Construction technology of whole segment prefabricated installation assembled box culvert

Abstract

The application relates to a whole-segment prefabricated installation assembly type box culvert construction process and relates to the technical field of culvert construction, which comprises the following steps: a culvert segment pre-production area construction step, a steel bar processing and installation step, a horizontal culvert segment prefabrication step, a culvert segment concrete pouring step, a field foundation construction step, a culvert segment storage and transportation step and a culvert segment overturning step, wherein the culvert segment overturning step needs to adopt a clasp ring matched with a pulley to form a fixed pulley set, so that the overturning of the culvert segment can be facilitated; compared with field pouring, the whole construction step can reduce material waste, reduce engineering quantity, save labor, reduce cost, easily control and improve engineering quality.

Description

Technical Field

[0001] This application relates to the field of culvert construction technology, and in particular to a construction process for prefabricated and assembled box culverts of whole segments. Background Technology

[0002] Currently, with the rapid development of my country's economy, the continuous increase in the scale of trade and transportation and the number of motor vehicles, the proportion of high-grade highway construction in infrastructure construction is increasing year by year.

[0003] Regarding the aforementioned technologies, the inventors believe that culverts, as the main form of crossing highways, generally adopt on-site steel reinforcement binding, formwork erection, and concrete pouring construction processes. These processes involve long construction times, a large amount of wet work, a long concrete curing time, and the inability to backfill after trenching. They are also greatly affected by weather conditions, making it difficult to control construction quality and posing significant risks to personal and property safety. Summary of the Invention

[0004] In order to improve the difficulties in culvert construction and quality control, the purpose of this application is to provide a prefabricated and assembled box culvert construction process.

[0005] The technical solution for the prefabricated and assembled box culvert construction process of whole segment provided in this application is as follows: A construction process for prefabricated and assembled box culverts consisting of a single segment includes the following steps: Construction steps of the culvert prefabrication area: The surface of the prefabrication site is first compacted and leveled by rolling, and then divided into a culvert storage area and a culvert prefabrication area. A gravel cushion layer is laid in the culvert storage area, and concrete is poured on the surface of the culvert prefabrication area for hardening treatment. Rebar processing and installation steps: In the rebar processing yard, make the telescopic rebar jig and rebar. After making them, transport them to the culvert section prefabrication area, place the rebar on the telescopic rebar jig for welding and binding, and at the same time, embed the culvert section lifting rings during the rebar installation and connection to make a rebar skeleton. Prefabrication steps for horizontal culvert sections: The culvert section formwork uses standardized steel formwork, which consists of three parts: outer formwork, inner formwork, and bottom formwork. When assembling the culvert section formwork, the inner formwork is first installed inside the steel reinforcement cage, and then the steel reinforcement cage is hoisted and positioned as a whole. Then, outer steel reinforcement protective layer pads are set on the outside of the steel reinforcement cage, and then the outer formwork is installed on the outside of the steel reinforcement cage. Culvert concrete pouring steps: Pour concrete into the formwork, and then vibrate the concrete in the formwork using an immersion vibrator; when using an immersion vibrator, the moving distance should not exceed 1.5 times the effective radius of the vibrator, and the vibrator should be 5cm to 10cm away from the side formwork; insert the vibrator into the lower layer of concrete 5cm to 10cm to ensure that the two layers of concrete are fully bonded, remove the immersion vibrator after vibration, and cover and water the culvert after the grout has settled, with a curing period of 7 days; On-site foundation construction steps: Excavation of the foundation pit will be carried out simultaneously with the prefabrication of culvert sections. The foundation pit construction should be synchronized with the culvert section prefabrication schedule to prevent waterlogging after excavation. Excavation of the foundation pit should only begin after the basic prefabrication of the culvert sections is completed. Over-excavation is strictly prohibited. Mechanical excavation should leave a 20cm margin before reaching the base, followed by manual excavation to the design elevation. If over-excavation occurs, loose parts should be removed before further treatment of the base. Culvert section storage and transportation steps: When the concrete strength of the culvert section reaches 85% or more of the design strength, the culvert section is lifted to the culvert section storage area using a gantry crane; when loading, the culvert section is lifted onto the transport vehicle using a gantry crane; after the culvert section is transported to the site, it is first lifted to a level site in a horizontal position, with rubber tire supports underneath. Culvert section overturning steps: The crane uses a T-shaped lifting head with anti-disengagement devices at both ends. Steel wire ropes are then hung on both sides of the T-shaped lifting head, and a U-shaped shackle is fitted under each steel wire rope. A pulley is installed on the pin of the U-shaped shackle, and a section of steel wire rope is hung on the pulley. The lower end of the steel wire rope hanging on the pulley is connected to the lifting ring pre-embedded in the top plate of the culvert section to form a fixed pulley group. Then, the crane is started to overturn the culvert section. Culvert section installation steps: After the previous culvert section is hoisted into place, apply waterstop strips and sealant to the contact surface of the culvert section. Then, mark a line along the direction of the end of the previous culvert section as a reference for the installation of the next culvert section. Then, connect each culvert section according to the direction of the marked line.

[0006] By adopting the above-mentioned technical solutions, compared with on-site casting, precast culverts save energy, reduce material waste, decrease the amount of work, save labor, and lower costs. Using mechanized installation combined with minimal manual labor saves a significant amount of labor, resulting in substantial overall economic benefits. Furthermore, culvert section production and on-site assembly are carried out simultaneously, in a streamlined construction process with a high degree of mechanization, thus reducing worker labor intensity, increasing efficiency, and speed. Standardized construction operations ensure high-quality engineering. The standardized management and mechanized assembly line operation of culvert section prefabrication and installation make it easy to control and improve project quality.

