High-speed railway ballastless track subgrade surface semi-paving waterproof sealing structure and construction method

Abstract

The application discloses a high-speed railway ballastless track roadbed surface layer semi-paving waterproof sealing structure and a construction method. The high-speed railway ballastless track roadbed surface layer semi-paving waterproof sealing structure comprises a concrete base plate, characterized in that a high-toughness concrete sealing layer structure is paved on the upper part of the roadbed surface layer on the two sides of the concrete base plate, the high-toughness concrete sealing layer structure extends to the bottom of the concrete base plate at one end of the side of the concrete base plate, and the end of the extending end of the high-toughness concrete sealing layer structure is provided with a convex blocking table and is integrally poured with the concrete base plate. The high-toughness concrete structure with the convex blocking table at the end is used for waterproof sealing, the phenomenon of water infiltration from the roadbed surface layer to the inside of the roadbed can be avoided, the slippage between the concrete base plate and the waterproof sealing layer is limited through the convex blocking table, the semi-paving waterproof sealing structure is adopted, the high-toughness concrete consumption is reduced, and the engineering cost is greatly saved.

Description

Technical Field

[0001] This invention relates to a semi-waterproof sealing structure for the surface layer of ballastless track subgrade for high-speed railways, belonging to the field of high-speed railway technology. This invention also relates to a construction method for the aforementioned semi-waterproof sealing structure for the surface layer of ballastless track subgrade for high-speed railways. Background Technology

[0002] my country has a vast area of ​​permafrost, and in recent years, with the continuous construction of high-speed railways, the mileage of high-speed railways in permafrost areas has been increasing. Operational data shows that rainfall causes water accumulation on the roadbed surface. This moisture seeps into the roadbed interior, and under the combined effects of temperature and moisture, fine particles in the roadbed fill material freeze, causing internal volume expansion and severe frost heave deformation of the subgrade surface. This frost heave deformation causes the track structure to deform accordingly. This deformation, transmitted to the rail surface, causes severe track irregularities, affecting the service life and condition of the track structure, and threatening the safe operation of high-speed trains.

[0003] To address the issue of frost heave in high-speed railway subgrades, scholars have proposed using a waterproof sealing structure on the subgrade surface to prevent moisture infiltration. The most widely used method is the full-section asphalt concrete sealing structure. However, field investigations have revealed the following problems: 1. Asphalt concrete construction is greatly affected by temperature, significantly limiting construction conditions; 2. Under temperature loads, the asphalt concrete sealing layer can develop transverse cracks due to thermal expansion and contraction; 3. The base slab concrete can only be poured after the asphalt concrete sealing layer has cured to a certain strength, leading to an interface between the old and new concrete layers, which may result in separation or even slight slippage after prolonged operation; 4. The full-section sealing structure requires a large paving area and is costly. Summary of the Invention

[0004] To address the aforementioned deficiencies in existing technologies, this invention provides a semi-waterproof sealing structure for the surface of ballastless track subgrade in high-speed railways. This structure offers advantages such as low installation cost, effective prevention of water seepage from the subgrade surface into the subgrade interior, and limitation of slippage between the concrete base slab and the waterproof sealing layer.

[0005] The present invention is achieved through the following technical solution: a semi-waterproof and sealed structure for the surface layer of ballastless track subgrade of high-speed railway, comprising a concrete base plate, characterized in that: a high-toughness concrete sealing layer structure is laid on the upper part of the subgrade bed surface layer on both sides of the concrete base plate, the high-toughness concrete sealing layer structure extends to the bottom of the concrete base plate at one end located on the side of the concrete base plate, and the end of its extended end has a convex baffle and is cast integrally with the concrete base plate.

[0006] In this invention, a high-toughness concrete layer is used as the sealing layer, which is less affected by temperature during construction and will not cause transverse cracks due to thermal expansion and contraction. The high-toughness concrete structure with convex retaining platforms at the ends is used for waterproof sealing, which can prevent water from seeping from the surface of the roadbed into the interior of the roadbed. Furthermore, the convex retaining platforms restrict the slippage between the concrete base plate and the waterproof sealing layer. The use of a semi-laid waterproof sealing structure reduces the amount of high-toughness concrete used, which greatly saves project costs.

[0007] Furthermore, the end of the convex retaining wall of the high-toughness concrete sealing layer structure is located outside the centerline of the rail.

[0008] This invention also provides a construction method for the above-mentioned semi-paved waterproof sealing structure of the surface layer of high-speed railway ballastless track subgrade, the technical solution of which includes the following steps:

[0009] (1) Through finite element simulation calculation, the stress distribution characteristics of ballastless track and high toughness concrete closed layer structure are determined, including the Mises stress distribution inside the track structure under the vertical load of the train through finite element simulation calculation, and the shear stress distribution of the track structure under the lateral vibration of the train through finite element simulation calculation.

