Integral box culvert assembly line construction process

Abstract

The invention relates to the technical field of box culvert prefabricated part production, in particular to an integral box culvert assembly line construction technology which comprises the steps that preparation before construction is conducted, specifically, technical preparation, personnel preparation, material preparation and mechanical equipment preparation are conducted, and condition guarantee is provided for formal box culvert production; processing the steel bars into a steel bar cage, storing the steel bar cage and waiting for entering a mold; after the mold is installed in place, the mold is cleaned, debugged, maintained and regularly inspected; preparation work before concrete pouring, mold cleaning, oil coating, steel bar mold entering and embedded part mounting are conducted; pouring concrete; performing natural or steam curing; the box culvert is demoulded, and components are marked; the box culvert is stored and watered for maintenance; a single-circulation assembly line is adopted, box culvert production stations are arranged, all procedures of box culvert production are dynamically completed clockwise, the occupied area is reduced, meanwhile, production management and material transportation are facilitated, the production efficiency is improved, and the space utilization rate is increased.

Description

Technical Field

[0001] The invention relates to the technical field of box culvert prefabricated part production, and in particular to an integral box culvert assembly line construction process. Background Art

[0002] At present, there are many construction processes for prefabricated box culverts. Limited by the existing process and process characteristics, the current production mainly adopts the fixed mold fixed pedestal method. First, the fixed pedestal is cast with concrete in the prefabrication yard. After the strength of the fixed pedestal reaches the design requirements, the bottom formwork is installed on the fixed pedestal, the steel bars are tied, and the side formwork is assembled to form a fixed mold. Concrete is poured and maintained to complete the prefabrication of the box culvert. After hoisting to the storage area, the next box culvert is prefabricated. In the production process using the fixed mold fixed pedestal method, a large number of side formworks are required, the assembly time is long, the production efficiency is low, and a large number of fixed pedestals are required, which occupies a large area of ​​the production site. Summary of the invention

[0003] The purpose of the present invention is to solve the shortcomings of the prior art and to propose an integral box culvert assembly line construction process.

[0004] In order to achieve the above object, the present invention adopts the following technical solutions: An integral box culvert assembly line construction process, comprising: Step S1, pre-construction preparation, including technical preparation, personnel preparation, material preparation and mechanical equipment preparation, to provide conditions and guarantees for the formal production of box culverts; Step S2, the steel bars are processed into steel cages, and the steel cages are stored and wait for mold entry; Step S3: Inspection of the mold upon arrival, transportation and hoisting, cleaning, debugging, maintenance and regular inspection after the mold is installed in place; Step S4, preparation work before concrete pouring, mold cleaning, oiling, steel bar placement, embedded parts installation; Step S5, after checking and screening the concrete raw materials, mix them, check the concrete again after mixing, and pour after the inspection and acceptance is qualified; Step S6: natural or steam curing; Step S7, the box culvert is demoulded and the components are marked. Demolding can be performed only when the surface temperature is within 20°C of the outside temperature; Step S8: storage and watering maintenance of the box culvert.

[0005] Preferably, in step S1, the technical preparation includes the review of the box culvert design drawings, the formulation of the mold plan, the construction and installation of the production line, the preparation and approval of the construction plan, the clarification of the technical requirements of various material specifications and models, and the test work related to the concrete mix ratio, so as to provide accurate and effective technical guarantee for the formal production of the box culvert; The materials prepared for box culvert production include steel bar raw materials, concrete materials, embedded parts and auxiliary materials. Before the box culvert is produced, the model specifications and technical quality requirements of each material should be clearly defined according to the design and specification requirements. A material procurement plan should be made before and during construction to prepare materials and supplies for production. To ensure the stability of the box culvert quality, all raw materials should not be frequently replaced by different manufacturers.

[0006] Preferably, in step S2, the steel bar skeleton is made in the following specific steps: A. The assembly and welding of the steel frame are carried out on a template that meets the design; B. Use CO2 protected spot welding to weld. The welding is based on the standard of ensuring that the welding point is firm and does not damage the main reinforcement. The surrounding area is fully welded, and the interior requires at least spot welding. No leakage welding or false welding is allowed. There are no pores or slag inclusions on the surface of the welding point. C. No more than two longitudinal stress-bearing steel bars with joints shall be used in the same steel bar skeleton, and they shall not be arranged adjacent to each other. The yield strength ratio of the longitudinal stress-bearing steel bars shall not be greater than 1.30; D. When welding is used for connection, test welding shall be carried out according to the grade, diameter and performance of the steel bar and mass production shall be carried out only after the welding parameters are determined and the skeleton welding points meet the design requirements; E. Mark the steel bar skeletons that have passed the inspection to facilitate use in the next process.