[0007] Optionally, in the construction steps of the culvert prefabrication area, the prefabrication site is leveled by bulldozer, and then compacted by a 20T vibratory roller. A 20cm gravel cushion layer is laid in the culvert storage area, and the culvert prefabrication area is hardened with 10cm thick C20 concrete. A 12mm nominal diameter threaded steel bar is installed under the culvert prefabrication platform.

[0008] By adopting the above technical solutions, the hardening treatment of the prefabricated culvert section area can make the storage of the culvert section more stable and safe, and it is less likely to cause the culvert section to collapse or be damaged due to subsidence.

[0009] Optionally, during the construction steps of the culvert prefabrication area, drainage ditches may be pre-installed when the prefabrication site is hardened.

[0010] By adopting the above technical solutions, the drainage ditch can drain rainwater in a timely manner during the rainy season, avoiding the accumulation of rainwater in the culvert prefabrication area and preventing corrosive damage to the culvert sections.

[0011] Optionally, in the culvert section concrete pouring step, the concrete pouring should be carried out at the most favorable time of day; that is, during summer construction, the concrete pouring of the culvert section should be carried out in the morning or evening when the temperature is lower, avoiding the high temperature period of noon and afternoon; during winter construction, it should be carried out during the time of day when the temperature is higher, that is, in the morning or at noon, avoiding the time period of evening and before and after sunrise.

[0012] By adopting the above technical solutions, construction can be carried out when the temperature is low in summer or high in winter, allowing the concrete to solidify under better temperature conditions, which can reduce the occurrence of construction joints to a certain extent.

[0013] Optionally, in the culvert section flipping step, the T-shaped lifting head includes a horizontal bearing beam and a vertical lifting beam, with the vertical lifting beam vertically positioned in the middle of the horizontal bearing beam; the anti-disengagement device includes a pressing and closing mechanism and a contact alarm mechanism; the pressing and closing mechanism is installed on the horizontal bearing beam, and the contact alarm mechanism is installed on the vertical lifting beam; a positioning groove is provided on the upper surface of the horizontal bearing beam for the insertion of a wire rope; after the wire rope is pressed into the positioning groove, the pressing and closing mechanism automatically closes the end of the horizontal bearing beam under the pressure of the wire rope; when the wire rope is removed from the positioning groove or no pressure is applied to the positioning groove, the pressing and closing mechanism automatically opens the end of the horizontal bearing beam; and the contact alarm mechanism automatically alarms when the end of the horizontal bearing beam is open and automatically cuts off power when the end of the horizontal bearing beam is closed.

[0014] By adopting the above technical solution, when the wire rope is in the positioning groove and the T-shaped lifting head begins to lift, the weight of the culvert section will force the wire rope to press against the positioning groove, thereby causing the pressing and closing mechanism to automatically close the end of the transverse bearing beam. At this time, the end of the transverse bearing beam is in a closed state, and the contact alarm mechanism will not sound an alarm, indicating that the wire rope has been stably placed in the positioning groove. If the wire rope slides out of the positioning groove without applying pressure to the positioning groove, the pressing and closing mechanism will automatically open the end of the transverse bearing beam, and the contact alarm mechanism will sound an alarm, reminding the on-site personnel that the wire rope is not properly secured. This allows the personnel to promptly detect the installation status of the wire rope for subsequent lifting work of the culvert section.

[0015] Optionally, the pressing and closing mechanism includes a pressing block, a horizontal pushing block, and an abutting block; a first vertical channel is vertically formed below the positioning groove in the transverse bearing beam, and the pressing block is slidably inserted into the first vertical channel; a transverse channel is horizontally formed in the transverse bearing beam, the transverse channel being perpendicular to and communicating with the first vertical channel, and the horizontal pushing block is slidably inserted into the transverse channel; a second vertical channel is vertically formed near the end of the transverse bearing beam, and the second vertical channel is also far from the first vertical channel. One end of a vertical channel is vertically connected, and the abutment block is vertically slidably inserted into the second vertical channel; the pressing block and the horizontal pushing block, as well as the abutment block and the horizontal pushing block, are all in contact with each other through inclined abutment surfaces. When the pressing block moves vertically downward, the horizontal pushing block is displaced in the transverse channel and pushes the abutment block to move vertically upward; a connecting beam is horizontally arranged on the vertical lifting beam, and a docking block is arranged on the connecting beam directly above the abutment block. After the abutment block moves upward and fits with the docking block, it closes the end of the transverse bearing beam.

[0016] By adopting the above technical solution, after the wire rope is in the positioning groove, when the T-shaped lifting head turns the culvert section, the wire rope will be subjected to tension and this tension will be converted into pressure and applied to the pressing block. This causes the pressing block to be pushed vertically downward in the first vertical channel. After the pressing block moves downward, under the action of the inclined abutment surface, it will push the horizontal pushing block to the side closer to the abutment block. The abutment block will then be pushed upward under the action of the inclined abutment surface, causing the abutment block to move vertically upward in the second vertical channel. Finally, after contacting the connecting block, it will close the end of the transverse bearing beam, thus achieving a more convenient effect of closing the end of the transverse bearing beam.

[0017] Optionally, one side of the first vertical channel, the second vertical channel, and the transverse channel is provided with an elastic cavity along its own direction. The pressing block, the horizontal pushing block, and the abutting block are all provided with protrusions that extend into the elastic cavity. A spring is provided between each protrusion and the end wall of the elastic cavity. The spring on the pressing block side always has the tendency to push the pressing block vertically upward. The spring on the horizontal pushing block side always has the tendency to push the horizontal pushing block horizontally towards the pressing block. The spring on the abutting block side always has the tendency to push the abutting block vertically downward.

