Splicing and construction process of steel sleeve for structural reinforcement

Abstract

The invention provides a splicing and construction process of a steel sleeve for structural reinforcement, and belongs to the technical field of splicing and construction, and the splicing and construction process comprises the following steps: step 1, carrying out modular splitting design on the steel sleeve for structural reinforcement; 2, after the modular split design is conducted, pre-installed sealing system design is conducted on the steel sleeve for structural reinforcement; 3, after the preassembled sealing system is designed, the annular space and grouting parameters are standardized; and 4, after the annular space and grouting parameters are standardized, the construction technology is optimized. The reinforcing construction efficiency can be improved, the operation risk is reduced, and meanwhile it is ensured that the reinforcing quality is stable and controllable.

Description

Technical Field

[0001] This invention belongs to the field of assembly and construction technology, specifically relating to the assembly and construction process of a steel sleeve for structural reinforcement. Background Technology

[0002] During the long-term service of large structural components (such as offshore wind farm pile legs, wharf pile foundations, and hydraulic structure columns), they are susceptible to damage such as concrete corrosion and spalling, crack propagation, and decreased structural bearing capacity due to harsh environmental conditions (seawater corrosion, tidal erosion, temperature changes), accumulated loads, and material aging. These issues seriously threaten the safety and service life of the engineering structure. Traditional reinforcement techniques have many limitations: The integral steel sleeve is too heavy and requires large hoisting equipment for installation. In confined spaces (such as dock pile foundation groups, inside jackets) or complex operating scenarios such as offshore wind farms, it is difficult to bring the equipment into the site, resulting in low installation efficiency and high safety risks. The on-site formwork and pouring process is complicated, requiring steps such as formwork erection, vibration, curing, and formwork removal. The construction period is long and is greatly affected by ambient temperature and humidity, which can easily lead to problems such as incomplete grouting and grout leakage. The existing technical solutions, such as the one with patent publication number "CN222008890U", involve a prefabricated steel sleeve sealing structure that is mostly a temporary on-site pasted sealing strip. The sealing reliability is poor, and it is easy to cause excessive pressure and grout bursting or grout loss during the grouting process due to uneven bolt tightening or insufficient sealing strip fit, which affects the reinforcement quality. There is a lack of unified standards for the design of annular space dimensions and the control of grouting pressure. In some projects, the space is too small, resulting in insufficient fluidity of grouting materials, or improper pressure values ​​causing secondary damage to the structure. It is difficult to balance the reinforcement effect and construction safety. Summary of the Invention

[0003] To address the shortcomings of existing technologies, this invention provides an assembly and construction process for steel sleeves used in structural reinforcement. This process is modular, reliably sealed, and adaptable to complex scenarios, aiming to improve reinforcement construction efficiency, reduce operational risks, and ensure stable and controllable reinforcement quality.

[0004] The present invention employs the following technical solution.

[0005] An assembly and construction process for a steel sleeve for structural reinforcement includes: Step 1: Modular design of the steel sleeve for structural reinforcement; Step 2: After modular design, design a pre-installed sealing system for the steel sleeve used for structural reinforcement; Step 3: After designing the pre-installed sealing system, standardize the annular space and grouting parameters; Step 4: After standardizing the annular space and grouting parameters, optimize the construction process.

[0006] Furthermore, in step 1, the structural reinforcement steel sleeve used as the external reinforcement steel structure is split into two semi-circular steel clamps and two semi-circular steel sleeves.

[0007] Furthermore, in step 1, a semi-circular steel clamp is used to fix the upper part of the component to be reinforced, and the connection is achieved by bolts to achieve initial positioning; The semi-circular steel sleeve serves as the main structure and is spliced ​​together with the upper steel clamp through the kidney hole.

[0008] Furthermore, step 2 specifically includes: At the upper and lower ends of the semi-circular steel sleeve, the sealing strip rings are pre-embedded in the reserved grooves of the annular steel plate and the circumferential angle steel to form an integrated sealing assembly. Pre-set sealing strip grooves at the bolt connection points of the semi-circular steel sleeve splice, and simultaneously attach high-pressure resistant sealing strips during factory prefabrication.

