Deformation control method for pouring construction of prefabricated drainage box culvert steel formwork

Abstract

The invention discloses a deformation control method for pouring construction of a prefabricated drainage box culvert steel formwork, and is suitable for the technical field of deformation control of box culvert formwork construction. The deformation control method comprises the steps of establishing an initial state, laying monitoring point positions, setting initial parameters, constructing a three-dimensional control model, performing real-time monitoring and data acquisition, and adjusting and controlling the pouring process, and can monitor and intelligently regulate and control the stress conditions of the inner mold side plate and the angle mold in real time; the stability of the pouring process and the concrete forming quality are ensured, and by constructing a three-dimensional control model and combining layered correction coefficients, PID algorithm inner ring control and displacement compensation outer ring control, dynamic regulation and control of target supporting force are achieved, and deformation is accurately restrained.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of deformation control of box culvert template construction in sea area water intake and drainage engineering, and particularly relates to a deformation control method for pouring construction of a prefabricated drainage box culvert steel template. BACKGROUND

[0002] In the sea area water intake and drainage engineering of a nuclear power plant, the box culvert, as a key hydraulic structure, undertakes the core functions of conveying cooling water and balancing the sea level. In the construction process of the prefabricated drainage box culvert, the deformation control of the steel template is crucial. If the deformation is too large, it may lead to substandard concrete pouring quality, even to phenomena such as explosive pouring, affecting the structural performance and service life of the box culvert. The traditional deformation control method often cannot accurately cope with the pressure changes borne by the inner template side plate and the corner template during the pouring process, and therefore, an effective and intelligent deformation control method is urgently needed. SUMMARY

[0003] The purpose of the application is to provide a deformation control method for the pouring construction of a prefabricated drainage box culvert steel template, which can monitor and intelligently control the stress conditions of the inner template side plate and the corner template in real time, ensuring the stability of the pouring process and the quality of the concrete molding.

[0004] To achieve the above-mentioned purpose, the application provides the following technical solutions:

[0005] A deformation control method for pouring construction of a prefabricated drainage box culvert steel template, comprising the following steps:

[0006] S1, establishing an initial state: assembling and debugging the inner template, outer template and end template of the prefabricated drainage box culvert steel template, the inner template comprising an inner template unit and a support adjustment unit, the inner template unit comprising a top plate, a side plate and a corner template, the top plate being arranged on the top surface of the main beam cross section, one end of each side plate being symmetrically hinged to the top plate on both sides, the other end of each side plate being symmetrically hinged to a corner template, the support adjustment unit comprising a horizontal adjustment oil cylinder and an inclined adjustment oil cylinder, the horizontal adjustment oil cylinder being arranged between the two side plates, each corner template being connected to the bottom of the main beam through an inclined adjustment oil cylinder, the horizontal adjustment oil cylinder and the inclined adjustment oil cylinder being controlled by a hydraulic system to form an initial state;

[0007] S2, laying out monitoring points:

[0008] First pressure sensors are arranged at the hinged points of the two ends of the horizontal adjustment oil cylinder and the side template to determine the side plate monitoring points; second pressure sensors are arranged at the hinged points of the end of the inclined adjustment oil cylinder and the corner template to determine the corner template monitoring points;

[0009] S3, initial parameter setting:

[0010] The inner mold, the outer mold and the end mold are assembled to form a to-be-poured cavity, and the design height of the to-be-poured cavity is set as H; the initial support force of the transverse adjusting oil cylinder to the side mold on one side before pouring is set as f 1,0 , and the initial support force of the oblique adjusting oil cylinder to the corner mold before pouring is set as f 2,0 ; the length of the side plate is set as L, and the length of the corner mold is set as l

[0011] S4, a three-dimensional control model is constructed, and a target support force f i (h,t) n (i=1, 2) is dynamically generated, that is, the relationship between the pouring height, time and the target support force during the pouring process:

[0012]

[0013] Wherein, f1(h,t) n represents the target support force of the transverse adjusting oil cylinder, which is used to balance the side pressure of the concrete on the side plate; f2(h,t) n represents the target support force of the oblique adjusting oil cylinder, which is used to resist the side pressure of the concrete expanding outward of the corner mold;

[0014] n represents the number of the support adjusting units arranged axially on the main beam;

[0015] k1 and k2 respectively represent the side plate bending moment balance coefficient and the corner mold force decomposition coefficient;

[0016] α(t) is a side plate correction coefficient, β(t) is a corner mold correction coefficient, and h is a real-time pouring height;

[0017] S5, real-time monitoring and data acquisition: the oil pressure of the transverse adjusting oil cylinder and the oblique adjusting oil cylinder during the pouring process is monitored in real time, the values of the first pressure sensor and the second pressure sensor are collected, the measured oil pressure is obtained, and the measured support force is obtained by conversion; the target support force f i (h,t) n is dynamically calculated, and the measured support force is compared with the target support force to judge whether the support meets the requirements under the current pouring state;

[0018] S6, adjustment and control of the pouring process: according to the degree that the measured support force exceeds the target support force f i (h,t) n , the oil pressure of the oil cylinder is regulated and controlled by combining the PID algorithm until the measured support force f i,实 meets the support requirements.