[0018] By adopting the above technical solution, when it is not necessary to hoist the culvert section, the wire rope no longer applies pressure to the pressing block, or the wire rope can be directly removed from the positioning groove. The spring near the abutment block drives the abutment block to move vertically downward, squeezing the horizontal pushing block. The spring near the horizontal pushing block will drive the horizontal pushing block to move closer to the pressing block side, and it has a tendency to move into the first vertical channel. Finally, the pressing block will be pushed vertically upward by the thrust and the pushing force brought by the spring. Since the abutment block moves downward, the end of the transverse bearing beam will be in the open state, thereby achieving the effect of automatically opening the end of the transverse bearing beam when the culvert section is not being hoisted, and also making it convenient to remove the wire rope from the T-shaped lifting head.

[0019] Optionally, the contact alarm device includes a power-on alarm mechanism and a power supply mechanism; the power supply mechanism is installed on the connecting beam, and the power-on alarm mechanism is installed on the vertical suspension beam. The power supply mechanism is used to supply electrical energy to the power-on alarm mechanism when the contact block and the docking block abut against each other. The power-on alarm mechanism is used to emit a warning sound after power is applied and to turn off the warning sound after power is cut off.

[0020] By adopting the above technical solution, when the abutting block and the connecting block abut against each other, the end of the transverse bearing beam is closed, and the power-on alarm mechanism does not sound an alarm, indicating that the wire rope is normally positioned in the positioning groove. If the abutting block and the connecting block no longer abut against each other and separate, the end of the transverse bearing beam is open, and the power-on alarm mechanism sounds an alarm, indicating that the wire rope is not normally positioned in the positioning groove. This means that the position of the wire rope needs to be readjusted, and normal hoisting cannot be carried out. This achieves the effect of timely detection of incorrect wire rope position and thus avoiding the inability to properly hoist the wire rope during subsequent culvert section hoisting.

[0021] Optionally, the power supply mechanism includes a mounting block, a battery, and a hinge rod; the mounting block is disposed at the end of the connecting beam, and a storage cavity is formed inside the mounting block, in which the battery is placed; a sliding cavity is formed at the lower end of the storage cavity on the mounting block, and the docking block is slidably inserted into the sliding cavity; a through-hole is vertically formed on the side wall of the sliding cavity, and a stop rod extending out of the through-hole is provided on the side wall of the docking block near the top; the hinge rod is hinged to the connecting beam, and the end of the stop rod is connected to one end of the hinge rod by a tension spring; the power alarm mechanism includes... The device includes an alarm and a conductive block. The alarm is mounted on a vertical suspension beam, and the conductive block is mounted on the side of the vertical suspension beam near the hinge rod, and the conductive block is electrically connected to the alarm. A conductive plate is provided at the end of the hinge rod away from the tension spring, and the conductive plate is electrically connected to the battery. When the abutting block abuts against the mating block and moves vertically upward in the sliding cavity, the end of the hinge rod away from the tension spring tilts downward, causing the conductive plate to separate from the conductive block. When the abutting block no longer abuts against the mating block, causing the mating block to move vertically downward in the sliding cavity, the hinge rod is in a horizontal state, causing the conductive plate to adhere to the conductive block.

[0022] By adopting the above technical solution, when the abutting block contacts the mating block from bottom to top and pushes the mating block to move vertically upward, the abutting rod will pull one end of the hinge rod to tilt upward, thereby causing the other end of the hinge rod with the conductive plate to tilt downward and separate from the conductive block. At this time, the battery cannot supply power to the alarm, and the alarm will stop emitting an alarm sound after the power is cut off. When the abutting block moves vertically downward and separates from the mating block, the mating block falls naturally under the action of gravity, driving the abutting rod to move vertically downward, thereby causing the abutting rod to pull one end of the hinge rod from the tilted upward state to the horizontal state. At this time, the conductive plate and the conductive block re-adhere, the battery supplies power to the alarm, and the alarm sound re-emerges. Ultimately, the effect of controlling the alarm sound according to the opening and closing of the end of the transverse bearing beam is achieved.

[0023] Optionally, in the culvert joint installation step, a two-component polysulfide sealant is used for the sealant, and a water-swellable waterstop is used for the waterstop strip.

[0024] By adopting the above technical solution, the two-component polysulfide sealant is a Class B Grade I building polysulfide sealant with self-adhesive properties to concrete and based on liquid polysulfide rubber, which is vulcanized at room temperature and has the ability to seal joints and stop water leakage. The water-swellable waterstop strip expands and deforms 2-3 times when it comes into contact with water, and fills all irregular surfaces, cavities and gaps in the joint, while generating huge contact pressure, which can prevent leakage to a large extent.

[0025] In summary, this application includes at least one of the following beneficial technical effects: 1. Compared to on-site casting, precast culverts save energy, reduce material waste, decrease the amount of work, save labor, and lower costs. Using mechanized installation combined with minimal manual labor saves significant labor, resulting in substantial overall economic benefits. Furthermore, culvert production and on-site assembly are carried out simultaneously, in a streamlined construction process with a high degree of mechanization, leading to lower labor intensity, higher efficiency, and faster speed for workers. Standardized construction operations ensure high-quality engineering. The standardized management and mechanized assembly line operation of culvert precasting and installation make it easier to control and improve project quality. 2. Once the wire rope is in the positioning groove, when the T-shaped lifting head begins hoisting, the weight of the culvert section will force the wire rope to press against the positioning groove, causing the pressing and closing mechanism to automatically close the end of the transverse load-bearing beam. At this time, the end of the transverse load-bearing beam is in a closed state, and the contact alarm mechanism will not sound, indicating that the wire rope is stably positioned in the positioning groove. If the wire rope slides out of the positioning groove without applying pressure to it, the pressing and closing mechanism will automatically open the end of the transverse load-bearing beam, and the contact alarm mechanism will sound an alarm, reminding the on-site personnel that the wire rope is not properly secured. This allows the personnel to promptly detect the installation status of the wire rope for subsequent hoisting work of the culvert section. Attached Figure Description

[0026] Figure 1 This is a flowchart illustrating an embodiment of this application; Figure 2 This is a partial cross-sectional view of an embodiment of this application, used to illustrate the T-shaped auger; Figure 3 This is a partial cross-sectional view illustrating the press-to-close mechanism according to an embodiment of this application; Figure 4 This is a partial cross-sectional view of an embodiment of the present application, used to illustrate the contact alarm mechanism.