[0007] Preferably, if the steel bar skeleton has any of the following conditions, it is an unqualified steel bar skeleton, is not allowed to enter the mold, and needs to be scrapped or reworked: ①The grade, diameter, number and spacing of the steel bars do not conform to the drawings; ② There is oil stain, particles or flakes of old rust on the surface of the steel bar; ③ The steel bar skeleton is deformed and welded; ④ The number and position of the main reinforcement do not conform to the drawings or violate the requirements of the quality acceptance standards.

[0008] Preferably, in step S3, the mold must undergo three-stage testing before it is officially put into the box culvert production, including: processing and assembly accuracy testing, accuracy retesting after the mold is transported to the site and positioned, and comparison testing of the mold accuracy after trial production with the actual accuracy; Before pouring concrete each time, the mold should be routinely inspected to confirm whether it can be used. If it exceeds the scope of use, it should be repaired in time. After each set of molds has been used for a period of time, a systematic inspection must be carried out to ensure the mold's accuracy requirements.

[0009] Preferably, in step S4, the step of placing the steel bar skeleton into the mold body comprises: a. After the steel cage is processed in the steel processing plant, the finished steel cage is hoisted into the mold by a crane; b. Before entering the mold, fix the concrete pad on the frame. The protective layer pad meets the design requirements and the thickness of the main reinforcement protective layer is 30mm; c. When using a door to lift the mold, use a special lifting device, with the hook close to the longitudinal reinforcement with stirrups, and lower it vertically from the top of the bottom template. It must not slide on the bottom template; d. After entering the mold, check the thickness of the protective layer on the inner mold side and the bottom. It must not be used when the protective layer is larger than the tolerance or the steel cage is twisted.

[0010] Preferably, in step S5, the specific pouring steps are: a. The mixing station transports the concrete to the transport hopper through a torpedo tank. The tester determines whether it is necessary to sample the batch of concrete. Only when the slump of the concrete is confirmed to be within the allowable range can the concrete be poured; then the concrete is poured into the mold using the concrete distribution hopper; Concrete mold requirements: The time from concrete discharge to mold entry shall not exceed 2 hours, and the longest shall not exceed 3 hours; the minimum mold entry temperature shall not be less than 10°C, and the maximum temperature shall not be greater than 30°C; b. Concrete is evenly distributed in a clockwise direction along the mold from one side of the box culvert. The layer thickness is not more than 50cm, and the slump should be controlled at 180±20mm. During the material feeding process, the attached vibrator is started to vibrate the concrete, and a vibrating rod is used for auxiliary vibration; Reserve grouting holes and replace rubber pads with good sealing at connector positions to ensure that there will be no leakage during concrete pouring; c. Concrete finishing: There are three procedures for finishing concrete: rough, medium and fine. For the rough finishing, use a scraper to scrape and remove excess concrete or fill in depressions, and then perform rough grinding. For the medium finishing, use a putty spoon to finish the concrete after the water is absorbed, so that the box culvert concrete surface is flat and smooth. For the fine finishing, use a long spoon to carefully smooth it to ensure that the surface is bright and free of dust marks.

[0011] Preferably, in step S6, in order to prevent the expansion of various components of concrete and damage to the internal structure due to the increase in temperature, the curing temperature is 45°C to 55°C, the maximum temperature does not exceed 60°C, the heating and cooling speed shall not exceed 15°C per hour, and the working condition of the central temperature controller is observed every half an hour and adjusted when necessary.

[0012] Preferably, the integral box culvert assembly line includes a production line, a ferry line and a steam-curing kiln. The production line and the ferry line are perpendicular to each other. There are two groups of ferry lines, which are respectively arranged at both ends of the production line. The ferry line is located in a sinking pit. The production line and the steam-curing kiln are both provided with conveying tracks, and a material placing machine is provided on the production line.

[0013] Preferably, a translation trolley is provided on the upper side of the ferry line, the translation trolley includes a mold trolley and a ferry trolley, the mold trolley includes a bearing platform and a vehicle base, a pressure sensor is provided between the bearing platform and the vehicle base, and the ferry trolley includes a reference platform and a positioner; A limiting track is arranged on the upper side of the reference platform, the limiting track is matched with the conveying track, the vehicle base is in sliding contact with the limiting track, and the reference platform is in sliding connection with the ferry line.

[0014] Compared with the prior art, the present invention has the following beneficial effects: 1. The present invention adopts a single-cycle assembly line, arranges box culvert production stations, and dynamically completes each process of box culvert production in a clockwise manner, thereby reducing floor space, facilitating production management and material transportation, improving production efficiency, and increasing space utilization; 2. The mold and box culvert of the present invention are loaded with a mold trolley and moved longitudinally along the production line. At the same time, a ferry trolley is configured to realize the lateral movement of the mold trolley, switch the production line or maintenance line, improve the convenience of mold transportation, reduce the number of times the mold or box culvert is lifted, avoid damage to the box culvert structure, and effectively ensure the yield rate. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 A schematic diagram of the production site distribution and work efficiency of an integral box culvert assembly line construction process proposed by the present invention; Figure 2 A schematic diagram of the assembly line layout of an integral box culvert assembly line construction process proposed by the present invention; Figure 3 A production process flow chart of an integral box culvert assembly line construction process proposed by the present invention; Figure 4 A schematic diagram of an assembly line operation station of an integral box culvert assembly line construction process proposed by the present invention; Figure 5 A schematic diagram of the three-dimensional structure of the ferry station of the assembly line of the integral box culvert assembly line construction process proposed by the present invention; Figure 6 The present invention provides a schematic diagram of the three-dimensional structure of a shuttle bus for the construction process of an integral box culvert assembly line.