[0010] (2) Determine the relative position between the high-toughness concrete sealing layer structure and the concrete base plate based on the stress distribution characteristics of the ballastless track and the high-toughness concrete sealing layer structure: Based on the Mises stress distribution of the track structure under the vertical load of the train calculated by finite element simulation, determine the diffusion radius b at the position of 30% of the maximum normal stress. At this time, the lateral distance a from the end of the convex abutment to the center line of the rail must satisfy a≥b; Based on the shear stress distribution of the track structure under the lateral vibration of the train calculated by finite element simulation, determine the width c and the height d of the convex abutment.

[0011] (3) Based on the determined relative position between the high-toughness concrete sealing layer structure and the concrete base plate, the high-toughness concrete sealing layer structure is laid on the surface of the subgrade. After the high-toughness concrete sealing layer structure has been cured by film covering and has reached the initial setting strength, the concrete base plate is poured on top of it.

[0012] Furthermore, the flexural strength of the high-toughness concrete sealing layer structure in the non-structural layer of the subgrade is greater than the shear stress on the high-toughness concrete sealing layer structure by the edge of the concrete base plate under the vertical load of the train.

[0013] Furthermore, a finite element model is established using the following formula.

[0014] F(t)=P0+P1sinω1t(1)

[0015] P1=M0a1ω1 2(2)

[0016] ω1=2πv / L(3)

[0017] Where P0 is the static load of the wheel, P1 is the additional vibration load caused by rail irregularities, ω1 is the circular frequency of vibration, M0 is the unsprung mass, a1 is the geometric irregularity sag of the irregularity control condition, v is the train speed, and L is the typical wavelength of the geometric irregularity.

[0018] The beneficial effects of this invention are as follows: This invention uses a high-toughness concrete structure with convex end blocks for waterproof sealing, preventing water from seeping from the surface of the roadbed into the interior, and the convex end blocks effectively limit the slippage between the concrete base plate and the waterproof sealing layer; using a high-toughness concrete layer as the sealing layer can prevent water seepage, and the construction is less affected by temperature, preventing transverse cracks caused by thermal expansion and contraction; this invention uses a semi-laid waterproof sealing structure, reducing the amount of high-toughness concrete used and greatly saving project costs. Attached Figure Description

[0019] Figure 1 This is a schematic diagram of the cross-section of the ballastless track subgrade in this invention;

[0020] In the diagram, 1 is the track slab; 2 is the self-compacting concrete; 3 is the concrete base slab; 4 is the high-toughness concrete sealing layer structure; 4-1 is the convex retaining wall; and 5 is the roadbed. Detailed Implementation

[0021] The invention will be further described below through non-limiting embodiments and in conjunction with the accompanying drawings:

[0022] As shown in the attached figure, a semi-waterproof sealing structure for the surface layer of a ballastless track subgrade for high-speed railway includes a concrete base plate 3. A high-toughness concrete sealing layer structure 4 is laid on the upper part of the subgrade bed 5 on both sides of the concrete base plate 3. One end of the high-toughness concrete sealing layer structure 4 located on the side of the concrete base plate extends to the bottom of the concrete base plate 3, and the end of its extended end has a convex baffle 4-1. The convex baffle 4-1 is cast integrally with the concrete base plate 3.

[0023] The high-toughness concrete sealing layer structure 4 in this invention is formed by casting high-toughness concrete. High-toughness concrete is an existing technology, which has higher strength, toughness, crack resistance and durability compared to ordinary concrete.

[0024] The construction method for the semi-waterproof sealing structure of the surface layer of the ballastless track subgrade of high-speed railway mentioned above includes the following steps:

[0025] (1) Conduct finite element simulation calculations to determine the stress distribution characteristics of the ballastless track and the high-toughness concrete sealing layer structure:

[0026] ①Establish a three-dimensional spatial model of the ballastless track-high toughness concrete sealing layer structure-subgrade.

[0027] ② Applying a dynamic load to a train can be expressed as a sinusoidal function containing vibration amplitude and frequency, i.e.:

[0028] F(t)=P0+P1sinω1t(1)

[0029] P1=M0a1ω1 2 (2)

[0030] ω1=2πv / L(3)

[0031] Where P0 is the static load of the wheel, P1 is the additional vibration load caused by rail irregularities, ω1 is the circular frequency of vibration, M0 is the unsprung mass, a1 is the geometric irregularity sag of the irregularity control condition, v is the train speed, and L is the typical wavelength of the geometric irregularity.

[0032] ③ The ballastless track and the high-toughness concrete sealing layer structure, as well as the high-toughness concrete sealing layer structure and the roadbed, all adopt surface-to-surface contact with contact stiffness, taking into account the relative movement between structural layers to better realize the force transmission between structures. The bottom of the roadbed adopts fixed constraints. The longitudinal direction of the track structure adopts symmetrical boundaries to overcome the influence of boundary effects.

