Method for adjusting elevation of ballastless track and ballastless track structure

Abstract

The present invention provides a method for adjusting the elevation of a ballastless track and a ballastless track structure, wherein the ballastless track structure includes a foundation, a roadbed and a supporting layer laid from bottom to top, and is characterized in that the method includes: measuring the track elevation of the track section to be adjusted; breaking the closed layer of the shoulders on both sides, and inserting at least two bearing piles into the foundation on the shoulders on both sides respectively; supporting the supporting layer, excavating the roadbed with a thickness of b; laying a bearing layer with a thickness of c between the remaining roadbed and the supporting layer; lowering the supporting layer by a drop a, and repairing the roadbed and the shoulders. The ballastless track structure also includes: a bearing layer arranged between the supporting layer and the roadbed, and bearing piles with one end inserted into the foundation and one end fixedly connected to the bearing layer to support the bearing layer in a balanced manner from below.

Description

Technical Field

[0001] The invention relates to a method for adjusting the elevation of a track and a track structure, and in particular to a method for adjusting the elevation of a ballastless track and a ballastless track structure. Background Art

[0002] With the rapid development of high-speed railways in my country, some high-speed railway lines with ballastless track structures have successively suffered from arching problems due to the influence of roadbed filling or foundation soil expansion in the track structure. In order to ensure operational safety, speed limit measures have to be taken, which has seriously affected the normal operation of the high-speed railway lines.

[0003] In the existing treatment technology, when it is found that the track has arching disease due to the expansion of soil roadbed filler or foundation soil, the method of excavating the roadbed or foundation with the same thickness as the arching amount can be adopted, and then the track structure elevation is lowered for treatment. This method effectively handles the arching of the track structure thoroughly. However, the above adjustment method has a large amount of engineering and high cost. It is not applicable to soil foundations with continuous deformation of the foundation or roadbed, because frequent excavation of the roadbed or foundation will have a serious impact on the stability and safety of the track structure and the normal operation of the train.

[0004] Therefore, there is an urgent need for a method for quickly adjusting the elevation or a track structure that is convenient for elevation adjustment. Summary of the invention

[0005] The object of the present invention is to provide a method for adjusting the elevation of a ballastless track and a ballastless track structure, which can alleviate or offset the influence caused by the expansion of a roadbed or foundation by arranging a bearing layer, bearing piles and a buffer layer.

[0006] The method for adjusting the elevation of a ballastless track according to the present invention includes: step A, measuring the track elevation of the track section to be adjusted, and determining the amount of track drop a; step B, breaking the closed layer of the shoulders on both sides, and inserting at least two bearing piles into the foundation on the shoulders on both sides, respectively, wherein the compressive strength and stiffness of the bearing piles are greater than the compressive strength and stiffness of the roadbed; step C, supporting the supporting layer, and excavating the roadbed with a thickness of b, wherein b>a; step D, laying a bearing layer with a thickness of c between the remaining roadbed and the supporting layer, wherein the compressive strength and stiffness of the bearing layer are greater than the compressive strength and stiffness of the supporting layer, wherein c≤ba; step E, lowering the supporting layer by a height of a, and repairing the roadbed and the shoulders. The bearing piles are arranged below the bearing layer or penetrate it to support it, and the upper surface of the bearing layer is configured to abut against the supporting layer after completing step E. The above steps not only achieve accurate lowering of the track elevation, but also isolate the supporting layer from the underlying foundation, thereby reducing the impact of foundation expansion on the track structure.

[0007] Preferably, after performing step C and before performing step D, a buffer layer with a thickness of d is laid between the roadbed and the supporting layer, wherein d≤bca, the compressive strength and stiffness of the buffer layer are not greater than that of the roadbed, and the elastic modulus of the buffer layer is less than that of the roadbed. The expansion of the foundation can be alleviated or offset by the elastic deformation, cracking and fracture of the buffer layer.

[0008] Preferably, step B may further include breaking the sealing layer between the wires and inserting the bearing piles into the foundation from between the wires.

[0009] Preferably, the load-bearing piles are constructed as solid structures.