[0016] In the figure: 1. Production line; 2. Translation trolley; 21. Carrying platform; 22. Warning light; 23. Car base; 24. Limiting track; 25. Reference platform; 26. Positioner; 3. Ferry line; 4. Steaming kiln. DETAILED DESCRIPTION

[0017] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, rather than all the embodiments. The following description of at least one exemplary embodiment is actually only illustrative and is by no means intended to limit the present invention and its application or use. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0018] Reference Figure 1-6 , an integral box culvert assembly line construction process, comprising: Step S1, pre-construction preparation, including technical preparation, personnel preparation, material preparation and mechanical equipment preparation, to provide conditions and guarantees for the formal production of box culverts; a. Technical preparation, which includes the review of box culvert design drawings, the formulation of mold plans, the construction and installation of production lines, the preparation and approval of construction plans, the clarification of technical requirements for various material specifications and models, and tests related to concrete mix ratios, to provide accurate and effective technical support for the formal production of box culverts; b. Personnel preparation: In order to complete the box culvert production task with high quality and efficiency, in addition to allocating relevant management personnel, we also train front-line workers and reasonably allocate personnel of different types and numbers according to production requirements; c. Material preparation. Box culvert production includes steel bar raw materials, concrete materials (supplied by mixing station), embedded parts and auxiliary materials. Before the production of box culvert, the specifications and technical quality requirements of each material should be clearly defined according to the design and specification requirements. A material procurement plan should be made before and during the construction process to prepare materials for production. In order to ensure the stability of the box culvert quality, all raw materials should not be frequently replaced by other manufacturers; d. Preparation of mechanical equipment. The investment in mechanical equipment should be matched and reasonably combined, and the quantity should meet the requirements of the project progress and safety, quality and environmental protection standards. Full consideration should be given to the stability and practicality of the operation of mechanical equipment, and brands with excellent quality, stable performance, energy conservation, safety and reliability should be selected. The power should be able to meet the needs and leave room for expansion without generating waste. The equipment's integrity rate and the impact of other unforeseen factors should be taken into consideration to increase sufficient spare capacity.

[0019] Step S2, the steel bars are processed into steel cages, and the steel cages are stored and wait for mold entry; Steel bar processing includes raw material acceptance, straightening and cutting, steel bar forming, and finally binding and welding into a skeleton; Before welding steel bars, the rust, water scale and oil stains on the welded parts must be removed, and the twisted parts of the steel bar ends must be straightened or cut off; after welding, the weld surface must be smooth without defects such as burns and cracks; Specific steps for making steel frame: A. The assembly and welding of the steel frame are carried out on a template that meets the design; B. Use CO2 protected spot welding to weld. The welding is based on the standard of ensuring that the welding point is firm and does not damage the main reinforcement. The surrounding area is fully welded, and the interior requires at least spot welding. No leakage welding or false welding is allowed. There are no pores or slag inclusions on the surface of the welding point. C. No more than two longitudinal stress-bearing steel bars with joints shall be used in the same steel bar skeleton, and they shall not be arranged adjacent to each other. The yield strength ratio of the longitudinal stress-bearing steel bars shall not be greater than 1.30; D. When welding is used for connection, test welding shall be carried out according to the grade, diameter and performance of the steel bar and mass production shall be carried out only after the welding parameters are determined and the skeleton welding points meet the design requirements; E. Mark the steel bar skeletons that have passed the inspection to facilitate use in the next process.

[0020] Steel bars are placed and waiting to be put into the mold: The lower part of the steel cage is stored with 8 150*150mm square timber blocks, with a vertical spacing of 1.5m between the lower blocks, for a total of 8 square timbers; Avoid damaging the mold when the skeleton is put into the mold. The protective layer of each part of the skeleton must meet the design requirements after entering the mold. The net distance between the steel bar and the adjacent embedded parts and embedded holes must be at least 20mm. During the transportation of the steel skeleton or the pouring of concrete, ensure that the steel skeleton does not change position. The operator shall use the steel skeleton with inspection mark and check whether the mark is consistent with the template model; if any of the following conditions occurs, the steel skeleton shall not be allowed to enter the template and shall be scrapped or reworked: ①The grade, diameter, number and spacing of the steel bars do not conform to the drawings; ② There is oil stain, particles or flakes of old rust on the surface of the steel bar; ③ The steel bar skeleton is deformed and welded; ④ The number and position of the main reinforcement do not conform to the drawings or violate the requirements of the quality acceptance standards.

