Construction method for precast wet joint of drainage box culvert under height limit of non-stop airport

Abstract

The application relates to a precast wet joint construction method of an airport non-stop high-limit drainage box culvert, which comprises the following steps: S1, precasting a box culvert precast section outside a flight area, and reserving post-poured belt steel bars at the front and back ends of the box culvert precast section; S2, excavating a foundation groove within an ultra-clean construction time; S3, constructing a cushion layer in the foundation groove within the ultra-clean construction time; S4, constructing a positioning structure of the box culvert precast section in the foundation groove, and hoisting the box culvert precast section onto the cushion layer within the ultra-clean construction time; S5, binding the post-poured belt steel bars of two adjacent box culvert precast sections; S6, installing inner and outer templates of the post-poured belt steel bars; when the inner template of the post-poured belt is installed, two teams of workers respectively drive construction transport vehicles into the interior of the box culvert from the two ends, and gradually construct towards the outside; S7, pouring concrete at the post-poured belt position; and S8, backfilling wet lean concrete in a fat groove between the box culvert and the foundation groove. The application has the effects of facilitating rapid construction of a box culvert drainage ditch and shortening a construction period.

Description

Technical Field

[0001] This application relates to the field of airport drainage construction, and in particular to a prefabricated wet-jointing construction method for drainage box culverts under airport non-stop height restrictions. Background Technology

[0002] Airport non-stop construction refers to construction and maintenance work carried out within the airport's flight area without affecting the airport's safety and normal operation.

[0003] Airport drainage ditch construction falls under the scope of airport maintenance work. Traditional methods often involve cast-in-place concrete to create drainage culverts within a planned area. This process involves steel reinforcement hoisting and concrete pouring, requiring the use of large machinery such as excavators, dump trucks, concrete mixer trucks, and cranes. However, height restrictions within the flight zone are extremely strict. While procedures within the airspace can be carried out 24 hours a day, large equipment such as excavators, dump trucks, concrete mixer trucks, pump trucks, and truck-mounted cranes exceed the height limits. Therefore, construction work can only be carried out from the end of each night's flight until one hour before the first flight of the following day, when there are no height restrictions. However, construction time is limited, typically only four hours per day.

[0004] Therefore, the inventors believe that this on-site pouring construction method not only affects the airport's airspace height limit, but also requires a long working time inside the airport, and short-term airport shutdowns often cannot meet the conditions for continuous construction. Summary of the Invention

[0005] To facilitate rapid construction of airport drainage ditches, this application provides a prefabricated wet-jointing construction method for drainage box culverts under airport non-stop height restrictions.

[0006] This application provides a prefabricated wet-jointing construction method for drainage box culverts under airport non-stop height restrictions, which adopts the following technical solution:

[0007] A prefabricated wet-jointing construction method for drainage box culverts under airport height restrictions without interrupting flight operations includes the following steps:

[0008] S1: Precast box culvert segments outside the flight area, wherein the front and rear ends of the precast box culvert segments are reserved with post-cast reinforcement strips;

[0009] S2: Excavation of foundation trench within the ultra-clear construction period;

[0010] S3: During the ultra-clear construction period, a cushion layer is constructed in the foundation trench;

[0011] S4: Positioning structure for box culvert construction within the foundation trench, during ultra-clear construction time, to hoist the precast box culvert section onto the foundation layer;

[0012] S5: Tie the post-cast reinforcement bars of two adjacent precast box culvert sections.

[0013] S6: Install the inner and outer formwork for the post-cast strip reinforcement: When installing the inner formwork for the post-cast strip, two teams of workers drive construction transport vehicles to enter the box culvert from both ends and gradually construct outwards. The construction transport vehicle includes a control module, a walking module, a support seat module for workers to ride on, and a storage module for holding materials.

[0014] S7: Concrete is poured at the post-cast strip;

[0015] S8: The trench between the box culvert and the foundation trench is backfilled with wet, lean concrete.

