical main plate and the horizontal wing plate of the waterstop steel plate together make the waterstop seepage path of the construction joint (3) extend by no less than 3 times compared with the straight construction joint.

[0016] Furthermore, the diameter of the reserved grouting holes is 3-5cm, and the spacing between adjacent reserved grouting holes along the construction joint is 35cm-50cm.

[0017] Furthermore, the plastic strip is a self-adhesive EVA foam sealing strip, and the overlap length of the plastic strip segments is not less than 5cm; after being pressed by the connecting locking component, the plastic strip undergoes elastic deformation, isolating and blocking the downward flow channel of the grout.

[0018] A second aspect of the present invention provides a construction method for a post-installed composite waterproofing reinforcement structure for concrete construction joints, comprising the following steps: S1: Carry out a roughening and cleaning operation along the entire construction joint where the old concrete meets the post-cast concrete, removing laitance, loose aggregate, oil stains and debris from the joint surface; along the direction of the construction joint, use manual labor and a small roughening machine to continuously chisel and form a continuous groove on both sides of the old concrete; remove dust and debris from the inside of the continuous groove and the interface of the construction joint, and allow the base surface to dry naturally. S2: Sandblasting is performed on the paired waterstop steel plates to remove rust; epoxy anti-corrosion primer is applied to the water-facing side and the exposed surface of the waterstop steel plates; epoxy interface sealant with a thickness of 0.8mm to 1.2mm is evenly applied to the bonding surface of the waterstop steel plates in contact with the concrete; multiple reserved grouting holes connected to the longitudinal groove are drilled through the waterstop steel plate body; plastic strips are pasted longitudinally on the bottom lower end face of the waterstop steel plates. S3: Adhere and fix the composite PN water-swellable waterstop strip to the surface of the waterstop steel plate facing the construction joint; the waterstop strip is continuously laid along the construction joint, and the waterstop strip is connected by overlapping at the joints, with an overlap length of not less than 100mm, and sealant is applied to the overlap section; after the waterstop strip is pasted, take protective measures to cover the waterstop strip. S4: Install the waterstop steel plate equipped with the composite PN water-swellable waterstop strip and plastic strip, ensuring that the lower part of the vertical main plate of the waterstop steel plate covers the long groove, and the plastic strip at the bottom of the waterstop steel plate is in close contact with the old concrete surface; install the upper and lower connecting screws of the connecting locking assembly between the two waterstop steel plates in layers, and install adjusting nuts at both ends of each connecting screw; tighten the adjusting nuts at both ends to adjust the clamping distance between the two waterstop steel plates, so that the waterstop steel plate presses firmly against the old concrete base surface, while simultaneously squeezing the composite PN water-swellable waterstop strip, so that the waterstop strip fully fits against the concrete base surface around the groove; place the upper extension section of the waterstop steel plate and the transverse wing plate in the post-poured concrete pouring area; the vertical main plate and transverse wing plate of the waterstop steel plate together make the water-stopping seepage path of the construction joint relatively straight and the construction joint extended by no less than 3 times; after locking in place, cut off the excess rod section protruding outward from the connecting screw, and apply waterproof asphalt epoxy paint to the adjusting nut and the cut surface of the screw; S5: Erect the upper pouring formwork and carry out the post-poured concrete pouring operation; perform layered and dense vibration on the concrete around the construction joint; after pouring, carry out moisture curing on the post-poured concrete until the concrete reaches the design strength. S6: Water-soluble polyurethane grout is injected into the sealed cavity formed by the longitudinal groove through the pre-reserved grouting holes on the vertical main plate of the waterstop steel plate; the grouting pressure is controlled at 0.3MPa~0.6MPa; a bottom isolation barrier is formed by the plastic strip pasted on the bottom end of the waterstop steel plate; when the adjacent pre-reserved grouting holes continuously overflow with uniform grout and the grouting of a single hole is ≥3min, it is determined that the cavity gap is fully filled and the grouting hole is sealed in time; the grouting hole is sealed. S7: Inspect the epoxy anti-corrosion primer coating on the exposed parts of the waterstop steel plate, repair and restore any damaged areas of the coating; seal the gaps on the outside of the construction joint with polymer waterproof mortar.

[0019] In summary, compared with the prior art, the above-described technical solutions conceived by this invention can achieve the following beneficial effects: (1) This invention only chiseles a shallow groove on the surface of the old concrete side to form a continuous groove. It does not require large-area chiseling of the existing concrete, which can avoid disturbance and cut off the original structural reinforcing steel, and ensure the safety reserve of the original concrete structure. It is different from the traditional remedial process of large-area chiseling and re-embedding water-stop steel plates. It reduces the waste and dust generated by chiseling, shortens the construction period, and reduces the project cost. It can be applied to the post-reinforcement treatment of construction joints of various existing reinforced concrete structures such as underground integrated pipe gallery, caisson, pipe jacking working well, box culvert, and underground garage.

[0020] (2) This invention constructs a multi-layered progressive waterproofing system consisting of pressure grouting filling and sealing, composite PN water-swellable waterstop strips for water blocking, epoxy interface sealing adhesive for interface sealing, and waterstop steel plate for physical water isolation. It blocks the groundwater seepage path step by step through multiple lines of defense. Even if a single waterproofing line fails, the remaining lines of defense can still continue to play a water-stopping role. Among them, the continuous groove is reserved for the compression and expansion deformation of the composite PN water-swellable waterstop strip, so as to avoid the waterstop strip being crushed by rigid extrusion and losing its sealing ability. The waterstop steel plate is equipped with transverse wing plates embedded in the post-cast concrete, which effectively extends the groundwater seepage path. The subsequent pressure grouting can specifically fill the micro-cracks generated by the roughened concrete interface and the hardening shrinkage of the concrete, eliminate hidden seepage channels, overcome the defects of single flexible caulking materials that are insufficient in water pressure resistance and easy to age and debond, and meet the use requirements of first-level waterproof structures in the environment of high groundwater level.

[0021] (3) The present invention uses a connecting screw and an adjusting nut to form an adjustable locking assembly. There is no need to install rebar on the original concrete. The positioning and clamping of the water-stop steel plates on both sides are achieved by bridging and clamping. This ensures that the water-stop steel plate, the composite PN water-swellable water-stop strip and the old concrete base are tightly attached, eliminating the inherent seepage gap between the post-installed components and the concrete base. The bottom end of the water-stop steel plate is equipped with a plastic strip, which forms a bottom sealing barrier after locking. During pressure grouting, it can effectively prevent the grout from leaking downwards, avoid the grout from contaminating the existing concrete below, and facilitate the establishment of a stable grouting pressure inside the grouting cavity. This ensures that the grout fully fills the gaps and solves the construction problems of grout leakage and incomplete filling in the traditional post-installed grouting process.

