A method of controlling the thickness of floor concrete

Abstract

The application provides a floor concrete thickness control method, and belongs to the technical field of concrete construction.The application uses airtight communication pipe network to fill colored liquid to form a physical horizontal reference covering the whole pouring area, arranges impact-resistant prefabricated concrete pie-shaped pads with a height precision of plus or minus 0.5 mm on the floor reinforcement mesh to stabilize the thickness control point elevation, sets up a laser ranging sensor matrix frame to continuously collect the real-time concrete thickness of each measuring point at a frequency of 10 Hz and generate a thickness distribution cloud picture, solves the Nash equilibrium by a double-layer game model to output the priority ranking of the out-of-tolerance measuring points and the optimal travel path of the operating personnel to guide the closed-loop correction, and after pouring is completed, polypropylene fibers are mixed and film curing is performed to inhibit early plastic shrinkage cracks, so that the technical problem that the thickness deviation cannot be controlled in real time in the floor concrete pouring process is solved.

Description

Technical Field

[0001] This invention belongs to the field of concrete construction technology, and more specifically, relates to a method for controlling the thickness of concrete slabs. Background Technology

[0002] Controlling the thickness of concrete slabs is a crucial step in building construction, directly impacting the load-bearing capacity and performance of the slab. Current technology primarily relies on manually inserting rebar ends or mortar spots as thickness markers, combined with localized spot checks using levels or laser levels. Construction workers judge whether the concrete surface elevation meets design requirements based on experience. This method is widely used in large-area pouring projects, especially in high-rise building slabs, basement roofs, and large-span transfer floors, where the combination of manual markers and discrete spot checks is the current mainstream approach. However, this method has several inherent drawbacks: excessively large marker spacing leads to insufficient coverage density; manual interpretation introduces visual errors; and the elastic deformation of the formwork under the concrete's own weight cannot be pre-compensated, resulting in a systematically thinner mid-span slab after pouring. Vibration operations cause localized concrete flow, causing continuous fluctuations in the concrete elevation near the thickness markers during pouring. Furthermore, the aforementioned discrete spot check methods cannot track the dynamic changes in thickness across the entire area, and deviations are often discovered after the correctable time window has passed. In other words, existing technologies have the technical problem that thickness deviations during the concrete pouring process of floor slabs cannot be controlled in a real-time closed-loop manner. Summary of the Invention

[0003] In view of this, the present invention provides a method for controlling the thickness of floor slab concrete, which can solve the technical problem in the prior art that the thickness deviation during the pouring of floor slab concrete cannot be controlled in real time in a closed loop.

[0004] This invention is implemented as follows: This invention provides a method for controlling the thickness of concrete slabs, comprising the following steps:

[0005] Based on the design thickness and calculated span of the floor slab, the predicted value of the elastic deflection at mid-span of the formwork system is calculated. The predicted value of the elastic deflection at mid-span is inverted and used as the preset arch of the formwork. By adjusting the height of the top support screw, a reverse arch corresponding to the preset arch of the formwork is formed at the mid-span position of the formwork. The ratio of the mid-span deflection of the formwork to the calculated span of the floor slab is controlled within 1 / 400.

[0006] A closed-loop pipe network is laid around the pouring area and in the middle of the span. A colored liquid is filled into the closed-loop pipe network. The liquid level at each pipe opening is set to the design top elevation of the floor slab. The self-balancing liquid level of the closed-loop pipe network is used to keep the liquid level at each pipe opening at the design top elevation of the floor slab, forming a horizontal reference plane for the entire area.

[0007] Impact-resistant precast concrete disc-shaped pads are laid on the floor slab reinforcement mesh at a spacing of no more than 1500mm. The height of the impact-resistant precast concrete disc-shaped pads is equal to the design thickness of the floor slab, and the height accuracy is controlled within ±0.5mm. The horizontal distance between the insertion point of the vibrator and the impact-resistant precast concrete disc-shaped pads is no less than 300mm.

[0008] A laser ranging sensor matrix frame is erected above the pouring area. The laser ranging sensor matrix frame is composed of multiple laser ranging sensors arranged and fixed in a grid with a spacing of 1500mm. Each laser ranging sensor collects the real-time distance from the laser ranging sensor to the concrete surface at a frequency of 10Hz. The controller calculates the real-time concrete thickness at each measuring point based on the difference between the real-time distance from the laser ranging sensor to the concrete surface and the fixed height from the laser ranging sensor to the bottom of the template, and generates a thickness distribution cloud map. The thickness distribution cloud map marks the real-time concrete thickness at each measuring point and the coordinates of the out-of-tolerance area.

[0009] The controller compares the real-time concrete thickness at each measuring point with the design thickness of the floor slab. When the absolute value of the difference between the real-time concrete thickness at any measuring point and the design thickness of the floor slab exceeds 5mm, the audible and visual alarm system will issue a prompt. The operators will then replenish the thinner measuring points and scrape off the thicker measuring points according to the coordinates of the out-of-tolerance area and the horizontal reference of the entire area, so that the absolute value of the difference between the real-time concrete thickness at each measuring point and the design thickness of the floor slab does not exceed 5mm.

[0010] Immediately after pouring, cover with a moisture-retaining curing film and keep the concrete surface moist for at least 14 days. Add the following to the concrete by volume: Polypropylene fibers are incorporated to suppress early plastic shrinkage cracks. Thickness acceptance measurement is carried out after the concrete has reached 28 days of age, and the measurement results after 28 days of age are used as the acceptance benchmark.

[0011] The predicted value of elastic deflection at mid-span refers to the maximum vertical displacement at mid-span of the formwork system obtained by calculating the maximum vertical displacement at mid-span of a simply supported slab under uniformly distributed load of concrete self-weight, based on the relationship between elasticity and calculation of the maximum vertical displacement at mid-span of a simply supported slab under uniformly distributed load. The predicted value of elastic deflection at mid-span is directly proportional to the fourth power of the calculated span of the floor slab and inversely proportional to the bending stiffness of the formwork section.

[0012] The pre-set arch of the template refers to a vertical offset that is set at the mid-span position during the template erection stage. This offset is equal in magnitude and opposite in direction to the predicted elastic deflection value at the mid-span. It is used to cancel out the predicted elastic deflection value at the mid-span when the template sinks after the concrete is poured, so that the top surface of the hardened floor slab approaches the design plane.

[0013] The closed-loop pipe network refers to the interconnected closed pipe system laid around and inside the pouring area. After the closed-loop pipe network is filled with colored liquid, according to the principle of communicating vessels, the liquid level at each pipe opening automatically maintains the same horizontal height in a static state, with an elevation consistency accuracy better than ±1mm.

[0014] The colored liquid refers to a coloring liquid prepared by adding non-corrosive water-soluble pigments to water, so that the liquid surface at each pipe opening has sufficient visual contrast in the pouring environment, making it easy for workers to directly observe the height relationship between the concrete surface and the horizontal reference plane of the entire area.