[0016] By adopting the above technical solution, 80% of the steel reinforcement, formwork, and concrete work for the main body of the box culvert was moved to prefabrication outside the flight area perimeter, greatly reducing the environmental impact and safety hazards on the operating runway. Construction time within the flight area was significantly shortened, effectively reducing the window of opportunity for construction without interrupting operations. During airport maintenance hours, only foundation excavation, subgrade pouring, and box culvert hoisting are required. Other construction work can be carried out at other times, reducing the restrictions imposed by airport airspace height limitations and significantly shortening the construction period.

[0017] Because the construction space inside the box culvert is narrow and the height is low, when installing the formwork for the post-cast strip section, workers can drive the construction transport directly into the box culvert and install the formwork in a seated position, which is more convenient for the workers.

[0018] Preferably, before prefabricating the precast sections of the box culvert, preconstruction preparations are carried out, including:

[0019] S01: Select a solid area of ​​soil outside the flight zone, compact it, and test the soil bearing capacity until the soil bearing capacity reaches ±20-30% of the safe bearing capacity;

[0020] S02: Construct a concrete strip base within the selected area, and carry out the construction of the precast box culvert on the strip base. The strip base provides a bottom surface with consistent flatness for the precast box culvert section.

[0021] S03: Process the transverse frame reinforcement, longitudinal reinforcement, box culvert axial formwork, and outer formwork of each box culvert prefabricated section according to its length.

[0022] By adopting the above technical solution, the strip base is constructed in advance to provide a plane with consistent flatness at each position for the prefabrication of the box culvert, ensuring that the elevation of each prefabricated box culvert section is consistent.

[0023] Preferably, the prefabrication construction of box culverts includes:

[0024] S11: Lay a layer of plastic film on the top surface of the strip base; S12: Place the box culvert shaft formwork on the plastic film, and then pass the longitudinal steel bars through the box culvert shaft formwork. The two ends of the longitudinal steel bars protrude about 40 - 50 cm from the two ends of the box culvert shaft formwork to form the post-cast strip steel bars;

[0025] S13: Surround the transverse frame steel bars on the longitudinal steel bar layer;

[0026] S14: Embed lifting hooks in the top slab of each box culvert precast segment: The lifting hooks are in a "U" shape for the lifting of the box culvert, including a main body part protruding from the top slab of the box culvert and hook parts connected to both sides of the main body part. The hook parts are hooked reversely on the longitudinal steel bars of the box culvert;

[0027] S15: Construct the outer side formwork, pour concrete, and remove the formwork after the concrete strength meets the requirements.

[0028] By adopting the above technical solutions, the embedded lifting hooks facilitate hooking and lifting the box culvert precast segments into the foundation trench. Each box culvert precast segment reserves 40 - 50 cm of post-cast strip steel bars, which is convenient for connecting the heads and tails of two adjacent box culvert precast segments.

[0029] Preferably, four lifting hooks are provided, and the four lifting hooks are evenly distributed at the four corners of the box culvert precast segment.

[0030] By adopting the above technical solutions, it is convenient to lift the box culvert precast segment smoothly and ensure the balance of the lifting.

[0031] Preferably, the cushion layer pouring construction in S3 includes:

[0032] S31: Conduct a foundation bearing capacity test in the foundation trench. When the foundation bearing capacity does not meet the requirements, carry out overexcavation treatment;

[0033] S32: Lay a 8 - 12 cm thick crushed stone cushion layer in the foundation trench after the foundation bearing capacity meets the requirements;

[0034] S33: Pour a 10 cm thick concrete cushion layer on the crushed stone cushion layer. Use a 2 m straightedge and a feeler gauge to measure. Take the maximum value for three consecutive feet. Control the flatness of the concrete cushion layer not to exceed 5 mm of the specification requirements.

[0035] By adopting the above technical solutions, the concrete cushion layer provides a flat base for the lifting of the box culvert precast segments and avoids excessive height differences between each box culvert precast segment.

