BIM-based adjustable angle shear wall construction joint inner formwork support method

Abstract

The present application relates to the field of building construction technology, disclose a kind of adjustable angle shear wall construction joint inner mold support method based on BIM, comprising: using BIM software to carry out kinematics simulation to the physical parameters of multi-chamber hollow EPDM rubber strip;Transmission main shaft, linkage auxiliary shaft and hydraulic jack are assembled to form transmission framework, connect aluminum alloy formwork and assemble the rubber strip on both side edges, form inner mold support system;Hydraulic jack is retracted after the system is hoisted into restricted operation space and is in place;Hydraulic jack drives transmission framework to open formwork to target angle, and rubber strip extrusion existing concrete wall surface;After forming completely rigid lock structure, pour self-compacting concrete, utilize lateral pressure to force rubber strip to stick to wall surface;After concrete strength reaches specification requirement, unload hydraulic thrust to make system contract and extract demoulding.The present application solves the problem that formwork is difficult to adjust and prone to slurry leakage in restricted space.

Description

Technical Field

[0001] This invention relates to the field of building construction technology, specifically to a BIM-based method for supporting the internal formwork of construction joints in adjustable-angle shear walls. Background Technology

[0002] During building construction, the internal formwork support work at shear wall construction joints often faces limitations in confined spaces, such as those with non-parallel double walls. Traditional internal formwork support structures have relatively fixed structures and volumes, making it difficult to insert or remove them entirely into narrow construction spaces. This fixed formwork structure cannot adjust the support angle according to the actual angle of the existing walls on site, resulting in significant difficulties in assembly, positioning, and demolding operations within confined spaces.

[0003] Meanwhile, when pouring self-compacting concrete at construction joints, the edges of the formwork must maintain a tight seal with the existing concrete wall. Existing conventional edge sealing methods often experience grout leakage at the construction joint edges due to uneven stress or inadequate sealing when subjected to the lateral pressure of poured concrete. Furthermore, traditional sealing strips are prone to irreversible plastic deformation under continuous pressure from the wall, failing to return to their initial cross-sectional state after unloading and demolding, making it difficult to meet the requirements of continuous reuse in engineering projects.

[0004] Furthermore, when self-compacting concrete is poured in layers and subjected to high-frequency vibration with a vibrator, it exerts outward lateral compressive forces on the formwork system. Existing adjustable internal formwork support structures, when subjected to such lateral compressive forces, are prone to stress yielding or displacement deformation due to the lack of a fully rigid locking mechanism between the internal transmission components. This results in deviations in the cross-sectional dimensions of the concrete after molding, failing to guarantee the quality of the components at construction joints. Summary of the Invention

[0005] To address the shortcomings of existing technologies, this invention provides a BIM-based method for supporting the internal formwork of construction joints in shear walls. This method solves the problems of existing non-parallel double-wall narrow working spaces where the formwork is difficult to adaptively adjust the support angle, installation and demolding operations are difficult, and the edge of the construction joint is not tightly fitted, which can easily lead to grout leakage.

[0006] To address the above problems, the present invention provides the following technical solution: This invention provides a BIM-based method for supporting the internal formwork of construction joints in adjustable-angle shear walls, comprising: A three-dimensional digital model was constructed using BIM software, and the physical parameters of the multi-chamber hollow EPDM rubber strip were input for kinematic simulation, so that the simulated compression value was within the elastic recovery range. Assemble the main drive shaft and the secondary drive shaft, and connect them with hydraulic jacks to form a transmission frame; Square steel main ribs and U-shaped steel channel secondary ribs are welded to the back of the aluminum alloy template, and multi-chamber hollow EPDM rubber strips are installed on both sides of the aluminum alloy template. The connecting transmission frame and the aluminum alloy template form the inner mold support system; After retracting the inner mold support system using hydraulic jacks, it is hoisted into place in the working space; The hydraulic jack pushes the transmission frame to open the aluminum alloy templates on both sides to the target angle, so that the hollow EPDM rubber strips in the multi-chamber can compress the existing concrete wall surface. A completely rigid locking structure is formed, and self-compacting concrete is poured. The lateral pressure generated by the pouring is used to compress the multi-chamber hollow EPDM rubber strip to adhere tightly to the existing concrete wall. After the self-compacting concrete reaches the required strength, the hydraulic jacks are unloaded to allow the aluminum alloy formwork to shrink, and finally the inner formwork support system is removed for demolding.

[0007] Input the physical parameters of the multi-chamber hollow EPDM rubber strip for kinematic simulation, ensuring that the simulated compression value is within the elastic recovery range. This includes the following steps: The included angle between the non-parallel double walls is extracted from the 3D digital model. In the kinematic simulation, the compressive deformation rate of the multi-chamber hollow EPDM rubber strip under the pressure of the existing concrete wall is calculated as the compression value. Deformation data for the maximum and minimum design angles are retrieved, and the compression values ​​of the multi-chamber hollow EPDM rubber strip are compared to see if they fall within the material's elastic recovery range. If the compression value exceeds the elastic recovery range, the cross-sectional thickness of the multi-chamber hollow EPDM rubber strip (a physical parameter) is modified in the BIM software, and the kinematic simulation is repeated until all simulated compression values ​​fall within the elastic recovery range.

[0008] When assembling the multi-chamber hollow EPDM rubber strip, a metal dovetail groove is welded along the longitudinal length of both edges where the aluminum alloy formwork contacts the existing concrete wall. A multi-chamber hollow EPDM rubber strip with an inverted trapezoidal cross-section on one side and a V-shaped unidirectional flow-guiding lip on the other is selected. The inverted trapezoidal side of the multi-chamber hollow EPDM rubber strip is slid into and secured along the metal dovetail groove. No adhesive is used during the assembly process, and the V-shaped unidirectional flow-guiding lip opening is kept facing the internal space of the self-compacting concrete to be poured.

[0009] When assembling the main drive shaft and the linkage shaft, the hinge position is marked on the surface of the round steel tube that serves as the main drive shaft. One end of the linkage shaft is welded to the shaft connecting sleeve, and a supporting steel plate is welded to the tail of the linkage shaft. The connection is made by fitting the shaft connecting sleeve onto the hinge position on the surface of the main drive shaft, thus setting a movable hinge point. Multiple linkage shafts are installed sequentially along the circumference and length of the main drive shaft. A connecting square steel is fully welded coaxially to one end of the main drive shaft to form a radial umbrella-shaped frame. The hydraulic jack is then connected to the connecting square steel.