[0015] The impact-resistant precast concrete disc-shaped pad refers to a thickness control component precast into a disc shape using concrete with a strength grade of not less than C40. The height accuracy is ±0.5mm. It can withstand the lateral impact force of the vibrator without bending, ensuring that the elevation of each thickness control point remains stable throughout the entire pouring process.

[0016] The horizontal distance between the insertion point of the vibrator and the impact-resistant precast concrete disc pad should be no less than 300mm to avoid the local liquefaction flow zone generated during the operation of the vibrator affecting the elevation stability of the concrete around the impact-resistant precast concrete disc pad.

[0017] The fixed height of the laser rangefinder sensor to the bottom of the template refers to the constant vertical distance between the laser rangefinder sensor's emission point and the bottom of the template after installation, which is determined by on-site measurement before pouring. The real-time concrete thickness at each measuring point is equal to the fixed height of the laser rangefinder sensor to the bottom of the template minus the real-time distance between the laser rangefinder sensor and the concrete surface.

[0018] The thickness distribution cloud map refers to a two-dimensional visualization graphic that uses planar coordinates to represent the location of measuring points and numerical values ​​to represent the real-time concrete thickness at each measuring point. The coordinates of out-of-tolerance areas are automatically marked on the thickness distribution cloud map by the controller.

[0019] The layout of the sensors in the laser ranging sensor matrix framework is determined by establishing an optimization model with the objective function of minimizing the number of laser ranging sensors and the effective coverage radius and blind area of ​​a single laser ranging sensor as constraints. A 1500mm equally spaced grid is used to meet the coverage constraints.

[0020] The control process is optimized using a two-layer game model, which consists of an upper-layer model that aims at thickness uniformity and a lower-layer model that aims at work efficiency. The upper-layer model outputs the priority ranking of the adjustment amount required for each out-of-tolerance measurement point, and the lower-layer model outputs the optimal travel path for the workers.

[0021] The objective function of the upper-level model takes the sum of the squares of the differences between the real-time concrete thickness and the design thickness of the floor slab at all measuring points in the entire area divided by the total number of measuring points, and the ratio of the number of out-of-tolerance measuring points to the total number of measuring points as input. The constraint condition is that the absolute value of the difference between the real-time concrete thickness and the design thickness of the floor slab at any measuring point does not exceed 5mm.

[0022] The objective function of the lower-level model takes the ratio of the distance between adjacent out-of-tolerance measuring points to the moving speed of the operator as input, and the time required for the operator to complete a single replenishment or scraping operation as input. The constraint is that the operator can only process one out-of-tolerance measuring point at any time. The coupling term of the two objective functions is the number of out-of-tolerance measuring points that are processed and adjusted to the qualified state per unit time. The control scheme is obtained after solving the Nash equilibrium.

[0023] The polypropylene fiber refers to synthetic fiber made from polypropylene as a raw material, and is added in volume fractions. It is uniformly dispersed in the concrete matrix and restricts the initiation and propagation of early plastic shrinkage cracks through fiber bridging.

[0024] The thickness acceptance measurement is carried out after the concrete has reached 28 days of age. The measurement result after 28 days of age is used as the acceptance benchmark so that the acceptance thickness represents the final stable state of the floor slab and avoids the incomparability between measurement results at different ages due to shrinkage deformation.

[0025] This invention organically integrates template pre-camber compensation, a closed-loop horizontal benchmark for the entire sealed and connected pipe network, impact-resistant precast concrete disc-shaped pads, real-time monitoring by a laser ranging sensor matrix, and path optimization using a two-layer game model. This constructs a closed-loop thickness control system that runs throughout the entire pouring process, solving the technical problem of real-time closed-loop control of thickness deviation during floor slab concrete pouring. Before pouring, this invention predicts and compensates for template deflection using elastic mechanics, eliminating the root cause of systematic cross-sectional deviations. During pouring, it establishes a physical horizontal benchmark independent of electronic devices using the principle of communicating vessels, while a laser ranging sensor matrix continuously collects thickness data across the entire area at a frequency of 10Hz, allowing quantitative identification of thickness deviations at any given time. When the deviation exceeds the limit, the two-layer game model simultaneously outputs a priority ranking of out-of-tolerance measurement points and the optimal travel path for workers, guiding them to complete closed-loop correction before the concrete initially sets. In summary, this invention solves the technical problem mentioned in the background art of the inability to control thickness deviation in real-time closed-loop during floor slab concrete pouring. Attached Figure Description

[0026] Figure 1 This is a flowchart of the method of the present invention.

[0027] Figure 2 This is a schematic diagram showing the distribution of liquid level at each pipe opening in a closed, interconnected pipe network.

[0028] Figure 3 This is a schematic diagram illustrating the principle of forming a horizontal reference surface across the entire region.

[0029] Figure 4 This is a schematic diagram of the coordinated deployment of a laser ranging sensor matrix frame and a closed, interconnected pipeline network. Detailed Implementation

[0030] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below.

[0031] like Figure 1 The diagram shows a flowchart of a method for controlling the thickness of concrete slabs provided by this invention. This method includes the following steps:

[0032] S10. Based on the design thickness and calculated span of the floor slab, calculate the predicted value of the elastic deflection at mid-span of the formwork system. Invert the predicted value of the elastic deflection at mid-span and use it as the preset arch of the formwork. By adjusting the height of the top support screw, a reverse arch corresponding to the preset arch of the formwork is formed at the mid-span position of the formwork. The ratio of the mid-span deflection of the formwork to the calculated span of the floor slab is controlled within 1 / 400.

[0033] S20. A closed and interconnected pipe network is laid around the pouring area and in the middle of the span. A colored liquid is filled into the closed and interconnected pipe network. The liquid level at each pipe opening is set to the design top elevation of the floor slab. The self-balancing liquid level of the communicating vessels in the closed and interconnected pipe network is used to keep the liquid level at each pipe opening at the design top elevation of the floor slab, forming a horizontal reference plane for the entire area.

[0034] S30. Impact-resistant precast concrete disc-shaped pads are laid on the floor slab reinforcement mesh at a spacing of no more than 1500mm. The height of the impact-resistant precast concrete disc-shaped pads is equal to the design thickness of the floor slab, and the height accuracy is controlled within ±0.5mm. The horizontal distance between the insertion point of the vibrator and the impact-resistant precast concrete disc-shaped pads is no less than 300mm.

