A method and system for controlling the laying of ballastless track for a large-span dual-purpose steel truss cable-stayed bridge for road and rail

Abstract

The present application discloses a method and system for controlling the alignment of ballastless track on a large-span dual-use steel truss cable-stayed bridge for road and rail, comprising: (1) constructing a monitoring system for the large-span dual-use steel truss cable-stayed bridge for road and rail; (2) establishing a refined analysis model for the large-span dual-use steel truss cable-stayed bridge for road and rail; (3) analyzing the influence of the upper highway load on the alignment of the lower railway track; (4) laying out a CPIII precision measurement network and establishing a real-time correction and prediction model for the CPIII precision measurement network; (5) adjusting the cables and preliminarily correcting the alignment of the beam surface; (6) constructing other ancillary facilities on the bridge in addition to the track step by step and establishing a mapping relationship between the second-phase constant load and the alignment of the bridge surface; (7) constructing the ballastless track on the bridge; and (8) acceptance of the alignment of the track. The present invention fully considers various factors affecting the alignment of the track on the large-span dual-use steel truss cable-stayed bridge during the construction process, and adopts a comprehensive monitoring system, theoretical analysis, and various construction measures to ensure the alignment accuracy of the ballastless track on the large-span dual-use steel truss cable-stayed bridge for road and rail.

Description

Technical Field

[0001] The present invention relates to the technical field of alignment adjustment for ballastless track construction on large-span bridges, and in particular to a method and system for controlling the alignment of ballastless track on a large-span dual-purpose steel truss cable-stayed bridge for road and rail. Background Art

[0002] my country has a vast territory, complex terrain, numerous rivers and lakes, and a crisscross network of various water and land transportation networks. When constructing high-speed railways, large-span bridges are often required. Among them, dual-use cable-stayed bridges for road and rail are widely used in railway construction due to their large spans, fewer bridge foundations, ease of crossing wide obstacles, and beautiful appearance. At the same time, dual-use cable-stayed bridges for road and rail have greatly improved the transportation capacity of traffic and are one of the most commonly used structural types of modern railway bridges. At present, the track structures laid on large-span bridges are mainly ballasted tracks and ballastless tracks. The deck of the ballasted track is paved with ballast, and the roadbed itself has a large adjustment range, but it imposes a large dead load on the bridge and often limits the driving speed.

[0003] Using a ballastless track structure on a bridge can extend the maintenance cycle of the track structure, improve line utilization and track smoothness, and is also an effective way to reduce the dead load on the bridge. High-speed railway ballastless track requires high construction precision due to its high smoothness, comfort, and durability requirements. However, long-span cable-stayed bridges are flexible bridges and are subject to significant deformation due to gravity loads, temperature loads, and other factors. The CPIII precision measurement and control network is also subject to constant changes due to wind speed, temperature, and load. The track precision measurement and control network has large layout errors, making track accuracy difficult to control. All of these factors pose difficulties and challenges to the installation of ballastless track on long-span bridges. Therefore, ensuring that the construction alignment of ballastless track on long-span bridges meets the design and acceptance requirements of the specifications and that the real-time control and adjustment of the track alignment during construction are key issues.

[0004] Currently, there are related methods for controlling the linear shape of track structures on large-span cable-stayed bridges. For example, patent CN110219246A discloses a method for constructing ballastless track on a large-span flexible bridge. However, the patent focuses on the layout of CPIII and the construction process of the ballastless track, and relatively little consideration is given to the impact of the second-phase constant load on the bridge on the linear shape of the beam surface. Patent CN110846958B discloses a method for controlling the linear shape accuracy of ballastless track construction on a cable-stayed bridge. Patent CN117077251A discloses a method for controlling the linear shape of ballastless track with a large-span steel truss structure. Patent CN116837672A discloses a method for laying ballastless track on a large-span bridge. All of the above patents require a preloading process for the large-span bridge, which makes the construction process relatively complicated and affects the construction period. Patent CN117090140A discloses a method for constructing ballastless track for large-span cable-stayed bridges. Although this patent does not require preloading, it takes into account fewer factors affecting the bridge alignment and mainly uses finite element models for correction, which is relatively different from the actual situation on site. The numerous influencing factors make it difficult to control the final track alignment laying accuracy.

[0005] In addition, in large-span dual-use steel truss cable-stayed bridges for road and rail, the road deck and the railway deck are integrated, with the road deck generally located on top and the railway deck generally located on the bottom, to minimize the mutual influence between the two. However, the overall stiffness of large-span bridges is relatively small and is significantly affected by external loads. During the construction of the railway bridge deck track, the impact of highway loads, including dead loads, vehicle live loads, and vibrations, on the alignment of the lower railway bridge cannot be ignored. The above-mentioned existing patents are all for traditional cable-stayed bridges and do not involve large-span dual-use steel truss cable-stayed bridges for road and rail, which also need to consider the impact of highway loads on the alignment of large-span bridges. Summary of the Invention

[0006] In response to the technical problems existing in the existing technology, this patent proposes a method and system for controlling the linearity of the ballastless track laying of a large-span dual-purpose steel truss cable-stayed bridge for road and rail. During the construction process, the various factors affecting the linearity of the track of a large-span bridge are fully considered, and a comprehensive monitoring system, theoretical analysis, and multiple construction measures are adopted simultaneously to ensure the linearity accuracy of the ballastless track laying of a large-span dual-purpose steel truss cable-stayed bridge for road and rail.

[0007] In a first aspect, the present invention provides a method for controlling the alignment of ballastless track during the laying of a large-span dual-purpose steel truss cable-stayed bridge for road and rail, comprising the following steps:

[0008] Step 1. Build a monitoring system for a large-span dual-use steel truss cable-stayed bridge to monitor bridge response and environmental information.

[0009] Step 2. Establish an initial finite element model to simulate the various construction processes of the bridge track. Based on the monitoring system of the large-span dual-use steel truss cable-stayed bridge for road and rail, modify the parameters of the initial finite element model and establish a refined analysis model of the large-span dual-use steel truss cable-stayed bridge for road and rail.

[0010] Step 3. Analyze the effect of the upper highway bridge deck on the stress and deformation of the lower railway bridge deck during construction based on the refined analysis model of the large-span dual-use steel truss cable-stayed bridge;

[0011] Step 4. Deploy the CPIII precision measurement network and establish a real-time correction model for the CPIII precision measurement network to correct the CPIII precision measurement network;

[0012] Step 5. Before the construction of the track structure and ancillary facilities, adjust the pre-camber of the bridge to be laid by adjusting the cables to correct the beam surface line shape;

[0013] Step 6. Construct all ancillary facilities on the bridge, excluding the track, step by step. Based on the monitoring system for large-span dual-use steel truss cable-stayed bridges and analysis of the impact of the upper highway bridge deck on the stress and deformation of the lower railway bridge deck during construction, the theoretical alignment during ballastless track laying is predicted.

