Elevation-adjustable transition section structure and elevation adjustment method therefor

Abstract

An elevation-adjustable high-speed railway roadbed transition section structure. By arranging jacks below an approach slab, jacking of the approach slab enables a rail top surface elevation in an approach slab range to vary linearly, and then grouting is carried out in a gap between the approach slab and a roadbed to eliminate a void. On one hand, the present invention greatly improves the stress condition of the approach slab, and improves the driving safety, and on the other hand, the linearly varying rail top surface elevation can also improve the line smoothness, and improves the driving comfort.

Description

A transition section structure with adjustable elevation and elevation adjustment method thereof Technical Field

[0001] The invention relates to an experimental device, in particular to a transition section structure with adjustable elevation and an elevation adjustment method thereof. Background Art

[0002] To prevent post-construction differential settlement at the junction of the abutment and the transition section roadbed from causing train bouncing, a slatted plate is typically installed. However, within a certain range behind the abutment, the slatted plate inevitably becomes detached from the underlying roadbed soil. This detachment leaves the middle portion of the slatted plate hanging in the air, exacerbating stress conditions, increasing bending, and amplifying dynamic response during train passage, compromising driving safety and comfort.

[0003] A liftable pier slab (Ma Chifan, Wang Shengyuan. Liftable abutment pier slab to deal with bridgehead vehicle jumps [J]. Guangdong Highway Traffic, 2001(03):38-39.) was proposed to solve the bridgehead vehicle jump problem. The liftable pier slab must reserve a working well under the bolster. The wall of the working well is made of prefabricated slabs, and a 30cm thick concrete foundation is set at the bottom of the well. The space of the working well fully considers the need to place jacks and perform operations, and is usually filled with sand. When the pier slab needs to be lifted, the sand in the working well is taken out, and a pedestal jack is placed to lift the bolster and pier slab, and then cement slurry is pressed under the slab from the reserved hole or the side of the slab.

[0004] The practice of installing corbels in the middle and ends of the aforementioned liftable scaffolding is unreasonable. This is because installing the corbels causes stress concentration in the soil near them, resulting in excessive settlement at the corbels. Furthermore, the corbels increase the lateral bending stiffness of the scaffolding, but when the soil beneath the scaffolding is hard and dense, the corbels' lateral bending effect is insignificant. A 30cm-thick concrete foundation at the bottom of the working pit provides support and prevents it from sinking. However, under the cyclic loads of the vehicle, the soil surrounding the working pit settles relative to the pit, causing the pit walls to protrude. The scaffolding is supported only by the walls, deteriorating its load-bearing condition.

[0005] Summary of the Invention

[0006] In order to solve the defects in the prior art, the present invention discloses a high-speed railway roadbed transition section structure with adjustable elevation, and its technical solution is as follows:

[0007] A high-speed railway subgrade transition section structure with adjustable elevation is characterized by: jacks are set under the slab to lift the slab so that the elevation of the rails within the slab changes linearly, and then grouting is performed in the gap between the slab and the subgrade to eliminate voids.

[0008] Based on the above experimental device, the present invention also discloses a method for constructing a high-speed railway roadbed transition section with adjustable elevation, which is characterized by comprising the following steps:

[0009] Step 1: Bury the jack working slot;

[0010] Step 2: Measure the elevation of the rail top surface before jacking and determine the target elevation of the rail top surface at the jack during jacking;

[0011] Step 3: Chisel away the sealing layer and excavate graded gravel;

[0012] Step 4: Install the jack to realize the lifting operation;

[0013] Step 5: Grouting operation;

[0014] Step 6: After the mortar strength reaches the design requirements, the jack releases the pressure and allows the slab to fall back onto the solidified mortar layer;

[0015] Step 7: Re-measure the centerline and elevation of the rail top surface;

[0016] Step 8: Based on the re-measurement results of the rail top centerline and elevation in Step 7, adjust the fasteners and tighten them in time, and perform preliminary fine-tuning of the line;

[0017] Step 9: Repair the sealer. Beneficial effects

[0018] Lifting the tread causes the elevation of the rail top surface within the tread range to change linearly, and then grouting is performed in the gap between the tread and the roadbed to eliminate the voids. On the one hand, the originally bent and deformed tread is restored to straightness, which greatly improves the stress condition of the tread and enhances driving safety. On the other hand, the linearly changing elevation of the rail top surface can also improve the smoothness of the line and enhance riding comfort. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] FIG1 is a schematic diagram of the distribution of the working slots of the jack of the present invention;