[0036] Preferably, the construction of the positioning structure includes:

[0037] S41: Based on the width of the box culvert, measure and lay out lines on both sides of the foundation layer to form two positioning lines; S42: Fix construction segment positioning piles at the positions of the positioning lines on both sides: the positioning piles arranged symmetrically on the left and right are a group, and at least two groups are fixed on both sides of each box culvert.

[0038] By adopting the above technical solutions, we can ensure that all prefabricated box culvert sections are installed on a horizontal straight line, thus ensuring the straightness of the drainage ditch and reducing the occurrence of subsequent water leakage.

[0039] Preferably, the top of the positioning pile facing the precast box culvert section is processed into a guide slope, and the bottom of the positioning pile facing the precast box culvert section is processed into a positioning vertical plane, with the outer side of the positioning vertical plane flush with the positioning line.

[0040] By adopting the above technical solution, the two guide slopes form an outward-opening "eight" shape, which makes it easier to place the prefabricated box culvert sections.

[0041] Preferably, in S3, the post-cast strip reinforcement of two adjacent precast box culvert sections is lapped and tied with stirrups.

[0042] By adopting the above technical solution, two precast box culvert sections were hoisted into the foundation trench, and the reinforcing bars of the post-cast strip were directly lapped and tied with stirrups, thus connecting the two adjacent precast box culvert sections end to end. The operation is simple and the construction efficiency is improved.

[0043] Preferably, the walking module is a tracked wheel mechanism, and the support seat module includes a support plate connected between the two tracked wheel mechanisms, a seat for workers to sit on, and a height adjustment component installed between the support plate and the seat. The height adjustment component and the tracked wheel mechanism are both connected to the control module to adjust the height of the seat as the workers work.

[0044] By adopting the above technical solution, and by adjusting the height of the seat, workers can raise the seat height when fixing the upper part of the template and lower the seat height when fixing the lower part of the template, making construction more convenient.

[0045] Preferably, the support module includes two units respectively disposed on both sides, so that two workers can carry out construction on both sides simultaneously.

[0046] By adopting the above technical solution, two people can work on both sides simultaneously, which greatly improves construction efficiency.

[0047] In summary, this application includes at least one of the following beneficial technical effects:

[0048] 1. This application allows for the prefabrication of box culvert sections outside the flight zone, enabling 80% of the main body of the box culvert to be manufactured in advance. This reduces the restrictions on construction caused by airport airspace height restrictions and saves construction time. By installing positioning structures in the foundation trench, it can be ensured that each prefabricated box culvert section overlaps in a straight line.

[0049] 2. By adjusting the height adjustment component, workers can easily adjust the height of the chair according to the construction height, making construction more convenient;

[0050] 3. By reserving reinforcement bars for the post-cast strip and using lap splicing to connect the reinforcement bars of the post-cast strips of two adjacent precast box culvert sections, the connection between the two precast box culvert sections becomes more convenient. Attached Figure Description

[0051] Figure 1 This is the construction flowchart of this application.

[0052] Figure 2 This is a structural schematic diagram of the prefabricated box culvert section after the top slab is hidden.

[0053] Figure 3 This is a magnified view of a portion of the hook.

[0054] Figure 4 This is a schematic diagram showing the state of the precast box culvert sections being hoisted onto the foundation layer in step 4.

[0055] Figure 5 This is a schematic diagram of the positioning structure.

[0056] Figure 6 This is a schematic diagram showing the state of the post-cast strip reinforcement connection.

[0057] Figure 7 This is a structural schematic diagram of a construction transport vehicle.

[0058] Figure 8 This is a schematic diagram of the height adjustment component.

