Production process of prefabricated top plate of subway station

Abstract

The invention discloses a production process for a prefabricated top plate of a subway station. The production process for the prefabricated top plate of the subway station comprises the following steps that (1) a mold enters a site for acceptance and surface cleaning; (2) split type mold assembling: assembling a lower end mold and brushing a release agent, and then installing a steel reinforcement framework and assembling an upper end mold; (3) mounting an embedded part and verifying a tool; (4) concrete raw material inspection, dynamic mix proportion adjustment, pouring and vibrating; (5) carrying out galling treatment on the exposed surface and retaining a test block under the same condition; (6) temperature-controlled and humidity-controlled curing and finished product demolding are carried out; and (7) finished product quality inspection, identification and warehouse management. According to the production process for the prefabricated top plate of the subway station, through the arrangement of the split type mold rapid assembly technology and the temperature and humidity joint control maintenance technology, the production efficiency can be effectively improved, the maintenance cost is reduced, the maintenance time is shortened, the split type mold assembly technology is adopted, and the production efficiency is improved. The problems that a traditional integral mold is inconvenient to operate and high in slurry leakage rate are solved.

Description

Technical Field

[0001] This application relates to the technical field of municipal engineering, and in particular to a production process for precast roof slabs of subway stations. Background Art

[0002] With the acceleration of the urbanization process, subway stations, as an important part of urban infrastructure, have been expanding in construction scale year by year; precast concrete roof slabs have become the core components in the underground subway station project due to their advantages such as high standardization, fast construction speed, and controllable quality.

[0003] Currently, the fixed mold table production process is commonly used in the industry, which involves basic processes such as mold assembly, steel bar binding, concrete pouring, and curing.

[0004] Existing ordinary preparation molds are usually integral molds. The integral mold structure results in limited operating space, difficulty in inserting the steel bar skeleton into the mold, and the mold sealing depending on manual experience, with a relatively high leakage rate, which affects the appearance quality of the components.

[0005] At the same time, during the later curing, when steam curing is used, the energy consumption is large, and the temperature and humidity fluctuate greatly, which is prone to cause surface cracking of the components. While the natural curing period is long, which affects the construction efficiency.

[0006] That is, the existing technology has the following technical problems: the preparation efficiency of the ordinary precast slab production process is low, and leakage of slurry is likely to occur. Therefore, a production process for precast roof slabs of subway stations is proposed to address the above problems. Summary of the Invention

[0007] In this embodiment, a production process for precast roof slabs of subway stations is provided to solve the problems of low preparation efficiency and easy occurrence of slurry leakage in the existing ordinary precast slab production process.

[0008] According to one aspect of the present application, a production process for precast roof slabs of subway stations is provided. The production process for precast roof slabs of subway stations includes the following steps:

[0009] (1) Inspection and surface cleaning of the mold when it arrives at the site;

[0010] (2) Assembly of the split mold: First, assemble the lower mold and apply the release agent, and then install the steel bar skeleton and assemble the upper mold;

[0011] (3) Installation of embedded parts and verification of tooling;

[0012] (4) Inspection of concrete raw materials, dynamic mix ratio adjustment, pouring, and vibration;

[0013] (5) Texturing treatment of the exposed surface and retention of specimens under the same conditions;

[0014] (6)Temperature and humidity controlled curing and demolding of the finished product;

[0015] (7)Quality inspection, identification and warehousing management of the finished product.

[0016] Furthermore, the step (1) includes:

[0017] A. Detecting the dimensional deviation when the mold enters the site: length ±2mm, lateral bending ≤L / 1500 and ≤5mm;

[0018] B. Using an angle grinder with a wire wheel to clean the mold table and remove residues;

[0019] C. After cleaning, the flatness of the mold surface ≤2mm, without oil stains and rust.

[0020] Furthermore, the assembly of the split mold in the step (2) includes:

[0021] A. Assembly of the lower mold:

[0022] The pre-tightening force of the positioning bolt is 20 - 30N·m, and the perpendicularity error between the end mold and the bottom mold ≤1°;

[0023] After assembly, the flatness of the bottom mold ≤2mm, and the diagonal difference ≤3mm;

[0024] B. Assembly of the upper mold:

[0025] Sealant is filled at the joint of the side mold and the end mold, the curing time of the sealant ≤30min, and the gap ≤1mm;

[0026] Assembly verification standard: the height difference between the end mold and the side mold ≤0.5mm, and the warping degree ≤L / 2000.