[0019] As a preferred technical scheme of the present application, the PID algorithm regulates and controls the oil pressure of the oil cylinder in step S6, and the specific steps are as follows:

[0020] S61, the error value of the measured support force and the target support force is calculated:

[0021] ei (t) n =f i (h,t) n -f i,实

[0022] Set the error value e i (t) n The threshold for exceeding the limit is e max If the actual supporting force exceeds the design threshold, it will cause the template to deform or the assembly to fail. The error threshold is determined as follows:

[0023] When e i (t) n <0, the supporting force of the lateral or oblique adjusting cylinder meets the standard, and no PID adjustment is required;

[0024] When 0<e i (t) n ≤e max Perform PID control;

[0025] When e i (t) n >e max If this occurs, the machine must be stopped immediately and the assembly of the side panels and corner molds must be checked.

[0026] S62, PID control:

[0027] Initialize PID parameters: PID parameters include the proportional constant K p Integral constant K i Differential constant K d ;

[0028] Calculate the adjustment amount based on the PID control algorithm:

[0029]

[0030] In the formula, Δf i (t) n K is the PID control variable. p K is a proportionality constant. i K is the integration constant. d It is a differential constant;

[0031] S63. Adjust the oil pressure of the hydraulic cylinder: according to the PID control value Δf i (t) n Adjust the oil pressure of the lateral adjusting cylinder and the oblique adjusting cylinder;

[0032] S65. Real-time monitoring and feedback: Real-time monitoring of the oil pressure in the cylinder mentioned in step S2 is performed and fed back to the PID controller for closed-loop control. Based on the actual control effect, the parameter K of the PID control algorithm is gradually adjusted.p , K i and K d , to achieve the best control effect.

[0033] Furthermore, before pouring after the precast drainage culvert steel formwork is assembled, the hydraulic system applies the designed pre-tightening force to the stable state to form the initial state, and the numerical values of the first pressure sensor and the second pressure sensor at this time are recorded, that is, the initial oil pressure P of the horizontal adjustment cylinder before pouring 1,0 and the initial oil pressure P of the diagonal adjustment cylinder before pouring 2,0 are calculated, and f 1,0 and f 2,0 satisfy the following relationship:

[0034] f 1,0 = P 1,0 ·A1·η

[0035] f 2,0 = P 2,0 ·A2·COSθ·η

[0036] where, η: mechanical efficiency of the hydraulic system, with a value range of 0.9 - 0.95, dimensionless, A1: effective area of the piston of the horizontal adjustment cylinder, m 2 ; A2: effective area of the piston of the diagonal adjustment cylinder, m 2 ; θ is the installation angle of the diagonal adjustment cylinder.

[0037] As a preferred technical solution of the present invention, the side plate correction coefficient α(t) and the corner mold correction coefficient β(t) are determined by a hierarchical control method, and are divided into three pouring stages according to the pouring height h:

[0038] Pouring stage I: h ≤ 0.2H, focusing on the adjustment of the corner mold, taking α(t) = 0.8, β(t) = 0.6;

[0039] Pouring stage II: 0.2H < h ≤ 0.5H, synchronously adjusting the side plate and the corner mold, taking α(t) = 1.0, β(t) = 0.9;

[0040] Pouring stage III: h > 0.5H, focusing on the adjustment of the side plate, taking α(t) = 1.2, β(t) = 1.1.

[0041] As a preferred technical solution of the present invention, the layout of the displacement monitoring unit is also included in step S2, including a laser rangefinder and an inclination sensor. The laser rangefinder is arranged at a position对准ing the midpoint of the side plate to monitor the midpoint deflection δ of the side plate, and the inclination sensor is arranged outside the hinge point of the corner mold and the side plate to monitor the angular change Δθ of the opening and closing of the corner mold;

[0042] When the angle of opening and closing of the corner modulus changes by Δθ > 1°, it triggers the adjustment of the differential coefficient, increasing it by (20%–30%)·K. d .

[0043] Furthermore, the preset warning threshold for midpoint deflection is L / 800. When the midpoint deflection δ of the side plate ≥ L / 800, additional force compensation is triggered. Where γ is a proportionality coefficient, which is dimensionless; f1 is the current supporting force, which is the target supporting force f1(h,t). n The current value; L is the length of the side plate.

[0044] As a preferred embodiment of the present invention, the precast drainage box culvert steel formwork includes end molds, outer molds, inner mold assemblies, and a platform. The box culvert foundation formed by steel reinforcement binding is placed on the platform. The inner mold assembly is placed in the inner cavity of the box culvert foundation. The outer mold is placed on both sides of the box culvert foundation. The end molds are placed at both ends of the box culvert foundation along the axial direction. An inner mold support is placed on each side of the platform. The inner mold assembly includes an inner mold, a walking system, and a hydraulic system. The walking system includes a main beam and a walking device. The main beam is placed directly above the platform, and both ends of the main beam are supported on the inner mold supports. The walking device is placed at both ends of the bottom of the main beam and between the two inner mold supports. A corresponding number of inner mold units are installed along the axial direction of the main beam according to a preset number to form the inner mold body. The inner mold also includes a mold-collecting device. Support adjustment units and mold-collecting devices are evenly spaced along the axial direction of the inner mold body. Each mold-collecting device is controlled by the hydraulic system to adjust the side plate and corner mold into position.

[0045] As a preferred embodiment of the present invention, the inner mold further includes a temporary support unit. The support adjustment unit, the temporary support unit and the mold closing device are arranged axially and evenly in sequence within the inner mold body. The temporary support unit includes a transverse strut and a diagonal strut. The diagonal strut is located between the bottom of the corner mold and the main beam. A pair of symmetrical side plates are supported by the transverse strut.