[0021] Step S3: Inspection of the mold upon arrival, transportation and hoisting, cleaning, debugging, maintenance and regular inspection after the mold is installed in place; The mold is made by high-precision mechanical mold. The accuracy of the finished box culvert is guaranteed by the accuracy of mold processing and closing and vibrating. Therefore, the mold must undergo three-stage testing before it is officially put into box culvert production; Processing and assembly accuracy testing, precision retesting of molds after transportation and positioning, and comparison testing of mold accuracy after trial production with actual accuracy; All test indicators must be within the standard allowable tolerance before normal production can be put into operation; The mold is divided into two stages: factory acceptance and site acceptance: Mould inspection: The inspection items are calipers, steel tape measures, feeler gauges and angle squares, and the inspection is carried out according to the contract and accuracy requirements. Both parties determine the time when the mould is shipped from the manufacturer to the construction site for installation and commissioning. The factory acceptance cannot be used as the final acceptance, which is to prevent the mould from deformation and damage during transportation. The construction site acceptance is determined as the final acceptance of the mould.

[0022] Mould transportation: The mold components should be kept horizontal and pressure-free during transportation to ensure the correctness and stability of the reinforcement. If the positioning is unstable, it will cause collision and deformation during transportation; Mould hoisting: A. Correct hoisting method is an important factor to ensure the quality of mold installation; carefully check the hoisting equipment, wire rope, and hook before hoisting, and make sure they are in good condition before hoisting; B. During the hoisting process, the important parts of the mold should not be subjected to stress, because from its structure, it can be seen that the stress at the hinge position will cause the deformation of the entire tube mold; C. During the hoisting process, use a parallel hoisting device to hoist it to the installation position. The part where the hoisting device contacts the tube mold is the position that does not affect the mold accuracy. When doing this work, there must be factory personnel on site to confirm the hoisting method and hoisting position.

[0023] Mould cleaning: After the mold is in place, when it is opened for the first time, use diesel or gasoline to remove the protective layer, clean the mold surface with cotton yarn, and use a plastic scraper to clean the dirt; blow the mold clean with compressed air; count the mold accessories, and open the four side panels of the mold to clean the inner surface of the mold and adjust the bolts.

[0024] Mould debugging: During the debugging process, carefully open and close the side molds, and tighten the bolts strictly according to the operating procedures and the required tightening torque; Mould acceptance: The mold acceptance process usually includes two contents: mold appearance defect detection and mold accuracy index detection; a. Mould appearance defect detection mainly involves visually observing whether the mould has obvious collisions, local roughness, curling and other defects; b. Accuracy index detection is to check the processing of the mold by measuring tools according to the drawing size and mold production requirements; mainly including the following contents: ① Width: detected by vernier caliper; ② Thickness: detected by steel ruler; ③ Side panel joint width, detected by feeler gauge; c. Carry out quality inspection on newly-arrived models one by one, conduct quality inspection on the box culverts produced for the first time, and make relevant records of the inspection results; Measures to ensure mold accuracy: Apply lubricating oil to the threads of bolts, and remove concrete slag from the assembly parts of the mold and the inner cavity of the mold to ensure accurate mold size and smooth operation; when opening and closing the mold, avoid garbage and dust from entering the joints of the base and side panels; in order to prevent the mold from being scratched or deformed, be careful not to place or drop heavy objects on the mold; avoid hitting with a hammer or crowbar, and make sure the tightness of the bolts when closing and removing the mold; Before pouring concrete each time, the mold should be routinely checked to confirm whether it can be used. If it exceeds the scope of use, it should be repaired in time. After each set of molds has been used for a period of time, for example, every 1 month, a systematic inspection must be carried out to ensure the accuracy requirements of the mold.

[0025] The inspection items include: mold width diagonal, inner cavity height; whether there is damage inside the mold that affects the precision; whether the mold parts are damaged or missing. Only after the problems in the above items are solved can the mold be approved to be put back into production; When testing the finished box culvert, if defects caused by molds are found, the relevant molds should be tested and checked immediately; Maintenance of molds: After using the mold, shovel away the ash and clean it up, remove the moisture in the mold, and use lubricating oil to prevent rust. The mold storage place must avoid rain and moisture, and the mold must be placed horizontally. If the mold is not used temporarily, clean the inner cavity, apply anti-rust protective film, and cover it with canvas. Regular mold inspection: Under normal production conditions, two types of mold inspection management are implemented, namely, quick inspection before pouring and regular mold inspection; The mold accuracy inspection is carried out by laser 3D scanning every 100 rings per week; regular mold inspection is to ensure that the mold is within the allowable tolerance for box culvert production; under normal circumstances, the inspection cycle is tentatively set at monthly; if there are special circumstances, the inspection cycle can be shortened or targeted inspections can be carried out; any excess should be reported and corrected in a timely manner, and the box culvert production can continue only after the re-inspection meets the standards.

