CN110700117A

CN110700117A - Integral synchronous jacking transformation method for overpass

Info

Publication number: CN110700117A
Application number: CN201910811788.7A
Authority: CN
Inventors: 李树敬
Original assignee: Fourth Engineering Co Ltd of China Railway 14th Bureau Co Ltd
Current assignee: Fourth Engineering Co Ltd of China Railway 14th Bureau Co Ltd
Priority date: 2019-08-30
Filing date: 2019-08-30
Publication date: 2020-01-17

Abstract

The invention provides an integral synchronous jacking transformation method for an overpass, which realizes the continuous operation of jack alternate jacking so as to be safe and controllable. The alternate jacking is adopted in the jacking process, the beam body is in a state that two groups of jacks alternately support the beam body, when the two groups of jacks alternately support the beam body, the displacement of the beam body is in a controllable state, and under the supporting state of each group, the compression amount of the supporting system hardly changes, so that the internal force of the beam body hardly changes. Under the operation mode, the displacement of the beam body is continuously in a controlled state from the beginning to the end of jacking. The pressure of each jack is continuously monitored, so that the beam body can be prevented from being damaged in the jacking process, and the whole bridge jacking system is also in a safe and controllable state. The invention is suitable for series of projects which have insufficient clearance under the existing overpass and need to be subjected to integral lifting construction under the condition of traffic, navigation or other conditions.

Description

Integral synchronous jacking transformation method for overpass

Technical Field

The invention relates to the technical field of bridge construction, in particular to an integral synchronous jacking transformation method for an overpass.

Background

Along with the development of the railway construction industry, a plurality of existing railways can not meet the current operation requirements and need electrified transformation, the problems that the original clear height of a highway iron overpass can not meet the minimum clear height requirement of the erection of an electrified contact net and the like can occur in the electrified transformation process, and if the construction method is according to the common traditional construction method: and (4) protecting the overhead railway → dismantling the existing bridge → building in situ in the protection process. For the existing business line railway, due to the limitation of site conditions and the need of ensuring the normal operation of the existing business line railway, the method ensures that the construction period is longer in the dismantling and building processes, and the construction cost is higher. Due to the long construction period, the railway travelling crane brings large safety risk and protection pressure. And some construction processes are limited by construction places, so that construction cannot be carried out on the existing business line railway line, and the development of the railway construction industry is influenced.

Disclosure of Invention

In order to overcome the defects in the prior art, the invention provides an integral synchronous jacking transformation method for an overpass, which comprises the following steps: firstly, construction preparation;

constructing a pier foundation;

thirdly, constructing a support bracket system;

fourthly, constructing a limiting system;

fifthly, jacking construction;

sixthly, pier reconstruction construction;

and seventhly, dismantling the equipment and chiseling off the column-holding beam.

Further, the first step further comprises:

the expansion joints at bridge abutments at two ends of the railway overpass need to be chiseled off, the rest expansion joints and beam joints on the bridge deck are not processed, the steel pipe piles are adopted to set hard isolation protection at the positions 2m to 3m away from the existing line within the construction range of 20m to 30m at two sides of the existing line, the steel pipe piles are 2m to 3m long and are buried underground for 0.5m to 1 m.

Further, the second step further comprises:

(1) excavating foundation earthwork of the bridge pier;

the jacking support system counter-force foundation is arranged on the lower embracing column beam, after jacking is completed, the lower embracing column beam is buried under the ground to be used as a permanent structure, earthwork at the plane position of the lower embracing column beam is removed, the abutment is excavated to form a conical slope, the earthwork at the part of the abutment enlarged foundation is removed, and steel supports are convenient to install;

(2) roughening the surfaces of the pier column and the abutment foundation;

the method comprises the following steps of (1) chiseling original concrete at a preset position of a pier stud and within a bridge abutment foundation cushion cap range by using a steel chisel, wherein the surface layer of the original concrete needs to be chiseled during chiseling, and the chiseling concave-convex difference is not less than 6 mm;

(3) anchoring the support anchor;

the jacking counter-force support is arranged on the column embracing beam, an anchoring part of a punching and anchor bolt is adopted, and then a steel plate with the same size as a steel barrel supporting flange plate is adopted to accurately position the anchoring part; after the anchoring piece is constructed, mortar leveling treatment is carried out on the top surface of the bearing platform and the support area of the top surface of the heightened bearing platform, so that the verticality of the support is guaranteed;

(4) constructing a bridge abutment foundation;

and repairing the bridge abutment enlarged foundation by using concrete, and pouring along the transverse bridge direction. When concrete is poured, the original foundation is subjected to scabbling treatment, and the concrete is fully wetted by water.

Further, step three further includes:

(1) arranging a steel support;

arranging a jacking bracket system between an upper column embracing beam and a lower column embracing beam of the jacking bridge pier column; the bridge abutment is provided with a steel support on the bearing platform, and the top of the support is provided with a steel distribution beam;

(2) a structural support system;

the support system comprises: a supporting steel cylinder, a steel cushion block and a horizontal connecting rod;

the main body of each pier column jacking support adopts a steel pipe as a support rod. Flanges are welded at the upper end and the lower end of the steel pipe, and connecting components are welded on the side surfaces of the steel pipe; the lower part of each steel pipe support is connected with the column-embracing beam through an implantation or embedded anchor bolt;

(3) installing a steel support;

1) installing a steel support;

according to the anchor bolts anchored on the top surface of the bearing platform, mounting the steel supports on the foundation bolts according to the initial height, adjusting the verticality of the steel supports, controlling the verticality deviation to be less than 0.1%, and completely fastening the foundation bolts;

2) installing a steel cushion block;

the jacking steel cushion block is used between the jack and the temporary support; the steel cushion blocks correspond to the steel pipes of the jacking bracket system, and flanges are welded at two ends of the steel cushion blocks;

each supporting top is provided with a pair of wedges and steel plates with different thicknesses so as to meet the requirements of different jacking heights; in order to avoid support instability in the jacking process, the steel cushion blocks are connected through flanges;

when the jacking heights respectively reach the preset heights, a section of steel pipe support is added to replace a steel cushion block so as to enhance the support stability; the steel cushion blocks are connected by bolts, the steel pipe supports are connected with the bearing platform by bolts, and the steel pipe supports and the steel cushion blocks are connected by bolts;

(4) mounting a bridge bottom joist and a jack at the bridge abutment;

1) installing a distribution beam;

the distribution beam is fixed at the bottom of the beam body and positioned between the beam body and the jack, directly bears the weight of the upper beam body and transfers the force to the jack;

installing the distribution beam on the bottom of the beam by matching a chain block, drilling bolt holes at a beam seam, installing channel steel at the bridge floor, connecting a bottom joist and a top channel steel beam at the beam seam by using bolts, and fixing the joist at the bottom of the beam; after the beam falls, bolts and weights are arranged, and the bolt holes are filled with concrete with the same label as the beam body;

2) installing a jack;

jack grouping and displacement sensor: the jack of the connecting pier is divided into four groups, the rest piers are divided into two groups, and the rest piers are divided into sixteen groups, each group of jack is provided with a monitoring point, and each monitoring point is provided with a monitoring displacement sensor;

all jacks are installed in the downward direction, namely, the jack bases are fixed on the distribution beam below the beam;

when the jack is installed, the axis of the jack is ensured to be vertical;

the upper and lower of the jack are provided with steel backing plates to disperse the concentrated force, so that the structure is not damaged.