[0009] Furthermore, in step 2, the annular steel plate and the circumferential angle steel are arranged in a circumferential manner with internal and external cooperation, that is, fixed along the edge areas of the top and bottom ports of the semi-circular steel sleeve to form a closed annular structure.

[0010] Furthermore, step 3 specifically includes: Standardization of annular space dimensions: Based on the flow properties of grouting materials and the stress requirements of components, the annular space dimensions are designed to be 6-10cm; for large-load components such as pile legs and jacket structures in offshore wind farms, the dimensions are adjusted to 19cm according to design requirements.

[0011] Furthermore, step 3 specifically includes: Standardization of grouting pressure control as a grouting parameter: Based on the grouting height h and the density ρ of the grouting material, the foundation pressure P is calculated according to the formula P=hρ, and is taken as 4-7MPa in combination with the actual project.

[0012] Furthermore, step 4 specifically includes: The process involves sequentially performing modular assembly, pre-sealing, overall fastening, and grouting reinforcement.

[0013] Furthermore, step 4 specifically includes: The grouting port connecting the grouting pump and the bottom of the steel sleeve is lubricated with pipe lubricant for the grouting pump and hose. Mix the grout according to the mixing ratio, and mix for 3-5 minutes.

[0014] Furthermore, step 4 specifically includes: Start the grouting pump and use a bottom-up grouting method. The initial pressure is controlled at 2-3 MPa. When the grout flows out from the top overflow port, gradually increase the pressure to 4-7 MPa and maintain the pressure for 10 minutes. During the grouting process, observe the pressure gauge changes. If the pressure drops suddenly, check for grout leakage. After troubleshooting, refill the grout to the overflow port to allow grout to flow out again.

[0015] Furthermore, step 4 specifically includes: After grouting is completed, cover the outside of the steel sleeve with a heat insulation and moisture retention layer. When the ambient temperature is ≥5℃, allow it to cure naturally for 3 days. When the temperature is <5℃, use electric heating to cure it to ensure the early strength development of the grout. After curing, ultrasonic testing was used to check the density of the grout in the annular space. At the same time, test blocks cured under the same conditions were made to test the compressive strength after 28 days.

[0016] The beneficial effects of the present invention are as follows, compared with the prior art: Improved construction efficiency: Modular components are prefabricated in the factory, reducing on-site assembly time to 1 / 3 of the traditional process. Taking the reinforcement of a single wharf pile foundation as an example, it only takes 4-6 hours from installation to grouting completion, saving 2-3 days compared to the on-site formwork process. Reduced safety risks: Each component weighs ≤50kg, eliminating the need for large hoisting equipment. When working in confined spaces, the operator's operating range is controllable, reducing safety risks such as falls from heights and equipment overturning by more than 60%. Stable reinforcement quality: The pre-installed sealing system and standardized grouting parameters ensure a grout density of ≥95%, and the compressive strength of the reinforced components increases by more than 13.6% (refer to the Ningbo wharf pile foundation reinforcement example, where the compressive strength reached more than 100MPa after 28 days). Strong adaptability to various scenarios: It can be used for various shapes of components such as columns and cuboids, and is suitable for different scenarios such as offshore wind farms, docks, and hydraulic structures. Since 2015, it has been safely applied in multiple offshore wind farm jacket reinforcement and dock pile foundation repair projects, extending the service life of the reinforced components by more than 20 years. Attached Figure Description

[0017] Figure 1 This is a flowchart of the assembly and construction process of the steel sleeve for structural reinforcement in this invention. Detailed Implementation

[0018] To make the objectives, technical solutions, and advantages of this invention clearer, the technical solutions of this invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments of this invention. The embodiments described in this application are merely some embodiments of this invention, and not all embodiments. Based on the spirit of this invention, other embodiments obtained by those skilled in the art without creative effort are all within the protection scope of this invention.

