Design method, perfusion system and perfusion method of concrete perfusion system for long-span arch bridge

Abstract

The present invention relates to the technical field of long-span arch bridge pipe concrete pouring, and in particular to a design method, a pouring system and a pouring method for a long-span arch bridge pipe concrete pouring system. The design method determines the number of segments of a single main chord pipe based on the initial setting time of concrete and the time required to fill half of the main chord pipe, and determines the number of grades for each main chord pipe based on the time for maintaining the best working performance of concrete and the time required to fill a section of the main chord pipe. When pouring at each level, the concrete in the main chord pipe is at the best working performance, which improves the pouring quality at each level and is beneficial to improving the overall pouring quality. At the same time, the pouring system scientifically determines the number of segments and the number of grades, so that the number of segments and the number of grades are combined with actual construction and are more accurate. This is beneficial to accurately determining the number and position of partition plates and slurry inlet pipes, effectively avoiding accidents such as pipe blockage and pipe burst caused by inaccurate segmentation and grading of the pouring system, and is beneficial to ensuring the construction period, construction safety and pouring quality.

Description

Technical Field

[0001] The present invention relates to the technical field of long-span arch bridge pipe concrete pouring, and in particular to a design method, a pouring system and a pouring method for a long-span arch bridge pipe concrete pouring system. Background Art

[0002] Pouring concrete inside the tube is a key process in the construction of steel tube concrete arch bridges. The pouring construction mostly adopts the jacking method. As the span and height of steel tube concrete arch bridges become larger and larger, the construction difficulty of concrete inside the tube of steel tube arch bridges increases. For large-span arch bridges with arch rib spans of more than 445m, the single pouring volume is large. If the construction method of pouring to the top in one time is adopted, the risk of pipe blockage is extremely high. Once pipe blockage occurs, it is bound to seriously affect the quality of the concrete inside the tube, bring subsequent processing difficulties, affect the forming quality of the large-span arch bridge, and lead to pouring failure. Therefore, for the construction of concrete inside the tube of large-span arch bridges, the existing technology proposes a graded and segmented pouring construction method for the main chord tube.

[0003] However, at present, the graded and segmented pouring of concrete in the arch bridge tube is often designed and constructed in a graded and segmented manner based on experience. For example, Chinese invention patent application CN108708264A discloses a graded construction method for concrete pouring of a large-span steel tube concrete arch bridge. The graded and segmented pouring length of the arch rib in this method is empirically determined based on the steel tube diameter, height, concrete properties and pumping power in the specific project, and a scientific graded and segmented model has not been formed. The inaccuracy of the graded and segmented pouring length directly affects the arrangement of components such as the slurry inlet pipe, slurry outlet pipe, slurry discharge pipe, and exhaust pipe, and affects the structure of the pouring system. Accidents such as pipe blockage and pipe burst are prone to occur due to factors such as concrete properties, pump pipe arrangement, and pumping pressure. This problem is particularly prominent for large-span arch bridges, which has an adverse impact on construction period, construction safety, and pouring quality.

[0004] Therefore, there is an urgent need for a technical solution to solve the technical problem that the existing large-span arch bridge in-pipe concrete pouring system is inaccurately graded and segmented, affecting the pouring system structure and adversely affecting the construction period, construction safety and pouring quality. Summary of the Invention

[0005] The purpose of the present invention is to provide a design method, a pouring system and a pouring method for a large-span arch bridge pipe concrete pouring system to address the technical problem that the existing large-span arch bridge pipe concrete pouring system has inaccurate grading and segmentation, which affects the structure of the pouring system and has an adverse effect on the construction period, construction safety and pouring quality.

[0006] In order to achieve the above object, the technical solution adopted by the present invention is:

[0007] A design method for a pipe concrete pouring system for a large-span arch bridge includes the steps of determining the number of segments of a single main chord pipe based on the initial setting time t1 of concrete and the time T1 required to fill half of the main chord pipe; determining the number of grades for each section of the main chord pipe based on the time t2 for maintaining the best working performance of concrete and the time T2 required to fill a section of the main chord pipe; determining the location and number of partition plates based on the segmentation results; and determining the number of slurry inlet pipes based on the grading results.