[0022] (4) The present invention provides an epoxy anti-corrosion primer layer on the water-facing and exposed surfaces of the water-stop steel plate, and an epoxy interface sealing adhesive layer on the bonding surface between the steel plate and the concrete. After the locking operation is completed, waterproof asphalt epoxy paint is applied to the cut screw section and the adjusting nut to provide full-range anti-corrosion protection for the metal components, alleviate the corrosion damage caused by groundwater and soil media, avoid the steel plate corrosion expansion from damaging the steel plate-concrete bonding interface, delay the aging failure of the components, and improve the long-term waterproof durability of the entire set of post-installed water-stop reinforcement structure. Attached Figure Description

[0023] Figure 1 This is a cross-sectional structural diagram of a post-concrete composite waterproofing reinforcement structure for concrete construction joints according to an embodiment of the present invention. Figure 2 This is a partial isometric exploded view of the continuous groove and the composite PN water-swellable waterstop strip of a post-installed composite waterstop reinforcement structure for concrete construction joints according to an embodiment of the present invention. Figure 3 This is a three-dimensional assembly diagram of a post-construction composite water-stop reinforcement structure for concrete construction joints, according to an embodiment of the present invention. Figure 4 This is a schematic flowchart illustrating the construction method of a post-construction composite waterproofing reinforcement structure for concrete construction joints according to an embodiment of the present invention.

[0024] In all the accompanying drawings, the same reference numerals denote the same technical features, specifically: 1-old concrete; 2-post-poured concrete; 3-construction joint; 4-roughened cleaning area; 5-groove; 6-composite PN water-swellable waterstop strip; 7-waterstop steel plate; 8-lower connecting screw; 9-upper connecting screw; 10-adjusting nut; 11-pre-reserved grouting hole; 12-plastic strip. Detailed Implementation

[0025] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the invention. Furthermore, the technical features involved in the various embodiments of this invention described below can be combined with each other as long as they do not conflict with each other.

[0026] In the description of this invention, it should be noted that, unless otherwise explicitly specified and limited, when an element is referred to as "fixed to," "set on," or "provided on" another element, it can be directly on or indirectly on the other element. When an element is referred to as "connected to" another element, it can be directly connected to or indirectly connected to the other element. The terms "mounted," "connected," "linked," and "provided with" should be interpreted broadly. For example, it can refer to a fixed connection, a detachable connection, or an integral connection; it can refer to a mechanical connection or an electrical connection; it can refer to a direct connection or an indirect connection through an intermediate medium; it can refer to the internal communication of two elements or the interaction between two elements. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0027] Furthermore, the terms "first," "second," etc., are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of this invention, "a plurality of" means two or more, unless otherwise explicitly specified.

[0028] like Figures 1-3As shown, one aspect of the present invention provides a post-installed composite water-stop reinforcement structure for concrete construction joints, applicable to post-installation water-stop reinforcement at construction joint locations between existing old concrete and post-cast concrete, mainly addressing situations where existing construction joints lack pre-embedded water-stop steel plates or where the original water-stop steel plates have failed. The structure is installed at the construction joint 3 between old concrete 1 and post-cast concrete 2 poured on top of the old concrete 1, including a continuous longitudinal groove 5 along the direction of the construction joint 3 on both sides of the old concrete 1; water-stop steel plates 7 covering the construction joint 3, respectively located at the junctions of the old concrete 1 and post-cast concrete 2 on the left and right sides of the construction joint 3; a composite PN water-swellable water-stop strip 6 longitudinally clamped between the water-stop steel plate 7 and the old concrete 1; multiple sets of connecting and locking components between the two water-stop steel plates 7; multiple reserved grouting holes 11 on the water-stop steel plate 7 communicating with the corresponding cavities of the longitudinal groove 5; and a continuous water-stop strip fixed to the water-stop steel plate 7. The bottom end face has a plastic strip 12; the water-stop steel plate 7 includes a vertical main plate and a transverse wing plate vertically disposed on the side of the vertical main plate; the lower part of the vertical main plate covers the through groove 5 on the old concrete 1, and the upper extension extends into the post-cast concrete 2; the transverse wing plate extends vertically from the side of the vertical main plate toward the post-cast concrete 2 and extends into the post-cast concrete 2, forming an interlocking water-stop section with the post-cast concrete 2, effectively extending the groundwater seepage path; the water-facing surface and exposed surface of the water-stop steel plate 7 are coated with epoxy anti-corrosion primer, and the bonding contact surface with the concrete is coated with epoxy interface sealant with a thickness of 0.8~1.2mm, realizing the integrated effect of interface sealing, bonding enhancement and anti-corrosion protection.

[0029] This invention differs from the traditional construction method of pre-embedding waterstop steel plates before concrete pouring. It adopts a reinforcement approach of post-assembly after structural formation, only requiring partial chiseling of the old concrete surface to create a continuous groove. This avoids large-scale demolition of the main concrete, does not disturb the original reinforcing steel, and causes minimal damage to the existing structure. The continuous groove 5 forms a sealed grouting cavity, providing filling space for subsequent pressure grouting and sealing microscopic water seepage channels in the concrete. It also provides deformation allowance for the composite PN water-swellable waterstop strip 6 under pressure and water expansion, preventing rigid pressure failure. A plastic strip 12 at the bottom of the waterstop steel plate 7 seals the bottom gap, forming a grout leakage barrier to ensure stable grouting cavity pressure and dense filling. The connecting locking assembly allows for bidirectional adjustment of the clamping distance between the two waterstop steel plates, ensuring a tight fit between the waterstop steel plate and the composite PN water-swellable waterstop strip against the concrete surface, eliminating interface seepage gaps.

[0030] This invention forms a multi-layered, progressive waterproofing system with defenses built from the outside in: The first line of defense is a pressure grouting and sealing line: grout is injected into the cavity of the continuous groove 5 through the pre-reserved grouting holes 11, filling the gaps between the groove cavity and the interface, sealing the micro-seepage channels caused by the roughened concrete interface and concrete shrinkage; The second line of defense is a composite PN water-swellable sealing strip line: the water-swellable sealing strip is clamped and pressed between the water-stop steel plate and the old concrete base surface, expanding and sealing the interface gaps upon contact with water, preventing groundwater from continuing to seep inward; The third line of defense is an epoxy interface sealing adhesive sealing line: The epoxy interface sealant applied to the contact surface between the water-stop steel plate 7 and the concrete seals the microscopic interface gaps between the steel plate and the concrete, blocking the seepage channels along the interface. The fourth line of defense is the physical water-stopping barrier of the water-stop steel plate: the paired water-stop steel plates 7 and their transverse flanges extending into the post-poured concrete rely on the solid water-stopping steel plates to significantly extend the seepage path of groundwater, thus achieving a physical water barrier. Multiple waterproofing lines work together and serve as backups for each other. Even if a single line of defense fails, the overall water-stopping effect can still be guaranteed, greatly reducing the probability of leakage recurrence. Multiple lines of defense progressively block groundwater infiltration, significantly improving the overall waterproofing durability of the construction joint.