[0027] Furthermore, the application of the release agent in the step (2) includes:

[0028] A. When applying the release agent, a water-based release agent is used, the spraying pressure is 0.3 - 0.5MPa, and the spraying distance is 200 - 300mm;

[0029] B. After the first application, a second application is carried out. The second application uses a dust-free mop, the coating thickness is 0.1 - 0.3mm, and the coverage rate ≥95%;

[0030] C. The installation of the embedded parts is completed within 30 minutes after the application to prevent contamination.

[0031] Furthermore, the installation of the embedded parts in the step (3) includes:

[0032] A. The embedded chute is fitted with the raised pin key on the bottom mold, the sponge strip at the joint is removed and sealant is filled;

[0033] B. Allowable deviation for the positioning of embedded parts: the center position is ±3 mm, and the horizontal elevation difference is ±2 mm;

[0034] C. The tooling verification is calibrated using a laser locator, and readjustment is required when the deviation exceeds 1 mm.

[0035] Furthermore, the concrete production in step (4) includes:

[0036] A. Raw material inspection: the mud content of sand and gravel is ≤3%, and the initial setting time of cement is ≥45 min;

[0037] B. Dynamic mix ratio: the water-binder ratio is adjusted in real time according to the aggregate moisture content, and corrected every 2 hours;

[0038] C. Pouring control:

[0039] The thickness of layered pouring is ≤300 mm, and it is vibrated and compacted using an inserted vibrator; the vibration spacing is 20 - 30 cm, the vibration time is controlled at 20 - 30 s for each point, and the insertion spacing of the vibrator is ≤400 mm;

[0040] D. The slump control value is 200 ± 20 mm, and the detection frequency for each truckload of material is ≥1 time per 2 m 3 .

[0041] Furthermore, the surface roughening treatment in step (5) includes:

[0042] A. Within 1 - 2 hours after the concrete begins to set, the exposed surface is treated using a mechanical surface roughening device;

[0043] B. The roughening depth is 3 - 5 mm, and the coverage rate of the rough surface is ≥80%;

[0044] C. The number of same - condition test blocks left is 3 groups for each pouring batch, and the curing conditions of the test blocks are exactly the same as those of the components.

[0045] Furthermore, in step (6):

[0046] A. The components are cured using a curing chamber;

[0047] B. The temperature change in the curing chamber is as follows:

[0048] a. Standstill for 2 h;

[0049] b. Heating up, with a heating rate ≤15℃ / h;

[0050] c. Constant temperature at 55℃ ± 5℃ for 4 h;

[0051] d. Cooling down, with a cooling rate ≤10℃ / h;

[0052] C. Humidity control: the humidity in the curing chamber is ≥90%, and automatic spray humidification is carried out every 1 hour;

[0053] D. Demoulding conditions: The compressive strength of the same-condition test block ≥ 75% of the design value, and the temperature difference between the core and the surface of the component ≤ 20°C.

[0054] Furthermore, the quality inspection in step (7) includes:

[0055] A. Appearance inspection: No exposed reinforcement, honeycombing, cracks, and the surface flatness ≤ 3 mm / 2 m;

[0056] B. Dimension inspection: The allowable deviation of length / width is ±5 mm, and the position deviation of embedded parts ≤ 3 mm;

[0057] C. Identification inspection: The waterproof QR code label is associated with the production date, strength grade, quality inspector, and batch number.

[0058] Furthermore, the warehousing management in step (7) includes:

[0059] A. The spacing of the cushion blocks for storing components ≤ 800 mm, and a 10-mm-thick rubber pad is laid between layers;

[0060] B. The stacking layer number ≤ 6 layers, and the height of the bottom-layer components from the ground ≥ 100 mm;

[0061] C. The storage area is partitioned and coded according to the assembly drawing, and the re-inspection pass rate before shipment is 100%.

[0062] Through the above technical solutions of the present application, a precast roof slab production process for a subway station provided by the present application can effectively improve the production efficiency, reduce the maintenance cost and maintenance time through the setting of the split mold rapid assembly technology and the temperature and humidity maintenance process, and is applicable to the alternating production requirements of multi-specification roof slabs in subway station projects. The process adopts the split mold assembly technology, which solves the problems of inconvenient operation and high slurry leakage rate of traditional integral molds, greatly shortens the mold preparation time and improves the assembly accuracy. The temperature and humidity maintenance process effectively optimizes the concrete forming quality, ensures the strength uniformity and apparent integrity of the components, and the mechanical surface roughening treatment of the exposed surface improves the bonding strength between the roof slab and the cast-in-place layer, avoiding the leakage risk caused by interface peeling after assembly. Brief Description of the Drawings

[0063] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the following will briefly introduce the drawings required for the description of the embodiments or the prior art. Obviously, the drawings in the following description are only some embodiments of the present application. For those of ordinary skill in the art, other drawings can be obtained based on these drawings without creative efforts.