[0046] Furthermore, the side plate has an inclined section and a vertical section, and the two sides of the side plate are symmetrically connected to one end of the inclined section of the side plate. One end of the vertical section of each side plate is symmetrically hinged to the corner mold. The mold-retracting device includes a first mold-retracting cylinder and a second mold-retracting cylinder. The inclined section is opposite to the corner mold and the first mold-retracting cylinder is provided between the two. The vertical section is connected to the side of the main beam through the second mold-retracting cylinder.

[0047] In summary, compared with the prior art, the beneficial effects of the present invention are:

[0048] This invention achieves dynamic regulation of the target support force and precisely suppresses deformation by constructing a three-dimensional control model and combining hierarchical correction coefficients, PID algorithm inner-loop control, and displacement compensation outer-loop control.

[0049] First, the established three-dimensional control model can comprehensively and accurately simulate the stress and deformation trend of the precast drainage box culvert steel formwork during the pouring process. The model comprehensively considers the nonlinear distribution characteristics of the concrete lateral pressure and the structural mechanical characteristics of the formwork system, and organically combines key factors such as pouring height, time and target support force, providing a solid theoretical basis and accurate quantitative basis for the dynamic control of target support force.

[0050] Secondly, a layered correction coefficient is introduced to differentiate adjustments based on the stress characteristics of the side panels and corner molds at each stage. In the low-height stage, the focus is on corner mold adjustment. By setting smaller correction coefficients for the side panels and corner molds, the outward expansion of the formwork caused by concrete flow is effectively suppressed, resisting the impact of concrete flow. In the high-height stage, the side panel support is strengthened by further increasing the side panel correction coefficient, reinforcing the support of the side panels and resisting cumulative bending moments. This layered control strategy can dynamically adjust the correction coefficients of the lateral and oblique adjustment cylinders, accurately matching the distribution of concrete lateral pressure at different pouring stages, optimizing the distribution of support forces, thereby achieving refined control of formwork deformation, significantly reducing the risk of grout leakage, effectively controlling formwork deformation, and ensuring the forming quality and dimensional accuracy of the precast drainage box culvert.

[0051] Finally, the synergistic control of inner and outer loops, along with the introduction of the PID algorithm, enables the deformation control of the formwork system to exhibit rapid response, real-time adjustment, and high precision. This effectively addresses the dynamic changes in concrete lateral pressure during pouring, ensuring the formwork is in an ideal stress state at all times, thus improving the stability and reliability of the construction process. Based on the PID inner loop control, a displacement compensation outer loop control is added, further enhancing the accuracy and reliability of formwork deformation control. When the opening and closing angle of the corner formwork changes abnormally by more than 1°, the differential coefficients in the PID algorithm are adjusted promptly to enhance the predictive ability of angle change trends, suppress outward expansion trends in advance, and quickly eliminate angle deviations to prevent cumulative errors and improve the symmetry of the structures on both sides of the corner formwork. A pre-set warning threshold for midpoint deflection is also implemented. When the midpoint deflection of the side plate exceeds the warning value, an additional force compensation mechanism is triggered, dynamically increasing the additional force according to the degree of deflection exceeding the standard to enhance the support force of the side plate and effectively prevent further deformation. The displacement compensation outer loop control and the PID inner loop control work together to form a closed loop control, which provides dual protection for the formwork system. This further enhances the accuracy and stability of the formwork deformation control, ensures the stability and safety of the precast drainage culvert steel formwork during the pouring process, and improves the quality of the components and construction efficiency. Attached Figure Description

[0052] Figure 1 This is a flowchart of the deformation control method for the casting construction of prefabricated drainage box culvert steel formwork according to the present invention;

[0053] Figure 2This is a schematic diagram of the prefabricated drainage culvert steel formwork of the present invention;

[0054] Figure 3 for Figure 2 CC cross-section diagram;

[0055] Figure 4 for Figure 2 DD cross-section diagram;

[0056] Figure 5 This is a front view of the inner mold assembly of the present invention;

[0057] Figure 6 for Figure 5 AA cross-section diagram;

[0058] Figure 7 for Figure 5 BB cross-section diagram;

[0059] Figure 8 This is a schematic diagram showing the distribution of the support adjustment unit and the mold-forming device in the inner mold of the present invention;

[0060] In the diagram: 1-End mold, 2-Inner mold support, 3-Platform, 4-Inner mold assembly, 40-Inner mold, 400-Inner template unit, 4001-Top plate, 4002-Side plate, 40021-Sloping section, 40022-Vertical section, 4003-Corner mold, 401-Support adjustment unit, 4011-Horizontal adjustment cylinder, 4012-Sloping adjustment cylinder, 402-Mold retraction device, 4021-First mold retraction cylinder, 4022-Second mold retraction cylinder, 41-Walking system, 411-Main beam, 412-Walking device, 5-Outer mold. Detailed Implementation

[0061] The specific embodiments of the present invention will be further described below with reference to the accompanying drawings. It should be noted that these descriptions are for the purpose of aiding understanding the present invention, but do not constitute a limitation thereof. Furthermore, the technical features involved in the various embodiments of the present invention described below can be combined with each other as long as they do not conflict with each other.