[0014] Step 7. Conduct ballastless track construction on the bridge based on the theoretical alignment during ballastless track laying.

[0015] Step 8. Acceptance inspection of track laying alignment.

[0016] Furthermore, the monitoring system for the large-span dual-purpose steel truss cable-stayed bridge for road and rail in step 1 includes an arrayed fiber Bragg grating measurement front end, a fiber Bragg grating signal acquisition and demodulation instrument, a monitoring data intelligent analysis module, and a visualization module;

[0017] The fiber Bragg grating measurement front end is used to collect bridge response information and environmental information to obtain monitoring data, and the monitoring data includes temperature, second-phase dead load, wind load, and cable force;

[0018] The fiber Bragg grating signal acquisition and demodulation instrument is used to demodulate the optical signal of the fiber Bragg grating measurement front end into analyzable monitoring data;

[0019] The monitoring data intelligent analysis module compares the pre-input design information with the monitoring data to determine whether the monitoring data is erroneous data, and stores it after removing the erroneous data;

[0020] The monitoring data intelligent analysis module compares the real-time monitoring data with the historical monitoring data to make linear predictions, and issues early warnings and forecasts for abnormal data by setting limits;

[0021] The visualization module is based on BIM and GIS technology and is used for visual display and monitoring of monitoring data. It displays the status of the designed bridge and the comparison between the alignment under the ideal design state and the alignment of the bridge at different construction stages.

[0022] Furthermore, the establishment of a refined analysis model of a large-span dual-purpose steel truss cable-stayed bridge for road and rail in step 2 includes:

[0023] Collect the design parameters of bridge piers and main beams to establish the initial finite element model;

[0024] Based on the initial finite element model, simulation calculation and stress analysis were performed on each construction process of the bridge track;

[0025] By comparing the monitoring data of the monitoring system of the large-span dual-purpose steel truss cable-stayed bridge for road and rail with the theoretical data calculated by the initial finite element model, the model parameters of the initial finite element model were corrected, and a refined analysis model of the large-span dual-purpose steel truss cable-stayed bridge for road and rail was established.

[0026] Further, the step 3 comprises:

[0027] Based on the refined analysis model of a large-span dual-use steel truss cable-stayed bridge for railway and road use, the stress and deformation variation patterns of the highway bridge deck under different dead and live loads before the railway bridge track construction were calculated, and the deformation envelope curves of the railway bridge deck under different highway bridge loads were obtained.

[0028] When setting the pre-camber of the lower railway bridge deck, the deformation envelope curve of the railway bridge deck under different loads of the highway bridge deck is superimposed, so that under the constant load of the upper highway bridge, the alignment of the lower railway track is theoretically a straight line with a flat slope;

[0029] When vehicles pass through the upper highway bridge, the lower railway track is laid with a pre-camber setting of half the railway design static and live load;

[0030] Under other combined loads of the highway bridge, the track alignment of the lower railway bridge changes within the deformation envelope curve of the railway bridge deck under different loads on the highway bridge deck.

[0031] Furthermore, the step 4 includes:

[0032] Deployment of CPIII precision measurement network;

[0033] Based on the deformation of each measuring point of the bridge monitored by the monitoring system of the large-span dual-use steel truss cable-stayed bridge for road and rail, the CPIII key control points are determined;

[0034] Combining the effects of temperature and wind speed on the main bridge, the CPIII measurement boundary conditions were derived;

[0035] Based on the monitoring results of the vertical displacement of the bridge deck, temperature field monitoring, bridge expansion and contraction deformation monitoring, and CPIII control point coordinates before the main bridge construction, taking into account the real-time temperature on the bridge and combining the plane and elevation relationship of the CPIII key control points relative to the bridge tower control points, a real-time correction model of the CPIII points with three-dimensional coordinates in the bridge axis coordinate system was established; the three-dimensional coordinates of each CPIII control point were corrected.

[0036] Furthermore, the step 5 includes:

[0037] Before the construction of the track structure and ancillary facilities, if the pre-camber of the bridge to be laid is adjusted by adjusting the cables under the temperature of the bridge system, the actual bridge line shape will be close to the designed line shape of the beam surface;

[0038] If the system temperature is not exceeded, the bridge alignment is corrected based on the refined analysis model of the large-span dual-purpose steel truss cable-stayed bridge for highway and railway use.

[0039] Furthermore, the step 6 includes:

[0040] First, construct the bridge's ancillary facilities, excluding the tracks. The weight of each type of ancillary facility is then applied step by step. The impact of the different dead loads on the bridge's alignment is monitored using the monitoring system for large-span dual-use steel truss cable-stayed bridges. Cable adjustment targets are calculated based on a refined analysis model for large-span dual-use steel truss cable-stayed bridges, and the bridge deck alignment is corrected using cable adjustment.

[0041] After the construction of all ancillary facilities on the bridge, excluding the track, was completed, the impact of the second phase of the dead load on the ancillary facilities on the track alignment was calculated and analyzed based on the load and temperature conditions before ballastless track construction, using the refined analysis model for large-span dual-use steel truss cable-stayed bridges for road and rail. Based on the changes in the bridge deck alignment, stiffness corrections were made to the key influencing parameters of the refined analysis model for large-span dual-use steel truss cable-stayed bridges for road and rail.

[0042] Based on the monitoring system of large-span dual-purpose steel truss cable-stayed bridge for road and railway, and the influence of the stress and deformation of the upper highway bridge surface on the lower railway bridge deck during the construction process in step 3, the theoretical line shape during the laying of ballastless track is predicted.

[0043] Furthermore, the step 6 further includes:

[0044] Combining the deformation envelope curves and monitoring data of the lower railway bridge track alignment under different loads on the railway bridge deck and the highway bridge deck, the linear variation law of the bridge track is analyzed, and the functional relationship between the bridge deformation y, temperature t, and constant load p is established to improve and supplement the bridge deformation under extreme loads that cannot be measured under actual monitoring conditions:

[0045] y=f(t,p,x)

[0046] Where x is the horizontal coordinate of the bridge deformation monitoring point.

[0047] Furthermore, the step 7 includes:

[0048] Based on the predicted theoretical alignment during ballastless track laying, the ballastless track on the bridge is constructed sequentially. The adjustability of the track base plate is used to eliminate local alignment errors in the main beam segments. The self-compacting concrete layer is then used to fine-tune the track alignment. Finally, fasteners are used to make sub-millimeter adjustments to the track alignment.

