A technology and method for the construction of railway subgrade closure

Abstract

This invention relates to the field of railway subgrade construction technology, and discloses a process and method for closed construction of railway subgrade bed, including the following steps: Step 1: Close off and protect the construction section to prevent unauthorized personnel and animals from entering, while simultaneously coordinating with the station, railway operations, signaling, and other units and delivering cooperation notices, and simultaneously repairing ditches and slopes within the construction area; Step 2: Conduct on-site exploration of the subgrade. This invention replaces the expansive soil in the construction section and performs dynamic compaction on the entire section, compacting the cohesive soil and original soil to increase their load-bearing capacity and reduce settlement. Then, the subgrade is subjected to prolonged vibration to further compact the soil, and after laying the ballast, continuous vibration is applied again to reduce and compact the spacing between the ballast sections. This prevents subsidence of the subgrade and ballast caused by vibration after train passage, ensuring the reliability of the subgrade and rails after installation.

Description

Technical Field

[0001] This invention relates to the field of railway subgrade construction technology, specifically to a process and method for the closed construction of railway subgrade bed. Background Technology

[0002] Currently, expansive soil is a special type of clay widely distributed both domestically and internationally. This type of soil swells when exposed to water and shrinks and cracks when it loses water. Repeated expansion and contraction significantly reduce the soil's strength, posing a great threat to the safety of engineering projects. It often causes road surface cracking, foundation settlement, and slope collapse. On railway subgrades, the main defects it causes include slope instability, landslides, subgrade settlement, formation of ballast cavities under the subgrade, shoulder bulging and extrusion, and subgrade mud pumping. The presence of expansive soil greatly affects the operation of trains on railway tracks, posing a significant threat to people's lives and property.

[0003] The occurrence of these diseases is closely related to the particle size distribution (mainly clay), mineral chemical composition (kaolinite, montmorillonite, and illite), crystal structure (superimposed silicon-oxygen tetrahedra and aluminum-hydrogen-oxygen octahedra), and hydrophilicity of expansive soil. Due to the hydrophilicity of clay minerals, coupled with the repeated action of train dynamic loads, the subgrade soil softens, resulting in various forms of subgrade diseases, and even leading to subgrade instability, seriously affecting traffic safety. Existing methods include compaction, physical improvement, chemical improvement, moisture retention, and soil replacement. However, after actual treatment, laying ballast on the subgrade can distribute the weight of trains and tracks onto the subgrade, reducing vibration and noise caused by passing trains and providing good drainage. However, the long-term vibration generated by trains can easily cause subgrade and ballast settlement, posing a threat to the safe operation of the railway. Therefore, we propose a process and method for the closed construction of railway subgrade. Summary of the Invention

[0004] The purpose of this invention is to provide a process and method for the closed construction of railway subgrade. By replacing the expansive soil in the construction section and performing dynamic compaction on the entire section, the cohesive soil and the original soil are compacted to increase their load-bearing capacity and reduce settlement. Then, the subgrade is subjected to long-term vibration to make the soil even more compact. After laying the ballast, continuous vibration is performed again to reduce the spacing between the ballast and make it even more compact. This can prevent settlement of the subgrade and ballast caused by vibration after trains pass, ensure the reliability of the subgrade and rails after installation, and solve the problems mentioned in the background art.

[0005] To achieve the above objectives, the present invention provides the following technical solution: a process and method for the closure construction of railway subgrade, comprising the following steps:

[0006] Step 1: Close off and protect the construction section to prevent unauthorized personnel and animals from entering. At the same time, contact the station to coordinate with the vehicle and electrical departments and deliver cooperation notices. Simultaneously repair the ditches and slopes within the construction area.

[0007] Step 2: Conduct on-site exploration of the roadbed to identify areas with high expansive soil content. Then, use excavators and other excavation tools to remove all the expansive soil. After that, backfill with sufficient cohesive soil that meets the moisture content requirements. Then, use a dynamic compaction machine to perform dynamic compaction on the roadbed section with backfilled cohesive soil and all other road sections, thereby improving the bearing capacity of the roadbed and reducing settlement.