[0031] This invention effectively solves the technical defects of existing post-construction joint reinforcement processes, such as large structural damage, single waterproofing system, easy leakage of grout, poor component bonding, and insufficient corrosion resistance and durability. The overall structure has strong prefabrication, convenient construction, and minimal damage to the original structure. The waterproofing reliability and long-term durability are significantly improved. It is suitable for water-stopping and reinforcement projects of existing construction joints in various underground reinforced concrete structures such as underground integrated pipe corridors, caissons, and underground garages.

[0032] Furthermore, the continuous groove 5 is excavated along both sides of the old concrete 1 along the construction joint 3. It is a local shallow groove excavation structure, which does not require large-scale removal of the old concrete main body, thus avoiding disturbance and cutting off the original structural reinforcing steel. The groove is shaped by manual labor in conjunction with a small chisel tool to remove debris and laitance from the old concrete surface. The debris and laitance generated during chiseling are washed away by high-pressure airflow and clean water. After construction, no dust or standing water shall remain in the groove. The continuous groove 5 has a shallow groove shape with a cutting width of 3-5cm and a cutting depth of 2-3cm. The continuous groove 5 mainly serves as a grouting filling cavity, forming a sealed grouting chamber between the water-stop steel plate 7 and the old concrete 1, which is filled by pressure grouting liquid in the later stage to seal the micro-seepage channels caused by the roughened surface of the concrete and the shrinkage of the concrete, thus forming the first line of waterproof defense. At the same time, the recessed space formed by the inward chiseling of the continuous groove 5 provides a deformation allowance for the composite PN water-swellable water-stop strip 6 under pressure during the locking process and for the subsequent expansion of water, so as to prevent the water-stop strip from being completely crushed by rigid extrusion and losing its water-stopping performance. The groove wall of the continuous groove 5 can also form a lateral limit on the water-stop steel plate 7, restricting the lateral displacement of the water-stop steel plate 7 and ensuring the installation positioning accuracy of the component. The continuous groove 5 is set along the entire construction joint 3, and the base surface of the groove is solid and continuous without any breaks. If there is local loose concrete damage, the loose area needs to be removed to ensure that the base surface of the groove is solid and intact.

[0033] Furthermore, the water-stop steel plates 7 are arranged in pairs on the left and right sides of the construction joint 3. Each water-stop steel plate 7 includes a vertical main plate and a transverse wing plate extending vertically from the vertical main plate toward the side of the post-cast concrete 2. The lower part of the vertical main plate covers the long groove 5 of the old concrete 1, and the upper extension of the vertical main plate, together with the transverse wing plate, extends into the interior of the post-cast concrete 2. The transverse wing plate is embedded in the post-cast concrete 2 to form an interlocking water-stop section. The steel plate structure embedded in the concrete effectively extends the groundwater seepage path and achieves physical water isolation, which is the core water-stopping component of this structure. The water-stop steel plates 7 are made of carbon structural steel (such as preferably Q235B), and the steel plate thickness is 8-10mm. After the water-stop steel plates 7 are cut, they are first sandblasted to remove rust, oxide scale, cement slurry skin and oil stains from the plate surface. The water-facing surface of the waterstop steel plate 7 and its later exposed surface are coated with epoxy anti-corrosion primer to form a metal anti-corrosion layer to resist the corrosion of groundwater and soil media. The bonding surface of the waterstop steel plate 7 in contact with the concrete is coated with epoxy interface sealant with a thickness of 0.8-1.2mm. This interface sealant can fill the micro gaps between the steel plate and the concrete, improve the bonding performance between the steel plate and the new and old concrete, and block the seepage channels along the steel plate-concrete interface.

[0034] Furthermore, the water-stop steel plates 7 are spliced ​​along their length using full welding, and the welds require rust removal and anti-corrosion treatment. The water-stop steel plates 7 have pre-drilled grouting holes 11, and plastic strips 12 are fixed at the bottom, providing a mounting point for the connecting locking components. The paired water-stop steel plates 7 are pressed tightly against the concrete base by the locking force of the connecting locking components, eliminating the seepage gap between the steel plates and the concrete.

[0035] Furthermore, the composite PN water-swellable sealing strip 6 is arranged longitudinally along the construction joint 3 between the vertical main plate of the waterstop steel plate 7 and the old concrete 1. When the locking assembly is tightened, the composite PN water-swellable sealing strip 6 is clamped between the vertical main plate of the waterstop steel plate 7 and the base surface of the old concrete 1 around the ordinary groove 5. Relying on the clearance space of the ordinary groove 5, the composite PN water-swellable sealing strip 6 can undergo compression deformation and subsequent water-swelling deformation to achieve interface sealing and form a multi-layered waterproofing. The second line of defense against waterlogging: Composite PN water-swellable waterstop strip 6 is a putty-type waterstop material with a rubber matrix and water-absorbing components; the waterstop strip cross-section specifications are 15-25mm wide and 10-20mm thick, preferably 20mm×15mm; the volume expansion rate is ≥150%; the preferred length of a single finished strip is 3m; when multiple waterstop strips are installed together, they are overlapped with an overlap length of 80-120mm. Sealant must be applied between the overlap sections to ensure a continuous seal and prevent leaks. Throughout the construction process, the composite PN water-swellable waterstop strip 6 must be shielded and protected to prevent pre-expansion of the waterstop strip before concrete pouring, thus preventing premature expansion and loss of its water-stopping effectiveness. When groundwater seeps inward along the construction joint, it comes into contact with the composite PN water-swellable waterstop strip 6. The water-absorbing components inside the waterstop strip expand in volume upon contact with water, and under the pre-compression stress of locking and clamping, they squeeze the interface gap between the waterstop steel plate 7 and the old concrete 1, preventing the water from continuing to seep inward. The continuous groove 5 provides deformation allowance, preventing the waterstop strip from being completely crushed by rigid compression and losing its expansion capacity. Even if the structure undergoes slight settlement deformation later, the waterstop strip can still adaptively seal the small cracks by relying on its expansion performance, and has a certain self-healing ability for the cracks.

[0036] Furthermore, the composite PN water-swellable waterstop strip 6 is adhered and fixed to the side of the waterstop steel plate 7 facing the construction joint 3 by epoxy interface sealing adhesive. Throughout the construction process, proper shielding and protection are required to prevent the waterstop strip from prematurely contacting water and undergoing pre-expansion, which could cause the waterstop effect to fail. When groundwater seeps into the construction joint gap, the waterstop strip expands upon contact with water, compressing the gap between the waterstop steel plate 7 and the old concrete 1, preventing further inward seepage of water. Under the locking action of the connecting locking components, the waterstop strip is compressed and deformed, tightly fitting against the groove wall of the continuous groove 5, further eliminating interface gaps and improving the sealing and water-stopping effect.

