1. A construction method for a turnout continuous beam of a grand bridge of an elevated station is characterized by comprising the following steps:

s1, construction of piers: sequentially performing pile foundation construction, steel sheet pile construction, bearing platform construction and pier body construction to form a pier;

s2, constructing the middle-section bridge:

s21, erecting a construction scaffold, wherein the construction scaffold sequentially comprises drilled piles or crown beams, steel pipe columns and Bailey beams from bottom to top;

s22, sequentially loading, unloading and pre-pressing the construction falsework according to 60%, 80%, 100% and 110% of construction load so as to eliminate inelastic deformation of the construction falsework and obtain elastic deformation data and foundation subsidence data of the construction falsework; the construction load is the sum of a concrete dead weight load, a template load, a crowd machine tool load and a wind load;

s23, erecting a segment template on the construction falsework, wherein the bottom die elevation of the segment template is obtained according to the elastic deformation data, the foundation subsidence data and the reserved camber;

s24, binding beam section steel bars corresponding to the section bridge; embedding reinforcing steel bars of a ballast retaining wall and pouring concrete into the reinforcing steel bars of the beam section; then carrying out prestress construction;

s3, synchronously constructing two end section beams positioned at two sides of the middle section bridge: repeating steps S21-S24 such that the middle section bridge, the two end section beams form a continuous beam; beam section steel bars corresponding to the middle section bridge and beam section steel bars corresponding to the end section beams are bound and connected by the steel bars in the reserved space due to tensioning and grouting to form binding section steel bars, and the binding section steel bars are located between the two piers;

s4, tensioning the continuous beam.

2. The construction method of the turnout continuous beam of the grand station grand bridge according to claim 1, wherein step S4 is followed by the further steps of:

s5, pouring concrete into the reinforcing steel bars of the ballast retaining wall to form the ballast retaining wall;

and S6, arranging a drain hole at the end part of the ballast retaining wall close to one side of the continuous beam, performing waterproof treatment on the drain hole, and enabling an inner protection layer of the cable trough to transit to the inner side of the ballast retaining wall along a slope.

3. The construction method of the turnout continuous beam of the grand station grand bridge according to claim 1, wherein step S4 is followed by the further steps of:

s7, removing the construction falsework;

and S8, bridge deck engineering construction.

4. The construction method of the turnout continuous beam of the grand station grand bridge according to claim 1, wherein step S1 is followed by the further steps of:

s9, constructing a permanent support; the permanent support comprises a plurality of longitudinal movable supports, a plurality of multidirectional movable supports, a fixed support and a transverse movable support, two permanent supports are arranged on each pier along the left and right directions respectively, one longitudinal movable support and one multidirectional movable support are arranged on one pier at the same time, the fixed support and the transverse movable support are arranged on one pier at the same time, two longitudinal movable supports are arranged on one pier at the same time, the longitudinal movable support and the fixed support are arranged at the same side, and the multidirectional movable support and the transverse movable support are arranged at the same side;

s91, calculating a support pre-deviation amount of each permanent support, wherein the support pre-deviation amount satisfies the formulas (1) and (2);

Δ＝-(Δ1+Δ2) (1)

Δ2＝α·Δt·L (2)

wherein, delta is the support pre-offset, and the permanent support deviates from the theoretical central line along the left and right direction; Δ 1 is the offset of the support point corresponding to the permanent support caused by the elastic deformation and the shrinkage creep of the continuous beam; delta 2 is the offset of the permanent support caused by the temperature difference of the system; alpha is the linear expansion coefficient of the concrete of the continuous beam; delta t is the closure temperature difference; l is the length of the beam from the temperature fixed point to the calculation point, namely the length of the beam between the permanent support and the fixed support;

and S92, mounting each permanent support to a corresponding pier according to the support pre-offset corresponding to the permanent support.

5. The construction method of the turnout continuous beam of the grand bridge of the elevated station according to any one of claims 1 to 4, characterized in that:

the continuous beam is a box beam which is symmetrical left and right and comprises a top plate, a bottom plate, a cantilever plate and a web plate which are integrally cast;

the top plate and the bottom plate are oppositely arranged along the height direction, the two webs are respectively arranged at two sides of the bottom plate along the left-right direction, so that the top plate, the bottom plate and the two webs jointly enclose a box chamber, and the two cantilever plates are respectively arranged at two sides of the top plate along the left-right direction; the lower end of the web plate is connected with the bottom plate, and the upper end of the web plate is connected with the joint of the top plate and the cantilever plate; the thickness of the top plate, the bottom plate, the cantilever plate and the web close to the joint is larger than that of the part far away from the joint; the web and the cantilever plate are in arc transition at the joint far away from one side of the box chamber, and the bottom plate and the web are in arc transition at the joint far away from one side of the box chamber.