[0019] like Figure 1 As shown, an assembly and construction process for a steel sleeve used for structural reinforcement includes: The structural reinforcement steel sleeve assembly and construction process of this invention achieves efficient assembly and reliable reinforcement through modular disassembly of the steel structure, pre-installation of a sealing system, and standardized parameter design. Specifically, it includes the following: Step 1: Modular design of the steel sleeve for structural reinforcement; In a preferred but non-limiting embodiment of the present invention, in step 1, the structural reinforcement steel sleeve, which serves as the external reinforcement steel structure, is divided into two semi-circular steel clamps (upper fixing components) and two semi-circular steel sleeves (main load-bearing components). All the divided parts are prefabricated in the factory to ensure dimensional accuracy.

[0020] In a preferred but non-limiting embodiment of the present invention, in step 1, a semi-circular steel clamp is used to fix the upper part of the component to be reinforced, and the connection is achieved by bolts to achieve initial positioning; The semi-circular steel sleeve serves as the main structure and is spliced ​​together with the upper steel clamp through the waist hole. The waist hole design can accommodate component size deviations and facilitates on-site adjustment of the installation position.

[0021] Step 2: After modular design, design a pre-installed sealing system for the steel sleeve used for structural reinforcement; In a preferred but non-limiting embodiment of the present invention, step 2 specifically includes: Breaking away from traditional on-site sealing methods, it adopts a pre-assembled structure of "sealing strip ring + annular steel plate + circumferential angle steel": At the upper and lower ends of the semi-circular steel sleeve, the sealing strip rings are pre-embedded in the reserved grooves of the annular steel plate and the circumferential angle steel to form an integrated sealing assembly. Pre-set sealing strip grooves at the bolt connection points of the semi-circular steel sleeve splices. During factory prefabrication, high-pressure resistant sealing strips are simultaneously pasted to ensure that the high-pressure sealing strips fit tightly against the steel components after assembly, avoiding sealing failure caused by temporary on-site operations.

[0022] In the structural reinforcement steel sleeve system of the present invention, the annular steel plate and the circumferential angle steel serve as the core load-bearing structures of the sealing assembly, and are both located at the axial ends (i.e., the top and bottom) of the semi-circular steel sleeve, forming an integrated sealing unit together with the sealing strip ring. The specific positions and functions are adapted as follows: I. Core Setting Locations: Top and bottom end faces of the steel sleeve In a preferred but non-limiting embodiment of the present invention, in step 2, the annular steel plate and the circumferential angle steel are arranged in a circumferential manner with internal and external cooperation, that is, fixed along the edge areas of the top and bottom ports of the semi-circular steel sleeve to form a closed annular structure. Since the steel sleeve is assembled from two semi-circular units, the annular steel plate and the circumferential angle steel are also simultaneously disassembled into semi-circular prefabricated parts, which are welded and fixed to the individual semi-circular steel sleeves during factory processing, and automatically form a complete ring after on-site assembly.

[0023] From the perspective of functional division of labor, there is a clear matching relationship between their positions and roles: Circular angle steel (L-shaped section): mainly fixed to the inner edge of the end of the semi-circular steel sleeve (closer to the component to be reinforced). One right-angled side of the angle steel is welded to the inner wall of the steel sleeve, and the other right-angled side extends outward along the axial direction of the steel sleeve, forming the "inner retaining edge" of the sealing groove. This design utilizes the rigidity of the angle steel to support the sealing strip ring, preventing the sealing strip from deforming inward and failing under grouting pressure.

[0024] Annular steel plate (flat plate structure): Fixed to the outer edge of the semi-circular steel sleeve end (away from the component to be reinforced). Its outer diameter is the same as the outer diameter of the steel sleeve, and its inner diameter is slightly larger than the outer diameter of the circumferential angle steel, forming a 10-15mm wide pre-reserved groove with the extended edge of the circumferential angle steel. The planar structure of the annular steel plate ensures that the sealing strip ring fits smoothly against the end face of the steel sleeve, avoiding sealing gaps caused by uneven edges.