[0037] Furthermore, multiple sets of the connecting locking components are bridging between the left and right waterstop steel plates 7 to achieve positioning, spacing adjustment, and clamping locking of the waterstop steel plates 7 on both sides, forming an adjustable clamping and fixing system. The connecting locking components include an upper connecting screw 9, a lower connecting screw 8 passing between the two waterstop steel plates 7, and an adjusting nut 10 assembled at the end of each connecting screw. The upper connecting screw 9 and the lower connecting screw 8 are arranged in layers along the height direction of the construction joint 3. The adjusting nut 10 is used to adjust the tightness of the fit between the waterstop steel plate 7 and the old concrete 7. The upper connecting screw 9 and the lower connecting screw 8 are both made of round steel with a diameter of 10-14mm, and are arranged in layers and staggered in a quincunx pattern along the height direction of the construction joint 3. The spacing between each connecting screw on the same horizontal plane is 0.8-1.2m.

[0038] Furthermore, external threads are machined at both ends of the upper connecting screw 9 and the lower connecting screw 8, with a 10cm to 20cm threaded section reserved according to the cross-sectional dimensions of the concrete structure, so that the adjusting nut 10 can be adjusted spirally to ensure that the steel plate is as close as possible to the concrete surface; each connecting screw passes horizontally through the two water-stop steel plates 7, and adjusting nuts 10 are installed at both ends of each connecting screw; by turning the adjusting nuts 10 at both ends, the distance between the two water-stop steel plates 7 can be adjusted, so that the water-stop steel plates 7 press tightly against the old concrete base surface, while extruding the composite PN water-swellable water-stop strip 6, so that the water-stop strip fully adheres to the concrete base surface and eliminates the interface seepage gap.

[0039] Furthermore, after locking and positioning, the excess sections of the upper connecting screw 9 and the lower connecting screw 8 extending outward are cut off. Waterproof asphalt epoxy paint is then applied to the cutting surfaces of the adjusting nut 10 and the upper connecting screw 9 and the lower connecting screw 8 to prevent corrosion and corrosion of the screws and nuts in the underground environment. By setting up layered connecting screws (upper connecting screw 9 and lower connecting screw 8), the two waterstop steel plates 7 are clamped and fixed at multiple points, solving the problem of the post-installed waterstop steel plate 7 being difficult to fit tightly with the existing concrete. This eliminates the need for rebar installation in the original structure, relying on cross-clamping to achieve component fixation with minimal damage to the old concrete.

[0040] Furthermore, the reserved grouting holes 11 are used to compensate for the fine cracks caused by the hardening shrinkage of concrete and the small gaps in the roughened interface, achieving secondary reinforcement and water stoppage. Multiple reserved grouting holes 11 are arrayed on the vertical main plate of the water-stop steel plate 7, penetrating the water-stop steel plate body. The holes are connected to the cavity of the rear continuous groove 5, serving as grouting channels and observation channels for pressure grouting. The reserved grouting holes 11 are formed by mechanical drilling, with a hole diameter of 3-5 cm. The spacing between adjacent reserved grouting holes 11 along the construction joint direction is 35-50 cm. The reserved grouting holes 11 should avoid the vertical position where the screw connecting the locking assembly is located to prevent drilling from damaging the screw. After the post-cast concrete 2 has cured to the design strength, grouting material (such as water-soluble polyurethane grout) is injected into the cavity of the through groove 5 through the reserved grouting hole 11. During the grouting operation, the filling degree of the cavity can be judged by the grout discharge status of adjacent grouting holes. When the adjacent holes continuously overflow with uniform grout, it indicates that the gap has been fully filled. Then the grouting hole is sealed to ensure the integrity of the steel plate surface.

[0041] Furthermore, the plastic strip 12 is continuously and fixed to the bottom lower surface of the waterstop steel plate 7, positioned at the contact surface between the waterstop steel plate 7 and the bottom of the old concrete 1, primarily serving as an isolation layer to prevent grout leakage during injection. The plastic strip 12 is a self-adhesive EVA foam sealing strip, possessing a certain degree of compression resilience. The plastic strip 12 is continuously laid along the direction of the construction joint 3, with an overlap length of not less than 5cm when segmented, ensuring a continuous and uninterrupted bottom sealing barrier. After being locked and tightened by the connecting locking components, the plastic strip 12 is compressed and deformed, tightly sealing the bottom gap between the bottom end of the waterstop steel plate 7 and the old concrete 1. During pressure grouting, it prevents the grout from flowing downwards from the bottom of the waterstop steel plate 7, avoiding grout overflow and contamination of the lower old concrete, ensuring a stable grouting pressure is established inside the grouting cavity, and guaranteeing that the grout fully fills the groove and interface gap. Simultaneously, the plastic strip 12 can buffer the hard contact between the waterstop steel plate 7 and the concrete, mitigating the risk of interface cracking caused by minor vibrations.

[0042] Furthermore, the present invention also provides a quantitative control method for the water-stopping performance of the above-mentioned post-installed composite water-stopping reinforcement structure for concrete construction joints. This method is used to quantitatively determine the tightening torque of the connecting locking components, the pre-compression state of the composite PN water-swellable water-stopping strip 6, the fullness of grout filling, and the overall water-stopping reliability during construction, ensuring that each waterproofing line works collaboratively and achieves the designed water-stopping target. Specifically, it includes the following control algorithm: This invention utilizes paired water-stop steel plates 7, with their vertical main plates and horizontal flanges embedded in the post-cast concrete 2, to physically bend and extend the seepage path of groundwater along the construction joint 3 and the steel plate-concrete interface. To quantitatively control the structural water-stopping capacity of the water-stop steel plates 7, an equivalent physical water-stopping seepage path length is defined. for: in: : The equivalent physical seepage prevention diameter formed by the double-sided water-stop steel plates, in meters; :The effective water-blocking height of the vertical main plate of the waterstop steel plate 7 is the height of the vertical main plate located in the influence zone of construction joint 3 and the boundary between old and new concrete, in meters; : Effective height of the extension section of the vertical main board embedded in the post-cast concrete 2, in meters; : Width of the transverse flange extending into / embedded in the post-cast concrete 2, in meters; The equivalent return width of the waterstop strip provided by the continuous groove 5 is the effective projected dimension in the groove opening width direction, in meters. The reduction coefficient for the seepage path of the embedded section in the post-cast concrete is taken as 0.85~1.00, considering the density of the concrete wrapping. The reduction coefficient for interlocking waterstop of the transverse flange plate, taking into account the interlocking quality between the flange plate and the post-poured concrete, is taken as 0.70~0.90; : The deformation allowance correction coefficient of the through groove 5 and the waterstop strip interface is taken as 0.40~0.60; Coefficient 2 represents the double-sided water-blocking path formed by the pair of waterstop steel plates 7 on the left and right sides of the construction joint 3. Furthermore, the water-stopping reinforcement coefficient of the steel plate structure is defined as follows: ,in: The reinforcement factor of the seepage path extension of the waterstop steel plate structure relative to a straight construction joint; The straight seepage diameter length of construction joint 3 when no waterstop steel plate 7 and waterstop strip 6 are installed can be taken as the characteristic length in the exposed thickness direction of the construction joint, in meters.