[0010] After retracting the inner mold support system using hydraulic jacks, the mold is hoisted into place in the work space, including the following specific steps: The supporting steel plate at the end of the linkage sub-shaft is embedded into the U-shaped steel channel secondary rib on the back of the aluminum alloy formwork to complete the hinged assembly. The hydraulic jack is unloaded, causing the drive main shaft to retract. The linkage sub-shaft pulls the aluminum alloy formwork on both sides inward, continuing the retraction until the inner formwork support system reaches its minimum volume. The base layer of the construction joint interface is cleaned, roughened, and residual concrete debris is removed. Corner positioning lines are marked on the ground according to the layout drawings. The retracted inner formwork support system is lifted using lifting equipment, moved horizontally into the confined work space, and vertically lowered according to the corner positioning lines marked on the ground, completing the lifting and spatial positioning.

[0011] The hydraulic jack pushes the transmission frame to open the aluminum alloy templates on both sides to the target angle, including the following specific steps: Power is supplied to the hydraulic jack, causing its push rod to extend forward and push the connecting square steel and the main drive shaft forward. The main drive shaft moves forward axially, generating axial thrust, which pulls multiple linkage shafts through the movable hinge points. Under this force, the linkage shafts extend outward, converting the axial thrust into a radial spreading force pointing outwards on both sides, pushing the aluminum alloy templates on both sides outwards until they reach the target angle. As the aluminum alloy templates open outwards, the multi-chamber hollow EPDM rubber strips undergo elastic deformation under pressure, filling the uneven areas on the existing concrete wall surface.

[0012] To form a fully rigid locked structure, the following specific steps are involved: After the aluminum alloy formwork on both sides is fully extended, a laser plumb line is used to check and verify its verticality. At the intersection of the linkage sub-shaft and the main square steel rib, limit pins and high-strength bolts are inserted. Simultaneously, a limit device is fabricated using 16mm-22mm diameter round steel bars. One end of the limit device is connected to a U-shaped steel channel secondary rib, and the other end is connected to a hydraulic jack. This limits and fixes the extension and retraction of the hydraulic jack, converting the supporting force maintained by the hydraulic jack into a completely rigid locking structure. After locking, holes are drilled along the corner positioning line on the outside of the aluminum alloy formwork, and short steel bars are inserted to complete supplementary positioning and reinforcement.

[0013] Pouring self-compacting concrete includes the following specific steps: Within the cavity formed by the double walls, the surface of the aluminum alloy formwork is moistened with water, and self-compacting concrete is poured using a layered pouring process. As the pouring liquid level rises, high-frequency vibration is applied using a vibrator, causing the unset self-compacting concrete to generate lateral pressure on the outside of the aluminum alloy formwork. This lateral pressure directly compresses the inner side of the V-shaped unidirectional guide lip of the multi-chamber hollow EPDM rubber strip, forcing the V-shaped unidirectional guide lip to open outward and tightly press against the existing concrete wall surface. With the increase in the pouring liquid level and the effect of high-frequency vibration, the lateral pressure increases synchronously, and the compressive force pressing the V-shaped unidirectional guide lip against the existing concrete wall surface increases proportionally.

[0014] Demolding involves removing the inner mold support system, including the following specific steps: After the self-compacting concrete reaches the required strength, remove the limiting pins, high-strength bolts, and limiting devices. Reconnect and slightly pressurize the hydraulic jacks to loosen the construction joint surfaces. Then, unload the hydraulic thrust of the jacks, causing the main drive shaft to retract, pulling the linkage shaft back and simultaneously causing the aluminum alloy formwork on both sides to retract inwards. Once the inner formwork support system is fully retracted, smoothly pull it out from one end to the other along the cavity formed inside the non-parallel double walls. Clean the residual mortar on the surface of the inner formwork support system and apply a release agent.

[0015] In the above method, the material parameters are limited to meet the following conditions: The main drive shaft uses a round steel pipe with a diameter of 35mm-50mm and a wall thickness of 2mm-4mm; the linkage secondary shaft uses a round steel pipe with a diameter of 12mm-20mm; the main square steel rib uses square steel with a cross-sectional size of (50-70)mm×(30-50)mm and a wall thickness of 2mm-4mm; the secondary U-shaped steel channel uses U-shaped steel channel with a cross-sectional size of (40-60)mm×(2-4)mm; the load is not less than 5KN and the stroke is greater than 100mm; the thickness of the aluminum alloy template is 5.0mm-8.0mm.

[0016] This invention provides a BIM-based method for supporting the internal formwork of construction joints in adjustable-angle shear walls. It offers the following advantages: 1. This invention connects the main drive shaft, the linkage secondary shaft, and a hydraulic jack to form a transmission frame. The hydraulic jack drives the main drive shaft and the linkage secondary shaft, causing the aluminum alloy templates on both sides to retract inwards. This facilitates the hoisting of the inner mold support system into narrow, confined working spaces. After positioning, hydraulic power is used again to open the template outwards to the target angle, meeting the variable angle support requirements of non-parallel double walls and solving the operational difficulties of template assembly, angle adjustment, and demolding in confined spaces.

[0017] 2. This invention assembles multi-chamber hollow EPDM rubber strips with V-shaped unidirectional flow guide lips along the edges of aluminum alloy formwork. During the pouring of self-compacting concrete, the lateral pressure generated by the unset concrete compresses the V-shaped unidirectional flow guide lips, causing them to open outwards and adhere tightly to the existing concrete wall surface. As the pouring liquid level rises, the extrusion pressure increases synchronously, achieving dynamic sealing and preventing grout leakage. Prior to this, kinematic simulations were performed using BIM software to control the compression deformation of the rubber strip within its elastic recovery range, ensuring that the sealing material can recover its original shape and be reused after demolding.

