A linear control method for double-block type ballastless track laying of a large-span highway-railway combined steel truss girder cable-stayed bridge

Abstract

The application relates to the technical field of high-speed railway track engineering construction, and provides a double-block type ballastless track laying linear control method for a large-span highway-railway dual-purpose steel truss girder cable-stayed bridge, a refined structure model is established through ANSYS, the whole-system load of the ballastless track is simulated through equivalent loading of the whole domain of the full load of the upper highway bridge deck through water bags, the actual rigidity of the beam body is accurately identified, and the calculation model is corrected; the temperature-displacement deformation law is obtained through periodical wireless intelligent monitoring, track elevation accurate temperature correction is realized; the CPIII measurement network layout scheme is optimized, the problems of measurement point shielding and unstable reference are solved; the construction is carried out in the mode of first edge and then middle, transverse synchronization and symmetrical segmentation, combined with multi-stage linear correction of leveling layers, base plates and track bed plates; track fine adjustment is closed-loop completed in a low-temperature stable period at night, the track bed plate is poured after passing the acceptance, and finally, linear acceptance is completed. The application can preferably perform linear control.

Description

Technical Field

[0001] This invention relates to the field of high-speed railway track engineering construction technology, specifically to a method for controlling the alignment of double-block ballastless track laying in a long-span dual-purpose (railway and highway) steel truss cable-stayed bridge. Background Technology

[0002] Ballastless track has become the mainstream track structure for high-speed and heavy-haul railways due to its advantages such as high smoothness, high stability, high durability, and low maintenance requirements. With the development of high-speed railways, laying ballastless track on long-span bridges with a main span of more than 200m has become an important development trend in the industry in order to further improve train speed, operating comfort, and reduce the total life-cycle maintenance cost.

[0003] The long-span steel truss cable-stayed bridge for both road and rail use has a complex structural system and relatively low overall stiffness, presenting significant technical challenges during the double-block ballastless track laying stage: 1) Extremely high laying accuracy requirements: the allowable deviation of the ballastless track bearing platform elevation is only -8 to +2 mm, and the adjustable range of the track bed slab after pouring is minimal; 2) Significant load impact: the relatively low stiffness of long-span bridges means that secondary dead loads such as track slabs and base plates can cause mid-span deflection of up to -50 mm, making deformation difficult to calculate accurately; 3) Complex structural system transformation: the cable-stayed bridge undergoes tower-beam temporary anchorage, cable tensioning, segmental assembly, and closure. 4) The structure is highly sensitive to environmental factors such as temperature and wind load, which significantly affect the deformation of the cable-beam-tower composite structure and are difficult to calculate accurately. 5) It is difficult to identify the actual stiffness. The structure is composed of a variety of materials and is affected by environmental factors such as temperature and load. The actual stiffness deviates significantly from the theoretical design value. 6) Existing technologies have limitations. Pure theoretical calculation methods lack physical verification, and the mid-span local load stiffness identification method cannot fully simulate the load effect of the entire bridge. Both of these methods are difficult to meet the requirements of high-precision alignment control.

[0004] Existing alignment control technologies are mostly designed for pure railway cable-stayed bridges or CRTSⅢ type slab track ballastless tracks, failing to fully consider the load coupling effect of dual-purpose railway and highway double-layer bridge decks and the construction process characteristics of double-block ballastless tracks. They lack a comprehensive, high-precision, and practical alignment control system. Therefore, there is an urgent need to develop an alignment control method for laying double-block ballastless tracks suitable for large-span dual-purpose railway and highway steel truss cable-stayed bridges, solving the problem of alignment accuracy control and ensuring the safe and stable operation of high-speed railways. Summary of the Invention

[0005] The present invention provides a method for controlling the alignment of double-block ballastless track laying for a long-span steel truss cable-stayed bridge for both road and rail use, which can overcome some or all the defects of the prior art.