6. The construction method of the turnout continuous beam of the grand station grand bridge according to claim 5, wherein the step of binding the beam section steel bar corresponding to the section bridge specifically comprises the steps of:

s241, binding bottom-layer steel bars of the bottom plate;

s242, installing a bottom plate bundle corrugated pipe corresponding to the bottom plate;

s243, binding the bottom plate top layer steel bars of the bottom plate;

s244, binding web steel bars of the web;

s245, mounting the web bundle corrugated pipes corresponding to the webs;

s246, binding the bottom layer steel bars of the top plate;

s247, installing top plate bundle corrugated pipes corresponding to the top plates, wherein the top plate bundle corrugated pipes extend along the left-right direction;

and S248, binding top steel bars of the top plate.

7. The construction method of the turnout continuous beam of the grand station grand bridge according to claim 5, wherein the step S23 specifically comprises the steps of:

s231, mounting a bottom die: obtaining the bottom die elevation of the bottom die according to the elastic deformation data, the foundation sinking data and the reserved camber; mounting the bottom die on the construction falsework according to the bottom die elevation;

s232, mounting a side die: hoisting the side die to the corresponding bottom die, adjusting the verticality of the side die by using a jacking, and connecting the side die with an end die;

s233, installing an inner die: a plurality of segment internal molds are manufactured in sections in advance, and are hoisted to preset positions of the construction falsework and are assembled to form a complete internal mold;

s234, installing the end die: the center line of the end die in the left-right direction is coincided with the center line of the bottom die in the left-right direction so as to ensure the height and the design verticality of the beam body of the continuous beam, and the end die is respectively connected with the side die and the bottom die;

s235, sealing the joints of the templates: and sealing the joints formed by the bottom die and the side die, the bottom die and the end die, the side die and the end die and the joints of the inner die which are mutually connected.

8. The construction method of the turnout continuous beam of the grand station grand bridge according to claim 7, characterized in that:

a support frame is arranged between the side die corresponding to the cantilever plate and the construction falsework;

and a lead screw which is obliquely arranged is arranged between the side die corresponding to the web and the construction falsework.

Background

With the rapid development of national economy of China, a traffic rapid passage of the four-way and eight-reach is established, and shortening the difference between the countries in China and even China is an important guarantee for accelerating the internal circulation and the external circulation of the economy of China.

Compared with the high cost of removal, diversion and the like caused by the fact that the traffic route is additionally arranged on the existing traffic route, the mode of directly erecting the viaduct to form the high-altitude traffic route is a fast, convenient and low-cost traffic network construction mode, but how to provide the turnout continuous beam construction method which is suitable for various terrains, convenient and fast to construct and high in engineering quality is a difficult problem to solve urgently by the technical personnel in the field.

Disclosure of Invention

Aiming at the defects or the improvement requirements of the prior art, the invention provides a construction method of a turnout continuous beam of an overhead station grand bridge.

The invention discloses a construction method of a turnout continuous beam of a grand bridge of an elevated station, which comprises the following steps:

s1, construction of piers: sequentially performing pile foundation construction, steel sheet pile construction, bearing platform construction and pier body construction to form a pier;

s2, constructing the middle-section bridge:

s21, erecting a construction scaffold, wherein the construction scaffold sequentially comprises drilled piles or crown beams, steel pipe columns and Bailey beams from bottom to top;

s22, sequentially loading, unloading and pre-pressing the construction falsework according to 60%, 80%, 100% and 110% of construction load so as to eliminate inelastic deformation of the construction falsework and obtain elastic deformation data and foundation subsidence data of the construction falsework; the construction load is the sum of a concrete dead weight load, a template load, a crowd machine tool load and a wind load;

s23, erecting a segment template on the construction falsework, wherein the bottom die elevation of the segment template is obtained according to the elastic deformation data, the foundation subsidence data and the reserved camber;

s24, binding beam section steel bars corresponding to the section bridge; embedding reinforcing steel bars of a ballast retaining wall and pouring concrete into the reinforcing steel bars of the beam section; then carrying out prestress construction;

s3, synchronously constructing two end section beams positioned at two sides of the middle section bridge: repeating steps S21-S24 such that the middle section bridge, the two end section beams form a continuous beam; beam section steel bars corresponding to the middle section bridge and beam section steel bars corresponding to the end section beams are bound and connected by the steel bars in the reserved space due to tensioning and grouting to form binding section steel bars, and the binding section steel bars are located between the two piers;

s4, tensioning the continuous beam.

Optionally, step S4 is followed by the step of:

s5, pouring concrete into the reinforcing steel bars of the ballast retaining wall to form the ballast retaining wall;

and S6, arranging a drain hole at the end part of the ballast retaining wall close to one side of the continuous beam, performing waterproof treatment on the drain hole, and enabling an inner protection layer of the cable trough to transit to the inner side of the ballast retaining wall along a slope.

Optionally, step S4 is followed by the step of:

s7, removing the construction falsework;

and S8, bridge deck engineering construction.