[0018] 3. After the aluminum alloy formwork is stretched into place, the present invention inserts a limiting pin and a high-strength bolt at the cross connection position of the linkage sub-shaft and the square steel main rib, and combines the limiting device to fix the extension stroke of the hydraulic jack. This converts the supporting force maintained by the hydraulic jack into a completely rigid locking structure, which can effectively resist the lateral pressure generated during concrete pouring and high-frequency vibration, avoid the formwork system from collapsing or deforming, and ensure the dimensional accuracy of the concrete forming at the construction joint. Attached Figure Description

[0019] Figure 1 This is a flowchart of a BIM-based adjustable angle shear wall construction joint internal formwork support method according to an embodiment of the present invention. Figure 2 This is a schematic diagram of the overall structure and sensor arrangement of a lifting device according to an embodiment of the present invention, wherein (a) is a comparison diagram of slurry leakage volume, (b) is a comparison diagram of molding quality deviation values, and (c) is a comparison diagram of demolding and cleaning time. Figure 3 The following is a comparison chart of the effectiveness test of Embodiment 1 and Comparative Example 2 of the present invention at different pouring heights, wherein (a) is a trend chart of cumulative grout leakage, and (b) is a comparison chart of demolding pull-out resistance. Figure 4 The diagram shows a comparison of the load-bearing stability and energy consumption of Embodiment 1 and Comparative Example 3 during the dynamic casting process. (a) is a trend diagram of the end displacement, and (b) is a trend diagram of the cumulative energy consumption. Detailed Implementation

[0020] The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0021] Please see the appendix Figure 1 This invention provides a BIM-based method for supporting the internal formwork of adjustable-angle shear wall construction joints, comprising the following steps: S1. Use BIM software to construct a high-precision 3D digital model of the construction joint of the non-parallel shear wall and the surface of the existing wall. Extract the included angle of the double walls and the spatial depth dimensions from the model. Input the physical parameters of the hollow rubber strip at the edge into the model to simulate the compression deformation rate under the supporting action, ensuring that the compression amount is maintained within the elastic recovery range under extreme working conditions; S2. Based on the geometric parameters derived in the previous step, select round steel pipes and square steel for cutting. Hinge the drive shaft and the linkage shaft together, and fully weld the square steel to one end of the drive shaft along the same axis to form a radial umbrella-shaped frame. Connect the hydraulic jack to the connecting square steel as the push-pull power source; S3. Cut 6.5mm thick aluminum alloy formwork, and weld square steel main ribs and U-shaped steel channel secondary ribs to the back of the formwork. Weld metal dovetail grooves along the longitudinal length of both sides of the aluminum alloy formwork where it contacts the existing concrete wall. Select a multi-chamber hollow EPDM rubber strip with an inverted trapezoidal cross-section on one side and a V-shaped unidirectional flow guide lip on the other. Slide the inverted trapezoidal side of the rubber strip into the dovetail groove and secure it. No adhesive is used during the assembly process, and the V-shaped unidirectional flow guide lip should face the concrete pouring area. S4. Using the steel plate at the end of the linkage shaft, insert it into the U-shaped steel channel secondary rib on the back of the aluminum alloy template to complete the hinge assembly. Unload the hydraulic jack, causing the drive shaft to retract, and the linkage shaft to pull the aluminum alloy templates on both sides inward to their minimum volume. At this time, the edge rubber strips are in a state of no force and inward convergence. With the help of lifting equipment and manual guidance, move and hoist the retracted inner mold support system into the narrow double-wall working space, and complete the positioning according to the positioning line. S5. Start the hydraulic pump station. The hydraulic jack pushes the transmission main shaft forward, causing axial displacement. The linkage sub-shaft converts the axial thrust into radial spreading force, pushing the aluminum alloy templates on both sides to gradually open and reach the designed angle. As the templates open, the hollow EPDM rubber strips at the edges are squeezed by the existing concrete wall surface, causing elastic deformation, filling the uneven gaps on the existing concrete wall surface, and completing the initial physical bonding. S6. After the angle is adjusted, insert the limiting pin and high-strength bolt at the intersection of the linkage sub-shaft and the main rib to form a completely rigid locking structure, and then remove the hydraulic power unit. Layered self-compacting concrete is poured into the internal space of the double walls. With the rise of the pouring liquid level and high-frequency vibration, the self-compacting concrete generates lateral pressure outwards. This lateral pressure directly compresses the inner side of the V-shaped unidirectional guide lip of the hollow EPDM rubber strip, forcing the lip to open outwards and adhere tightly to the existing concrete wall surface. The greater the lateral pressure of the concrete, the tighter the adhesion, ultimately achieving dynamic self-sealing throughout the entire pouring process. S7. After the concrete test blocks are poured and cured under the same conditions to the required compressive strength, the workers remove the limit pins and high-strength bolts. The hydraulic jacks are then reconnected and slightly pressurized to loosen the joint surfaces, followed by opening the return valve to unload the hydraulic thrust. The drive shaft retracts, causing the linkage sub-shaft to retract, and the aluminum alloy formwork on both sides to retract inwards simultaneously. The hollow EPDM rubber strips, freed from compressive force, return to their original shape and smoothly detach from the new wall and existing concrete wall surface along with the formwork. After the inner formwork support system is fully retracted, it is smoothly pulled out from one end to the other, and the surface slurry is cleaned before it can be used for the next reuse.

[0022] Operators use BIM software to input building structural drawing information and create a 3D digital model of the construction joint of the non-parallel shear wall and the surface of the existing wall. Within the 3D digital model, they measure and extract the included angle between the non-parallel double walls and the depth dimensions of the work space.

[0023] After extracting the spatial dimensions, the material physical parameters of the hollow EPDM rubber strip, including cross-sectional dimensions and elastic limit values, are input into the BIM software. The 3D model of the inner mold support system, including the transmission frame and template, is placed inside the 3D digital model of the construction joint. The hydraulic thrust stroke parameters are set, and the kinematic simulation of the system unfolding from the contracted state to the target angle is performed.

[0024] In the simulated opening step, the system calculates the compression deformation rate of the hollow EPDM rubber strip caused by the pressure from the existing wall surface. Deformation data under the conditions of maximum and minimum design angles are retrieved separately, and the compression values ​​of the hollow EPDM rubber strip are compared to see if they fall within the material's elastic recovery range.

[0025] If the compression value exceeds the elastic recovery requirement, modify the positioning parameters of the metal dovetail groove or the cross-sectional thickness of the hollow EPDM rubber strip in the BIM software, rerun the kinematic simulation until all the compression values ​​obtained from the simulation are within the elastic recovery range, and finally output the blanking and processing list of the metal components.

[0026] The operator reads the metal component cutting list, including the dimensions of round steel pipes with a diameter of 35mm-50mm and a wall thickness of 2mm-4mm (preferably 40mm in diameter and 3mm in wall thickness), round steel pipes with a diameter of 12mm-20mm (preferably 15mm in diameter), and square steel with a cross-sectional dimension of 30mm×30mm and a wall thickness of 3mm. The operator then uses a cutting device to cut the pipes and grinds the burrs at the ends of the pipes after cutting.