In the jacking process, the center of the jack deviates from the supporting center, and the jack is adjusted to be centered with the supporting center; if the jack rotates, a wedge block is added at the tail of the jack to level the jack.

Further, the fourth step further includes:

the limiting device is anchored on the lower column-embracing beam by four angle steels, and the angle steels at the top connect the lower column-embracing beam into a lattice form, so that the overall rigidity is increased;

a 5mm gap is reserved between the upper column-holding beam and the four angle steels and is used as a limit value for controlling the position deviation of the plane;

the abutment position is limited, I-shaped steel can be arranged on back walls on two sides of the abutment, and the I-shaped steel is used for bracing;

during jacking, the clamping grooves are formed in the plate girder, the gap between the plate girder and the limiting steel structure is set to be 3mm, so that the bridge abutment part girder body slides along the limiting set track in the jacking process, and the plane position of the bridge abutment part girder body is limited within the range of the reserved gap.

Further, step five further includes:

configuring jacking control points and controlling areas;

the control area is provided with a stay wire sensor to control the synchronism of displacement, and the synchronous precision of the displacement is controlled to be 2mm according to the structure of the bridge; the displacement sensor is connected with the central controller to form closed-loop control of displacement;

the displacement sensor is fixed on the central line of the support on the side surface of the pier stud and connected with the bottom of the beam, and when the beam body is jacked, the jacking height of the beam body is recorded and the displacement and the posture of the beam body are controlled;

before formal jacking, carrying out trial jacking;

before jacking, breaking the bridge deck connection at the jacking construction position, chiseling off cast-in-place concrete at the bridge deck position, and then cutting off connecting reinforcing steel bars to release the connection between the two sets;

checking the transverse limit and the longitudinal limit and observing the jacking test stage to check whether the limit system normally operates;

checking the erected jacking bracket; after the trial jacking is finished, providing conditions such as overall attitude, structural displacement and the like, and providing a basis for formal jacking;

after jacking is tried, if no problem exists, formal jacking is carried out;

in the jacking process, loading and jacking are carried out according to a preset load; observing that each observation point can reflect the measurement condition in time; checking and analyzing data in the jacking process, and if the data has a data deviation, adjusting in time;

the jacking process adopts alternate jacking, the beam body is in a state of being alternately supported by two groups of jacks, when the two groups of jacks are alternately supported, the displacement of the beam body is in a controllable state, the compression amount of the supporting system is changed within a threshold range under each group of supporting state, and the internal force of the beam body is changed within the threshold range.

Further, the alternative jacking method includes:

A. two groups of jacks are arranged at the bottom of a bridge structure to be jacked, so that pistons of the jacks are arranged downwards, and steel supporting cushion blocks with equal heights are arranged at the bottoms of the pistons in a cushioning manner;

B. arranging a plurality of displacement sensors on the bridge structure for measuring the jacking height of the bridge structure in real time;

C. controlling a hydraulic pump station to drive a first group of jacks to jack a bridge structure for one stroke through a control console, simultaneously gradually adding and padding a 1.2 cm-thick steel plate on the lower side of a second group of jacks in the jacking process to protect the stability of a support when the first group of jacks fail, taking out the steel plate after jacking to one stroke, and padding a steel supporting cushion block with a corresponding height at the lower end of a piston of the second group of jacks;

D. controlling a hydraulic pump station to drive a second group of jacks to jack up the bridge structure for one stroke through a control console, simultaneously controlling the first group of jacks to retract the cylinders, and arranging steel supporting cushion blocks with corresponding heights below the pistons of the first group of jacks after the cylinders are retracted;

E. and repeating the step C, D to repeatedly and alternately lift the bridge structure until the bridge structure is lifted to the preset height.

In the step C or D, the steel supporting cushion blocks which are overlapped and padded up and down are connected and fixed through connecting bolts.

In step C or D, the adjacent steel supporting cushion blocks are connected and reinforced into a steel lattice form through connecting rods.

Further, step six further includes:

pier column connection;

the bridge piers are connected by reinforced concrete, and a layer of reinforced concrete is coated outside the bridge piers to increase the rigidity of the pier bottom; when in construction, chiseling the steel bars of the upper and lower cutting surfaces by 20cm, connecting the longitudinal steel bars within the jacking height range by the upper and lower steel bars in a steel bar mechanical connection mode, and constructing the stirrups according to a preset mode; after the binding of the reinforcing steel bars is finished, fully wetting the upper and lower concrete crops with water, and pouring micro-expansion fine grain type concrete in a vertical mold; after the concrete of the connecting column reaches the preset strength, the template is removed, longitudinal steel bars wrapped with reinforced concrete are implanted on the column holding beam, stirrups are bound, and concrete is poured in the vertical mold;

constructing a bridge abutment;

the abutment adopts a method of embedding ribs into abutment caps and side walls and pouring heightening cushion stones, C30 concrete is adopted for abutment heightening, the original abutment is subjected to chiseling treatment before construction, the chiseling depth is about 1cm, all blocks of the original abutment are chiseled off, and the connecting and embedding depth of new and old concrete is 20 cm;

(1) carrying out bar planting construction;

steel bars are implanted into the rear side and the top surface of the bearing platform;

(2) carrying out bar planting construction;

the steel bars adopted by the steel bar planting are HRB335 steel bars;

measuring the bar planting position on the component by using a steel ruler tool, and marking the concrete bar planting position by using ink;

measuring the position of the original bridge steel bar by combining a steel bar positioning instrument according to the marked embedded steel bar position, and drilling holes at the embedded steel bar position by using an electric drill without impact force;

after drilling and forming holes, firstly, removing floating slag in the holes by using a brush, and then removing floating dust in the holes by using compressed air;

according to the mixing proportion of the special bar-planting glue solution, the bar-planting glue solution is prepared on site, the prepared glue solution is injected into a pore channel of a drilled hole, and the steel bar is rotated in one direction and slowly inserted into the bottom of the hole;

checking whether the appearance has a gummosis phenomenon, whether the glue injection is full and whether the curing is normal;

the drilling and bar planting inspection is carried out with drawing test inspection except appearance judgment, when all the requirements are met, other steel bars are bound, and finally a template is installed for pouring C30 expanded concrete; when concrete is poured, the concrete is slowly discharged and is densely compacted by layered vibration.