Optionally, step S1 is followed by the step of:

s9, constructing a permanent support; the permanent support comprises a plurality of longitudinal movable supports, a plurality of multidirectional movable supports, a fixed support and a transverse movable support, two permanent supports are arranged on each pier along the left and right directions respectively, one longitudinal movable support and one multidirectional movable support are arranged on one pier at the same time, the fixed support and the transverse movable support are arranged on one pier at the same time, two longitudinal movable supports are arranged on one pier at the same time, the longitudinal movable support and the fixed support are arranged at the same side, and the multidirectional movable support and the transverse movable support are arranged at the same side;

s91, calculating a support pre-deviation amount of each permanent support, wherein the support pre-deviation amount satisfies the formulas (1) and (2);

Δ＝-(Δ1+Δ2) (1)

Δ2＝α·Δt·L (2)

wherein, delta is the support pre-offset, and the permanent support deviates from the theoretical central line along the left and right direction; Δ 1 is the offset of the support point corresponding to the permanent support caused by the elastic deformation and the shrinkage creep of the continuous beam; delta 2 is the offset of the permanent support caused by the temperature difference of the system; alpha is the linear expansion coefficient of the concrete of the continuous beam; delta t is the closure temperature difference; l is the length of the beam from the temperature fixed point to the calculation point, namely the length of the beam between the permanent support and the fixed support;

and S92, mounting each permanent support to a corresponding pier according to the support pre-offset corresponding to the permanent support.

Optionally, the continuous beam is a box beam which is bilaterally symmetrical and comprises a top plate, a bottom plate, a cantilever plate and a web plate which are integrally cast; the top plate and the bottom plate are oppositely arranged along the height direction, the two webs are respectively arranged at two sides of the bottom plate along the left-right direction, so that the top plate, the bottom plate and the two webs jointly enclose a box chamber, and the two cantilever plates are respectively arranged at two sides of the top plate along the left-right direction; the lower end of the web plate is connected with the bottom plate, and the upper end of the web plate is connected with the joint of the top plate and the cantilever plate; the thickness of the top plate, the bottom plate, the cantilever plate and the web close to the joint is larger than that of the part far away from the joint; the web and the cantilever plate are in arc transition at the joint far away from one side of the box chamber, and the bottom plate and the web are in arc transition at the joint far away from one side of the box chamber.

Optionally, the step of binding the beam section steel bars corresponding to the section bridge specifically includes:

s241, binding bottom-layer steel bars of the bottom plate;

s242, installing a bottom plate bundle corrugated pipe corresponding to the bottom plate;

s243, binding the bottom plate top layer steel bars of the bottom plate;

s244, binding web steel bars of the web;

s245, mounting the web bundle corrugated pipes corresponding to the webs;

s246, binding the bottom layer steel bars of the top plate;

s247, installing top plate bundle corrugated pipes corresponding to the top plates, wherein the top plate bundle corrugated pipes extend along the left-right direction;

and S248, binding top steel bars of the top plate.

Optionally, the step S23 specifically includes the steps of:

s231, mounting a bottom die: obtaining the bottom die elevation of the bottom die according to the elastic deformation data, the foundation sinking data and the reserved camber; mounting the bottom die on the construction falsework according to the bottom die elevation;

s232, mounting a side die: hoisting the side die to the corresponding bottom die, adjusting the verticality of the side die by using a jacking, and connecting the side die with an end die;

s233, installing an inner die: a plurality of segment internal molds are manufactured in sections in advance, and are hoisted to preset positions of the construction falsework and are assembled to form a complete internal mold;

s234, installing the end die: the center line of the end die in the left-right direction is coincided with the center line of the bottom die in the left-right direction so as to ensure the height and the design verticality of the beam body of the continuous beam, and the end die is respectively connected with the side die and the bottom die;

s235, sealing the joints of the templates: and sealing the joints formed by the bottom die and the side die, the bottom die and the end die, the side die and the end die and the joints of the inner die which are mutually connected.

Optionally, a support frame is arranged between the side die corresponding to the cantilever plate and the construction falsework; and a lead screw which is obliquely arranged is arranged between the side die corresponding to the web and the construction falsework.

In general, compared with the prior art, the above technical solution contemplated by the present invention can achieve the following beneficial effects:

1. in the invention, the construction falsework adopting the bored pile, the crown beam, the steel pipe column and the Bailey beam has the advantages of quick construction period, large bearing capacity, good stability and capability of bearing a certain horizontal force, and meets the requirements of variable terrains (river crossing, boundary crossing, poor terrain condition, underground pipelines, poor geological condition, poor foundation bearing capacity and the like); preferably, the turnout continuous beam is pre-pressed by gradual loading and unloading, so that the safety of the turnout continuous beam is ensured, the inelastic deformation of the turnout continuous beam is eliminated, and the elastic deformation and foundation sinking data of the turnout continuous beam can be obtained, so that the bottom die elevation of the segmental template meets the actual construction working condition, and the integral structure and high engineering quality of the turnout continuous beam are ensured; preferably, the turnout continuous beam is formed by casting integrally, the structural strength is high, and the bearing performance and the service life of the turnout continuous beam are ensured; the construction of the middle section first and then the construction of the two end sections are respectively carried out, and finally the integral tensioning is carried out, so that the deformation performance and the structural strength of the turnout continuous beam are ensured, and the engineering quality of the turnout continuous beam is further improved.