[0027] The hinge position is marked on the surface of the preferred 40mm diameter round steel tube that serves as the main drive shaft. A preferred 15mm diameter round steel tube is taken as the secondary linkage shaft. One end of the secondary linkage shaft is welded to the shaft connecting sleeve, and a supporting steel plate is welded to the tail end of the secondary linkage shaft. The connection is made by fitting the shaft connecting sleeve onto the hinge position on the surface of the main drive shaft, thus setting a movable hinge point. Multiple secondary linkage shafts are sequentially installed along the circumference and length of the main drive shaft to form a transmission frame.

[0028] Mark the hinge position on the surface of the round steel tube that serves as the main transmission shaft. Take a round steel tube that serves as the secondary linkage shaft and connect one end of the secondary linkage shaft to the hinge position on the surface of the main transmission shaft to set a movable hinge point. Install multiple secondary linkage shafts sequentially along the circumference and length of the main transmission shaft to form a transmission frame.

[0029] Take the cut square steel and place it at one end of the drive shaft. Adjust the position of the square steel so that its central axis is aligned with the central axis of the drive shaft. Perform spot welding pre-assembly on the contact surfaces of the square steel and the drive shaft. After verifying that the structural dimensions and linkage function are correct, perform full welding on the pre-assembled area, ensuring that the weld width is greater than or equal to 10mm and that there are no porosity or burn defects.

[0030] Place a hydraulic jack with a rated power of not less than 5KN (preferably 5KN) and a stroke greater than 100mm horizontally, aligning the output end of the push rod with the other end of the square steel. Ensure that the central axis of the connecting square steel is aligned with the central axis of the hydraulic jack. Use metal fasteners to assemble the hydraulic jack and the square steel. Connect the hydraulic pump station and input power to the hydraulic jack, observing whether the push rod can extend forward and retract backward. The push rod generates linear displacement, causing the square steel and the transmission main shaft to move synchronously. The transmission main shaft pulls the surrounding linkage sub-shafts to open or close. Inspect the operation of multiple moving hinge points. If friction or jamming occurs, grind the hinge connections until mechanical transmission is smooth, completing the processing and assembly steps.

[0031] Prepare aluminum alloy templates with a thickness of 5.0mm-8.0mm (preferably 6.5mm in this embodiment) according to the bill of materials, and cut the aluminum alloy templates to the set dimensions. Prepare square steel and U-shaped steel channels. Select square steel with a cross-sectional size of (50-70)mm×(30-50)mm and a wall thickness of 2mm-4mm (preferably 60mm×40mm and 3mm) as the main ribs and arrange them on the back of the aluminum alloy template, controlling the center-to-center distance of the main ribs to be 500mm; select U-shaped steel channels with a cross-sectional size of (40-60)mm×(2-4)mm (preferably 50mm×3mm) as the secondary ribs and arrange them vertically above the main ribs. Pre-assemble and splice the aluminum alloy templates with the main and secondary ribs and fix them by spot welding. After measuring and accepting that the distance between the main and secondary ribs meets the preset dimensions and is tightly attached to the back of the template, perform full welding on the contact parts to form the basic support panel.

[0032] Place metal dovetail grooves along the vertical edges of the left and right sides of the foundation support panel. Adjust the direction of the metal dovetail grooves so that the groove openings face outwards, and perform a full welding operation on the metal dovetail grooves and the edges of the aluminum alloy template along the longitudinal direction to fix the metal dovetail grooves to both sides of the foundation support panel along their entire length.

[0033] Obtain a customized multi-chamber hollow EPDM rubber strip. One end of the strip's cross-section has an inverted trapezoidal solid, and the other end has a V-shaped unidirectional flow guide lip. Align the inverted trapezoidal solid with the top opening of the metal dovetail groove, and apply thrust along the groove's extension direction to allow the multi-chamber hollow EPDM rubber strip to slide into the metal dovetail groove. Continuously advance the multi-chamber hollow EPDM rubber strip until it covers the entire length of the metal dovetail groove, using the spatial geometry of the inverted trapezoidal solid and the groove opening to complete the locking action.

[0034] No chemical adhesives are added during the entire assembly process. After the fitting is completed, check the orientation of the V-shaped one-way flow guide lip to ensure that the opening of the V-shaped one-way flow guide lip faces the side of the interior space to be poured concrete.

[0035] Place the assembled base support panel and transmission frame on the working surface. Move the support steel plate at the end of the linkage shaft and embed it into the U-shaped steel channel on the back of the base support panel. Insert the pin to complete the hinge operation, establishing a mechanical connection between the transmission frame and the aluminum alloy templates on both sides. After all assembly is completed and the smoothness of opening and closing is tested and found to be satisfactory, apply a protective paint to the entire surface of the inner mold support system.

[0036] After connection, operate the hydraulic pump station return valve to unload the hydraulic jack. The push rod retracts backward, causing the square steel and drive shaft to move backward synchronously. The drive shaft pulls the surrounding linkage shafts, causing the aluminum alloy templates on both sides to move towards the center. Continue the retraction action until the inner mold support system reaches its minimum volume. At this point, the multi-chamber hollow EPDM rubber strips fixed to the edge of the aluminum alloy template are not compressed by any external components and are in a stress-free inward state.

[0037] Clean the base layer of the construction joint interface, roughen the interface surface, remove any remaining concrete debris, and mark the corner positioning lines on the ground according to the layout drawings. Use lifting equipment to lift the retracted inner formwork support system, and move the lifting equipment to slide the inner formwork support system into the confined working space inside the non-parallel double walls. Vertically lower the inner formwork support system according to the corner positioning lines marked on the ground, completing the hoisting and spatial positioning.

[0038] The operator starts the hydraulic pump station to supply power to the hydraulic jack. The hydraulic jack push rod extends forward, pushing the square steel and the drive spindle forward. During operation, the hydraulic jack pushes at a constant speed.

[0039] The main drive shaft moves forward axially, pulling multiple linked secondary shafts through hinge points. Under load, these secondary shafts extend outwards, converting the axial thrust from the main drive shaft into a radial spreading force pointing outwards on both sides. This radial spreading force acts on the U-shaped steel channel secondary ribs on the back of the aluminum alloy template, pushing the two sides of the template outwards. Operators check the opening angle until the two sides of the aluminum alloy template reach the included angle value set in the design.