[0008] The design method of the large-span arch bridge pipe concrete pouring system of the present invention determines the number of segments of a single main chord pipe based on the initial setting time of concrete and the time required to fill half of the main chord pipe, and based on the general symmetrical pouring characteristics of large-span arch bridges, ensures that the concrete in the main chord pipe can maintain good plasticity before filling half of the main chord pipe, which is conducive to pumping and avoids the risk of pipe blockage; at the same time, based on the maintenance time of the optimal working performance of concrete and the time required to fill a section of the main chord pipe, the number of grades of each main chord pipe is determined, and the concrete pouring in the main chord pipe is completed in a graded manner, so that the concrete in the main chord pipe is at the optimal working performance during the pouring at each level, the pouring quality of each level is improved, and the overall pouring quality is improved; at the same time, the number of segments and the number of grades are scientifically determined, so that the number of segments and the number of grades are combined with the actual construction, which is more accurate; it is conducive to accurately determining the number and position of the partition plates and the slurry inlet pipes, effectively avoiding accidents such as pipe blockage and pipe burst caused by inaccurate segmentation and grading of the pouring system, and is conducive to ensuring the construction period, construction safety and pouring quality.

[0009] As a preferred embodiment of the present invention, when t1≥T1, a single main chord is divided into two sections by a dome partition plate; otherwise, each half main chord is divided into n sections by a chord partition plate, where n is a positive integer obtained by rounding up the ratio T1 / t1; when t2≥T2, the main chord of this section is not graded; otherwise, the main chord of this section is divided into m levels, where m is a positive integer obtained by rounding up the ratio T2 / t2, and a slurry inlet pipe is provided at each level.

[0010] As a preferred embodiment of the present invention, T1=πd 2 L / 8v, where: d is the radius of the main chord; L is the arc length of a single main chord; v is the pouring speed; T2=πd 2 L n / 4v, where: d is the radius of the main chord tube; L n is the arc length of the main chord tube; v is the injection speed.

[0011] As a preferred embodiment of the present invention, the optimal working performance maintenance time t2 of the concrete is obtained through a trial mixing test. The trial mixing test comprises: loading the concrete produced by the mixing plant into a tank truck, continuously rotating the mixing drum, taking concrete every half hour for working performance testing and drawing a curve, and t2 is the time of the changing point at which the curve drops sharply.

[0012] As a preferred embodiment of the present invention, the number of segments is determined based on the pumping pressure σ. When σ is less than 18 MPa, a single main chord is divided into two segments by the vault partition. Otherwise, each half of the main chord is divided into at least two segments. By comprehensively considering the initial setting time of concrete and the pumping pressure, the grading and segmentation results are more scientific and accurate, thus integrating theory with practice to ensure construction time, construction safety, and pouring quality.

[0013] As a preferred embodiment of the present invention, the pumping pressure σ = σ1 + σ2, where σ1 is the pump pipe resistance; σ2 is the concrete pressure in the main chord pipe. σ1 is calculated using industry standards, and σ2 = ρgh, where ρ is the concrete density, g is the acceleration of gravity, and h is the height difference between the concrete surface in the pipe and the pump outlet.

[0014] As a preferred embodiment of the present invention, the pumping pressure σ is estimated through a pump test.

[0015] The large-span arch bridge pipe concrete pouring system comprises a main chord pipe, and the main chord pipe is graded and segmented according to the design method of the large-span arch bridge pipe concrete pouring system.

[0016] The grouting system of the present invention accurately determines the number and position of partition plates and slurry inlet pipes based on the accurate number of segments and grades, so that the grouting system structure is combined with the pumping process, effectively avoiding accidents such as pipe blockage and pipe burst caused by concrete properties, pump pipe layout, pumping pressure, etc., which is conducive to ensuring construction period, construction safety and grouting quality.

[0017] As a preferred solution of the present invention, a slurry inlet pipe, an air extraction pipe, a slurry outlet pipe, a slag discharge pipe and an exhaust pipe are arranged on the main chord pipe according to the results of grading and segmentation, and an arch construction platform is arranged on the main chord pipe.

[0018] The pouring method of the large-span arch bridge pipe concrete pouring system adopts the construction sequence of first inner chord pipe and then outer chord pipe, first lower chord pipe and then upper chord pipe, and symmetrical pouring on both sides according to the position of the main chord pipe. It adopts a pumping process combined with vacuum system assistance and staged pressure injection.

