Construction method of combined support system for highway-railway combined construction continuous beam construction

Abstract

The invention provides a construction method of a combined support system for highway-railway combined construction continuous beam construction, and relates to the field of bridges, the construction method comprises the following steps: S1, foundation and support construction: completing foundation and upper and lower layer pier body construction, and installing a lower layer railway steel pipe less support and an upper layer highway full framing; and S2, upper-layer road beam construction: erecting a formwork, binding upper-layer road beam steel bars, pouring concrete, tensioning prestress, and sequentially removing upper-layer brackets to finish structural system conversion and construction of a bridge deck system and traffic safety facilities. Through the cooperation of the structures, the combined support system has the following beneficial effects that firstly, a combined support system combining a steel pipe few support and a full support can be adopted, the support does not need to be frequently replaced or adjusted, the construction time and cost are saved, the construction efficiency is greatly improved, and the construction difficulty is reduced; and secondly, in the mounting process of the bracket, the actual construction load condition of the beam body is effectively simulated through graded loading of 0.6, 0.8, 1.0 and 1.2 times of design loads.

Description

Technical Field

[0001] The invention relates to the field of bridges, and in particular to a construction method of a combined support system for construction of a highway-railway combined continuous beam. Background Art

[0002] In modern transportation construction, the joint construction of roads and railways has become an important trend. Generally, the joint construction of roads and railways is mostly double-deck bridges. Conventional construction technology often uses independent steel pipes with few supports or full supports. After the construction of the upper beams, some supports are removed and the lower beams can be constructed only after the lower supports are completed.

[0003] When building bridges using conventional techniques, there may be insufficient or excessive preloading. If the preloading load is insufficient, it will not be able to simulate the full load of the beam during actual construction, which may cause the bracket to deform too much during subsequent construction. On the contrary, excessive preloading may damage the bracket and affect its load-bearing capacity. Summary of the invention

[0004] In view of the deficiencies in the above-mentioned prior art, the technical problem to be solved by the present invention is to provide a construction method for a combined support system for the construction of continuous beams for combined highway and railway construction, which can adopt a combined support system combining a few steel pipe supports and a full-bridge support, and through simulated load grading loading, ensure the stability and safety of the support during the construction process and reduce the difficulty of construction.

[0005] In order to solve the above technical problems, the technical solution adopted by the present invention is: the present invention provides a construction method of a combined support system for the construction of a continuous beam for a highway-railway joint construction, comprising the following steps: S1. Foundation and support construction: Complete the construction of foundation and upper and lower piers, and install the lower railway steel pipe short support and upper highway full support; S2. Construction of upper highway beams: erecting formwork and tying the upper highway beam reinforcement, pouring concrete, tensioning prestressing, and dismantling the upper supports in sequence to complete the structural system conversion and the construction of the bridge deck system and traffic safety facilities; S3. Construction of lower railway beams: After the upper highway beams are inspected and accepted, the bottom formwork of the lower railway beams is installed and prestressed repeatedly. The supports are installed on the piers. The formwork is erected and the lower railway steel bars are tied. Concrete is poured and prestressed. The lower railway beam supports are removed in turn to complete the construction of the railway bridge deck system and ancillary projects.

[0006] In the preferred solution, the specific steps of step S1 are as follows: S11. Foundation and pier construction: obtain geological survey results and perform foundation construction according to the geological survey results; Among them, the foundation bearing capacity ranges from 150 to 300KPa, and the verticality deviation range of the pier body is The column height and cross-sectional dimension error range is ±20mm, and the concrete strength grade is 100%; S12, bracket installation: obtain the lower layer railway steel pipe few brackets and the upper layer highway full brackets, and determine the bracket installation data according to the lower layer railway steel pipe few brackets and the upper layer highway full brackets.

[0007] In the preferred solution, the specific steps in step S12 are as follows: S121. Installation of lower railway steel pipe brackets: Use measuring equipment to determine the position of steel pipe piles. The plane position deviation range of steel pipe piles is ±50mm; Use piling equipment to drive steel pipe piles vertically into the foundation, and the verticality deviation range of the steel pipe piles is 1%; The depth of the steel pipe pile into the soil is determined according to the geological survey report and the design load, and the depth of the pile end of the steel pipe pile into the bearing layer ranges from 3m to 7m; Real-time monitoring of the verticality and depth of the pile, with measurement performed every 2m; Confirm that the piling is completed, control the measurement error range of the top elevation of the steel pipe pile to be ±30mm, set a steel column on the top of the steel pipe pile, connect the bottom of the steel column to the top of the steel pipe pile, and the height range of the weld between the steel column and the steel pipe pile is 8mm to 16mm; Use measuring equipment to measure and adjust the position and elevation of steel columns, perform a measurement review for each installed steel column, and set diagonal braces and parallel joints on the steel columns; The parallel joints are installed at different heights of the steel columns. The horizontal deviation range of the parallel joints is ±10mm. The parallel joints are installed first, and then the diagonal braces are installed. The positions and angles of the diagonal braces and parallel joints are monitored in real time. A load-relief block is installed at the top of the steel column near the railway beam, and the installation position deviation of the load-relief block is ±10mm; After the installation of the lower-level railway steel pipe bracket is completed, a comprehensive inspection of the bracket system is carried out.

[0008] S122. Installation of upper highway full-bridge support: multiple vertical poles are arranged on the full-bridge support, and the horizontal spacing of each adjacent vertical pole perpendicular to the longitudinal direction of the bridge ranges from 0.9m to 1.5m, and the longitudinal spacing of each adjacent vertical pole along the longitudinal direction of the bridge ranges from 0.6m to 1.2m. The step distance between each two adjacent layers of horizontal poles ranges from 1.2m to 1.8m. Sweeping poles are arranged at the bottom of each vertical pole and close to the ground to form a closed bottom frame structure. The vertical poles are connected to the horizontal poles and the diagonal poles to form a triangular structure. Sealing rods are provided on the vertical poles, which connect the vertical poles at the edges to prevent the vertical poles at the ends of the bracket from opening outward or deforming.

[0009] In the preferred solution, in step S121, the verticality deviation range of the steel column is The column height, the spacing deviation between adjacent steel columns is ±20mm, the installation angle formed between the diagonal brace and the steel column is 45° to 60°, the angle error between the diagonal brace and the steel column is ±2°, and the tightening torque range between the steel column and the steel pipe pile is 400N・m to 600N・m; In step S122, the tightening torque range of the connecting fasteners of the horizontal rod is 40N·m to 70N·m, and the distance between each adjacent diagonal rod is 0.1m to 1m.

[0010] In the preferred solution, the specific steps of step S2 are as follows: S21, steel bar binding: use positioning bars and binding wire to fix the steel bars, the spacing of the positioning bars ranges from 10cm to 50cm, and the thickness of the steel bar cover ranges from 30mm to 50mm; S22. Concrete pouring: adopt layered pouring method, with each layer thickness ranging from 30cm to 50cm, and use an inserted vibrator to vibrate quickly and slowly, with the spacing between vibration points being 1 to 1.5 times the effective radius of the vibrator; The concrete pouring speed is determined based on the concrete supply capacity, formwork bearing capacity and vibration effect. The concrete pouring volume per hour is 70% to 80% of the design bearing capacity of the formwork.