[0020] FIG2 is a schematic diagram of a slab according to the present invention;

[0021] FIG3 is a graph showing the settlement curve of the rail top surface according to the present invention;

[0022] FIG4 is a schematic diagram of the excavation graded crushed stone structure of the present invention;

[0023] FIG5 is a schematic diagram of the process of the present invention. DETAILED DESCRIPTION

[0024] A high-speed railway subgrade transition section structure with adjustable elevation features: by arranging jacks at appropriate positions below the slab, the slab is lifted so that the rail elevation within the slab changes linearly; then, grouting is performed in the gap between the slab and the subgrade to eliminate gaps. This significantly improves the stress condition of the slab and enhances driving safety; and the linearly varying rail elevation also improves line smoothness and enhances driving comfort.

[0025] Based on the above-mentioned elevation-adjustable high-speed railway roadbed transition section structure, the present invention discloses a method for an elevation-adjustable high-speed railway roadbed transition section structure, comprising the following steps:

[0026] Step 1: Burying the jack working slot

[0027] As shown in Figure 1, the slab is 10m long after the abutment is removed and extends 0.8m into the abutment, resulting in a total slab length of 10.8m. Based on the slab length, the slab thickness is determined to be 0.4m. The slab is located below the base plate. In the subgrade section, the base plate of the CRTS III slab track is 3.1m wide. If the slab width is 4.1m, the slab extends 0.5m beyond the base plate on both sides. Jack working trenches are embedded below this 0.5m gap. Even if the fill within the jack working trenches cannot provide solid support for the slab, the fill within the 3.1m radius below the base plate still provides solid support.

[0028] Figure 1 shows that the decking is 4.1m wide and 10.8m long, extending 0.8m into the abutment. Also visible are the number and distribution of the jacking slots, which are square in shape, with outer walls measuring 0.7m, 0.04m thick, and 0.3m high.

[0029] If three rows of jack working slots are evenly arranged within the 10m trestle behind the platform, the distance between adjacent rows of jack working slots will be 4.65m, which is larger than the 3.7m distance between two horizontal jack working slots, making this unreasonable. Therefore, the number of jack working slots arranged within the 10m trestle behind the platform must exceed three. If five rows of jack working slots are arranged within the 10m trestle behind the platform, the distance between adjacent rows of jack working slots will be 2.33m or 2.32m, which is far smaller than the 3.7m distance between two horizontal jack working slots. Five rows of jacks, spaced 2.33m or 2.32m apart, provide sufficient support for the trestle.

[0030] The weight of each part of the 10.8m slab and track system is:

[0031] Rail: 0.6kN / m × 10.8m × 2 = 12.96kN

[0032] Track plate: 10.8m×2.5m×0.21m×25kN / m³=141.75kN

[0033] Self-compacting concrete layer: 10.8m×2.5m×0.1m×25kN / m3=67.5kN

[0034] Base plate: 10.8m × 3.1m × 0.3m × 25kN / m³ = 251.1kN

[0035] Plate: 10.8m×4.1m×0.4m×25kN / m3=442.8kN

[0036] Total weight: 12.96 + 141.75 + 67.5 + 251.1 + 442.8 = 916.11 kN

[0037] Therefore, for 10 jacks, each jack needs to provide an average lifting force of 91.611 kN.

[0038] The weight of the crushed stone mixed with 3% cement below the working tank of the jack is 24kN / m 3 , the standard value of cohesion is 55kPa, the standard value of internal friction angle is 32°, then the bearing capacity coefficient is M b =2.6,M d =6.35,M c =8.55, the bearing capacity characteristic value of graded crushed stone with 3% cement is

[0039] fa=2.6×24×b+0+8.55×55

[0040] Where b is the side length of the jack base.

[0041] There are 10 jacks, and each jack needs to provide an average lifting force of 91.611 kN. Accordingly, each jack base exerts an average pressure of 91.611 kN on the crushed stone mixed with 3% cement. Considering that the actual pressure exerted by the jack base on the crushed stone mixed with 3% cement is 91.611 × 2 = 183.222 kN, and this pressure is an axial load, then

[0042] The solution is: b ≥ 0.6m

[0043] Therefore, the side length of the jack base is 0.6m. Considering the convenience of placing the jack base, the inner wall size of the jack working tank is 0.62m×0.62m.