[0062] Combined with appendix Figures 1-8 A method for controlling deformation during the casting of precast drainage box culvert steel formwork includes the following steps:

[0063] S1. Establishing the initial state: Assemble and debug the inner mold assembly 4, outer mold 5, and end mold 1 of the precast drainage culvert steel formwork. The inner mold assembly 4 includes an inner mold 40, which includes an inner template unit 400 and a support adjustment unit 401. The inner template unit 400 includes a top plate 4001, side plates 4002, and corner molds 4003. The top plate 4001 is located on the top surface of the cross section of the main beam 411, and a side plate 4002 is symmetrically hinged to each side of the top plate 4001. At one end, a corner mold 4003 is symmetrically hinged to the other end of each side plate 4002. The support adjustment unit 401 includes a lateral adjustment cylinder 4011 and an oblique adjustment cylinder 4012. The lateral adjustment cylinder 4011 is located between the two side plates 4002. Each corner mold 4003 is connected to the bottom of the main beam 411 through the oblique adjustment cylinder 4012. The lateral adjustment cylinder 4011 and the oblique adjustment cylinder 4012 are controlled by a hydraulic system to form an initial state.

[0064] S2. Setting up monitoring points:

[0065] First pressure sensors are installed at both ends of the lateral adjustment cylinder 4011 and the hinge points of the side mold to determine the monitoring point of the side plate 4002; second pressure sensors are installed at both ends of the oblique adjustment cylinder 4012 and the hinge points of the corner mold 4003 to determine the monitoring point of the corner mold 4003.

[0066] S3. Initial parameter settings:

[0067] The inner mold assembly 4, outer mold 5, and end mold 1 are assembled to form the cavity to be poured, and the design height of the cavity to be poured is set to H; the initial support force of the lateral adjusting cylinder 4011 on one side of the side mold before pouring is set to f. 1,0 The initial support force of the inclined adjusting cylinder 4012 on the diagonal mold 4003 before pouring is set to f. 2,0 Set the length L of side plate 4002 and the length l of corner mold 4003;

[0068] S4. Construct a three-dimensional control model and dynamically generate the target support force f. i (h,t) n (i = 1, 2), that is, the relationship between pouring height, time and target support force during the pouring process:

[0069]

[0070] Where f1(h,t) represents the target support force of the lateral adjustment cylinder 4011, which is used to balance the concrete lateral pressure on the side plate 4002; f2(h,t) represents the target support force of the oblique adjustment cylinder 4012, which is used to resist the concrete lateral pressure of the outward expansion of the corner mold 4003; n represents the number of support adjustment units 401 axially set on the main beam 411.

[0071] k1 and k2 represent the side plate bending moment balance coefficient and the corner modulus force decomposition coefficient, respectively;

[0072] α(t) is the side plate correction coefficient, β(t) is the corner mold correction coefficient; h is the real-time casting height;

[0073] Regarding the stress analysis of side plate 4002: Assuming a constant and uniform pouring speed, the lateral pressure is simplified to hydrostatic pressure P(h) = ρgh. Side plate 4002 is subjected to a trapezoidal distributed load, and the maximum bending moment is at the midpoint of side plate 4002.

[0074]

[0075] The supporting force f1(h,t) of the lateral adjusting cylinder 4011 n To balance the bending moment, then Determine the moment balance coefficient of side plate 4002

[0076] Regarding the force analysis of the corner mold 4003, in its initial state, the corner mold 4003 forms an angle α with the horizontal plane. The resultant force on the corner mold 4003 is decomposed into a normal force N and a tangential force T. The corner mold 4003 forms an angle of 180°-α with the side mold.

[0077] N=P(h)·l·sin(180°-a)=P(h)·l·sin a

[0078] The supporting force f2(h,t) of the inclined adjusting cylinder 4012 n ≥N·cos a=ρghl·sin a·cos a, in this embodiment, the angle between the angle modulus 4003 and the horizontal plane is initially α=45°, simplified The force decomposition coefficient of the angle modulus 4003 in this embodiment can be determined.

[0079] The above is f1(h,t) n and f2(h,t) n It is the core dynamic support force function in the deformation control method of precast drainage box culvert steel formwork, corresponding to the real-time control requirements of the lateral adjustment cylinder 4011 and the oblique adjustment cylinder 4012 respectively. Based on the theoretical model of concrete lateral pressure and combined with time-related correction coefficients, intelligent control is achieved through sensor feedback and PID algorithm, ultimately ensuring that the deformation of the formwork is controllable during the pouring process, avoiding grout bursting and structural failure;

[0080] S5. Real-time monitoring and data acquisition: Real-time monitoring of the oil pressure of the lateral adjustment cylinder 4011 and the oblique adjustment cylinder 4012 during the pouring process; acquisition of values ​​from the first and second pressure sensors to obtain the measured oil pressure; conversion of the measured support force to obtain the actual support force; dynamic calculation of the target support force f. i (h,t)n By comparing the measured support force with the actual support force, it can be determined whether the support meets the standard under the current pouring condition;

[0081] S6. Adjustment and control of the pouring process: Based on the measured support force exceeding the target support force f i (h,t) n The degree of control is adjusted by combining the PID algorithm to regulate the oil pressure of the hydraulic cylinder until the measured support force f is reached. i,实 It meets the support requirements.

[0082] In the preferred embodiment, the PID algorithm controls the oil pressure of the hydraulic cylinder in step S6, and the specific steps are as follows:

[0083] S61. Calculate the error value between the measured support force and the target support force:

[0084] e i (t) n =f i (h,t) n -f i,实

[0085] Set the error value e i (t) n The threshold for exceeding the limit is e max If the actual supporting force exceeds the design threshold, it will cause the template to deform or the assembly to fail. The error threshold is determined as follows:

[0086] When e i (t) n <0, the supporting force of the lateral adjusting cylinder 4011 or the oblique adjusting cylinder 4012 meets the standard, and no PID adjustment is required;

[0087] When 0<e i (t) n ≤e max Perform PID control;

[0088] When e i (t) n >e max If this occurs, the machine should be stopped immediately and the assembly of side plate 4002 and corner mold 4003 should be checked.