[0027] In the diagram: 1. T-shaped lifting head; 2. Horizontal bearing beam; 21. Positioning groove; 22. First vertical channel; 23. Horizontal channel; 24. Second vertical channel; 3. Vertical lifting beam; 31. Connecting beam; 32. Connecting block; 321. Abutting rod; 4. Anti-disengagement device; 5. Press-to-close mechanism; 51. Pressing block; 52. Horizontal pushing block; 53. Abutting block; 6. Contact alarm mechanism; 61. Power-on alarm mechanism; 611. Alarm; 612. Conductive block; 62. Power supply mechanism; 621. Mounting block; 6211. Storage cavity; 6212. Sliding cavity; 6213. Through-hole; 622. Battery; 623. Hinge rod; 6231. Conductive sheet; 7. Inclined abutting surface; 8. Elastic cavity; 81. Spring; 9. Protrusion. Detailed Implementation

[0028] The following is in conjunction with the appendix Figure 1 -Appendix Figure 4 This application will be described in further detail below.

[0029] A construction process for prefabricated and assembled box culverts in whole segments, combined with Figure 1 , 2 This includes the following steps: Construction steps for culvert prefabrication area: First, the surface of the prefabrication site is compacted and leveled using a 20T vibratory roller. The site is divided into a culvert storage area and a culvert prefabrication area. A 20cm thick gravel cushion layer is laid in the culvert storage area. A 10cm thick C20 concrete layer is poured on the surface of the culvert prefabrication area for hardening. A 12mm nominal diameter threaded steel bar is installed under the culvert prefabrication platform. Finally, drainage ditches are pre-installed during the hardening of the prefabrication site to drain rainwater in a timely manner during rainy days. Rebar processing and installation steps: In the rebar processing yard, a telescopic rebar jig and rebars are fabricated. To ensure accuracy, semi-finished rebars are processed using a CNC bending machine within the yard. The rebar jig is made of materials with sufficient strength and rigidity. During fabrication, attention is paid to the accuracy of the rebar positions; the diameter of the rebars in the culvert section must be considered when positioning them. During rebar processing, the cutting length for staggered joint positions is considered to ensure that the number of joints in the same cross-section of the compressed rebar is less than 50%. After fabrication, the rebars are transported to the culvert section prefabrication area, where they are placed on the telescopic rebar jig for welding and binding. Because the prefabrication posture of the culvert section is at a 90° angle to the installation posture, four lifting rings are added to the top of the culvert section to facilitate on-site rotation. Finally, a rebar skeleton is formed. Prefabrication steps for horizontal culvert sections: The culvert section formwork uses standardized steel formwork, which consists of three parts: outer formwork, inner formwork, and bottom formwork. When assembling the culvert section formwork, the inner formwork is first installed inside the steel reinforcement cage. Then, the steel reinforcement cage is hoisted and positioned as a whole. Inner layer steel reinforcement protective layer spacers are first set inside the steel reinforcement cage, and then outer layer steel reinforcement protective layer spacers are set outside the steel reinforcement cage. The strength of the protective layer spacers shall not be lower than the strength of the concrete of the culvert body itself. Finally, the outer formwork is installed on the outside of the steel reinforcement cage. Culvert concrete pouring steps: The concrete uses the C40 concrete mix proportion approved by the central laboratory, is centrally mixed at the batching plant, and transported by concrete mixer trucks. Before unloading, it should be mixed using a high-speed rotary mixer for no less than 20 seconds, followed by concrete performance testing and data recording. Concrete pouring should only proceed after confirming that all properties meet the requirements. Pouring should be done in layers and continuously, with a pouring time not exceeding 3 hours, and should not exceed the initial setting time of the concrete to prevent construction joints. Concrete pouring should be carried out at the most favorable time of day. In summer, the concrete pouring of the box culvert should be carried out in the cooler mornings and evenings, avoiding the high temperatures of midday and afternoon. In winter, the pouring should be carried out during the warmer periods of the day, preferably in the morning or midday, avoiding the evening and the period around sunrise. Immersion vibrators are mainly used for compacting the culvert concrete. When pouring concrete, the distribution should be uniform, and the thickness of each layer should not exceed 30cm. The concrete placement speed should be coordinated with the vibration. The vibration time should be until the concrete stops settling, no more air bubbles appear, and the surface is flat and covered with slurry. When using an immersion vibrator, the moving distance should not exceed 1.5 times the vibrator's radius of action, and the vibrator should be 5cm to 10cm away from the side formwork. The vibrator should be inserted 5cm to 10cm into the lower layer of concrete to ensure full bonding between the two layers. After each section of vibration is completed, the vibrator should be slowly withdrawn while still vibrating to avoid collisions with the formwork, reinforcing bars, and other embedded parts. Close observation is crucial during construction to prevent under-vibration, missed vibration, or over-vibration. After the concrete is poured, it should be covered and watered for curing after the slurry has settled. The curing period is 7 days. Curing should be done by wrapping with a thin film and then covering with geotextile, keeping the curing surface continuously moist. Alternating between dry and wet curing is prohibited. On-site foundation construction steps: Excavation of the foundation pit will be carried out simultaneously with the prefabrication of culvert sections. The excavation progress must be coordinated with the prefabrication schedule to prevent waterlogging after excavation. Excavation should only begin after the culvert sections are largely prefabricated. Over-excavation is strictly prohibited. Mechanical excavation should leave a 20cm margin before reaching the base, followed by manual excavation to the design elevation. If over-excavation occurs, loose parts should be removed before further treatment of the base. It is important to note that before concrete foundation construction, the soil bearing capacity must be tested. Once the bearing capacity meets design requirements, a 50cm gravel cushion layer should be constructed, compacted, and solidified before proceeding with the C25 concrete foundation construction. The concrete foundation should be 20cm thick and 20cm wider on each side than the culvert body. During concrete foundation construction, the direction of the culvert's drainage slope must be considered. After completion, the surface should be flat and free of pits to meet the requirements for culvert section installation. Culvert section storage and transportation steps: When the concrete strength of the culvert section reaches 85% or more of the design strength, the culvert section is lifted to the culvert section storage area using a gantry crane; when loading, the culvert section is lifted onto the transport vehicle using a gantry crane; after the culvert section is transported to the site, it is first lifted to a level site in a horizontal position, with rubber tire supports underneath. Culvert section overturning steps: The crane uses a T-shaped lifting head 1, with anti-disengagement devices 4 at both ends of the T-shaped lifting head 1. Steel wire ropes are then hung on both sides of the T-shaped lifting head 1, and a U-shaped shackle is fitted under each steel wire rope. A pulley is installed on the pin of the U-shaped shackle, and a section of steel wire rope is hung on the pulley. The lower end of the section of steel wire rope hanging on the pulley is connected to the lifting ring pre-embedded in the top plate of the culvert section to form a fixed pulley group. Then, the crane is started to overturn the culvert section. Culvert section installation steps: After the previous culvert section is hoisted into place, apply waterstop strips and sealant to the contact surface of the culvert section. Then, mark a line along the direction of the end of the previous culvert section as a reference for the installation of the next culvert section. Then, connect each culvert section according to the direction of the marked line.