[0025] The pre-reserved groove formed by the two is perfectly matched to the cross-sectional size of the sealing strip ring (such as a 10×8mm EPDM sealing strip). It is fixed by spot welding to form an integrated structure of "steel sleeve end - circumferential angle steel - annular steel plate - sealing strip ring". It is pre-installed before leaving the factory and does not require secondary processing on site.

[0026] II. Technical Logic of Location Design: Adapting to Sealing Requirements and Construction Scenarios The placement of the annular steel plate and the circumferential angle steel is essentially designed to address the insufficient reliability of traditional on-site sealing. Its technical logic can be verified from three aspects: 1. Axial end seal: Blocks the core leakage path. The annular space between the steel sleeve and the component to be reinforced is the filling area for the grout. The top and bottom faces of the steel sleeve are the points of greatest risk for leakage due to concentrated grouting pressure—the top must withstand the static pressure of the rising grout, and the bottom must withstand the initial pressure impact from the grouting pump. Placing the sealing component at the end can directly prevent grout leakage along the gap between the steel sleeve end face and the component surface. This is consistent with the practical experience of "end sealing priority" in the grouting construction of the jacket structure at the Dongtai Wind Farm (which must withstand a maximum pressure of 7MPa).

[0027] 2. Factory pre-installed and adapted: Avoiding on-site operational errors. If the annular steel plate and circumferential angle steel are placed at the joint of the steel sleeve (rather than at the end), the alignment accuracy needs to be adjusted on-site, which can easily lead to misalignment of the sealing groove due to assembly gaps. However, if placed at the end, they can be positioned and welded in the factory using tooling fixtures, ensuring that the dimensional deviation of the reserved groove is ≤0.5mm. After the sealing strip ring is embedded, the fit is over 99%, which is far more reliable than temporary on-site pasting.

[0028] 3. Rigid support adaptation: resists the impact of grouting pressure. The inner fixing method of the circumferential angle steel can provide radial support for the sealing strip ring by utilizing the flexural strength of its L-shaped section; the outer fixing of the annular steel plate can balance the axial pressure of the grouting material. The "rigid frame" formed by the two can effectively resist the deformation under the grouting pressure of 4-7MPa, and prevent the sealing strip from being "crushed" or "squeezed out". This design directly matches the requirement in the reinforcement of wharf pile foundations that "the sealing structure must be compatible with high pressure and high humidity environment".

[0029] III. Connection with the steel sleeve: Factory prefabrication integrated The annular steel plate and the circumferential angle steel are not independent entities, but rather form an inseparable prefabricated unit with the steel sleeve. The specific connection method is as follows: During factory processing, the right-angled side of the semi-circular circumferential angle steel is welded to the inner wall of the end of the semi-circular steel sleeve, with a weld height of ≥6mm to ensure shear strength; Weld a semi-circular annular steel plate at the corresponding position to form a parallel gap (i.e., a reserved groove) with the extended edge of the circumferential angle steel. The groove width error is controlled within ±0.3mm. After the sealing strip ring is embedded into the reserved groove, 2-3 limiting points are fixed to the edge of the groove by spot welding (to prevent the sealing strip from falling off). When the steel sleeve is assembled on site, the limiting points are automatically aligned, and the sealing strip ring naturally forms a complete ring.

[0030] This "end pre-installation, rigid support, and factory integration" positioning design ultimately achieves synchronous installation and synchronous stress on the sealing structure and steel sleeve, effectively solving the core defects of "asynchronous sealing and assembly, and mismatch between pressure and support" in traditional processes.

[0031] Step 3: After designing the pre-installed sealing system, standardize the annular space and grouting parameters; In a preferred but non-limiting embodiment of the present invention, step 3 specifically includes: Standardized annular space dimensions: Based on the flow properties of grouting materials (mortar, fine aggregate concrete) and the stress requirements of components, the annular space dimensions are designed to be 6-10cm, which is suitable for conventional reinforcement scenarios; for large load components such as offshore wind farm pile legs and jacket structures, the dimensions can be adjusted to 19cm according to design requirements to ensure that the grouting material is fully filled without affecting the stress of the original components.