[0043] By controlling Preferred The geometric and physical waterproofing of the waterstop steel plate 7 is determined to meet the design requirements. That is, the vertical main plate and the horizontal flange of the waterstop steel plate 7 together make the waterstop seepage path of the construction joint 3 extend by no less than 3 times compared to the relatively straight construction joint.

[0044] Furthermore, to ensure close contact between the waterstop steel plate 7 and the old concrete base surface 1, and to ensure that the composite PN water-swellable waterstop strip 6 obtains stable pre-stress, the single-point normal clamping force provided by the connecting locking assembly... The torque-pitch relationship of adjusting nut 10 is determined as follows: ,in: : Normal clamping force generated at the position of a single adjusting nut 10 and its corresponding connecting screw, in N; : The torque applied when tightening the adjusting nut 10, in N·m; : Pitch of the external thread of the connecting screw, in meters; The comprehensive coefficient of thread friction, taking into account the minor lubrication and rust prevention of the epoxy interface sealant, is taken as 0.12 to 0.18. Torque-axial force conversion correction factor, taking into account screw bending, bore wall contact and deformation of both sides of the steel plate, is taken as 1.05 to 1.25.

[0045] Along the direction of construction joint 3, the average clamping force obtained per unit length of waterstop steel plate 7 is: in: : Average linear clamping force of the waterstop steel plate 7 on the old concrete base surface 1 and the waterstop strip 6, unit N / m; The total number of effective action points of the upper connecting screw 9 and the lower connecting screw 8 per meter on the same side; : The deviation angle between the axis of the connecting screw and the normal direction of the waterstop steel plate 7, which is taken as 0° for ideal installation; Calculate the unit length, taking 1.0m. Corresponding initial preload stress for waterstop strip 6: ,in: : Effective pressure-bearing width of waterstop strip 6, in meters; Initial prestress of composite PN water-swellable sealing strip 6, unit: Pa; : Effective load width of waterstop strip 6, in meters, taken as the actual contact projection width in the width direction of the waterstop strip.

[0046] Construction control must meet the following requirements: If the pressure is below the lower limit, the interface gap will not be eliminated sufficiently; if it is above the upper limit, the clearance space of the long groove 5 will be excessively compressed, affecting the subsequent self-adaptive ability to expand when exposed to water. That is, the adjusting nut 10 is configured to control the pre-stress of the waterstop strip at 0.15~0.35MPa.

[0047] Furthermore, considering the compression deformation of the waterstop strip 6 within the continuous groove 5 and its subsequent expansion upon contact with water, the usable sealing function is defined. : ,in: Waterstop strip 6 can be used to effectively seal micro-gaps at interfaces, with the unit being J; : Equivalent compression-expansion modulus of composite PN water-swellable sealing strip 6, unit Pa; Initial compressive strain after installation and locking. , This represents the compression amount in the thickness direction. Initial thickness of the waterstop strip; The volume expands upon contact with water, resulting in an equivalent change. This is determined by the volume expansion rate. control, ; Calculate the volume of the waterstop strip. ; Initial width of the waterstop strip, in meters; Initial thickness of the waterstop strip, in meters (m). : Calculate the length of the segment, in meters; :The initial maximum gap between the waterstop steel plate 7 and the old concrete 1, in meters; : The maximum allowable deformation margin for the continuous groove 5 and its construction is the combined value of the groove depth and the compression allowance of the waterstop strip, in meters; volume expansion rate. ,Right now When substituting decimals or percentages, convert them to multiples; for example, 150% is converted to 1.5. Interface self-sealing judgment index: ; in: Interface self-sealing index; : Projected contact area between the waterstop strip and the old concrete / steel plate, unit ; The equivalent stiffness parameters of the micro-area on the surface of old concrete 1 are calculated based on actual measurements or by taking the elastic modulus of concrete 3 of the same strength grade, in Pa.

[0048] Control conditions: This indicates that the waterstop strip has sufficient capacity to seal the interface gaps and achieve self-adaptive sealing under pre-compression and water-swelling conditions; The continuous groove provides compression-expansion margin for the waterstop strip, enabling it to compact interface gaps and adaptively seal micro-cracks under pre-compression and water-expanding conditions.

[0049] Furthermore, water-soluble polyurethane grout is injected into the elongated groove 5 cavity and the steel plate-concrete interface through the reserved grouting hole 11 to define the cavity filling fullness. : ,in: : Grouting cavity filling fullness, target ; Actual volume of injected grout, unit ; The effective retained volume, constrained by the plastic strip 12 and the sealing interface, can be repeatedly maintained by pressure, unit ; Theoretically, the filling volume of the continuous groove 5, grouting holes 11, connecting channels and interface gaps is [unit missing]. ; The equivalent volume of the concrete interface side void is calculated based on compensation for the grouting pressure-stabilized section, per unit. .

[0050] Grouting pressure meets: ,in, Grouting pressure, controlled as follows: ; : Initial hydrostatic / air resistance reference pressure of the filling cavity, unit ; : The increase in flow resistance of slurry in channels, grooves, cavities, and interfacial gaps, expressed in units of ; The increase in reverse sealing resistance caused by the deformation of plastic strip 12 and waterstop strip 6, in units of ; When determining continuous grout overflow from adjacent grouting holes, a time window is introduced: in, Single-hole grouting duration, in units ; : Determine the flow rate or visible continuous overflow of grout by observing the grout overflow from adjacent observation / grouting holes; When a uniform grout continuously overflows from adjacent holes and grouting in a single hole lasts for ≥3 minutes, the entire long groove cavity is determined to be fully filled and the grouting hole is sealed, thus sealing the current hole.