2. According to the turnout continuous beam, the ballast retaining wall and the continuous beam are integrally cast, the integrity of the whole bridge and the structural strength of the ballast retaining wall are guaranteed, the shock resistance and the service life of the ballast retaining wall are improved, a reliable buffer belt is provided for external accidents, and the safety of the turnout continuous beam is improved. Preferably, the drainage holes are formed in the ballast blocking walls, so that water on the bridge floor can be reserved from two sides of the bridge floor along the gradient of the bridge floor, the phenomenon that water is accumulated and stored on the bridge floor is avoided, the dryness of the bridge floor is ensured, and adverse phenomena such as slipping, freezing and the like are avoided, so that the running safety of a vehicle is ensured; more preferably, the inner protection layer of the cable duct is transited to the inner side of the ballast blocking wall along the slope, so that the dryness and the safety of the cable duct are guaranteed, the accumulated water in the cable duct is avoided, and the safety performance of the turnout continuous beam is integrally improved.

3. In the invention, different types of permanent supports are arranged on corresponding piers to support the continuous beam, and the support pre-deviation of each permanent support is calculated, so that the permanent supports are adaptively arranged on the piers according to actual construction conditions, the permanent supports are arranged to meet the phenomena of swinging displacement and the like of the continuous beam in the actual use process, and the engineering quality of the whole turnout continuous beam is ensured.

Drawings

FIG. 1 is a schematic flow chart diagram of an embodiment of the present invention;

FIG. 2 is a schematic flow chart diagram of another embodiment of the present invention;

FIG. 3 is a schematic flow chart diagram of another embodiment of the present invention;

FIG. 4 is a flow chart illustrating another embodiment of the present invention;

FIG. 5 is a schematic illustration of a permanent support construction according to another embodiment of the present invention;

FIG. 6 is a schematic structural diagram of another embodiment of the present invention;

fig. 7 is a schematic cross-sectional view of fig. 6.

In all the figures, the same reference numerals denote the same features, in particular: 01-pier I, 02-pier II, 03-pier III, 04-pier IV, 05-pier V, 06-pier VI, 07-pier IV, 1-continuous beam, 11-middle section bridge, 12-first end section beam, 13-second end section beam, 2-construction falsework, 21-crown beam, 22-steel pipe column, 23-Bailey beam, 25-screw rod, 26-support frame, 27-scissor support frame, 28-protective shed frame, 29-bearing platform, 31-top plate, 32-bottom plate, 33-cantilever plate, 34-web plate, 35-box chamber, 41-bottom die, 42-side die, 43-inner die, 51-longitudinal movable support, 52-multidirectional movable support, 53-fixed support, 54-transverse cradle.

Detailed Description

In order to make the objects, technical solutions and advantages of the present invention more apparent, the present invention is described in further detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention. In addition, the technical features involved in the embodiments of the present invention described below may be combined with each other as long as they do not conflict with each other.

In one embodiment of the present invention, as shown in fig. 1, a construction method for a continuous beam of a turnout of an overpass in an elevated station comprises the following steps:

s1, construction of piers: sequentially performing pile foundation construction, steel sheet pile construction, bearing platform construction and pier body construction to form a pier;

s2, constructing the middle-section bridge 11:

s21, erecting a construction scaffold 2, wherein the construction scaffold 2 sequentially comprises drilled piles or crown beams 21, steel pipe columns 22 and Bailey beams 23 from bottom to top;

s22, sequentially loading and unloading prepressing the construction scaffold 2 according to 60%, 80%, 100% and 110% of the construction load to eliminate inelastic deformation of the construction scaffold 2, and obtain elastic deformation data and foundation subsidence data of the construction scaffold 2; the construction load is the sum of a concrete dead weight load, a template load, a crowd machine tool load and a wind load;

s23, erecting a segment template on the construction scaffold 2, wherein the bottom die 41 elevation of the segment template is obtained according to the elastic deformation data, the foundation subsidence data and the reserved camber;

s24, binding beam section steel bars corresponding to the section bridge; embedding reinforcing steel bars of a ballast retaining wall and pouring concrete into the reinforcing steel bars of the beam section; then carrying out prestress construction;

s3, synchronously constructing two end section beams positioned at two sides of the middle section bridge 11: repeating steps S21-S24 so that the middle section bridge 11, the two end section beams form a continuous beam 1; beam section steel bars corresponding to the middle section bridge 11 and beam section steel bars corresponding to the end section beams are bound and connected by the steel bars in the reserved space due to tensioning and grouting to form binding section steel bars, and the binding section steel bars are located between the two piers;

and S4, tensioning the continuous beam 1.