[0026] Step S4, preparation work before concrete pouring, mold cleaning, oiling, steel bar placement, embedded parts installation; 1. Clean the mold ① Loosen the fixing screws of the side mold and arrange each piece in order.

[0027] ② In order to protect the smooth surface of the inner side of the template, it is strictly forbidden to use metal knives to clean the scale on the inner surface.

[0028] ③ Use a brush to clean the bottom, surroundings and supports of the template.

[0029] ④ Carefully check whether the sealing ring (standard rubber strip) of the template is installed in place and its cleanliness.

[0030] ⑤ Carefully check and lubricate all moving parts.

[0031] ⑥ Pay attention to strictly clean the surface dirt at the template joints to ensure accuracy.

[0032] ⑦ The outer surface of the template and the adjusting bolts should always be kept clean.

[0033] 2. Oiling Use a sprayer and a clean rag to apply the release oil inside the mold. Apply the release oil evenly to avoid insufficient or excessive release oil.

[0034] 3. Enter the mold After the steel cage is processed and inspected, it is transported to the production workshop for storage, and then the steel cage is hoisted into the mold using a special hoist. Before hoisting into the mold, the protective layer support stool and flywheel are installed at the bottom and four sides of the steel cage according to the specified positions. During the hoisting period, attention must be paid to whether the steel cage is deformed. If there is a problem, it must not be used and the supervisor must be notified to handle it.

[0035] The positioning steel bars are encrypted, the protective layer pads are encrypted and fixed firmly, so that the qualified rate of the steel bar protective layer meets the quality engineering requirements.

[0036] The steps of inserting the steel bar skeleton into the mold body include: a. After the steel cage is processed in the steel processing plant, the finished steel cage is hoisted into the mold by a crane; b. Before entering the mold, the concrete pad should be fixed on the frame, the protective layer pad should meet the design requirements, and the thickness of the main reinforcement protective layer should be 30mm; c. When using a door to lift the mold, use a special lifting device, with the hook close to the longitudinal reinforcement with stirrups, and lower it vertically from the top of the bottom template. It must not slide on the bottom template; d. After entering the mold, check the thickness of the protective layer on the inner mold side and the bottom. If the protective layer is larger than the tolerance or the steel cage is twisted, it shall not be used; 4. Pre-embedded Arrange and tie the steel bar components and embedded accessories, and install the embedded parts and reserved holes fixed on the formwork firmly without any omissions; Position the steel cage, and place the hand hole former and pre-buried PVC pipe at the designated positions according to the model and specifications of the mold. Seal both ends of the pre-buried pipe with rubber plugs to prevent leakage. After the steel bars and embedded parts are installed, self-inspection is performed to ensure that the production and installation quality of embedded parts meet the design requirements, all embedded bolt holes are unobstructed, and the inner surface is flat. Each process can only proceed to the next process after passing the inspection. If it fails, return to step S2 for inspection and rework; 5. Mould closing ① First close the inner mold, and the torque reaches the operating requirements; ② Close the outer side mold; tighten the tension screws and the screws between the outer mold plate to make it perpendicular to the bottom mold; ③ Connect the inner mold and the outer mold with tension screws to ensure the thickness of the component; ④ Verify the closure of the template by checking the marks on the corners of the side template; 6. Acceptance The quality inspector conducts the final inspection before pouring, including the thickness of the protective layer, mold cleanliness, steel cage model, and the number and location of embedded parts. After the inspection and acceptance are qualified, the next process will be carried out.

[0037] Step S5, pouring concrete; The main materials used in prefabricated box culvert concrete are: cement is P.O42.5, fly ash is F grade I, S95 grade slag powder, coarse aggregate is 5-25mm, fine aggregate is river sand, and the water-binder ratio of concrete is 0.36. Before pouring concrete, the raw materials need to be tested, and only qualified ones can be used for subsequent concrete mixing; After concrete mixing, it is necessary to conduct an inspection. Before concrete pouring, relevant concrete performance indicators such as slump and mold temperature should be strictly controlled, and a certain number of standard curing test blocks should be made; When vibrating concrete, the vibration time of each point on the surface except the bottom arc surface is controlled within 30 seconds, and the rod lifting time is 18 seconds, for a total of 48 seconds; Label the vibrating rod and mark it at 60cm, 70cm and 80cm to ensure that the contact surface of the upper and lower layers can be vibrated. Keep the vibrating rod 50-100mm away from the side form and insert it 50-100mm into the lower concrete. The sign of compaction is that the concrete stops sinking, no more bubbles emerge, and the surface becomes flat and slurry. After each vibration is completed, slowly pull out the vibrating rod while vibrating to avoid collision with the formwork, steel bars and other embedded parts. Specific pouring steps: a. The mixing station transports the concrete to the transport hopper through a torpedo tank. The tester determines whether it is necessary to sample the batch of concrete. Only when the slump of the concrete is confirmed to be within the allowable range can the concrete be poured; then the concrete is poured into the mold using the concrete distribution hopper; Concrete mold requirements: The time from concrete discharge to mold entry shall not exceed 2 hours, and the longest shall not exceed 3 hours; the minimum mold entry temperature shall not be less than 10°C, and the maximum temperature shall not be greater than 30°C; b. Concrete is evenly distributed in a clockwise direction along the mold from one side of the box culvert. The layer thickness is not more than 50cm, and the slump should be controlled at 180±20mm. During the material feeding process, the attached vibrator is started to vibrate the concrete, and a vibrating rod is used for auxiliary vibration; Reserve grouting holes and replace rubber pads with good sealing at connector positions to ensure that there will be no leakage during concrete pouring; c. Concrete finishing: There are three procedures for finishing concrete: rough, medium and fine. For the rough finishing, use a scraper to scrape and remove excess concrete (or fill in depressions), and then perform rough grinding. For the medium finishing, use a putty spoon to finish the concrete after the water is absorbed, so that the box culvert concrete surface is flat and smooth. For the fine finishing, use a long spoon to carefully smooth it to ensure that the surface is bright and free of dust marks.