[0059] Explanation of reference numerals in the attached drawings: 1. Precast box culvert section; 11. Transverse frame reinforcement; 12. Longitudinal reinforcement; 13. Box culvert axial formwork; 14. Outer formwork; 15. Hook; 151. Main body; 152. Hooking part; 2. Post-cast strip reinforcement; 3. Strip base; 4. Foundation trench; 5. Subbase; 6. Positioning structure; 61. Positioning pile; 611. Guide slope; 612. Positioning vertical plane; 62. Positioning plate; 7. Stirrups; 8. Construction transport vehicle; 81. Walking module; 82. Support seat module; 821. Support plate; 822. Seat; 823. Height adjustment component; 8231. Threaded rod; 8232. Slider; 8233. Support rod; 8234. Drive motor; 824. Storage module; 825. Corrugated protective cover. Detailed Implementation

[0060] The following is in conjunction with the appendix Figure 1-8 This application will be described in further detail.

[0061] This application discloses a method for the prefabricated wet-jointing construction of drainage box culverts under airport height restrictions without interrupting flight operations. (Refer to...) Figures 1-8 The prefabricated wet-jointing construction method for drainage box culverts under airport non-stop height restrictions includes the following steps:

[0062] S1: Precast box culvert segment 1 outside the flight area, with post-cast reinforcement bars 2 reserved at both ends of the precast box culvert segment 1.

[0063] Before the prefabrication of the first segment of the precast box culvert, pre-construction preparations are carried out, including:

[0064] S01: Select a solid area of ​​soil outside the flight zone, compact it with a road roller, and test the soil bearing capacity until the soil bearing capacity reaches ±20-30% of the safe bearing capacity;

[0065] S02: Concrete strip base 3 is poured in the selected area. The precast box culvert construction is carried out on the strip base 3, which provides a flat bottom surface for the box culvert. The strip base 3 of this application is made of C30 concrete and is 20cm thick. According to the predetermined width of the precast box culvert section 1, a 20-30cm allowance is reserved on both sides of the strip base 3.

[0066] S03: Fabricate the transverse frame reinforcement 11, longitudinal reinforcement 12, box culvert axial formwork 13, and outer formwork 14 for each precast box culvert segment 1 according to the predetermined length. The formwork fabrication dimensions shall strictly follow the dimensions in the construction drawings to avoid significant misalignment during later assembly.

[0067] After the preparatory work is completed, the construction of precast box culvert section 1 will proceed, including the following steps:

[0068] S11: Lay a layer of plastic film on the top surface of the strip base 3;

[0069] S12: Place the box culvert axial formwork 13 on the plastic film, and insert the longitudinal steel bars 12 inside the box culvert axial formwork 13. The two ends of the longitudinal steel bars 12 protrude from the two ends of the box culvert axial formwork 13 with an overlap length of about 40~50cm, forming the post-cast strip steel bars 2.

[0070] S13: Enclose the transverse frame reinforcement 11 on the layer of the longitudinal reinforcement 12;

[0071] S14: Each precast box culvert segment 1 has a pre-embedded hook 15 in its top slab. Specifically, the hook 15 is U-shaped and used for hoisting the precast box culvert segment 1. It includes a main body 151 protruding from the top slab of the precast box culvert segment 1 and hook portions 152 connected to both sides of the main body 151. The hook portions 152 are hooked onto the longitudinal reinforcing bars 12 of the precast box culvert segment 1. To ensure the stability of the hooks, each precast box culvert segment 1 has multiple hooks 15. This application uses four hooks 15, which are evenly distributed at the four corners of the precast box culvert segment 1 to facilitate balanced hoisting of the precast box culvert segment 1.

[0072] S15: Concrete for the outer formwork 14 is poured using a full-section, one-time concrete pour. During pouring, the concrete is thoroughly vibrated until no more bubbles appear. Due to the full-section pouring, two vent holes / vibration holes are installed in the middle of the bottom slab cover formwork to ensure adequate vibration of the bottom slab. The formwork is removed after the concrete strength meets the requirements. The side formwork can be removed one day after pouring, while the top slab formwork is removed when the concrete strength reaches 75% or more. To facilitate smooth formwork removal, a release agent is applied to the box culvert axial formwork 13 and the outer formwork 14. After removing the formwork, finishing and curing are carried out for at least 7 days. The strip base 3 can only be lifted off when the concrete strength reaches 100%, and then the next batch of precast box culvert sections 1 can be constructed.