[0010] Alternatively, the load-bearing piles are configured as hollow structures.

[0011] Preferably, in step B, anchor cables are installed at some or all of the load-bearing pile positions before inserting the load-bearing piles, one end of the anchor cable is anchored deeper into the foundation than the load-bearing piles, and the other end passes through the load-bearing piles, extends out of the load-bearing layer, and is connected to the load-bearing layer by means of a tensioning device.

[0012] Preferably, the bearing layer is a slab cast with reinforced concrete.

[0013] Preferably, the buffer layer is made of polystyrene foam board or extruded polystyrene foam plastic.

[0014] Preferably, the load-bearing piles are reinforced concrete piles and / or steel piles.

[0015] The present invention also provides a ballastless track structure, which includes a foundation, a roadbed, and a supporting layer laid from bottom to top, and is characterized in that it also includes: a bearing layer arranged between the supporting layer and the roadbed, the compressive strength and stiffness of the bearing layer are greater than the compressive strength and stiffness of the supporting layer; a bearing pile with one end inserted into the foundation and one end fixedly connected to the bearing layer to support the bearing layer from below in a balanced manner, the compressive strength and stiffness of the bearing pile are greater than the compressive strength and stiffness of the roadbed. The track structure effectively reduces the influence of foundation expansion on the track structure elevation and prolongs the time interval between two track elevation adjustments.

[0016] Preferably, the ballastless track structure further comprises a buffer layer, which is arranged between the bearing layer and the roadbed, the compressive strength and stiffness of the buffer layer are not higher than those of the roadbed, and the elastic modulus of the buffer layer is smaller than that of the roadbed.

[0017] Preferably, the ballastless track structure comprises at least two bearing piles, and the bearing piles are separately arranged on two lateral sides below the bearing layer.

[0018] Preferably, the load-bearing pile is constructed as a hollow structure.

[0019] Preferably, the track structure further comprises an anchor cable, one end of which is anchored deeper into the foundation than the bearing pile, and the other end of which passes through the bearing pile, protrudes out of the bearing layer and is connected to the bearing layer by means of a tension structure.

[0020] Preferably, the bearing layer is a slab cast with reinforced concrete.

[0021] Preferably, the buffer layer is made of polystyrene foam board or extruded polystyrene foam plastic board.

[0022] Preferably, the load-bearing piles are reinforced concrete piles and / or steel piles. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 Schematic diagram of the ballastless track structure according to the present invention.

[0024] Reference Numbers List

[0025] 1. Support layer;

[0026] 2. Bearing layer;

[0027] 3. Buffer layer;

[0028] 4. Roadbed;

[0029] 5. Foundation;

[0030] 6. Bearing piles;

[0031] 7. Anchor cable. DETAILED DESCRIPTION

[0032] Now, with reference to the accompanying drawings, the schematic scheme of the structure disclosed in the present invention is described in detail. Although the accompanying drawings are provided to present embodiments of the present invention, the accompanying drawings are not necessarily drawn to the size of the specific embodiments, and some features may be enlarged, removed or partially cut away to better illustrate and explain the disclosure of the present invention.

[0033] Certain directional terms used in the following description of the drawings, such as "upper", "lower", "lateral", "bottom", will be understood to have their normal meanings and refer to those directions involved when the drawings are normally viewed. Unless otherwise specified, the directional terms described in this specification basically refer to the conventional directions understood by those skilled in the art.

[0034] The ballastless track structure in the prior art generally includes a foundation 5 arranged from bottom to top, a roadbed 4 formed by filling with crushed stones, a supporting layer 1 generally formed by pouring concrete (the supporting layer 1 is also called a base plate when it is composed of reinforced concrete), a track plate generally formed by pouring reinforced concrete, sleepers fixed in the track plate, and a track.