[0008] Step 3: Make columnar holes on both sides of the roadbed, insert vibrating rods and connect them to the vibrating motor, so that the vibrating rods are close to the inner surface of the holes, and then start the vibrating motor to drive the vibrating rods to vibrate continuously and act on the compacted roadbed, thus compacting the roadbed again.

[0009] Step 4: Lay a layer of crushed stone and cement on the surface of the subgrade, set a transverse drainage slope on the surface of the subgrade, spray a sealing layer material, lay a waterproof adhesive cloth, and then lay a sufficient amount of ballast on the surface of the subgrade and install the rails on its surface.

[0010] Step 5: Restart the vibratory motor to drive the vibratory rod to vibrate continuously and apply it to the compacted roadbed with ballast, so as to compact the roadbed and ballast. Then remove the vibratory rod and pour concrete into the original hole. After that, measure and calibrate the rails installed on the ballast surface to ensure that the installation of the rails fully meets the requirements.

[0011] Step Six: Place a freight train on the rails and load it with sufficient weight. Let it travel back and forth between the rails under construction to test the reliability of the roadbed. Once it meets the requirements, the test train can be removed, and the construction area can be unsealed and opened to traffic.

[0012] In a preferred embodiment of the present invention, the moisture content of the backfill soil in step two shall not exceed approximately 8%-12% of the total content of sandy soil and approximately 12%-15% of the total content of silty clay.

[0013] In a preferred embodiment of the present invention, the compaction time of the backfill soil in step two should be much longer than that of the original soil, and the weighing capacity of the roadbed needs to be tested after compaction.

[0014] In a preferred embodiment of the present invention, the total duration of vibration in step three shall not be less than 24 hours, and the duration of each vibration shall not be less than 2 hours.

[0015] In a preferred embodiment of the present invention, the total duration of vibration in step 5 shall not be less than 48 hours, and the duration of each vibration shall not be less than 3 hours.

[0016] In a preferred embodiment of the present invention, the inclination angle of the drainage slope in step four should be between 4° and 10°.

[0017] In a preferred embodiment of the present invention, when installing the rails in step four, manual backfilling of ballast is required at the beginning and end of the track for transition; a gantry crane is used to lift the rails, and a ballast bag is symmetrically placed under each sleeper in the middle section, with ballast bags piled up next to them and leveled.

[0018] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0019] 1. This invention replaces the expansive soil in the construction section and performs dynamic compaction on all sections to compact the cohesive soil and the original soil, thereby increasing their load-bearing capacity and reducing settlement. Then, the roadbed is subjected to long-term vibration to make the soil even more compact. After laying the ballast, continuous vibration is performed again to reduce the spacing between the ballast and make it even more compact. This can prevent settlement of the roadbed and ballast caused by vibration after trains pass, thus ensuring the reliability of the roadbed and rails after installation.

[0020] 2. This invention improves drainage during rainy weather by setting a transverse drainage slope with an inclined angle and spraying a sealing layer material on the subgrade during roadbed construction, thereby preventing rainwater accumulation from eroding the roadbed. Attached Figure Description

[0021] Other features, objects, and advantages of the present invention will become more apparent from the following detailed description of non-limiting embodiments with reference to the accompanying drawings:

[0022] Figure 1 This is a flowchart illustrating the process and method for the closed construction of railway subgrade bed according to the present invention. Detailed Implementation

[0023] To make the technical means, creative features, objectives and effects of this invention easier to understand, the invention will be further described below in conjunction with specific embodiments.

[0024] Please see Figure 1 This invention provides a technical solution: a process and method for sealing railway subgrade, comprising the following steps:

[0025] Step 1: Close off and protect the construction section to prevent unauthorized personnel and animals from entering. At the same time, contact the station to coordinate with the vehicle and electrical departments and deliver cooperation notices. Simultaneously repair the ditches and slopes within the construction area.