[0038] Step S6: natural or steam curing; The steam curing of the box culvert of the production line is carried out in a special closed, heat-insulated curing room. The curing room follows the requirements of steam curing heating, constant temperature and cooling. After the daily construction volume is completed, all the cast molds enter the curing kiln for curing at different stages. The curing system includes heat source, temperature sensor and temperature controller. In order to prevent the expansion of various components of concrete and damage to the internal structure due to rising temperature, the steaming temperature is 45℃~55℃, the maximum temperature does not exceed 60℃, and the heating and cooling rate shall not exceed 15℃ per hour. A dedicated person shall be responsible for steaming control, observe the working condition of the central temperature controller every half hour, and make adjustments when necessary.

[0039] Step S7, removing the mold of the box culvert and marking the components; After the box culvert is steam-cured, the compressive strength of the specimen cured under the same conditions reaches 60% of the design strength (the specific value needs to be confirmed by the designer), and demoulding can be carried out only when the surface temperature is within 20°C of the outside temperature difference; it is strictly forbidden to pry or knock hard during demoulding to avoid damaging the components and molds; after opening the mold, use special lifting equipment and flexible lifting belts to lift the components in a scooping manner; before lifting, move slowly and steadily to prevent improper operation from damaging the components or molds; Box culvert marking: After the box culvert is demoulded, the marking personnel will mark each box culvert with marks that are difficult to erase, such as the production date, manufacturing number, and box culvert type.

[0040] Step S8, storage and watering maintenance of the box culvert; A. Box culvert stacking After the box culvert is transported to the yard, it is lifted vertically to the stacking area with a special lifting device for storage. The stacking of box culverts should not exceed 3 layers, and square wood is used between layers. The distance between adjacent box culverts should not be less than 1m; B. Maintenance during the stacking stage The box culverts are piled in the yard and maintained by spraying water with a spray truck to ensure that the surface is moist before the box culvert reaches its age. The stacking and maintenance period is not less than 14 days. At least one water storage tank is set up in a single yard to collect rainwater and surface water during the maintenance process, which is collected, precipitated and filtered before recycling.

[0041] The integral box culvert assembly line includes a production line 1, a ferry line 3 and a steaming kiln 4. The production line 1 and the ferry line 3 are perpendicular to each other. The ferry line 3 is provided with two groups, which are respectively arranged at the two ends of the production line 1. The ferry line 3 is located in a sinking pit. The production line 1 and the steaming kiln 4 are both provided with conveying tracks. A material placing machine is provided on the production line 1. A translation trolley 2 is provided on the upper side of the ferry line 3. The translation trolley 2 includes a mold trolley and a ferry trolley. The mold trolley includes a bearing platform 21 and a vehicle base 23. A pressure sensor is provided between the bearing platform 21 and the vehicle base 23. The pressure sensor is used to detect the placement status of the mold on the upper side of the bearing platform 21. If there is a tilt or collision, the pressure sensor will detect the pressure change. At the same time, it is used to detect the concrete pouring status, accurately measure the amount of concrete pouring, and assist the work of the material placing machine. A warning light 22 is provided on the side of the bearing platform 21. The control panel receives the pressure sensor signal and controls the warning light 22 to light up or change color to indicate the pressure change at that part. The ferry trolley includes a reference platform 25 and a positioner 26. The positioner 26 is used to determine the position of the reference platform 25, so as to facilitate the mold trolley to access the conveying track. A limit track 24 is provided on the upper side of the reference platform 25. The limit track 24 is adapted to the conveying track on the upper side of the production line 1. The vehicle base 23 is in sliding contact with the limit track 24, and the reference platform 25 is slidably connected to the ferry line 3. The box culvert assembly line adopts a clockwise single-cycle method. The mold is loaded on the mold trolley, and the mold trolley moves on production line 1 to complete the processes of mold cleaning, mold release agent application, steel cage mold insertion, mold assembly, embedded parts installation and concrete pouring. After pouring is completed, the mold trolley pushes the mold onto the right ferry trolley and runs to the finishing station to complete the finishing.