It should be noted that, in this embodiment, in order to ensure the engineering quality of the turnout continuous beam, the construction of the pier is a key technology, and therefore, step S1 specifically includes the steps of: pile foundation construction, equal strength, steel sheet pile construction, pile cap excavation, cushion layer and pile detection, pile cap construction, pile cap concrete pouring, equal strength and pier body construction. And the construction process of the pier body is pre-embedded with the cushion stone reinforcing steel bars corresponding to the support cushion stones for supporting the following permanent supports, concrete of the support cushion stones is separately poured with concrete corresponding to the pier body, and the support cushion stones are required to bear great support pressure in the later period, so that support meshes and concrete are strictly constructed according to drawings, the support cushion stones are C50 concrete and are separately poured with the pier body concrete, and the pre-embedding of the pier body reinforcing steel bars is required during the construction of the pier body. And reserve the support bolt hole when pier shaft and support seat cushion stone construction, the accurate lofting of size that bolt hole position, degree of depth provided according to the support description sets up the preformed hole, and chiseling and sanitization will the preformed hole when the support is installed adopts the mortar anchor support bolt that excels in. Before the permanent support is installed, the levelness and the height difference of four corners of the top surface of the support base cushion are checked by using a level gauge and a level ruler, and when exceeding standards, the support base cushion is manually chiseled, polished and leveled. Before the permanent support is installed, a cross line is popped out from the top of the cushion stone to control the plane position and the direction of the support. The permanent support of the turnout continuous beam is preferably constructed by adopting a gravity grouting method.

In practical application, part of the bored piles of the construction scaffold 2 are set on the foundation, part of the bored piles are set on the cap 29, and the beret beam 23 is used for in-situ cast-in-place construction in step S21. The construction falsework 2 comprises a crown beam 21 (or a drilled pile connected with a bearing platform 29) connected with a foundation, a steel pipe column 22, double-spliced I-shaped steel, a Bailey beam 23, a bottom die distribution beam framework, square timbers, a bottom die 41, side dies 42, supports and the like from bottom to top, wherein the bottom die 41 and the supportsThe side mold 42 is preferably made of bamboo plywood, and the inner mold 43 is made of plate material. And the top of each steel pipe column 22 is provided with a sand box, so that the construction scaffold 2 and the segment template can be conveniently detached, namely, the double-spliced I-shaped steel is supported on the sand box. The lower end of each steel pipe column 22 is spot-welded and connected with a steel plate with the thickness of 20mm and the thickness of 90 multiplied by 90cm, so that the contact area between the steel pipe column 22 and the bearing platform 29 (the crown beam 21) is increased; the joint of the steel plate and the end of the steel pipe is reinforced by a small triangular steel plate with the thickness of 8mm and the thickness of 10cm multiplied by 10 cm; the steel pipe column 22 is provided with a protective shed frame 28. Mounted on the platform 29 and the crown beam 21The steel pipe columns 22 (the parts are 609 multiplied by 16mm), each row is 4, the distance is 2.8m +3m +2.8m, the steel pipe columns 22 arranged in the left-right direction (namely the transverse direction) and between the adjacent steel pipe columns are reinforced and connected through a scissor support frame 27, so that the structural strength and the bearing performance of the construction falsework 2 are improved, 2I56b I-steel transverse distribution beams are arranged on the steel pipe columns 22, and then the longitudinal Bailey beams 23 are distributed. Due to construction needs, the construction scaffold 2 and the segment formwork corresponding to the middle-section bridge 11 are erected firstly, and after the construction scaffold 2 and the segment formwork corresponding to the middle-section bridge 11 are completed, the construction scaffold 2 and the segment formwork corresponding to the two end-section beams (i.e. the first end-section beam 12 and the second end-section beam 13) are erected.

The self-weight load of the concrete in the step S22 can be obtained according to data provided by a design drawing, the weight of the diaphragm plate on each pier is born by the pier top, and the weight of the diaphragm plate can be selectively removed or not removed when the construction scaffold 2 is calculated. The template load and the crowd machine load can be calculated and obtained according to the design drawing and the construction drawing, and the wind load can be obtained according to the design drawing and the wind load of the local construction. The pre-pressing is carried out by stacking pre-pressed materials. Specifically, in the pre-pressing loading process, the pre-pressing loading is divided into four stages of loading according to 60%, 80%, 100% and 110% of construction load. And obtaining an initial value by observation once before loading. And standing for 1h after each stage of loading to measure vertical and transverse deformation values. And in the prepressing process, the project measuring team tracks in the whole process. Before prepressing, the measurement team lays points according to a scheme and collects original data. When the difference between the last two observed deformation values after the loading is carried out to 110% is less than 2mm, the support deformation can be determined to be stable, and the measurement can be stopped. In the whole measuring process, when the measured data is found to have large change, the prepressing is stopped, the observation is continued, the reason is analyzed, and the safety of the support is ensured. In the process of pre-pressing and unloading, unloading to 100% of the designed load, holding the load for 60min, measuring the elevation and the displacement and recording; unloading to 80% of the designed load, holding the load for 60min, measuring the elevation and the displacement and recording; unloading to 60% of the designed load, holding the load for 60min, measuring the elevation and the displacement and recording; and (5) completely unloading, standing for 60min, measuring the elevation and the displacement and recording.