[0089] S62, PID control:

[0090] Initialize PID parameters: PID parameters include the proportional constant K p Integral constant K i Differential constant K d ;

[0091] Calculate the adjustment amount based on the PID control algorithm:

[0092]

[0093] In the formula, Δf i (t) n K is the PID control variable. p K is a proportionality constant. i K is the integration constant. d It is a differential constant;

[0094] S63. Adjust the oil pressure of the hydraulic cylinder: according to the PID control value Δf i (t) n Adjust the oil pressure of the lateral adjustment cylinder 4011 and the oblique adjustment cylinder 4012; if the error deviation of the two side plates 4002 or the two corner molds 4003 is >5%, prioritize adjusting the cylinder on the side with lower support force to achieve symmetrical compensation.

[0095] S65. Real-time monitoring and feedback: Real-time monitoring of the oil pressure in the cylinder mentioned in step S2 is performed and fed back to the PID controller for closed-loop control. Based on the actual control effect, the parameter K of the PID control algorithm is gradually adjusted. p K i and K d In order to achieve the best control effect.

[0096] This embodiment employs a PID algorithm as the core method for inner-loop control, which can monitor the oil pressure of the lateral adjustment cylinder 4011 and the oblique adjustment cylinder 4012 in real time and quickly calculate the error value between the measured support force and the target support force. Based on the error value, the PID controller accurately calculates the adjustment amount of the cylinder oil pressure according to preset proportional, integral, and derivative parameters, and promptly adjusts the extension and retraction of the cylinders to make the measured support force quickly approach the target support force.

[0097] In a preferred embodiment of this invention, after the prefabricated drainage culvert steel formwork is assembled and before pouring, the hydraulic system applies a designed preload to a stable state, forming the initial state. The values ​​of the first and second pressure sensors are recorded at this time, corresponding to the initial oil pressure P of the transverse adjusting cylinder 4011 before pouring. 1,0 The initial oil pressure P of the inclined adjusting cylinder 4012 before pouring 2,0 Calculate f 1,0 and f 2,0 It satisfies the following relationship:

[0098] f 1,0 =P 1,0 ·A1·η

[0099] f 2,0 =P 2,0 ·A2·COSθ·η

[0100] where, η: mechanical efficiency of the hydraulic system, with a value range of 0.9 - 0.95, dimensionless; A1: effective area of the piston of the lateral adjustment cylinder 4011, m 2 ; A2: effective area of the piston of the diagonal adjustment cylinder 4012, m 2 ; θ is the installation angle of the diagonal adjustment cylinder 4012.

[0101] Before construction, based on parameters such as the design requirements of the formwork system, the structural strength of the side form 4002 and the corner form 4003, and the expected concrete lateral pressure, a reasonable initial support force range is preset, and a rough initial oil pressure is set; then after the formwork installation is completed, by collecting the actual oil pressure and calculating the initial support force, the preset initial oil pressure is finely adjusted and verified to ensure that the formwork system is in the best initial state before pouring, so as to meet the deformation control requirements of the precast drainage culvert steel formwork during pouring construction. The initial support force is a static pre-tightening force preset before the start of pouring (h = 0, time t0), which is used to offset the self-weight of the formwork, assembly stress and minor disturbances in the initial stage of construction, and ensure the stability of the formwork structure.

[0102] Determining a suitable initial support force in advance can accurately pre-adjust the formwork system before pouring, making the formwork in an ideal design state and providing stable initial conditions for the subsequent pouring process.

[0103] In the preferred implementation mode of this embodiment, the correction coefficient α(t) of the side formwork 4002 and the correction coefficient β(t) of the corner formwork 4003 are determined by the hierarchical control method, and are divided into three pouring stages according to the pouring height h:

[0104] Pouring stage I: h ≤ 0.2H, focusing on the adjustment of the corner formwork 4003, taking α(t) = 0.8, β(t) = 0.6; this stage can inhibit the outward expansion of the formwork caused by the fluidity of the concrete;

[0105] Pouring stage II: 0.2H < h ≤ 0.5H, the side formwork 4002 and the corner formwork 4003 are adjusted synchronously, taking α(t) = 1.0, β(t) = 0.9; matching the uniform distribution of the load;

[0106] Pouring stage III: h > 0.5H, focusing on the adjustment of the side formwork 4002, taking α(t) = 1.2, β(t) = 1.1; strengthening the support of the side formwork 4002 to resist the cumulative bending moment at the bottom.

[0107] The above-mentioned layered control method is based on the lateral pressure distribution and structural mechanical properties to divide the stage. It dynamically adjusts the correction coefficients of the lateral and oblique adjustment cylinders 4012, and accurately matches the evolution law of the formwork stress during the concrete pouring process by matching the nonlinear distribution characteristics of the concrete lateral pressure in stages, thereby optimizing the distribution of support force. In practical applications, it can significantly reduce the risk of grout leakage and control the deformation of the formwork, with deflection ≤ L / 600. It is an intelligent control strategy that takes into account both theoretical rigor and engineering practicality.

[0108] In a preferred embodiment of this example, step S2 further includes the deployment of a displacement monitoring unit, including a laser rangefinder and an inclination sensor. The laser rangefinder is positioned at the midpoint of the side plate 4002 to monitor the midpoint deflection δ of the side plate 4002. The inclination sensor is positioned outside the hinge point between the corner mold 4003 and the side plate 4002 to monitor the change in the opening and closing angle Δθ of the corner mold 4003.