[0040] As the aluminum alloy formwork opens outwards, the multi-chamber hollow EPDM rubber strips fixed to the edges of the formwork move outwards and approach the existing concrete wall. Upon contact with the existing concrete wall, the multi-chamber hollow EPDM rubber strips experience unidirectional obstruction and enter a compressed state. Under this pressure, the internal structure of the multi-chamber hollow EPDM rubber strips undergoes elastic deformation. The deformed strips fill the uneven areas on the surface of the existing concrete wall, establishing a continuous, closed physical contact surface along the contour of the concrete wall.

[0041] After the aluminum alloy templates on both sides are in place, the verticality of the aluminum alloy templates is checked and verified using a laser plumb line device.

[0042] After the opening angle of the aluminum alloy templates on both sides is adjusted to the correct position and the verticality is checked to be qualified, the operator inserts a limiting pin and a high-strength bolt at the intersection of the linkage sub-shaft and the main rib. Simultaneously, a limiting device is made using plain round steel bars with a diameter of 16mm-22mm (preferably 18mm in this embodiment). One end of the limiting device is connected to the U-shaped steel channel of the secondary rib, and the other end is connected to the hydraulic jack, limiting and fixing the extension and retraction stroke of the hydraulic jack. By tightening the bolts and setting the limiting device, the supporting force maintained by the hydraulic jack is converted into a completely rigid locking structure composed of metal components. After completing the locking action, holes are drilled along the positioning lines on the outside of the aluminum alloy template, and short steel bars are inserted to complete supplementary positioning and reinforcement. The hydraulic pump station's power output is then unloaded and removed.

[0043] Subsequently, within the cavity formed inside the double walls, the surface of the aluminum alloy formwork was moistened with water, and self-compacting concrete was poured in using a layered pouring process. As the concrete level rose, high-frequency vibration was performed using a vibrator, causing the unset self-compacting concrete to generate lateral pressure on the outside of the formwork.

[0044] Lateral pressure directly compresses the inner side of the V-shaped unidirectional flow-guiding lip of the multi-chamber hollow EPDM rubber strip. Under the pressure of the self-compacting concrete, the V-shaped unidirectional flow-guiding lip opens outward and tightly presses against the existing concrete wall surface. With the increase of pouring height and the influence of vibration, the lateral pressure applied by the self-compacting concrete increases synchronously, and the compressive force pressing the V-shaped unidirectional flow-guiding lip against the existing concrete wall surface increases proportionally. The multi-chamber hollow EPDM rubber strip relies on the pressure applied by the self-compacting concrete to maintain a tight seal, blocking the outward flow path of cement slurry and completing the dynamic self-sealing operation throughout the entire pouring process.

[0045] After the compressive strength of the concrete test blocks cured under the same conditions reaches the specification requirements, the operators first remove the side formwork on both sides. Then, the limiting pins, high-strength bolts, and plain round steel bar limiting devices are removed. The hydraulic pump station's return valve is opened to unload the hydraulic thrust, causing the main drive shaft to retract, driving the linkage sub-shaft to return as well. The aluminum alloy formwork on both sides simultaneously retracts inward. The hollow EPDM rubber strips, freed from compressive pressure, return to their original shape and smoothly detach from the new wall and existing concrete wall surface along with the formwork. After the inner formwork support system is completely retracted, it is smoothly pulled out from one end to the other. The surface residual slurry is cleaned and a release agent is applied, and the formwork is ready for the next reuse.

[0046] Comparative Examples 1-3: Comparative Example 1: Compared with Example 1, the difference is that the hydraulic linkage support system for the inner mold was not used. Instead, extruded polystyrene boards were manually cut and pieced together to fill the construction joints of the non-parallel double walls, and wooden formwork was erected on the outside of the double walls for reinforcement. All other aspects are the same.

[0047] Comparative Example 2: Compared with Example 1, the difference is that instead of using a multi-chamber hollow EPDM rubber strip and a V-shaped unidirectional flow guide lip, a regular solid flat rubber strip is attached to the edge of the aluminum alloy template as a sealing material. All other aspects are the same.

[0048] Comparative Example 3: Compared with Example 1, the difference is that the rigid locking structure composed of limit pins and high-strength bolts is not used. During the concrete pouring and vibration process, the aluminum alloy formwork is kept open by relying solely on the hydraulic pump station and hydraulic jacks to maintain continuous pressure. All other aspects are the same.

[0049] Test Example 1-3: Test Example 1: The test objects were divided into two groups. The first group was the hydraulic linkage support inner mold system based on passive adaptive edge sealing technology prepared in Example 1, and the second group was the traditional working structure of Comparative Example 1, which used extruded polystyrene board for filling and sealing.

[0050] Two construction joint areas of non-parallel shear walls with the same size and environmental conditions were selected as test locations, corresponding to two different construction schemes.

[0051] According to the established plan, the inner sealing of the two construction joints and the reinforcement and support of the outer formwork were completed, and the layered pouring of self-compacting concrete was carried out at the same time.

[0052] During the concrete pouring and high-frequency vibration stages, record the grout leakage at two construction joint locations. A pre-set graduated cylinder was used to collect the leaked cement grout, and the volume of loss was accurately measured and recorded.

[0053] After the concrete has cured to the specified demolding strength, the formwork and sealing materials will be removed. Using a two-meter straightedge and feeler gauge, five test points will be randomly selected along the height of the newly poured wall to measure the flatness deviation, and a laser plumb line will be used to measure the verticality deviation.

[0054] Record the time spent on demolding and cleaning, and calculate the total time spent by construction workers from the start of removing the sealing materials inside the double walls to the completion of cleaning the residue on the concrete wall surface.

[0055] Table 1. Construction Effectiveness Test Data of Example 1 and Comparative Example 1

[0056] Figure 2 This is a comparison chart of the effectiveness of various indicators of Embodiment 1 and Comparative Example 1 of the present invention. Figure 2 (a) Showing the difference in grout leakage volume between Example 1 and Comparative Example 1 during the concrete pouring process; Figure 2 (b) Show the comparison results of the flatness deviation and verticality deviation of the concrete wall surface after casting; Figure 2(c) Showing the time difference between the two schemes in the demolding and cleaning stages. The horizontal axis corresponds to the two independent test objects, Example 1 and Comparative Example 1.