[0011] Among them, the slump of monitored concrete is maintained in the range of 160mm to 200mm; S23, prestressing: when the concrete strength reaches 75% of the design strength, the prestressing operation is performed; S24, bracket removal: remove the upper full-hall brackets in sequence, the removal order is: first remove the sealing rods, then remove the diagonal rods, horizontal rods, and finally remove the vertical rods, and use lifting equipment to lift the removed parts to the designated location for storage, and set up warning signs around the removal area; S25, structural system conversion and ancillary facilities construction: after the support is dismantled, the structural system conversion is carried out; S26. Bridge inspection and operation: After the construction of the bridge deck system and traffic safety facilities is completed, the bridge inspection shall be carried out.

[0012] In a preferred solution, in step S23, the tensioning sequence and the tensioning control force F are obtained, and a sensor is installed on the tensioning device; Wherein, the sensor includes a displacement sensor and a pressure sensor; A pressure sensor with a full scale of ±1% and a displacement sensor with an accuracy of ±1mm are provided to monitor the tension force and the elongation △L of the prestressed tendon in real time; According to the elastic modulus E, cross-sectional area A and length L of the prestressed tendon, Hooke's law is used. Calculate the theoretical elongation of the prestressed tendon, compare the theoretical elongation of the prestressed tendon with the measured elongation, and the deviation range between the theoretical elongation of the prestressed tendon and the measured elongation is ±6%. If the deviation exceeds the set range, stop tensioning.

[0013] In a preferred solution, in step S25, the structural system includes casting guardrails, installing drainage pipes, expansion joints, and constructing bridge deck pavement; During the guardrail casting stage, the guardrail plane position deviation range is controlled to be ±20mm, and the elevation deviation is ±10mm; During the installation of the drain pipe, the slope of the drain pipe should be controlled within the range of 1% to 3%; Control the installation temperature range of expansion joints to be between 10°C and 25°C; During the bridge deck paving stage, the beam surface is first cleaned and roughened to ensure a tight bond between the beam and the paving layer. Among them, the bridge deck pavement thickness error is ±5mm, the flatness error range is ±3mm, and the cross slope error range is ±0.5%; Vibrating beams and flat vibrator equipment are used to carry out vibration and compaction.

[0014] In the preferred solution, the specific steps of step S3 are as follows: S31, bottom mold installation: During the installation of the bottom mold, use measuring equipment to measure and control the bottom mold elevation error to ±5mm and the flatness error to ±3mm; The bottom mold is 18mm thick, the joints are sealed to prevent leakage, and a release agent is applied to the surface of the bottom mold. S32, support preloading: perform support preloading, calculate the design load value P according to the deadweight of the beam and the construction load, and select one of the sandbags or water tanks as the preloading material, the load is graded to 0.6, 0.8, 1.0, 1.2 times, and the load holding time after each level of loading is 3 to 4 hours. During each level of loading, use sensors to monitor the support settlement and stress in real time, record the data and draw the load-settlement curve Ps curve. When the settlement of the support remains within ±2mm for 3 consecutive hours, proceed to the next level of loading; After the preloading is completed, the support elevation is adjusted according to the settlement observation data, and the elastic deformation range of the support is controlled to be 5mm to 10mm; S33, Support installation: When installing the support on the pier, the support plane position deviation range is controlled to be ±10mm, and the elevation deviation range is ±5mm; The support is connected to the pier body and beam body by bolts. The tightening torque of the bolts ranges from 300N·m to 500N·m, and anti-loosening treatment is performed.

[0015] In a preferred solution, the construction process from step S1 to step S3 also includes step S4 of using an AI model for data processing and construction control, which specifically includes the following steps: S41, data collection and preprocessing step: collecting construction data of the support preloading process, concrete pouring process and prestressing process, and performing preprocessing on the collected construction data; The preprocessed construction data is divided into 70% training set, 20% validation set, and 10% test set; S42, model selection and training step: selecting a suitable AI model based on the preprocessed construction data, including a neural network model or a support vector machine model; Using a neural network model, the number of input layer nodes is determined according to the dimensions of the input data, including the number of variables such as load, time, and temperature; The hidden layer structure is set to 2 to 3 layers, the number of nodes in each layer is set to 10 to 20, and the optimal hidden layer parameters are determined through experiments and optimization; Determine the number of output layer nodes according to the type of predicted results, including settlement prediction values ​​and stress prediction values; Use the training set data to train the selected model, use the back-propagation algorithm to dynamically adjust the model weights and biases, set a reasonable learning rate range of 0.001 to 0.01, set the number of training rounds to 100 to 500 rounds, and the batch size to 32 to 64; During the training process, the validation set is used to continuously evaluate the performance of the model. The mean square error (MSE) and mean absolute error (MAE) indicators are used to measure the deviation between the predicted value and the true value. When the validation set error no longer decreases, the training is stopped to prevent overfitting. S43, model evaluation and application step: use the test set data to perform a comprehensive evaluation on the trained model, calculate the mean square error (MSE) and mean absolute error (MAE) of various evaluation indicators, and if the model performance meets the predetermined requirements, apply the model in actual construction; During the support preloading stage, the load data collected in real time is input into the model to quickly predict the settlement value, and then compared and analyzed with the measured settlement value, and the loading strategy is adjusted in time according to the deviation; During the concrete pouring process, the model is used to predict the temperature stress change of concrete, according to the concrete temperature stress calculation formula: ; in, is the elastic modulus of concrete, is the linear expansion coefficient of concrete, is the temperature difference between the inside and outside of the concrete; Take effective temperature control measures based on the prediction results, including adjusting the curing temperature, optimizing the pouring time interval, etc.; During the prestressing stage, the model is used to predict the prestress loss, which includes the loss caused by anchor deformation and prestressing tendon shrinkage. , losses caused by friction between the prestressed tendons and the hole wall , the loss caused by the temperature difference between the prestressed tendons under tension and the equipment bearing the tension during concrete heating and curing , Losses caused by stress relaxation of prestressed tendons and losses caused by concrete shrinkage and creep ; The calculation formula for the loss caused by anchor deformation and prestressed tendon shrinkage is as follows: ; in, is the anchor deformation and prestressed tendon shrinkage value, is the effective length of the prestressed tendon; The calculation formula for the loss caused by friction between the prestressed tendons and the hole wall is as follows: ; in, To control the stress of tension, To consider the friction coefficient of local deviation per meter of the channel length, is the length of the channel from the tensioning end to the calculation section, is the friction coefficient between the prestressed tendons and the hole wall, It is the sum of the angles between the tension end and the tangent line of the calculated section curve channel part; According to the prediction results, corresponding measures are taken during the tensioning process, including increasing the tensioning control force and optimizing the anchoring process.