[0006] According to the present invention, a method for controlling the alignment of a double-block ballastless track laying for a long-span steel truss cable-stayed bridge for both road and rail use includes the following steps: (1) A refined structural analysis model of a long-span steel truss cable-stayed bridge for both road and rail use was established using ANSYS; (2) Displacement monitoring points and temperature test points were set up on site. A wireless intelligent monitoring system was used to periodically collect and fit the temperature-displacement change curve. The reference temperature was 17.9℃. (3) Water bags are laid on the upper highway bridge deck according to the second phase of the ballastless track system to perform graded preloading of equivalent load with correction coefficients, identify the actual stiffness of the beam and correct the model. (4) After the preloading is completed, the bridge alignment is measured and the cable tension is adjusted to ensure that the alignment and cable tension meet the design requirements; (5) Optimize and densify the CPⅢ precision measurement network to solve the problems of measurement point occlusion and unstable benchmark, and establish a CPⅢ three-dimensional coordinate real-time correction and prediction model; (6) The leveling layer is constructed symmetrically in multiple sections to eliminate residual alignment errors after cable adjustment; (7) The base plate was constructed using the CPⅢ results of the day, and the corresponding water bag load was released simultaneously during the pouring process; (8) After the base plate is completed, the entire bridge alignment is checked and measured; (9) Import the temperature-displacement data into the model and perform temperature correction on the track bed slab elevation; (10) Concentrate equipment and manpower to quickly complete CPⅢ measurement, ensure that the results can be used on the same day, and simultaneously use 4 fine-tuning trolleys to fine-tune the track frame; (11) The track fine-tuning is completed in a closed loop during the night when the temperature is stable and the temperature difference between the cable beams is small. After passing the test, the track bed slab concrete is poured immediately. (12) Complete the track laying alignment acceptance according to the specifications.

[0007] As a preferred option, in step (3), the total weight of the water bags is 9375.4 tons, with a total of 128 bags, which are deployed on the entire bridge deck. The full load preloading is carried out in stages: 50% for the side span, 50% for the middle span, 100% for the side span, and 100% for the middle span. The actual stiffness of the structure is 1.148 times the theoretical value when the temperature is stable in the early morning and the wind speed is ≤5m / s.

[0008] Preferably, in step (4), the deviation of the cable shape after adjustment is controlled within 5mm to -15mm, and the deviation of the cable force is within 0.19% to 3.68%.

[0009] As a preferred option, in step (5), the spacing between CPⅢ points is reduced to a minimum of 48m; CPⅡ points at the main tower are changed to CPⅢ points; and CPⅢ points of the approach bridge are arranged on the stable highway pier.

[0010] As a preferred option, in step (6), the leveling layer is constructed in four sections: tower area, side span area, secondary side span area, and middle span area, with the thickness controlled at 14.5-16.5cm; the base plate and track bed plate are constructed using a process of first the side and then the middle, synchronous laterally, and symmetrical construction of large and small mileage sections.

[0011] As a preferred option, the track bed elevation is dynamically corrected in step (9) using 17.9℃ as the reference temperature.

[0012] As a preferred option, in step (9), for every 1°C increase in temperature, the mid-span elevation decreases by a maximum of 1.58 mm.

[0013] As a preferred option, the maximum deformation caused by the temperature difference of the cable beam in step (11) is 10mm, and the range of influence is 130m. Fine-tuning should be completed during the low temperature and small temperature difference period at night. If it is not completed, fine-tuning should be re-measured and re-adjusted the next day.

[0014] The beneficial effects of this invention are as follows: 1) Reliable stiffness identification: The full-load equivalent preloading simulation of the second-stage dead load significantly improves the accuracy of beam stiffness identification compared to pure theoretical calculation and local ballast, and the line prediction is more in line with the site.

[0015] 2) Precise and efficient temperature correction: Regular monitoring establishes temperature-displacement curves to achieve dynamic correction of track elevation, effectively eliminating elevation deviations caused by temperature effects.

[0016] 3) Stable and controllable measurement benchmark: CPIII rapid measurement and same-day closed-loop use completely avoid the influence of ambient temperature and beam deformation on the measurement results, and the benchmark error is finely adjusted to ≤1mm.