[0073] Taking a 200m long box culvert within a height-restricted area as an example, this application designs each box culvert precast section 1 to be 2m long, with a 0.5m post-cast strip. A total of 80 sections need to be precast, achieving a precast ratio of 80%, which greatly improves construction efficiency and shortens the construction period.

[0074] S2: Excavation of foundation trench 4 during ultra-clear construction time.

[0075] During runway nighttime maintenance hours, when there are no height restrictions, excavators will be used to excavate trench 4, which exceeds the clearance height limit. The excavated soil will be loaded into dump trucks and removed from the site. The tops of the dump trucks must be sealed to prevent spillage and dust. Due to the large number of security vehicles entering and exiting the airport's flight area, the process is somewhat cumbersome. To ensure construction efficiency, this application utilizes 2 excavators and 6 dump trucks, with simultaneous excavation in both areas.

[0076] To further ensure construction safety, a construction warning line will be established within the flight area before excavation of foundation trench 4. This application proposes installing several heavy-duty rubber cones at the junction with the runway entrance, with a 3-meter spacing between each cone. A ring-shaped counterweight sandbag will be installed at the bottom of each heavy-duty rubber cone, and a solar-powered red warning light will be installed at the top, serving as a warning line for the construction area. No construction personnel or vehicles are permitted to exceed this area and enter the area near the runway.

[0077] S3: During the ultra-clearance construction period, the cushion layer 5 is constructed within the foundation trench 4. This specifically includes the following steps:

[0078] S31: Conduct a foundation bearing capacity test in trench 4. If the foundation bearing capacity does not meet the requirements, over-excavation treatment shall be carried out.

[0079] S32: After the foundation bearing capacity meets the requirements, the loader enters the site and lays an 8-12cm thick crushed stone cushion layer in the foundation trench 4;

[0080] S33: During the airport's nighttime maintenance period, concrete mixer trucks and concrete pump trucks will enter the site to pour a 10cm thick concrete subbase on the crushed stone subbase.

[0081] To ensure the flatness of the concrete subbase, a 2m straightedge and feeler gauge were used for on-site measurement. The maximum value was taken for three consecutive measurements to control the flatness of the concrete subbase to not exceed the specification requirement of 5mm.

[0082] S4: The positioning structure 6 for the precast box culvert segment 1 is constructed within the foundation trench 4. During the ultra-clearance construction period, the precast box culvert segment 1 is hoisted onto the foundation layer 5. Specifically, the following steps are included:

[0083] S41: Based on the width of the precast box culvert section 1, use a level and a total station to measure and lay out the lines on both sides of the subbase 5 to form two positioning lines;

[0084] S42: Fix the construction segment positioning piles 61 at the positions of the positioning lines on both sides. The positioning piles 61 arranged symmetrically on the left and right are a group. At least two groups are fixed on both sides of each box culvert prefabricated segment 1. The two groups of positioning piles 61 are located at the beginning and end of the box culvert prefabricated segment 1, respectively.

[0085] S43: The first precast box culvert segment 1 was hoisted outside the flight area for trial installation;

[0086] S44: During the airport's nighttime maintenance period, use a crane hook to lift four hooks 15, so that the precast box culvert section 1 is lifted and transported between the two positioning piles 61.

[0087] The accuracy of the positioning piles 61 directly affects the straightness of the hoisting of the precast box culvert segment 1. To ensure that the positioning piles 61 on the same side are aligned on the same horizontal line as much as possible, two positioning piles 61 are integrated onto a single positioning plate 62, with the side plane of each positioning pile 61 flush with the side plane of the positioning plate 62. During installation, the side plane of the positioning plate 62 is aligned with the positioning line, and expansion bolts are used to fix both ends of the positioning plate 62. When hoisting the precast box culvert segment 1, the two plates on the same positioning plate 62 are aligned with the beginning and end ends of the two precast box culvert segments 1, respectively, ensuring that the connection points of two adjacent precast box culvert segments 1 are in a straight line. After the precast box culvert segment 1 is hoisted, the positioning plates 62 are gradually removed.