Further explaining, a PLC is adopted to control the variable frequency synchronous system to execute jacking construction;

PLC control frequency conversion synchronization system includes: the system comprises a plurality of jacking jacks 1, a central controller 8, a distribution valve 9, an oil tank 11, a computer 12, displacement sensors 2, an oil return switch 3, a pressure reducing valve 4, an oil return pipe 5 and an oil inlet pipe 6, wherein the displacement sensors 2, the oil return switch 3, the pressure reducing valve 4, the oil return pipe 5 and the oil inlet pipe 6 are respectively matched with the jacking jacks 1;

the central controller 8 is respectively connected with each displacement sensor 2 through a sensing wire 7;

a variable frequency pump station 10 is arranged on the oil tank 11;

the PLC control frequency conversion synchronous system is provided with a computer control system of a Windows user interface;

the PLC controls the frequency conversion synchronous system to obtain displacement and load information in the construction process through an industrial bus, the displacement and load information is displayed on a screen in real time, and various information in the construction process is recorded in a computer in real time;

the PLC controls the frequency conversion synchronous system to be configured with displacement error control; controlling a stroke; controlling the load pressure; an emergency stop function; automatic protection by misoperation; the PLC control frequency conversion synchronous system is configured to operate all the oil cylinders simultaneously or operate one oil cylinder singly.

Further, the PLC controlled frequency conversion synchronization system further includes: a multipoint synchronous hydraulic control system;

the multipoint synchronous hydraulic control system is provided with a plurality of hydraulic control units, each hydraulic control unit is used as a control substation, is connected together by an industrial control bus, is controlled by a main controller and synchronously operates in cooperation;

the multipoint synchronous hydraulic control system is also provided with a plurality of main controllers, each main controller can control 36 substations, each substation is provided with four independent closed-loop control loops, and each closed-loop control loop forms a position closed loop or a force closed loop;

when the position closed-loop working state is selected, the instruction value input by the industrial control bus is the position, and the position detection feedback element is used by configuring a displacement sensor;

when the force closed loop working state is selected, the industrial control bus inputs an instruction as force, and the multipoint synchronous hydraulic control system is also provided with a pressure sensor and a force detection element.

According to the technical scheme, the invention has the following advantages:

the integral synchronous jacking transformation method of the overpass provided by the invention realizes the continuous operation of jack alternate jacking, so that the safety is controllable.

The alternate jacking is adopted in the jacking process, the beam body is in a state that two groups of jacks alternately support the beam body, when the two groups of jacks alternately support the beam body, the displacement of the beam body is in a controllable state, and under the supporting state of each group, the compression amount of the supporting system hardly changes, so that the internal force of the beam body hardly changes. Under the operation mode, the displacement of the beam body is continuously in a controlled state from the beginning to the end of jacking. The pressure of each jack is continuously monitored, so that the beam body is not damaged in the jacking process, the whole supporting system including the beam body is also in a monitoring state, and the whole bridge jacking system is also in a safe and controllable state.

The jacking adopts a PLC hydraulic synchronous operating system with consistent precision, the PLC control hydraulic synchronous jacking is a jacking method for comprehensively controlling force and displacement, the control method is established on the basis of double closed loop control of force and displacement, the hydraulic jacks accurately jack the bridge stably according to the actual load of the bridge, so that the additional stress on the bridge in the jacking process is reduced to the minimum, meanwhile, the hydraulic jacks are grouped according to the distributed positions and form a position closed loop with corresponding displacement sensors so as to control the displacement and the posture of the jacking of the bridge, and the synchronous precision is +/-2.0 mm, so that the synchronism of the jacking process can be well ensured, and the structural safety of a beam body in jacking is ensured.

The invention adopts a computer system for monitoring, safe and reliable construction guidance, and the hydraulic system is controlled by the computer, can fully automatically complete synchronous displacement, and realizes multiple functions of force and displacement control, operation locking, process display, fault alarm and the like. The whole operation control is realized by the operation desk which is controlled by a computer, and the information such as displacement, load and the like in the construction process is visually displayed on a large color screen of a control room in real time through an industrial bus, so that people can see the information at a glance, and various information in the construction process is recorded in the computer in real time and is stored for a long time. Because real-time monitoring is realized, the safety and the reliability of the engineering are ensured, and the construction conditions are greatly improved.

The invention has no damage to the whole structure after jacking, and ensures the original appearance of the beam slab and the bridge deck. In the jacking process, the additional stress of the main beam is in a reasonable range, no new crack appears, the width of the original crack is not obviously increased, and the related standard requirements are met.

After the bridge abutment is jacked in place, under the action of the jack and the steel support system, the cut pier stud can be immediately connected and installed with steel bars, the expansion concrete is poured, and the abutment can be simultaneously heightened by abutment caps. During the period, the construction of the road surface sequential connection can be synchronously carried out after the platform. After the age of the concrete is not less than 15 days, the supporting system can be removed to recover the bridge deck traffic, and the influence on the existing traffic is greatly reduced.

The invention is suitable for series of projects which have insufficient clearance under the existing overpass and need to be subjected to integral lifting construction under the condition of traffic, navigation or other conditions. The method is suitable for existing overpass disease treatment and needs underpinning or reinforcing series of projects.

The invention adopts a process principle that a plurality of vertical jacks are adopted, jacking acting points are arranged on upper and lower holding beams of pier upright posts, the acting points at the bridge abutment are arranged between a bridge abutment bearing platform top and a beam slab lower distribution beam, a PLC hydraulic synchronous control operation system is adopted, after the upright posts are supported in place by the upper and lower holding beams, the root parts of the upright posts are cut off by a rope saw, the jacks are alternatively jacked, and the whole bridge floor is lifted to a preset height.

Drawings

In order to more clearly illustrate the technical solution of the present invention, the drawings used in the description will be briefly introduced, and it is obvious that the drawings in the following description are only some embodiments of the present invention, and it is obvious for those skilled in the art that other drawings can be obtained based on these drawings without creative efforts.