[0019] The pouring method of the large-span arch bridge pipe concrete pouring system of the present invention makes the hierarchical and segmented structure division of the pouring system more accurate on the basis of scientifically designing the number of rings and segments of the main chord pipe, provides a favorable structural foundation for the pouring process, enables the pouring process to proceed smoothly, is conducive to improving the pouring quality, and ensures the construction period and construction safety.

[0020] In summary, due to the adoption of the above technical solution, the design method of the long-span arch bridge pipe concrete pouring system of the present invention has the following beneficial effects:

[0021] 1. The number of sections for a single main chord is determined based on the initial setting time of concrete and the time required to fill half the main chord. Considering the generally symmetrical pouring characteristics of long-span arch bridges, ensure that the concrete in the main chord maintains good plasticity before filling half the main chord, facilitating pumping and avoiding the risk of pipe blockage.

[0022] 2. The number of grades for each section of the main chord is determined based on the duration of the concrete's optimal working performance and the time required to fill a section of the main chord. The concrete pouring in the main chord is completed in stages, ensuring that the concrete in the main chord is at its optimal working performance during each stage of pouring. This improves the pouring quality at each stage and contributes to the overall improvement of the pouring quality.

[0023] 3. Scientifically determine the number of sections and grades, so that the number of sections and grades can be combined with the actual construction, which is more accurate;

[0024] 4. It is helpful to accurately determine the number and position of partition plates and slurry inlet pipes, effectively avoid accidents such as pipe blockage and pipe burst caused by inaccurate segmentation and grading of the grouting system, and is conducive to ensuring construction period, construction safety and grouting quality.

[0025] The beneficial effects of the long-span arch bridge pipe concrete pouring system of the present invention are:

[0026] According to the accurate number of sections and grades, the number and position of partition plates and slurry inlet pipes are determined, so that the grouting system structure is combined with the pumping process, effectively avoiding accidents such as pipe blockage and pipe burst caused by concrete properties, pump pipe layout, pumping pressure, etc., which is conducive to ensuring construction period, construction safety and grouting quality.

[0027] The beneficial effects of the pouring method of the large-span arch bridge pipe concrete pouring system of the present invention are:

[0028] On the basis of scientifically designing the number of rings and segments of the main chord, the hierarchical and segmented structure division of the grouting system is made more accurate, which provides a favorable structural foundation for the grouting process, enables the grouting process to proceed smoothly, and is conducive to improving the grouting quality and ensuring the construction period and construction safety. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1 This is a schematic diagram of the segmented structure of a single main chord tube (divided into two sections);

[0030] Figure 2 This is a schematic diagram of the segmented structure of a single main chord tube (divided into four sections);

[0031] Figure 3 This is a schematic diagram of the segmented structure of a single main chord tube (divided into six sections);

[0032] Figure 4 This is a schematic diagram of the segmented structure of a single main chord tube (divided into eight sections);

[0033] Figure 5 This is a schematic diagram of the hierarchical structure of a single-section main chord pipe (level one);

[0034] Figure 6 This is a schematic diagram of the hierarchical structure of a single-section main chord (secondary);

[0035] Figure 7 This is a schematic diagram of the hierarchical structure of a single-section main chord (three levels);

[0036] Figure 8 This is a schematic diagram of the hierarchical structure of a single-section main chord (four levels);

[0037] Figure 9 2. It is a structural diagram of a large-span arch bridge pipe concrete pouring system according to Example 3;

[0038] Figure 10 1. It is a schematic diagram of the pouring sequence of the pouring method of the large-span arch bridge pipe concrete pouring system of Example 4;

[0039] Figure 11 is a structural diagram of a large-span arch bridge pipe concrete pouring system corresponding to S1 in Example 4;

[0040] Figure 12 Schematic diagram of the structure of the large-span arch bridge pipe concrete pouring system corresponding to S2 in Example 4;

[0041] Figure 13 Schematic diagram of the structure of the large-span arch bridge pipe concrete pouring system corresponding to S3 in Example 4;

[0042] Figure 14 4 is a schematic structural diagram of a large-span arch bridge pipe concrete pouring system corresponding to S4 in Example 4;

[0043] Figure 15 It is a structural diagram of the large-span arch bridge pipe concrete pouring system corresponding to S5 in Example 4.