[0035] S40. A laser ranging sensor matrix frame is erected above the pouring area. The laser ranging sensor matrix frame is composed of multiple laser ranging sensors arranged in a grid with a spacing of 1500mm. Each laser ranging sensor collects the real-time distance from the laser ranging sensor to the concrete surface at a frequency of 10Hz. The controller calculates the real-time concrete thickness at each measuring point based on the difference between the real-time distance from the laser ranging sensor to the concrete surface and the fixed height from the laser ranging sensor to the bottom of the template, and generates a thickness distribution cloud map. The thickness distribution cloud map marks the real-time concrete thickness and the coordinates of the out-of-tolerance area at each measuring point.

[0036] S50: The controller compares the real-time concrete thickness at each measuring point with the design thickness of the floor slab. When the absolute value of the difference between the real-time concrete thickness at any measuring point and the design thickness of the floor slab exceeds 5mm, the audible and visual alarm system issues a prompt. The operator replenishes the thinner measuring points and scrapes off the thicker measuring points according to the coordinates of the out-of-tolerance area and the horizontal reference of the entire area, so that the absolute value of the difference between the real-time concrete thickness at each measuring point and the design thickness of the floor slab does not exceed 5mm.

[0037] S60. Immediately after pouring, cover with a moisturizing and curing film to keep the concrete surface moist for no less than 14 days. Add polypropylene fiber to the concrete at a volume ratio of 0.9 kg / m³ to inhibit early plastic shrinkage cracks. Thickness acceptance measurement shall be carried out after the concrete has reached 28 days of age, and the measurement results after 28 days of age shall be used as the acceptance benchmark.

[0038] In step S10, the predicted mid-span elastic deflection refers to the maximum vertical displacement of the formwork system at mid-span, calculated based on the relationship between elasticity and the maximum vertical displacement of a simply supported slab under a uniformly distributed load of concrete self-weight. This predicted mid-span elastic deflection is directly proportional to the fourth power of the calculated slab span and inversely proportional to the bending stiffness of the formwork section. For every 0.5m increase in the calculated slab span, the predicted mid-span elastic deflection increases exponentially. The pre-set camber of the formwork refers to a vertical offset, equal in magnitude but opposite in direction to the predicted mid-span elastic deflection, pre-set at mid-span during the formwork erection stage. This offset cancels out the predicted mid-span elastic deflection when the formwork settles after concrete pouring, ensuring the hardened top surface of the slab approaches the design plane and eliminating systematic section deviations.

[0039] In step S20, the closed-loop pipe network refers to an interconnected closed pipe system laid around and inside the pouring area. After the closed-loop pipe network is filled with colored liquid, based on the principle of communicating vessels, the liquid level at each pipe opening automatically maintains the same horizontal height in a static state. The height of the liquid level at each pipe opening is preset to the design top elevation of the floor slab, thus providing workers with a physical horizontal reference that does not rely on electronic equipment and is not affected by vibration, with an elevation consistency accuracy better than ±1mm. The colored liquid is a coloring liquid prepared by adding non-corrosive water-soluble pigment to water, used to provide sufficient visual contrast for the liquid level at each pipe opening in the pouring environment, making it easy for workers to directly observe the height relationship between the concrete surface and the horizontal reference plane of the entire area. The horizontal reference plane of the entire area refers to a unified horizontal reference plane covering the entire pouring area, formed by the liquid levels at each pipe opening of the closed-loop pipe network, and the height of the horizontal reference plane of the entire area is equal to the design top elevation of the floor slab.

[0040] In step S30, the impact-resistant precast concrete disc-shaped pad refers to a thickness control component precast into a disc shape using concrete with a strength grade of not less than C40. The height of the impact-resistant precast concrete disc-shaped pad is equal to the designed thickness of the floor slab, with a height accuracy of ±0.5mm. The impact-resistant precast concrete disc-shaped pad can withstand the lateral impact force of the vibrator without bending, thereby ensuring that the elevation of each thickness control point remains stable throughout the pouring process. The requirement that the horizontal distance between the vibrator insertion point and the impact-resistant precast concrete disc-shaped pad is not less than 300mm is to avoid the local liquefaction flow zone generated during the operation of the vibrator affecting the elevation stability of the concrete around the impact-resistant precast concrete disc-shaped pad and to prevent the formation of local depressions around the thickness control points.

[0041] In step S40, the laser ranging sensor matrix frame refers to a measuring device in which multiple laser ranging sensors are arranged in a grid with a spacing of 1500mm and fixed on a rigid frame above the pouring area. Each laser ranging sensor emits a laser beam directly downwards and receives the reflected signal to obtain the real-time distance from the laser ranging sensor to the concrete surface. The fixed height of the laser ranging sensor to the bottom of the template refers to the constant vertical distance between the emission point of the laser ranging sensor and the bottom of the template after installation, which is determined by on-site measurement before pouring. The real-time concrete thickness at each measuring point is equal to the fixed height of the laser ranging sensor to the bottom of the template minus the real-time distance from the laser ranging sensor to the concrete surface. The thickness distribution cloud map is a two-dimensional visualization graphic that represents the measuring point position with planar coordinates and the real-time concrete thickness at each measuring point with numerical values. It is used to visually present the thickness distribution status of the entire pouring area. The coordinates of the out-of-tolerance areas are automatically marked by the controller in the thickness distribution cloud map. The deployment of sensors in the laser ranging sensor matrix framework is a planar coverage problem, namely, to achieve effective monitoring of the thickness at any location in a given casting area using the minimum number of laser ranging sensors. By establishing an optimization model with the minimum number of laser ranging sensors as the objective function and the effective coverage radius and blind area of ​​a single laser ranging sensor as constraints, the spacing of the laser ranging sensors is determined. This method uses a 1500mm equally spaced grid to meet the coverage constraints.

[0042] In step S50, the "thin" measuring points refer to those where the real-time concrete thickness in the thickness distribution cloud map is less than the designed floor slab thickness and the absolute value of the difference exceeds 5mm; the "thick" measuring points refer to those where the real-time concrete thickness in the thickness distribution cloud map is greater than the designed floor slab thickness and the absolute value of the difference exceeds 5mm. The adjustment process in step S50 employs a two-layer game model optimized by an upper-layer model targeting thickness uniformity and a lower-layer model targeting operational efficiency. The objective function of the upper-layer model takes the sum of the squares of the differences between the real-time concrete thickness and the designed floor slab thickness at all measuring points in the entire region divided by the total number of measuring points, and the ratio of the number of out-of-tolerance measuring points to the total number of measuring points as input. The output is the priority ranking of the adjustment amounts required for each out-of-tolerance measuring point, with the constraint that the absolute value of the difference between the real-time concrete thickness and the designed floor slab thickness at any measuring point does not exceed 5mm. The objective function of the lower-layer model uses the distance between adjacent out-of-tolerance measuring points as input. The ratio of the worker's movement speed to the output is the input, along with the time required for the worker to complete a single replenishment or scraping operation. The output is the worker's optimal path, with the constraint that the worker can only process one out-of-tolerance measurement point at any given time. The coupling term of the two objective functions represents the number of out-of-tolerance measurement points processed and adjusted to a qualified state per unit time. The upper-level model optimizes by maximizing the coupling term, while the lower-level model optimizes by minimizing the path corresponding to the coupling term. The two models are mutually constrained by the coupling term. Solving for the Nash equilibrium yields a control scheme that balances thickness uniformity and operational efficiency. The Nash equilibrium refers to a stable state in the two-level game model where neither the upper-level nor the lower-level model can improve their respective objective function values ​​by unilaterally changing their decisions. In other words, the priority ranking output by the upper-level model and the optimal path output by the lower-level model are mutually compatible and no longer change.