[0109] When the opening and closing angle of the angle modulus 4003 changes by Δθ > 1°, adjust the differential coefficient and increase it by (20% to 30%)·K. d Since the abnormal opening angle of corner mold 4003 indicates uneven distribution of lateral pressure in the concrete, it may lead to grout leakage at the joint or structural misalignment. The above adjustment strategies can enhance the ability to predict the trend of angle changes, suppress the outward expansion trend in advance, and quickly eliminate angle deviation to prevent cumulative errors; reduce angle fluctuations and improve the symmetry of the structure on both sides of corner mold 4003.

[0110] Furthermore, the preset warning threshold for midpoint deflection is L / 800. When the midpoint deflection δ of side plate 4002 is ≥ L / 800, additional force compensation is triggered. Where γ is a proportionality coefficient, dimensionless, and in this embodiment, γ = 0.1; f1 is the current supporting force, which is the target supporting force f1(h,t). n The current value; L is the length of side plate 4002.

[0111] To prevent further deformation, the hydraulic system automatically increases the support force and dynamically compensates when the deformation exceeds the limit by monitoring the deflection δ in real time. The square term ensures a rapid response to significant deformation while avoiding oversensitivity to small deviations. The additional force increases non-linearly with the degree of exceedance, accurately suppressing large deformations. The additional force compensation strategy, namely displacement compensation, serves as the outer loop control. It dynamically corrects the target support force based on deflection feedback, forming a closed loop control. Combined with the inner loop PID control, it realizes an intelligent control cycle of "monitoring-calculation-adjustment," ensuring the stability of the formwork and construction safety.

[0112] In a preferred embodiment of this invention, the prefabricated drainage box culvert steel formwork includes end molds 1, outer molds 5, inner mold assemblies 4, and a platform 3. The box culvert foundation, formed by reinforcing steel binding, is placed on the platform 3. The inner mold assembly 4 is located within the inner cavity of the box culvert foundation. The outer molds 5 are located on both sides of the box culvert foundation. The end molds 1 are located at both axial ends of the box culvert foundation. An inner mold support 2 is placed on each side of the platform 3. The inner mold assembly 4 includes an inner mold, a walking system 41, and a hydraulic system. The walking system 41 includes a main beam 411 and a walking device 412. The main beam 411 is located on the platform 3. The upper part and both ends of the main beam 411 are supported on the inner mold support 2. The walking device 412 is located at both ends of the bottom of the main beam 411 and between the two inner mold supports 2. The inner mold body is formed by installing a corresponding number of inner template units 400 according to the preset number along the axial direction of the main beam 411. The inner mold 40 also includes a mold-collecting device 402. The inner mold body is axially and evenly spaced with support adjustment units 401 and mold-collecting devices 402. Each mold-collecting device 402 is controlled by a hydraulic system to adjust the side plate 4002 and the corner mold 4003 into place.

[0113] In a preferred embodiment of this example, the inner mold 40 further includes a temporary support unit (not shown in the figure). A support adjustment unit 401, a temporary support unit, and a mold closing device 402 are arranged axially and evenly within the inner mold body. The temporary support unit includes transverse struts and diagonal struts. The diagonal struts are located between the bottom of the corner mold 4003 and the main beam 411. A pair of symmetrical side plates 4002 are further supported by the transverse struts. It is worth noting that in this embodiment, the temporary support unit and the support adjustment unit have the same structure. The transverse struts replace the transverse adjustment cylinder 4011 in the support adjustment unit, and the diagonal struts replace the diagonal adjustment cylinder 4012. This forms a temporary support structure that only provides support force without adjustment function. It can be arranged as needed along the axial direction of the box culvert to flexibly meet construction requirements.

[0114] Furthermore, the side plate 4002 has an inclined section 40021 and a vertical section 40022. The two sides of the side plate 4002 are symmetrically connected to one end of the inclined section 40021. One end of the vertical section 40022 of each side plate 4002 is symmetrically hinged to the corner mold 4003. The mold-collecting device 402 includes a first mold-collecting cylinder 4021 and a second mold-collecting cylinder 4022. The inclined section 40021 is opposite to the corner mold 4003 and the first mold-collecting cylinder 4021 is provided between them. The vertical section 40022 is connected to the side of the main beam 411 through the second mold-collecting cylinder 4022.

[0115] In this embodiment, the inner mold is applied to a double-cavity precast drainage box culvert. Each cavity is equipped with a combination of a temporary support unit, a support adjustment unit 401, and a mold-collecting device 402 arranged at intervals. The two cavities in the same cross-sectional plane are equipped with the same device. That is, a pair of symmetrical temporary support units, support adjustment units 401, or mold-collecting devices 402 are set between the two cavities in the same cross-section. In other words, in the same cross-section, such as the DD cross-section, the temporary support unit or support adjustment unit 401 adopted adopts a symmetrical force design in the corresponding cross-sectional plane. The two opposite inner molds in the temporary support unit in a single cavity are supported by transverse struts, and the two symmetrical corner molds 4003 are symmetrically supported by diagonal struts, forming a symmetrical force system to offset the lateral load. Considering that the overall support system needs to meet the stress balance during pouring, in this embodiment, the inner formwork forms a support system for the inner cavity of the box culvert by sequentially and spaced support adjustment units 401, temporary support units, and formwork collection devices 402 along the axial direction of the main beam 411. Each temporary support unit, support adjustment unit 401, or formwork collection device 402 forms a symmetrical support ring for the inner cavity of the box culvert. The dense distribution forms a tight stress distribution, reducing the deformation caused by local stress points. This achieves the flatness requirements and deformation control of the formwork at a lower cost. At the same time, this embodiment does not rely on concrete strength for stress conversion and directly optimizes the stress path through structural design.