[0057] According to the data in Table 1, Example 1 demonstrated advantages in several construction indicators. In traditional methods, the extruded polystyrene board itself lacks rigidity, and manual on-site splicing makes it difficult to achieve a tight fit to the existing concrete wall. The liquid concrete under high-frequency vibration easily damages the joints, leading to local structural instability. Test records show that Comparative Example 1 had a leakage volume of 478.5 ml, exceeding the allowable limit. Example 1, using multi-chamber hollow EPDM rubber strips with unidirectional flow-guiding lips, passively expands outwards under lateral pressure from the concrete, tightly pressing against the existing concrete wall to establish a dynamic self-sealing system, controlling the leakage to a low level of 14.2 ml. The difference in sealing mechanism was also confirmed in the molding quality. The large loss of cement slurry not only caused honeycomb and pitted defects in the polystyrene board sealing area but also resulted in uneven stress on the outer wooden formwork. Ultimately, the flatness and verticality deviations of Comparative Example 1 reached 10.9 mm and 9.4 mm, respectively, leading to substandard wall molding quality in the corresponding areas. In contrast, Example 1, relying on an aluminum alloy template combined with a metal transmission frame to construct a rigid locking structure, not only has a higher overall load-bearing capacity than polystyrene board, but also effectively resists uneven lateral pressure, keeping both deviation indicators within 2.3mm. The reason why the demolding and cleaning time in Comparative Example 1 increased to 145.2 minutes is that polystyrene board debris and partially set cement slurry adhered to the narrow gap between the two walls, requiring workers to rely on hand-held iron rods for gradual cleaning, which easily damaged the surface structure of the newly poured concrete. The hydraulic umbrella-shaped linkage frame configured in Example 1 has a one-button pressure relief and retraction function; after retracting and detaching from the concrete wall, there is less residue on the metal and rubber surfaces, reducing cleaning time to 12.5 minutes. This is based on the internal mold support logic of fluid dynamics pressure adaptive fitting combined with mechanical rigidity limiting.

[0058] Test Example 2: The test subjects were divided into two groups. The first group was the inner mold system based on passive adaptive edge sealing technology prepared in Example 1, and the second group was the inner mold system using ordinary solid flat rubber strips in Comparative Example 2.

[0059] Two non-parallel existing concrete walls, each four meters high and with a fixed angle, were constructed at the experimental site to simulate a confined and narrow actual construction work environment.

[0060] The two sets of internal formwork systems were hoisted into the two non-parallel existing walls, and the hydraulic system was activated to open the aluminum alloy formwork, so that the edge rubber strips tightly pressed against the existing concrete wall surface.

[0061] Self-compacting concrete is continuously injected into the cavity formed by the two sets of internal formwork systems and the existing wall. Every time the level of the poured liquid rises by one meter, the vibrator is immediately started to carry out high-frequency vibration operation, and each vibration lasts for three minutes.

[0062] During the layered vibration operation stage, a precision measuring cup is used to collect and measure the cumulative volume of leaked cement slurry at the bottom joint of the wall.

[0063] After the concrete has hardened and reached the predetermined demolding strength, the hydraulic pump station's return valve is operated to unload all pressure. A tension sensor is connected to the top of the aluminum alloy formwork, and a crane pulls the formwork upwards at a constant speed, recording the peak pull-out resistance displayed on the instrument panel.

[0064] Table 2. Multi-height casting test data of Example 1 and Comparative Example 2

[0065] Figure 3 This is a comparison chart of the effectiveness tests of Embodiment 1 and Comparative Example 2 at different pouring heights. Figure 3 (a) Showing the trend of cumulative leakage volume change in Example 1 and Comparative Example 2 as the concrete liquid level continues to rise; Figure 3 (b) The results show the comparison of pull-out resistance required to demold under different height standards for Example 1 and Comparative Example 2 after the concrete has been poured and reached its demolding strength. The horizontal axis of both sub-graphs uniformly represents the concrete pouring height from bottom to top.

[0066] According to the data in Table 2, the multi-chamber hollow design and unidirectional flow guide lip used in Example 1 showed better sealing performance when dealing with dynamic lateral pressure. Typically, in non-parallel confined spaces, once the pouring height exceeds two meters, the self-compacting concrete, carrying the enormous kinetic energy generated by high-frequency vibration, easily breaks through the physical barrier of traditional solid rubber strips. Comparative Example 2 precisely exposed the shortcomings of traditional passive sealing methods. As the concrete level rises, ordinary solid flat rubber strips cannot convert lateral pressure into active adhesion force. The internal pressure merely causes unidirectional compression of the solid rubber, resulting in inward yielding deformation, inevitably forming a through-channel leakage. Test records show that when the pouring height reaches four meters, the leakage in Comparative Example 2 increases to 278.85 ml. In contrast, the multi-chamber hollow EPDM rubber strip used in Example 1 utilizes fluid dynamics principles. The self-compacting concrete directly compresses the V-shaped unidirectional flow guide lip, forcing the lip to open outward and adhere tightly to the existing concrete wall. The greater the pressure applied to the concrete, the stronger the compressive force between the lip and the existing concrete wall surface. Facing a four-meter pouring head, Example 1 showed a leakage of only 15.64 ml, almost completely blocked. The solid rubber strip, after being deformed under high pressure, creates severe jamming between the aluminum alloy formwork and the concrete; in Comparative Example 2, the pull-out resistance reached 31.18 kN at a height of four meters. This enormous friction not only slows down construction but also easily scrapes away the newly formed wall surface structure. In Example 1, after the hydraulic power was removed, the hollow cavity instantly deflated and shrunk, actively peeling off the contact surface, and the pull-out resistance remained consistently low at 4.83 kN. Long-term on-site observation has also fully confirmed the rationality of this structural design, transforming passive pressure bearing into active bonding using lateral pressure, effectively solving the dynamic sealing and restricted demolding problems that have plagued the inner forming of double walls for many years.

[0067] Test Example 3: The test subjects were divided into two groups. The first group was the inner mold support system with a mechanically rigid locking structure prepared in Example 1, and the second group was the inner mold support system of Comparative Example 3 that maintained the open state by hydraulic pressure alone.

[0068] Two sets of simulated existing concrete shear walls with the same tilt angle were built on the test rig. The two sets of inner formwork support systems were hoisted into place, and the hydraulic power was turned on to expand the aluminum alloy templates on both sides to the set target angle.