FIG. 1 is a flow chart of an overall synchronous jacking transformation method of an overpass;

FIG. 2 is a schematic view of a landing bolt arrangement;

FIG. 3 is a layout view of a pier supporting system;

fig. 4 is a layout view of a pier supporting system;

FIG. 5 is a layout view of a pier supporting system;

FIG. 6 is a flow chart of a steel support installation process;

FIG. 7 is a schematic view of a steel shim block;

FIG. 8 is a schematic view of a steel shim block;

FIG. 9 is a schematic view of a distributor beam;

FIG. 10 is a schematic view of a distributor beam;

FIG. 11 is an elevational view of the jack as initially installed;

FIG. 12 is an elevation view of the jack after jacking;

FIG. 13 is a schematic view of the stop installation in the abutment position;

FIG. 14 is a jacking flow chart;

FIG. 15 is a schematic view of a bridge construction jacking system and configuration prior to jacking;

FIG. 16 is a schematic diagram illustrating a state of jacking by the first set of jacks;

FIG. 17 is a schematic view of a second set of jacks with blocks;

FIG. 18 is a schematic view showing the state of the second set of jacks for jacking and the first set of spacers;

FIG. 19 is a diagram showing the first set of jacks re-jacking and the second set of additional blocks;

FIG. 20 is a flow chart of a bar planting construction process;

FIG. 21 is a schematic connection diagram of an LC hydraulic synchronous jacking control system;

FIG. 22 is a schematic diagram of proportional synchronous jacking for bridge reconstruction.

Detailed Description

In order to make the objects, features and advantages of the present invention more obvious and understandable, the technical solutions of the present invention will be clearly and completely described below with reference to specific embodiments and drawings. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the scope of protection of this patent.

The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the description in this document. As used herein, the singular forms "a", "an" and "the" are intended to include the plural forms as well, unless the context clearly indicates otherwise. It will be further understood that the terms "comprises" and/or "comprising," when used in this specification, specify the presence of stated features, integers, steps, operations, elements, and/or components, but do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and/or groups thereof.

The invention provides an integral synchronous jacking transformation method for an overpass, which specifically comprises the following steps of: construction preparation;

the expansion joints at the bridge abutments at the two ends of the bridge floor are removed and disconnected, the rest expansion joints and beam joints of the bridge floor do not need to be processed, steel pipe piles are adopted to set hard isolation protection at the positions 2m away from the existing line within the construction range of 20m at the two sides of the existing line, the length of each steel pipe pile is 2m, and the steel pipe piles are buried underground by 0.5 m.

Constructing a pier foundation; specifically, a counterforce foundation of a jacking support system is arranged on a lower column embracing beam, after jacking is completed, the lower column embracing beam is buried under the ground and used as a permanent structure, earthwork at the plane position of the lower column embracing beam is removed, a tapered slope needs to be excavated on a bridge abutment, earthwork at the foundation part of the bridge abutment is enlarged and is cleaned, and a steel support is convenient to install.

The earthwork adopts small machinery to assist in manual excavation, and needs to be used for backfilling earthwork to be manually transported to the peripheral position of the site for stacking.

Roughening the surfaces of the pier stud and the abutment foundation; because the upper and lower column-embracing beams need to be poured after jacking, in order to ensure that new and old concrete of the bearing platform are effectively combined, a steel chisel is manually adopted to chisel the original concrete in the preset position of the pier column and the range of the bearing platform of the abutment foundation, the surface layer of the original concrete needs to be chiseled when chiseling, and the difference of the chiseling unevenness is not less than 6 mm.

Anchoring the supporting anchor; as shown in fig. 2, the jacking reaction force bracket is disposed on the pillar beam, and an anchor 101 is disposed on the top surface of the pillar beam. The abutment platform of the simulated bridge adopts an anchoring part for punching and planting anchor bolts, and the pier 102 can adopt an embedded anchor bolt method because of the construction of reinforced concrete structures of upper and lower embracing column beams. The steel plate with the same size as the steel barrel supporting flange is adopted to accurately position the anchoring part, the diameter of the flange bolt hole of the steel supporting column is 26mm, the diameter of the anchor bolt is 24mm, and 16 anchor bolts are completely installed in place in the installation process, so that the maximum deviation of the connection of the steel supporting columns is 1 mm. And after the anchoring piece construction is finished, mortar leveling treatment is carried out on the top surface of the bearing platform and the area of the bracket on the top surface of the heightened bearing platform, so that the vertical degree of the bracket is ensured.

Constructing a bridge abutment foundation; the existing bridge abutment plane position can not be provided with a jack steel support, the bridge abutment enlarged foundation is repaired by concrete, the width of the repair concrete is 0.5m, the height of the repair concrete is 0.75m, and the repair concrete is poured along the transverse bridge direction. When concrete is poured, the original foundation is subjected to scabbling treatment, and the concrete is fully wetted by water.

Constructing a support bracket system;

(1) arranging a steel support; arranging a jacking bracket system between an upper column embracing beam and a lower column embracing beam of the jacking bridge pier column; the bridge abutment is provided with a steel support on the bearing platform, and the top of the support is provided with a steel distribution beam;

(2) a structural support system; the jacking steel support bracket system mainly plays a role in bearing the weight of the upper structure bridge body, the bearing capacity, rigidity and stability of the jacking steel support bracket system need to be considered, the mechanical property of the bracket system meets the standard requirement when the bridge body is jacked, and meanwhile, the stress state of the bridge body in the jacking process meets the preset requirement, including additional stress, displacement and the like.

The bracket system comprises a supporting steel cylinder, a steel cushion block, a horizontal connecting rod and the like. The main body of each pier column jacking support adopts a finish machining phi 500 multiplied by 12mm steel pipe as a support rod. Flanges with the thickness of 20mm are welded at the upper end and the lower end of the steel pipe, and connecting members are welded on the side faces of the steel pipe. The lower part of each steel pipe support is connected with the column-embracing beam (original bearing platform) through an implanted or embedded M16 anchor bolt. The detailed arrangement is shown in the arrangement diagrams of the bracket system in fig. 3, 4 and 5.

(3) Installing a steel support;

1) installing a steel support;

according to the anchor bolts anchored on the top surface of the bearing platform, the steel supports are installed on the foundation anchor bolts according to the initial height (h is the height from the bottom of the beam to the top surface of the bearing platform-the height after the jacking jacks and the beam are supported), the perpendicularity of the steel supports is adjusted, the perpendicularity deviation of the steel supports is controlled to be less than 0.1%, and the foundation anchor bolts are fastened completely. The steel support and the longitudinal and transverse connection are processed in a factory and installed manually in a matching manner on site. The process flow chart of the steel support installation process is shown in figure 6.

2) Installing a steel cushion block;

the special jacking steel cushion block is used between the jack and the temporary support. The steel cushion block corresponds to a steel pipe of the jacking bracket system, a phi 500 multiplied by 12mm steel pipe is also adopted, and flanges with the thickness of 12mm are welded at two ends. Each temporary support top is provided with a pair of wedges and steel plates with different thicknesses so as to meet the requirements of different jacking heights. In order to avoid support instability in the jacking process, the steel cushion blocks are connected through flanges.