[0016] In the preferred solution, during the prestress loss calculation process in step S53, the above-mentioned losses are accumulated to obtain a calculation formula for the total prestress loss as follows: According to the calculation results of the total prestress loss, the prestress loss can be effectively compensated by increasing the tension control force and optimizing the anchoring system.

[0017] The present invention provides a construction method of a combined support system for the construction of a continuous beam of a road-rail joint construction. The cooperation between the above structures has the following beneficial effects: First, a combined bracket system combining steel pipe few brackets and full brackets can be used. After the upper beams are constructed, the buckle brackets can be removed to construct the lower beams. The design of the combined bracket system meets the needs of different construction stages. There is no need to frequently replace or adjust the brackets, saving construction time and cost, greatly improving construction efficiency and reducing construction difficulty. Second, during the installation of the bracket, the actual construction load of the beam was effectively simulated through graded loading of 0.6, 0.8, 1.0, and 1.2 times the design load, avoiding the problem of excessive deformation of the bracket in subsequent construction due to insufficient pre-compression, ensuring the stability and safety of the bracket during construction, and ensuring the quality of beam construction; at the same time, it also prevented excessive pre-compression from damaging the bracket and affecting the bearing capacity, thereby extending the service life of the bracket and reducing construction costs. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] The present invention will be further described below in conjunction with the accompanying drawings and embodiments: Figure 1 It is the main structural diagram of the process of the present invention; Figure 2 It is an upper elevation view of the combined support system of the present invention; Figure 3 It is a lower elevation view of the combined support system of the present invention.

[0019] In the figure: railway beam 1, highway beam 2, steel pipe pile 3, steel column 4, diagonal brace 5, flat joint 6, unloading block 7, sweeping rod 8, vertical rod 9, horizontal rod 10, diagonal rod 11, sealing rod 12. DETAILED DESCRIPTION

[0020] In order to better understand the purpose, structure and function of the present invention, the embodiments and features in the embodiments of the present application can be combined with each other without conflict. The present invention will be described in detail below with reference to the accompanying drawings and in combination with the embodiments.

[0021] Example 1 like Figures 1 to 3 As shown, this embodiment shows a construction method of a combined support system for the construction of a continuous beam for a road-rail joint construction, comprising the following steps: S1. Foundation and support construction: Complete the construction of the foundation and the upper and lower piers, and install the lower railway steel pipe support and the upper highway support. The specific steps are as follows: S11. Foundation and pier construction: obtain geological survey results and perform foundation construction according to the geological survey results; Among them, the foundation bearing capacity ranges from 150 to 300KPa, and the verticality deviation range of the pier body is The column height and cross-sectional dimension error range is ±20mm, and the concrete strength grade range is 100%; S12, bracket installation: obtain the lower layer railway steel pipe few brackets and the upper layer highway full brackets, and determine the bracket installation data according to the lower layer railway steel pipe few brackets and the upper layer highway full brackets.

[0022] S121. Installation of the lower railway steel pipe bracket: Use total station and other measuring equipment to accurately determine the position of the steel pipe pile 3, with a plane position deviation range of ±50mm.

[0023] Suitable piling equipment is used, and further, the piling equipment is a hydraulic pile driver, to vertically drive the steel pipe pile 3 into the foundation, and the verticality deviation is controlled within 1%.

[0024] The burying depth of the steel pipe pile 3 is determined according to the geological survey report and the design bearing requirements, ensuring that the pile end of the steel pipe pile 3 enters the bearing layer to a depth of 3m-7m to ensure the bearing capacity of the foundation.

[0025] During the piling process, the verticality and depth of the pile into the soil are monitored in real time, with measurements taken every 2 meters. If there is any deviation, adjustments are made in a timely manner.

[0026] After the piling is completed, the elevation of the top of the steel pipe pile is measured, and the error range is within ±30mm. The steel column 4 is installed on the top of the completed steel pipe pile 3, and the bottom of the steel column 4 is connected to the top of the steel pipe pile 3 by welding or high-strength bolts.

[0027] Before connection, ensure that the contact surface between the top of the steel pipe pile 3 and the bottom of the steel column 4 is flat and clean. The weld height range is 8mm to 16mm during welding, and the welding quality must meet the secondary weld standard; When high-strength bolts are used for connection, the tightening torque range is 400N·m to 600N·m to ensure a firm and reliable connection.

[0028] When installing the steel column 4, the verticality deviation range is The column height and the spacing deviation between adjacent steel columns 4 are ±20mm to ensure the accurate installation of subsequent diagonal braces and parallel joints.

[0029] The position and elevation of the steel column 4 are measured and adjusted using a total station and a level. After each steel column 4 is installed, a measurement review is performed, and the diagonal brace 5 and the parallel joint 6 are installed to enhance the stability of the bracket.

[0030] The diagonal brace 5 and the parallel link 6 are connected to the steel column 4 by welding or bolting.

[0031] During welding, the weld quality must meet the secondary weld standard; When bolted, the installation angle of the diagonal brace 5 is determined according to the design, and the angle between the diagonal brace 5 and the steel column 4 is 45° to 60°, and the angle error between the diagonal brace 5 and the steel column 4 is ±2°.

[0032] The tie 6 is installed at different heights of the steel column 4, and the horizontal deviation range of the tie 6 is ±10mm. The tie 6 is installed first, and then the diagonal brace 5 is installed. During the installation process, the position and angle of the diagonal brace 5 and the tie 6 are monitored in real time using measuring tools to ensure installation accuracy.

[0033] After installation, check the firmness of each connection point, and conduct visual inspection and non-destructive testing of the welds, including ultrasonic testing, to ensure there are no welding defects; Specifically, the bridge includes a railway beam 1 and a highway beam 2. The main function of the steel pipe pile 3 is to transfer various loads from the upper structure to the deep ground. In the construction of the railway-highway bridge, it bears the weight from the railway beam 1 and the highway beam 2 brackets, and is used to resist vertical loads and horizontal loads, and prevent horizontal displacement of the brackets and beams; The steel column 4 plays a connecting role in the support structure. It transfers the load of the railway beam 1, the highway beam 2 and the support to the steel pipe pile 3 below. The steel column 4 cooperates with the diagonal brace 5 and the horizontal link 6 to form a stable spatial structure. As the main vertical component, it forms a frame system together with the horizontal rod 10 in the horizontal direction, so that the support can withstand loads from all directions. Under the action of load, the steel column 4 transfers the vertical force to the foundation, and at the same time, through the connection with other components, it disperses the horizontal force to the entire support structure to ensure the overall stability of the support; When the support is subjected to horizontal loads, such as wind loads, horizontal braking forces of vehicles and trains, the diagonal brace can convert the horizontal force into axial pressure or tension, effectively resisting the lateral deformation of the support and preventing the support from tipping over or becoming unstable. During the construction of the beam, when one side is subjected to a large load, such as uneven concrete pouring, the diagonal brace can transfer this part of the load to other parts to avoid damage to local components due to excessive force. The flat joint 6 is mainly used to connect adjacent steel columns or other vertical components so that they can work together in the horizontal direction. During the bridge construction process, the flat joint 6 can evenly distribute the horizontal force to each vertical component to prevent individual components from being deformed or damaged due to excessive horizontal force. Perform torque check on the bolt connection to ensure that the bolt tightening torque meets the requirements. Install the unloading block 7 at the top of the steel column 4 near the railway beam 1. The installation position of the unloading block 7 needs to be accurately measured and positioned. The installation position deviation of the unloading block 7 is ±10mm.