[0043] The polypropylene fiber mentioned in step S60 refers to a synthetic fiber made from polypropylene, with a volume fraction of 0.9 kg / m³. The fiber is uniformly dispersed within the concrete matrix, limiting the initiation and propagation of early plastic shrinkage cracks through fiber bridging. Early plastic shrinkage cracks refer to cracks that form on the concrete surface before it has fully hardened. This occurs because the rate of water evaporation from the concrete surface exceeds the rate of bleeding, causing tensile stress due to internal constraints on the surface volume shrinkage. When this tensile stress exceeds the concrete's tensile strength at that point, cracks form on the concrete surface, leading to localized surface spalling and thickness loss. Thickness acceptance measurements are conducted after the concrete has reached 28 days of age because the chemical and drying shrinkage of concrete tends to stabilize after 28 days. Using the measurement results after 28 days as the acceptance benchmark ensures that the accepted thickness represents the final stable state of the floor slab, avoiding incomparability between measurement results from different ages due to shrinkage deformation.

[0044] The specific implementation of step S10 is as follows: First, obtain two input parameters, the design thickness of the floor slab and the calculated span of the floor slab, based on the construction drawings. The calculated span of the floor slab is the net distance between the center lines of the supports. According to the calculation relationship of the maximum vertical displacement of a simply supported slab at mid-span under uniformly distributed load in elastic mechanics, the product of the concrete unit weight and the design thickness of the floor slab is taken as the uniformly distributed load. Combined with the flexural stiffness of the formwork system, the predicted value of the elastic deflection at mid-span is calculated. This predicted value is directly proportional to the fourth power of the calculated span of the floor slab and inversely proportional to the flexural stiffness of the formwork section. Therefore, for every 0.5m increase in the calculated span of the floor slab, the predicted value of the elastic deflection at mid-span will increase exponentially and needs to be recalculated. The predicted value of the elastic deflection at mid-span is reversed and used as the preset camber of the formwork. By adjusting the height of the top support screw, the formwork forms a reverse arch at mid-span position corresponding to the preset camber of the formwork. This keeps the ratio of the formwork mid-span deflection to the calculated span of the floor slab within 1 / 400. As a result, when the formwork sinks under the weight of the concrete after pouring, the reverse preset amount and the elastic deflection cancel each other out, making the top surface of the hardened floor slab approach the design plane and eliminating systematic cross-sectional deviations.

[0045] The specific implementation of step S20 is as follows: Vertically upward-pointing connecting pipes are installed around the perimeter of the pouring area, along the edge of the formwork and at mid-span intervals not exceeding 3 meters. These pipes are interconnected via flexible conduits to form a closed, interconnected pipe network. After installation, the network is filled with a colored liquid. The colored liquid is prepared by adding a non-corrosive, water-soluble pigment to clean water. The pigment concentration is determined to ensure a clear visual contrast between the liquid surface at the pipe openings and the gray background of the concrete under the given illumination conditions during pouring. Based on the principle of communicating vessels, the liquid surface at each pipe opening automatically maintains the same horizontal level in a static state, with an elevation consistency accuracy better than ±1mm. The liquid surface height at each pipe opening is pre-calibrated to the designed top elevation of the floor slab using a precision level. Thus, all the liquid surfaces at the pipe openings collectively constitute a horizontal reference plane covering the entire pouring area. During the pouring process, workers can directly observe the relative height between the concrete surface and the liquid surface at any location to determine whether the concrete at that location has reached the designed top elevation of the floor slab, without relying on electronic equipment or being affected by vibration.

[0046] The specific implementation of step S30 is as follows: The impact-resistant precast concrete disc-shaped spacers are precast into circular disc shapes using concrete with a strength grade of not less than C40. The disc diameter is not less than 50mm, and the height is equal to the designed thickness of the floor slab. The height accuracy is controlled within ±0.5mm through mold making and precision grinding. After precasting, each disc is randomly inspected with a micrometer. After the floor slab reinforcement mesh is tied, the impact-resistant precast concrete disc-shaped spacers are evenly distributed on the reinforcement mesh at a grid spacing of not more than 1500mm. The bottom surface of the spacer rests on the formwork surface, and the top surface is the designed top elevation of the floor slab. Because the impact-resistant precast concrete disc-shaped spacers are made of high-strength concrete, the circular disc cross-section has high bending stiffness and can withstand the lateral impact force of the vibrator without bending, ensuring that the elevation of each thickness control point remains stable throughout the pouring process. The horizontal distance between the insertion point of the vibrator and the impact-resistant precast concrete disc-shaped pad must be no less than 300mm. This spacing requirement is determined based on the physical mechanism that the concrete within the radius of action of the vibrator is in a local liquefaction and flow state, so as to avoid the vibration disturbance zone from overlapping with the concrete around the pad and to prevent the formation of local depressions around the thickness control point.

[0047] The specific implementation of step S40 is as follows: A rigid frame is installed above the pouring area. The frame height ensures that the laser rangefinder sensor emission point is at an appropriate height above the concrete pouring surface. Multiple laser rangefinder sensors are fixed to the rigid frame at 1500mm intervals to form a laser rangefinder sensor matrix frame. Each laser rangefinder sensor emits a laser beam directly downwards, continuously collecting the real-time distance from the sensor to the concrete surface at a frequency of 10Hz. The data is transmitted to the controller via wired or wireless means. Before pouring, a fixed height between the emission point of each laser rangefinder sensor and the bottom surface of the formwork is determined by on-site measurement. The real-time concrete thickness at each measuring point is equal to the fixed height minus the real-time distance. The controller maps the real-time concrete thickness of all measuring points to a plane coordinate system, generating a thickness distribution cloud map in color or numerical form. The thickness distribution cloud map automatically marks the real-time concrete thickness value and coordinates of out-of-tolerance areas at each measuring point for real-time reading by operators.