[0049] In another aspect, the present invention provides a linear control system for laying ballastless track of a large-span dual-purpose steel truss cable-stayed bridge for road and rail, comprising:

[0050] Monitoring system construction module: It is used to build a monitoring system for a large-span dual-use steel truss cable-stayed bridge for road and rail to monitor bridge response information and environmental information;

[0051] Refined Analysis Model Construction Module: This module is used to establish an initial finite element model to simulate the various construction processes of the bridge track. Based on the monitoring system of the large-span dual-use steel truss cable-stayed bridge for road and rail, the parameters of the initial finite element model are modified to establish a refined analysis model for the large-span dual-use steel truss cable-stayed bridge.

[0052] Analysis module: This module is used to analyze the influence of the upper highway bridge deck on the stress and deformation of the lower railway bridge deck during construction based on the refined analysis model of the large-span dual-purpose steel truss cable-stayed bridge;

[0053] A CPIII precision measurement network construction module is used to deploy the CPIII precision measurement network and establish a CPIII precision measurement network real-time correction model to correct the CPIII precision measurement network;

[0054] The beam surface linear correction module is used to correct the beam surface linear shape by adjusting the pre-camber of the bridge to be laid track by adjusting cables before the construction of the track structure and ancillary facilities;

[0055] Theoretical alignment prediction module: This module is used for the step-by-step construction of other ancillary facilities on the bridge, excluding the track. Based on the monitoring system of a large-span dual-use steel truss cable-stayed bridge for highway and railway use and analysis of the impact of the upper highway bridge deck on the stress and deformation of the lower railway bridge deck during construction, the theoretical alignment during ballastless track laying is predicted.

[0056] Theoretical alignment construction module: It is used to construct ballastless track on bridges based on the theoretical alignment during ballastless track laying;

[0057] Linear acceptance module: It is used to accept the track laying line.

[0058] Compared with the prior art, the present invention has the following beneficial effects:

[0059] The monitoring system constructed by the present invention can continuously monitor the stress conditions of the beam surface, including temperature, deformation, acceleration, stress magnitude, and change trends, in real time. The monitoring data is comprehensive, rich, and real-time, providing timely insights into the stress and deformation conditions of the bridge deck. The use of a unified and highly consistent signal transmission line for monitoring fiber Bragg gratings (FBGs) improves the accuracy of monitoring results. The arrayed FBGs installed simultaneously can be used for track laying during construction and for post-operation and maintenance monitoring of the track after completion and opening. This system guides engineering departments in timely inspection and maintenance of ballastless track, ensuring the construction quality and service status of the bridge track throughout its lifecycle. This system can monitor a variety of health indicators of the bridge track service environment, providing richer monitoring data that comprehensively and reliably reflects the track's service status. This system also addresses the issue of unintuitive bridge alignment monitoring results by visually displaying measurement data through BIM and GIS technologies. Data processing, computational analysis, and result presentation are all performed on a cloud platform, offering strong adaptability and reliability. The computational module is efficient and accurate, eliminating the possibility of human error, and boasts a high degree of automation and controllability.

[0060] The present invention proposes a method for controlling the alignment of ballastless track during the laying of a large-span dual-purpose steel truss cable-stayed bridge for road and rail. The method calculates the weight of other ancillary facilities on the bridge and uses graded loading to determine the corresponding relationship between load and main beam deformation. By adjusting the cable tension of the stay cables, the alignment of the main beam is systematically and extensively adjusted to achieve a relatively reasonable alignment with centimeter-level accuracy. The adjustability of the track base plate is fully utilized to eliminate local alignment errors of main beam segments. A self-compacting concrete layer is then used to fine-tune the track alignment with millimeter-level accuracy. Finally, fasteners are used to perform sub-millimeter adjustments to the track alignment, ensuring that the ballastless track laying and the track surface alignment after the bridge is completed meet the requirements.

[0061] The refined analysis model of the large-span dual-purpose steel truss cable-stayed bridge for road and rail established in the present invention can take into account the influence of various factors on the linear shape of the bridge structure, compare theoretical data with field test data, conduct feedback analysis and adjustment, and promptly discover whether large deviations occur during the construction process, implement prompt warnings or emergency treatment, ensure the safety of the bridge construction process and the permanent structure after the bridge is completed, and ensure the smooth linear shape of the bridge deck after the bridge is completed.

[0062] This invention fully considers the impact of various combined loads from the upper highway bridge on the alignment of the railway bridge deck during track alignment construction. When setting the pre-camber of the lower railway bridge deck, an envelope curve representing the impact of the upper highway bridge on the railway alignment is superimposed. This offsets the effects of the track deck pre-camber and the train's static and live loads on the track structure alignment during train travel. This minimizes the impact of subsequent construction of the upper highway train load on the lower track alignment, improving the smoothness of train operation while ensuring that the railway track alignment is inspected and meets high-speed train travel requirements, further ensuring the alignment of the bridge track.

[0063] The present invention proposes a method for laying ballastless track and controlling the alignment of a large-span dual-purpose steel truss cable-stayed bridge for road and rail. This method combines environmental factors such as wind speed and temperature, as well as the influence of bridge loads at different construction stages on alignment, with monitoring data used to establish a CPIII real-time coordinate correction and prediction model. This method can control and understand the alignment and variation patterns of the track structure at each construction stage for laying track on a large-span bridge. Furthermore, the method compares and verifies real-time on-site data analysis with theoretical calculations, allowing for timely model adjustments and addressing the difficulty in controlling accuracy during construction.

[0064] The construction alignment adjustment method provided by the present invention abandons the preloading process, and the construction process is relatively simple. By establishing a comprehensive monitoring network, the measured data is combined with the theoretical analysis model for mutual correction, early warning and forecasting, which can effectively ensure the alignment of the bridge. The alignment control method of equivalent load replacement is abandoned, and the finite element model is corrected according to the actual construction situation. The process is simplified and the finite element model is corrected more accurately to ensure that the laying accuracy of the ballastless track meets the standards. In particular, the problem of preload quality accuracy control and the related material and equipment procurement and layout processes that may occur during the preloading process are not required by the present invention, which greatly saves construction time.