[0035] In order to reduce the influence of soil expansion of the lower roadbed 4 or foundation 5 on the upper track structure, the supporting layer 1 and the upper structure thereof can be isolated from the lower roadbed 4 and foundation 5, so that Figure 1 As shown, the track structure of the present invention further includes a bearing layer 2. The bearing layer 2 is arranged between the roadbed 4 and the supporting layer 1, and its upper surface is preferably directly in contact with the bottom surface of the supporting layer 1 facing the roadbed 4. The compressive strength and stiffness of the bearing layer 2 are designed to be at least greater than the compressive strength and stiffness of the supporting layer 1. The bearing layer 2 is generally made of C40 reinforced concrete material and can be prefabricated or cast on site.

[0036] In order to better transfer the load on the bearing layer 2 to the soil below and enhance the stability of the track structure, the track structure also provides a bearing pile 6 that can be fixedly connected (e.g., hingedly connected) to the bearing layer 2. The bearing pile 6 is arranged below the bearing layer 2 (when the bearing layer 2 is a prefabricated plate) or passes through it (when the bearing layer 2 is cast on site) to support it. The compressive strength and stiffness of the bearing pile 6 should be designed to be greater than the compressive strength and stiffness of the roadbed 4.

[0037] It is preferred to use more than two bearing piles 6, which are at least separately arranged on the lateral sides below the bearing layer 2 to provide balanced support to the upper bearing layer 2 as needed, thereby ensuring the balance and stability of the bearing layer 2. The bearing piles 6 can be inserted into the track structure below the supporting layer 1 by drilling, hammering, pressing, etc., and in order to ensure the stability of the upper structure, they must be inserted into the foundation 5 for at least a certain distance. The bearing piles 6 can also be arranged in the corresponding foundation 5 located below the railway shoulder or line. There is no restriction on the shape and structure of the bearing piles 6, which can be round, square, solid or hollow. The bearing piles 6 can be reinforced concrete piles or steel piles. At the same time, according to the stress conditions of the bearing layer 2 and the material selected for the bearing piles 6, the bearing piles 6 can be densely arranged. When the bearing piles 6 are used to support the bearing layer 2, a partial gap can also be left between the roadbed 4 and the bearing layer 2, thereby leaving more space for soil expansion and slowing down its arching effect on the bearing layer 2.

[0038] Preferably, the same or less number of anchor cables 7 as the number of the bearing piles 6 can be provided to increase the anchoring force of the bearing piles 6. Preferably, the anchor cables 7 can be arranged as follows: holes are drilled toward the foundation 5 at the positions of the bearing piles 6 to be used with the anchor cables 7, the anchor cables 7 are inserted into the holes and fixed relative to the foundation 5 by means of grouting or the like, wherein the depth of the anchor cables 7 inserted into the foundation 5 is greater than or much greater than the depth of the bearing piles 6 inserted into the foundation 5 as required.

[0039] Preferably, when the bearing pile 6 is a hollow structure, for example, a hollow steel pipe is used, the bearing layer 2 can be poured around the bearing pile 6 or the bearing pile 6 can be inserted into the bearing layer 2, and preferably, the upper end of the bearing pile 6 cannot extend out of the upper surface of the bearing layer 2. The anchor cable 7 can pass through the hollow interior of the bearing pile 6 until it extends out of the upper bearing layer 2, and at the same time, it is tensioned and fixed to the upper surface of the bearing layer 2 by means of a tensioning device, such as an anchor head structure.

[0040] In addition, the present invention also provides a buffer layer 3 to offset the expansion of the soil and / or reduce the impact of soil expansion deformation. The buffer layer 3 is preferably arranged between the roadbed 4 and the bearing layer 2, and its thickness can be set as needed according to the expansion characteristics of the soil. The compressive strength and rigidity of the buffer layer 3 are not greater than the roadbed 4, and the elastic modulus of the buffer layer 3 is less than that of the roadbed 4. Preferably, polystyrene foam board (EPS board) or extruded polystyrene foam plastic (XPS board) is used. Therefore, when the buffer layer 3 is squeezed by the expansion of the soil, it will first produce a certain amount of deformation to offset the expansion of the soil below. When the deformation reaches a certain degree, the buffer layer 3 will produce cracks under the action of the soil expansion force and then be crushed. This process is the process of releasing the soil expansion force. At the same time, the buffer layer 3 can also fill the gap between the bearing layer 2 and the roadbed 4, better meet the requirements of the track structure on the compactness, and provide better support for the upper track structure.