[0044] The standard value of cohesion of 3% cement graded crushed stone around the jack working groove is 55kPa, and the standard value of internal friction angle is 32°. Then the active earth pressure coefficient of 3% cement graded crushed stone is

[0045] According to the "High-Speed ​​Railway Design Code" (TB 10621-2014), the self-weight uniform load of CRTS III slab track is 13.7 kPa, the train uniform load is 40.4 kPa, and the self-weight uniform load of the slab is 10 kPa. Therefore, the total uniform load is 64.1 kPa, which acts on the surface of the 3% cement-graded crushed stone around the jack working trough. Assuming the jack working trough is 0.3 m high, the active earth pressure at the bottom of the jack working trough is

[0046] Therefore, the four walls of the jack working trough are not subjected to the horizontal earth pressure of the 3% cement graded crushed stone. The wall thickness of the jack working trough can be 4 cm, so the outer wall size of the jack working trough is 70 cm × 70 cm.

[0047] When constructing the transition section, a jack working groove is embedded at the position shown in Figure 1. The jack working groove is square, with an outer wall size of 70cm×70cm, a wall thickness of 4cm, and a height of 30cm. One side of the jack working groove is located outside the range of the board and can be removed to facilitate the placement and removal of the jack during jacking operations. It is usually filled and compacted with graded gravel.

[0048] Step 2: Measure the rail top elevation before lifting and determine the target rail top elevation at the jack during lifting

[0049] Figure 2 shows a schematic diagram of the abutment, trestle, and base plate. The circled area represents the rail sleepers above the trestle extending into the abutment. If the jacks at the end of the trestle were to be lifted, they would lift the base plate outside the trestle's range, separating it from the roadbed. Therefore, the jacks at the end of the trestle cannot be lifted, and the settlement of the rail top surface in that area remains unchanged. The main function of the jacks at the end of the trestle is that when the trestle transitions from lying flat on the roadbed to being supported by ten jacks, the jacks at the end of the trestle provide a certain amount of lifting force to maintain the settlement of the rail top surface in that area.

[0050] The circle in Figure 2 is the sleeper above the part of the trestle extending into the abutment. If the settlement of the top surface of the rail at this location decreases during jacking, it means that the part of the trestle extending into the abutment has been lifted, and its bottom surface is separated from the abutment. This is not allowed. Therefore, the settlement of the top surface of the rail at this location should remain unchanged during jacking.

[0051] From the above analysis, it can be seen that the settlement of the rail top surface at the jack at the end of the trestle and the sleeper above the part of the trestle extending into the abutment should remain unchanged during jacking. Therefore, the coordinates of these two locations and the settlement of the rail top surface are used to determine a line segment as the target settlement line segment of the rail top surface within the trestle range. The target settlement of the jacks at the other four locations is determined by interpolation based on their coordinates (as shown in Figure 3). The difference between the target settlement and the actual settlement is the jacking amount.

[0052] As shown in Figure 3, the curve symbolized by the hollow circle shows the actual settlement of the rail top surface before the tack is raised, the curve symbolized by the hollow triangle shows the target settlement of the rail top surface within the tack range obtained before the tack is raised, and the hollow square shows the target settlement of the rail top surface corresponding to the jack.

[0053] Step 3: Chisel away the sealing layer and excavate graded gravel

[0054] As shown in Figure 4, 900 represents the 0.9m-wide section of graded crushed stone between the two cladding boards, requiring excavation to a depth of 0.7m to the bottom of the jack working trench. 1370 in the figure represents 1.37m from the outside of the cladding boards, and 720 in the figure represents 0.72m from the outside of the cladding boards. Together, these two represent excavation from the roadbed surface 1.37m from the outside of the cladding boards downward inward to the bottom of the jack working trench 0.72m from the outside of the cladding boards.

[0055] After chiseling out the closed layer between the lines, excavate 0.70m thick graded gravel within a 0.90m wide range between the two scaffoldings to the bottom of the jack working groove; after chiseling out the closed layer within 1.37m from the outside of the scaffoldings on both sides of the shoulder, excavate 0.70m thick graded gravel downward and inward along the 45° plane to the bottom of the jack working groove.

[0056] Step 4: Install the jack and lift the vehicle

[0057] ① Remove the outer side of the jack working groove, remove the graded gravel in the groove, clean and clean the bottom surface of the board in the center of the groove top, clean the bottom of the groove and level it with medium-coarse sand, and then put in a square wooden pad with a side length of 0.60m.