[0065] The present invention proposes a method for laying and controlling the alignment of ballastless track on a large-span dual-purpose steel truss cable-stayed bridge for road and rail. The pre-camber set after track laying adopts a herringbone slope plus a vertical curve, so that the bridge alignment is consistent with the line alignment. At the same time, the pre-camber is simplified to a herringbone slope, thereby offsetting the effects of the static and live loads of railway trains, and superimposing the effects of the upper vehicle load on the bridge alignment. This ensures that the track surface alignment at each stage of ballastless track laying and after the bridge is completed meets the standard acceptance requirements, further ensuring the track alignment acceptance and driving safety. At the same time, the design, construction and acceptance are more convenient, without affecting driving safety and comfort, and meeting the requirements of higher operating speeds. BRIEF DESCRIPTION OF THE DRAWINGS

[0066] In order to more clearly illustrate the technical solutions in the present invention or the prior art, a brief introduction is given below to the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0067] Figure 1 This is an overall flow chart of a method for laying ballastless track and controlling the linear shape of a large-span dual-purpose steel truss cable-stayed bridge for road and rail transport according to the present invention;

[0068] Figure 2 This is a diagram showing the composition of a monitoring system for a ballastless track laying and linear control method for a large-span dual-purpose steel truss cable-stayed bridge for road and rail, according to the present invention.

[0069] Figure 3This is a cross-sectional view of the fiber Bragg grating arrangement of a ballastless track laying and linear control method for a large-span dual-purpose road-rail steel truss cable-stayed bridge according to the present invention.

[0070] Figure 4 This is a cross-sectional view of a CRTSIII type slab ballastless track on a bridge, according to a method for laying and linear control of a ballastless track on a large-span dual-purpose steel truss cable-stayed bridge for road and rail.

[0071] Figure 5 The invention relates to a method for controlling the laying line shape of a ballastless track of a large-span dual-purpose steel truss cable-stayed bridge for road and rail, and describes the influence of an upper highway layer on the line shape of a bridge track of a lower railway layer.

[0072] Figure 6 The present invention is a schematic diagram of the bridge alignment of a ballastless track laying and alignment control method for a large-span dual-purpose steel truss cable-stayed bridge for road and rail.

[0073] In the figure: 1. Rail, 2. Fastener, 3. Track plate, 4. Self-compacting concrete, 5. Base plate, 6. Beam groove, 7. Fiber Bragg grating (FBG), 8. Cable, 9. Beam surface. DETAILED DESCRIPTION

[0074] To make the above-mentioned objects, features, and advantages of the present application more clearly understood, the specific embodiments of the present application are described in detail below with reference to the accompanying drawings. The following description sets forth many specific details to facilitate a full understanding of the present application. However, the present application can be implemented in many other ways than those described herein, and those skilled in the art can make similar improvements without violating the scope of the present application. Therefore, the present application is not limited to the specific embodiments disclosed below.

[0075] Example 1

[0076] like Figure 1 As shown in the figure, the present invention proposes a method for controlling the alignment of ballastless track on a large-span dual-purpose steel truss cable-stayed bridge for road and rail, comprising the following steps: (1) constructing a monitoring system for a large-span dual-purpose steel truss cable-stayed bridge for road and rail; (2) establishing a refined analysis model for a large-span dual-purpose steel truss cable-stayed bridge for road and rail; (3) analyzing the influence of the upper highway load on the alignment of the lower railway track; (4) laying out the CPIII precision measurement network and establishing a real-time correction and prediction model for the CPIII precision measurement network; (5) adjusting the cables and preliminarily correcting the alignment of the beam surface; (6) constructing other ancillary facilities on the bridge except the track step by step and establishing a mapping relationship between the second-phase constant load and the alignment of the bridge surface; (7) constructing the ballastless track on the bridge: ① constructing the base plate, isolation buffer cushion layer and elastic cushion layer; ② rough laying and fine-tuning the track plate; ③ pouring self-compacting concrete; ④ laying the rails and fasteners and fine-tuning the line; and (8) acceptance of the alignment of the track laying.

[0077] The five key steps mentioned above, namely, step-by-step construction of other ancillary facilities on the bridge, laying of base plates, rough laying and fine-tuning of track plates, pouring of self-compacting concrete, and installation and fine-tuning of rail fasteners, require comparison of the deviation between the actual alignment of the bridge track and the theoretical design pre-camber, and timely correction of the construction alignment based on the measured conditions. At the same time, it is also necessary to combine the measured data to compare and analyze the actual alignment of the main bridge with the theoretical alignment, and to correct the model parameters to accurately guide the subsequent construction process.

[0078] S1: Construction of a monitoring system for a large-span dual-use steel truss cable-stayed bridge for road and rail

[0079] The monitoring system for the large-span dual-purpose steel truss cable-stayed bridge for road and rail is based on arrayed fiber Bragg grating (FBG) laying technology. FBG displacement, strain, vibration acceleration, and temperature sensors are installed on the beam surface 9. Fiber Bragg grating (FBG) strain sensors, air temperature, and wind speed sensors are installed at the position of the cable stays 8 on the large-span bridge to monitor changes in the tension of the cable stays 8, air temperature, and wind speed. The system obtains key parameters of the bridge's service status, enabling full perception, prediction, and early warning of the deformation and service environment of the large-span bridge.

[0080] The monitoring system for the large-span dual-purpose steel truss cable-stayed bridge for road and railway includes an array fiber Bragg grating measurement front end, a fiber Bragg grating signal acquisition and demodulation instrument, a monitoring data intelligent analysis module, and a visualization module. Figure 2 shown.

[0081] The fiber Bragg grating measurement front end is used to collect monitoring data on bridge response and environmental information, using an arrayed fiber Bragg grating to monitor key parameters such as deformation, temperature, cable tension, and lateral wind speed across the entire bridge deck. The fiber Bragg grating signal acquisition and demodulation instrument is used to demodulate optical signals into analyzable data. The monitoring data intelligent analysis module automatically determines whether the monitoring data is erroneous based on pre-input design information and monitoring data, and stores the data after eliminating erroneous data, thus enabling monitoring data storage. The monitoring data intelligent analysis module, based on a deep learning algorithm, conducts a longitudinal comparison of existing and historical monitoring data, enabling linear prediction and warning of abnormal data by setting limits. The visualization module, based on BIM and GIS technology, is used for visual display and monitoring of measurement information. It can display information on the designed bridge's completed state, and compare the linear shape under the ideal design state with the linear shape of bridges at different construction stages.

[0082] like Figure 3As shown, after the bridge is completed, grooves 6 are chiseled longitudinally along the track on both sides of the bridge deck, outside the rail base plate 5. The dimensions of the grooves 6 meet the requirements for laying arrayed fiber Bragg gratings (FBGs), with a depth of 15 to 25 mm. Fine stone mortar is then poured into the grooves 6 to secure the connection. Alternatively, the FBGs can be laid directly on the bridge surface. With this approach, special care must be taken to prevent repeated rolling of the FBGs 7 during subsequent construction, which could cause them to fall off or break. A protective cover effectively protects the warpage monitoring cable, which is secured to the bridge surface using fasteners such as expansion screws. The FBGs 7 within the grooves are arrayed FBG stress cables integrated with multiple FBG sensors. These cables continuously measure bridge temperature, deformation, stress, and acceleration, providing timely insight into the stress and deformation conditions of the bridge deck. The density of the FBG sensors within the connecting cable can be adjusted based on specific circumstances. For example, in this example, the spacing between adjacent FBG vibration sensors is within a range of 0.1 to 0.2 m.