[0026] Step 2: Conduct on-site exploration of the roadbed to identify areas with high expansive soil content. Then, use excavators and other excavation tools to remove all the expansive soil. After that, backfill with sufficient cohesive soil that meets the moisture content requirements. Then, use a dynamic compaction machine to perform dynamic compaction on the roadbed section with backfilled cohesive soil and all other road sections, thereby improving the bearing capacity of the roadbed and reducing settlement.

[0027] Step 3: Make columnar holes on both sides of the roadbed, insert vibrating rods and connect them to the vibrating motor, so that the vibrating rods are close to the inner surface of the holes, and then start the vibrating motor to drive the vibrating rods to vibrate continuously and act on the compacted roadbed, thus compacting the roadbed again.

[0028] Step 4: Lay a layer of crushed stone and cement on the surface of the subgrade, set a transverse drainage slope on the surface of the subgrade, spray a sealing layer material, lay a waterproof adhesive cloth, and then lay a sufficient amount of ballast on the surface of the subgrade and install the rails on its surface.

[0029] Step 5: Restart the vibratory motor to drive the vibratory rod to vibrate continuously and apply it to the compacted roadbed with ballast, so as to compact the roadbed and ballast. Then remove the vibratory rod and pour concrete into the original hole. After that, measure and calibrate the rails installed on the ballast surface to ensure that the installation of the rails fully meets the requirements.

[0030] Step Six: Place a freight train on the rails and load it with sufficient weight. Let it travel back and forth between the rails under construction to test the reliability of the roadbed. Once it meets the requirements, the test train can be removed, and the construction area can be unsealed and opened to traffic.

[0031] Furthermore, the moisture content of the backfill soil in step two should not exceed approximately 8%-12% of the total content of sandy soil and approximately 12%-15% of the total content of silty clay.

[0032] Furthermore, in step two, the compaction time for the backfill soil should be much longer than that for the original soil, and after compaction, the weighing capacity of the roadbed needs to be tested.

[0033] Furthermore, the total duration of vibration in step three shall not be less than 24 hours, and the duration of each vibration shall not be less than 2 hours.

[0034] Furthermore, the total duration of vibration in step 5 shall not be less than 48 hours, and the duration of each vibration shall not be less than 3 hours.

[0035] Furthermore, the slope inclination angle of the drainage slope in step four should be between 4° and 10°.

[0036] Furthermore, in step four, when installing the rails, manual backfilling of ballast is required at the beginning and end of the slope for transition; when using a gantry crane to lift the rails, a ballast bag is symmetrically placed under each sleeper in the middle section, and ballast bags are piled up next to them and leveled.

[0037] When using a process and method for enclosing the subgrade of a railway, the construction section is sealed off and protected to prevent unauthorized personnel and animals from entering. Simultaneously, station personnel coordinate with train operations, electrical engineering, and other units, delivering cooperation notices. Ditches and slope protection within the construction area are repaired concurrently. The subgrade site is surveyed to identify areas with high expansive soil content. Excavators and other excavation tools are then used to remove all the expansive soil, followed by backfilling with sufficient cohesive soil meeting the required moisture content. A dynamic compaction machine is then used to compact the backfilled cohesive soil section and all other sections, thereby increasing the subgrade's bearing capacity and reducing settlement. Columnar holes are drilled on both sides of the subgrade, vibratory rods are inserted and connected to a vibratory motor, ensuring the vibratory rods are pressed tightly against the inner surface of the holes. The vibratory motor is then started to drive the vibratory rods to vibrate continuously. The vibration is applied to the compacted roadbed, further compacting it. A layer of crushed stone and cement is laid on the surface of the roadbed, a transverse drainage slope is set on the surface, and a sealing layer material is sprayed and a waterproof adhesive cloth is laid. Then, sufficient ballast is laid on the surface of the roadbed and the rails are installed on it. The vibratory motor is started again to drive the vibratory rod to vibrate continuously and apply it to the compacted roadbed with ballast, achieving the effect of compacting the roadbed and ballast. Then, the vibratory rod is removed and the original holes are filled with concrete. Then, the rails installed on the ballast surface are measured and calibrated to ensure that the installation of the rails fully meets the requirements. A freight train is placed on the rails and given sufficient weight to run back and forth between the rails under construction to test the reliability of the roadbed. After meeting the requirements, the test train can be removed, and the construction area can be unsealed and opened to traffic.