[0041] In addition, the above structure can also realize active adjustment of the track elevation with the help of the anchor cable 7. That is, when it is found that the track elevation rises, the anchor cable 7 exposed outside the bearing layer 2 can be further tightened to press down the bearing layer 2, thereby actively crushing the buffer layer 3, thereby releasing the expansion force of the soil, and realizing the downward adjustment of the track elevation.

[0042] The present invention further provides a method for adjusting the elevation of a ballastless track, which uses the track structural components described above to adjust a track that has been laid but has an arching problem. The track elevation is lowered during construction by removing the roadbed 4, and the track elevation is quickly and effectively adjusted by arranging a bearing layer 2, bearing piles 6, and a buffer layer 3.

[0043] The method mainly includes the following steps: first, measuring the track elevation of the track section to be adjusted and determining the amount of track drop a; next, breaking the closed layer of the shoulder (when it is a two-way track, the line interval can be broken as needed), and at least two bearing piles 6 can be inserted into the corresponding foundation 5 at a distance at the shoulder and / or line interval by various methods such as drilling, hammering, and pressing. The compressive strength and rigidity of the bearing pile 6 are greater than the compressive strength and rigidity of the roadbed 4. Optionally, when hollow bearing piles 6 are used, anchor cables 7 can be provided at some or all of the bearing piles 6 before inserting the bearing piles 6, that is, holes are drilled at the positions where the bearing piles 6 are to be inserted, one end of the anchor cable 7 is inserted into the hole and can be fixed by grouting or the like, which is fixed deeper to the foundation 5 than the bearing piles 6, and the other end of the anchor cable 7 passes through the bearing piles 6 and extends out of the bearing layer 2 and is connected to the bearing layer 2, for example, by a tensioning device.

[0044] In the next step, a supporting device is used to support the bearing layer 1 and the track structure above it, and the roadbed 4 with a thickness of b is excavated. The distance b should be greater than the amount of track fall a so that it is sufficient to complete the track lowering. At the same time, it is still necessary to leave space for the bearing layer 2 (and buffer layer 3) below, so b>a is selected.

[0045] In the next step, a bearing layer 2 with a thickness of c is laid between the remaining roadbed 4 and the supporting layer 1, wherein the compressive strength and stiffness of the bearing layer 2 are greater than the compressive strength and stiffness of the supporting layer 1, wherein, when the buffer layer 3 is not laid, c=ba; when the buffer layer 3 is laid, c<ba, thereby leaving space for the buffer layer 3.

[0046] Preferably, before laying the supporting layer 1, a buffer layer 3 (such as an EPS board) with a thickness of d is laid between the roadbed 4 and the supporting layer 1, where d≤bca. When =, the buffer layer 3 and its upper and lower track structures are arranged closely, which can provide better support for the upper track structure. When <, it means that there is still a certain gap between the buffer layer 3 and its upper and lower track structures, which leaves some space for the soil to continue to expand. Therefore, the laying thickness of the buffer layer 3 can be selected according to the expansion size of the roadbed 4 and foundation 5 for laying the track.

[0047] Finally, the supporting layer 1 is lowered by the amount a, wherein after the lowering is completed, the upper surface of the bearing layer 2 should abut against the supporting layer 1, and the bearing layer 2 directly supports the supporting layer 1 to repair the roadbed 4 and the line and / or shoulder.

[0048] In addition, in order to minimize the impact on the normal operation of the railway, the above method can be performed in sections along the length of the track to be adjusted.