[0069] In Example 1, after the opening angle is reached, a limit pin and a high-strength bolt are inserted at the intersection of the linkage sub-shaft and the main rib to complete the mechanical locking. Then, the hydraulic pump station is unloaded and the power is removed. In Comparative Example 3, the mechanical locking operation is not performed, the hydraulic pump station is kept in the energized and turned-on state, and the hydraulic system is set to continuously output thrust at the rated working pressure.

[0070] A layered pouring process was used to pump self-compacting concrete into the cavity formed inside the simulated double wall, and a high-frequency vibrator was used to perform high-frequency vibration operation. The cumulative power consumption of the hydraulic pump station during the entire pouring cycle was recorded.

[0071] As the layered pouring and vibration progress to different time points, the tiny displacement of the top of the aluminum alloy templates on both sides is read in real time using pre-fixed high-precision laser displacement sensors.

[0072] After the initial setting of the concrete is completed, the power supply to the hydraulic pump station of Comparative Example 3 is cut off, and the depressurization, shrinkage, and demolding operations of the two systems are executed simultaneously.

[0073] Table 3. Dynamic load-bearing test data of the casting process in Example 1 and Comparative Example 3

[0074] Figure 4 This is a comparison chart of the load-bearing stability and energy consumption tests of Embodiment 1 and Comparative Example 3 during the dynamic casting process of the present invention. Figure 4 (a) Showing the changes in physical displacement at the ends of the aluminum alloy templates on both sides as the pouring time progresses in Example 1 and Comparative Example 3; Figure 4 (b) Demonstrates the cumulative growth trend of electrical energy consumption by the hydraulic pump station during the stage of maintaining the template open in Example 1 and Comparative Example 3. The horizontal axis of both sub-graphs uniformly represents the time for layered pouring of self-compacting concrete.

[0075] According to the data in Table 3, Example 1 demonstrates advantages in dynamic load-bearing stability and energy consumption control. Previously, in confined spaces with non-parallel double walls, the premise was that as long as the hydraulic pump station was continuously powered, it could resist the lateral pressure caused by the self-compacting concrete. The test process of Comparative Example 3 reflects the limitations of continuous pressure holding under dynamic loads. Self-compacting concrete under high-frequency vibration not only generates continuous static lateral pressure but also transmits high-frequency alternating impact loads outwards. Relying solely on the hydraulic system for pressure holding, the oil undergoes slight volume compression and backflow within the rubber hoses and piston sealing assembly. The retreat of the hydraulic fluid causes the displacement at the end of the formwork to accumulate continuously with vibration time, reaching 8.14 mm after 120 minutes of operation in Comparative Example 3. Due to the response decay of the hydraulic circuit to transient mechanical impacts, the hydraulic pump station needs to frequently start the motor to compensate for pressure loss, resulting in an increase in cumulative power consumption to 11.02 kWh within 120 minutes. Introducing a mechanical rigid limiting mechanism changes the stress state. Example 1 transforms the elastic support dependent on fluid pressure into a rigid, physically locked structure where metal components bear the load. The compressive stiffness of the square and round steel pipes counteracts the alternating impact of the fluid concrete, controlling the maximum end displacement within 0.76 mm over 120 minutes. After the insertion and tightening of the limit pins, the power to the pump station is cut off, maintaining the total energy consumption at 0.05 kWh, the same as the initial energy consumption during the opening process. Combined with previous field measurement records of similar high-pressure conditions in foundation pit support, this rigid locking not only reduces unnecessary power consumption but also eliminates the risk of sudden pipe rupture due to continuous high pressure, which could lead to the overall collapse of the formwork. It also ensures that the forming accuracy of the inner side of the double walls is within a stable and controllable physical benchmark.

Claims

1. A BIM-based method for supporting the internal formwork of construction joints in adjustable-angle shear walls, characterized in that, include: A three-dimensional digital model was constructed using BIM software, and the physical parameters of the multi-chamber hollow EPDM rubber strip were input for kinematic simulation, so that the simulated compression value was within the elastic recovery range. Assemble the main drive shaft and the secondary drive shaft, and connect them with hydraulic jacks to form a transmission frame; Square steel main ribs and U-shaped steel channel secondary ribs are welded to the back of the aluminum alloy template, and multi-chamber hollow EPDM rubber strips are assembled on both sides of the aluminum alloy template. The transmission frame and the aluminum alloy template are connected to form an inner mold support system; After the hydraulic jack retracts the inner mold support system, it is hoisted into place in the working space; The hydraulic jack pushes the transmission frame to open the aluminum alloy templates on both sides to the target angle, causing the multi-chamber hollow EPDM rubber strip to squeeze the existing concrete wall surface; A completely rigid locking structure is formed, and self-compacting concrete is poured. The lateral pressure generated by the pouring is used to compress the multi-chamber hollow EPDM rubber strip to adhere tightly to the existing concrete wall. After the self-compacting concrete reaches the required strength, the thrust of the hydraulic jack is unloaded, causing the aluminum alloy formwork to shrink, and finally the inner formwork support system is removed for demolding.

2. The method for supporting the inner formwork of construction joints in adjustable-angle shear walls based on BIM according to claim 1, characterized in that, Input the physical parameters of the multi-chamber hollow EPDM rubber strip to perform kinematic simulation, ensuring that the simulated compression value is within the elastic recovery range, including the following steps: Extract the included angle value between the non-parallel double walls from the three-dimensional digital model; In the kinematic simulation, the compression deformation rate of the multi-chamber hollow EPDM rubber strip under the pressure of the existing concrete wall is calculated as the compression value. The deformation data under the maximum and minimum design angles corresponding to the included angle value are retrieved respectively, and the compression value of the multi-chamber hollow EPDM rubber strip is compared to see if it is within the elastic recovery range of the material itself. If the compression value exceeds the elastic recovery range, the cross-sectional thickness of the multi-chamber hollow EPDM rubber strip, which is the physical parameter, is modified in the BIM software, and the kinematic simulation is performed again until the compression value obtained from the simulation is within the elastic recovery range.

3. The method for supporting the inner formwork of construction joints in adjustable-angle shear walls based on BIM according to claim 1, characterized in that, Assembling the multi-chamber hollow EPDM rubber strip includes the following specific steps: Along the longitudinal length of both sides of the aluminum alloy template in contact with the existing concrete wall, metal dovetail grooves are fully welded. A multi-chamber hollow EPDM rubber strip with an inverted trapezoidal cross-section on one side and a V-shaped unidirectional flow guide lip on the other side is selected. The inverted trapezoidal side of the multi-chamber hollow EPDM rubber strip is slid into and locked along the metal dovetail groove. No adhesive is used during the assembly process. The opening of the V-shaped unidirectional flow guide lip is kept facing the internal space where the self-compacting concrete is to be poured.