[0030] The challenge of on-site hoisting and tilting lies in ensuring that the four wire ropes on the lifting ring are simultaneously stressed during the tilting process, guaranteeing safety. After multiple deliberations and research with the on-site professional hoisting unit, it was determined that a fixed pulley system consisting of shackles and pulleys would be used. Using this method, during the tilting of the culvert section, the length and angle of the wire ropes are dynamically adjusted via the fixed pulleys, ensuring that all four points are simultaneously stressed, and that the force direction remains vertically upward. This avoids oblique forces during tilting, preventing crane instability and potential hazards. It also effectively solves the problem of friction between the wire ropes and the shackles during culvert section orientation changes. Compared to on-site casting, precast culverts reduce material waste, decrease the amount of work, save labor, and lower costs. Using mechanized installation combined with minimal manual labor saves significant labor, resulting in substantial overall economic benefits. Furthermore, culvert section production and on-site assembly are carried out simultaneously, in a streamlined construction process with a high degree of mechanization, resulting in low labor intensity, high efficiency, and fast speed for workers. Standardized construction operations ensure high-quality engineering. The prefabrication and installation of culvert sections are carried out in accordance with standardized management and mechanized assembly line operations, which makes it easy to control and improve the quality of the project.

[0031] like Figure 2 , 3 As shown, the T-shaped lifting head 1 includes a horizontal bearing beam 2 and a vertical lifting beam 3, with the vertical lifting beam 3 vertically positioned in the middle of the horizontal bearing beam 2. The anti-disengagement device 4 includes a pressing and closing mechanism 5 and a contact alarm mechanism 6. The pressing and closing mechanism 5 is installed on the horizontal bearing beam 2, and the contact alarm mechanism 6 is installed on the vertical lifting beam 3. A positioning groove 21 is provided on the upper surface of the horizontal bearing beam 2, which is used for hooking a wire rope. After the wire rope is pressed into the positioning groove 21, the pressing and closing mechanism 5 automatically closes the end of the horizontal bearing beam 2 under the pressure of the wire rope. When the wire rope is removed from the positioning groove 21 or no pressure is applied to the positioning groove 21, the pressing and closing mechanism automatically opens the end of the horizontal bearing beam 2. The contact alarm mechanism 6 automatically alarms when the end of the horizontal bearing beam 2 is open and automatically cuts off power when the end of the horizontal bearing beam 2 is closed.

[0032] During the culvert section flipping process, the alarm principle is as follows: When the wire rope is in the positioning groove 21, if the hoisting action of the culvert section is started, the wire rope will definitely be subjected to the tension from the culvert section. The wire rope will be tightly pressed into the positioning groove 21. At this time, the end of the transverse bearing beam 2 is in a closed state, and the contact alarm mechanism 6 does not emit an alarm sound, indicating that the wire rope is in the correct position and the culvert section can be hoisted normally. However, if the wire rope is not in the positioning groove 21, it indicates that the wire rope is in an incorrect position and the culvert section cannot be hoisted. Moreover, at this time, the transverse bearing beam 2 is also in an open state, and the contact alarm mechanism 6 will emit an alarm sound to remind the on-site personnel.

[0033] Combination Figure 2 , 3 The pressing and closing mechanism 5 includes a pressing block 51, a horizontal pushing block 52, and an abutting block 53; a first vertical channel 22 is vertically opened in the transverse bearing beam 2 below the positioning groove 21, and the pressing block 51 is slidably inserted into the first vertical channel 22; a transverse channel 23 is horizontally opened in the transverse bearing beam 2, the transverse channel 23 is perpendicular to and connected to the first vertical channel 22, and the horizontal pushing block 52 is slidably inserted into the transverse channel 23; a second vertical channel 24 is vertically opened in the transverse bearing beam 2 near the end, and the second vertical channel 24 is also away from the first vertical channel 23. One end of the channel 22 is vertically connected, and the abutment block 53 is vertically slidably inserted into the second vertical channel 24; the pressing block and the horizontal pushing block 52, and the abutment block 53 and the horizontal pushing block 52 are all attached to each other through the inclined abutment surface 7. When the pressing block 51 moves vertically downward, the horizontal pushing block 52 is displaced in the transverse channel 23 and pushes the abutment block 53 to move vertically upward; a connecting beam 31 is horizontally arranged on the vertical hanging beam 3, and a docking block 32 is arranged on the connecting beam 31 directly above the abutment block 53. After the abutment block 53 moves upward and attaches with the docking block 32, it closes the end of the transverse bearing beam 2.