[0116] The embodiments of the present invention have been described in detail above with reference to the accompanying drawings, but the present invention is not limited to the described embodiments. For those skilled in the art, various changes, modifications, substitutions, and variations can be made to these embodiments without departing from the principles and spirit of the present invention, and these variations still fall within the protection scope of the present invention.

Claims

1. A method for controlling deformation during the casting construction of precast drainage box culvert steel formwork, characterized in that... It includes the following steps: S1. Establish the initial state: Assemble and debug the inner mold assembly, outer mold and end mold of the precast drainage culvert steel formwork to form the initial state; S2. Layout the monitoring points: Layout monitoring points in the inner mold assembly, install pressure sensors, and measure the oil pressure; S3. Set the initial parameters; The inner mold assembly, outer mold and end mold are assembled to form the cavity to be poured, and the initial supporting force of the inner mold assembly on the cavity to be poured before pouring is set; S4. Construct a three-dimensional control model: Dynamically generate the target supporting force, that is, the relationship between the pouring height, time and the target supporting force during the pouring process: S5. Real-time monitoring and data collection: Real-time monitor the values of the pressure sensors during the pouring process, obtain the measured oil pressure, and convert it to the measured supporting force; Dynamically calculate the target supporting force, compare it with the measured supporting force, and judge whether the support meets the standard under the current pouring state; S6. Adjustment and control during the pouring process: According to the degree to which the measured supporting force exceeds the target supporting force, combine the PID algorithm to regulate the oil pressure of the oil cylinder until the measured supporting force meets the support requirements.

2. The deformation control method for precast drainage box culvert steel formwork casting construction according to claim 1, characterized in that... It includes the following steps: S1. Establish the initial state: Assemble and debug the inner mold assembly, outer mold and end mold of the precast drainage culvert steel formwork. The inner mold assembly includes an inner mold, and the inner mold includes an inner template unit and a support adjustment unit. The inner template unit includes a top plate, side plates and corner molds. The top plate is arranged on the top surface of the main beam cross-section. One end of each side plate is symmetrically hinged on both sides of the top plate, and the other end of each side plate is symmetrically hinged with a corner mold. The support adjustment unit includes a horizontal adjustment oil cylinder and an inclined adjustment oil cylinder. The horizontal adjustment oil cylinder is arranged between the two side plates, and each corner mold is connected to the bottom of the main beam through an inclined adjustment oil cylinder. The horizontal adjustment oil cylinder and the inclined adjustment oil cylinder are controlled by a hydraulic system to form the initial state; S2. Layout the monitoring points: First pressure sensors are arranged at the hinge points of both ends of the horizontal adjustment oil cylinder and the side mold to determine the side plate monitoring points; Second pressure sensors are arranged at the hinge points of the inclined adjustment oil cylinder end and the corner mold to determine the corner mold monitoring points; S3. Set the initial parameters: The design height of the cavity to be poured is set to H; the initial support force of the lateral adjustment cylinder on one side of the side formwork before pouring is set to f. 1,0 The initial support force of the inclined adjusting cylinder on the diagonal mold before pouring is set to f. 2,0 Set the side plate length L and the corner mold length l; S4. Construct a three-dimensional control model: dynamically generate the target support force f. i (h,t) n (i = 1, 2), that is, the relationship between pouring height, time and target support force during the pouring process: Where, f1(h,t) n This represents the target support force of the lateral adjustment cylinder; f2(h,t) n This represents the target support force of the inclined adjustment cylinder, and n represents the number of support adjustment units set along the axial direction of the main beam. k1 and k2 respectively represent the side plate bending moment balance coefficient and the corner mold force decomposition coefficient; α(t) is the side plate correction coefficient, β(t) is the corner mold correction coefficient; h is the real-time pouring height; S5. Real-time monitoring and data acquisition: Real-time monitoring of the oil pressure of the lateral and oblique adjustment cylinders during the pouring process; acquisition of values ​​from the first and second pressure sensors to obtain the measured oil pressure; conversion of the measured support force to obtain the actual support force; dynamic calculation of the target support force f. i (h,t) n By comparing the measured support force with the actual support force, it can be determined whether the support meets the standard under the current pouring condition; S6. Adjustment and control of the pouring process: Based on the measured support force exceeding the target support force f i (h,t) n The degree of control is adjusted by combining the PID algorithm to regulate the oil pressure of the hydraulic cylinder until the measured support force f is reached. i,实 It meets the support requirements.

3. The deformation control method for precast drainage box culvert steel formwork casting construction according to claim 2, characterized in that, For the PID algorithm to regulate the oil pressure of the oil cylinder in step S6, the specific steps are as follows: S61. Calculate the error value between the measured supporting force and the target supporting force: e i (t) n =f i (h,t) n -f i,实 Set the error value e i (t) n The threshold for exceeding the limit is e max If the actual supporting force exceeds the design threshold, it will cause the template to deform or the assembly to fail. The error threshold is determined as follows: When e i (t) n <0, the supporting force of the lateral or oblique adjusting cylinder meets the standard, and no PID adjustment is required; When 0<e i (t) n ≤e max Perform PID control; When e i (t) n >e max If this occurs, the machine must be stopped immediately and the assembly of the side panels and corner molds must be checked. S62. PID adjustment: Initialize PID parameters: PID parameters include the proportional constant K p Integral constant K i Differential constant K d ; Calculate the adjustment amount according to the PID control algorithm: In the formula, Δf i (t) n K is the PID control variable. p K is a proportionality constant. i K is the integration constant. d It is a differential constant; S63. Adjust the oil pressure of the hydraulic cylinder: according to the PID control value Δf i (t) n Adjust the oil pressure of the lateral adjusting cylinder and the oblique adjusting cylinder; S65. Real-time monitoring and feedback: Real-time monitoring of the oil pressure in the cylinder mentioned in step S2 is performed and fed back to the PID controller for closed-loop control. Based on the actual control effect, the parameter K of the PID control algorithm is gradually adjusted. p K i and K d In order to achieve the best control effect.