[0034] The contact surfaces of the unloading block 7, the steel column 4 and the railway beam 1 need to be flat and in contact with each other, and are fixed by welding or bolting.

[0035] Furthermore, the unloading block 7 can adjust the contact state between the beam and the bracket. It can compensate for the unevenness between the bottom surface of the beam and the top of the bracket, so that the load of the beam is more evenly transferred to the bracket. At the same time, when removing the bracket, the unloading block 7 can gradually release the pressure of the beam on the bracket to achieve a safe and smooth unloading process, avoiding damage to the beam and the bracket caused by sudden unloading; During welding, the weld height and length meet the design requirements, and the welding quality complies with relevant standards; during bolt connection, the tightening torque of the bolts ranges from 200N·m to 300N·m.

[0036] The material of the unloading block 7 is selected from materials with sufficient strength and elasticity according to the design, including rubber alloy materials. After installation, check the installation firmness of the unloading block 7 and the fit with the contact surface to ensure that the unloading block can effectively buffer and transfer the load; After the installation of the lower-level railway steel pipe bracket is completed, a comprehensive inspection of the entire bracket system is carried out. The inspection content includes the installation position, verticality, horizontality, connection firmness and installation of the unloading block of each component. Use total station, level and other measuring tools to measure and verify the overall size and elevation of the bracket, compare with the design drawings, and make timely adjustments if there are deviations. Recheck the welds and bolt connections of each connection point to ensure that there are no looseness and defects. Check the installation angle and connection of the diagonal brace 5 and the parallel link 6 to ensure the stability of the bracket. During the inspection process, record the problems found in detail, formulate corrective measures, and make corrections in a timely manner to ensure that the bracket meets the design and construction requirements; S122. Installation of upper highway full-bridge support: The horizontal spacing of each adjacent vertical pole 9 in the full-bridge support perpendicular to the longitudinal direction of the bridge ranges from 0.9m to 1.5m, the longitudinal spacing of each adjacent vertical pole 9 in the full-bridge support along the longitudinal direction of the bridge ranges from 0.6m to 1.2m, and the step distance between each two adjacent horizontal poles 10 ranges from 1.2m to 1.8m. Sweeping poles 8 are set at the bottom of each vertical pole 9 and close to the ground to ensure close contact with the load-bearing platform and uniform force, forming a closed bottom frame structure. The horizontal pole 10 and the diagonal pole 11 are firmly connected to the vertical pole 9 to form a stable triangular structure. The tightening torque of the connecting fastener of the horizontal pole 10 ranges from 40N·m to 70N·m, and the spacing of each adjacent diagonal pole 11 ranges from 0.1m to 1m. The existence of the diagonal pole 11 can adjust the internal force distribution and force transmission path inside the support structure. When the bracket is subjected to load, the diagonal rod can change the direction of force transmission, dispersing the load concentrated on certain components to other components, making the force of the entire bracket structure more uniform and reasonable; Specifically, during the construction process, the sweeping rod 8 can prevent the bottom of the vertical pole 9 from being displaced, especially when subjected to horizontal forces such as wind blowing, collision with construction equipment, etc., the sweeping rod 8 can limit the horizontal movement of the vertical pole 9. At the same time, the sweeping rod 8 can transmit the horizontal force and evenly distribute it to each vertical pole 9. When the bracket is subjected to horizontal loads, the sweeping rod 8 acts as a horizontal force transmission member, transmitting the horizontal force from the load-bearing area to the adjacent vertical pole 9, so that all vertical poles 9 can resist the horizontal force together; The horizontal rod 10 is mainly used to connect adjacent vertical rods 9 to form a stable support structure in the horizontal direction, which can ensure the stability of the vertical rods in the horizontal direction and prevent the vertical rods from tilting or becoming unstable due to the action of horizontal forces. In the full-bridge support for the construction of a highway-railway combined bridge, the horizontal rod 10 connects the vertical rods 9 into a whole, working together to resist the horizontal loads from the beam body and the external environment. The horizontal rod 10 plays a role in distributing and transferring loads in the support structure. When the beam body load is transferred to the support system through the vertical rods 9, the horizontal rod 10 can distribute the vertical load between adjacent vertical rods 9, so that the load borne by each vertical rod is more uniform and reasonable. At the same time, the horizontal rod 10 can also transfer horizontal loads, including the braking force and wind load of vehicles and trains, and transfer these loads to the entire support system, which are resisted by each component together; Among them, the vertical pole 9 is the main vertical force-bearing member of the full-bridge support, which is used to directly bear the vertical load from the railway beam 1 and the highway beam 2; Specifically, in a full-chamber bracket, the sealing rod 12 connects the edge vertical rods 9 to prevent the vertical rods 9 at the ends of the bracket from opening outward or deforming, thereby ensuring the integrity and stability of the bracket structure, and is mainly used to close the ends of the bracket.

[0037] S2. Construction of upper highway beams: erect formwork and tie up the upper highway beam reinforcement, pour concrete, tension the prestress, and remove the upper supports in sequence to complete the structural system conversion and the construction of the bridge deck system and traffic safety facilities. The specific steps are as follows: S21. Rebar binding: Based on the design drawings, accurately control the type, specification, quantity and position of the steel bars. Use positioning bars and binding wires to firmly fix the steel bars. The spacing of the positioning bars ranges from 10cm to 50cm. The tightening method and degree of the binding wires should ensure that the steel bars do not move during the concrete pouring process.

[0038] Ensure that the thickness of the steel bar protection layer is in the range of 30mm to 50mm. Plastic pads or steel bar protection layer positioning pieces can be used for control. The spacing between pads or positioning pieces is in the range of 0.1m to 1m.

[0039] S22. Concrete pouring: Use layered pouring method, with each layer thickness ranging from 30cm to 50cm. Use an inserted vibrator to vibrate quickly and slowly. The spacing between vibration points is 1 to 1.5 times the radius of the vibrator. During the pouring process, control the pouring speed of concrete, which is determined according to the concrete supply capacity, the bearing capacity of the formwork and the vibration effect. The hourly pouring volume is 70% to 80% of the design bearing capacity of the formwork.

[0040] At the same time, monitor the slump of concrete, which should be kept in the range of 160mm to 200mm to ensure the workability and compactness of the concrete. During the pouring process, be careful to avoid the vibrator touching the steel bars and formwork to prevent the steel bars from shifting and the formwork from deforming.