[0034] like Figure 2 , 3 As shown, one side of the first vertical channel 22, the second vertical channel 24, and the transverse channel 23 is provided with an elastic cavity 8 along its own direction. The pressing block 51, the horizontal pushing block 52, and the abutting block 53 are all provided with protrusions 9 that extend into the elastic cavity 8. A spring 81 is provided between each protrusion 9 and the end wall of the elastic cavity 8. The spring 81 located on the side of the pressing block 51 always has the tendency to push the pressing block 51 vertically upward. The spring 81 located on the side of the horizontal pushing block 52 always has the tendency to push the horizontal pushing block 52 horizontally towards the pressing block 51. The spring 81 located on the side of the abutting block 53 always has the tendency to push the abutting block 53 vertically downward.

[0035] When the wire rope is in the positioning groove 21 and the culvert section is being hoisted, the wire rope, suspending the culvert section, applies pressure to the pressing block 51, forcing the pressing block 51 to move vertically downward. In this embodiment, the pressing block 51 and the horizontal pushing block 52 initially form an L-shape. Both ends of the pressing block 51 and the horizontal pushing block 52 are provided with inclined contact surfaces, and the inclination angles of the two inclined contact surfaces are both 45°, thus forming a right angle. When the pressing block 51 is pressed down, it will directly push the horizontal pushing block 52 to one side. The horizontal push block 52 is pushed away horizontally; the other end of the horizontal push block 52 and the abutment block 53 are initially L-shaped, and the inclined contact surfaces between the horizontal push block 52 and the abutment block 53 are also at 45°; the horizontal push block 52, which is pushed by the force, will push the abutment block 53 vertically upward, so that the abutment block 53 contacts the docking block 32, and finally closes the end of the transverse bearing beam 2; that is, as long as the position of the wire rope is correctly in the positioning groove 21, the end of the transverse bearing beam 2 will automatically close during the hoisting of the culvert section.

[0036] However, when the wire rope is not in the positioning groove 21, the pressing block 51 will move vertically upward under the elastic force of the spring 81, and the horizontal pushing block 52 will also reset under the elastic force of the spring 81 and move horizontally towards the first vertical channel 22. Finally, the abutting block 53 will move vertically downward under the action of gravity and the elastic force of the spring 81, and the abutting block 53 will separate from the connecting block 32. The end of the transverse bearing beam 2 will be in an open state. That is, as long as the wire rope is not in the positioning groove 21, the end of the transverse bearing beam 2 will automatically open.

[0037] Reference Figure 2 , 4The contact alarm device includes a power-on alarm mechanism 61 and a power supply mechanism 62. The power supply mechanism 62 is installed on the connecting beam 31, and the power-on alarm mechanism 61 is installed on the vertical hanging beam 3. The power supply mechanism 62 is used to supply electrical energy to the power-on alarm mechanism 61 when the abutting block 53 abuts against the connecting block 32. The power-on alarm mechanism 61 is used to emit a warning sound after power is applied and to turn off the warning sound after power is cut off. Specifically, the power supply mechanism 62 includes a mounting block 621, a battery 622, and a hinge rod 623. The mounting block 621 is located at the end of the connecting beam 31. A storage cavity 6211 is formed inside the mounting block 621, and the battery 622 is placed inside the storage cavity 6211. A sliding cavity 6212 is formed at the lower end of the storage cavity 6211 on the mounting block 621, and the docking block 32 is slidably inserted into the sliding cavity 6212. A through hole 6213 is vertically formed on the side wall of the sliding cavity 6212. A stop rod 321 extending from the through hole 6213 is provided on the side wall of the docking block 32 near the top. The hinge rod 623 is hinged to the connecting beam 31 via a vertical rod, and the end of the stop rod 321 is connected to one end of the hinge rod 623 via a tension spring. (Power-on alarm) The structure 61 includes an alarm 611 and a conductive block 612. The alarm 611 is mounted on the vertical lifting beam 3, and the conductive block 612 is mounted on the side of the vertical lifting beam 3 near the hinge rod 623, and the conductive block 612 is electrically connected to the alarm 611. A conductive sheet 6231 is provided at the end of the hinge rod 623 away from the tension spring, and the conductive sheet 6231 is electrically connected to the battery 622. When the abutting block 53 abuts against the mating block 32 and moves vertically upward in the sliding cavity 6212, the end of the hinge rod 623 away from the tension spring tilts downward and separates the conductive sheet 6231 from the conductive block 612. When the abutting block 53 no longer abuts against the mating block 32 and the mating block 32 moves vertically downward in the sliding cavity, the hinge rod 623 is in a horizontal state and the conductive sheet 6231 is in contact with the conductive block 612.