[0058] ② Place the jack in the center of the wooden pad, connect the cables correctly, and after powering on, perform a pressure-increasing and pressure-relieving action on the jack to ensure that it is working properly. Clean the lifting surface of the jack and slowly apply pressure until the lifting surface is in close contact with the bottom surface of the slats, then stop applying pressure.

[0059] ③ If the jacks cannot be lifted synchronously, one or more jacks will bear a greater lifting force, and the slats will also generate excessive internal forces at the jacks. Therefore, the jacks should be lifted synchronously. However, the lifting capacity of each jack is different, which requires different lifting rates for each jack. After setting the lifting time and the lifting rate of each jack, start synchronous jacking. During the lifting process, it is necessary to closely observe the jacking section and the track structure before and after it. If cracks or bulges are found in the track structure, jacking should be stopped immediately. Jacking can only be continued after the cause is identified, a solution is proposed, and the problem is solved.

[0060] ④ After the synchronous jacking is completed, re-measure the elevation of the rail top surface. If it does not reach or exceeds the target elevation of the rail top surface, it is necessary to adjust the jacking amount until it reaches the target elevation and then lock the jack.

[0061] Step 5: Grouting

[0062] ①Sealing

[0063] After the slab is lifted, gaps will appear between the sides of the slab and the roadbed, and between the bottom of the slab and the top of the jacking trough. To prevent slurry from leaking through these gaps, the slab is sealed with a quick-setting material. An air outlet pipe (a transparent rubber hose) is installed at an appropriate location to accommodate the gap. The air outlet pipe should be exposed 10 cm and plugged immediately when the slurry is full.

[0064] ② Grouting

[0065] Determine the optimal water-to-cement ratio based on site temperature and humidity, as well as prior experience. Add water to the grout and stir until it is evenly mixed, fluid, and free of water seepage. Use drinking water standards and mechanical agitation for 3-5 minutes.

[0066] Apply appropriate pressure during grouting. After the main pipe connects to the shoulder, grouting should be carried out simultaneously in multiple branches to prevent blockage and a sudden increase in grouting pressure caused by a full pipe. After grouting is completed, observe the grouting holes for slurry seepage to determine whether the gaps under the cladding are fully filled. If not, add grouting.

[0067] ③Seal the grouting hole

[0068] After the slab jacking section line meets the requirements after re-measurement, the grouting holes should be sealed with quick-setting micro-expansion mortar with a strength grade of not less than M40.

[0069] Step 6: Drop the board

[0070] After the mortar strength reaches the design requirements, the jack releases the pressure, allowing the scaffolding to fall back onto the solidified mortar layer.

[0071] Step 7: Re-measure the centerline and elevation of the rail top surface

[0072] After the rail slab is dropped, the centerline and elevation of the rail top surface must be remeasured. This not only assesses the effectiveness of the jacking and grouting, but also prepares for the next stage of fine-tuning the track. The actual jacking amount must be verified to ensure it matches the planned amount. Any discrepancies must be addressed, such as by adjusting fasteners, to ensure a smooth rail surface.

[0073] Step 8: Circuit Fine-tuning

[0074] Based on the re-measurement results of the rail top centerline and elevation in the previous step, adjust the fasteners and tighten them promptly. At the same time, perform preliminary fine-tuning of the track.

[0075] Step 9: Repair the Sealing Layer

[0076] The excavated graded gravel is backfilled and compacted, followed by a concrete seal. If this is not completed due to insufficient time, the exposed graded gravel layer should be covered to prevent gravel and soil particles from being swept up by the air currents generated by high-speed trains and hitting the train, potentially causing an accident.

[0077] The core steps of the above steps are jacking up the slab and grouting. Before jacking up the slab, the rail top elevation must be measured to determine the target rail top elevation at each jack. The sealing layer is then chiseled out and graded gravel excavated. During the earlier construction of the road-bridge transition section, jack working grooves were pre-buried. After grouting, the slab is removed after the slurry solidifies. The rail top centerline and elevation are then re-measured, the alignment is fine-tuned, and finally the graded gravel is adjusted back to repair the sealing layer. Each step is logically linked and indispensable, and the order cannot be changed.