[0044] icon:

[0045] 1-main chord pipe, 2-partition plate, 21-arch partition plate, 22-chord pipe partition plate, 23-stiffening rib, 3-slurry inlet pipe, 4-exhaust pipe, 5-slurry outlet pipe, 6-slag discharge pipe, 7-exhaust pipe, 8-arch construction platform, 9-pump. DETAILED DESCRIPTION

[0046] The present invention will be described in detail below with reference to the accompanying drawings.

[0047] In order to make the purpose, technical solutions and advantages of the present invention more clearly understood, the present invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not intended to limit the present invention.

[0048] Example 1

[0049] The design method of the pipe concrete pouring system for a large-span arch bridge is as follows: first, the number of sections of a single main chord pipe 1 is determined based on the initial setting time t1 of the concrete and the time T1 required to fill half of the main chord pipe 1. The setting position and number of the partition plates 2 can be determined according to the number of sections; then, the number of grades of each section of the main chord pipe 1 is determined based on the maintenance time t2 of the optimal working performance of the concrete and the time T2 required to fill a section of the main chord pipe 1. The setting number of the slurry inlet pipes 3 can be determined according to the number of grades.

[0050] The design method of the large-span arch bridge pipe concrete pouring system of this embodiment determines the number of segments of a single main chord pipe 1 in combination with the initial setting time of concrete and the time required to fill half of the main chord pipe 1. In combination with the characteristics of symmetrical pouring of large-span arch bridges, when the pouring time of half of the main chord pipe 1 exceeds the initial setting time t1 of concrete, it is necessary to segment it so that the concrete pouring time of each segment is less than the initial setting time t1 of concrete, ensuring that the concrete in the main chord pipe 1 can maintain good plasticity before filling half of the main chord pipe 1, which is conducive to pumping and avoids the risk of pipe blockage; at the same time, in combination with the time to maintain the best working performance of concrete and the time to fill half of the main chord pipe 1, ... The time required for the segmented main chord pipe 1 determines the number of grades for each segment of the main chord pipe 1, and the concrete pouring in the main chord pipe 1 is completed in stages, so that the concrete in the main chord pipe 1 is at the best working performance during the pouring at each stage, improving the pouring quality at each stage, and benefiting the improvement of the overall pouring quality; at the same time, the number of segments and the number of grades are scientifically determined, so that the number of segments and the number of grades are combined with the actual construction, which is more accurate; it is beneficial to accurately determine the number and position of the partition plates 2 and the slurry inlet pipes 3, and effectively avoid accidents such as pipe blockage and pipe burst caused by inaccurate segmentation and grading of the pouring system, which is beneficial to ensuring the construction period, construction safety and pouring quality.

[0051] Preferably, when t1≥T1, a single main chord tube 1 is divided into two sections by the dome partition plate 21. Otherwise, each half main chord tube 1 is divided into n sections by the chord tube partition plate 22, where n is a positive integer rounded up to the ratio T1 / t1, and T1=πd 2 L / 8v, where: d is the radius of the main chord tube; L is the arc length of a single main chord tube; v is the pouring speed.

[0052] Specifically, taking the concrete pouring in a large-span arch bridge as an example, the reference value of the initial setting time t1 of the concrete is 10-15h, and the reference value of the pouring speed v is 30-40m 3 / h.

[0053] like Figure 1 As shown, when the ratio T1 / t1 is in the range of (0, 1], half of the main chord tube 1 is not segmented, and the single main chord tube 1 is divided into two sections by the dome partition plate 21.

[0054] like Figure 2As shown, when the ratio T1 / t1 is in the range of (1, 2], half of the main chord tube 1 is divided into two sections by the chord tube partition plate 22, and the single main chord tube 1 is divided into four sections by the dome partition plate 21 and the chord tube partition plate 22.

[0055] like Figure 3 As shown, when the ratio T1 / t1 is in the range of (2, 3], half of the main chord tube 1 is divided into three sections by the chord tube partition plate 22, and the single main chord tube 1 is divided into six sections by the dome partition plate 21 and the chord tube partition plate 22.