In the work progress, can reserve the headspace of prestressing force construction between middle section bridge 11 and the end section roof beam, consequently, after middle section bridge 11 construction, need carry out the ligature with the reinforcing bar that middle section bridge 11 is located the headspace and the reinforcing bar that the end section roof beam is located the headspace to guarantee continuous beam 1's integrated into one piece, and then guarantee continuous beam 1's overall structure intensity.

In another embodiment of the present invention, on the basis of the above embodiment, the step S4 is further followed by the step of:

s5, pouring concrete into the reinforcing steel bars of the ballast retaining wall to form the ballast retaining wall;

and S6, arranging a drain hole at the end part of the ballast retaining wall close to one side of the continuous beam 1, performing waterproof treatment on the drain hole, and enabling an inner protection layer of the cable trough to transit to the inner side of the ballast retaining wall along a slope.

In another embodiment of the present invention, on the basis of any of the above embodiments, the method further includes, after step S4, the step of:

s7, removing the construction scaffold 2;

and S8, bridge deck engineering construction.

In another embodiment of the present invention, on the basis of any of the above embodiments, the method further includes, after step S1, the step of:

s9, constructing a permanent support; the permanent support comprises a plurality of longitudinal movable supports 51, a plurality of multidirectional movable supports 52, a fixed support 53 and a transverse movable support 54, two permanent supports are respectively arranged on each pier along the left and right direction, the longitudinal movable support 51 and the multidirectional movable support 52 are simultaneously arranged on one pier, the fixed support 53 and the transverse movable support 54 are simultaneously arranged on one pier, the two longitudinal movable supports 51 are simultaneously arranged on one pier, the longitudinal movable support 51 and the fixed support 53 are arranged on the same side, and the multidirectional movable support 52 and the transverse movable support 54 are arranged on the same side;

s91, calculating a support pre-deviation amount of each permanent support, wherein the support pre-deviation amount satisfies the formulas (1) and (2);

Δ＝-(Δ1+Δ2) (1)

Δ2＝α*Δt*L (2)

wherein, delta is the support pre-offset, and the permanent support deviates from the theoretical central line along the left and right direction (namely the longitudinal direction); Δ 1 is the offset at the fulcrum corresponding to the permanent support caused by the elastic deformation and the shrinkage creep of the continuous beam 1; delta 2 is the offset of the permanent support caused by the temperature difference of the system; alpha is the linear expansion coefficient of the concrete of the continuous beam 1; delta t is the closure temperature difference; l is the beam length from the temperature fixed point to the calculation point, i.e. the beam length between the permanent support and the fixed support 53;

and S92, mounting each permanent support to a corresponding pier according to the support pre-offset corresponding to the permanent support.

Specifically, as shown in fig. 4 and 5, for example, the continuous beam 1 corresponds to seven piers sequentially arranged at intervals along the bridge length direction (i.e., the longitudinal direction) and includes a first pier 01, a second pier 02, a third pier 03, a fourth pier 04, a fifth pier 05, a sixth pier 06 and a seventh pier 07, wherein the first pier 01, the second pier 02, the third pier 03 and the fourth pier 04 are all provided with one of the longitudinally movable supports 51 and one of the multi-directional movable supports 52; a fixed support 53 and the transverse movable support 54 are arranged on the fifth pier 05; the six bridge piers 06 and the seven bridge piers 07 are respectively provided with two longitudinal movable supports 51; in this embodiment, the fixed support 53 is used as a calculation point, and different permanent supports are used as temperature fixed points. The distance between the first pier 01 and the second pier 02 is 32.35m (the distance between the two corresponding permanent supports is 31.6m), the distance between the second pier 02 and the third pier 03, the distance between the third pier 03 and the fourth pier 04, the distance between the fourth pier 04 and the fifth pier 05 is 32.7m (the distance between the two corresponding permanent supports is 32.70m), the distance between the fifth pier 05 and the sixth pier 06 is 48m (the distance between the two corresponding permanent supports is 48m), and the distance between the sixth pier 06 and the seventh pier 07 is 32.35m (the distance between the two corresponding permanent supports is 31.6 m).