[0017] 4) Gradual refinement of alignment control: Through a four-stage control system of cable adjustment (centimeter level), leveling layer (millimeter level), base plate correction (millimeter level), and track bed fine adjustment (sub-millimeter level), it is fully adapted to the small adjustable range characteristics of double-block ballastless track.

[0018] 5) Strong engineering applicability: It is specifically designed for large-span dual-purpose steel truss cable-stayed bridges for both road and rail and double-block ballastless track, and can directly guide the construction of similar projects, filling the technical gap. Attached Figure Description

[0019] Figure 1 This is a flowchart illustrating a method for controlling the alignment of a double-block ballastless track laying for a long-span steel truss cable-stayed bridge used for both road and rail transport, as described in the embodiment. Figure 2 This is a reference schematic diagram for establishing the structure and finite element model of the actual engineering long-span bridge-ballastless track system in the embodiment; Figure 3 This is a comparison diagram of the theoretical alignment obtained from finite element calculations and the vertical deformation of the bridge in actual engineering. Figure 4 This is a schematic diagram of the planar arrangement of CPIII and temperature-displacement sensors on the bridge in the embodiment; Figure 5 This is a schematic diagram of the temperature-displacement relationship curve plotted using sensor data in the embodiment. Figure 6 This is a transverse layout diagram of the upper highway bridge deck with water bags arranged according to the second-phase dead load equivalent of the ballastless track system in the embodiment. Figure 7 This is a longitudinal schematic diagram of the upper highway bridge deck with water bags arranged according to the second-phase dead load equivalent of the ballastless track system in the embodiment. Figure 8 This is a comparison diagram of the alignment under the example where the simulated alignment of the water bag construction on the upper bridge deck is 1:1 with the actual dead load ratio of the lower bridge deck; Figure 9 This is a comparison diagram of the simulated alignment of the upper bridge deck water bag construction and the alignment of the lower bridge deck after adjustment by correction factors, as shown in the example. Figure 10 This is a schematic diagram of the rail frame assembly during the track fine-tuning construction in the embodiment. Detailed Implementation

[0020] To further understand the content of this invention, a detailed description of the invention will be provided in conjunction with the accompanying drawings and embodiments. It should be understood that the embodiments are merely illustrative and not limiting of the invention.

[0021] Example like Figure 1 As shown, this embodiment provides a method for controlling the alignment of double-block ballastless track laying for a long-span dual-purpose (railway and highway) steel truss cable-stayed bridge. Addressing the construction challenges of double-block ballastless track for a 320m-class combined rail and highway harp-shaped cable-stayed bridge, this method achieves controllable alignment and meets accuracy standards throughout the entire double-block ballastless track laying process by employing full-load equivalent loading to accurately identify actual stiffness, periodic temperature and displacement monitoring, CPⅢ measurement network optimization, multi-segment symmetrical segmented construction, and multi-stage progressive alignment correction. This satisfies the construction and acceptance standards for high-speed railway ballastless track. Specifically, the method includes the following steps: (1) A refined structural analysis model of a long-span steel truss cable-stayed bridge for both road and rail use was established using ANSYS; Using ANSYS finite element software, based on the design parameters of the piers, main beams, towers, and stay cables, such as... Figure 2 As shown, a full-parameter structural analysis model was established, and the finite element bridge alignment was adjusted based on the cable force parameters before and after bridge completion. Simulation calculations were performed on the stress, deformation, and system transformation at each stage of track construction to form a theoretical alignment benchmark and deformation prediction curve. A comparison between the theoretical alignment obtained from the finite element model and the actual bridge deformation is shown in the figure. Figure 3 .

[0022] (2) Displacement monitoring points and temperature test points were set up on site. A wireless intelligent monitoring system was used to periodically collect and fit the temperature-displacement change curve. The reference temperature was 17.9℃. Temperature-displacement sensors are installed on the top of the steel guardrails on the lower layer of the steel beam bridge deck. The sensor layout is shown in the diagram. Figure 4 The bridge spacing is 20m along the longitudinal direction; a wireless intelligent monitoring system is used to continuously collect real-time temperature and displacement data for no less than 30 days. After removing outliers, a temperature-displacement curve is simulated, and a database of beam temperature deformation patterns is established. The temperature-displacement relationship curve obtained from the sensor data is shown in the figure. Figure 5 As shown.