[0056] like Figure 4 As shown, when the ratio T1 / t1 is in the range of (3, 4], half of the main chord tube 1 is divided into four sections by the chord tube partition plate 22, and the single main chord tube 1 is divided into eight sections by the dome partition plate 21 and the chord tube partition plate 22.

[0057] By analogy, when the ratio T1 / t1 is in the range of (n-1, n], half of the main chord tube 1 is divided into n sections, and a single main chord tube 1 is divided into 2n sections. The chord tube partition plate 22 is appropriately set slightly above the equal division point of the main chord tube 1 according to the actual pouring volume and construction conditions.

[0058] Preferably, the partition plate 2 is installed by welding during the processing of the arch rib segments, and a plurality of stiffening ribs are welded on both sides of the partition plate 2. As shown in the figure, the stiffening ribs are a combination of cross-stiffening ribs and segmental stiffening ribs to achieve overall reinforcement of the partition plate 2 and ensure stable separation of the partition plate 2 from the relevant main chord tubes 1.

[0059] Preferably, when t2≥T2, the section of the main chord pipe 1 is not graded; otherwise, the section of the main chord pipe 1 is divided into m grades, where m is a positive integer rounded up to the ratio T2 / t2, T2=πd 2 L n / 4v, where d is the radius of the main chord tube; L n is the arc length of the main chord pipe 1 of this section; v is the pouring speed, and a slurry inlet pipe 3 is set at each level. The position of the slurry inlet pipe 3 is related to the setting position of the partition plate 2.

[0060] Specifically, the time t2 during which the concrete maintains its optimal working performance is obtained through a trial mixing test. The trial mixing test includes loading concrete produced in a mixing plant into a tank truck, continuously rotating the mixing drum, sampling concrete every half hour for working performance testing, and plotting a curve. t2 is the time at which the curve sharply drops.

[0061] like Figure 5 As shown, when the ratio T2 / t2 is in the range of (0, 1], the main chord pipe 1 of this section is not graded during pouring, and a slurry inlet pipe 3 is set.

[0062] like Figure 6As shown in FIG, when the ratio T2 / t2 is in the range of (1, 2], the main chord pipe 1 of this section is divided into two stages during pouring, and two slurry inlet pipes 3 are set.

[0063] like Figure 7 As shown, when the ratio T2 / t2 is in the range of (2, 3], the main chord pipe 1 of this section is divided into three stages during pouring, and three slurry inlet pipes 3 are set.

[0064] like Figure 8 As shown in FIG, when the ratio T2 / t2 is in the range of (3, 4], the main chord pipe 1 of this section is divided into four stages during pouring, and four slurry inlet pipes 3 are set.

[0065] By analogy, when the ratio T2 / t2 is in the range of (m-1, m], the main chord pipe 1 of this section is divided into m levels during pouring, and m slurry inlet pipes 3 are set.

[0066] Example 2

[0067] The design method of the large-span arch bridge pipe concrete pouring system of this embodiment, based on Example 1, also includes a step of determining the number of segments based on the pumping pressure σ. When σ is less than 18 MPa, half of the main chord pipe 1 is not segmented, and the single main chord pipe 1 is divided into two sections by the arch partition plate 21. Conversely, each half of the main chord pipe 1 is divided into at least two sections.

[0068] The design method of the large-span arch bridge pipe concrete pouring system of this embodiment is as follows: when the pouring pumping pressure of half of the main chord pipe 1 is greater than 18 MPa, segmentation is required to ensure that the pumping pressure of each section is below 18 MPa. The initial setting time t1 of the concrete and the pumping pressure σ are comprehensively considered. When one of them is determined not to require segmentation but the other is determined to require segmentation, segmentation is performed. When both are determined not to require segmentation, half of the main chord pipe 1 does not need to be segmented, and only the main chord pipes 1 on both sides need to be poured symmetrically. This makes the hierarchical segmentation results more scientific and accurate, and further combines theory with practice to ensure construction period, construction safety and pouring quality.

[0069] It should be noted that the pumping pressure σ can be estimated through a test pump test. The parameter value of 18 MPa is an empirical parameter determined according to the power of the pump 9 during the actual construction process, and can be adapted to the judgment of the pumping pressure σ for concrete pouring in pipes of different span bridge types.