[0064] Figure 1 It is the overall process schematic diagram of the present application;

[0065] Figure 2 It is a schematic flowchart of the first embodiment of the present application;

[0066] Figure 3 It is a schematic flowchart of the second embodiment of the present application. Detailed implementation manners

[0067] In order to enable those skilled in the art to better understand the solution of the present application, the technical solutions in the embodiments of the present application will be clearly and completely described below in conjunction with the accompanying drawings in the embodiments of the present application. Obviously, the described embodiments are only a part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present application.

[0068] It should be noted that the terms "first", "second", etc. in the specification, claims and the above drawings of the present application are used to distinguish similar objects, and do not necessarily need to be used to describe a specific order or sequence. It should be understood that such data can be interchanged under appropriate circumstances for the embodiments of the present application described herein. In addition, the terms "comprising" and "having" and any variations thereof are intended to cover non-exclusive inclusion. For example, a process, method, system, product or device that includes a series of steps or units does not necessarily have to be limited to those steps or units clearly listed, but may include other steps or units not clearly listed or inherent to these processes, methods, products or devices.

[0069] In the present application, the orientation or positional relationship indicated by the terms "upper", "lower", "left", "right", "front", "rear", "top", "bottom", "inner", "outer", "middle", "vertical", "horizontal", "lateral", "longitudinal", etc. is based on the orientation or positional relationship shown in the accompanying drawings. These terms are mainly used to better describe the present application and its embodiments, and are not used to limit that the indicated devices, elements or components must have a specific orientation or be constructed and operated in a specific orientation.

[0070] Moreover, in addition to being able to represent an orientation or positional relationship, some of the above terms may also be used to represent other meanings. For example, the term "upper" may also be used to represent a certain attachment relationship or connection relationship in some cases. For those of ordinary skill in the art, the specific meanings of these terms in the present application can be understood according to specific circumstances.

[0071] In addition, the terms "installed", "set up", "equipped with", "connected", "linked", and "socketed" should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral structure; it can be a mechanical connection or an electrical connection; it can be a direct connection, or an indirect connection through an intermediate medium, or an internal connection between two devices, components, or parts. For those of ordinary skill in the art, the specific meanings of the above terms in this application can be understood according to specific circumstances.

[0072] Please refer to Figures 1-3 As shown, a production process for precast roof slabs of a subway station, the production process for precast roof slabs of a subway station includes the following steps:

[0073] (1) Inspection and surface cleaning of the mold upon arrival;

[0074] (2) Assembly of the split mold: First, assemble the lower mold and apply the release agent, then install the steel reinforcement cage and assemble the upper mold;

[0075] (3) Installation of embedded parts and verification of tooling;

[0076] (4) Inspection of concrete raw materials, dynamic mix ratio adjustment, and pouring and vibration;

[0077] (5) Surface roughening treatment of the exposed surface and retention of specimens under the same conditions;

[0078] (6) Temperature and humidity controlled curing and demolding of the finished product;

[0079] (7) Quality inspection, identification, and warehousing management of the finished product.

[0080] Example 1:

[0081] Production of precast roof slabs of standard size

[0082] The production process for precast roof slabs of a subway station includes the following steps:

[0083] a. Mold treatment;

[0084] b. Assembly of the split mold;

[0085] c. Application of the release agent;

[0086] d. Verification of embedded parts and tooling;

[0087] e. Concrete pouring;

[0088] f. Surface treatment and curing;

[0089] g. Finished product management.

[0090] In step a, a split steel mold is used. The split steel mold includes a bottom mold, side molds, and end molds. When the molds enter the site, the length deviation of the molds is detected to be +1.5 mm, and the lateral bending is 0.8 mm. A wire wheel equipped with an angle grinder is used to clean the mold table; after cleaning, the flatness of the bottom mold is 1.2 mm, and the surface has no oil stain.

[0091] In step b, the split molds are assembled. First, the lower molds are installed. When installing, a pre-tightening force of 25 N·m is applied to the positioning bolts. The perpendicularity error between the end molds and the bottom mold is 0.5°. After assembly, the diagonal difference of the bottom mold is 2.3 mm, and the surface flatness is 1.5 mm.

[0092] In step c, a release agent is applied. An aqueous release agent is sprayed using a high-pressure spray gun; a dust-free mop is used for secondary brushing with a thickness of 0.2 mm and a coverage rate of 97%; the embedded parts are installed 25 minutes after brushing.

