Integral pushing and translocating method for frame bridge

Abstract

The application discloses a kind of frame bridge integral pushing transverse moving method, including in the lateral pushing channel axis selected barrier-free area as frame bridge box prefabrication and transverse moving work site;Weak soil layer is replaced to lateral working pit, and slide plate and counterforce frame foundation are poured, four fluorine board is laid on the surface of slide plate and is coated with paraffin talcum powder mixture to form composite drag-reducing slip layer;Integral prefabrication frame bridge box;Anchor bar counterforce system is installed in counterforce frame foundation;Main top jack group lateral deviation correction jack group is arranged, and top iron, force transmission restraint crossbeam and attitude monitoring equipment are assembled;Pushing transverse moving is classified;Transverse alignment and attitude locking;Horizontal and vertical construction system conversion;Longitudinal jacking construction.The application greatly reduces land acquisition and demolition and pipeline relocation cost, and the disturbance to existing railway operation is very small, construction safety redundancy is high, quality stability is good, and is suitable for railway flat change vertical, urban tunnel bridge, dense building group and pipeline area limited site box type frame bridge jacking construction.

Description

Technical Field

[0001] This invention relates to the field of construction technology for municipal and railway underpass projects, and more specifically to a method for the overall jacking and lateral movement of a frame bridge, applicable to jacking construction projects for railway grade separation, urban underpasses, and box-frame structures passing under existing railway lines. Background Technology

[0002] A frame bridge is a type of bridge that uses a closed reinforced concrete frame structure. It is one of the core structural forms of grade separation projects where railways and highways intersect. A frame bridge is a box-shaped frame integrally cast from a top slab, side walls, and bottom slab. It is often used in grade separation scenarios where roads pass under existing railways, which can completely eliminate safety hazards at level crossings and improve traffic efficiency.

[0003] The frame bridge jacking method is currently the most mainstream and mature construction method for grade separation of existing railways and road underpasses of existing trunk lines. The traditional construction method involves setting up a working pit directly behind the tunnel axis, prefabricating the frame bridge box girder on-site, and then jacking it longitudinally under the railway subgrade along the axis after it reaches the required strength. This method is mature, has controllable disturbance, and produces good quality results, but it has extremely high requirements for the construction site, requiring a complete, open, and unobstructed prefabrication and jacking working surface behind the axis.

[0004] In urban built-up areas, densely populated residential areas along railway lines, and areas with dense pipeline corridors, buildings, high-voltage lines, dense water supply and drainage, and communication and power lines are commonly located directly behind the tunnel axis. These locations make demolition, land acquisition, and the placement of conventional longitudinal prefabricated working pits impossible, rendering traditional jacking techniques unfeasible. For such constrained sites, existing technologies have developed a few lateral movement construction solutions, but these generally suffer from numerous fundamental drawbacks:

[0005] 1. Most transverse shifting processes use prefabrication and splicing to shift the structure, resulting in multiple construction joints in the box body, which damages the overall rigidity and makes it prone to cracking, water seepage, structural deformation, and poor durability in the later stages. 2. Traditional sliding tracks have a simple structure, limited drag reduction measures, and uneven friction coefficients on the plate surface. During the sliding process, the box is prone to deviation, twisting, head-in, head-out and other posture defects, resulting in low positioning accuracy and a large amount of rework. 3. The reaction system generally adopts a large-volume gravity-type concrete backing, which results in a large amount of temporary engineering work, high material consumption, non-reusability, long construction period, and poor economic efficiency. 4. The correction method is crude, relying on workers' experience for fine-tuning, without graded thresholds or quantitative control standards. Forcibly pushing when the deviation is too large can easily cause structural damage to the box. 5. The jacking force transmission system has no constrained structure, and the free length of the jacking iron is too large over long distances, resulting in extremely high risks of buckling and collapse, and prominent safety hazards; 6. All construction relies on experience, there is no complete calculation system, there is no quantitative calculation basis for jacking force, foundation, anti-sliding and back resistance, safety redundancy is uncontrollable, and it cannot meet the high-level management and control requirements of existing railway lines.