In order to adapt to the jacking stroke of the jack, the steel cushion blocks have the heights of 10cm, 20cm, 50cm and the like, and are shown in fig. 7 and 8.

When the jacking heights reach 1.0 meter respectively, a section of steel pipe support is added to replace a steel cushion block, so that the support stability is enhanced. The support structures are firmly connected, namely the steel cushion blocks are connected by bolts, the steel pipe supports are connected with the bearing platform by bolts, and the steel pipe supports and the steel cushion blocks are connected by bolts. Through the measures, the support structure is guaranteed to have good integrity, and instability damage of a support system caused by slippage possibly occurring due to bridge jacking is prevented.

(4) Mounting a bridge bottom joist and a jack at the bridge abutment;

1) installing a distribution beam;

as shown in fig. 9, the distribution beam is fixed at the bottom of the beam body between the beam body and the jack, and directly bears the weight of the upper beam body and transfers the force to the jack. The distributing beam needs to have sufficient rigidity, strength and stability, so that large deformation is not generated in the jacking process, meanwhile, in the jacking process, the beam body has longitudinal displacement, the distributing beam moves along with the beam body, but the jack and the lower steel support system are fixed in position and do not generate horizontal displacement, the jack and the distributing beam slide relatively, and the eccentric compression, local instability and the like of the beam body need to be considered. As shown in fig. 10, No. 1 reinforcing plate and No. 2 reinforcing plate are provided on the distribution beam.

The distribution beam is installed on the bottom of the beam by matching a chain block, bolt holes are drilled at the beam seams, channel steel is installed at the bridge floor for measurement, the bottom joist and the top channel steel beam are connected well at the beam seams by bolts, and the joist is fixed at the bottom of the beam. After the beam falls, bolts and weights are added, and the bolt holes are filled with concrete with the same mark number as the beam body.

2) Installing a jack;

the selection of the jack is related to the size of the steel support, the local compression of the concrete, the stress of the upper beam body and the like, and whether the steel support, the local compression of the concrete and the stress of the upper beam body meet the requirements or not when one jack fails is considered. The jack can be 200T tonnage jack, 300T tonnage jack, 500T tonnage jack, etc. The jacks are all provided with hydraulic locks and mechanical locks, so that decompression of systems and pipelines in any form can be prevented, and effective support of loads is guaranteed.

Jack grouping and displacement sensor: the jacks of the cross pier are divided into four groups, the rest jacks of each pier are divided into two groups, and the rest jacks are divided into sixteen groups (6 x 2+1 x 4), each group of jacks is provided with a monitoring point, and each monitoring point is provided with a monitoring displacement sensor. In order to facilitate the jacking operation, all the jacks are installed in the downward direction, namely, the jack bases are fixed on the distribution beam below the beam.

When the jack is installed, the axis of the jack is ensured to be vertical. So as to avoid generating horizontal component force in the jacking process due to the installation and inclination of the jack. The upper and lower of the jack are provided with steel backing plates to disperse the concentrated force, so that the structure is not damaged.

Leveling and centering the jack, if the center of the jack deviates from the supporting center in the jacking process, the centering supporting center of the jack needs to be adjusted, and if the jack rotates, a wedge-shaped block needs to be added at the tail of the jack to level the jack, as shown in fig. 11 and 12.

In the construction process of the limiting system, a limiting device is required to be arranged in order to ensure that a bridge does not deviate in the jacking process. If plane deflection is generated in jacking, the structure of the limiting device is controlled within the range set by the limiting device. The bridge jacking is a dynamic process, and the horizontal displacement of the beam body is ensured not to be generated at any time.

The limiting device is anchored to the lower column-embracing beam by four L125 x 10 angle steels as shown in figure 13, and the top of the limiting device is connected into a lattice form by the L100 x 10 angle steels, so that the overall rigidity is increased. And 5mm gaps are reserved between the upper column-holding beam and the four L125 x 10 angle steels and are used as the limit value of the position deviation of the control plane. The length of the four L125 x 10 angle steels must meet the requirement that the angle steels can still play a limiting role after jacking is completed, and therefore the length of the angle steels is 2.8 m. Not less than the distance between the upper and lower column embracing beams, the thickness of the upper column embracing beam and the jacking height.

The abutment position limiting can be realized by installing I20a I-steel with the length of 1.2m on back walls at two sides of the abutment and using I16I-steel diagonal braces. During jacking, the clamping grooves are formed in the plate girder, the gap between the plate girder and the limiting steel structure is set to be 3mm, so that the bridge abutment part girder body slides along the limiting set track in the jacking process, and the plane position of the bridge abutment part girder body is limited within the range of the reserved gap.

The jacking construction related by the invention has the advantages that the principle of dividing control points is that the jacking process is safe and reliable, and particularly the synchronism and the attitude control of a bridge body are emphasized. Configuring jacking control points and controlling areas; the control area is provided with a stay wire sensor to control the synchronism of displacement, and the synchronous precision of the displacement is controlled to be 2mm according to the structure of the bridge; the displacement sensor is connected with the central controller to form closed-loop control of displacement;

the displacement sensor is fixed on the center line of the support on the side surface of the pier stud and connected with the bottom of the beam, and when the beam body is jacked, the jacking height of the beam body is recorded and the displacement and the posture of the beam body are controlled.

Before formal jacking, carrying out trial jacking; before jacking, the bridge deck connection at the jacking construction position is broken to ensure that the replacement of the support does not affect the structure of adjacent spans, cast-in-place concrete at the bridge deck is chiseled firstly, and then the connection steel bars are cut off to release the connection between the two links. If the relationship between the mobile unit and the fixed unit is released earlier. Before jacking is tried, checking is needed, and smooth operation of jacking is guaranteed. And (4) checking the transverse limit and the longitudinal limit and observing the jacking test stage. And checking whether the limiting system normally operates. The built jacking support is checked to ensure enough strength, rigidity and stability, the mid-span deflection of the support is less than 10mm, and the support is ensured not to collapse, not to incline, to have small settlement and to be uniform when the beam is jacked. After the trial jacking is finished, the conditions such as the whole posture, the structure displacement and the like are provided, and a basis is provided for formal jacking.

After jacking is tried, if no problem exists, formal jacking is carried out, as shown in fig. 14;

the jacking process adopts alternate jacking, the beam body is in a state of being alternately supported by two groups of jacks, the displacement of the beam body is in a controllable state when the two groups of jacks are alternately supported, and the compression amount of the support system is hardly changed under the supporting state of each group, so that the internal force of the beam body is hardly changed.