[0070] Preferably, the pumping pressure σ can also be obtained by calculation, and the calculation formula is σ=σ1+σ2, where: σ1 is the pump pipe resistance; σ2 is the pressure of concrete in the main chord pipe; σ1 is calculated according to the industry standard "Technical Code for Concrete Pumping Construction" (JGJT 10), σ2=ρgh, ρ is the concrete density, g is the acceleration of gravity, and h is the height difference between the concrete surface in the pipe and the pump outlet.

[0071] Preferably, the pumping pressure σ can also be obtained by comprehensively estimating from trial pump tests and calculating formulas, so that empirical actuarial calculations are combined with actual construction, making the determination results obtained based on the pumping pressure σ more scientific and accurate, and can be combined with the grading and segmentation results obtained based on the initial setting time of concrete and the maintenance time of the best working performance of concrete, so as to further improve the accuracy of the segmentation and grading of the concrete pouring system in the pipe of a large-span arch bridge, effectively avoid accidents such as pipe blockage and pipe burst caused by inaccurate segmentation and grading of the pouring system, and help to ensure the construction period, construction safety and pouring quality.

[0072] Example 3

[0073] like Figure 9 As shown, the long-span arch bridge pipe concrete pouring system includes a main chord pipe 1, and the main chord pipe 1 is graded and segmented according to the design method of Example 2.

[0074] The grouting system of this embodiment accurately determines the number and position of the partition plates 2 and the slurry inlet pipes 3 according to the accurate number of segments and grades, so that the grouting system structure is combined with the pumping process, effectively avoiding accidents such as pipe blockage and pipe burst caused by concrete properties, pump pipe layout, pumping pressure, etc., which is conducive to ensuring the construction period, construction safety and grouting quality.

[0075] Preferably, a slurry inlet pipe 3, an air extraction pipe 4, a slurry outlet pipe 5, a slag discharge pipe 6 and an exhaust pipe 7 are provided on the main chord pipe 1 according to the grading and segmentation results, and a dome construction platform 8 is provided on the main chord pipe 1.

[0076] Specifically, the exhaust pipe 4 is arranged near the 1.5m line above the chord tube partition plate 22, and is used to connect the upper and lower sections of the main chord tube 1 of the chord tube partition plate 22 to ensure the connectivity of vacuum extraction during the pouring construction.

[0077] Specifically, a slurry discharge pipe 5 for discharging floating slurry is set near the 0.5m line below the chord tube partition plate 22 and on both sides of the arch crown partition plate 21, and a slurry discharge pipe 5 for vibration is set at an appropriate position on the top of the arch foot of the main chord tube 1 near the arch seat, so as to ensure that the floating slurry can be discharged smoothly when the concrete in each section of the main chord tube 1 is fully poured, and the pouring quality of the concrete in the initial stage is ensured, thereby ensuring the overall quality of the concrete in the main chord tube 1.

[0078] Specifically, a slag discharge pipe 6 is provided at a position above the arch foot and the chord tube partition plate 22, that is, at the arch foot position of each section of the main chord tube 1, and is provided directly below the main chord tube 1. It is used to clean the main chord tube 1 with water before pouring concrete in the tube, so that iron filings, rust and other debris inside the tube are discharged together with water from the slag discharge pipe.

[0079] Specifically, the exhaust pipe 7 is arranged in the top area of each section of the main chord pipe 1, and several exhaust pipes 7 are arranged in the dome area of the main chord pipe 1. In this embodiment, the exhaust pipes 7 arranged in the dome are preferably arranged, and the spacing between adjacent exhaust pipes 7 is 2-3m, specifically 2.5m, to ensure that the air in the concrete in the pipe is smoothly discharged to avoid the loose concrete caused by bubbles.

[0080] Specifically, the arch construction platform 8 is set in the arch area for placing mechanical equipment such as vacuum pumps and water tanks. When pouring concrete at the lower end of the main chord pipe 1, vacuum is drawn from above the main chord pipe 1 to assist the concrete surface to rise smoothly during the pouring process.

[0081] Example 4

[0082] like Figure 10-15 As shown in the figure, the pouring method of the large-span arch bridge pipe concrete pouring system adopts the construction sequence of first inner chord pipe and then outer chord pipe, first lower chord pipe and then upper chord pipe, and symmetrical pouring on both sides according to the position of the main chord pipe 1, and adopts a pumping process combined with vacuum system assistance and staged pressure injection.