[0088] To minimize the impact of the positioning piles 61 on the hoisting of the precast box culvert segment 1, the top of the positioning pile 61 on the side facing the precast box culvert segment 1 is machined into a guide slope 611, and the bottom of the positioning pile 61 on the side facing the precast box culvert segment 1 is machined into a positioning vertical plane 612, with the outer side of the positioning vertical plane 612 flush with the positioning line. The two guide slopes 611 of the two positioning piles 61 form an outwardly flared V-shape, facilitating the placement of the precast box culvert segment 1.

[0089] S5: Tie the post-cast strip reinforcement 2 of two adjacent precast box culvert sections 1. The post-cast strip reinforcement 2 of two adjacent precast box culvert sections 1 are connected by lap splicing and tied with reinforcement bars.

[0090] S6: Install the inner and outer formwork for the post-pouring strip reinforcement:

[0091] S61: Before pouring, wash the cross-sections of the precast sections on both sides to remove loose stones and laitance.

[0092] S62: During the installation of the internal formwork of the post-cast strip, two teams of workers drive construction transport vehicles 8 from both ends into the box culvert and gradually work outwards. The construction transport vehicle 8 includes a control module, a travel module 81, a support seat module 82 for workers to sit on, and a storage module 824 for holding materials. The storage module 824 includes a storage hopper installed at the rear. In use, the materials to be used are placed in the storage hopper, and then workers sit in the support seat module 82 and drive the construction transport vehicle 8 from both ends of the box culvert, meeting at the middle position. During construction, the workers remain seated on the support seat module 82 to install the inner formwork. This facilitates formwork installation in confined spaces and improves construction efficiency.

[0093] Specifically, the walking module 81 includes two track wheel mechanisms, and the support module 82 includes a support plate 821 installed between the two track wheel mechanisms, a seat 822 for workers to sit on, and a height adjustment component 823 installed between the support plate 821 and the seat 822. The height adjustment component 823 and the track wheel mechanisms are both connected to the control module so that the height of the seat 822 can be freely adjusted according to the worker's construction.

[0094] In one specific structural embodiment, the height adjustment assembly 823 includes a threaded rod 8231 with oppositely helical threads at both ends, two sliders 8232 threadedly connected to both ends of the threaded rod 8231, a support rod 8233 hinged between each slider 8232 and the seat 822 and the support plate 821, and a drive motor 8234 that drives the threaded rod 8231 to rotate. The drive motor 8234 and the threaded rod 8231 are mounted on a mounting plate. The two support rods 8233 on the same slider 8232 are symmetrically arranged, and the two sets of support rods 8233 on the two sliders 8232 are also symmetrically arranged. The drive motor 8234 drives the threaded rod 8231 to rotate, causing the two sliders 8232 to move closer or further apart. As the two sliders 8232 move closer or further apart, the angle between the support rod 8233 and the threaded rod 8231 changes, causing the seat 822 to rise or fall. To facilitate worker control of the height adjustment component 823 during construction, the control module includes a PLC control unit and a manual lever (not shown in the figure) connected to the PLC control unit. For ease of operation, the manual lever is located on the worker's right-hand side. When the worker needs to secure the upper part of the template, they control the manual lever to trigger a start-up signal to the PLC control unit. The PLC control unit then starts the drive motor 8234, causing the two sliders 8232 to move closer together, thus raising the seat 822. When the worker needs to secure the lower part of the template, they simply move the manual lever in the opposite direction. The height adjustment component is covered with a corrugated protective cover 825 to reduce the probability of wear and tear on the height adjustment component 823 due to moisture or impact.

[0095] To improve construction efficiency, the support module 82 is provided with two oppositely positioned parts, so that two workers can sit back to back and install the template on both sides simultaneously.