[0083] The fiber Bragg grating (FBG) sensors 7 in the slots collect bridge temperature, deformation, stress, and acceleration in real time. The FBG signal demodulator receives and demodulates the data into analyzable data, which is then sent to the intelligent monitoring data analysis module. Given the long length of ballastless track, multiple FBG data demodulators are preferably provided to ensure the accuracy and reliability of the monitoring data. Preferably, each FBG data demodulator is used to acquire monitoring information from two sections of FBG array monitoring cables located in front and behind it. In one embodiment, two adjacent FBG data demodulators are connected in series by a single cable. Within this single cable, at a certain point serving as a demarcation point, the FBG sensor in front of the demarcation point transmits monitoring information to the FBG data demodulator in front, and the FBG sensor behind the demarcation point transmits monitoring information to the FBG data demodulator behind. This can be achieved by configuring the light emission directions of the FBG sensors in the optical cable. Preferably, a FBG data demodulator is positioned at the bridge tower to perform data demodulation, storage, and calculation.

[0084] The array fiber grating cable is a cable in which multiple fiber grating sensors are integrated in a single optical cable. It is an existing product with the characteristics of wide monitoring coverage (covering more than 10km as needed), high measurement accuracy, and small spacing between sensor units (the minimum spacing can be 1cm). The specific structure will not be described here.

[0085] The fiber Bragg grating (FBG) data demodulator is preferably capable of compositely demodulating stress, strain, and vibration information. It receives monitoring information transmitted by the slot monitoring cable and demodulates it into a demodulated signal, which is then transmitted to the backend processor. The fiber Bragg grating (FBG) data demodulator is also an existing device; it can be electrically or communicatively connected to the backend processor.

[0086] S2: Establish a detailed analysis model for a large-span dual-use steel truss cable-stayed bridge for road and rail

[0087] The key parameters such as the design elastic modulus and cross-sectional size parameters of the piers and main beams, and the design load data are collected to construct an initial finite element model. Based on the initial finite element model, simulation calculations and force analysis are carried out on each construction process of the bridge track. The initial finite element model parameters are corrected through monitoring data to establish a refined analysis model of a large-span dual-purpose steel truss cable-stayed bridge for road and rail. This ensures that the theoretical calculated deformation of the model is consistent with the measured line shape at the track line shape detection temperature, thus guiding subsequent construction.

[0088] The structural sensitivity analysis is performed using the refined analysis model of the large-span dual-purpose steel truss cable-stayed bridge for road and rail. Based on the current working condition model, the unit length of the sling is changed in sequence (assuming 1 cm is the unit length of the sling change). The changes in the cable forces of all other slings and the linear changes of all bridge deck positions can be calculated under the current change in the unit length of the sling. On this basis, the cable force measurement points are optimized to optimize the monitoring data of the monitoring system of the large-span dual-purpose steel truss cable-stayed bridge for road and rail.

[0089] The refined analysis model of the large-span dual-purpose steel truss cable-stayed bridge for road and rail can take into account the influence of various factors on the linear shape of the bridge structure, and use theoretical calculations to analyze and predict the linear shape of the bridge in the completed state.

[0090] S3: Analyze the impact of upper highway loads on the lower railway track alignment

[0091] When constructing the railway bridge deck track line shape, it is necessary to consider the influence of various combined loads of the upper highway bridge on the line shape. Combined with real-time monitoring data, using the refined analysis model of the large-span dual-purpose steel truss cable-stayed bridge for road and railway, theoretical calculation and analysis are made on the influence of the upper highway bridge surface on the stress and deformation during the construction process of the lower railway bridge deck track. Before the construction of the railway bridge deck track, the stress and deformation variation law of the highway bridge deck under different constant loads and live loads is theoretically calculated to obtain the deformation envelope curve of the railway bridge deck under different loads of the highway bridge deck; when the pre-arch of the lower railway bridge deck is set, the deformation envelope curve of the railway bridge deck under different loads of the highway bridge deck is superimposed, so that under the constant load of the upper highway bridge, the line shape of the lower railway track is theoretically a straight line and flat slope; under the vehicle load of the upper highway bridge When a train passes by, the pre-camber of the track surface of the lower railway track is set to half of the designed static and live load of the railway when laying the track, so as to offset the influence of the static and live load of the railway train. Under the influence of other combined loads of the highway bridge, the track line shape of the lower railway bridge changes within the envelope curve of its influence. By setting this pre-camber, when the train is running, the influence of the track surface pre-camber and the static and live load of the train on the track structure line shape is offset, and the influence of the subsequent construction of the upper highway train load on the lower track line shape is minimized, thereby improving the smoothness of the line train operation, so as not to affect the acceptance of the railway layer track line shape and the high-speed running requirements of the train, and further ensure the track line shape on the bridge.

[0092] S4: Deploy the CPIII precision measurement network and establish a real-time correction and prediction model for the CPIII precision measurement network

[0093] During a period of the day when the temperature is relatively stable, a through-measurement of the control base points on the fixed auxiliary objects outside the two anchor spans is performed to ensure a smooth connection of the bridge and the accuracy of ballastless track construction. The precision measurement network layout and measurement are conducted between 00:00 and 03:00 in the morning, with fixed points set at the main tower. The actual bridge alignment is obtained using a fiber Bragg grating (FBG) monitoring system and compared and corrected with the theoretical calculation results of a refined analysis model for large-span dual-use steel truss cable-stayed bridges for road and rail. The CPIII key control points are determined based on the deformation of each measuring point on the bridge, and the CPIII measurement boundary conditions are derived based on the effects of temperature and wind speed on the main bridge. Based on the monitoring results of the vertical displacement of the bridge deck before main bridge construction, temperature field monitoring, bridge expansion and contraction deformation monitoring, and CPIII control point coordinates, and taking into account factors such as the real-time temperature on the bridge, a real-time correction model of the CPIII points with three-dimensional coordinates in the bridge axis coordinate system is established based on the plane and elevation relationship of the CPIII control points relative to the tower control points. The three-dimensional coordinates of each CPIII control point are corrected to accurately guide subsequent track alignment construction.

[0094] The layout of the CPIII precision measurement network also needs to consider the impact of the vehicle load of the upper highway bridge on the adjustment of the construction alignment of the lower railway track, and timely modify the CPIII precision measurement network.