And (3) formally jacking, wherein the following procedures are required to be carried out and recorded: loading and jacking according to a preset load; each observation point is used for reflecting the measurement condition in time; each measuring point needs to make measurement work carefully to reflect the measurement data in time; comparing the difference between the measured data and the theoretical data; and (3) analysis: if there is a data deviation, all the parties concerned should be carefully analyzed and timely adjusted.

Alternative jacking (Key working procedure of formal jacking)

The alternate jacking is adopted in the jacking, the beam body is in a state that two groups of jacks alternately support in the jacking process, the displacement of the beam body is in a controllable state when the two groups of jacks alternately support, and the compression amount of the support system hardly changes in each group of support states, so that the internal force of the beam body hardly changes. Under the operation mode, the displacement of the beam body is continuously in a controlled state from the beginning to the end of jacking. The pressure of each jack is continuously monitored, so that the beam body is not damaged in the jacking process, and the whole supporting system including the beam body is also in a monitoring state. Therefore, the whole bridge jacking system is also in a safe and controllable state.

The bridge structure jacking system and the jacking method have the advantages that two groups of jacks capable of actively exerting jacking force are arranged at the bottom of the bridge structure, the hydraulic pump station is controlled by the control console to drive the two groups of jacks to jack up repeatedly and alternately, and meanwhile, in the jacking process of one group of jacks, the bottom of the other group of jacks is padded with the steel supporting cushion block, so that the height difference problem among supporting points is eliminated, and the structural safety in the jacking process of the bridge structure is effectively guaranteed.

Referring to fig. 15 to 19, the jacking system for a bridge structure mainly includes: the two groups of jacks 1a and 1b are respectively installed at the bottom of the bridge structure 202 to be jacked, and the pistons of the jacks 1a and 1b are arranged downwards, of course, each jack 1a and 1b is provided with a protection device such as a safety valve, and the jacks 1a and 1b can keep the corresponding pressure even if sudden failure, power failure and the like of an oil supply system and an oil return system occur; the steel supporting cushion blocks 30 are respectively overlapped and cushioned on the lower parts of the pistons of the two groups of jacks 1a and 1 b; the displacement sensors 2 are respectively arranged on the bridge structure 2 and used for measuring the jacking height of the bridge structure 2 in real time; the hydraulic pump station 50 receives the measured height of the displacement sensor 2 and transmits the measured height to the control console 60, and the control console 60 controls the hydraulic pump station 50 to operate and alternatively lift the two groups of jacks 1a and 1 b. The steel supporting cushion blocks 30 which are overlapped mutually penetrate through holes around the steel supporting cushion blocks through connecting bolts and are fastened through nuts, so that the upper and lower users are connected and fixed. And the adjacent steel supporting cushion blocks 30 are connected and reinforced into a steel lattice form through connecting rods, so that the stability of the whole supporting system during jacking is ensured.

As shown in fig. 15 to 19, the jacking method of the jacking system is as follows:

installing two groups of jacks 1a and 1b at the bottom of a bridge structure 202 (such as a bridge) to be jacked, enabling pistons of the jacks to be arranged downwards, and respectively padding equal-height steel supporting cushion blocks 30 at the bottoms of the pistons of the two groups of jacks 1a and 1 b; a plurality of displacement sensors 2 are arranged on the bridge structure 2 and used for measuring the jacking height of the bridge structure 2 in real time; then, the control console 60 controls the hydraulic pump station 50 to drive the first group of jacks 1a, the jacks on the two outer sides in fig. 16 to jack the bridge structure 202 for one stroke, and the lower ends of the pistons of the second group of jacks 1b are padded with steel supporting cushion blocks 30 with corresponding heights, the number of the cushion blocks padded in fig. 17 is equal to one stroke, so that the steel supporting cushion blocks 30 can effectively support the second group of jacks 1 b; at this time, the second group of jacks 1b is controlled to jack the bridge structure 202 for one stroke, meanwhile, the first group of jacks 1a is controlled to retract cylinders, steel supporting cushion blocks 30 with corresponding heights are arranged at the lower ends of the pistons of the first group of jacks 1a in a cushioning mode, the number of the cushion blocks added in the figure 18 is two, and the steel supporting cushion blocks 30 are used for effectively supporting the first group of jacks 1 a; and then controlling the first group of jacks 1a to jack the bridge structure 202 for one stroke, simultaneously controlling the second group of jacks 1b to retract cylinders, and arranging two steel supporting cushion blocks 30 at the lower ends of the pistons of the second group of jacks 1b in a cushioning manner, as shown in fig. 19, and finally jacking the bridge structure 2 to a preset height through repeated alternate circulation.

In the jacking process, the alternate circulating jacking of the two groups of jacks 1a and 1b eliminates the compression amount of a bracket system of the steel supporting cushion block 30 at any time, and when any one group of jacks releases pressure, the other group of jacks starts to extend the cylinder for jacking, so that the problem of height difference between supporting points is solved. Meanwhile, if the jack fails in an emergency, the falling of the upper heavy load is eliminated without fall due to the elimination of the supporting compression amount, the load underpinning is completed immediately, the safety of the upper heavy load is effectively ensured, the structural safety in jacking is also effectively ensured, the jacking bridge structure 2 can realize jacking, slope changing, descending and deviation rectifying according to the procedures expected by people, and the effect that the service function of the bridge structure 2 is not reduced after jacking is achieved.

In the invention, pier columns are connected;

the bridge piers are connected by reinforced concrete, and a layer of reinforced concrete is coated outside the bridge piers to increase the rigidity of the pier bottom; when in construction, the reinforcing steel bars of the upper and lower cutting surfaces are chiseled out by 20cm, the upper and lower reinforcing steel bars are connected with the longitudinal reinforcing steel bars within the jacking height range in a reinforcing steel bar mechanical connection mode, and the stirrups are constructed; after the binding of the reinforcing steel bars is finished, fully wetting the upper and lower concrete crops with water, and pouring micro-expansion fine grain type concrete in a vertical mold; after the concrete of the connecting column reaches the preset strength, the template is removed, longitudinal steel bars wrapped with reinforced concrete are implanted on the column holding beam, stirrups are bound, and concrete is poured in the vertical mold;

constructing a bridge abutment;

(1) carrying out bar planting construction;

(2) carrying out bar planting construction; the process flow of the bar planting construction is shown in fig. 20.

The reinforcing bar that the bar planting adopted is the HRB335 reinforcing bar, and the bar planting reinforcing bar carries out physics cold working at small-size machines such as cutting machine, angle bending machine for the steel bar processing canopy according to presetting the requirement. The bar planting glue adopts A-grade glue.