[0041] S23, prestressing: when the concrete strength reaches 75% of the design strength, the prestressing operation is performed. The prestressing sequence and prestressing control force F specified in the design are followed, and sensors are installed on the prestressing equipment, wherein the sensors include displacement sensors and pressure sensors; A pressure sensor with a full range of ±1% and a displacement sensor with an accuracy of ±1mm are set to monitor the tension force and the elongation of the prestressed tendon △L in real time. According to the elastic modulus E, cross-sectional area A and length L of the prestressed tendon, using Hooke's law Calculate the theoretical elongation and compare it with the measured elongation. The deviation should be controlled within ±6%. If the deviation exceeds the range, the tensioning should be stopped, the cause should be analyzed and corresponding measures should be taken to adjust.

[0042] During the tensioning process, the dual control method (i.e. tensioning force and elongation control) is adopted to ensure accurate application of prestress.

[0043] S24. Removal of brackets: When removing the upper full-hall brackets, follow the principle of assembling first and dismantling later, or dismantling later and remove each component in turn.

[0044] The dismantling sequence is: first dismantle the sealing rod 12, then dismantle the diagonal rod 11, the horizontal rod 10, and finally dismantle the vertical rod 9. During the dismantling process, a crane or other suitable lifting equipment is used to lift the dismantled parts to a designated location for storage.

[0045] Demolition workers must wear safety belts and operate in a safe area. Throwing poles is strictly prohibited. At the same time, warning signs are set up around the demolition area to prevent unauthorized personnel from entering.

[0046] S25. Structural system conversion and ancillary facilities construction: After the support is removed, the structural system conversion is carried out.

[0047] Among them, the structural system includes casting guardrails, installing drainage pipes, expansion joints and constructing bridge deck pavement; When pouring the guardrail, ensure that the guardrail is positioned accurately, with a plane position deviation range of ±20mm and an elevation deviation of ±10mm. The concrete strength grade of the guardrail meets the design requirements, and the appearance quality should be flat and smooth, without defects such as cracks, honeycombs, and pockmarks.

[0048] When installing the drain pipe, ensure that the slope of the drain pipe is in the range of 1% to 3% and the joints are tight to prevent water leakage.

[0049] The installation temperature range of the expansion joint is 10℃ to 25℃, ensuring that the expansion joint has normal expansion and contraction function and that the connection with the beam is firm and reliable.

[0050] When constructing the bridge deck pavement, the surface of the beam should be cleaned and roughened first to ensure a close bond between the beam and the pavement layer.

[0051] The thickness, flatness and cross slope of the bridge deck pavement layer should meet the design requirements. The thickness error of the bridge deck pavement layer is ±5mm, the flatness error range is ±3mm, and the cross slope error range is ±0.5%.

[0052] Use vibrating beams, flat vibrators and other equipment to vibrate and compact to ensure the density of the pavement layer.

[0053] S26. Bridge inspection and operation: After the construction of the bridge deck system and traffic safety facilities is completed, the bridge inspection is carried out. The inspection content includes the concrete strength, appearance quality, structural dimensions, prestressing effect, bridge bearing capacity, linear shape and other aspects of the beam body. The concrete strength is tested by rebound method, ultrasonic-rebound comprehensive method, etc., and the estimated strength value must meet the design strength grade requirements; through appearance inspection, ensure that the beam body has no cracks, deformation and other defects; use total station, level and other measuring instruments to detect the linear shape of the bridge, and its elevation deviation and plane position deviation should be within the design allowable range. It can only be put into operation after passing the inspection. During the operation process, the bridge is regularly monitored and maintained, and the monitoring content includes structural deformation, crack development, support status, etc. to ensure the safe use of the bridge.

[0054] S3. Construction of lower railway beams: After the upper highway beams are inspected and accepted, the bottom formwork of the lower railway beams is installed and prestressed repeatedly, the supports are installed on the piers, the formwork is erected to tie the lower railway steel bars, concrete is poured, prestressing is applied, and the lower railway beam supports are removed in sequence to complete the construction of the railway bridge deck system and ancillary projects. The specific steps are as follows: S31. Installation of bottom mold: When installing the bottom mold, use a total station and a level to perform precise measurements, and control the bottom mold elevation within an error of ±5mm, and the flatness error within ±3mm; The bottom mold uses a high-quality template with a thickness of 18mm, and the joints are sealed with sealing strips or welding to ensure that the joints are tight and prevent leakage. At the same time, a release agent is applied to the surface of the bottom mold to ensure the surface quality of the concrete; S32, support preloading: Then perform support preloading, calculate the design load value P according to the deadweight of the beam and the construction load, and select one of the sandbags or water tanks as the preloading material, the load level loading is 0.6, 0.8, 1.0, 1.2 times, and the load holding time range after each level of loading is 3 hours to 4 hours. During each level of loading, use sensors to monitor the support settlement and stress in real time, record data and draw the load-settlement curve Ps curve. When the support settlement is maintained within the range of ±2mm for 3 consecutive hours, the next level of loading is carried out. After the preloading is completed, adjust the support elevation according to the settlement observation data so that the beam bottom template meets the design elevation requirements, and the elastic deformation range of the support is 5mm to 10mm.

[0055] S33. Support installation: When installing the support on the pier, ensure that the position of the support is accurate, the plane position deviation range of the support is ±10mm, and the elevation deviation range is ±5mm.

[0056] The connection between the support and the pier body and beam body is firm and reliable. When high-strength bolts are used for connection, the tightening torque range of the bolts is 300N·m to 500N·m, and anti-loosening treatment is carried out.

[0057] S34. Rebar binding: When setting up the formwork and binding the lower layer of railway reinforcement, the reinforcement shall be HRB400 or above in accordance with the railway engineering design standards.

[0058] Use positioning bars and tying wires to firmly fix the steel bars. The spacing of the positioning bars ranges from 40cm to 50cm. The tightening method and degree of the tying wires should ensure that the steel bars do not move during the concrete pouring process. Ensure that the thickness of the steel bar cover ranges from 30mm to 50mm. Concrete pads or steel bar cover positioning pieces can be used for control. The spacing of pads or positioning pieces ranges from 0.1m to 1m.

[0059] S35, Concrete pouring: The concrete strength grade is C50, and appropriate pouring technology and vibration method are used. Before pouring, the raw materials are inspected to ensure that cement, aggregates, admixtures, etc. meet the design and specification requirements. The layered pouring method is adopted, and the thickness of each layer ranges from 30cm to 40cm. The inserted vibrator is used for fast insertion and slow withdrawal, and the spacing between vibration points ranges from 1 to 1.5 times the effective radius of the vibrator.

[0060] During the pouring process, the pouring speed of concrete is controlled and determined according to the concrete supply capacity, formwork bearing capacity and vibration effect. The hourly pouring volume ranges from 60% to 70% of the design bearing capacity of the formwork.

[0061] At the same time, monitor the slump of concrete and keep the slump of concrete in the range of 140mm to 180mm to ensure the workability and compactness of concrete. During the pouring process, be careful to avoid the vibrator touching the steel bars and formwork to prevent the steel bars from shifting and the formwork from deforming.