Claims

1. A method for adjusting the elevation of a ballastless track, wherein the ballastless track structure comprises a foundation (5), a roadbed (4) and a supporting layer (1) laid from bottom to top, wherein: The method comprises: Step A, measuring the track elevation of the track section to be adjusted and determining the track drop amount a; Step B, breaking the closed layer of the shoulders on both sides, inserting at least two bearing piles (6) into the foundation (5) on the shoulders on both sides, respectively, wherein the compressive strength and rigidity of the bearing piles (6) are greater than the compressive strength and rigidity of the roadbed (4); Step C, supporting the support layer (1), and excavating the roadbed (4) with a thickness of b, wherein b>a; Step D, laying a bearing layer (2) with a thickness of c between the remaining roadbed (4) and the supporting layer (1), wherein the compressive strength and stiffness of the bearing layer (2) are greater than the compressive strength and stiffness of the supporting layer (1), wherein c≤ba; Step E, lowering the supporting layer (1) by a drop a, and repairing the roadbed (4) and the road shoulder; The bearing piles (6) are arranged below the bearing layer (2) or penetrate it to provide balanced support thereto, and the upper surface of the bearing layer (2) is arranged to abut against the supporting layer (1) after completing step E.

2. The method according to claim 1, characterized in that: After executing step C and before executing step D, a buffer layer with a thickness of d is laid between the roadbed and the supporting layer, wherein d≤bca, the compressive strength and stiffness of the buffer layer are not greater than the compressive strength and stiffness of the roadbed, and the elastic modulus of the buffer layer is less than the elastic modulus of the roadbed.

3. The method according to claim 1, characterized in that: Step B may also include breaking the sealing layer between the wires and inserting the bearing piles into the foundation from between the wires.

4. The method according to claim 1, characterized in that: The load-bearing piles are constructed as solid structures.

5. The method according to claim 1, characterized in that: The load-bearing piles are constructed as hollow structures.

6. The method according to claim 5, characterized in that In step B, anchor cables are installed at some or all of the load-bearing pile positions before inserting the load-bearing piles, one end of the anchor cable is fixed to the foundation deeper than the load-bearing piles, and the other end passes through the load-bearing piles, extends out of the load-bearing layer, and is connected to the load-bearing layer by means of a tensioning device.

7. The method according to claim 2, characterized in that: The bearing layer is a plate cast by reinforced concrete, the buffer layer is made of polystyrene foam board or extruded polystyrene foam plastic board, and the bearing piles are reinforced concrete piles and / or steel piles.

8. A ballastless track structure, comprising a foundation (5), a roadbed (4), and a supporting layer (1) laid from bottom to top, characterized in that: include: A bearing layer (2) arranged between the supporting layer (1) and the roadbed (4), wherein the compressive strength and rigidity of the bearing layer (2) are greater than the compressive strength and rigidity of the supporting layer (1); A bearing pile (6) has one end inserted into the foundation (5) and the other end fixedly connected to the bearing layer (2) to support the bearing layer (2) in a balanced manner from below, and the compressive strength and rigidity of the bearing pile (6) are greater than the compressive strength and rigidity of the roadbed (4).

9. The ballastless track structure according to claim 8, characterized in that: It also includes a buffer layer, which is arranged between the bearing layer and the roadbed, the compressive strength and stiffness of the buffer layer are not higher than the compressive strength and stiffness of the roadbed, and the elastic modulus of the buffer layer is smaller than the elastic modulus of the roadbed; and the laying thickness of the buffer layer is set according to the expansion properties of the roadbed (4) and the foundation (5) for actually laying the track.

10. The ballastless track structure according to claim 8, characterized in that: At least two bearing piles are included, and the bearing piles are separately arranged on two lateral sides below the bearing layer.

11. The ballastless track structure according to claim 10, characterized in that: The load-bearing piles are constructed as hollow structures.

12. The ballastless track structure according to claim 11, characterized in that: It also includes an anchor cable, one end of which is anchored deeper into the foundation than the bearing pile, and the other end of which passes through the bearing pile, protrudes out of the bearing layer, and is connected to the bearing layer by means of a tensioning device.

13. The ballastless track structure according to claim 9, characterized in that: The bearing layer is a plate cast by reinforced concrete, the buffer layer is made of polystyrene foam board or extruded polystyrene foam plastic board, and the bearing piles are reinforced concrete piles and / or steel piles.

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