[0006] Therefore, there is an urgent need to provide a construction method for the overall jacking and lateral movement of frame bridges that is adaptable to restricted sites, has strong integrity, high precision, and is safe and controllable. Summary of the Invention

[0007] In view of this, the present invention provides a method for the overall jacking and lateral movement of a frame bridge, which aims to overcome the defects of existing technologies such as poor adaptability to limited sites, poor structural integrity, low positioning accuracy, high safety risks, and lack of systematic verification support, so as to achieve overall prefabrication, smooth lateral movement, precise alignment, and safe jacking of large-tonnage box girder in confined spaces.

[0008] To achieve the above objectives, the present invention adopts the following technical solution: A method for integral jacking and lateral displacement of a frame bridge includes the following steps: S1. Construction preparation and surveying: Select an unobstructed area on the side of the jacking channel axis as the work site for the prefabrication and lateral movement of the frame bridge box body, establish an independent plane and elevation measurement control network, and lay out the outline of the working pit, the edge line of the sliding slide, the foundation of the reaction frame, and the location of the jacking equipment. S2. Foundation treatment of working pit and construction of sliding track: Replace the weak soil layer of the lateral working pit, pour an integrated rigid sliding plate and reaction frame foundation, lay PTFE plate on the surface of the sliding plate and coat it with paraffin and talc powder mixture to form a composite drag-reducing sliding layer, and cast-in-place guide and limiting piers on both sides of the sliding plate to form a double-sided constrained sliding track. S3. Precast Frame Bridge: The frame bridge box body is precast as a whole on the sliding plate and cured until the concrete strength and elastic modulus reach 100% of the design strength. S4. Installation of reaction system and jacking system: Install the anchor bar reaction system in the reaction frame foundation; arrange the main jacking jack group and hydraulic pump station symmetrically on the rear side of the box bottom plate, arrange the lateral correction jack group on both sides of the box, and assemble the jacking iron, force transmission constraint beam and attitude monitoring equipment. S5. Staged jacking and lateral movement: The staged jacking mode with a constant small stroke of 20-30cm is adopted to control the displacement deviation of each jack to ≤±3mm; after each jacking stroke is completed, the pick is immediately returned and the jacking iron is added to achieve uniform lateral movement of the entire box. S6. Lateral alignment and attitude locking: After the box body slides to the longitudinal jacking design axis position, the axis, elevation, and plane torsion parameters are checked. After confirming that the positioning accuracy meets the requirements, the attitude of the box body is temporarily locked by a temporary limiting structure. S7. Transverse and longitudinal construction system conversion: Remove all transverse jacking jacks, jacking irons, correction equipment and temporary limiting structures, construct the longitudinal jacking system, and complete the conversion from the transverse sliding system to the longitudinal underpass jacking system; S8. Longitudinal jacking construction: During the railway operation window, the box girder is jacked under the roadbed using a balanced construction process of excavation and jacking.

[0009] Preferably, in step S2, the foundation replacement of the working pit adopts B-graded crushed stone layered backfilling, with a layer backfill thickness ≤20cm, a layer compaction degree ≥96%, and the modified allowable bearing capacity of the foundation after replacement is not less than 220kPa; the overall flatness of the sliding plate is ≤2mm / 2m.

[0010] Preferably, in step S2, the operating friction coefficient of the composite drag-reducing sliding layer is in the range of 0.08 to 0.15, and the static friction coefficient of the housing at startup is 1.3 to 1.5 times the operating friction coefficient.

[0011] Preferably, in step S4, the anchor bar reaction system consists of pre-embedded precision-rolled threaded steel anchor bars in the reaction frame foundation, and steel distribution beams are assembled on the anchor bars, with a tensile safety factor of ≥1.5 for the anchor bars.

[0012] Preferably, in step S4, the working load efficiency of the jack is controlled at 0.7 to 0.8, and the safety reserve coefficient is ≥1.2.