[0083] The pouring method of the large-span arch bridge pipe concrete pouring system of this embodiment is as follows: Figure 10 As shown, the concrete pouring in the chord tube is carried out in the order of ABCDEFGH. On the basis of scientifically designing the number of rings and segments of the main chord tube, the hierarchical and segmented structure division of the pouring system is made more accurate, which provides a favorable structural foundation for the pouring process, enables the pouring process to proceed smoothly, is conducive to improving the pouring quality, and ensures the construction period and construction safety. At the same time, the concrete pouring in the tube is carried out in a specific pouring sequence, so that the overall stability of the large-span arch bridge during the pouring process is coordinated with the pouring process, ensuring the structural stability of the pouring process.

[0084] like Figure 11-Figure 15 As shown, this embodiment is described by taking a single main chord pipe 1 divided into four sections and four levels and using two pumps 9 to perform pipe concrete pouring as an example, specifically including the following steps:

[0085] S1. Flushing the main chord pipe 1: Pump water from the river to the vault water tank, and release water from the vault to flush the inside of the main chord pipe 1 until the water output from the slag discharge pipe 6 is clear and free of debris;

[0086] S2. First-stage concrete pumping construction: Pump cement mortar through pump 9 to lubricate the pump pipe to reduce the concrete pumping resistance. After lubrication is completed, connect the pump pipe of pump 9 to the first-stage main chord pipe 1 and start pumping concrete. When the top surface of the concrete exceeds the 3m line position of the first-stage slurry inlet, start the vacuum system and maintain the vacuum degree within the range of -0.08~-0.06MPa. Continue pumping concrete until the concrete surface reaches the 1m line position below the second-stage concrete surface. Then stop pumping and turn off the vacuum system.

[0087] S3, second-stage concrete pumping construction: After lubricating the pump pipe by pumping cement mortar through another pump 9, connect it to the second-stage main chord pipe 1. When the vacuum degree in the main chord pipe 1 reaches 0, the second-stage concrete pumping is carried out using the same pumping method as S1. When the top surface of the concrete approaches the partition plate 2, the vacuum system is turned off, the slurry discharge pipe 5 is opened, and concrete is slowly pumped to discharge the floating slurry. After the floating slurry is completely discharged, the pumping is stopped and the slurry discharge pipe 5 is closed, completing the second-stage concrete pumping;

[0088] S4, nth stage concrete pumping construction: repeat S2 to S3 in sequence to complete the subsequent concrete pumping construction;

[0089] S5. Arch exhaust operation: After the arch slurry is discharged, stop pumping and let it stand for 30 minutes to 60 minutes, preferably 30 minutes. Open the exhaust pipe valves 7 one by one. When no gas comes out or thick slurry comes out, close the valves to complete the pouring construction of a single main chord pipe. During the exhaust process, if the concrete cross-section in the arch slurry outlet pipe 5 decreases, add slurry in time to ensure the quality of concrete pouring in the main chord pipe 1.

[0090] Specifically, in S1, a high-lift pump with a lift of not less than 200m is installed in the river, and a pumping pipe is arranged along the upper chord of the arch rib to pump the river water to the water tank of the arch construction platform 8 for storage. A water pump is installed on the arch, and the water pump outlet is connected to the two slurry discharge pipes 5 through a water pipe. The check valves on the slurry inlet pipes 3 at all levels are closed, and the valve on the slag discharge pipe 6 near the arch foot is opened to carry out pumping operations. A large amount of clean water is injected into the main chord pipe 1 from the slurry discharge pipe 5 to flush the inner wall of the main chord pipe 1. The water flow carries debris and is discharged through the slag discharge pipe 6 until the water output from the slag discharge pipe 6 is clear and free of debris. The pumping is stopped and the valve on the slag discharge pipe 6 is closed.