[0023] (3) Water bags are installed on the upper highway bridge deck according to the second-phase dead load equivalent arrangement of the ballastless track system. The longitudinal and transverse schematic diagrams of the water bag arrangement are shown below. Figure 6 and Figure 7 As shown, equivalent load grading preloading with correction coefficients is performed to identify the actual stiffness of the beam and correct the model. The total value and distribution of the second-phase dead load, including the ballastless track base plate, track bed slab, rail fasteners, and bridge deck accessories, were accurately calculated. The calculated total weight of the second-phase dead load was 8745.7t, which served as the basis for the equivalent load of the uniformly distributed water bag. If a 1:1 water bag load is used to simulate the actual dead load, the comparison between the uncorrected simulated alignment of the upper bridge deck and the actual dead load of the lower bridge deck is as follows: Figure 8 As shown, considering the difference between the water bag load on the upper bridge deck and the actual dead load on the lower deck, correction coefficients for the side spans, secondary side spans, and main spans are calculated using a finite element model. The second-phase dead load is converted into a uniformly distributed water bag load, and correction coefficients for the side spans are calculated using a finite element model. The correction coefficients for the secondary side span and the main span are: After correction by the correction factor, the preloading alignment of the upper bridge deck and the alignment of the lower bridge deck with the applied secondary load are compared. Figure 9 As shown, 128 water bags were therefore deployed across the entire upper highway bridge deck, with a total weight of 9375.4 tons. The total weight of the water bags in the side spans was 616 tons, the total weight of the water bags in the secondary side spans was 4149.2 tons, and the total weight of the water bags in the main spans was 4610.2 tons. The water bags were applied in stages: 50% for the side spans, 50% for the middle spans, 100% for the side spans, and 100% for the middle spans.

[0024] The beam deformation was measured during the early morning period when the temperature was stable and the wind speed was ≤5m / s. The calculated actual stiffness of the dual-purpose railway and highway steel truss girder was 1.148 times the theoretical value, indicating that the actual overall stiffness of the bridge was greater than the design expectation. After accurately identifying the actual stiffness, the calculation of the mid-span deflection caused by the second-phase dead load was more accurate, providing a reliable benchmark for cable adjustment, leveling, and track fine-tuning, and the finite element model parameters were corrected accordingly.

[0025] (4) After the preloading is completed, the bridge alignment is measured and the cable tension is adjusted to ensure that the alignment and cable tension meet the design requirements; After the full load preloading is completed, the actual alignment of the bridge is measured using a precision level and total station. With the design alignment and design cable force as control targets, the cable force of the stay cables is precisely adjusted so that the deviation of the actual alignment of the bridge is controlled within 5mm to -15mm and the deviation of cable force is within 0.19% to 3.68%, thus completing the initial locking of the bridge alignment.

[0026] (5) Optimize and densify the CPⅢ precision measurement network to solve the problems of measurement point occlusion and unstable benchmark, and establish a CPⅢ three-dimensional coordinate real-time correction and prediction model; To address the issues of excessively large spacing between conventional CPⅢ grids, obstruction of measuring points on the main tower, and inability to install measuring points on the movable supports of approach bridges, the following principles should be followed: To address the issues of excessively large spacing in conventional CPⅢ networks, obstruction of measuring points on the main tower, and the inability to install measuring points on the movable supports of the approach bridges, CPⅢ points on the main bridge section are located on the top of the lower bridge deck retaining wall, with a spacing increased to 48–53.3 m. CPⅡ points at the main tower are replaced with CPⅢ points, and CPⅢ points on the approach bridges are located on the stable highway piers. Point pairs are preferentially placed above fixed supports, with spacing increased to 1 / 3, 1 / 2, and 2 / 3 within the span of movable supports and large-span steel beams. Points are placed separately on the inner side of the main tower, and when obstructed by highway piers, they are placed on the side of the pier. Steel beams are fixed by welding. A total of 20 pairs of CPⅢ points are deployed across the entire bridge, covering the tower area, mid-span, and closure section. Point pairs are set up in pairs along both sides of the line, with a mileage difference ≤1 m, an elevation at least 0.3 m above the track surface, and a point pair spacing of 50–70 m, not exceeding 80 m in large-span sections. Each point is observed by at least 3 free measuring stations, with a station spacing of approximately 120 m and a maximum observation distance ≤180 m.