[0013] Preferably, in step S5, the length of the free section of the top iron is ≤1.5m, and steel constraint beams are added at preset intervals in the ultra-long force transmission section to restrict the lateral displacement of the top iron in all directions.

[0014] Preferably, before performing graded jacking and lateral movement, graded trial jacking and working condition verification are required: apply jacking force to the box body using a graded low-speed pressurization method to cause the box body to slide slightly by 5-10mm, hold the pressure and stand still for more than 30 minutes, and check the deformation of the reaction frame, the integrity of the slide rail, the structural condition of the box body, the sealing of the hydraulic system and the synchronization accuracy of the jacks. Only after confirming that the system working condition is stable can the graded jacking process be carried out.

[0015] Preferably, attitude correction is performed during the graded jacking and lateral movement process: the lateral movement process monitors the offset of the box axis, elevation change, structural torsion and differential settlement of the sliding plate, and adopts a graded correction strategy according to the offset: small deviation hydraulic pressure unequal pressure fine adjustment, medium deviation lateral jack torque correction, large deviation static correction by stopping the jacking, and strict control of the box sliding attitude throughout the process.

[0016] Preferred, graded correction strategies include: when the shaft offset of the box body is ≤5mm, dynamic fine-tuning correction is performed using hydraulic pressure unequal on both sides of the jacks; when the shaft offset is 5mm to 10mm, lateral correction jacks are activated in conjunction with guide limit blocks to apply reverse correction torque; when the shaft offset is >10mm, the jacking is stopped immediately, static wedge block correction is used, and work can only resume after checking for uneven friction.

[0017] Preferably, safety calculations must be performed during the jacking and lateral movement process, including: The lateral movement jacking force Fh = μG, the starting jacking force Fq = (1.3~1.5)μG; the foundation bearing capacity σ = G / As ≤ [σ]; the sliding plate anti-slip safety factor Ks ≥ 1.3; the back anchor bar tensile safety factor ≥ 1.5; the jacking iron pressure bar stability calculation; the correction torque Mc ≥ the box body deflection torque M.

[0018] As can be seen from the above technical solution, compared with the prior art, the present invention discloses a method for the overall jacking and lateral movement of a frame bridge, which completely eliminates the dependence on the site behind the channel axis. All prefabrication, sliding, and positioning operations can be completed using only the lateral idle site, greatly reducing the amount of land acquisition, demolition, building demolition, and pipeline relocation work. It is particularly suitable for densely populated and restricted urban conditions. The box body is cast in one piece without segmentation, cold joints, or splicing. Its overall rigidity, crack resistance, and waterproofing are far superior to the split prefabrication and splicing process, and the structural durability is significantly improved. By adopting synchronous jacking, three-level graded correction, and closed-loop control of sliding plate settlement, millimeter-level precise alignment can be achieved, completely solving the stubborn problems of box body torsion, deviation, head-up, and head-up. It abandons the traditional large-volume temporary concrete backing and adopts a prefabricated modular reaction system, which can be reused multiple times, greatly reducing the amount of concrete used in temporary projects and construction waste. A unique, comprehensive calculation system for lateral movement is developed, enabling calculation, traceability, and approval for all aspects, including jacking force, foundation, anti-slip, backfill, jacking, and correction. This system breaks away from traditional experience-based construction and meets the high safety standards of national railways. The entire lateral movement process involves pure sliding, without excavation or disturbance to the roadbed. Only longitudinal jacking is carried out during maintenance windows, maximizing railway operational safety. Lateral prefabrication can be integrated with preliminary protection and foundation pit construction. Modular equipment is easy to assemble and disassemble, significantly shortening the overall construction period compared to traditional relocation schemes. Attached Figure Description

[0019] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on the provided drawings without creative effort.

[0020] Figure 1 The construction method flowchart provided by the present invention; Figure 2 This is a schematic diagram of the working pit layout provided by the present invention.