[0038] The foregoing has shown and described the basic principles, main features, and advantages of the present invention. It will be apparent to those skilled in the art that the invention is not limited to the details of the exemplary embodiments described above, and that the invention can be implemented in other specific forms without departing from its spirit or essential characteristics. Therefore, the embodiments should be considered illustrative and non-limiting in all respects, and the scope of the invention is defined by the appended claims rather than the foregoing description. Thus, all variations falling within the meaning and scope of equivalents of the claims are intended to be included within the scope of the invention. No reference numerals in the claims should be construed as limiting the scope of the claims.

[0039] Furthermore, it should be understood that although this specification describes embodiments, not every embodiment contains only one independent technical solution. This narrative style is merely for clarity. Those skilled in the art should consider the specification as a whole, and the technical solutions in each embodiment can also be appropriately combined to form other embodiments that can be understood by those skilled in the art.

Claims

1. A method for sealing the subgrade bed of a railway, characterized in that, Includes the following steps: Step 1: Close off and protect the construction section to prevent unauthorized personnel and animals from entering. At the same time, contact the station to coordinate with the vehicle and electrical departments and deliver cooperation notices. Simultaneously repair the ditches and slopes within the construction area. Step 2: Conduct on-site exploration of the roadbed to identify areas with high expansive soil content. Then, use excavators and other excavation tools to remove all the expansive soil. After that, backfill with sufficient cohesive soil that meets the moisture content requirements. Then, use a dynamic compaction machine to perform dynamic compaction on the roadbed section with backfilled cohesive soil and all other road sections, thereby improving the bearing capacity of the roadbed and reducing settlement. Step 3: Make columnar holes on both sides of the roadbed, insert vibrating rods and connect them to the vibrating motor, so that the vibrating rods are close to the inner surface of the holes, and then start the vibrating motor to drive the vibrating rods to vibrate continuously and act on the compacted roadbed, thus compacting the roadbed again. Step 4: Lay a layer of crushed stone and cement on the surface of the subgrade, set a transverse drainage slope on the surface of the subgrade, spray a sealing layer material, lay a waterproof adhesive cloth, and then lay a sufficient amount of ballast on the surface of the subgrade and install the rails on its surface. Step 5: Restart the vibratory motor to drive the vibratory rod to vibrate continuously and apply it to the compacted roadbed with ballast, so as to compact the roadbed and ballast. Then remove the vibratory rod and pour concrete into the original hole. After that, measure and calibrate the rails installed on the ballast surface to ensure that the installation of the rails fully meets the requirements. Step Six: Place a freight train on the rails and load it with sufficient weight. Let it travel back and forth between the rails under construction to test the reliability of the roadbed. Once the requirements are met, remove the test train, then lift the closure of the construction area and open it to traffic. In step two, the compaction time for the backfill soil should be much longer than that for the original soil, and the weighing capacity of the roadbed needs to be tested after compaction. The total duration of vibration in step three shall not be less than 24 hours, and the duration of each vibration shall not be less than 2 hours. When installing the rails in step four, manual backfilling of ballast is required at the beginning and end of the slope for transition. When the gantry crane lifts the rails, a ballast bag is symmetrically placed under each sleeper in the middle section, and ballast bags are piled up next to them and leveled. The total duration of vibration in step five shall not be less than 48 hours, and the duration of each vibration shall not be less than 3 hours.

2. The method for sealing the subgrade bed of a railway according to claim 1, characterized in that: The moisture content of the backfill soil in step two should not exceed 8%-12% of the total content of sandy soil and 12%-15% of the total content of silty clay.

3. The method for sealing the railway subgrade bed according to claim 1, characterized in that: The slope inclination angle of the drainage slope in step four should be between 4° and 10°.

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