[0051] Furthermore, considering the corrosion resistance of Q235B carbon structural steel in groundwater and soil media, and combining the reinforcement effects of epoxy anti-corrosion primer, epoxy interface sealing adhesive, waterproof asphalt epoxy paint, and grouting isolation, a metal corrosion correction factor is defined: ,in, : Comprehensive correction factor for corrosion resistance; Contribution coefficient of epoxy anti-corrosion primer coating, taken from the integrity of coating application. ; Contribution coefficient of epoxy interface sealant, adhesive layer thickness Time to take ; The isolation coefficient of the impregnation ring after filling the grouting cavity is calculated as follows: Values, and not exceeding ; Repair coefficient of waterproof asphalt epoxy paint on the cut surface and nut; for complete repair, take... Unrepaired ; After the grouting is fully filled, the interface between the waterstop steel plate and the concrete is isolated by the grout, which, together with the epoxy anti-corrosion primer, epoxy interface adhesive and waterproof asphalt epoxy paint on the nut / screw section, forms a metal anti-corrosion system. The expression for the comprehensive reliability index of the water-stopping structure is: ,in: : Comprehensive reliability index of post-construction composite waterproofing reinforcement structure; : Reference top compressive stress, taken as ; : Preload stress influence index, taken as This reflects that excessive preloading can also sacrifice the expansion margin of the waterstop strip; Construction quality control objectives: Preferred: ;when When the above requirements are met, the post-installed composite water-stopping reinforcement structure in this section is deemed to have achieved the designed water-stopping reliability.

[0052] The above control algorithm couples the physical extension of the seepage path of the steel plate, the locking pre-compression, the compression / false expansion sealing work of the PN waterstop strip, the filling of the grouting cavity, and the anti-corrosion correction into the same reliability evaluation model; in particular, it introduces the deformation allowance correction coefficient of the through groove 5. Waterstop strip sealing function With interface self-sealing index and grout fullness Corrosion resistance coefficient The feedback relationship allows for the quantifiable adjustment of construction parameters: the torque of adjusting nut 10, the spacing of connecting bolts, the specifications and overlap of the waterstop strip, the grouting pressure and time, the sealing of the plastic strip 12, and the thickness of the epoxy adhesive layer can all be determined by the target parameters. or The reverse control method solves technical problems such as poor adhesion between the post-installed waterstop steel plate and the old concrete, grout leakage, premature / excessive compression of the waterstop strip, and corrosion of metal parts.

[0053] like Figure 4 As shown, a second aspect of the present invention provides a construction method for a post-installed composite waterproofing reinforcement structure for concrete construction joints, comprising the following steps: S1. Construction Joint Base Surface Pretreatment: The entire construction joint 3, where the old concrete 1 and the post-cast concrete 2 meet, is roughened and cleaned to remove laitance, loose aggregate, oil, and debris. Along the direction of construction joint 3, a continuous groove 5 is formed on both sides of the old concrete 1 using manual labor and a small roughening machine. This process is a localized, shallow excavation; the reinforcing steel bars inside the old concrete 1 must not be damaged, and large-area removal of the existing main concrete is prohibited. High-pressure airflow combined with water rinsing is used to remove dust and debris from the inside of the continuous groove 5 and the interface of construction joint 3. The base surface is allowed to air dry naturally, ensuring no standing water remains. The excavation width of the continuous groove 5 is 3-5cm, and the excavation depth is 2-3cm. If there are any loose or damaged areas of concrete within the work area, they must be removed to ensure the groove base surface is solid and intact, and the groove runs continuously along the entire construction joint 3 without any breaks. S2. Pre-treatment of waterstop steel plate components: Sandblasting is performed on the paired waterstop steel plates 7 to remove rust, scale, cement slurry, and oil stains from the plate surface; epoxy anti-corrosion primer is applied to the water-facing surface and the exposed surface of the waterstop steel plates 7; epoxy interface sealant with a thickness of 0.8mm to 1.2mm is evenly applied to the bonding surface of the waterstop steel plates 7 in contact with the concrete; pre-drilled grouting holes 11 through the waterstop steel plate 7 according to the design parameters, avoiding the vertical placement of the connecting bolts of the subsequent connecting locking components; plastic strips 12 are pasted along the entire length of the bottom lower end face of the waterstop steel plates 7; if splicing is required along the length of the waterstop steel plates 7, full welding process is adopted, and after welding, the weld is derusted and repaired with anti-corrosion treatment; S3. Waterstop Strip Installation: The composite PN water-swellable waterstop strip 6 is pasted and fixed onto the side of the waterstop steel plate 7 facing the construction joint 3. The waterstop strip is continuously laid along the construction joint 3, with overlapping connections at the joints. The overlap length is not less than 100mm, and sealant is applied to the overlap surface to ensure a continuous seal without any leaks. The waterstop strip is placed 5-8cm away from the construction joint 3 in the old concrete 1. After the waterstop strip is pasted, protective measures are taken to shield it to prevent pre-expansion due to contact with water during construction, thus preventing premature failure of the waterstop effect. The composite PN water-swellable waterstop strip 6 has a cross-sectional width of 15mm-25mm and a thickness of 10mm-20mm, preferably 20mm×15mm, with a volume expansion rate ≥150%; the length of a single strip is 3-5m. S4. Positioning and Adjustable Locking of Waterstop Steel Plate: The waterstop steel plate 7, equipped with the composite PN water-swellable waterstop strip 6 and plastic strip 12, is positioned and installed, ensuring that the lower part of the vertical main plate of the waterstop steel plate 7 covers the continuous groove 5, and the plastic strip 12 at the bottom of the waterstop steel plate 7 is tightly attached to the surface of the old concrete 1. Upper connecting screws 9 and lower connecting screws 8, forming a locking assembly, are inserted between the two waterstop steel plates 7 in layers, and adjusting nuts 10 are installed at both ends of each connecting screw. Both the upper connecting screws 9 and lower connecting screws 8 are made of round steel with a diameter of 10mm to 14mm, and are arranged in a staggered, quincunx pattern along the height of the construction joint 3, with a spacing of 0.8m to 1.2m. A 10cm allowance is left at both ends of the connecting screws according to the cross-sectional dimensions of the concrete structure. A 20cm threaded section is provided so that the adjusting nut 10 can be adjusted spirally to ensure that the steel plate is in close contact with the concrete surface as much as possible. Tighten the adjusting nuts 10 at both ends to adjust the clamping distance between the two water-stop steel plates 7, so that the water-stop steel plates 7 press firmly against the old concrete 1 base surface, and at the same time squeeze the composite PN water-swellable water-stop strip 6, so that the water-stop strip fully fits the concrete base surface around the groove 5, eliminating the interface seepage gap. The upper extension section of the water-stop steel plate 7 and the transverse wing plate are placed in the post-cast concrete 2 pouring area, so as to be buried in the post-cast concrete to extend the groundwater seepage path. After locking in place, the excess rod sections of the upper connecting screw 9 and the lower connecting screw 8 that extend outward are cut off, and waterproof asphalt epoxy paint is applied to the adjusting nut 10 and the cut surface of the screw to complete the anti-corrosion treatment. S5. Post-concrete pouring construction: Erect the upper pouring formwork and carry out the post-concrete 2 pouring operation; for the concrete around the construction joint 3, layer-by-layer dense vibration is carried out to ensure that the post-concrete 2 is fully bonded and compacted with the old concrete 1 and the waterstop steel plate 7; after the pouring is completed, the post-concrete 2 is moisturized and cured until the concrete reaches the design strength. S6. Pressure Grouting for Water Stopping and Reinforcement: After the post-poured concrete 2 has cured to its design strength, water-soluble polyurethane grout is injected into the sealed cavity formed by the longitudinal groove 5 through the reserved grouting holes 11 opened on the vertical main plate of the water-stop steel plate 7. The grouting pressure is controlled at 0.3MPa~0.6MPa. The plastic strip 12 attached to the bottom of the water-stop steel plate 7 forms a bottom isolation barrier to prevent the grout from flowing downwards and to avoid contaminating the lower old concrete 1, thus maintaining the stability of the grouting pressure inside the grouting cavity. When the adjacent reserved grouting holes 11 continuously overflow with uniform grout, it is determined that the cavity gap is fully filled, and the grouting holes are sealed in time (when the adjacent holes continuously overflow with uniform grout and the single hole grouting time is ≥3min, it is determined that the longitudinal groove cavity is fully filled and the grouting hole is sealed). After the grouting operation is completed, the grouting holes are sealed to ensure the integrity of the surface of the water-stop steel plate 7. Among them, the reserved grouting holes 11 have a diameter of 2cm to 4cm and are laid out at a spacing of 30cm to 40cm along the construction joint; the plastic strip 12 is a self-adhesive EVA foam sealing strip with a segmented overlap length of 4cm to 6cm. S7. Corrosion prevention and finished product sealing treatment: Inspect the epoxy anti-corrosion primer coating on the exposed parts of the waterstop steel plate 7, and repair and restore any damaged parts of the coating; seal the gaps on the outside of the construction joint 3 with polymer waterproof mortar, and complete all construction procedures for the post-installed composite waterstop reinforcement of this concrete construction joint.