[0032] In a preferred but non-limiting embodiment of the present invention, step 3 further includes: Standardization of grouting pressure control as a grouting parameter: Based on the grouting height h and the density ρ of the grouting material, the foundation pressure P is calculated according to the formula P=hρ. Combined with the actual project, it is taken as 4-7MPa (corresponding to mortar density 2.3-2.5 tons / m³) to avoid excessive pressure causing deformation of the steel sleeve or expansion of cracks in the original component, while ensuring that the grout can fill the dead corner of the annular space.

[0033] Step 4: After standardizing the annular space and grouting parameters, optimize the construction process.

[0034] In a preferred but non-limiting embodiment of the present invention, step 4 specifically includes: The process of sequential modular assembly, pre-sealing, overall fastening and grouting reinforcement simplifies on-site operations and enables efficient construction in confined spaces and complex environments.

[0035] In a preferred but non-limiting embodiment of the present invention, step 4 further includes: The grouting port connecting the grouting pump and the bottom of the steel sleeve is lubricated with pipe lubricant (diluted grouting material of the same ratio) to ensure unobstructed pipeline flow. Mix the grout according to the mixing ratio (water-cement ratio 0.28) for 3-5 minutes. Test the grout flowability on site and ensure that the initial flowability is ≥290mm before use.

[0036] In a preferred but non-limiting embodiment of the present invention, step 4 further includes: Start the grouting pump and use a bottom-up grouting method. The initial pressure is controlled at 2-3 MPa. When the grout flows out from the top overflow port, gradually increase the pressure to 4-7 MPa (calculated according to the grouting height, such as 7 MPa for a 19m transition section). Maintain the pressure for 10 minutes. During the grouting process, observe the pressure gauge changes. If the pressure drops suddenly, check for grout leakage. After troubleshooting, refill the grout to the overflow port to allow grout to flow out again.

[0037] In a preferred but non-limiting embodiment of the present invention, step 4 further includes: After grouting is completed, cover the outside of the steel sleeve with a heat insulation and moisture retention layer. When the ambient temperature is ≥5℃, allow it to cure naturally for 3 days. When the temperature is <5℃, use electric heating to cure it to ensure the early strength development of the grout. After curing, ultrasonic testing was used to check the density of the annular space grout. At the same time, test blocks cured under the same conditions were made to test the compressive strength after 28 days, which must meet the design requirements (≥80MPa).

[0038] The technical innovation of this invention is as follows: After being disassembled, the weight of each individual steel component is reduced by more than 50%. No large hoisting equipment is required; only small lifting tools are needed for installation in confined spaces. This makes it suitable for complex scenarios such as dock pile foundations and jacket structures, while also reducing steel consumption and labor costs. The sealing rings are pre-assembled with the steel components in the factory, avoiding on-site operational errors and increasing the sealing success rate to over 98%, effectively preventing the risk of grout leakage and grout bursting. Define the range of values ​​for the annular space (6-10cm, 19cm in special scenarios) and the grouting pressure (4-7MPa), and verify this with engineering examples to ensure that the fluidity of the grouting material matches the structural load-bearing requirements. The steel clamp and the steel sleeve are connected by a hole in the waist, which can accommodate a dimensional deviation of ±5mm in the component to be reinforced, reducing the accuracy requirements for on-site installation and improving assembly efficiency.

[0039] An example of the present invention is as follows: (I) Construction Preparation Component prefabrication and testing: Two semi-circular steel clamps (material Q345, thickness 12mm) and two semi-circular steel sleeves (material Q345, thickness 12mm, inner diameter determined according to the diameter of the component to be reinforced, with a 6-10cm annular space reserved) are fabricated in the factory according to the design drawings. The size of the kidney hole is 35×25mm, and the bolts are 8.8 grade high-strength bolts. Pre-installed sealing assembly: The EPDM sealing strip ring (section size 10×8mm) is embedded into the reserved groove of the annular steel plate (thickness 10mm) and the circumferential angle steel (L50×5), and fixed by spot welding to form a sealing unit. Before leaving the factory, the sealing strip fit and groove matching are tested. Material preparation: Select ultra-early strength grout (such as UGO® SKG-3 type) to ensure that its initial flowability is ≥290mm, 30min flowability is ≥260mm, and 28-day compressive strength is ≥90MPa. At the same time, prepare grouting pump (main pump + standby pump, power 50kW), pipe lubricant, pressure gauge (range 0-10MPa) and other equipment.