[0095] S5: Adjust the cables and make preliminary corrections to the beam surface shape

[0096] Before construction of the track structure and ancillary facilities, the pre-camber of the bridge to be laid is adjusted using cable adjustments to ensure that the actual bridge alignment approximates the designed beam surface alignment. At the bridge system temperature, the pre-camber height is equal to the height of the impact of the subsequently constructed base plate 5, track slab, self-compacting concrete adjustment layer, and rail 1 on the track alignment. This fully offsets the impact of the pre-camber and alignment, further improving the track alignment accuracy. If the bridge alignment is not within the system temperature, the bridge alignment must be corrected using a theoretical calculation model.

[0097] S6: Gradually construct other ancillary facilities on the bridge except the track, and establish the mapping relationship between the second phase dead load and the bridge deck alignment

[0098] First, construct the bridge's ancillary facilities, excluding the track. Calculate the weight of each type of ancillary facility and apply it step by step. A monitoring system will be used to monitor the impact of the different dead loads on the bridge's alignment. After the ancillary facilities are completed, adjust the stay cables based on the theoretical beam alignment calculated based on the load and temperature conditions before ballastless track construction. After cable adjustment, inspect the beam alignment, reviewing geometric elements such as beam elevation and centerline, and address any deviations promptly.

[0099] After the loads of the other ancillary facilities are applied, if the actual bridge deck alignment is significantly different, cable adjustment is performed; before the cable adjustment, the relationship between the cable force of the entire bridge and the bridge deformation is analyzed, and the bridge deformation is predicted and verified by the cable force; the cable adjustment target value is calculated through the refined analysis model of the large-span dual-purpose road-rail steel truss cable-stayed bridge, and the bridge alignment changes are monitored in real time through the monitoring system to provide early warning and forecast; finally, the bridge deck alignment is corrected to make the bridge deck alignment as close to the design alignment as possible.

[0100] Combined with the refined analysis model of the large-span dual-purpose steel truss cable-stayed bridge for road and rail, the impact of the second-phase constant load of the bridge's ancillary facilities (bridge deck waterproofing layer, protective layer structure, cables, and contact network) on the track alignment is calculated and analyzed; the ancillary facilities are constructed, and the changes in the bridge deck alignment before and after construction are monitored. Based on the changes in the bridge deck alignment, the stiffness correction of the key influencing parameters of the refined analysis model of the large-span dual-purpose steel truss cable-stayed bridge for road and rail is carried out.

[0101] Before the construction of the bridge deck track, the linear change law of the bridge deck at different temperatures is monitored, and a mapping relationship between temperature and bridge deck linear shape is established; the second-phase constant load on the bridge is applied step by step on the refined analysis model of a large-span dual-purpose road-rail steel truss cable-stayed bridge; the linear change law of the beam surface under different second-phase constant load conditions is obtained; the linear change law of the bridge track is analyzed by combining the deformation envelope curve calculated by bridge track theory and the bridge linear monitoring data, and a fitting is performed using a combination of trigonometric functions and polynomials to establish a functional relationship y=f(t,p,x) between the bridge deformation y and key influencing factors such as temperature t and constant load p. By establishing this function, the deformation of the bridge under extreme loads that cannot be measured under actual monitoring conditions is improved and supplemented.

[0102] S7: Ballastless track construction on the bridge

[0103] The construction of the ballastless track on the bridge can only be implemented after the installation of other ancillary facilities on the bridge deck is completed. The construction of the ballastless track on the main bridge is carried out in the order of the main bridge side span first and then the main bridge middle span to prevent subsequent construction from affecting the main span line shape. The concrete construction of the base plate 5 of the main bridge middle span is completed by one-time pouring on one side, and the self-compacting concrete of the main bridge middle span is completed by one-time continuous pouring on both sides.

[0104] like Figure 4 and 5 As shown, the steps for constructing ballastless track on a bridge mainly include: 1) constructing the base plate 5, isolation buffer pad and elastic pad; 2) rough laying and fine-tuning the track plate 3; 3) pouring self-compacting concrete 4; 4) laying rails 1 and fasteners 2, and fine-tuning the line.

[0105] 1) Construction base plate, isolation cushion and elastic cushion

[0106] After achieving the theoretical calculated alignment, the basement was laid out and constructed according to the theoretical alignment before ballastless track construction. The basement alignment was measured and verified against the theoretical alignment under these conditions. The basement was laid out according to the design elevation and constructed to a designed thickness of 220mm. After the alignment was established and the basement formwork was erected, the basement concrete, rubber isolation cushioning layer, and elastic padding around the limit grooves were constructed according to standard operating procedures. The alignment of the completed baseplate 5 was adjusted based on the actual construction temperature.

[0107] Adjusting the cable tension can achieve a more reasonable main beam alignment, but it has little effect on adjusting local alignment differences between segments. When a segment's actual alignment deviates from the theoretical alignment, the adjustable thickness range of the track slab 3 can be fully utilized to eliminate local alignment errors in the main beam segment. After the ballastless track base plate 5 is constructed, its alignment should be compared with the theoretical alignment. The base plate 5 can eliminate beam surface alignment errors of ±20 mm.

[0108] 2) Rough laying and fine-tuning of track slab 3

[0109] According to the design layout requirements, the corresponding track slab 3 model is selected, and the track slab 3 is roughly laid according to the standard operating procedures. The theoretical line shape of the main bridge mid-span is calculated according to the load and temperature conditions after the slab layout, and the track slab 3 is fine-tuned according to this line shape.

[0110] 3) Self-compacting concrete construction

[0111] A pouring formwork and a clamping device are set on both sides of the track plate 3 to prevent the double-hole limit track plate 3 from floating up during the pouring of the sub-plate cushion layer; the self-compacting concrete 4 is constructed according to the standard process. The self-compacting concrete 4 layer of the type III track plate 3 is 103mm thick and is equipped with a steel mesh. Self-compacting can eliminate linear construction errors of -10 to +20mm.

[0112] 4) Track laying

[0113] When adjusting alignment using track thickness, the effect of weight changes caused by track thickness variations on alignment should be considered and the corresponding compensation value calculated. Finally, track laying fine-tuning is performed. Fastener 2 can eliminate alignment errors of -4 to +26 mm.

[0114] S8: Track laying alignment acceptance

[0115] like Figure 6As shown, the final track-laying alignment is configured with pre-camber, using a herringbone slope plus a vertical curve, while also factoring in the influence of the upper vehicle load on the bridge alignment. The pre-camber of the railway layer of the bridge includes both constant-load pre-camber and live-load pre-camber. Later creep deformation is considered constant-load deformation and factored into the constant-load pre-camber. The live-load pre-camber is calculated as half of the design static and live loads. The pre-camber setting is implemented during the construction process. This ensures that the track alignment at each stage of ballastless track laying and after bridge completion meets regulatory acceptance requirements, such as the acceptance criteria for the long-wave 60m chord and short-wave 10m chord limits, and the dynamic TQI indicator for evaluating and accepting the overall smoothness of the line.