[0038] When the abutment block 53 abuts against the mating block 32 from bottom to top and pushes the mating block 32 to move vertically upward, the abutment rod 321 will pull one end of the hinge rod 623 to tilt upward, thereby causing the other end of the hinge rod 623 with the conductive plate 6231 to tilt downward and separate from the conductive block 612. At this time, the battery 622 cannot supply power to the alarm 611, and the alarm 611 will stop emitting an alarm sound after the power is cut off. When the abutment block 53 moves vertically downward and separates from the mating block 32, the mating block 32 falls naturally under the action of gravity, driving the abutment rod 321 to move vertically downward, thereby causing the abutment rod 321 to pull one end of the hinge rod 623 from the tilted upward state to the horizontal state. At this time, the conductive plate 6231... 31 is reattached to the conductive block 612, and the battery 622 supplies power to the alarm 611. The alarm 611 then sounds again, ultimately achieving the effect of controlling the alarm 611 to sound according to the opening and closing of the end of the transverse bearing beam 2. That is, when the wire rope is not in the positioning groove 21, the position of the surface wire rope is inaccurate. At this time, the alarm 611 will sound to alert the on-site personnel, and the end of the transverse bearing beam 2 will open to facilitate the adjustment or removal of the wire rope. When the wire rope is in the positioning groove 21, the position of the surface wire rope is accurate, the alarm 611 will not sound, and the end of the transverse bearing beam 2 will be in a closed state.

[0039] The embodiments described in this specific implementation are preferred embodiments of this application and are not intended to limit the scope of protection of this application. Identical components are represented by the same reference numerals. Therefore, all equivalent changes made to the structure, shape, and principle of this application should be covered within the scope of protection of this application.

Claims

1. A construction process for prefabricated and assembled box culverts, characterized in that, Includes the following steps: Construction steps of the culvert prefabrication area: The surface of the prefabrication site is first compacted and leveled by rolling, and then divided into a culvert storage area and a culvert prefabrication area. A gravel cushion layer is laid in the culvert storage area, and concrete is poured on the surface of the culvert prefabrication area for hardening treatment. Rebar processing and installation steps: In the rebar processing yard, make the telescopic rebar jig and rebar. After making them, transport them to the culvert section prefabrication area, place the rebar on the telescopic rebar jig for welding and binding, and at the same time, embed the culvert section lifting rings during the rebar installation and connection to make a rebar skeleton. Prefabrication steps for horizontal culvert sections: The culvert section formwork uses standardized steel formwork, which consists of three parts: outer formwork, inner formwork, and bottom formwork. When assembling the culvert section formwork, the inner formwork is first installed inside the steel reinforcement cage, and then the steel reinforcement cage is hoisted and positioned as a whole. Then, outer steel reinforcement protective layer pads are set on the outside of the steel reinforcement cage, and then the outer formwork is installed on the outside of the steel reinforcement cage. Culvert concrete pouring steps: Pour concrete into the formwork, and then vibrate the concrete in the formwork using an immersion vibrator; when using an immersion vibrator, the moving distance should not exceed 1.5 times the effective radius of the vibrator, and the vibrator should be 5cm to 10cm away from the side formwork; insert the vibrator into the lower layer of concrete 5cm to 10cm to ensure that the two layers of concrete are fully bonded, remove the immersion vibrator after vibration, and cover and water the culvert after the grout has settled, with a curing period of 7 days; On-site foundation construction steps: Excavation of the foundation pit will be carried out simultaneously with the prefabrication of culvert sections. The foundation pit construction should be synchronized with the culvert section prefabrication schedule to prevent the foundation pit from being submerged in water after excavation. Excavation of the foundation pit should only begin after the culvert sections are basically completed. Over-excavation is strictly prohibited during foundation pit excavation. Mechanical excavation should leave a 20cm margin before reaching the base, followed by manual excavation to the design elevation. If over-excavation occurs, any loose parts should be removed before treating the base. Culvert section storage and transportation steps: When the concrete strength of the culvert section reaches 85% or more of the design strength, the culvert section is lifted to the culvert section storage area using a gantry crane; when loading, the culvert section is lifted onto the transport vehicle using a gantry crane; after the culvert section is transported to the site, it is first lifted to a level site in a horizontal position, with rubber tire supports underneath. Culvert section flipping steps: The crane uses a T-shaped lifting head (1), and anti-disengagement devices (4) are installed at both ends of the T-shaped lifting head (1). A steel wire rope is hung on both sides of the T-shaped lifting head (1). A U-shaped clasp is fitted under each steel wire rope. A pulley is installed on the pin of the U-shaped clasp. Another steel wire rope is hung on the pulley. The lower end of the other steel wire rope hung on the pulley is connected to the lifting ring pre-embedded in the top plate of the culvert section to form a fixed pulley group. Then the crane is started to flip the culvert section. Culvert section installation steps: After the previous culvert section is hoisted into place, apply waterstop strips and sealant to the contact surface of the culvert section. Then, mark a line along the direction of the end position of the previous culvert section as a reference for the installation of the next culvert section. Then, connect each culvert section according to the direction of the marked line. In the culvert section flipping step, the T-shaped lifting head (1) includes a horizontal bearing beam (2) and a vertical lifting beam (3), the vertical lifting beam (3) being vertically arranged in the middle of the upper surface of the horizontal bearing beam (2); the anti-disengagement device (4) includes a pressing and closing mechanism (5) and a contact alarm mechanism (6); the pressing and closing mechanism (5) is installed on the horizontal bearing beam (2), and the contact alarm mechanism (6) is installed on the vertical lifting beam (3); a positioning groove (21) is provided on the upper surface of the horizontal bearing beam (2), the positioning groove (21) being used for the wire rope to be hooked in; The pressing and closing mechanism (5) includes a pressing block (51), a horizontal pushing block (52), and an abutting block (53); a first vertical channel (22) is vertically opened in the transverse bearing beam (2) below the positioning groove (21), and the pressing block (51) is slidably inserted in the first vertical channel (22); a transverse channel (23) is horizontally opened in the transverse bearing beam (2), the transverse channel (23) is perpendicular to and connected to the first vertical channel (22), and the horizontal pushing block (52) is slidably inserted in the transverse channel (23); a second vertical channel (24) is vertically opened in the transverse bearing beam (2) near the end, and the second vertical channel (24) is also away from the first vertical channel from the transverse channel (23). (22) is vertically connected at one end, and the abutment block (53) is vertically slidably inserted into the second vertical channel (24); the pressing block (51) and the horizontal pushing block (52) and the abutment block (53) and the horizontal pushing block (52) are all in contact with each other through the inclined abutment surface (7). When the pressing block (51) moves vertically downward, the horizontal pushing block (52) is displaced in the transverse channel (23) and pushes the abutment block (53) to move vertically upward; a connecting beam (31) is horizontally arranged on the vertical hanging beam (3), and a connecting block (32) is arranged on the connecting beam (31) directly above the abutment block (53). After the abutment block (53) moves upward and is in contact with the connecting block (32), the end of the transverse bearing beam (2) is closed; A connecting beam (31) is horizontally arranged on the vertical hanging beam (3). A connecting block (32) is arranged on the connecting beam (31) directly above the abutting block (53). After the abutting block (53) moves up and fits against the connecting block (32), it closes the end of the transverse bearing beam (2). When the wire rope is removed from the positioning groove (21) or no pressure is applied to the positioning groove (21), the compression closing mechanism automatically opens the end of the transverse bearing beam (2); while the contact alarm mechanism (6) automatically alarms when the end of the transverse bearing beam (2) is opened and automatically cuts off power when the end of the transverse bearing beam (2) is closed.