[0027] Compared to the CPⅢ network, the CPⅢ measurements for long-span cable-stayed bridges are not limited to fixed supports. Some points deform significantly with temperature and load, resulting in time-sensitive data. Measurements must be taken immediately at night when temperatures are low and the temperature difference between cables and beams is small, and a temperature-displacement correction model must be established. Due to the obstruction of the upper bridge deck, the CPⅡ densification uses a traverse network method, with elevations transferred through two independent sets of trigonometric leveling stations at intermediate stations. The remeasurement frequency is much higher than in conventional sections, requiring dynamic remeasurement before and after cable adjustments, load changes, and construction of each structural layer, and must be linked to the bridge alignment monitoring system.

[0028] After optimization, a three-dimensional coordinate real-time correction model was established in the bridge axis coordinate system, based on real-time bridge deformation, temperature field, and wind speed monitoring data, to correct the coordinates of each CPⅢ control point.

[0029] (6) The leveling layer is constructed symmetrically in multiple sections to eliminate residual alignment errors after cable adjustment; The leveling layer is constructed in four sections: tower area, side span area, secondary side span area, and middle span area. The leveling layer is constructed in accordance with the principles of side first and then middle, horizontal synchronization, and symmetry of large and small mileage. The design thickness of the leveling layer is 15cm, and the actual thickness is controlled at 14.5-16.5cm to eliminate residual alignment errors after cable adjustment.

[0030] (7) The base plate was constructed using the CPⅢ results of the day, and the corresponding water bag load was released simultaneously during the pouring process; The base plate layout and construction were carried out using CPⅢ results that were measured and valid on the same day. The base plate was divided into three sections: tower area, side span area, and middle span area. The side span was poured first, followed by the middle span, with the left and right lines poured simultaneously and in sections with symmetrical pouring. During the pouring process, the water bag loads of the corresponding sections were released in stages. The released load values ​​were equal to the load values ​​of the base plate, so that the stress state of the bridge was matched with the construction progress in real time.

[0031] (8) After the base plate is completed, the entire bridge alignment is checked and measured; After the concrete of the base plate has been cured to the required standard, the elevation, centerline, and alignment of the entire bridge are comprehensively remeasured. The deviation between the theoretical alignment and the actual alignment is compared, and an alignment verification report is generated to provide a measured control benchmark for the construction of the track bed slab.

[0032] (9) Import the temperature-displacement data into the model and perform temperature correction on the track bed slab elevation; The previously collected temperature and displacement monitoring data were imported into the corrected structural analysis model. Using 17.9℃ as the baseline temperature, for every 1℃ increase in temperature, the mid-span elevation decreased by a maximum of approximately 1.58mm. After the steel beam closure, bridge deck facilities were removed, and the load stabilized, continuous monitoring was conducted for 15 days, measuring the temperature and longitudinal displacement of the steel beam cross-section. After removing outlier data, a temperature... With deformation linear regression equation The reference temperature correction factor is obtained. Before laying the ballastless track, for more than 7 consecutive days, during the early morning hours when the temperature is uniform, there is no solar radiation gradient, and there is no construction interference, i.e., from 2:00 to 4:00 AM, the overall temperature and longitudinal displacement of the steel beams were measured simultaneously, and the temperature difference between the early morning hours of two adjacent days was calculated. With displacement difference Seeking it day by day The average value is taken as the pure temperature scaling correction factor. .contrast and If the deviation between the two is ≤5%, take the average value. This serves as the final temperature correction factor; if the deviation exceeds 5%, the cause is analyzed and supplementary observations are conducted before recalculation. After calculating the correction values ​​for the track bed slab construction elevation under different temperature conditions, the ambient temperature and steel beam temperature are measured in real time during on-site construction, and the actual construction elevation of the track bed slab is dynamically corrected according to the correction curve.