[0078] The present invention pre-buries a jack working groove at an appropriate position under the scaffolding. When the scaffolding needs to be treated, a jack is placed in the working groove to lift the scaffolding so that the elevation of the top surface of the rail within the scaffolding changes linearly. Then, grouting is performed on the gap between the scaffolding and the roadbed to eliminate the voids. Among them, an optimal embodiment selects the following parameters: the scaffolding is 4.1m wide, 0.4m thick, and 10.8m long, of which 0.8m extends into the abutment, and there is no sleeper beam. For the continuous reinforcement of the upper and lower surfaces in the transverse direction, HRB400 steel bars with a diameter of 12mm can be used, with a spacing of 210mm, and 52 bars are required for each. For the continuous reinforcement of the upper and lower surfaces in the longitudinal direction, HRB400 steel bars with a diameter of 12mm can be used, with a spacing of 210mm, and 20 bars are required for each.

[0079] The jack working trough is square and bottomless, with outer wall dimensions of 70cm x 70cm, a wall thickness of 4cm, and a height of 30cm. The sides outside the planking area are removable to facilitate the placement and removal of the jacks during treatment. The working trough is normally filled with graded crushed stone and compacted. The location of the jack working trough is shown in Figure 1.

[0080] When lifting the slats, the rail elevation at each end of the slats should remain constant, while the rail elevation between the ends of the slats should change linearly. Before lifting, the rail top elevation should be measured to determine the lifting capacity and lifting rate of each jack. At the end of the lift, the rail elevation should remain linear within the slats.

[0081] The present invention pre-buries jack working grooves under the scaffolding. The jack working grooves are bottomless and are evenly distributed within the scaffolding range of 10m behind the platform. The number of jack working grooves should meet the requirement that when the scaffolding is lifted, the scaffolding between two rows of jacks does not produce a large deflection, thereby causing the elevation of the rail top to change continuously and linearly. The position of the jack working grooves can be determined by the number of jack working grooves and the even distribution of the jack working grooves. The jack working grooves are provided to install jacks and lift the scaffolding when the scaffolding is empty in the later stage. The bottomless jack working grooves can make the jack working grooves pressed into the roadbed when subjected to the pressure of the scaffolding, thereby keeping the top surface of the jack working grooves flush with the surface of the roadbed, so that the bottom surface of the scaffolding is supported by the surface of the roadbed instead of the protruding top surface of the jack working grooves.

[0082] The present invention proposes a 4.1m wide trestle without a bolster and a pre-buried bottomless jack working trough beneath the trestle. The trestle without a bolster is more practical and reduces costs. The bottomless jack working trough keeps the top surface of the jack working trough flush with the roadbed surface, allowing the bottom surface of the trestle to be supported by the roadbed surface rather than the protruding top surface of the jack working trough. To address trestle voids in the later stages, a jack is placed in the jack working trough to lift the trestle so that the elevation of the rail top within the trestle changes linearly. Grouting is then performed to eliminate voids in the gap between the trestle and the roadbed. This, on the one hand, restores the originally bent and deformed trestle to its straightness, significantly improving the stress condition of the trestle and enhancing driving safety. On the other hand, the linearly changing rail top elevation also improves line smoothness and enhances ride comfort.

[0083] The above shows and describes the basic principles, main features, and advantages of the present invention. Those skilled in the art should understand that the present invention is not limited to the above embodiments. The above embodiments and descriptions merely illustrate the principles of the present invention. Various changes and modifications may be made to the present invention without departing from the spirit and scope of the present invention. Such changes and modifications are intended to fall within the scope of the present invention. The scope of protection claimed by the present invention is defined by the appended claims and their equivalents.

Claims

1. A high-speed railway roadbed transition section structure with adjustable elevation, characterized by: By setting jacks under the scaffolding, the scaffolding is lifted to make the elevation of the top surface of the rail within the scaffolding change linearly, and then grouting is performed in the gap between the scaffolding and the roadbed to eliminate the gap.

2. A method for constructing a high-speed railway subgrade transition section structure with adjustable elevation, the method being based on the high-speed railway subgrade transition section structure with adjustable elevation as claimed in claim 1, and characterized in that: The steps include: Step 1: Bury the jack working slot; Step 2: Measure the elevation of the rail top surface before lifting and determine the target elevation of the rail top surface at the jack during lifting; Step 3: Chisel off the sealing layer and excavate graded gravel; Step 4: Install the jack to realize the lifting operation; Step 5: Grouting operation; Step 6: After the mortar strength reaches the design requirements, the jack releases the pressure to allow the slab to fall back onto the solidified mortar layer; Step 7: Re-measure the centerline and elevation of the rail top surface; Step 8: According to the re-measurement results of the centerline and elevation of the rail top surface in step 7, adjust the fasteners and tighten them in time, and make preliminary fine adjustments to the line; Step 9: Repair the seal layer.