And (4) setting out the steel bar planting position according to a construction preset diagram, measuring the steel bar planting position on the component by using tools such as a steel ruler and the like, and marking the specific steel bar planting position by using ink.

According to the bar planting position of the identification, the original bearing platform construction preset diagram is referred, the original bridge steel bar position is measured by combining a steel bar positioning instrument, the conflict with the original bridge steel bar is avoided as much as possible, and the electric drill without impact force is used for drilling at the bar planting position.

A-level bar planting adhesive performance index

Note: the performance indexes in the table are average values except for the standard value of strength.

Hole cleaning: after the holes are drilled and formed, the floating slag in the holes is removed by a brush, and then the floating dust in the holes is removed by compressed air.

And (3) bar planting: according to the mixing proportion of the special bar-planting glue solution, the bar-planting glue solution is prepared on site, the prepared glue solution is injected into the pore channel of the drilled hole, and the reinforcing steel bar is rotated in one direction and slowly inserted into the bottom of the hole.

Checking whether the appearance has a glue flowing phenomenon or not, whether the glue injection is full or not and whether the solidification is normal or not.

Before the bar planting binder is not cured, the steel bars cannot be disturbed, otherwise the bar planting effect is influenced.

And (4) performing tensile test inspection on the drilled and embedded steel bars except for appearance judgment, binding other steel bars when all the steel bars meet the requirements, and finally installing a template and pouring C30 expanded concrete. Slowly discharging materials when pouring concrete, and densely vibrating in layers

According to the dismantling equipment, in the process of chiseling off the column-holding beam, after the jacking is finished, after the concrete at the high-connection part of the pier column reaches the preset strength, the equipment such as the jacking jack and the steel distribution beam are dismantled, so that the load of the bridge structure is born by the pier column again. The traffic limits are listed in an uninvably intrusive way during equipment removal.

The invention also adopts a PLC to control a frequency conversion synchronous system to execute jacking construction;

PLC control frequency conversion synchronization system includes: the device comprises a plurality of jacking jacks (1), a central controller (8), a distribution valve (9), an oil tank (11), a computer (12), displacement sensors (2), an oil return switch (3), a pressure reducing valve (4), an oil return pipe (5) and an oil inlet pipe (6), wherein the displacement sensors (2), the oil return switch (3), the pressure reducing valve (4), the oil return pipe (5) and the oil inlet pipe are respectively matched with the jacking jacks (1);

the central controller (8) is respectively connected with each displacement sensor (2) through a sensing wire (7); a variable frequency pump station (10) is arranged on the oil tank (11); the PLC control frequency conversion synchronous system is provided with a computer control system of a Windows user interface; the PLC controls the frequency conversion synchronous system to obtain displacement and load information in the construction process through an industrial bus, the displacement and load information is displayed on a screen in real time, and various information in the construction process is recorded in a computer in real time; the PLC controls the frequency conversion synchronous system to be configured with displacement error control; controlling a stroke; controlling the load pressure; an emergency stop function; automatic protection by misoperation; the PLC control frequency conversion synchronous system is configured to operate all the oil cylinders simultaneously or operate one oil cylinder singly.

The multipoint synchronous hydraulic control system adopts frequency conversion speed regulation proportional control, and relies on a built-in PLC to form a force or position closed loop, thereby realizing various high-precision multipoint synchronous jacking and pushing control and meeting the requirement of force balance among various points.

The multi-point synchronous hydraulic control system adopts a modular structure, a user can select one point, two points, four points and various different hydraulic control units according to construction requirements, each hydraulic control unit is used as a control substation, is connected together by an industrial control bus, is controlled by a main controller and works synchronously in a coordinated mode.

When the position closed loop working state is selected, the instruction value input by the industrial control bus is the position, and an external displacement sensor is needed to be used as a position detection feedback element; when the force closed loop working state is selected, the industrial control bus inputs an instruction as force, and a pressure sensor and a force detection element are already arranged in the hydraulic system. Whether a position closed loop or a force closed loop is used in actual use depends on the engineering object.

The invention relates to the hyperstatic problem of multipoint synchronization, when the multipoint synchronization exceeds two points in a collinear way or exceeds three points in a coplanar way, the hyperstatic problem can be met, the hyperstatic problem can be overcome only by simple position synchronization for a small-rigidity structure, but the synchronization requirement can be met by using a complex force balancing technology for a large-rigidity structure.

The small rigidity and the large rigidity refer to the control precision of the deformation of the component relative to the displacement of the oil cylinder; the synchronous system used by the invention has the control precision of more than 0.5mm, and if the error of 0.5mm occurs between two adjacent points and the load change of the oil cylinder does not exceed 5 percent, the oil cylinder can be regarded as a small-rigidity structure; if the error of 0.5mm occurs between two adjacent points, the load of the oil cylinder can be caused to change by more than 20%, and the structure with large rigidity is considered.

For the translation of the bridge structure, because the foundation subsidence phenomenon exists in the translation process, only a force closed loop jacking mode can be adopted. The force closed loop cannot control the posture of a construction object, so that a position closed loop is also used as an auxiliary in a working state of the force closed loop. If the jacking points are distributed in a straight line, only two position detection sensors are needed to control the posture of the construction object; when the jacking points are distributed on a plane, more than three position detection control points are needed.

The equal proportion synchronous jacking problem related by the invention, synchronous jacking in the reconstruction of the overpass, the approach bridge of the original overpass needs to be lifted to be connected with a new bridge, and the synchronous control of the 8 point position is used in the construction shown in FIG. 22, namely 1A,1B,2A,2B,3A,3B,4A,4B,5A,5B,6A,6B,7A,7B,8A and 8B.

Under the control of an industrial control bus network, an 8-point control system is controlled by one controller, and is lifted up in proportion to reach the preset position of a new bridge.

The safety protection of synchronous jacking depends on the adoption of a balance valve, and the balance valve is of a leakage-free cone valve structure and has 3 main functions; the first function is to balance the load pressure of the oil cylinder, so that the jacking oil cylinder with load descending can not lose pressure and slide down, and the workpiece can not fall off even if the oil pipe is broken. Therefore, the oil inlet speed regulation is realized no matter the oil inlet speed regulation is carried out during ascending or descending, and the safety is greatly improved. The second function is to protect the oil cylinder from overload, when the pressure in the oil cylinder exceeds the set pressure, the balance valve can be automatically opened to discharge the over-high oil pressure, and the oil cylinder is protected from overload. The third function is that the heavy load is started first, and when the multiple cylinders are connected in parallel, the load of each cylinder is automatically balanced. The balance valve can be directly arranged on the oil cylinder, so that accidents caused by an external pipeline are reduced to the maximum extent.