[0021] Among them, 1-top pushing channel; 2-working pit; 3-box body 3; Detailed Implementation The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0022] In existing frame bridge jacking construction, a working pit 2 is set up directly behind the channel axis, and the frame bridge box body 3 is prefabricated on-site. After the strength meets the standard, it is directly jacked longitudinally under the railway subgrade along the axis. This places extremely high demands on the construction site, requiring a complete, open, and unobstructed prefabrication and jacking working surface behind the axis. However, under site-constrained construction conditions, it is impossible to guarantee the smooth progress of the jacking operation, and the construction cost is high. In view of this, this invention discloses a method for the overall jacking and lateral movement of a frame bridge. The complete frame bridge box body 3 is constructed by lateral displacement integral cast-in-place prefabrication, and a uniform low-resistance sliding track is constructed using a rigid sliding plate and a PTFE plate paraffin talc powder composite drag reduction system; a method is adopted to install... The system features a modular, reusable reaction force system with prefabricated threaded steel anchor bars and steel distribution beams; combined with multi-point intelligent synchronous hydraulic graded jacking technology, jacking iron constraint anti-instability structure, and three-level threshold dynamic correction strategy, it achieves precise positioning of the box girder through pure lateral sliding; through the conversion of the transverse and longitudinal systems, it utilizes railway skylights to complete longitudinal jacking and tunneling; and is equipped with a unique complete set of construction quantitative calculation systems to achieve controllable parameters, safety, and quality throughout the entire process. It can significantly reduce the costs of land acquisition, demolition, and pipeline relocation, with minimal disturbance to existing railway operations, high construction safety redundancy, and good quality stability. It is suitable for the jacking construction of box girder bridges in railway grade separation projects, urban underpasses, dense building complexes, and pipeline-restricted sites.