[0062] S36, Prestressing: When the concrete strength reaches 80% of the design strength, the prestressing operation is carried out. Strictly follow the tensioning sequence designed for railway engineering and more stringent tensioning control force and elongation control standards. Install a pressure sensor with an accuracy range of ±1% of the full scale and a displacement sensor with an accuracy range of ±1mm on the tensioning equipment to monitor the tensioning force and prestressing tendon elongation in real time. According to the elastic modulus of the prestressed tendons , cross-sectional area and length , using Hooke's law The theoretical elongation is calculated and compared with the measured elongation within a tolerance of ±5%.

[0063] If the deviation exceeds the range, stop tensioning, analyze the cause and take corresponding measures to adjust. During the tensioning process, the double control method (i.e. tensioning force and elongation control) is adopted to ensure accurate prestressing.

[0064] S37. Support removal: Remove the lower railway beam supports in accordance with the principle of erecting first and dismantling later, or erecting later and dismantling first.

[0065] The dismantling sequence is: first remove the adjustable top support, then remove the diagonal rod (11), the horizontal rod (10), and finally remove the vertical rod (9).

[0066] During the demolition process, cranes or other suitable lifting equipment are used to lift the demolished parts to the designated location for storage. Demolition workers must wear safety belts and operate in a safe area. Throwing rods is strictly prohibited. At the same time, warning signs are set up around the demolition area to prevent unauthorized personnel from entering.

[0067] S38. Construction of railway bridge deck system and ancillary works: When constructing railway bridge deck system and ancillary works, ensure that the track laying accuracy meets the requirements of railway specifications, the track gauge error range is ±6mm, the track elevation deviation range is ±10mm, and the track flatness error range is ±3mm.

[0068] The installation of auxiliary facilities such as cable troughs and sound barriers should be firm and reliable, with accurate positions to meet the functional and safety requirements of railway operations. During the construction process, strengthen quality control and safety management to ensure construction quality and safety.

[0069] The construction process from step S1 to step S3 also includes step S4, which uses an AI model to perform data processing and construction control, and specifically includes the following steps: S41, data collection and preprocessing steps: During the entire construction process, the load, settlement, and time data of the support prestressing link, the temperature, stress, and strain data of the concrete pouring process, and the tension force, elongation, time and other data of the prestressing process are comprehensively collected; the collected data are strictly screened to remove obvious outliers and erroneous data, and the moving average method or Savitzky-Golay filtering method and other data processing techniques are used to eliminate noise interference; the processed data are scientifically divided into 70% for training set, 20% for validation set, and 10% for test set, in preparation for subsequent model training and verification.

[0070] S42, model selection and training steps: According to the characteristics of the construction data and the prediction objectives, select a suitable AI model, such as a neural network model or a support vector machine model.

[0071] For the neural network model, the number of input layer nodes is determined according to the dimension of the input data, such as the number of variables such as load, time, and temperature; The hidden layer structure is set to 2 to 3 layers, the number of nodes in each layer is set to 10 to 20, and the optimal hidden layer parameters are determined through experiments and optimization; Determine the number of output layer nodes according to the type of predicted results, including settlement prediction values ​​and stress prediction values; Use the training set data to train the selected model, use the back propagation algorithm to dynamically adjust the model weights and biases, set a reasonable learning rate range of 0.001 to 0.01, set the number of training rounds to 100 to 500 rounds, and set the batch size to 32. Between 64; During the training process, the validation set is used to continuously evaluate the performance of the model. Indicators such as mean square error (MSE) and mean absolute error (MAE) are used to measure the deviation between the predicted value and the true value. When the validation set error no longer decreases, training is stopped to prevent overfitting. S43, model evaluation and application steps: Use the test set data to comprehensively evaluate the trained model, calculate the mean square error (MSE) and mean absolute error (MAE) of each evaluation indicator, and if the model performance meets the predetermined requirements, apply the model in actual construction.

[0072] During the support preloading stage, the real-time collected load data is input into the model to quickly predict the settlement value, and compared and analyzed with the measured settlement value, and the subsequent loading strategy is adjusted in time according to the deviation; During the concrete pouring process, the model is used to predict the temperature stress change of concrete, according to the concrete temperature stress calculation formula: ; in, is the elastic modulus of concrete, is the linear expansion coefficient of concrete, The temperature difference between the inside and outside of the concrete needs to be determined based on factors such as the concrete mix ratio, pouring time, and ambient temperature in actual calculations. and The value of can be reduced by controlling the concrete pouring temperature and adopting thermal insulation and maintenance measures. , thereby reducing temperature stress and preventing concrete cracks.

[0073] Take effective temperature control measures based on the prediction results, including adjusting the curing temperature, optimizing the pouring time interval, etc.; During the prestressing stage, the model is used to predict the prestress loss, which includes the loss caused by anchor deformation and prestressing tendon shrinkage. , losses caused by friction between the prestressed tendons and the hole wall , the loss caused by the temperature difference between the prestressed tendons under tension and the equipment bearing the tension during concrete heating and curing , Losses caused by stress relaxation of prestressed tendons and losses caused by concrete shrinkage and creep ; The calculation formula for the loss caused by anchor deformation and prestressed tendon shrinkage is as follows: ; in, is the anchor deformation and prestressed tendon shrinkage value, is the effective length of the prestressed tendon; The calculation formula for the loss caused by friction between the prestressed tendons and the hole wall is as follows: ; in, To control the stress of tension, To consider the friction coefficient of local deviation per meter of the channel length, is the length of the channel from the tensioning end to the calculation section, is the friction coefficient between the prestressed tendons and the hole wall, It is the sum of the angles between the tension end and the tangent line of the calculated section curve channel part; According to the prediction results, corresponding measures are taken during the tensioning process, including increasing the tensioning control force, optimizing the anchoring process, etc., to ensure that the prestressing of the beam meets the design requirements, effectively improve the crack resistance and bearing capacity of the beam, and ensure construction quality and safety.

[0074] In the prestress loss calculation process of step S53, in addition to calculating the loss caused by anchor deformation and prestressed tendon shrinkage according to the above formula, , losses caused by friction between the prestressed tendons and the hole wall In addition, the loss caused by the temperature difference between the prestressed tendons and the equipment bearing the tension during concrete heating and curing , Losses caused by stress relaxation of prestressed tendons and losses caused by concrete shrinkage and creep , and should also be accurately calculated according to the methods specified in relevant industry standards and design specifications. In actual engineering, the above losses are accumulated to obtain the calculation formula for the total prestress loss as follows: During the tensioning process, according to the calculation results of the total prestress loss, the prestress loss is effectively compensated by accurately increasing the tensioning control force, optimizing the anchoring system, etc., to ensure that the prestress of the beam meets the design requirements throughout its service life, significantly improve the structural stability, crack resistance and bearing capacity of the beam, and ensure the safe operation of the bridge.