[0054] Further, in step S4, the adjusting nut 10 is tightened to give the composite PN water-swellable waterstop strip 6 an initial pre-stress of 0.15MPa to 0.35MPa; in step S6, when the adjacent reserved grouting holes continuously overflow with uniform grout and the single hole continues to grout for no less than 3 minutes, it is determined that the through groove cavity is fully filled and the grouting hole is sealed; wherein, the waterstop seepage path formed by the vertical main plate and the horizontal wing plate of the waterstop steel plate 7 is extended by no less than 3 times relative to the straight construction joint.

[0055] To quantitatively characterize the multi-layered waterproofing synergistic effect, structural compaction adaptability, and grouting pressure stabilization and filling effect of the post-installed composite waterproofing structure of this invention, and to improve the scientific nature and engineering controllability of the technical solution of this invention, this invention innovatively sets up a post-installed composite waterproofing coupling waterproofing performance evaluation method at construction joints, the specific formula of which is: This invention aims to solve the technical problems of traditional remedial processes for existing concrete construction joints that are missing or damaged by embedded waterstop steel plates. These problems include large-area chiseling that easily damages the original structure, a single waterproofing line, grout leakage, poor adhesion of post-installed components, and insufficient corrosion resistance. This invention only requires localized grooving of the old concrete surface, eliminating the need for large-area chiseling and avoiding disturbance to the original reinforcing steel. Multiple waterproofing lines work synergistically, resulting in a low risk of leakage recurrence. It allows for a tight fit between the component and the concrete substrate, ensuring stable grouting pressure. With a complete metal corrosion protection system, it effectively improves the construction quality and long-term waterproofing durability of post-installed reinforcement of existing construction joints in underground structures. It is suitable for various underground reinforced concrete structures such as underground utility tunnels, caissons, and underground parking garages.

[0056] Those skilled in the art will readily understand that the above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A post-construction composite waterproofing reinforcement structure for concrete construction joints, located at the construction joint (3) between old concrete (1) and post-construction concrete (2) poured on the upper side of the old concrete (1), characterized in that: The system includes a continuous groove (5) along the construction joint (3) on both sides of the old concrete (1), a waterstop steel plate (7) set at the junction of the old concrete (1) and the post-cast concrete (2) on the left and right sides of the construction joint (3) and covering the construction joint (3), a composite PN water-swellable waterstop strip (6) clamping and arranged between the waterstop steel plate (7) and the old concrete (1) along the longitudinal direction of the construction joint (3), multiple sets of connecting and locking components spanning between the two waterstop steel plates (7), multiple reserved grouting holes (11) opened on the waterstop steel plate (7) and communicating with the cavity of the corresponding continuous groove (5), and a plastic strip (12) fixed to the bottom lower end face of the waterstop steel plate (7) throughout its length; the waterstop steel plate (7) includes a vertical main plate and a transverse wing plate vertically set on the side of the vertical main plate; the lower part of the vertical main plate covers the continuous groove (5) on the old concrete (1), and the upper part of the vertical main plate extends into the groove. The transverse flange extends vertically from the main vertical plate toward the side of the post-cast concrete (2) and extends into the post-cast concrete (2) to form an interlocking water-stop section; the water-facing surface and exposed surface of the water-stop steel plate (7) are coated with epoxy anti-corrosion primer, and the bonding contact surface with the concrete is coated with epoxy interface sealing adhesive; the through groove (5) constitutes a closed grouting cavity and provides deformation allowance for the composite PN water-swellable water-stop strip (6) to be compressed and expand when exposed to water. The amount; the plastic strip (12) is used to press and seal the gap between the bottom of the water-stop steel plate (7) and the old concrete (1) to form a grouting anti-leakage barrier; the connection locking assembly is used to adjust the distance of the water-stop steel plates on both sides, so that the water-stop steel plate and the composite PN water-swellable water-stop strip are pressed and adhered to the old concrete base surface; the structure is used to perform post-installed water-stop reinforcement on existing construction joints that have been formed, missing or damaged pre-embedded water-stop steel plates, without the need to remove a large area of ​​the old concrete main body.

2. The post-installed composite waterproofing reinforcement structure for concrete construction joints according to claim 1, characterized in that: The connecting locking assembly includes an upper connecting screw (9), a lower connecting screw (8), and adjusting nuts (10) fitted at both ends of each connecting screw. The upper connecting screw (9) and the lower connecting screw (8) are bridging and passing between two water-stop steel plates (7), and are arranged in layers and staggered in a quincunx pattern along the height direction of the construction joint (3). The clamping distance between the two water-stop steel plates is adjusted by the adjusting nuts (10). After locking, the excess protruding sections of the upper connecting screw and the lower connecting screw are cut off, and anti-corrosion coatings are applied to the cut surfaces of the screws and the surfaces of the adjusting nuts.

3. The post-installed composite waterproofing reinforcement structure for concrete construction joints according to claim 2, characterized in that: The upper connecting screw (9) and the lower connecting screw (8) are made of round steel, and the two ends of the screw are machined with external thread sections of 10-20cm; the spacing between the screws on the same horizontal plane is 0.8m-1.2m; the anti-corrosion coating is a waterproof asphalt epoxy paint anti-corrosion layer.