[0023] A method for integral jacking and lateral displacement of a frame bridge according to an embodiment of the present invention includes the following steps: S1. Construction preparation and surveying: Investigate the distribution of pipelines, structures and existing lines on site, select an unobstructed area on the side of the jacking channel 1 axis as the prefabrication and lateral movement work site for the frame bridge box 3, establish an independent plane and elevation measurement control network, and accurately lay out the outline of the working pit 2, the sliding slide edge line, the reaction frame foundation and the jacking equipment layout points. S2. Foundation Treatment and Sliding Track Construction of Working Pit 2: The weak soil layer of the lateral working pit 2 will be completely replaced. Graded crushed stone will be used for layered compaction. Group B graded crushed stone will be used for backfilling. The thickness of each layer will be ≤20cm, and the compaction degree of each layer will be ≥96%. The allowable bearing capacity of the foundation after replacement will not be less than 220kPa. The overall flatness of the sliding plate will be ≤2mm / 2m. The sliding plate surface will be equipped with a bow slope and a two-way drainage slope. After the replacement is completed, a reinforced concrete rigid sliding plate and an integrated reaction frame foundation will be integrally cast in the working pit 2. The flatness and elevation accuracy of the sliding plate surface will be strictly controlled. The surface of the sliding plate will be covered with PTFE plate and coated with a mixture of paraffin wax and talc powder to form a composite drag-reducing sliding layer. Cast-in-place concrete guide and limiting piers on both sides of the sliding plate will form a double-sided constrained sliding track. The operating friction coefficient of the composite drag-reducing sliding layer will be in the range of 0.08 to 0.15. The static friction coefficient of the box 3 at startup will be 1.3 to 1.5 times the operating friction coefficient. S3. Precast frame bridge: The bottom plate, side walls and top plate of the frame bridge are tied together in one go in the precast area of ​​the lateral sliding plate. The jacking force embedded parts, attitude monitoring points and correction connection components are pre-embedded. The formwork is erected as a whole and the concrete is poured continuously in one go. There are no cold joints in the construction of the structure. The concrete is kept warm and moist until the concrete strength and elastic modulus reach 100% of the design strength. S4. Installation of the reaction system and jacking system: Pre-embed precision-rolled threaded steel anchor bars in the reaction frame foundation. The tensile safety factor of the anchor bars is ≥1.5. Assemble an integral steel distribution beam on the anchor bars to form a modular anchor bar reaction system. The anchor bar reaction system does not require a large volume of concrete gravity backing and can be reused across projects after disassembly and assembly. Large-tonnage hydraulic main jacking jacks and intelligent synchronous hydraulic pump stations are symmetrically arranged on the rear side of the frame bridge bottom plate. Lateral correction jacks are arranged on both sides of box 3. Jacks, force transmission constraint beams and full-process attitude monitoring equipment are installed. The total effective output force of the jacks (main jacking jacks and lateral correction jacks) is selected according to the most unfavorable starting jacking force of box 3. The working load efficiency of the jacks is controlled at 0.7~0.8. The overall equipment safety reserve factor is ≥1.2. Full-load overpressure operation is prohibited. S5. Staged jacking test and working condition verification: Apply jacking force to box 3 using a staged low-speed pressurization method to make box 3 slip slightly by 5-10mm. Hold the pressure and stand still for more than 30 minutes. Check the deformation of the reaction frame, the integrity of the slide, the structural condition of box 3, the sealing of the hydraulic system and the synchronization accuracy of the jack. Only after confirming that the system working condition is stable can the staged jacking process be entered. S6. Staged jacking and lateral movement: A staged jacking mode with a constant small stroke of 20-30cm is adopted. The pressure and displacement of each jack are controlled by a closed-loop intelligent synchronous pump station to control the displacement deviation between multiple jacks to ≤±3mm. After each jacking stroke is completed, the pick is immediately returned and the jacking iron is added. The free section length of the jacking iron is ≤1.5m. Steel constraint beams are added at preset intervals in the ultra-long force transmission section to restrict the lateral displacement of the jacking iron in all directions and eliminate the safety risks of buckling, collapse, and instability of the jacking iron. In the long force transmission section, an intermediate lateral constraint beam is added to suppress the buckling and instability of the jacking iron pressure bar, so as to achieve uniform and pure sliding lateral movement of the box body 3 as a whole. The lateral movement stage of box body 3 adopts a pure sliding construction mode without any earthwork excavation, ensuring the integrity of the sliding track and the uniform resistance of the plate surface, and ensuring the smooth and uniform displacement of box body 3. S7. Attitude Correction: During the lateral movement process, monitor the axis offset, elevation change, structural torsion and differential settlement of the sliding plate of box 3. According to the offset, adopt a graded correction strategy: small deviation hydraulic pressure unequal pressure fine adjustment, medium deviation lateral jack torque correction, and large deviation static correction by stopping the jack. Strictly control the sliding attitude of box 3 throughout the process. During the entire lateral movement process, the differential settlement of the sliding plate should be ≤2mm / m, and the total settlement of the sliding plate should be ≤10mm. If the settlement data exceeds the standard, work should be stopped immediately to avoid the risk of tilting, twisting, and structural cracking of the box body. The graded correction strategy includes: when the axis deviation of the box body is ≤5mm, dynamic fine-tuning correction is carried out by using double-sided jacks with unequal hydraulic pressure; when the axis deviation is 5mm to 10mm, lateral correction jacks are activated in conjunction with guide limit blocks to apply reverse correction torque; when the axis deviation is >10mm, the jacking is stopped immediately, static wedge block correction is used, and work can only resume after checking for uneven friction. S8. Lateral alignment and attitude locking: After the box body 3 slides to the longitudinal jacking design axis position, the axis, elevation, and plane torsion parameters are checked multiple times. After confirming that the positioning accuracy meets the design and specification requirements, the attitude of the box body 3 is temporarily locked through a temporary limiting structure. S9. Transverse and longitudinal construction system conversion: Remove all transverse jacking jacks, jacking irons, correction equipment and temporary limiting structures, construct longitudinal jacking cutting edge, back foundation and soil removal system, and complete the overall conversion from transverse sliding system to longitudinal underpass jacking system. S10. Longitudinal jacking construction: Utilizing the existing railway operation window, the box girder 3 will be jacked under the roadbed using a balanced construction process of excavation and jacking. After positioning, gap grouting and sealing, waterproofing layer construction, approach retaining walls and drainage system ancillary works will be carried out. All temporary structures will be demolished and the site and existing line conditions will be restored.