[0075] In order to make the technical personnel in the technical field better understand the scheme of the present invention, the above-mentioned embodiments are only the preferred technical schemes of the present invention and should not be regarded as limitations of the present invention. The protection scope of the present invention should be the technical schemes recorded in the claims, including the equivalent replacement schemes of the technical features in the technical schemes recorded in the claims. That is, equivalent replacement improvements within this scope are also within the protection scope of the present invention.

[0076] It should also be noted that the terms "first", "second", etc. in the specification and claims of the present invention and the above-mentioned drawings are used to distinguish similar objects, and are not necessarily used to describe a specific order or sequence. It should be understood that the numbers used in this way can be interchanged where appropriate, so as to describe the embodiments of the present invention described herein.

Claims

1. A construction method for a combined support system for the construction of a continuous beam for a road-rail joint construction, characterized in that: The following steps are involved: S1. Foundation and support construction: Complete the construction of foundation and upper and lower piers, and install the lower railway steel pipe short support and upper highway full support; S2. Construction of upper highway beams: erecting formwork and tying the upper highway beam reinforcement, pouring concrete, tensioning prestressing, and dismantling the upper supports in sequence to complete the structural system conversion and the construction of the bridge deck system and traffic safety facilities; S3. Construction of lower railway beams: After the upper highway beams are inspected and accepted, the bottom formwork of the lower railway beams is installed and prestressed repeatedly. The supports are installed on the piers. The formwork is erected and the lower railway steel bars are tied. Concrete is poured and prestressed. The lower railway beam supports are removed in turn to complete the construction of the railway bridge deck system and ancillary projects.

2. The construction method of the combined support system for the construction of the continuous beam for the combined highway and railway construction according to claim 1 is characterized in that: The specific steps of step S1 are as follows: S11. Foundation and pier construction: obtain geological survey results and perform foundation construction according to the geological survey results; Among them, the foundation bearing capacity ranges from 150 to 300KPa, and the verticality deviation range of the pier body is The column height and cross-sectional dimension error range is ±20mm, and the concrete strength grade is 100%; S12, bracket installation: obtain the lower layer railway steel pipe few brackets and the upper layer highway full brackets, and determine the bracket installation data according to the lower layer railway steel pipe few brackets and the upper layer highway full brackets.

3. The construction method of the combined support system for the construction of the continuous beam for the combined highway and railway construction according to claim 2 is characterized in that: In step S12, the specific steps are as follows: S121, installation of the lower railway steel pipe bracket: using a measuring device to determine the position of the steel pipe pile (3), the plane position deviation range of the steel pipe pile (3) is ±50mm; Using a pile driving device, the steel pipe pile (3) is driven vertically into the foundation, and the verticality deviation range of the steel pipe pile (3) is 1%; The depth of the steel pipe pile (3) into the soil is determined according to the geological survey report and the design load, and the depth of the pile end of the steel pipe pile (3) into the bearing layer ranges from 3m to 7m; Real-time monitoring of the verticality and depth of the pile, with measurement performed every 2m; Determine that the piling is completed, control the measurement error range of the top elevation of the steel pipe pile (3) to be ±30 mm, set a steel column (4) on the top of the steel pipe pile (3), the bottom of the steel column (4) is connected to the top of the steel pipe pile (3), and the height range of the weld between the steel column (4) and the steel pipe pile (3) is 8 mm to 16 mm; Using measuring equipment to measure and adjust the position and elevation of the steel column (4), performing a measurement check once for each installed steel column (4), and respectively setting a diagonal brace (5) and a parallel joint (6) on the steel column (4); The parallel joint (6) is installed at different heights of the steel column (4), and the horizontality deviation range of the parallel joint (6) is ±10 mm. The parallel joint (6) is installed first, and then the diagonal brace (5) is installed, and the position and angle of the diagonal brace (5) and the parallel joint (6) are monitored in real time; A load-relief block (7) is provided at a position near the railway beam (1) on the top of the steel column (4), and the installation position deviation of the load-relief block (7) is ±10 mm; After the installation of the lower-level railway steel pipe bracket is completed, a comprehensive inspection of the bracket system is carried out. S122, installation of the upper highway full-bridge support: a plurality of vertical poles (9) are provided on the full-bridge support, the lateral spacing between each adjacent vertical pole (9) perpendicular to the longitudinal direction of the bridge is in the range of 0.9m to 1.5m, the longitudinal spacing between each adjacent vertical pole (9) along the longitudinal direction of the bridge is in the range of 0.6m to 1.2m, the step distance between each two adjacent layers of horizontal poles (10) is in the range of 1.2m to 1.8m, a sweeping pole (8) is provided at the bottom of each vertical pole (9) and close to the ground to form a closed bottom frame structure, the vertical poles (9) are connected to the horizontal poles (10) and the diagonal poles (11) to form a triangular structure; A sealing rod (12) is provided on the vertical rod (9), and the sealing rod (12) connects the vertical rods (9) at the edges to prevent the vertical rods (9) at the ends of the bracket from opening outwards or deforming.

4. The construction method of the combined support system for the construction of the continuous beam for the combined highway and railway construction according to claim 3 is characterized in that: In step S121, the verticality deviation range of the steel column (4) is The column height, the spacing deviation between adjacent steel columns (4) is ±20 mm, the installation angle formed between the diagonal brace (5) and the steel column (4) is 45° to 60°, the angle error between the diagonal brace (5) and the steel column (4) is ±2°, and the tightening torque range of the steel column (4) and the steel pipe pile (3) is 400 N·m to 600 N·m; In step S122, the tightening torque range of the connecting fasteners of the horizontal rod (10) is 40N·m to 70N·m, and the distance between each adjacent diagonal rod (11) is 0.1m to 1m.

5. The construction method of the combined support system for the construction of continuous beams for combined highway and railway construction according to claim 3 is characterized in that: The specific steps of step S2 are as follows: S21, steel bar binding: use positioning bars and binding wire to fix the steel bars, the spacing of the positioning bars ranges from 10cm to 50cm, and the thickness of the steel bar cover ranges from 30mm to 50mm; S22. Concrete pouring: adopt layered pouring method, with each layer thickness ranging from 30cm to 50cm, and use an inserted vibrator to vibrate quickly and slowly, with the spacing between vibration points being 1 to 1.5 times the effective radius of the vibrator; The concrete pouring speed is determined based on the concrete supply capacity, formwork bearing capacity and vibration effect. The hourly pouring volume is 70% to 80% of the design bearing capacity of the formwork. Among them, the slump of monitored concrete is maintained in the range of 160mm to 200mm; S23, prestressing: when the concrete strength reaches 75% of the design strength, the prestressing operation is performed; S24, bracket removal: remove the upper full-hall bracket in sequence, and the removal order is: first remove the sealing rod (12), then remove the diagonal rod (11), the horizontal rod (10), and finally remove the vertical rod (9), and use lifting equipment to lift the removed parts to a designated location for storage, and set up warning signs around the removal area; S25, structural system conversion and ancillary facilities construction: after the support is dismantled, the structural system conversion is carried out; S26. Bridge inspection and operation: After the construction of the bridge deck system and traffic safety facilities is completed, the bridge inspection shall be carried out.