[0042] The ferry trolley moves the mold trolley and the mold above to the steaming kiln 4 line according to the demand. After the doors of the steaming kiln 4 on both sides are opened, the mold trolley pushes the mold after static curing into the steaming kiln 4. The mold trolley is pushed forward by the jack, and the mold trolley out of the kiln is taken over by the ferry trolley on the left; The ferry trolley on the left runs to the demolding station to complete the demolding and lifting work, complete the box culvert demolding, and move the ferry trolley until the mold trolley returns to production line 1 to continue the next round of mold cleaning, steel cage placement, embedded parts placement, steam curing line concrete pouring, and concrete curing. The above method completes the cycle of the mold over and over again.

[0043] The above description is only a preferred specific implementation manner of the present invention, but the protection scope of the present invention is not limited thereto. Any technician familiar with the technical field can make equivalent replacements or changes according to the technical scheme and inventive concept of the present invention within the technical scope disclosed by the present invention, which should be covered by the protection scope of the present invention.

[0044] It should be noted that the terms used herein are only for describing specific embodiments and are not intended to limit the exemplary embodiments according to the present application. As used herein, unless the context clearly indicates otherwise, the singular form is also intended to include the plural form. In addition, it should be understood that when the terms "comprise" and / or "include" are used in this specification, it indicates the presence of features, steps, operations, devices, components and / or combinations thereof.

[0045] Unless otherwise specifically stated, the relative arrangement of the parts and steps described in these embodiments, numerical expressions and numerical values ​​do not limit the scope of the present invention. At the same time, it should be understood that, for ease of description, the sizes of the various parts shown in the accompanying drawings are not drawn according to the actual proportional relationship. The technology, method and equipment known to ordinary technicians in the relevant field may not be discussed in detail, but in appropriate cases, the technology, method and equipment should be regarded as a part of the authorization specification. In all examples shown and discussed here, any specific value should be interpreted as being merely exemplary, rather than as a limitation. Therefore, other examples of exemplary embodiments may have different values. It should be noted that similar reference numerals and letters represent similar items in the following drawings, so once a certain item is defined in an accompanying drawing, it does not need to be further discussed in subsequent drawings.

Claims

1. An integral box culvert assembly line construction process, characterized in that: include: Step S1, pre-construction preparation, including technical preparation, personnel preparation, material preparation and mechanical equipment preparation, to provide conditions and guarantees for the formal production of box culverts; Step S2, the steel bars are processed into steel cages, and the steel cages are stored and wait for mold entry; Step S3: Inspection of the mold upon arrival, transportation and hoisting, cleaning, debugging, maintenance and regular inspection after the mold is installed in place; Step S4, preparation work before concrete pouring, mold cleaning, oiling, steel bar placement, embedded parts installation; Step S5, after checking and screening the concrete raw materials, mix them, check the concrete again after mixing, and pour after the inspection and acceptance is qualified; Step S6: natural or steam curing; Step S7, the box culvert is demoulded and the components are marked. Demolding can be performed only when the surface temperature is within 20°C of the outside temperature; Step S8: storage and watering maintenance of the box culvert.

2. The integral box culvert assembly line construction process according to claim 1 is characterized in that: In step S1, the technical preparation includes the review of the box culvert design drawings, the formulation of the mold plan, the construction and installation of the production line, the preparation and approval of the construction plan, the clarification of the technical requirements of various material specifications and models, and the test work related to the concrete mix ratio, so as to provide accurate and effective technical guarantee for the formal production of the box culvert; The materials prepared for box culvert production include steel bar raw materials, concrete materials, embedded parts and auxiliary materials. Before the box culvert is produced, the model specifications and technical quality requirements of each material should be clearly defined according to the design and specification requirements. A material procurement plan should be made before and during construction to prepare materials and supplies for production. To ensure the stability of the box culvert quality, all raw materials should not be frequently replaced by different manufacturers.

3. The integral box culvert assembly line construction process according to claim 1 is characterized in that: In step S2, the specific steps of making the steel frame are: A. The assembly and welding of the steel frame are carried out on a template that meets the design; B. Use CO2 protected spot welding to weld. The welding is based on the standard of ensuring that the welding point is firm and does not damage the main reinforcement. The surrounding area is fully welded, and the interior requires at least spot welding. No leakage welding or false welding is allowed. There are no pores or slag inclusions on the surface of the welding point. C. No more than two longitudinal stress-bearing steel bars with joints shall be used in the same steel bar skeleton, and they shall not be arranged adjacent to each other. The yield strength ratio of the longitudinal stress-bearing steel bars shall not be greater than 1.30; D. When welding is used for connection, test welding shall be carried out according to the grade, diameter and performance of the steel bar and mass production shall be carried out only after the welding parameters are determined and the skeleton welding points meet the design requirements; E. Mark the steel bar skeletons that have passed the inspection to facilitate use in the next process.