[0096] S7: Concrete is poured at the post-cast strip;

[0097] The concrete used is micro-expansion concrete of the same grade as that used in the box culvert. The quality of vibration of the post-cast strip is particularly critical and is a key operation to ensure the integrity of the box culvert. This application adopts on-site supervision to ensure the quality of vibration, especially at the joint between the old and new sections, where vibration must be sufficient and the surface must be smooth and even. After final setting, geotextile is covered for wet curing, and the curing time is not less than 14 days.

[0098] The volume of concrete in the post-cast strip is small, so there is no need to use a pump truck for pouring. There is no risk of excessive clearance during construction, which saves construction time.

[0099] S8: Wet and lean concrete is backfilled in the trench between the precast box culvert section 1 and the foundation trench 4.

[0100] The entire cross-section of the box culvert is backfilled with wet lean concrete up to the bottom elevation of the water-stabilized base course of the slideway, which improves the compaction and bearing capacity of the backfill in the trenches on both sides. At the same time, it can improve the overall integrity of the box culvert and also improve the waterproof performance of the construction joints.

[0101] The implementation principle of the prefabricated wet-jointing construction method for drainage box culverts under non-stop flight and height restrictions in this application embodiment is as follows: 80% of the steel reinforcement, formwork, and concrete work for the main body of the box culvert is adjusted to be prefabricated outside the flight area boundary, which greatly reduces the environmental impact and safety hazards on the operating runway. The construction time within the flight area is greatly shortened, indirectly reducing the window period for safety hazards during non-stop flight construction. During airport maintenance periods, only the excavation of the foundation trench 4, the pouring of the subbase 5, and the hoisting of the box culvert need to be carried out. Other construction can be carried out at other times, reducing the restrictions on construction by airport airspace height restrictions and greatly shortening the construction period. In addition, the costs of management fees, machinery fees, and labor costs are greatly reduced, achieving good economic benefits.

[0102] The above are all preferred embodiments of this application, and are not intended to limit the scope of protection of this application. Therefore, all equivalent changes made in accordance with the structure, shape and principle of this application should be covered within the scope of protection of this application.

Claims

1. A method for prefabricated wet-jointing construction of drainage box culverts under airport non-stop height restrictions, characterized in that: It includes the following steps: S1: Prefabricate the box culvert precast segments (1) in sections outside the flight area, and reserve the post-cast strip steel bars (2) at the front and rear ends of the box culvert precast segments (1); S2: Excavate the foundation trench (4) during the ultra-clearance construction time; S3: During the ultra-clearance construction time, construct the cushion layer (5) in the foundation trench (4); S4: Construct the positioning structure (6) of the box culvert precast segments (1) in the foundation trench (4), and hoist the box culvert precast segments (1) onto the cushion layer (5) during the ultra-clearance construction time; S5: Tie the post-cast strip steel bars (2) of two adjacent box culvert precast segments (1); S6: Install the inner and outer templates of the post-cast strip steel bars (2): When installing the inner template of the post-cast strip, two teams of workers drive the construction transport vehicles (8) into the box culvert from both ends respectively and gradually construct towards the outside. The construction transport vehicle (8) includes a control module, a walking module (81), a support seat module (82) for workers to ride on, and a storage module (824) for storing materials; S7: Pour concrete at the post-cast strip part; S8: Backfill lean wet concrete in the fat groove between the box culvert and the foundation trench (4).

2. The prefabricated wet-jointing construction method for drainage box culverts under airport non-stop height restriction as described in claim 1, characterized in that: Before prefabricating the box culvert precast segments (1) in sections, carry out pre-construction preparations, including: S01: Select a solid area on the unpaved area outside the flight area, compact it, and detect the bearing capacity of the land until the bearing capacity of the land reaches ±20 - 30% of the safe bearing capacity; S02: Construct a concrete strip base (3) in the selected area, and the prefabrication of the box culvert is carried out on the strip base (3). The strip base (3) provides a bottom surface with consistent flatness for the box culvert precast segments (1); S03: Process the transverse frame steel bars (11), longitudinal steel bars (12), box culvert shaft templates (13), and outer templates (14) of each section of the box culvert precast segments (1) according to the length of the box culvert precast segments (1).