[0033] (10) Concentrate equipment and manpower to quickly complete CPⅢ measurement, ensure that the results can be used on the same day, and simultaneously use 4 fine-tuning trolleys to fine-tune the track frame; Four or more total stations and a sufficient number of surveyors were deployed to quickly complete the CPⅢ full network resurvey, ensuring the results were usable on the same day. Simultaneously, four fine-tuning trolleys were configured to operate in parallel, performing high-precision fine-tuning of the track panels. During the track fine-tuning construction, the track panel assembly... Figure 10 As shown. This step ensures that the measurement benchmark is valid on the same day, and that fine-tuning and construction are synchronized, avoiding time-related errors caused by time delays or environmental changes, and significantly improving fine-tuning efficiency and track panel positioning accuracy.

[0034] (11) The track fine-tuning is completed in a closed loop during the night when the temperature is stable and the temperature difference between the cable beams is small. After passing the test, the track bed slab concrete is poured immediately. Temperature differences in the cable-stayed bridge can cause a maximum deformation of 10mm, affecting an area of ​​approximately 130m. Track fine-tuning must be strictly completed at night when temperatures are stable and the temperature difference between the cable-stayed bridge and the bridge is minimal. If fine-tuning is not completed before the temperature rises, CPⅢ measurements will be taken again the following night, and fine-tuning will be based on the new results. This nighttime low-temperature closed-loop fine-tuning effectively eliminates the accumulation of track deformation caused by temperature differences, ensuring the alignment is formed in one go and avoiding rework due to exceeding tolerances caused by temperature rises. Ultimately, it meets the smoothness acceptance standards for 350km / h high-speed railways. After the track fine-tuning meets the requirements of a track support elevation of -8 to +2mm and a centerline deviation of ≤2mm, the ballast slab concrete pouring will proceed immediately.

[0035] (12) Complete the track laying alignment acceptance according to the specifications.

[0036] According to the "High-speed Railway Track Engineering Construction Quality Acceptance Standard", the smoothness of the 60m long-wave and 10m short-wave tracks, the elevation of the track support platform, the centerline deviation, and the TQI dynamic index are tested and accepted to ensure that the track shape meets the design and specification requirements.

[0037] This embodiment was successfully applied to the main bridge of the west branch of the Ganjiang Railway-Highway Bridge on the Changjiu High-speed Railway. The maximum deviation of the track alignment after the construction of the base plate was -6.5mm, and the maximum deviation of the track alignment after the construction of the track bed plate was -5.5mm, both of which are far less than the allowable deviation of -8 to +2mm. This achieved high-precision alignment control of the double-block ballastless track of a long-span railway-highway combined cable-stayed bridge, verifying the scientific nature and effectiveness of this method.

[0038] The key control points are as follows: 1) Strictly control the accuracy of the closure alignment, and do a good job of monitoring the lateral, elevation, torsional alignment and cable tension before closure; 2) Dynamically monitor the alignment and cable tension throughout the entire construction process, and analyze and correct them in a timely manner; 3) Ensure the accuracy of equivalent load loading, strengthen the metering control of water bag loading and unloading, and optimize water bag leakage prevention measures; 4) Adhere to the principle of prioritizing the sides before the middle, simultaneous lateral construction, and symmetrical construction to reduce the adverse effects of asymmetrical loading on the alignment; 5) Strengthen the management of temperature-sensitive periods. Prioritize the construction of ballastless track during periods when the nighttime temperature is stable and the temperature difference between the cable beams is small.

[0039] The present invention and its embodiments have been described above illustratively. This description is not restrictive, and the figures shown are only one embodiment of the present invention; the actual structure is not limited thereto. Therefore, if those skilled in the art are inspired by this description and design similar structures and embodiments without departing from the spirit of the present invention, such designs should fall within the protection scope of the present invention.