[0040] On-site pretreatment: Clean the surface of the component to be reinforced: remove loose concrete, remove aquatic organisms and old anti-corrosion layer, seal cracks with epoxy, and ensure the surface of the component is flat. Mark the installation position: According to the design elevation, mark the installation control lines of the steel clamp and steel sleeve on the component to be reinforced to ensure that the coaxiality deviation of the upper and lower components is ≤3mm.

[0041] (II) Steel Sleeve Assembly Process Installation of upper steel clamps: Use small lifting tools (such as hand chain hoists) to hoist two semi-circular steel clamps (red characters 1 and 2) to the marked positions on the upper part of the component to be reinforced, so that the inner wall of the clamps fits against the surface of the component; Insert high-strength bolts (specification M20×100), tighten the bolts symmetrically, and control the torque to 300 N·m to ensure that the clamp is firmly fixed without loosening or displacement.

[0042] Main steel sleeve assembly: Hoist two semi-circular steel sleeves (red characters 3 and 4) so ​​that the kidney holes at the top of the sleeves are aligned with the bolt holes of the upper steel clamps. Insert bolts and fix them initially. Fine-tune the position of the sleeves through the kidney holes to ensure that the annular space is uniform (deviation ≤1mm). Tighten the bolts (M24×120) at the joint of the steel sleeve symmetrically from the middle to both ends, with the torque controlled at 450 N·m. At the same time, check the fit of the pre-installed sealing strip ring to ensure there are no warping edges or gaps.

[0043] Overall sealing inspection: Close the grouting port at the bottom of the steel sleeve, and introduce 0.2MPa compressed air from the top overflow port. Maintain the pressure for 5 minutes. If the pressure does not drop, the seal is considered qualified. If there is leakage, the bolt torque needs to be readjusted or the sealing ring needs to be replaced.

[0044] (III) Grouting Construction Process Grouting system commissioning: The grouting port connecting the grouting pump and the bottom of the steel sleeve is lubricated with pipe lubricant (diluted grouting material of the same ratio) to ensure unobstructed pipeline flow. Mix the grout according to the mixing ratio (water-cement ratio 0.28) for 3-5 minutes. Test the grout flowability on site and ensure that the initial flowability is ≥290mm before use.

[0045] Pressure grouting operation: Start the grouting pump and use a bottom-up grouting method. The initial pressure is controlled at 2-3 MPa. When the grout flows out from the top overflow port, gradually increase the pressure to 4-7 MPa (calculated according to the grouting height, such as 7 MPa for a 19m transition section). Maintain the pressure for 10 minutes. During the grouting process, observe the pressure gauge changes. If the pressure drops suddenly, check for grout leakage. After troubleshooting, refill the grout to the overflow port to allow grout to flow out again.

[0046] Maintenance and quality inspection: After grouting is completed, cover the outside of the steel sleeve with a heat insulation and moisture retention layer. When the ambient temperature is ≥5℃, allow it to cure naturally for 3 days. When the temperature is <5℃, use electric heating to cure it to ensure the early strength development of the grout. After curing, ultrasonic testing was used to check the density of the annular space grout. At the same time, test blocks cured under the same conditions were made to test the compressive strength after 28 days, which must meet the design requirements (≥80MPa).

[0047] (iv) Adaptation and adjustment for special scenarios In confined spaces (such as dock pile foundation groups): adopt a segmented hoisting method, first install the lower steel sleeve, then splice the upper steel clamp, and use a portable torque wrench to tighten the bolts to avoid large equipment occupying space; Offshore wind farm jacket: The size of the steel sleeve unit is controlled within the capacity of the transport ship. Divers work on the water platform to complete the underwater assembly and sealing test. Grouting is avoided in severe weather (work is stopped when the wind speed is >10m / s). For large-sized components (such as a 19m transition section): the annular space is designed to be 19cm, and high-flowability grouting material (flowability ≥280mm in 30min) is selected. Grouting is carried out in two stages (10m in the lower part + 9m in the upper part). After each grouting, the grout is shielded for 5 minutes to avoid excessive pressure during a single grouting.