3. The prefabricated wet-jointing construction method for drainage box culverts under airport non-stop height restriction as described in claim 2, characterized in that: The prefabrication construction of the box culvert includes: S11: Lay a layer of plastic film on the top surface of the strip base (3); S12: Place the box culvert shaft template (13) on the plastic film, and then pass the longitudinal steel bars (12) through the box culvert shaft template (13). The two ends of the longitudinal steel bars (12) protrude 40 - 50 cm from the two ends of the box culvert shaft template (13) to form the post-cast strip steel bars (2); S13: Surround the transverse frame steel bars (11) on the longitudinal steel bar (12) layer; S14: Embed lifting hooks (15) in the top plate of each section of the box culvert precast segments (1): The lifting hooks (15) are in a "ji" shape and are used for hoisting the box culvert, including a main body part (151) protruding from the top plate of the box culvert and hook parts (152) connected to both sides of the main body part (151). The hook parts (152) are hooked reversely on the longitudinal steel bars (12) of the box culvert; S15: Construct the outer template (14), pour concrete, and remove the template after the concrete strength meets the requirements.

4. The prefabricated wet-jointing construction method for drainage box culverts under airport non-stop height restriction as described in claim 3, characterized in that: Four lifting hooks (15) are provided, and the four lifting hooks (15) are evenly distributed at the four corners of the box culvert precast segments (1).

5. The prefabricated wet-jointing construction method for drainage box culverts under airport non-stop height restriction as described in claim 1, characterized in that: The construction of the foundation layer (5) in S3 includes: S31: Testing the bearing capacity of the foundation in the foundation trench (4). If the bearing capacity of the foundation does not meet the requirements, over-excavation is carried out; S32: After the bearing capacity of the foundation meets the requirements, an 8-12cm thick crushed stone foundation layer is laid in the foundation trench (4); S33: A 10cm thick concrete foundation layer is poured on the crushed stone foundation layer. A 2m straightedge and feeler gauge are used for measurement. The maximum value is taken for 3 consecutive measurements. The flatness of the concrete foundation layer is controlled to not exceed the standard requirement of 5mm.

6. The prefabricated wet-jointing construction method for drainage box culverts under airport non-stop height restriction as described in claim 1, characterized in that: The construction of the positioning structure (6) includes: S41: according to the width of the box culvert, measuring and laying out lines on both sides of the cushion layer (5) to form two positioning lines; S42: fixing the construction segment positioning piles (61) at the positions of the positioning lines on both sides: the positioning piles (61) set symmetrically on the left and right are a group, and at least two groups are fixed on both sides of each box culvert.

7. The prefabricated wet-jointing construction method for drainage box culverts under airport non-stop height restriction as described in claim 6, characterized in that: The top of the positioning pile (61) facing the precast box culvert section (1) is processed into a guide slope (611), and the bottom of the positioning pile (61) facing the precast box culvert section (1) is processed into a positioning vertical plane (612). The outer side of the positioning vertical plane (612) is flush with the positioning line.

8. The prefabricated wet-jointing construction method for drainage box culverts under airport non-stop height restriction as described in claim 1, characterized in that: The post-cast strip reinforcement (2) of two adjacent precast box culvert sections (1) in S3 is lapped and tied with stirrups (7).

9. The prefabricated wet-jointing construction method for drainage box culverts under airport non-stop height restriction as described in claim 1, characterized in that: The walking module (81) is a track wheel mechanism. The support module (82) includes a support plate (821) connected between the two track wheel mechanisms, a seat (822) for workers to sit on, and a height adjustment component (823) installed between the support plate (821) and the seat (822). The height adjustment component (823) and the track wheel mechanism are both connected to the control module to adjust the height of the seat (822) as the workers work.

10. The prefabricated wet-jointing construction method for drainage box culverts under airport non-stop height restriction as described in claim 9, characterized in that: The support module (82) includes two units respectively located on both sides, so that two workers can carry out construction on both sides at the same time.

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