2. The construction process of prefabricated and assembled box culverts according to claim 1, characterized in that, In the construction steps of the culvert prefabrication area, the prefabrication site is leveled by bulldozers, and then compacted by a 20T vibratory roller. A 20cm gravel cushion layer is laid in the culvert storage area, and the culvert prefabrication area is hardened with 10cm thick C20 concrete. A 12mm nominal diameter threaded steel bar is installed under the culvert prefabrication platform.

3. The construction process for prefabricated and assembled box culverts according to claim 1, characterized in that, In the construction steps of the culvert prefabrication operation area, drainage ditches are pre-installed when the prefabrication site is hardened.

4. The construction process of prefabricated and assembled box culverts according to claim 1, characterized in that, In the culvert concrete pouring process, the concrete is poured at the most favorable time of day. That is, during summer construction, the concrete pouring of the culvert is carried out in the morning or evening when the temperature is lower, avoiding the high temperature period of noon and afternoon. During winter construction, the concrete pouring is carried out during the warmer period of day, that is, in the morning or at noon, avoiding the evening and the period around sunrise.

5. The construction process of prefabricated and assembled box culverts according to claim 1, characterized in that, One side of the first vertical channel (22), the second vertical channel (24), and the transverse channel (23) is provided with an elastic cavity (8) along its own direction. The pressing block (51), the horizontal pushing block (52), and the abutting block (53) are all provided with protrusions (9) that extend into the elastic cavity (8). A spring (81) is provided between each protrusion (9) and the end wall of the elastic cavity (8). The spring (81) located on the side of the pressing block (51) always has the tendency to push the pressing block (51) vertically upward. The spring (81) located on the side of the horizontal pushing block (52) always has the tendency to push the horizontal pushing block (52) horizontally towards the pressing block (51). The spring (81) located on the side of the abutting block (53) always has the tendency to push the abutting block (53) vertically downward.

6. The construction process of prefabricated and assembled box culverts according to claim 1, characterized in that, The contact alarm mechanism (6) includes a power-on alarm mechanism (61) and a power supply mechanism (62); the power supply mechanism (62) is installed on the connecting beam (31), and the power-on alarm mechanism (61) is installed on the vertical hanging beam (3). The power supply mechanism (62) is used to supply electrical energy to the power-on alarm mechanism (61) when the abutting block (53) abuts against the docking block (32). The power-on alarm mechanism (61) is used to emit a warning sound after power is applied and to turn off the warning sound after power is cut off.

7. The construction process for prefabricated and assembled box culverts according to claim 6, characterized in that, The power supply mechanism (62) includes a mounting block (621), a battery (622), and a hinge rod (623); the mounting block (621) is located at the end of the connecting beam (31), and a storage cavity (6211) is provided inside the mounting block (621). The battery (622) is placed in the storage cavity (6211). A sliding cavity (6212) is provided on the mounting block (621) at the lower end of the storage cavity (6211). The connecting block (3) 2) Slidingly inserted into the sliding cavity (6212); a through-hole (6213) is vertically opened on the side wall of the sliding cavity (6212), and a stop rod (321) extending out of the through-hole (6213) is provided on the side wall of the docking block (32) near the top. The hinge rod (623) is hinged to the connecting beam (31), and the end of the stop rod (321) is connected to one end of the hinge rod (623) through a tension spring; the power-on alarm mechanism (61) The system includes an alarm (611) and a conductive block (612). The alarm (611) is mounted on a vertical suspension beam (3), and the conductive block (612) is mounted on the side of the vertical suspension beam (3) near the hinge rod (623), and the conductive block (612) is electrically connected to the alarm (611). A conductive sheet (6231) is provided at the end of the hinge rod (623) away from the tension spring, and the conductive sheet (6231) is electrically connected to the battery (622). When the contact block (53) abuts against the contact block (32) and moves vertically upward in the sliding cavity (6212), the end of the hinge rod (623) away from the tension spring tilts downward and causes the conductive sheet (6231) to separate from the conductive block (612); when the contact block (53) no longer abuts against the contact block (32) and causes the contact block (32) to move vertically downward in the sliding cavity, the hinge rod (623) is in a horizontal state and causes the conductive sheet (6231) to adhere to the conductive block (612).

8. The construction process of prefabricated and assembled box culverts according to claim 1, characterized in that, In the installation of the culvert joint, a two-component polysulfide sealant is used for the sealant, and a water-swellable waterstop is used for the waterstop strip.

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