[0116] Example 2

[0117] A specific embodiment of the present invention further provides a linear control system for laying ballastless track of a large-span dual-purpose steel truss cable-stayed bridge for road and rail, comprising:

[0118] Monitoring system construction module: It is used to build a monitoring system for a large-span dual-use steel truss cable-stayed bridge for road and rail to monitor bridge response information and environmental information;

[0119] Refined Analysis Model Construction Module: This module is used to establish an initial finite element model to simulate the various construction processes of the bridge track. Based on the monitoring system of the large-span dual-use steel truss cable-stayed bridge for road and rail, the parameters of the initial finite element model are modified to establish a refined analysis model for the large-span dual-use steel truss cable-stayed bridge.

[0120] Analysis module: This module is used to analyze the influence of the upper highway bridge deck on the stress and deformation of the lower railway bridge deck during construction based on the refined analysis model of the large-span dual-purpose steel truss cable-stayed bridge;

[0121] A CPIII precision measurement network construction module is used to deploy the CPIII precision measurement network and establish a CPIII precision measurement network real-time correction model to correct the CPIII precision measurement network;

[0122] The beam surface linear correction module is used to correct the beam surface linear shape by adjusting the pre-camber of the bridge to be laid track by adjusting cables before the construction of the track structure and ancillary facilities;

[0123] Theoretical alignment prediction module: This module is used for the step-by-step construction of other ancillary facilities on the bridge, excluding the track. Based on the monitoring system of a large-span dual-use steel truss cable-stayed bridge for highway and railway use and analysis of the impact of the upper highway bridge deck on the stress and deformation of the lower railway bridge deck during construction, the theoretical alignment during ballastless track laying is predicted.

[0124] Theoretical alignment construction module: It is used to construct ballastless track on bridges based on the theoretical alignment during ballastless track laying;

[0125] Linear acceptance module: It is used to accept the track laying line.

[0126] The above is only a preferred specific implementation method of the present application, but the scope of protection of the present application is not limited thereto. Any changes or replacements that can be easily thought of by any technician familiar with this technical field within the technical scope disclosed in this application should be covered by the scope of protection of the present application.

[0127] It should be understood that parts not elaborated in detail in this specification belong to the prior art.

[0128] It should be understood that the above description of the preferred embodiment is relatively detailed and cannot be regarded as limiting the scope of protection of the patent of the present invention. Under the guidance of the present invention, ordinary technicians in this field can also make substitutions or modifications without departing from the scope of protection of the claims of the present invention, which all fall within the scope of protection of the present invention. The scope of protection requested by the present invention shall be based on the attached claims.

Claims

1. A method for controlling the alignment of ballastless track laying for a large-span dual-purpose steel truss cable-stayed bridge for road and rail, characterized in that: The following steps are involved: Step 1. Build a monitoring system for a large-span dual-use steel truss cable-stayed bridge to monitor bridge response and environmental information. Step 2. Establish an initial finite element model to simulate the various construction processes of the bridge track. Based on the monitoring system of the large-span dual-use steel truss cable-stayed bridge for road and rail, modify the parameters of the initial finite element model and establish a refined analysis model of the large-span dual-use steel truss cable-stayed bridge for road and rail. Step 3. Analyze the effect of the upper highway bridge deck on the stress and deformation of the lower railway bridge deck during construction based on the refined analysis model of the large-span dual-use steel truss cable-stayed bridge; Step 4. Deploy the CPIII precision measurement network and establish a real-time correction model for the CPIII precision measurement network to correct the CPIII precision measurement network; Step 5. Before the construction of the track structure and ancillary facilities, adjust the pre-camber of the bridge to be laid by adjusting the cables to correct the beam surface line shape; Step 6. Construct all ancillary facilities on the bridge, excluding the track, step by step. Based on the monitoring system for large-span dual-use steel truss cable-stayed bridges and analysis of the impact of the upper highway bridge deck on the stress and deformation of the lower railway bridge deck during construction, the theoretical alignment during ballastless track laying is predicted. Step 7. Conduct ballastless track construction on the bridge based on the theoretical alignment during ballastless track laying. Step 8. Acceptance inspection of track laying alignment.

2. The method for controlling the laying alignment of ballastless track for a large-span dual-purpose steel truss cable-stayed bridge for road and rail according to claim 1, characterized in that: The monitoring system for the large-span dual-purpose steel truss cable-stayed bridge for road and rail in step 1 includes an arrayed fiber Bragg grating measurement front end, a fiber Bragg grating signal acquisition and demodulation instrument, a monitoring data intelligent analysis module, and a visualization module; The fiber Bragg grating measurement front end is used to collect bridge response information and environmental information to obtain monitoring data, and the monitoring data includes temperature, second-phase dead load, wind load, and cable force; The fiber Bragg grating signal acquisition and demodulation instrument is used to demodulate the optical signal of the fiber Bragg grating measurement front end into analyzable monitoring data; The monitoring data intelligent analysis module compares the pre-input design information with the monitoring data to determine whether the monitoring data is erroneous data, and stores it after removing the erroneous data; The monitoring data intelligent analysis module compares the real-time monitoring data with the historical monitoring data to make linear predictions, and issues early warnings and forecasts for abnormal data by setting limits; The visualization module is based on BIM and GIS technology and is used for visual display and monitoring of monitoring data. It displays the status of the designed bridge and the comparison between the alignment under the ideal design state and the alignment of the bridge at different construction stages.

3. The method for controlling the laying alignment of ballastless track for a large-span dual-purpose steel truss cable-stayed bridge for road and rail according to claim 2, characterized in that: The step 2 of establishing a refined analysis model for a large-span dual-purpose steel truss cable-stayed bridge for road and rail includes: Collect the design parameters of bridge piers and main beams to establish the initial finite element model; Based on the initial finite element model, simulation calculation and stress analysis were performed on each construction process of the bridge track; By comparing the monitoring data of the monitoring system of the large-span dual-purpose steel truss cable-stayed bridge for road and rail with the theoretical data calculated by the initial finite element model, the model parameters of the initial finite element model were corrected, and a refined analysis model of the large-span dual-purpose steel truss cable-stayed bridge for road and rail was established.