[0048] The specific implementation of step S50 is as follows: the controller compares the real-time concrete thickness at each measuring point with the designed thickness of the floor slab point by point. When the absolute value of the difference at any measuring point exceeds 5mm, the audible and visual alarm system immediately issues a prompt and marks the coordinates of the out-of-tolerance measuring point on the thickness distribution cloud map. The control process is optimized using a two-layer game model. The upper-layer model takes the sum of the squares of the differences between the real-time concrete thickness at all measuring points and the designed thickness of the floor slab in the entire area divided by the total number of measuring points, and the ratio of the number of out-of-tolerance measuring points to the total number of measuring points as inputs, and outputs the priority ranking of the adjustment amount required for each out-of-tolerance measuring point. The constraint condition is that the absolute value of the difference at any measuring point does not exceed 5mm. The lower-layer model takes the ratio of the distance between adjacent out-of-tolerance measuring points to the moving speed of the workers, and the time required for a single material replenishment or scraping operation as inputs, and outputs the optimal movement path for the workers. The constraint is that the operator can only process one out-of-tolerance measurement point at any given time; the coupling term of the two models is the number of out-of-tolerance measurement points that are processed and adjusted to the qualified state per unit time. The upper model optimizes by maximizing the coupling term, while the lower model optimizes by minimizing the travel path corresponding to the coupling term. By iteratively solving the Nash equilibrium, a control scheme that balances thickness uniformity and work efficiency is obtained. The operator replenishes material to the thinner measurement points and scrapes off the thicker measurement points according to the scheme until the absolute value of the difference between all measurement points does not exceed 5mm.

[0049] The specific implementation of step S60 is as follows: immediately after pouring, cover the concrete with a moisturizing curing film. The curing film should cover the entire concrete pouring surface, keeping the concrete surface continuously moist for no less than 14 days. During the concrete mixing stage, the volumetric dosage... Polypropylene fibers are uniformly added to the concrete mixture. These fibers form a three-dimensional, randomly distributed network within the concrete matrix. Through fiber bridging, they provide cross-crack tension when early plastic shrinkage cracks initiate, limiting crack propagation and preventing localized spalling and thickness loss of the concrete surface due to early plastic shrinkage cracks. Thickness acceptance measurements must be taken after the concrete has reached 28 days of age, at which point the chemical shrinkage and drying shrinkage of the concrete have tended to stabilize. The measurement results at this age are used as the acceptance benchmark to ensure that the accepted thickness represents the final stable dimensional state of the floor slab and avoids incomparability of measurement results due to differences in shrinkage at different ages.

[0050] It should be noted that the key technical ideas and their synergistic effects of this invention are as follows. The first key technical idea is the combination of elastic mechanics prediction and pre-set camber of the formwork. By calculating the predicted value of the mid-span elastic deflection of the formwork under the self-weight of concrete based on elastic mechanics before pouring and applying an equal amount of reverse offset in advance, the actual deformation of the formwork after loading cancels out the pre-set reverse offset, fundamentally eliminating the systematic cross-sectional deviation caused by the elastic deflection of the formwork. This is a preventative control mechanism that cannot be achieved by traditional methods relying on post-measurement correction. The second key technical idea is a dual benchmark system of a physical horizontal benchmark for communicating vessels and real-time monitoring by a laser ranging sensor matrix. The self-balancing characteristics of the liquid surface in communicating vessels provide a physical benchmark that is independent of electronic equipment and unaffected by vibration. The laser ranging sensor matrix transforms discrete sampling into continuous monitoring across the entire area. The two complement each other, ensuring the accuracy of thickness data from both macroscopic judgment and precise quantification perspectives. The third key technical approach is the closed-loop control of a two-layer game model. By solving for Nash equilibrium, the thickness uniformity objective and the operational efficiency objective are unified into a single control scheme. This ensures that deviation correction is completed optimally within a limited time window before the initial setting of the concrete, solving the problem of inefficiency caused by the chaotic correction sequence in traditional schemes. The synergistic effect of these three technical approaches is reflected in the following: after the preset camber eliminates systematic deviations, the deviation range monitored by the laser ranging sensor matrix is ​​significantly reduced, and the number of out-of-tolerance measurement points that the two-layer game model needs to handle is reduced. This makes it easier to complete the closed-loop correction within the time window, and the three form a progressively reinforcing control chain in terms of time sequence.

[0051] It should be noted that this invention also solves the following technical problem: First, the problem of localized surface thickness loss caused by early-stage plastic shrinkage cracks in concrete. After pouring, when the surface moisture evaporation rate exceeds the bleeding rate, the surface volume shrinkage is constrained by internal forces, generating tensile stress. When this tensile stress exceeds the tensile strength of the concrete at that time, cracks form. Crack propagation leads to localized surface spalling, causing localized thickness loss. This invention addresses this issue by adding a specific amount of [material] to the concrete according to its volumetric [specific dosage]. By incorporating polypropylene fibers, the fiber bridging mechanism provides cross-crack tensile force during the crack initiation stage, inhibiting crack initiation and propagation. Simultaneously, a moisture-retaining curing film slows down the surface moisture evaporation rate. This reduces the imbalance between the driving force for early plastic shrinkage crack formation and the material's resistance from two directions, thus protecting the thickness integrity of the floor slab surface. Secondly, there is the problem of incomparability of thickness measurement results at different ages. Concrete undergoes continuous chemical and drying shrinkage during hardening. Measurement results at different ages reflect the geometric dimensions under different shrinkage states, lacking a unified benchmark, leading to a lack of objective basis for acceptance judgments. This invention stipulates that thickness acceptance measurements must be conducted after the concrete has reached 28 days of age, at which point shrinkage deformation tends to stabilize. Using the measurement results at this age as the sole acceptance benchmark ensures the comparability of results at different measurement times, making the acceptance conclusions certain and repeatable.

[0052] Specifically, the principle of this invention is as follows: The fundamental reason why this invention can solve the above-mentioned technical problems is that it sets independent elimination mechanisms for the three types of error sources affecting thickness accuracy during the pouring process—systematic deviation caused by template elastic deflection, reference error caused by elevation benchmark drift, and local dynamic deviation caused by vibration disturbance—in a time sequence, and connects the three into a closed loop through information feedback. Specifically, the template preset camber utilizes the linear superposition relationship between elastic mechanical deflection and load to make the template return to horizontal after bearing the self-weight of concrete, thus eliminating systematic cross-sectional deviation from a physical perspective; the self-balancing characteristic of the liquid surface in the communicating vessel ensures that the horizontal benchmark remains at the same height throughout the vibration environment, eliminating the interference of benchmark drift on thickness judgment; the laser ranging sensor matrix directly calculates the thickness of each measuring point by subtracting the real-time distance from the fixed height difference, transforming discrete sampling into continuous monitoring throughout the entire area, so that the deviation detection time is earlier than the initial setting time of the concrete; the two-layer game model finds the Pareto optimal control scheme between the thickness uniformity target and the work efficiency target through Nash equilibrium solution, ensuring that the correction operation is completed within a finite time window. The above mechanism logically covers four stages in sequence: deviation prevention, benchmark protection, deviation detection, and deviation correction, forming a complete causal chain. Therefore, the technical solution of this invention is logically sound in principle and has sufficient conditions to solve the core technical problem.