[0033] ④ The Mises stress distribution characteristics inside the track structure were obtained through finite element simulation. The stress is greatest directly below the rail, then diffuses downwards in a semi-circular pattern and gradually decreases. Mises stress contour lines were plotted, centered on a point on the track slab surface directly below the rail, and radiating outwards. The diffusion radius at 30% of the maximum normal stress was determined.

[0034] ⑤ The shear stress distribution characteristics of the track structure under the action of lateral vibration of the train were obtained by finite element simulation calculation.

[0035] (2) Based on the stress distribution characteristics of the ballastless track and the high-toughness concrete sealing layer structure, the relative position between the high-toughness concrete sealing layer structure and the concrete base plate.

[0036] Based on the Mises stress distribution of the track structure under the vertical load of the train obtained by finite element simulation, the diffusion radius b at the position of 30% of the maximum normal stress is determined. At this time, the lateral distance a from the end of the convex abutment 4-1 to the center line of the rail must satisfy a≥b.

[0037] Based on the shear stress distribution of the track structure under the lateral vibration of the train obtained by finite element simulation, the width c and height d of the convex abutment are determined.

[0038] The thickness e of the high-toughness concrete sealing layer structure in the non-structural layer of the subgrade should ensure that its flexural strength is greater than the shear stress on the high-toughness concrete sealing layer structure by the edge of the concrete base plate 3 under the vertical load of the train, and its thickness needs to meet the requirements of economy.

[0039] (3) Based on the determined relative position between the high-toughness concrete sealing layer structure 4 and the concrete base plate 3, high-toughness concrete is laid on the surface of the subgrade to form the high-toughness concrete sealing layer structure 4. After the high-toughness concrete sealing layer structure 4 has been cured by film covering and has reached the initial setting strength, the concrete base plate 3 is poured on top of it.

[0040] The other parts in this embodiment are all existing technologies and will not be described in detail here.

Claims

1. A semi-waterproof and sealed surface layer structure for ballastless track subgrade of high-speed railway, comprising a concrete base slab, characterized in that: A high-toughness concrete sealing layer structure is laid on the upper part of the subgrade surface layer on both sides of the concrete base plate. The high-toughness concrete sealing layer structure extends to the bottom of the concrete base plate at one end, and the end of its extension has a convex baffle and is cast into the concrete base plate.

2. The semi-waterproof and sealed surface layer structure for high-speed railway ballastless track subgrade as described in claim 1, characterized in that: The end of the convex retaining wall of the high-toughness concrete sealing layer structure is located outside the centerline of the rail.

3. A construction method for a semi-waterproof sealing structure for the surface layer of high-speed railway ballastless track subgrade as described in any one of claims 1-2, characterized in that: Includes the following steps: (1) Through finite element simulation calculation, the stress distribution characteristics of ballastless track and high toughness concrete closed layer structure are determined, including the Mises stress distribution inside the track structure under the vertical load of the train through finite element simulation calculation, and the shear stress distribution of the track structure under the lateral vibration of the train through finite element simulation calculation. (2) Determine the relative position between the high-toughness concrete sealing layer structure and the concrete base plate based on the stress distribution characteristics of the ballastless track and the high-toughness concrete sealing layer structure: Based on the Mises stress distribution of the track structure under the vertical load of the train calculated by finite element simulation, determine the diffusion radius b at the position of 30% of the maximum normal stress. At this time, the lateral distance a from the end of the convex abutment to the center line of the rail must satisfy a≥b; Based on the shear stress distribution of the track structure under the lateral vibration of the train calculated by finite element simulation, determine the width c and the height d of the convex abutment. (3) Based on the determined relative position between the high-toughness concrete sealing layer structure and the concrete base plate, the high-toughness concrete sealing layer structure is laid on the surface of the subgrade. After the high-toughness concrete sealing layer structure has been cured by film covering and has reached the initial setting strength, the concrete base plate is poured on top of it.

4. The construction method of the semi-waterproof sealing structure for the surface layer of high-speed railway ballastless track subgrade according to claim 3, characterized in that: The flexural strength of the high-toughness concrete sealing layer structure in the non-structural layer of the subgrade is greater than the shear stress on the high-toughness concrete sealing layer structure by the edge of the concrete base plate under the vertical load of the train.

5. The construction method of the semi-waterproof sealing structure for the surface layer of high-speed railway ballastless track subgrade according to claim 3 or 4, characterized in that: The finite element model is established using the following formula. F(t)=P0+P1sinω1t (1) P1=M0a1ω1 2 (2) ω1=2πv / L (3) Where F(t) is the train vibration load, t is the train time point during irregular operation, P0 is the wheel static load, P1 is the additional vibration load caused by rail irregularity, ω1 is the vibration angular frequency, M0 is the unsprung mass, a1 is the geometric irregularity sag of the irregularity control condition, v is the train speed, and L is the typical wavelength of geometric irregularity.

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