4. A post-installed composite waterproofing reinforcement structure for concrete construction joints according to any one of claims 1-3, characterized in that: The width of the through groove (5) is 3-5cm; the depth of the through groove is 2-3cm; the through groove runs through the entire construction joint, the base of the groove is solid, and the groove wall forms a lateral limit on the water-stop steel plate (7).

5. A post-installed composite waterproofing reinforcement structure for concrete construction joints according to any one of claims 1-3, characterized in that: The composite PN water-swellable sealing strip (6) is a putty-type sealing material with a rubber matrix and water-absorbing components; its volume expansion rate is ≥150%. The composite PN water-swellable waterstop strip (6) is pasted and fixed to the surface of the waterstop steel plate (7) facing the construction joint (3); the composite PN water-swellable waterstop strip (6) is set at a distance of 5-8cm from the construction joint in the old concrete. When the locking assembly is locked, the composite PN water-swellable waterstop strip (6) is clamped between the vertical main plate of the waterstop steel plate (7) and the base surface of the old concrete around the long groove (5); when multiple waterstop strips are installed together, they are lapped, and the lap length of the waterstop strip is not less than 100mm; the lapped parts are coated with sealant.

6. A post-installed composite waterproofing reinforcement structure for concrete construction joints according to any one of claims 1-3, characterized in that: After the connecting locking assembly is locked, the adjusting nut (10) is configured such that the initial preload stress of the composite PN water-swellable sealing strip (6) is 0.15MPa to 0.35MPa.

7. A post-installed composite waterproofing reinforcement structure for concrete construction joints according to any one of claims 1-3, characterized in that: The waterstop steel plate (7) is made of carbon structural steel. The waterstop steel plate (7) is fully welded at the splicing position along the length direction, and the weld is provided with a rust removal and anti-corrosion layer. The vertical main plate and the horizontal wing plate of the waterstop steel plate (7) together make the waterstop seepage path of the construction joint (3) extend by no less than 3 times compared with the straight construction joint.

8. A post-installed composite waterproofing reinforcement structure for concrete construction joints according to any one of claims 1-3, characterized in that: The diameter of the reserved grouting hole (11) is 3-5cm, and the spacing between adjacent reserved grouting holes along the construction joint is 35cm-50cm.

9. A post-installed composite waterproofing reinforcement structure for concrete construction joints according to any one of claims 1-3, characterized in that: The plastic strip (12) is a self-adhesive EVA foam sealing strip, and the overlap length of the plastic strip is not less than 5cm. After the plastic strip is pressed by the connecting locking component, it undergoes elastic deformation to isolate and block the downward flow channel of the grout.

10. A construction method for a post-installed composite waterproofing reinforcement structure for concrete construction joints, characterized in that, The reinforcement structure as described in any one of claims 1-9 is applied, comprising the following steps: S1: Carry out a roughening and cleaning operation along the entire construction joint (3) at the junction of the old concrete (1) and the post-cast concrete (2), removing laitance, loose aggregate, oil stains and debris from the joint surface; along the direction of the construction joint (3), use manual labor and small roughening tools to continuously chisel to form a continuous groove (5) on both sides of the old concrete (1); remove dust and debris from the inside of the continuous groove (5) and the interface of the construction joint (3), and let the base surface dry naturally; S2: Sandblasting is performed on the paired waterstop steel plates (7) to remove rust; epoxy anti-corrosion primer is applied to the water-facing surface and the exposed surface of the waterstop steel plates (7) in the future; epoxy interface sealant with a thickness of 0.8mm to 1.2mm is evenly applied to the bonding surface of the waterstop steel plates (7) in contact with the concrete; multiple reserved grouting holes (11) are drilled through the waterstop steel plate (7) and connected to the through groove (5); plastic strips (12) are pasted along the bottom of the waterstop steel plate (7) along the entire length. S3: The composite PN water-swellable waterstop strip (6) is pasted and fixed on the side of the waterstop steel plate (7) facing the construction joint (3); the waterstop strip is continuously laid along the direction of the construction joint (3), and the waterstop strip is connected by overlapping at the joints, with an overlap length of not less than 100mm, and sealant is applied to the overlap section; after the waterstop strip is pasted, the waterstop strip is covered and protected. S4: Install the waterstop steel plate (7) equipped with the composite PN water-swellable waterstop strip (6) and plastic strip (12) in place, so that the lower part of the vertical main plate of the waterstop steel plate (7) is covered with the long groove (5), and the plastic strip (12) at the bottom of the waterstop steel plate (7) is in close contact with the surface of the old concrete (1); the upper connecting screw (9) and the lower connecting screw (8) of the connecting locking assembly are inserted between the two waterstop steel plates (7) in layers, and adjusting nuts (10) are installed at both ends of each connecting screw; tighten the adjusting nuts (10) at both ends to adjust the clamping distance between the two waterstop steel plates (7) so that the waterstop steel plate (7) presses the old concrete tightly. (1) Base surface, and simultaneously squeeze the composite PN water-swellable waterstop strip (6) to make the waterstop strip fully fit the concrete base surface around the groove, and the initial pre-stress of the composite PN water-swellable waterstop strip (6) is controlled at 0.15MPa~0.35MPa; the upper extension section of the waterstop steel plate (7) and the transverse wing plate are placed in the post-cast concrete (2) pouring area; the vertical main plate of the waterstop steel plate (7) and the transverse wing plate together make the waterstop seepage path of the construction joint (3) extend by no less than 3 times compared to the straight construction joint; after locking in place, cut off the excess rod section that extends outward from the connecting screw, and apply waterproof asphalt epoxy paint to the adjusting nut (10) and the screw cutting surface; S5: Set up the upper pouring formwork and carry out the pouring operation of post-poured concrete (2); carry out layered and dense vibration of the concrete around the construction joint (3); after the pouring is completed, carry out moist curing of post-poured concrete (2) until the concrete reaches the design strength. S6: Water-soluble polyurethane grout is injected into the closed cavity formed by the through groove (5) through the reserved grouting hole (11) opened on the vertical main plate of the water-stop steel plate (7); the grouting pressure is controlled at 0.3MPa~0.6MPa; a bottom isolation barrier is formed by the plastic strip (12) pasted on the bottom end of the water-stop steel plate (7); when the adjacent reserved grouting hole (11) continuously overflows with uniform grout and the single hole grouting is ≥3min, it is determined that the cavity gap is fully filled and the grouting hole is sealed in time; the grouting hole is sealed. S7: Inspect the epoxy anti-corrosion primer coating on the exposed part of the waterstop steel plate (7), repair and restore the damaged parts of the coating; seal the gaps on the outside of the construction joint (3) with polymer waterproof mortar.

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