[0048] IV. Verification of Technical Effects (I) Engineering Application Cases Dongtai Wind Farm Offshore Substation Jacket Reinforcement The process of this invention was applied to reinforce four annular spaces (110mm and 100mm in size) of the jacket structure of a 220kV offshore substation. The grouting height was 19m, and UGOTE® SKG-3 grouting material was used. In actual construction: Grouting of a single annular space takes about 5 hours, saving 3 hours compared to the traditional process. A total of 60m³ of grouting for 4 spaces was completed in just 4 work sessions. The maximum grouting pressure was controlled at 32MPa, and the equipment and pipelines were under full safety control with no grout leakage. The grouting solidified body has a 3-day compressive strength of 83.4 MPa, which exceeds the 28-day design strength (80 MPa), meeting the long-term load-bearing requirements of the jacket.

[0049] Piling foundation repair at a wharf in Ningbo The steel sleeves of this invention were used to reinforce 232 damaged pile foundations (crack width 0.42-2.49mm), with an annular space of 60mm and a grouting pressure of 5MPa. The entire pile foundation repair was completed within 6 months, saving 40% of the construction time compared to the traditional integral sleeve process; Tests showed that the bond strength between the grout and the steel sleeve was ≥6MPa. After hardening, the grout surface was smooth and free of air bubbles. The axial compressive bearing capacity of the pile foundation increased by 6.4%, and the flexural bearing capacity increased by 13.6%. No crack expansion has been observed to date.

[0050] (II) Summary of Core Advantages Economic benefits: Modular design reduces steel consumption by 15%-20%, and operations in confined spaces do not require large equipment, reducing labor costs by 30%; Reliability: The pre-installed sealing system and standardized parameter design increase the grouting qualification rate from 85% in traditional processes to over 98%; Adaptability: Compatible with columnar and cuboid components, suitable for complex scenarios such as marine, dock, and hydraulic engineering, solving the problem of "scenario limitation" in traditional processes; Durability: The reinforced components have improved corrosion resistance, extending their service life by more than 20 years in high-salt and tidal environments, thus reducing later maintenance costs.

[0051] The beneficial effects of the present invention are as follows, compared with the prior art: Improved construction efficiency: Modular components are prefabricated in the factory, reducing on-site assembly time to 1 / 3 of the traditional process. Taking the reinforcement of a single wharf pile foundation as an example, it only takes 4-6 hours from installation to grouting completion, saving 2-3 days compared to the on-site formwork process. Reduced safety risks: Each component weighs ≤50kg, eliminating the need for large hoisting equipment. When working in confined spaces, the operator's operating range is controllable, reducing safety risks such as falls from heights and equipment overturning by more than 60%. Stable reinforcement quality: The pre-installed sealing system and standardized grouting parameters ensure a grout density of ≥95%, and the compressive strength of the reinforced components increases by more than 13.6% (refer to the Ningbo wharf pile foundation reinforcement example, where the compressive strength reached more than 100MPa after 28 days). Strong adaptability to various scenarios: It can be used for various shapes of components such as columns and cuboids, and is suitable for different scenarios such as offshore wind farms, docks, and hydraulic structures. Since 2015, it has been safely applied in multiple offshore wind farm jacket reinforcement and dock pile foundation repair projects, extending the service life of the reinforced components by more than 20 years.

[0052] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and not to limit it. Although the present invention has been described in detail with reference to the above embodiments, those skilled in the art should understand that modifications or equivalent substitutions can still be made to the specific implementation of the present invention without departing from the spirit and scope of the present invention. Any modifications or equivalent substitutions should be covered within the scope of protection of the claims of the present invention.