[0024] In this embodiment, a complete set of quantitative safety verification systems is provided for the entire construction process, including: The lateral movement jacking force Fh = μG, and the starting jacking force Fq = (1.3~1.5)μG, where G is the self-weight of the frame bridge box 3, and μ is the running friction coefficient; the foundation bearing capacity σ = G / As ≤ [σ]; the sliding plate anti-slip safety factor Ks ≥ 1.3; the back anchor bar tensile safety factor ≥ 1.5; the jacking iron pressure bar stability calculation; the correction moment Mc ≥ the box 3 deflection moment M; all construction parameters are quantifiable, controllable, calculable, and traceable.

[0025] Example 1 This embodiment describes a grade separation project for an existing conventional railway, requiring the construction of a new single-span reinforced concrete frame bridge to pass under the operating railway. The area directly behind the tunnel axis is adjacent to residential areas, municipal water supply and drainage systems, and a cluster of communication and power lines. There are no available prefabricated working pits, making traditional longitudinal jacking techniques unsuitable. However, the tunnel has regular open space to the side, allowing the construction method of this invention to be used.

[0026] The external dimensions of box girder 3 are: length 24.0m × width 14.6m × height 7.2m. The concrete strength grade is C40, and the total self-weight of box girder 3 is G = 62400kN. The surface layer of the site is miscellaneous fill, and the underlying layer is silty clay. After replacement with graded crushed stone, the allowable bearing capacity of the foundation is [σ] = 220kPa. The sliding system adopts a composite drag-reducing structure of PTFE plate and paraffin talc powder. The measured operating friction coefficient μ = 0.12, and the starting friction coefficient is taken as 1.4 times the operating friction coefficient.

[0027] First, construction preparation and surveying and setting out are carried out, the pipelines and structures on site are checked, the lateral construction area is selected, an independent surveying and control network is established, and the foundation pit, slide, backfill, and equipment locations are accurately set out.

[0028] Foundation treatment and slide construction were carried out, soft and miscellaneous fill was removed, and B-graded crushed stone was used for backfilling and compaction in layers with a layer thickness ≤20cm and a compaction degree ≥96%. A rigid reinforced concrete slide and an integrated back base were cast as a whole, with a slide flatness ≤2mm / 2m. A bow slope and two-way drainage were set up, and the slide surface was covered with PTFE sheet and a paraffin talc powder drag-reducing layer. Guide and limiting piers were cast on both sides to form a restraint track.

[0029] In the lateral sliding plate area, the entire cast-in-place frame bridge is completed in one go, including steel reinforcement binding, embedded part placement, overall formwork, and continuous pouring, with no construction cold joints, and cured to 100% of the design value of strength and modulus of elasticity.

[0030] The system is equipped with a modular reaction force system and a synchronous jacking system. The jacking reaction force is borne by precision-rolled threaded steel anchor bars and steel distribution beams, with a tensile safety factor of 1.58. Eight 2000kN main jacks are symmetrically arranged with a load factor of 0.75. The total effective output meets the requirements for starting the jacking and sufficient safety reserves are reserved. Lateral correction jacks, jacking iron constraint beams and monitoring equipment are also installed.

[0031] A graded trial top operation was carried out. The pressure was increased at a low speed to make the box body 3 slip slightly by 5-10mm. The pressure was held for 30 minutes to observe the stability of the system. After confirming that the backrest, slide rail, box body 3 and hydraulic system were all normal, the formal lateral movement began.

[0032] The formal lateral movement adopts a single 20-30cm small stroke staged synchronous jacking, and the displacement difference of the multi-cylinder is controlled to be ≤±3mm. A constraint beam is added to the long jacking section to prevent the jacking iron from becoming unstable. The entire lateral movement is a pure sliding movement without digging, which ensures uniform resistance of the sliding track.