6. The construction method of the combined support system for the construction of the continuous beam for the combined highway and railway construction according to claim 5 is characterized in that: In step S23, the tensioning sequence and the tensioning control force F are obtained, and sensors are installed on the tensioning equipment; Wherein, the sensor includes a displacement sensor and a pressure sensor; A pressure sensor with a full scale of ±1% and a displacement sensor with an accuracy of ±1mm are provided to monitor the tension force and the elongation △L of the prestressed tendon in real time; According to the elastic modulus E, cross-sectional area A and length L of the prestressed tendon, Hooke's law is used. Calculate the theoretical elongation of the prestressed tendon, compare the theoretical elongation of the prestressed tendon with the measured elongation, and the deviation range between the theoretical elongation of the prestressed tendon and the measured elongation is ±6%. If the deviation exceeds the set range, stop tensioning.

7. The construction method of the combined support system for the construction of the continuous beam for the combined highway and railway construction according to claim 6 is characterized in that: In step S25, the structural system includes casting guardrails, installing drainage pipes, expansion joints, and constructing bridge deck pavement; During the guardrail casting stage, the guardrail plane position deviation range is controlled to be ±20mm, and the elevation deviation is ±10mm; During the installation of the drain pipe, the slope of the drain pipe should be controlled within the range of 1% to 3%; Control the installation temperature range of expansion joints to be between 10°C and 25°C; During the bridge deck paving stage, the beam surface is first cleaned and roughened to ensure a tight bond between the beam and the paving layer. Among them, the bridge deck pavement thickness error is ±5mm, the flatness error range is ±3mm, and the cross slope error range is ±0.5%; Vibrating beams and flat vibrator equipment are used to carry out vibration and compaction.

8. The construction method of the combined support system for the construction of the continuous beam for the combined highway and railway construction according to claim 7 is characterized in that: The specific steps of step S3 are as follows: S31, bottom mold installation: During the installation of the bottom mold, use measuring equipment to measure and control the bottom mold elevation error to ±5mm and the flatness error to ±3mm; The bottom mold is 18mm thick, the joints are sealed to prevent leakage, and a release agent is applied to the surface of the bottom mold. S32, support preloading: perform support preloading, calculate the design load value P according to the deadweight of the beam and the construction load, and select one of the sandbags or water tanks as the preloading material, the load is graded to 0.6, 0.8, 1.0, 1.2 times, and the load holding time after each level of loading is 3 to 4 hours. During each level of loading, use sensors to monitor the support settlement and stress in real time, record the data and draw the load-settlement curve Ps curve. When the settlement of the support remains within ±2mm for 3 consecutive hours, proceed to the next level of loading; After the preloading is completed, the support elevation is adjusted according to the settlement observation data, and the elastic deformation range of the support is controlled to be 5mm to 10mm; S33, Support installation: When installing the support on the pier, the support plane position deviation range is controlled to be ±10mm, and the elevation deviation range is ±5mm; The support is connected to the pier body and beam body by bolts. The tightening torque of the bolts ranges from 300N·m to 500N·m, and anti-loosening treatment is performed.

9. The construction method of the combined support system for the construction of the continuous beam for the combined highway and railway construction according to claim 8 is characterized in that: The construction process from step S1 to step S3 also includes step S4, which uses an AI model to perform data processing and construction control, and specifically includes the following steps: S41, data collection and preprocessing step: collecting construction data of the support preloading process, concrete pouring process and prestressing process, and performing preprocessing on the collected construction data; The preprocessed construction data is divided into 70% training set, 20% validation set, and 10% test set; S42, model selection and training step: selecting a suitable AI model based on the preprocessed construction data, including a neural network model or a support vector machine model; Using a neural network model, the number of input layer nodes is determined according to the dimensions of the input data, including the number of variables such as load, time, and temperature; The hidden layer structure is set to 2 to 3 layers, the number of nodes in each layer is set to 10 to 20, and the optimal hidden layer parameters are determined through experiments and optimization; Determine the number of output layer nodes according to the type of predicted results, including settlement prediction values ​​and stress prediction values; Use the training set data to train the selected model, use the back-propagation algorithm to dynamically adjust the model weights and biases, set a reasonable learning rate range of 0.001 to 0.01, set the number of training rounds to 100 to 500 rounds, and the batch size to 32 to 64; During the training process, the validation set is used to continuously evaluate the performance of the model. The mean square error (MSE) and mean absolute error (MAE) indicators are used to measure the deviation between the predicted value and the true value. When the validation set error no longer decreases, the training is stopped to prevent overfitting. S43, model evaluation and application step: use the test set data to perform a comprehensive evaluation on the trained model, calculate the mean square error (MSE) and mean absolute error (MAE) of various evaluation indicators, and if the model performance meets the predetermined requirements, apply the model in actual construction; During the support preloading stage, the load data collected in real time is input into the model to quickly predict the settlement value, and then compared and analyzed with the measured settlement value, and the loading strategy is adjusted in time according to the deviation; During the concrete pouring process, the model is used to predict the temperature stress change of concrete, according to the concrete temperature stress calculation formula: ； in, is the elastic modulus of concrete, is the linear expansion coefficient of concrete, is the temperature difference between the inside and outside of the concrete; Take effective temperature control measures based on the prediction results, including adjusting the curing temperature, optimizing the pouring time interval, etc.; During the prestressing stage, the model is used to predict the prestress loss, which includes the loss caused by anchor deformation and prestressing tendon shrinkage. , losses caused by friction between the prestressed tendons and the hole wall , the loss caused by the temperature difference between the prestressed tendons under tension and the equipment bearing the tension during concrete heating and curing , Losses caused by stress relaxation of prestressed tendons and losses caused by concrete shrinkage and creep ; The calculation formula for the loss caused by anchor deformation and prestressed tendon shrinkage is as follows: ； in, is the anchor deformation and prestressed tendon shrinkage value, is the effective length of the prestressed tendon; The calculation formula for the loss caused by friction between the prestressed tendons and the hole wall is as follows: ； in, To control the stress of tension, To consider the friction coefficient of local deviation per meter of the channel length, is the length of the channel from the tensioning end to the calculation section, is the friction coefficient between the prestressed tendons and the hole wall, It is the sum of the angles between the tension end and the tangent line of the calculated section curve channel part; According to the prediction results, corresponding measures are taken during the tensioning process, including increasing the tensioning control force and optimizing the anchoring process.

10. The construction method of the combined support system for the construction of the continuous beam for the combined highway and railway construction according to claim 9 is characterized in that: In the prestress loss calculation process of step S53, the above-mentioned losses are accumulated to obtain the total prestress loss calculation formula as follows: According to the calculation results of the total prestress loss, the prestress loss can be effectively compensated by increasing the tension control force and optimizing the anchoring system.

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