Δ 1 can be obtained from the design drawing, which gives the longitudinal pre-offset (theoretical value) for each permanent support, where α is 1 × 10^-5Considering the temperature of 15 ℃, the lowest temperature of the past year is 10 ℃, and the offset delta 2 caused by the temperature difference is as follows:

a first bridge pier 01: Δ 2 ═ α ═ Δ t ═ L ═ 1 × 10^-5×(10-15)×129.7＝-0.006m

And a second pier 02: Δ 2 ═ α ═ Δ t ═ L ═ 1 × 10^-5×(10-15)×98.1＝-0.005m

A pier III 03: Δ 2 ═ α ═ Δ t ═ L ═ 1 × 10^-5×(10-15)×65.4＝-0.003m

Pier four 04: Δ 2 ═ α ═ Δ t ═ L ═ 1 × 10^-5×(10-15)×32.7＝-0.002m

Six bridge piers 06: Δ 2 ═ α ═ Δ t ═ L ═ 1 × 10^-5×(10-15)×48＝-0.002m

Seven 07 parts of bridge pier: Δ 2 ═ α ═ Δ t ═ L ═ 1 × 10^-5×(10-15)×79.6＝-0.004m

The pre-offset Δ of the support can be obtained by combining the formula (1), and the table 1 can be referred to specifically. The pre-eccentric directions are both directions away from the fixed support 53.

Table 132.35 +3 x 32.7+48+32.35m switch continuous beam support pre-deviation table

In another embodiment of the present invention, based on any of the above embodiments, as shown in fig. 2 to 7, the continuous beam 1 is a box beam with bilateral symmetry, and includes a top plate 31, a bottom plate 32, a cantilever plate 33 and a web plate 34 which are integrally cast; the top plate 31 and the bottom plate 32 are oppositely arranged along the height direction, the two webs 34 are respectively arranged at two sides of the bottom plate 32 along the left-right direction, so that the top plate 31, the bottom plate 32 and the two webs 34 jointly enclose a box chamber 35, and the two cantilever plates 33 are respectively arranged at two sides of the top plate 31 along the left-right direction; the lower end of the web 34 is connected with the bottom plate 32, and the upper end of the web 34 is connected with the joint of the top plate 31 and the cantilever plate 33; the thickness of the top plate 31, the bottom plate 32, the cantilever plate 33 and the web 34 close to the joint is larger than that of the part far away from the joint; the connecting part of the web 34 and the cantilever plate 33 far away from the box chamber 35 is in arc transition, and the connecting part of the bottom plate 32 and the web 34 far away from the box chamber 35 is in arc transition.

Optionally, the step of binding the beam section steel bars corresponding to the section bridge specifically includes:

s241, binding bottom layer steel bars of the bottom plate 32;

s242, installing a bottom plate bundle corrugated pipe corresponding to the bottom plate 32;

s243, binding the bottom plate top layer steel bars of the bottom plate 32;

s244, binding the web steel bars of the web 34;

s245, mounting the web bundle corrugated pipe corresponding to the web 34;

s246, binding the bottom layer steel bars of the top plate 31;

s247, installing a top plate bundle corrugated pipe corresponding to the top plate 31, wherein the top plate bundle corrugated pipe extends along the left-right direction;

and S248, binding the top steel bars of the top plate 31.

Specifically, before the bottom plate steel bar is bound, the positions of the longitudinal and transverse steel bars are marked on the pedestal according to the designed steel bar spacing. Then the bottom layer longitudinal and transverse steel bars are sequentially placed, and binding is carried out after the positions of the steel bars are adjusted. The binding points are arranged according to a quincunx shape. After the bottom layer binding is finished, 4 pieces/m are arranged in length and breadth²The concrete cushion block is arranged under the bottom layer steel bar of the bottom plate. And installing the bottom plate bundle corrugated pipe according to the coordinates of the bottom plate bundle pore passage. Welding a supporting rib on the steel bar at each cushion block according to the steel bars on the upper layer and the lower layerAnd (4) spacing, welding longitudinal and transverse steel bars on the supporting ribs to serve as supporting and binding steel bars on the top layer of the bottom plate. And after the top steel bars of the bottom plate are bound, binding the tooth block steel bars of the bottom plate.

The web stirrups are placed in sequence according to the position marked on the base plate 32. Firstly, binding the outside longitudinal distribution ribs in the stirrups, and installing clamping type concrete cushion blocks on the stirrups at intervals of 1 m. The web bundle corrugated pipe is installed, the sealing work of the joint of the web bundle corrugated pipe and the anchor backing plate is paid attention to the plastic adhesive tape, and slurry leakage during concrete pouring is prevented.

The positioning net should be encrypted at the bent part of the pipeline to ensure the correct position of the pipeline. The lap length of the ends of the sections of the reinforcing steel bars extending out of the beam section meets the design requirement, and the joint connection of the sections of the reinforcing steel bars is lapped according to lap welding. When the position of the steel bar is inconsistent with the position of the prestressed pipeline, the position of the prestressed pipeline is accurate, and when the difference is more, the position of the prestressed pipeline can not be moved freely, and the position of the prestressed pipeline can not be solved by research of design units and supervision engineers.