[0053] The following provides a specific embodiment 1 of the present invention, and the specific implementation of each step in this embodiment 1 is described in detail below.

[0054] The specific implementation of step S10 is as follows: based on the design thickness and calculated span of the floor slab, and according to the calculation relationship of the maximum vertical displacement at mid-span of a simply supported slab under uniformly distributed load in elastic mechanics, the predicted value of the elastic deflection at mid-span of the formwork system is obtained. The formula for calculating the uniformly distributed line load per unit width of the formwork system is expressed as follows:

[0055] ;

[0056] In the formula, The unit width of the uniform wiring load in the template system is 1000 ohms. ; This refers to the unit weight of concrete, in units of... The value is usually taken as ; The design thickness for the floor slab is in mm; The calculation unit width is in mm, with a default value of 1000 mm. The formula for calculating the predicted mid-span elastic deflection is as follows:

[0057] ;

[0058] In the formula, The value is the predicted elastic deflection at mid-span of the template system, in mm. Calculate the span of the floor slab, in mm; The elastic modulus of the template system is expressed in units of 1. Obtained through materials testing; The moment of inertia of the template system section is given by . It is calculated from the cross-sectional dimensions of the template, i.e. ,in This represents the template cross-sectional height, in mm. The obtained... Inverted and used as the template preset arch ,Right now:

[0059] ;

[0060] In the formula, A pre-set camber is provided for the formwork, in mm; the negative sign indicates the direction is opposite to the deflection direction. A corresponding reverse camber is formed at the mid-span of the formwork by adjusting the height of the top support bolts, and the ratio of the mid-span deflection of the formwork to the calculated span of the floor slab is controlled to meet the following conditions:

[0061] ;

[0062] All quantities in the above formula are in mm, and the ratios are dimensionless.

[0063] The specific implementation of step S20 involves laying a closed, interconnected pipe network around the perimeter and mid-span of the pouring area. After filling with colored liquid, based on the principle of communicating vessels, the liquid level at each pipe opening automatically maintains the same horizontal height in a static state. The liquid level at each pipe opening is pre-set to the design top elevation of the floor slab, forming a horizontal reference plane for the entire area. The elevation consistency accuracy is better than ±1mm, providing workers with a physical horizontal reference that does not rely on electronic equipment and is not affected by vibration. The colored liquid is prepared from non-corrosive water-soluble pigments and water to ensure sufficient visual contrast of the liquid level at the pipe openings in the pouring environment.

[0064] The specific implementation of step S30 is as follows: impact-resistant precast concrete disc-shaped spacers are arranged on the floor slab reinforcement mesh at a spacing of no more than 1500mm. The concrete strength grade used is no less than C40, and the height of the spacers is equal to the design thickness of the floor slab. The height accuracy is controlled within ±0.5mm, and the horizontal distance between the insertion point of the vibrator and the pad block is not less than 300mm, so as to avoid the local liquefaction flow zone generated when the vibrator is working affecting the elevation stability of the concrete around the pad block.

[0065] The specific implementation of step S40 is as follows: A laser ranging sensor matrix frame is erected above the pouring area. The sensors are arranged in a grid with a spacing of 1500mm, and the real-time distance from each measuring point to the concrete surface is collected at a frequency of 10Hz. The formula for calculating the real-time concrete thickness at each measuring point is expressed as follows:

[0066] ;

[0067] In the formula, For the first Line number Real-time concrete thickness at the measuring points, in mm; For the first Line number The fixed height from the laser rangefinder sensor emission point to the bottom surface of the template, in mm, is determined by on-site measurement before pouring. For the first Line number The real-time distance from the laser rangefinder to the concrete surface, in mm, is collected by the sensor in real time. The controller will... The data represents the location of the measuring points in planar coordinates and the thickness in numerical values, generating a thickness distribution cloud map and automatically marking the coordinates of out-of-tolerance areas.

[0068] The specific implementation of step S50 is that the controller transmits the real-time concrete thickness at each measuring point. With floor slab design thickness By comparison, when the absolute value of the deviation at any measuring point exceeds 5mm, the condition is satisfied. When the issue is detected, the audible and visual alarm system issues a warning. Workers then replenish material at the thinner measuring points and scrape away material at the thicker measuring points, based on the coordinates of the out-of-tolerance area and the overall horizontal reference. The control process is optimized using a two-layer game theory model. The objective function of the upper-layer model is expressed as follows:

[0069] ;

[0070] In the formula, The objective function value of the upper-level model is dimensionless. This represents the total number of measuring points; The number of measurement points exceeding the tolerance, i.e., satisfying The number of measuring points; in the first item Divide the square of the thickness deviation by the square of the floor slab design thickness to achieve dimensionless measurement. The second term... It is dimensionless; the constraint condition is satisfied for all measuring points. The upper-level model outputs a priority sorting vector of the required adjustment amounts for each out-of-tolerance measurement point. The formula is expressed as follows:

[0071] ;

[0072] ;

[0073] In the formula, For the first Normalization priority for out-of-tolerance measurement points, dimensionless. A higher value indicates a higher priority for adjusting that measuring point; For the first Real-time concrete thickness at each out-of-tolerance measuring point, in mm; For the first Real-time concrete thickness at each out-of-tolerance measuring point, in mm; both numerator and denominator are expressed as... Normalized, dimensionless overall. The objective function of the lower-level model is expressed as follows:

[0074] ;

[0075] In the formula, This represents the objective function value of the lower-level model, which is dimensionless. For the first in the travel path The and the first The distance between the out-of-tolerance measurement points is in meters. The speed at which workers move, in units of The empirical value is 0.8 to 1.2. ; This is a time normalization reference value, in seconds (s), with a default value of 1 second. The first item is passed. (Unit: m) Normalized to dimensionless; For the workers to complete the first The time required for a single replenishment or scraping operation at each out-of-tolerance measuring point, in seconds; This is a reference value for the time of a single operation, in seconds (s). The default value is 30 seconds. The second item is approved. Will Normalized to dimensionless; the constraint is that the operator only processes one out-of-tolerance measurement point at any given time. The lower-level model outputs the optimal travel path vector. The formula is expressed as follows:

[0076] ;

[0077] In the formula, For the first operator Next, proceed to the out-of-tolerance measurement point number to be processed. ,and Each pair is unique. This constitutes a complete traversal of all out-of-tolerance measurement points. The two-layer model is coupled through a term... Mutual constraints Defined as the number of out-of-tolerance measurement points processed and adjusted to a qualified state per unit time, the upper-level model uses... Maximizing is the optimization direction, and the lower-level model is in line with... The shortest corresponding path is the optimization direction. The control scheme is obtained by solving the Nash equilibrium. The Nash equilibrium state satisfies the priority ranking output by the upper-level model. The optimal travel path output by the lower-level model They are mutually compatible and no longer change.