[0033] Strict three-level correction control is implemented: minor deviations are fine-tuned using unequal hydraulic pressure; deviations of 5-10mm are corrected using lateral jack torque; deviations exceeding 10mm are immediately stopped for static correction. Throughout the process, the differential settlement of the sliding plate is controlled to ≤2mm / m, and the total settlement to ≤10mm. In this embodiment, the maximum instantaneous deviation is 4mm, and the final positioning axis deviation is 3mm and the elevation deviation is 2mm, achieving millimeter-level precise alignment.

[0034] After locking box 3, the transverse and longitudinal systems were converted, the transverse jacking equipment was dismantled, and the longitudinal cutting edge, backing, and excavation system were constructed. The longitudinal excavation and jacking were carried out during railway nighttime maintenance windows to smoothly pass under the railway subgrade.

[0035] After the structure is in place, gap grouting, waterproofing, access roads and ancillary works will be carried out, temporary structures will be dismantled, and the site will be restored to its original state.

[0036] Quantitative verification results: The operating jacking force Fh = 7488kN, and the starting jacking force Fq = 10483kN; the effective output of the jack is 12000kN, which meets the equipment selection requirements; the foundation bearing capacity, the anti-slip safety factor of the sliding plate, the tensile safety factor of the anchor bar, the stability of the jacking iron, and the correction torque all meet the specifications and control standards of this invention.

[0037] This embodiment successfully solved the technical problem of limited rear space preventing conventional jacking. The box body 3 remained intact without cracks or deformation, and its positioning accuracy was far superior to traditional processes. The consumption of temporary engineering materials was greatly reduced, the construction period was shortened by more than 25%, and there was no adverse impact on the operation of existing railways. Safety, quality, and efficiency were all improved.

[0038] The various embodiments in this specification are described in a progressive manner, with each embodiment focusing on its differences from other embodiments. Similar or identical parts between embodiments can be referred to interchangeably. For the apparatus disclosed in the embodiments, since they correspond to the methods disclosed in the embodiments, the description is relatively simple; relevant parts can be referred to the method section.

[0039] The above description of the disclosed embodiments enables those skilled in the art to make or use the invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the invention. Therefore, the invention is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A method for integral jacking and lateral displacement of a frame bridge, characterized in that, Includes the following steps: S1. Construction preparation and surveying: Select an unobstructed area on the side of the jacking channel axis as the work site for the prefabrication and lateral movement of the frame bridge box body, establish an independent plane and elevation measurement control network, and lay out the outline of the working pit, the edge line of the sliding slide, the foundation of the reaction frame, and the location of the jacking equipment. S2. Foundation treatment of working pit and construction of sliding track: Replace the weak soil layer of the lateral working pit, pour an integrated rigid sliding plate and reaction frame foundation, lay PTFE plate on the surface of the sliding plate and coat it with paraffin and talc powder mixture to form a composite drag-reducing sliding layer, and cast-in-place guide and limiting piers on both sides of the sliding plate to form a double-sided constrained sliding track. S3. Precast Frame Bridge: The frame bridge box body is precast as a whole on the sliding plate and cured until the concrete strength and elastic modulus reach 100% of the design strength. S4. Installation of reaction system and jacking system: Install the anchor bar reaction system in the reaction frame foundation; arrange the main jacking jack group and hydraulic pump station symmetrically on the rear side of the box bottom plate, arrange the lateral correction jack group on both sides of the box, and assemble the jacking iron, force transmission constraint beam and attitude monitoring equipment. S5. Staged jacking and lateral movement: The staged jacking mode with a constant small stroke of 20-30cm is adopted to control the displacement deviation of each jack to ≤±3mm; after each jacking stroke is completed, the pick is immediately returned and the jacking iron is added to achieve uniform lateral movement of the entire box. S6. Lateral alignment and attitude locking: After the box body slides to the longitudinal jacking design axis position, the axis, elevation, and plane torsion parameters are checked. After confirming that the positioning accuracy meets the requirements, the attitude of the box body is temporarily locked by a temporary limiting structure. S7. Transverse and longitudinal construction system conversion: Remove all transverse jacking jacks, jacking irons, correction equipment and temporary limiting structures, construct the longitudinal jacking system, and complete the conversion from the transverse sliding system to the longitudinal underpass jacking system; S8. Longitudinal jacking construction: During the railway operation window, the box girder is jacked under the roadbed using a balanced construction process of excavation and jacking.