4. The method for supporting the inner formwork of construction joints in adjustable-angle shear walls based on BIM according to claim 1, characterized in that, The assembly of the transmission main shaft and the linkage secondary shaft includes the following specific steps: Mark the hinge position on the surface of the round steel tube that serves as the transmission main shaft, weld one end of the linkage secondary shaft to the shaft connecting sleeve, and weld a support steel plate to the tail of the linkage secondary shaft. The shaft connecting sleeve is used to connect the shaft at the hinge position on the surface of the transmission main shaft, and a movable hinge point is set. Multiple linkage shafts are sequentially installed along the circumferential and length directions of the transmission main shaft. Square steel is fully welded coaxially to one end of the transmission main shaft to form a radial umbrella-shaped frame. The hydraulic jack is then connected to the connecting square steel.

5. The method for supporting the internal formwork of the construction joint of an adjustable-angle shear wall based on BIM according to claim 4, characterized in that, After the hydraulic jack retracts the inner mold support system, it is hoisted into place in the working space, including the following specific steps: The supporting steel plate at the end of the linkage sub-shaft is embedded into the U-shaped steel channel secondary rib on the back of the aluminum alloy template to complete the hinge assembly; The hydraulic jack is unloaded, causing the transmission main shaft to retract. The linkage secondary shaft pulls the aluminum alloy templates on both sides to retract inward, and the retraction action continues until the inner mold support system reaches its minimum volume. Clean the base layer of the construction joint surface, roughen the construction joint surface, remove residual concrete fragments, and mark the corner positioning lines on the ground according to the layout drawings. The retracted inner mold support system is lifted using a lifting device, moved horizontally into the confined working space, and then vertically lowered according to the corner positioning line marked on the ground, thus completing the lifting and spatial positioning actions.

6. The method for supporting the inner formwork of construction joints in adjustable-angle shear walls based on BIM according to claim 4, characterized in that, The hydraulic jack pushes the transmission frame to open the aluminum alloy templates on both sides to the target angle, including the following specific steps: Power is supplied to the hydraulic jack, and the push rod of the hydraulic jack extends forward, pushing the connecting square steel and the transmission main shaft to move forward; The transmission main shaft moves forward along the axial direction, generating axial thrust, and pulls multiple linkage shafts through the movable hinge point; When the linkage shaft is subjected to force, it extends outward, converting the axial thrust into a radial spreading force pointing outward on both sides, pushing the aluminum alloy templates on both sides to open outward until the aluminum alloy templates on both sides reach the target angle. As the aluminum alloy template opens outward, the multi-chamber hollow EPDM rubber strip undergoes elastic deformation under pressure, and the deformed multi-chamber hollow EPDM rubber strip fills the uneven areas on the surface of the existing concrete wall.

7. The method for supporting the inner formwork of construction joints in adjustable-angle shear walls based on BIM according to claim 5, characterized in that, The formation of a fully rigid locking structure includes the following specific steps: After the aluminum alloy templates on both sides are stretched into place, the verticality of the aluminum alloy templates is checked and verified using a laser plumb line device. At the intersection of the linkage sub-shaft and the square steel main rib, a limiting pin and a high-strength bolt are inserted. At the same time, a limiting device is made using a plain round steel bar with a diameter of 16mm-22mm. One end of the limiting device is connected to the U-shaped steel channel secondary rib, and the other end is connected to the hydraulic jack. The extension stroke of the hydraulic jack is limited and fixed, and the spreading support force maintained by the hydraulic jack is converted into the completely rigid locking structure. After the locking action is completed, holes are drilled along the corner positioning line on the outside of the aluminum alloy template and short steel bars are inserted to complete the supplementary positioning and reinforcement.

8. The method for supporting the inner formwork of construction joints in adjustable-angle shear walls based on BIM according to claim 1, characterized in that, The pouring of the self-compacting concrete includes the following specific steps: Inside the cavity formed by the double walls, the surface of the aluminum alloy template is moistened with water, and the self-compacting concrete is poured using a layered pouring process. As the level of the poured liquid continues to rise, and with the help of a vibrator for high-frequency compaction, the un-set self-compacting concrete generates lateral pressure on the outside of the aluminum alloy formwork. The lateral pressure directly presses against the inner side of the V-shaped unidirectional flow guide lip of the multi-chamber hollow EPDM rubber strip, forcing the V-shaped unidirectional flow guide lip to open outward and tightly press against the existing concrete wall surface. As the level of the pouring liquid increases and the high-frequency vibration is applied, the lateral pressure increases synchronously, and the compressive force that compresses the V-shaped unidirectional guide lip against the existing concrete wall increases proportionally.

9. The method for supporting the inner formwork of construction joints in adjustable-angle shear walls based on BIM according to claim 7, characterized in that, Demolding the inner mold support system involves the following specific steps: After the self-compacting concrete reaches the required strength, remove the limiting pin, the high-strength bolt, and the limiting device. The hydraulic jack is reconnected and slightly pressurized to loosen the construction joint surface. Then the hydraulic thrust of the hydraulic jack is unloaded, the transmission main shaft retracts and drives the linkage secondary shaft to retract, and the aluminum alloy templates on both sides retract inward synchronously. After the inner mold support system is fully retracted, smoothly pull the inner mold support system out from one end to the other along the cavity formed inside the non-parallel double walls, clean the residual slurry on the surface of the inner mold support system and apply a release agent.

10. The method for supporting the inner formwork of construction joints in adjustable-angle shear walls based on BIM according to claim 1, characterized in that, The material parameters used in the method meet the following conditions: The transmission spindle is made of round steel pipe with a diameter of 35mm-50mm and a wall thickness of 2mm-4mm; The linkage shaft is made of round steel pipe with a diameter of 12mm-20mm; The main square steel ribs are made of square steel with a cross-sectional dimension of (50-70) mm × (30-50) mm and a wall thickness of 2 mm-4 mm; The secondary rib of the U-shaped steel channel adopts a U-shaped steel channel with a cross-sectional dimension of (40-60) mm × (2-4) mm; The rated power of the hydraulic jack is not less than 5KN and the stroke is greater than 100mm; The thickness of the aluminum alloy template is 5.0mm-8.0mm.

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