[0078] The specific implementation of step S60 is as follows: immediately after pouring, cover with a moisturizing curing film, keep the concrete surface moist for no less than 14 days, and add 0.9% of the concrete by volume. Polypropylene fibers are incorporated to inhibit the initiation and propagation of early plastic shrinkage cracks through fiber bridging, preventing localized thickness loss caused by surface spalling. Thickness acceptance measurements are conducted after the concrete has reached 28 days of age, and the measurement results after this age are used as the acceptance benchmark to ensure that the accepted thickness represents the final stable state of the floor slab.

[0079] To better understand and implement this invention, the following is a specific application scenario of the invention, Example 2: To verify the effect of the invention, the technicians set up a test environment and conducted a full-process test on the pouring construction of a standard floor slab on a certain floor. The designed thickness of the floor slab was 120mm, the calculated span of the floor slab was 6000mm, the designed strength grade of the concrete was C30, and the plane size of the pouring area was 18000mm×12000mm.

[0080] In step S10, technicians calculate the predicted value of the elastic deflection at mid-span of the formwork system based on elasticity mechanics. The formwork system uses wooden I-beams with cup-shaped supports, and the flexural stiffness of the cross section is determined based on measured parameters. Under the uniformly distributed load of the concrete self-weight, the predicted value of the elastic deflection at mid-span is calculated to be 8.2 mm. Based on this, the height of the top support bolt is increased by 8.2 mm at the mid-span position to form a reverse arch. The ratio of the formwork mid-span deflection to the calculated span of the floor slab is controlled within 1 / 400 to meet the preset arch requirements.

[0081] In step S20, technicians laid 28 vertical pipes at 2500mm intervals around the perimeter and mid-span of the pouring area. These vertical pipes were connected in series via flexible conduits to form a closed, interconnected pipe network. A colored liquid containing a water-soluble red pigment was injected into the network. A precision level was used to calibrate the liquid level at each pipe opening to the designed top elevation of the floor slab. The elevation consistency was confirmed to be better than ±1mm through multiple re-measurements, thus establishing a horizontal reference surface for the entire area. The layout of the closed, interconnected pipe network and the distribution of the liquid level at each pipe opening are shown below. Figure 2 and Figure 3 As shown, the liquid level at each pipe opening is at the same horizontal height, covering the entire pouring area.

[0082] In step S30, technicians prefabricated a batch of impact-resistant precast concrete disc-shaped spacers using C40 concrete. The discs were 80mm in diameter, and their height accuracy was controlled within ±0.5mm using precision molds and micrometers. Approximately 110 spacers were placed on the reinforcing mesh in a 1400mm × 1400mm grid. The top surface of each spacer marked the designed top elevation of the floor slab. The horizontal distance between the vibrator insertion point and the spacer was maintained at at least 300mm. The placement parameters of the impact-resistant precast concrete disc-shaped spacers are shown in Table 1.

[0083] Table 1. Layout parameters of impact-resistant precast concrete disc blocks

[0084]

[0085] In step S40, technicians installed a rigid frame 1200mm above the pouring area and fixed 117 laser rangefinders in a 1500mm × 1500mm grid, forming a laser rangefinder matrix frame, as shown below. Figure 4 As shown, the fixed height from each sensor's emission point to the bottom surface of the template was measured and entered into the controller before pouring. During the pouring process, each sensor continuously collected real-time distance data at a frequency of 10Hz. The controller calculated the real-time concrete thickness at each measuring point and generated a thickness distribution cloud map. The thickness distribution cloud map was refreshed every 1 second, and the coordinates of areas exceeding the tolerance were automatically marked on the cloud map. Typical thickness detection results at a certain moment during the test are shown in Table 2.

[0086] Table 2. Real-time concrete thickness sampling record at various measuring points at typical times.

[0087]

[0088] In step S50, the controller detects that the absolute value of the difference between measuring point B-5 and measuring point D-2 exceeds 5mm, and the audible and visual alarm system issues a prompt. The two-layer game model starts optimization calculation. The upper-layer model calculates the priority ranking of the two out-of-tolerance measuring points. The deviation of measuring point D-2 is +6.2mm, which is greater than the deviation of measuring point B-5 is -5.7mm. Based on the principle of maximizing the sum of squares of the comprehensive adjustment, measuring point D-2 has a higher priority than measuring point B-5. The lower-layer model takes the current position of the operator as the starting point, calculates the total length of the travel path of processing D-2 first and then B-5, compares it with the path of processing B-5 first and then D-2, solves the Nash equilibrium, and outputs the optimal travel path. The operator scrapes the material at measuring point D-2 and replenishes the material at measuring point B-5 according to the path. After processing, the absolute value of the difference between the two measuring points is reduced to within 5mm, and the out-of-tolerance mark on the thickness distribution cloud map is eliminated.

[0089] In step S60, immediately after pouring, a moisturizing curing film is applied to completely cover the poured surface, and the film is used for continuous moisturizing curing for 14 days. The concrete is mixed according to... Polypropylene fibers were incorporated and mixed evenly before pouring. After 28 days of curing, the thickness of the floor slab was measured for acceptance. The thickness measurement results at each measuring point are shown in Table 3. The absolute value of the difference between all measuring points did not exceed 5 mm, which meets the acceptance requirements.

[0090] Table 3. Sampling Results of Floor Slab Thickness Acceptance Measurement at 28 Days of Age

[0091]

[0092] The technological advancements of this invention compared to traditional methods are reflected in the following aspects. Traditional methods rely on manual markers and discrete sampling, lacking a pre-compensation mechanism for the elastic deflection deformation of the formwork, leading to a systematic thinning of the mid-span floor slab. This invention, through a combination of elastic mechanics prediction and pre-set formwork camber, eliminates the root cause of systematic cross-sectional deviations at the physical level before pouring, ensuring that the top surface of the floor slab after pouring approaches the design plane. This preventative control is theoretically impossible to achieve with traditional post-construction correction methods. Traditional methods have limited measurement point density, resulting in delayed deviation detection, often only being discovered after the concrete has exceeded the correctable time window. This invention, through a laser ranging sensor matrix continuously monitoring the entire area at a frequency of 10Hz, shifts the deviation detection time forward to before the initial setting of the concrete, providing ample operational time for closed-loop correction. Traditional methods lack an optimized basis for the order of deviation correction, leading to random handling by operators based on experience, resulting in delayed correction of high-priority out-of-tolerance measurement points. This invention solves the Nash equilibrium through a two-layer game model, unifying the thickness uniformity target and the operation efficiency target as the optimal control scheme, making the closed-loop correction logically optimal and ensuring the maximization of correction efficiency per unit time in principle.