Claims

1. A method for controlling the alignment of a double-block ballastless track laying for a long-span dual-purpose (road and rail) steel truss cable-stayed bridge, characterized in that: Includes the following steps: (1) A refined structural analysis model of a long-span steel truss cable-stayed bridge for both road and rail use was established using ANSYS; (2) Displacement monitoring points and temperature test points were set up on site. A wireless intelligent monitoring system was used to periodically collect and fit the temperature-displacement change curve. The reference temperature was 17.9℃. (3) Water bags are laid on the upper highway bridge deck according to the second phase of the ballastless track system to perform graded preloading of equivalent load with correction coefficients, identify the actual stiffness of the beam and correct the model. (4) After the preloading is completed, the bridge alignment is measured and the cable tension is adjusted to ensure that the alignment and cable tension meet the design requirements; (5) Optimize and densify the CPⅢ precision measurement network to solve the problems of measurement point occlusion and unstable benchmark, and establish a CPⅢ three-dimensional coordinate real-time correction and prediction model; (6) The leveling layer is constructed symmetrically in multiple sections to eliminate residual alignment errors after cable adjustment; (7) The base plate was constructed using the CPⅢ results of the day, and the corresponding water bag load was released simultaneously during the pouring process; (8) After the base plate is completed, the entire bridge alignment is checked and measured; (9) Import the temperature-displacement data into the model and perform temperature correction on the track bed slab elevation; (10) Concentrate equipment and manpower to quickly complete CPⅢ measurement, ensure that the results can be used on the same day, and simultaneously use 4 fine-tuning trolleys to fine-tune the track frame; (11) The track fine-tuning is completed in a closed loop during the night when the temperature is stable and the temperature difference between the cable beams is small. After passing the test, the track bed slab concrete is poured immediately. (12) Complete the track laying alignment acceptance according to the specifications.

2. The method for controlling the alignment of double-block ballastless track laying for a long-span dual-purpose steel truss cable-stayed bridge according to claim 1, characterized in that, In step (3), the total weight of the water bags is 9375.4 tons, with a total of 128 bags, which are deployed on the entire bridge deck. The full load preloading is carried out in stages: 50% for the side span, 50% for the middle span, 100% for the side span, and 100% for the middle span. The actual stiffness of the structure is 1.148 times the theoretical value when the temperature is stable in the early morning and the wind speed is ≤5m / s.

3. The method for controlling the alignment of double-block ballastless track laying for a long-span dual-purpose steel truss cable-stayed bridge according to claim 2, characterized in that, In step (4), the deviation of the cable shape after adjustment is controlled within 5mm to -15mm, and the deviation of the cable force is within 0.19% to 3.68%.

4. The method for controlling the alignment of double-block ballastless track laying for a long-span dual-purpose steel truss cable-stayed bridge according to claim 3, characterized in that, In step (5), the spacing between CPⅢ points is reduced to a minimum of 48m; CPⅡ points at the main tower are changed to CPⅢ points; and CPⅢ points on the approach bridge are set on the stable highway piers.

5. The method for controlling the alignment of double-block ballastless track laying for a long-span dual-purpose steel truss cable-stayed bridge according to claim 4, characterized in that, In step (6), the leveling layer is constructed in four sections: tower area, side span area, secondary side span area, and middle span area, with the thickness controlled at 14.5-16.5cm; the base plate and track bed plate are constructed using a process of first the side and then the middle, synchronous laterally, and symmetrical construction of large and small mileage.

6. The method for controlling the alignment of double-block ballastless track laying for a long-span dual-purpose steel truss cable-stayed bridge according to claim 5, characterized in that, In step (9), the track bed elevation is dynamically corrected using 17.9℃ as the reference temperature.

7. The method for controlling the alignment of double-block ballastless track laying for a long-span dual-purpose steel truss cable-stayed bridge according to claim 6, characterized in that, In step (9), for every 1°C increase in temperature, the mid-span elevation decreases by a maximum of 1.58 mm.

8. The method for controlling the alignment of double-block ballastless track laying for a long-span dual-purpose steel truss cable-stayed bridge according to claim 7, characterized in that, In step (11), the temperature difference of the cable beam causes a maximum deformation of 10 mm and an influence range of 130 m. Fine adjustment must be completed during the low temperature and small temperature difference period at night. If it is not completed, the fine adjustment should be remeasured and adjusted the next day.

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