4. The integral box culvert assembly line construction process according to claim 3 is characterized in that: If the steel bar skeleton has any of the following conditions, it is an unqualified steel bar skeleton and is not allowed to be put into the mold and needs to be scrapped or reworked: ①The grade, diameter, number and spacing of the steel bars do not conform to the drawings; ② There is oil stain, particles or flakes of old rust on the surface of the steel bar; ③ The steel bar skeleton is deformed and welded; ④ The number and position of the main reinforcement do not conform to the drawings or violate the requirements of the quality acceptance standards.

5. The integral box culvert assembly line construction process according to claim 1 is characterized in that: In step S3, the mold must undergo three stages of testing before it is officially put into the production of box culverts, including: processing and assembly accuracy testing, accuracy retesting after the mold is transported to the site and positioned, and comparison testing of the mold accuracy after trial production with the actual accuracy; Before pouring concrete each time, the mold should be routinely inspected to confirm whether it can be used. If it exceeds the scope of use, it should be repaired in time. After each set of molds has been used for a period of time, a systematic inspection must be carried out to ensure the mold's accuracy requirements.

6. The integral box culvert assembly line construction process according to claim 1 is characterized in that: In step S4, the step of inserting the steel bar skeleton into the mold body includes: a. After the steel cage is processed in the steel processing plant, the finished steel cage is hoisted into the mold by a crane; b. Before entering the mold, fix the concrete pad on the frame. The protective layer pad meets the design requirements and the thickness of the main reinforcement protective layer is 30mm; c. When using a door to lift the mold, use a special lifting device, with the hook close to the longitudinal reinforcement with stirrups, and lower it vertically from the top of the bottom template. It must not slide on the bottom template; d. After entering the mold, check the thickness of the protective layer on the inner mold side and the bottom. It must not be used when the protective layer is larger than the tolerance or the steel cage is twisted.

7. The integral box culvert assembly line construction process according to claim 1 is characterized in that: In step S5, the specific pouring steps are: a. The mixing station transports the concrete to the transport hopper through a torpedo tank. The tester determines whether it is necessary to sample the batch of concrete. Only when the slump of the concrete is confirmed to be within the allowable range can the concrete be poured; then the concrete is poured into the mold using the concrete distribution hopper; Concrete mold requirements: The time from concrete discharge to mold placement shall not exceed 2 hours, and the longest shall not exceed 3 hours; The minimum mold temperature shall not be less than 10°C, and the maximum temperature shall not be greater than 30°C; b. Concrete is evenly distributed in a clockwise direction along the mold from one side of the box culvert. The layer thickness is not more than 50cm, and the slump should be controlled at 180±20mm. During the material feeding process, the attached vibrator is started to vibrate the concrete, and a vibrating rod is used for auxiliary vibration; Reserve grouting holes and replace rubber pads with good sealing at connector positions to ensure that there will be no leakage during concrete pouring; c. Concrete finishing: There are three procedures for finishing concrete: rough, medium and fine. For the rough finishing, a scraper is used to scrape and remove excess concrete or fill in depressions, and then rough grinding is performed. For the medium finishing, a putty spoon is used to finish the concrete after the water is absorbed, so that the concrete surface of the box culvert is flat and smooth. Use a long spoon to smooth the polished surface to ensure a bright surface without any dust marks.

8. The integral box culvert assembly line construction process according to claim 1 is characterized in that: In step S6, in order to prevent the expansion of various components of concrete and damage to the internal structure due to the increase in temperature, the steam curing temperature is 45°C to 55°C, the maximum temperature does not exceed 60°C, the heating and cooling speed shall not exceed 15°C per hour, and the working condition of the central temperature controller is observed every half an hour and adjusted when necessary.

9. The integral box culvert assembly line construction process according to claim 1 is characterized in that: The integrated box culvert assembly line comprises a production line (1), a ferry line (3) and a steaming kiln (4); the production line (1) and the ferry line (3) are perpendicular to each other, and the ferry line (3) is provided with two groups, which are respectively arranged at two ends of the production line (1); The ferry line (3) is located in the sinking pit, the production line (1) and the steaming kiln (4) are both provided with conveying tracks, and the production line (1) is provided with a material distribution machine.

10. The integral box culvert assembly line construction process according to claim 9, characterized in that: A translation trolley (2) is provided on the upper side of the ferry line (3), the translation trolley (2) comprises a mold trolley and a ferry trolley, the mold trolley comprises a bearing platform (21) and a vehicle base (23), a pressure sensor is provided between the bearing platform (21) and the vehicle base (23), and the ferry trolley comprises a reference platform (25) and a positioner (26); A limiting rail (24) is provided on the upper side of the reference platform (25), the limiting rail (24) is adapted to the conveying rail, the vehicle base (23) is in sliding contact with the limiting rail (24), and the reference platform (25) is slidably connected to the ferry line (3).

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