4. The method for controlling the laying alignment of ballastless track for a large-span dual-purpose steel truss cable-stayed bridge for road and rail according to claim 2, wherein: Described step 3 comprises: Based on the refined analysis model of a large-span dual-use steel truss cable-stayed bridge for railway and road use, the stress and deformation variation patterns of the highway bridge deck under different dead and live loads before the railway bridge track construction were calculated, and the deformation envelope curves of the railway bridge deck under different highway bridge loads were obtained. When setting the pre-camber of the lower railway bridge deck, the deformation envelope curve of the railway bridge deck under different loads of the highway bridge deck is superimposed, so that under the constant load of the upper highway bridge, the alignment of the lower railway track is theoretically a straight line with a flat slope; When vehicles pass through the upper highway bridge, the lower railway track is laid with a pre-camber setting of half the railway design static and live load; Under other combined loads of the highway bridge, the track alignment of the lower railway bridge changes within the deformation envelope curve of the railway bridge deck under different loads on the highway bridge deck.

5. The method for controlling the laying alignment of ballastless track for a large-span dual-purpose steel truss cable-stayed bridge for road and rail according to claim 1, characterized in that: The step 4 comprises: Deployment of CPIII precision measurement network; Based on the deformation of each measuring point of the bridge monitored by the monitoring system of the large-span dual-use steel truss cable-stayed bridge for road and rail, the CPIII key control points are determined; Combining the effects of temperature and wind speed on the main bridge, the CPIII measurement boundary conditions were derived; Based on the monitoring results of the vertical displacement of the bridge deck, temperature field monitoring, bridge expansion and contraction deformation monitoring, and CPIII control point coordinates before the main bridge construction, taking into account the real-time temperature on the bridge and combining the plane and elevation relationship of the CPIII key control points relative to the bridge tower control points, a real-time correction model of the CPIII points with three-dimensional coordinates in the bridge axis coordinate system was established; the three-dimensional coordinates of each CPIII control point were corrected.

6. The method for controlling the laying alignment of ballastless track for a large-span dual-purpose steel truss cable-stayed bridge for road and rail according to claim 1, characterized in that: The step 5 comprises: Before the construction of the track structure and ancillary facilities, if the pre-camber of the bridge to be laid is adjusted by adjusting the cables under the temperature of the bridge system, the actual bridge line shape will be close to the designed line shape of the beam surface; If the system temperature is not exceeded, the bridge alignment is corrected based on the refined analysis model of the large-span dual-purpose steel truss cable-stayed bridge for highway and railway use.

7. The method for controlling the laying alignment of ballastless track for a large-span dual-purpose steel truss cable-stayed bridge for road and rail as claimed in claim 4, characterized in that: The step 6 comprises: First, construct the bridge's ancillary facilities, excluding the tracks. The weight of each type of ancillary facility is then applied step by step. The impact of the different dead loads on the bridge's alignment is monitored using the monitoring system for large-span dual-use steel truss cable-stayed bridges. Cable adjustment targets are calculated based on a refined analysis model for large-span dual-use steel truss cable-stayed bridges, and the bridge deck alignment is corrected using cable adjustment. After the construction of all ancillary facilities on the bridge, excluding the track, was completed, the impact of the second phase of the dead load on the ancillary facilities on the track alignment was calculated and analyzed based on the load and temperature conditions before ballastless track construction, using the refined analysis model for large-span dual-use steel truss cable-stayed bridges for road and rail. Based on the changes in the bridge deck alignment, stiffness corrections were made to the key influencing parameters of the refined analysis model for large-span dual-use steel truss cable-stayed bridges for road and rail. Based on the monitoring system of large-span dual-purpose steel truss cable-stayed bridge for road and railway, and the influence of the stress and deformation of the upper highway bridge surface on the lower railway bridge deck during the construction process in step 3, the theoretical line shape during the laying of ballastless track is predicted.

8. The method for controlling the laying alignment of ballastless track for a large-span dual-purpose steel truss cable-stayed bridge for road and rail according to claim 7, characterized in that: The step 6 further comprises: Combining the deformation envelope curves and monitoring data of the lower railway bridge track alignment under different loads on the railway bridge deck and the highway bridge deck, the linear variation law of the bridge track is analyzed, and the functional relationship between the bridge deformation y, temperature t, and constant load p is established to improve and supplement the bridge deformation under extreme loads that cannot be measured under actual monitoring conditions: y=f(t,p,x) Where x is the horizontal coordinate of the bridge deformation monitoring point.

9. The method for controlling the laying alignment of ballastless track for a large-span dual-purpose steel truss cable-stayed bridge for road and rail according to claim 1, characterized in that: The step 7 comprises: Based on the predicted theoretical alignment during ballastless track laying, the ballastless track on the bridge is constructed sequentially. The adjustability of the track base plate is used to eliminate local alignment errors in the main beam segments. The self-compacting concrete layer is then used to fine-tune the track alignment. Finally, fasteners are used to make sub-millimeter adjustments to the track alignment.

10. A linear control system for laying ballastless track on a large-span dual-purpose steel truss cable-stayed bridge for road and rail, characterized in that: include: Monitoring system construction module: It is used to build a monitoring system for a large-span dual-use steel truss cable-stayed bridge for road and rail to monitor bridge response information and environmental information; Refined Analysis Model Construction Module: This module is used to establish an initial finite element model to simulate the various construction processes of the bridge track. Based on the monitoring system of the large-span dual-use steel truss cable-stayed bridge for road and rail, the parameters of the initial finite element model are modified to establish a refined analysis model for the large-span dual-use steel truss cable-stayed bridge. Analysis module: This module is used to analyze the influence of the upper highway bridge deck on the stress and deformation of the lower railway bridge deck during construction based on the refined analysis model of the large-span dual-purpose steel truss cable-stayed bridge; A CPIII precision measurement network construction module is used to deploy the CPIII precision measurement network and establish a CPIII precision measurement network real-time correction model to correct the CPIII precision measurement network; The beam surface linear correction module is used to correct the beam surface linear shape by adjusting the pre-camber of the bridge to be laid track by adjusting cables before the construction of the track structure and ancillary facilities; Theoretical alignment prediction module: This module is used for the step-by-step construction of other ancillary facilities on the bridge, excluding the track. Based on the monitoring system of a large-span dual-use steel truss cable-stayed bridge for highway and railway use and analysis of the impact of the upper highway bridge deck on the stress and deformation of the lower railway bridge deck during construction, the theoretical alignment during ballastless track laying is predicted. Theoretical alignment construction module: It is used to construct ballastless track on bridges based on the theoretical alignment during ballastless track laying; Linearity acceptance module: used to accept the track laying alignment; The linear control system for laying ballastless track of a large-span dual-purpose steel truss cable-stayed bridge for road and railway is used to execute the steps in the linear control method for laying ballastless track of a large-span dual-purpose steel truss cable-stayed bridge for road and railway as described in any one of claims 1-9.

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