3. The method for constructing a high-speed railway roadbed transition section with adjustable elevation according to claim 2, characterized in that: The step 1 includes the following contents: the scaffolding is located below the base plate. When constructing the transition section, a jack working groove is set at the corresponding position. The working groove is square. One side of the working groove is located outside the scaffolding range and can be removed to facilitate the placement and removal of the jack during the jacking operation. It is usually filled and compacted with graded crushed stone.

4. The method for constructing a high-speed railway subgrade transition section with adjustable elevation according to claim 3 is characterized by: The slab is 4.1m wide, 0.4m thick and 10.8m long, of which 0.8m extends into the abutment. The slab is reinforced throughout its upper and lower transverse surfaces and longitudinal surfaces.

5. The method for constructing a high-speed railway roadbed transition section with adjustable elevation according to claim 2, characterized in that: The step 2 includes the following contents: during jacking, the elevation of the top surface of the rail at the jack at the end of the trestle and the sleeper above the part of the trestle extending into the abutment should remain unchanged, so the x-coordinates of these two places and the elevation of the top surface of the rail are taken to determine a line segment as the target elevation line segment of the top surface of the rail within the trestle range, and the target elevations of other jacks are determined by interpolation based on their x-coordinates, and the difference between the target elevation and the actual elevation is the jacking amount.

6. The method for constructing a high-speed railway roadbed transition section with adjustable elevation according to claim 2, characterized in that: The step 3 includes the following contents: after chiseling out the closed layer between the lines, excavating graded gravel within a 0.90m wide range between the two scaffoldings to the bottom of the jack working groove; after chiseling out the closed layer within a range of 1.37m from the outer side of the scaffoldings on the shoulders on both sides, excavating 0.70m thick graded gravel downward and inward along a 45° plane to the bottom of the jack working groove.

7. The method for constructing a high-speed railway subgrade transition section with adjustable elevation according to claim 2, characterized in that: The step 4 includes the following contents: ① Remove the outer side of the jack working slot, remove the graded gravel in the slot, clean and clean the bottom surface of the board in the center of the slot top, clean the bottom of the slot and level it with medium-coarse sand, and then put in a square wooden pad with a side length of 0.60m; ②Place the jack in the center of the wooden pad, connect the cables correctly, and power on the jack. One-time pressurization and pressure relief action ensures the jack works normally; ③ The jacks should be lifted synchronously; after setting the lifting time and lifting rate of each jack, start lifting synchronously; ④ After the synchronous jacking is completed, re-measure the elevation of the top surface of the rail. If it does not reach or exceeds the target elevation of the top surface of the rail, it is necessary to adjust the jacking amount until the target elevation is reached and then lock the jack.

8. The method for constructing a high-speed railway roadbed transition section with adjustable elevation according to claim 2 is characterized by: The step 5 includes the following contents: ①Seam sealing After the slab is lifted, gaps will appear between the side of the slab and the roadbed, and between the bottom of the slab and the top of the jack working slot. To prevent the slurry from flowing out through the gaps, the jacking gaps are sealed with fast-setting materials. An air outlet pipe that is suitable for the gap is exposed at an appropriate position to facilitate observation of the grouting situation, and the slurry is filled and plugged in time; ② Grouting Determine the best water-to-material ratio based on the on-site temperature and humidity, add water to the grouting material and stir until it is evenly mixed, has good fluidity and does not seep water; apply appropriate pressure during grouting; after the main pipe is connected to the shoulder, it should be divided into multiple branches for simultaneous grouting of multiple holes to avoid blockage after one pipe is filled and cause an instantaneous increase in grouting pressure; after the grouting is completed, observe the slurry infiltration in the grouting holes to determine whether the gap under the slab is fully filled, and if not, add grouting. ③Seal the grouting hole After the jacking section of the line meets the requirements after re-testing, the grouting holes are sealed with quick-setting micro-expansive mortar with a strength grade not less than M40.

9. The method for constructing a high-speed railway roadbed transition section with adjustable elevation according to claim 2, characterized in that: The step 7 includes the following contents: checking whether the actual lifting amount is consistent with the planned lifting amount. If there is a difference in the data, it must be processed by adjusting fasteners and other methods to ensure a smooth rail surface.

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