[0093] In step d, when installing the embedded parts, the deviation of the center position of the embedded chute is +2.5 mm, and the horizontal height difference is -1.8 mm; a laser locator is used to calibrate the tooling, and the positioning deviation after adjustment is 0.7 mm.

[0094] In step e, when pouring the concrete, the mud content of the sand and gravel is 2.8%, and the water-binder ratio is dynamically adjusted to 0.38; the layered pouring thickness is 280 mm, the insertion spacing of the vibrating rod is 350 mm, and the single-point vibration time is 25 seconds; the measured slump value is 205 mm, and each truckload of material is tested 3 times.

[0095] In step f, mechanical surface roughening is carried out 1.5 hours after the concrete begins to set, with a depth of 4.2 mm and a rough surface coverage rate of 85%. During the constant temperature stage of the curing chamber, the temperature is controlled at 53 °C, the humidity is 93%, and the temperature difference between the core and the surface is 18 °C.

[0096] In step g, the measured surface flatness value is 2.1 mm / 2 m, the deviation of the position of the embedded parts is +2.3 mm, the spacing of the cushion woods is 750 mm, 4 layers are stacked, the height from the bottom layer to the ground is 120 mm, and the associated information of the detection QR code label is checked.

[0097] Example 2:

[0098] Production of large-span precast roof slabs

[0099] The production process of the precast roof slab of a subway station includes the following steps:

[0100] a. Mold treatment and strengthening;

[0101] b. Assembly of split molds;

[0102] c. Tooling verification;

[0103] d. Concrete pouring;

[0104] e. Concrete curing;

[0105] f. Finished product management.

[0106] In the said step a, upon the acceptance of the mold upon its arrival at the site, reinforcing ribs are added to the bottom mold. The spacing of the reinforcing ribs is 500 mm. The detected length deviation is +1.8 mm, the lateral bending is 1.2 mm, the surface flatness after the mold table is cleaned is 1.5 mm, and there is no residual concrete slag.

[0107] In the said step b, the split mold is assembled. During the assembly, the pre-tightening force of the positioning bolts is 28 N·m, the perpendicularity error between the end mold and the bottom mold is 0.3°, the diagonal difference after the lower part of the mold is assembled is 2.8 mm, and the flatness of the bottom mold is 1.8 mm.

[0108] In the said step c, a laser locator is used for verification. After the laser locator is calibrated, the deviation is 0.6 mm. The parts exceeding the tolerance are corrected twice through adjusting bolts.

[0109] In the said step d, when preparing the concrete mixing ratio, 0.8% polycarboxylate water reducer is incorporated, the water-binder ratio is adjusted to 0.35; the slump control value is 215 mm, each truckload of material is detected 4 times, the thickness of the layered pouring is 250 mm, the insertion spacing of the vibrating rod is densified to 300 mm, and the single-point vibrating time is 22 seconds.

[0110] In the said step e, the static stopping stage is 3 hours to prevent the large-volume concrete from cracking. The heating rate is 12 °C / h, the total heating time is 3.5 h, the constant temperature is 58 °C ± 2 °C, the constant temperature time is 5 h, the cooling rate is 8 °C / h, and the total curing period is 20 hours;

[0111] The humidity inside the curing chamber is maintained at 95%, and automatic spray humidification is carried out every 45 minutes. When the formwork is removed, the core temperature of the component is 52 °C, the surface temperature is 50 °C, and the temperature difference ≤ 2 °C.

[0112] In the said step f, the detected surface flatness is 2.8 mm / 2 m, the deviation of the center position of the embedded pipe is +1.3 mm. During storage protection, the spacing of the cushion woods is reduced to 600 mm, a 15-mm rubber pad is laid between layers; the stacking limit is 3 layers, and the height from the ground of the bottom layer is 150 mm; anti-deformation support frames are added to prevent the self-weight deformation of large-span components.

[0113] The above are only the preferred embodiments of the present application and are not used to limit the present application. For those skilled in the art, various changes and modifications can be made to the present application. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present application shall be included within the protection scope of the present application.

Claims

1. A production process for a prefabricated roof of a subway station, characterized in that: The prefabricated roof production process of a subway station comprises the following steps: (1) Mold on-site inspection and surface cleaning; (2) Split mold assembly: first assemble the lower mold and apply the release agent, then install the steel frame and assemble the upper mold; (3) Embedded parts installation and tooling verification; (4) Inspection of concrete raw materials, dynamic mix ratio adjustment and pouring and vibration; (5) The exposed surface is roughened and the test pieces under the same conditions are retained; (6) Temperature and humidity control curing and demoulding of finished products; (7) Finished product quality inspection, labeling and warehouse management.