The case roof beam adopts vertical prestressing force system, and the pipeline is by the pore-forming of galvanized bellows, and the bellows is that the steel band spiral is folded and form, therefore the piping erection should cup joint in the same direction of wearing to restraint, and the ripple direction is unanimous with wearing to restraint the direction, and the bellows extension adopts the bellows of big one to cup joint, cup joints length about 50cm, and every 0.5m establishes a fixed muscle in the roof beam section, fixed pipeline position, and pipeline positioning error should be less than 1 mm.

The spacing lines of the reinforcing steel bars are drawn at the top of the inner die 43 according to the designed reinforcing steel bar spacing before the reinforcing steel bars at the bottom layer of the top plate are bound. And then binding according to the designed position and the designed interval, firstly binding the reinforcing steel bars of the tooth blocks of the top plate, binding the reinforcing steel bars in a reinforcing steel bar processing factory, and integrally hoisting the reinforcing steel bars to the corresponding templates. After the tying is completed, a concrete cushion block is laid on the bottom of the reinforcing steel bars.

The construction method for installing the top plate longitudinal prestress bundle corrugated pipe is the same as that of the web plate bundle.

In order to prevent the corrugated pipe joint from leaking slurry to block a pore passage in the concrete construction process, before the concrete construction, a plastic pipe with the inner diameter being 5mm smaller than that of each corrugated pipe (a bottom plate bundle corrugated pipe, a web plate bundle corrugated pipe and a top plate bundle corrugated pipe) is inserted into each corrugated pipe, and the plastic pipe extends into a reserved pore passage of the previous beam section to be not less than 1 m. And (3) timely drawing the plastic pipe in the concrete construction process, and timely flushing the pore channel after concrete pouring is finished if a slurry leakage phenomenon is found.

In another embodiment of the present invention, as shown in fig. 3 to 7, on the basis of the above embodiments, the step S23 specifically includes the steps of:

s231, mounting the bottom die 41: obtaining the bottom die elevation of the bottom die 41 according to the elastic deformation data, the foundation sinking data and the reserved camber; mounting the bottom die 41 on the construction falsework 2 according to the bottom die elevation;

s232, mounting the side mold 42: hoisting the side die 42 to the corresponding bottom die 41, adjusting the verticality of the side die 42 by using a jacking, and connecting the side die 42 with an end die;

s233, mounting the inner mold 43: a plurality of segment internal molds are manufactured in sections in advance, and are hoisted to preset positions of the construction falsework 2 and are spliced to form a complete internal mold 43;

s234, installing the end die: the center line of the end mould along the left-right direction is coincided with the center line of the bottom mould 41 along the left-right direction so as to ensure the beam height and the design verticality of the continuous beam 1, and the end mould is respectively connected with the side mould 42 and the bottom mould 41;

s235, sealing the joints of the templates: the bottom mold 41 and the side mold 42, the bottom mold 41 and the end mold, the side mold 42 and the end mold, and the inner mold 43, which are coupled to each other, are sealed.

Optionally, a support frame 26 is arranged between the side mould 42 corresponding to the cantilever plate 33 and the construction falsework 2; and lead screws 25 which are obliquely arranged are arranged between the side dies 42 corresponding to the web plates 34 and the construction scaffold 2.

Specifically, the bottom die 41 and the side die 42 are formed by combining a support frame 26, a screw rod 25 and a double-spliced bolting channel steel, and the support frame 26 is erected after the construction scaffold 2 is pre-pressed.

12cm of double-spliced bolted channel steel is installed on the Bailey beam 23 to serve as a bottom die distribution beam, 10cm square timbers are laid on the distribution beam, and then 1.5cm of bamboo plywood is laid on the square timbers to serve as a bottom die 41.

Three adjustable screw rods 25 are arranged at the position of the web plate 34 for auxiliary support, 2 channel steels are arranged on the inner side of each screw rod 25 to serve as an outer side die distribution beam, and square wood and bamboo plywood are arranged on the inner side of each distribution beam to form a side die 42.

The lower part of the flange plate adopts a supporting frame 26 consisting of a plate buckle support, the upright stanchion adopts a galvanized steel pipe with the diameter of 60mm and the wall thickness of 3.25mm, a cross rod and an inclined rod which are matched with the upright stanchion, an adjustable base of the upright stanchion and an adjustable jacking of the upright stanchion are used, 2 channel steels are installed above the jacking to be used as side mold distribution beams, and square wood and bamboo plywood are arranged above the distribution beams.

It will be understood by those skilled in the art that the foregoing is only a preferred embodiment of the present invention, and is not intended to limit the invention, and that any modification, equivalent replacement, or improvement made within the spirit and principle of the present invention should be included in the scope of the present invention.