4. The deformation control method for the casting construction of precast drainage box culvert steel formwork according to claim 2, characterized in that: After the prefabricated drainage culvert steel formwork is assembled and before pouring, the hydraulic system applies the designed preload to a stable state, forming the initial state. The values ​​of the first and second pressure sensors are recorded at this time, which correspond to the initial oil pressure P of the lateral adjustment cylinder before pouring. 1,0 The initial oil pressure P of the inclined adjustment cylinder before pouring 2,0 Calculate f 1,0 and f 2,0 It satisfies the following relationship: f 1,0 =P 1,0 ·A1·η f 2,0 =P 2,0 ·A2·COSθ·η Where η: mechanical efficiency of the hydraulic system, ranging from 0.9 to 0.95, dimensionless; A1: effective area of ​​the piston of the lateral adjusting cylinder, in meters. 2 A2: Effective piston area of ​​the inclined adjustment cylinder, m 2 θ is the installation angle of the inclined adjustment cylinder.

5. The deformation control method for the casting construction of precast drainage box culvert steel formwork according to claim 2, characterized in that, The side plate correction coefficient α(t) and the corner mold correction coefficient β(t) are determined by the hierarchical control method, and are divided into three pouring stages according to the pouring height h: Pouring stage I: h≤0.2H, focusing on the adjustment of the corner mold, take α(t)=0.8, β(t)=0.6; Pouring stage II: 0.2H<h≤0.5H, synchronously adjusting the side plate and the corner mold, take α(t)=1.0, β(t)=0.9; Pouring stage III: h>0.5H, focusing on the adjustment of the side plate, take α(t)=1.2, β(t)=1.

1.

6. The deformation control method for precast drainage box culvert steel formwork casting construction according to claim 3, characterized in that: Step S2 also includes the deployment of a displacement monitoring unit, including a laser rangefinder and an inclination sensor. The laser rangefinder is positioned at the midpoint of the aligned side plate to monitor the midpoint deflection δ of the side plate. The inclination sensor is positioned outside the hinge point between the corner mold and the side plate to monitor the angle change Δθ of the corner mold opening and closing. When the angle of opening and closing of the corner modulus changes by Δθ > 1°, it triggers the adjustment of the differential coefficient, increasing it by (20%–30%)·K. d .

7. The deformation control method for precast drainage box culvert steel formwork casting construction according to claim 6, characterized in that: The preset warning threshold for midpoint deflection is L / 800. When the midpoint deflection δ of the side plate is greater than or equal to L / 800, additional force compensation is triggered. Where γ is the proportionality constant, which is dimensionless; f1 represents the current supporting force, while f1(h,t) represents the target supporting force. n The current value; L is the length of the side plate.

8. The deformation control method for the casting construction of precast drainage box culvert steel formwork according to claim 2, characterized in that: The precast drainage box culvert steel formwork includes end molds, outer molds, inner mold assemblies, and a platform. The box culvert foundation, formed by steel reinforcement binding, is placed on the platform. The inner mold assembly is placed inside the box culvert foundation. The outer molds are placed on both sides of the box culvert foundation, and the end molds are placed at both ends of the box culvert foundation along its axial direction. An inner mold support is placed on each side of the platform. The inner mold assembly includes the inner mold, a walking system, and a hydraulic system. The walking system includes a main beam and a walking device. The main beam is placed directly above the platform, with both ends of its bottom supported on the inner mold supports. The walking device is placed at both ends of the bottom of the main beam and between the two inner mold supports. A corresponding number of inner mold units are installed along the axial direction of the main beam according to a preset number to form the inner mold body. The inner mold also includes a mold-collecting device. Support adjustment units and mold-collecting devices are evenly spaced along the axial direction of the inner mold body. Each mold-collecting device is controlled by the hydraulic system to adjust the side plates and corner molds into position.

9. The deformation control method for the casting construction of precast drainage box culvert steel formwork according to claim 8, characterized in that: The inner mold also includes a temporary support unit. The support adjustment unit, the temporary support unit and the mold closing device are arranged axially and evenly in sequence within the inner mold body. The temporary support unit includes a transverse strut and a diagonal strut. The diagonal strut is located between the bottom of the corner mold and the main beam. A pair of symmetrical side plates are supported by the transverse strut.

10. A deformation control method for the casting construction of precast drainage box culvert steel formwork according to claim 8 or 9, characterized in that: The side plate has an inclined section and a vertical section. The two sides of the side plate are symmetrically connected to one end of the inclined section of the side plate. One end of the vertical section of each side plate is symmetrically hinged to the corner mold. The mold-retracting device includes a first mold-retracting cylinder and a second mold-retracting cylinder. The inclined section is opposite to the corner mold and the first mold-retracting cylinder is provided between them. The vertical section is connected to the side of the main beam through the second mold-retracting cylinder.

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