2. The method for integral jacking and lateral movement of a frame bridge according to claim 1, characterized in that, In step S2, the foundation replacement of the working pit adopts B-graded crushed stone layered backfilling, with a layer backfill thickness ≤20cm, a layer compaction degree ≥96%, and the modified allowable bearing capacity of the foundation after replacement is not less than 220kPa; the overall flatness of the sliding plate is ≤2mm / 2m.

3. The method for integral jacking and lateral movement of a frame bridge according to claim 2, characterized in that, In step S2, the operating friction coefficient of the composite drag-reducing sliding layer is in the range of 0.08 to 0.15, and the static friction coefficient of the box body at startup is 1.3 to 1.5 times the operating friction coefficient.

4. The method for integral jacking and lateral movement of a frame bridge according to claim 1, characterized in that, In step S4, the anchor bar reaction system consists of pre-embedded precision-rolled threaded steel anchor bars in the reaction frame foundation, and steel distribution beams are assembled on the anchor bars. The tensile safety factor of the anchor bars is ≥1.

5.

5. The method for integral jacking and lateral movement of a frame bridge according to claim 4, characterized in that, In step S4, the working load efficiency of the jack is controlled between 0.7 and 0.8, and the safety reserve factor is ≥1.

2.

6. The method for integral jacking and lateral movement of a frame bridge according to claim 1, characterized in that, In step S5, the length of the free section of the top iron is ≤1.5m, and steel constraint beams are added at preset intervals in the ultra-long force transmission section to restrict the lateral displacement of the top iron in all directions.

7. A method for integral jacking and lateral displacement of a frame bridge according to any one of claims 1 to 6, characterized in that, Before performing the graded jacking and lateral movement, a graded test jacking and working condition verification must be carried out: apply jacking force to the box body using a graded low-speed pressurization method to make the box body slide slightly by 5-10mm, hold the pressure and stand still for more than 30 minutes, and check the deformation of the reaction frame, the integrity of the slide rail, the structural condition of the box body, the sealing of the hydraulic system and the synchronization accuracy of the jacks. Only after confirming that the system working condition is stable can the graded jacking process be carried out.

8. The method for integral jacking and lateral displacement of a frame bridge according to claim 7, characterized in that, During the graded jacking and lateral movement, attitude correction is carried out: the lateral movement process monitors the offset of the box axis, elevation change, structural torsion and differential settlement of the sliding plate, and adopts a graded correction strategy according to the offset: small deviation hydraulic pressure unequal pressure fine adjustment, medium deviation lateral jack torque correction, and large deviation static correction by stopping the jacking, and strictly controlling the sliding attitude of the box throughout the process.

9. The method for integral jacking and lateral displacement of a frame bridge according to claim 8, characterized in that, The graded correction strategy includes: when the shaft offset of the box body is ≤5mm, dynamic fine-tuning correction is performed by using double-sided jacks with unequal hydraulic pressure; when the shaft offset is 5mm to 10mm, lateral correction jacks are activated in conjunction with guide limit blocks to apply reverse correction torque; when the shaft offset is >10mm, the jacking is stopped immediately, static wedge blocks are used for correction, and work can only resume after checking for uneven friction.

10. A method for integral jacking and lateral movement of a frame bridge according to claim 9, characterized in that, Safety calculations must be performed during the jacking and lateral movement process, including: The lateral movement jacking force Fh = μG, the starting jacking force Fq = (1.3~1.5)μG; the foundation bearing capacity σ = G / As ≤ [σ]; the sliding plate anti-slip safety factor Ks ≥ 1.3; the back anchor bar tensile safety factor ≥ 1.5; the jacking iron pressure bar stability calculation; the correction torque Mc ≥ the box body deflection torque M.

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