The invention monitors the jacking bridge and carries out monitoring,

1) jacking monitoring part

a. A displacement sensor and a pressure sensor which are arranged on a PLC jacking control system belong to a real-time monitoring system;

b. other monitoring comprises cushion cap settlement, bridge deck elevation monitoring, bridge center line and the like, belongs to discontinuous monitoring, and provides certain basis for jacking control.

Construction monitoring point location and monitoring content meter

Serial number

Measuring point position

Number of measurement points

Monitoring content

Alarm value (preset supply)

Instrumentation and equipment

1

Bearing platform settlement

8

Relative elevation

2mm

Electronic level

2

Bridge floor elevation monitoring

8

Relative elevation

4mm

Electronic level

3

Bridge center line

6

Off-center line

10mm

Total station

2) Construction monitoring contents

a. And (3) carrying out settlement observation on a bearing platform: and setting a bearing platform settlement observation system to reflect the settlement condition of the bearing platform and timely making corresponding measures.

b. Observing the bridge deck elevation: and the bridge deck elevation observation points are used for calculating the actual jacking height of each pier. The measuring points are arranged on the bridge floor, and two measuring points are arranged on two sides of the bridge floor at the position of each pier stud, and the number of the measuring points is 8.

c. Bridge center line: and 2 points are arranged on the center line of the bridge deck of each hole, and the transverse offset of the bridge deck is measured at 6 points.

d. And (3) observing longitudinal displacement of the beam body: in order to observe the longitudinal displacement of the beam body and the verticality of the upright post in the jacking process, an ink line is used for popping up a vertical projection line on the outer side surface of the outer upright post, the ink line needs to be popped below a cutting surface, and a shot is hung at the top end of the vertical ink line. The longitudinal displacement of the beam body is judged by comparing the plumb sphere line with the ink line and compared with the calculated value.

3) Monitoring process control

a. A field technician and a jacking operator read initial readings before jacking construction in advance;

b. after jacking construction is started, carrying out comprehensive measurement and data recording on a displacement sensor, a longitudinal and transverse displacement observation point, a jacking jack and the elevation change condition of each elevation control point every 2 hours, adjusting jacking control parameters through comparison and analysis of monitoring data by field technicians to be compared with preset data, controlling in time, ensuring the integral posture of a beam body and the posture of a pier column, and arranging and reporting daily monitoring data and monitoring data to a head packet party and a supervision unit;

c. monitoring early warning and site constructors need to immediately inform site technicians to stop jacking operation after finding potential danger conditions, report the problem conditions to a project chief engineer in detail, the project chief engineer summons related technicians and a third party monitoring unit to compare monitoring data, possible reasons are jointly investigated, the chief engineer sends out a re-engineering instruction after the early warning is relieved, and the site can continue construction.

The process parameters and sequence of steps described and/or illustrated herein are given by way of example only and may be varied as desired. For example, while the steps shown and/or described herein may be shown or discussed in a particular order, these steps need not be performed in the order shown or discussed. Various example methods described and/or illustrated herein may also omit one or more of the steps described or illustrated herein, or include additional steps in addition to those disclosed.

The previous description of the disclosed embodiments is provided to enable any person skilled in the art to make or use the present invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the generic principles defined herein may be applied to other embodiments without departing from the spirit or scope of the invention. Thus, the present invention is not intended 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. The integral synchronous jacking transformation method for the overpass is characterized by comprising the following steps of:

firstly, construction preparation;

constructing a pier foundation;

thirdly, constructing a support bracket system;

fourthly, constructing a limiting system;

fifthly, jacking construction;

sixthly, pier reconstruction construction;

2. The method for integrally and synchronously jacking and transforming the overpass according to claim 1, wherein the first step further comprises the following steps:

3. The method for integrally and synchronously jacking and reconstructing the overpass according to claim 1, wherein the second step further comprises:

(1) excavating foundation earthwork of the bridge pier;

(2) roughening the surfaces of the pier column and the abutment foundation;

(3) anchoring the support anchor;

(4) constructing a bridge abutment foundation;

repairing the bridge abutment enlarged foundation by using concrete, and pouring along the transverse bridge direction; when concrete is poured, the original foundation is subjected to scabbling treatment, and the concrete is fully wetted by water.

4. The method for integrally and synchronously jacking and transforming the overpass according to claim 1, wherein the third step further comprises:

(1) arranging a steel support;

(2) a structural support system;

the main body of each pier column jacking support adopts a steel pipe as a support rod; flanges are welded at the upper end and the lower end of the steel pipe, and connecting components are welded on the side surfaces of the steel pipe; the lower part of each steel pipe support is connected with the column-embracing beam through an implantation or embedded anchor bolt;

(3) installing a steel support;

1) installing a steel support;

2) installing a steel cushion block;

(4) mounting a bridge bottom joist and a jack at the bridge abutment;

1) installing a distribution beam;

2) installing a jack;

when the jack is installed, the axis of the jack is ensured to be vertical;

the upper and lower parts of the jack are respectively provided with a steel base plate to disperse the concentrated force, so that the structure is not damaged;

5. The method for integrally and synchronously jacking and transforming the overpass according to claim 1, wherein the fourth step further comprises:

6. The method for integrally and synchronously jacking and transforming the overpass according to claim 1, wherein the step five further comprises the following steps:

configuring jacking control points and controlling areas;

before formal jacking, carrying out trial jacking;

after jacking is tried, if no problem exists, formal jacking is carried out;

7. The method for integrally and synchronously jacking and reconstructing the overpass according to claim 6, wherein the alternative jacking method comprises the following steps:

E. repeating the step C, D to repeatedly and alternately lift the bridge structure until the bridge structure is lifted to a preset height;

in the step C or D, the steel supporting cushion blocks which are overlapped and cushioned up and down are connected and fixed through connecting bolts;

8. The method for integrally and synchronously jacking and transforming the overpass according to claim 1, wherein the sixth step further comprises:

pier column connection;

constructing a bridge abutment;

(1) carrying out bar planting construction;

(2) carrying out bar planting construction;

the steel bars adopted by the steel bar planting are HRB335 steel bars;

9. The method for integrally and synchronously jacking and transforming the overpass according to claim 1, wherein a PLC (programmable logic controller) is adopted to control a variable frequency synchronous system to perform jacking construction;

the central controller (8) is respectively connected with each displacement sensor (2) through a sensing wire (7);

a variable frequency pump station (10) is arranged on the oil tank (11);

10. The method of claim 9, wherein the method comprises the steps of,

PLC control frequency conversion synchronous system still includes: a multipoint synchronous hydraulic control system;