[0091] Specifically, in S2, the mortar pumped out during the lubrication operation is discharged into the drainage funnel and discharged outside the arch rib structure to avoid contaminating the arch rib anti-corrosion layer. After the lubrication is completed, the pump pipe of the pump 9 is connected to the first-stage slurry inlet pipe 3, the slag discharge pipe 6 at the arch foot is welded and closed, the vacuum system is connected to the slurry outlet pipe 5 at the arch top, and the arch top slurry outlet pipe 5 is connected to the air extraction hole, and the valves of the slurry inlet pipes 3 above the first stage are closed. After the concrete is fully matured, the pump 9 is started for pumping. When the concrete is discharged from the vibrating slurry outlet pipe 5, a vibrating rod is inserted from the vibrating slurry outlet pipe 5 to vibrate and exhaust the concrete in the arch foot section. When concrete continuously emerges from the pipe mouth, the vibrating slurry outlet pipe 5 is closed, and the pouring is continued until the concrete boundary surface exceeds the 3m line position of the first-stage slurry inlet, the vacuum system is started, the pump 9 is paused, and the vacuum degree reaches the requirement before continuing to pump.

[0092] Specifically, after each section of concrete is pumped, the floating slurry must be discharged accordingly.

[0093] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. The design method of the pipe concrete pouring system of a long-span arch bridge is characterized by: include: The steps of determining the number of segments of a single main chord pipe (1) according to the initial setting time t1 of concrete and the time T1 required to fill half of the main chord pipe (1); determining the number of grades of each section of the main chord pipe (1) according to the time t2 of maintaining the best working performance of concrete and the time T2 required to fill a section of the main chord pipe (1); determining the location and number of partition plates (2) according to the segmentation results; and determining the number of slurry inlet pipes (3) according to the classification results. The time t2 for maintaining the optimal working performance of the concrete is obtained through a trial mixing test. The trial mixing test includes: loading the concrete produced by the mixing plant into a tank truck, continuously rotating the mixing drum, taking concrete every half an hour to test the working performance and plotting a curve. t2 is the time when the curve drops sharply. When t1 ≥ T1, a single main chord tube (1) is divided into two sections by the dome partition plate (21); otherwise, each half main chord tube (1) is divided into n sections by the chord partition plate (22), where n is a positive integer obtained by rounding up the ratio T1 / t1. When t2≥T2, the main chord pipe (1) of this section is not graded; otherwise, the main chord pipe (1) of this section is divided into m levels, where m is a positive integer obtained by rounding up the ratio T2 / t2, and a slurry inlet pipe (3) is provided at each level.

2. The design method of the long-span arch bridge pipe concrete pouring system according to claim 1 is characterized in that: T1=πd 2 L / 8v, where: d is the radius of the main chord (1); L is the arc length of a single main chord (1); v is the injection speed; T2=πd 2 L n / 4v, where: d is the radius of the main chord (1); L n is the arc length of the main chord tube (1); v is the injection speed.

3. The design method of the long-span arch bridge pipe concrete pouring system according to claim 1 is characterized in that: The method further includes a step of determining the number of segments according to the pumping pressure σ. When σ is less than 18 MPa, a single main chord pipe (1) is divided into two segments by the dome partition plate (21). Otherwise, each half main chord pipe (1) is divided into at least two segments.

4. The design method of the long-span arch bridge pipe concrete pouring system according to claim 3 is characterized in that: Pumping pressure σ = σ1 + σ2, where σ1 is the pump pipe resistance; σ2 is the concrete pressure in the main chord pipe (1).

5. The design method of the long-span arch bridge pipe concrete pouring system according to claim 3 is characterized in that: The pumping pressure σ is estimated through a test pump test. 6.Long-span arch bridge pipe concrete pouring system, characterized by: The main chord pipe (1) is comprised of a main chord pipe (1), and the main chord pipe (1) is graded and segmented according to the design method of the long-span arch bridge pipe concrete pouring system according to any one of claims 1 to 5.

7. The long-span arch bridge pipe concrete pouring system according to claim 6, characterized in that: The main chord pipe (1) is provided with a slurry inlet pipe (3), an air extraction pipe (4), a slurry outlet pipe (5), a slag discharge pipe (6) and an exhaust pipe (7) according to the grading and segmentation results, and the main chord pipe (1) is provided with an arch construction platform (8).

8. The pouring method of the long-span arch bridge pipe concrete pouring system according to claim 7, characterized in that: According to the position of the main chord pipe (1), the construction sequence is to first fill the inner chord pipe and then the outer chord pipe, first fill the lower chord pipe and then the upper chord pipe, and symmetrically pour the chord pipe on both sides. A pumping process combining vacuum system assistance and graded pressure injection is adopted.

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