2. The process for producing a prefabricated roof slab for a subway station according to claim 1, characterized in that: The step (1) comprises: A. Dimensional deviation of the mold when it enters the site: length ±2mm, lateral bending ≤L / 1500 and ≤5mm; B. Use an angle grinder with a wire wheel to clean the die table and remove residue; C. After cleaning, the mold surface flatness is ≤2mm, free of oil stains and rust.

3. The process for producing a prefabricated roof slab for a subway station according to claim 1, characterized in that: The split mold assembly in step (2) includes: A. Lower end mold assembly: The pre-tightening force of the positioning bolt is 20-30N·m, and the verticality error between the end mold and the bottom mold is ≤1°; After assembly, the flatness of the bottom mold is ≤2mm, and the diagonal difference is ≤3mm; B. Upper mold assembly: The joint between the side mold and the end mold is filled with sealant, the curing time of the sealant is ≤30min, and the gap is ≤1mm; Assembly verification standard: height difference between end mold and side mold ≤0.5mm, warpage ≤L / 2000.

4. The process for producing a prefabricated roof slab for a subway station according to claim 1, characterized in that: The step (2) of applying the release agent comprises: A. The release agent is a water-based release agent, with a spraying pressure of 0.3-0.5MPa and a spraying distance of 200-300mm; B. Apply a second coat after brushing. Use a dust-free mop for the second coat. The coating thickness is 0.1-0.3mm and the coverage rate is ≥95%; C. Complete the installation of embedded parts within 30 minutes after painting to prevent contamination.

5. The process for producing a prefabricated roof slab for a subway station according to claim 1, characterized in that: The embedded parts installation in step (3) includes: A. The embedded slide groove is engaged with the raised pin key of the bottom mold, the sponge strip at the joint is removed and filled with sealant; B. Allowable deviation of embedded parts positioning: center position ±3mm, horizontal height difference ±2mm; C. The tooling verification is calibrated by a laser locator and readjusted when the deviation exceeds 1mm.

6. The process for producing a prefabricated roof slab of a subway station according to claim 1, characterized in that: The concrete production in step (4) comprises: A. Raw material inspection: sand and gravel mud content ≤3%, cement initial setting time ≥45min; B. Dynamic mix ratio: adjust the water-binder ratio according to the moisture content of aggregate and revise it every 2 hours; C. Pouring control: Layered pouring thickness ≤300mm, use inserted vibrator to vibrate and compact; the vibration interval is 20-30cm, the vibration time is controlled at 20-30s at each point, and the insertion interval of the vibrator is ≤400mm; D. Slump control value 200±20mm, testing frequency for each truckload ≥1 time / 2m 3 .

7. The process for producing a prefabricated roof slab for a subway station according to claim 1, characterized in that: The roughening treatment in step (5) comprises: A. Use a mechanical roughening device to treat the exposed surface within 1-2 hours after the initial setting of the concrete; B. The roughening depth is 3-5mm, and the rough surface coverage is ≥80%; C. The number of test blocks retained under the same conditions is 3 groups per casting batch, and the curing conditions of the test blocks are exactly the same as those of the components.

8. The process for producing a prefabricated roof slab of a subway station according to claim 1, characterized in that: In the step (6): A. Component maintenance is carried out in a maintenance cabin; B. The temperature change in the curing chamber is: a.Stand still for 2 hours; b. Heating, heating rate ≤ 15℃ / h; c. Constant temperature 55℃±5℃, constant temperature time 4h; d. Cool down, the cooling rate is ≤10℃ / h; C. Humidity control: The humidity in the curing chamber should be ≥90%, and the humidity should be automatically replenished by spraying every hour; D. Demoulding conditions: The compressive strength of the test block under the same conditions shall be ≥ 75% of the design value, and the temperature difference between the core and the surface of the component shall be ≤ 20°C.

9. The process for producing a prefabricated roof slab of a subway station according to claim 1, characterized in that: The quality inspection in step (7) includes: A. Appearance inspection: no exposed reinforcement, honeycomb, cracks, surface flatness ≤3mm / 2m; B. Dimension inspection: length / width allowable deviation ±5mm, embedded parts position deviation ≤3mm; C. Label inspection: The waterproof QR code label is associated with the production date, strength level, quality inspector and batch number.

10. The process for producing a prefabricated roof slab of a subway station according to claim 1, characterized in that: The warehouse management in step (7) includes: A. The spacing between component storage pads is ≤800mm, and 10mm thick rubber pads are laid between layers; B. The number of stacked layers is ≤ 6, and the height of the bottom layer components from the ground is ≥ 100mm; C. The warehouse area is divided and coded according to the assembly diagram, and the re-inspection pass rate before shipment is 100%.

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