Claims

1. An assembly and construction process for a steel sleeve for structural reinforcement, characterized in that, include: Step 1: Modular design of the steel sleeve for structural reinforcement; Step 2: After modular design, design a pre-installed sealing system for the steel sleeve used for structural reinforcement; Step 3: After designing the pre-installed sealing system, standardize the annular space and grouting parameters; Step 4: After standardizing the annular space and grouting parameters, optimize the construction process.

2. The assembly and construction process of the steel sleeve for structural reinforcement according to claim 1, characterized in that, In step 1, the steel sleeve used for structural reinforcement of the external steel structure is divided into two semi-circular steel clamps and two semi-circular steel sleeves. In step 1, a semi-circular steel clamp is used to fix the upper part of the component to be reinforced, and the connection is achieved by bolts to achieve initial positioning; The semi-circular steel sleeve serves as the main structure and is spliced ​​together with the upper steel clamp through the kidney hole.

3. The assembly and construction process of the steel sleeve for structural reinforcement according to claim 2, characterized in that, Step 2 specifically includes: At the upper and lower ends of the semi-circular steel sleeve, the sealing strip rings are pre-embedded in the reserved grooves of the annular steel plate and the circumferential angle steel to form an integrated sealing assembly. Pre-set sealing strip grooves at the bolt connection points of the semi-circular steel sleeve splice, and simultaneously attach high-pressure resistant sealing strips during factory prefabrication.

4. The assembly and construction process of the steel sleeve for structural reinforcement according to claim 3, characterized in that, In step 2, the annular steel plate and the circumferential angle steel are arranged in a circumferential manner with internal and external cooperation, that is, fixed along the edge areas of the top and bottom ports of the semi-circular steel sleeve to form a closed annular structure.

5. The assembly and construction process of the steel sleeve for structural reinforcement according to claim 4, characterized in that, Step 3 specifically includes: Standardization of annular space dimensions: Based on the flow properties of grouting materials and the stress requirements of components, the annular space dimensions are designed to be 6-10cm; for large-load components such as pile legs and jacket structures in offshore wind farms, the dimensions are adjusted to 19cm according to design requirements.

6. The assembly and construction process of the steel sleeve for structural reinforcement according to claim 5, characterized in that, Step 3 also includes: Standardization of grouting pressure control as a grouting parameter: Based on the grouting height h and the density ρ of the grouting material, the foundation pressure P is calculated according to the formula P=hρ, and is taken as 4-7MPa in combination with the actual project.

7. The assembly and construction process of the steel sleeve for structural reinforcement according to claim 6, characterized in that, Step 4 specifically includes: The process involves sequentially performing modular assembly, pre-sealing, overall fastening, and grouting reinforcement.

8. The assembly and construction process of the steel sleeve for structural reinforcement according to claim 7, characterized in that, Step 4 also includes: The grouting port connecting the grouting pump and the bottom of the steel sleeve is lubricated with pipe lubricant for the grouting pump and hose. Mix the grout according to the mixing ratio, and mix for 3-5 minutes.

9. The assembly and construction process of the steel sleeve for structural reinforcement according to claim 8, characterized in that, Step 4 also includes: Start the grouting pump and use a bottom-up grouting method. The initial pressure is controlled at 2-3 MPa. When the grout flows out from the top overflow port, gradually increase the pressure to 4-7 MPa and maintain the pressure for 10 minutes. During the grouting process, observe the pressure gauge changes. If the pressure drops suddenly, check for grout leakage. After troubleshooting, refill the grout to the overflow port to allow grout to flow out again.

10. The assembly and construction process of the steel sleeve for structural reinforcement according to claim 9, characterized in that, Step 4 also includes: After grouting is completed, cover the outside of the steel sleeve with a heat insulation and moisture retention layer. When the ambient temperature is ≥5℃, allow it to cure naturally for 3 days. When the temperature is <5℃, use electric heating to cure it to ensure the early strength development of the grout. After curing, ultrasonic testing was used to check the density of the grout in the annular space. At the same time, test blocks cured under the same conditions were made to test the compressive strength after 28 days.

Images