[0093] It should be noted that the variables involved in this invention are explained in detail in Table 4.

[0094] Table 4. Variable Explanation Table

[0095]

[0096] The above description is merely a specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any changes or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in the present invention should be included within the scope of protection of the present invention.

Claims

1. A method for controlling the thickness of concrete slabs, characterized in that, Includes the following steps: Based on the design thickness and calculated span of the floor slab, the predicted value of the elastic deflection at mid-span of the formwork system is calculated. The predicted value of the elastic deflection at mid-span is inverted and used as the preset arch of the formwork. By adjusting the height of the top support screw, a reverse arch corresponding to the preset arch of the formwork is formed at the mid-span position of the formwork. The ratio of the mid-span deflection of the formwork to the calculated span of the floor slab is controlled within 1 / 400. A closed-loop pipe network is laid around the pouring area and in the middle of the span. A colored liquid is filled into the closed-loop pipe network. The liquid level at each pipe opening is set to the design top elevation of the floor slab. The self-balancing liquid level of the closed-loop pipe network is used to keep the liquid level at each pipe opening at the design top elevation of the floor slab, forming a horizontal reference plane for the entire area. Impact-resistant precast concrete disc-shaped pads are laid on the floor slab reinforcement mesh at a spacing of no more than 1500mm. The height of the impact-resistant precast concrete disc-shaped pads is equal to the design thickness of the floor slab, and the height accuracy is controlled within ±0.5mm. The horizontal distance between the insertion point of the vibrator and the impact-resistant precast concrete disc-shaped pads is no less than 300mm. A laser ranging sensor matrix frame is erected above the pouring area. The laser ranging sensor matrix frame is composed of multiple laser ranging sensors arranged and fixed in a grid with a spacing of 1500mm. Each laser ranging sensor collects the real-time distance from the laser ranging sensor to the concrete surface at a frequency of 10Hz. The controller calculates the real-time concrete thickness at each measuring point based on the difference between the real-time distance from the laser ranging sensor to the concrete surface and the fixed height from the laser ranging sensor to the bottom of the template, and generates a thickness distribution cloud map. The thickness distribution cloud map marks the real-time concrete thickness at each measuring point and the coordinates of the out-of-tolerance area. The controller compares the real-time concrete thickness at each measuring point with the design thickness of the floor slab. When the absolute value of the difference between the real-time concrete thickness at any measuring point and the design thickness of the floor slab exceeds 5mm, the audible and visual alarm system will issue a prompt. The operators will then replenish the thinner measuring points and scrape off the thicker measuring points according to the coordinates of the out-of-tolerance area and the horizontal reference of the entire area, so that the absolute value of the difference between the real-time concrete thickness at each measuring point and the design thickness of the floor slab does not exceed 5mm. Immediately after pouring, cover with a moisture-retaining curing film and keep the concrete surface moist for at least 14 days. Add the following to the concrete by volume: Polypropylene fibers are incorporated to suppress early plastic shrinkage cracks. Thickness acceptance measurement is carried out after the concrete has reached 28 days of age, and the measurement results after 28 days of age are used as the acceptance benchmark.

2. The method for controlling the thickness of floor slab concrete according to claim 1, characterized in that, The predicted value of elastic deflection at mid-span refers to the maximum vertical displacement at mid-span of the formwork system obtained by calculating the maximum vertical displacement at mid-span of a simply supported slab under uniformly distributed load of concrete self-weight, based on the relationship between elasticity and calculation of the maximum vertical displacement at mid-span of a simply supported slab under uniformly distributed load. The predicted value of elastic deflection at mid-span is directly proportional to the fourth power of the calculated span of the floor slab and inversely proportional to the bending stiffness of the formwork section.

3. The method for controlling the thickness of floor slab concrete according to claim 2, characterized in that, The pre-set arch of the template refers to a vertical offset that is set at the mid-span position during the template erection stage. This offset is equal in magnitude and opposite in direction to the predicted elastic deflection value at the mid-span. It is used to cancel out the predicted elastic deflection value at the mid-span when the template sinks after the concrete is poured, so that the top surface of the hardened floor slab approaches the design plane.

4. The method for controlling the thickness of floor slab concrete according to claim 3, characterized in that, The so-called closed-loop pipe network refers to the interconnected closed pipe system laid around and inside the pouring area. After the closed-loop pipe network is filled with colored liquid, according to the principle of communicating vessels, the liquid level at each pipe opening automatically maintains the same horizontal height in a static state, with an elevation consistency accuracy better than ±1mm.

5. The method for controlling the thickness of floor slab concrete according to claim 4, characterized in that, The colored liquid refers to a coloring liquid prepared by adding non-corrosive water-soluble pigments to water, so that the liquid surface at each pipe opening has sufficient visual contrast in the pouring environment, making it easy for workers to directly observe the height relationship between the concrete surface and the horizontal reference plane of the entire area.

6. The method for controlling the thickness of floor slab concrete according to claim 5, characterized in that, The aforementioned impact-resistant precast concrete disc-shaped pad refers to a thickness control component precast into a disc shape using concrete with a strength grade of not less than C40. The height accuracy is ±0.5mm, and it can withstand the lateral impact force of the vibrator without bending, ensuring that the elevation of each thickness control point remains stable throughout the entire pouring process.

7. The method for controlling the thickness of floor slab concrete according to claim 6, characterized in that, The horizontal distance between the insertion point of the vibrator and the impact-resistant precast concrete disc pad should be no less than 300mm to avoid the local liquefaction flow zone generated during the operation of the vibrator affecting the elevation stability of the concrete around the impact-resistant precast concrete disc pad.

8. The method for controlling the thickness of floor slab concrete according to claim 7, characterized in that, The fixed height of the laser rangefinder sensor to the bottom of the template refers to the constant vertical distance between the laser rangefinder sensor's emission point and the bottom of the template after installation, which is determined by on-site measurement before pouring. The real-time concrete thickness at each measuring point is equal to the fixed height of the laser rangefinder sensor to the bottom of the template minus the real-time distance between the laser rangefinder sensor and the concrete surface.

9. The method for controlling the thickness of floor slab concrete according to claim 8, characterized in that, The thickness distribution cloud map refers to a two-dimensional visualization graphic that uses planar coordinates to represent the location of the measuring points and numerical values ​​to represent the real-time concrete thickness at each measuring point. The coordinates of the out-of-tolerance areas are automatically marked on the thickness distribution cloud map by the controller.

10. The method for controlling the thickness of floor slab concrete according to claim 9, characterized in that, The layout of sensors in the laser ranging sensor matrix framework is determined by establishing an optimization model with the objective function of minimizing the number of laser ranging sensors and the effective coverage radius and blind area of ​​a single laser ranging sensor as constraints. A grid with equal spacing of 1500mm is used to meet the coverage constraints.

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