High fill roadbed system capable of being rapidly implemented in narrow space of busy trunk line and construction method

Abstract

According to the high-fill roadbed system capable of being rapidly implemented in the narrow space of the busy trunk line, fender posts are arranged along the periphery of a frame bridge construction foundation pit so as to support the area corresponding to pushing construction of a frame bridge, and a supporting roadbed is located in the area defined by the fender posts and is close to the pushing path of the frame bridge; steel supports are erected between the supporting roadbed and the fender posts so as to form an overhead area corresponding to a pushing path of the frame bridge; the steel sheet piles are located on the two sides of the supporting roadbed, cross beams corresponding to the steel sheet piles are arranged on the two sides of the supporting roadbed respectively, and the two cross beams are connected through prestressed tendons. In the construction process, an original railway roadbed serves as an independent support, pre-installation can be conducted before construction of the frame bridge, the total follow-up roadbed filling amount is reduced through reply of the roadbed supporting system, the construction influence on the outer side of the roadbed filling range is reduced, and the construction efficiency can be improved easily.

Description

Technical Field

[0001] This invention belongs to the technical field of railway subgrade construction, specifically relating to a high embankment subgrade system and construction method for rapid implementation in narrow spaces along busy trunk lines. Background Technology

[0002] In the construction of multi-span frame bridges on busy trunk railways, an overhead support system is typically used to ensure the safe passage of trains. However, during the conversion of the load-bearing system in the overhead jacking construction of busy trunk railways, it is often necessary to quickly fill the subgrade in a confined space. Since safety is of paramount importance on busy trunk railways, the confined space, the difficulty of subgrade filling, and the high requirements for filling quality make conventional overhead load-bearing systems pose certain safety risks. Without subgrade support, it is safer and more reliable. In addition, using I-beams for overhead construction requires large hoisting equipment, which places high demands on site size, foundation bearing capacity, and equipment positioning. These requirements cannot be met in confined spaces. Furthermore, the load-bearing system after the overhead construction can cause train swaying due to vibration after frequent passage of heavy-load trains, endangering the safety of railway operations.

[0003] Therefore, there is a need to provide an improved technical solution that addresses the shortcomings of the existing technology. Summary of the Invention

[0004] The purpose of this invention is to overcome the shortcomings of the prior art. This invention provides a high embankment subgrade system and construction method for rapid implementation in narrow spaces on busy trunk lines.

[0005] To achieve the above objectives, the present invention provides the following technical solution: A high embankment subgrade system for rapid implementation in narrow spaces along busy trunk lines includes: Retaining piles are arranged along the periphery of the construction pit of the frame bridge to support the area corresponding to the jacking construction of the frame bridge. A supporting roadbed is located within the area enclosed by the retaining piles and close to the jacking path of the frame bridge. A steel support is erected between the supporting roadbed and the retaining piles to form an elevated area corresponding to the jacking path of the frame bridge. Sheet piles are located on both sides of the supporting roadbed, and crossbeams corresponding to the sheet piles are provided on both sides of the supporting roadbed. The two crossbeams are connected by prestressed tendons. A jacking mechanism is located between the retaining piles and the corresponding sheet piles to provide support for the sheet piles.

[0006] Preferably, the top support mechanism includes a plurality of steel pipe columns spaced apart along the mileage direction of the roadbed, one end of each steel pipe column being supported by a steel pipe column base on the inner wall of the retaining pile, and the other end being supported by a crossbeam on the outer side of the steel sheet pile. The steel pipe column base is a double-I-beam extending horizontally along the inner wall of the retaining pile. Multiple adjusting ends corresponding to the steel pipe column are provided on the steel pipe column base. Each adjusting end includes an outer sleeve and an inner sleeve that are nested together. The outer sleeve is fixed to the end of the steel pipe column, and the inner sleeve is fixed to the steel pipe column base. A jacking cylinder is provided between the steel pipe column base and the end of the steel pipe column.

[0007] Preferably, a U-shaped pad is provided between the outer sleeve and the steel pipe column base.

[0008] Preferably, slopes are formed by excavation on both sides of the supporting roadbed, and slope protection structures are stacked at the slopes, with ramps provided on the outside of the slope protection structures.

[0009] Preferably, steps are provided on both sides of the supporting roadbed, located at the upper edge of the sheet piles, and the slope extends to the inner edge of the steps; The slope protection structure is stacked on the steps.

[0010] Preferably, the steel sheet piles corresponding to the jacking pit of the frame bridge are stacked with protective slopes.

[0011] A method for rapid construction of high embankment subgrades in narrow spaces along busy trunk railway lines, comprising: Step S1: Measure the area of ​​the frame bridge jacking construction area and drive retaining piles along the perimeter of the construction area. Step S2: Excavate the area inside the retaining piles to form a foundation pit. During the excavation process, reserve a supporting roadbed and pour the frame bridge inside the foundation pit. Step S3: Steel sheet piles are driven on both sides of the supporting roadbed, and crossbeams corresponding to the steel sheet piles are respectively provided on both sides of the supporting roadbed. The two crossbeams are connected by prestressed tendons. A top support mechanism is installed between the retaining piles and the corresponding sheet piles to provide support for the sheet piles. Step S4: A steel support is erected between the supporting roadbed and the retaining piles. After the frame bridge is poured and the jacking jacks are set up, the jacking path of the frame bridge under the steel support is excavated, and then the frame bridge is jacked. Step S5: After the frame bridge is pushed into place, the area under the steel support is backfilled and grouted for reinforcement, and the steel support, jacking mechanism and steel sheet piles are gradually removed.

[0012] Preferably, grouting reinforcement is carried out on the area corresponding to the supporting roadbed.

[0013] Preferably, multiple displacement monitoring points are set on the sheet piles, and the jacking mechanism is controlled based on the displacement monitoring points to control the displacement and deformation of the sheet piles caused by roadbed settlement.

[0014] Beneficial effects: By using the existing railway subgrade as an independent support during construction, the subgrade support system can be pre-installed before the frame bridge construction. This subgrade support system reduces the total amount of subsequent subgrade filling and reduces the impact on construction outside the subgrade filling area, which helps to speed up construction efficiency.

[0015] This embankment subgrade system can be implemented in the narrow space above busy trunk railway lines. Using this embankment subgrade system is applicable to the conversion of the load-bearing system during the jacking of bridges. It not only greatly improves the safety of railway operation, but also enhances the applicability of the embankment subgrade system, and can meet the railway department's requirements for safe construction. Attached Figure Description

[0016] The accompanying drawings, which form part of this application, are used to provide a further understanding of the invention. The illustrative embodiments of the invention and their descriptions are used to explain the invention and do not constitute an undue limitation of the invention. Wherein: Figure 1 This is a simplified top view of the roadbed system in a specific embodiment provided by the present invention; Figure 2 This is a simplified cross-sectional diagram of the roadbed system in a specific embodiment provided by the present invention; Figure 3 for Figure 1 Enlarged diagram of point A in the middle.

[0017] In the diagram: 1. Retaining pile; 2. Frame bridge; 3. Steel pipe column; 4. Steel sheet pile; 5. Steel pipe column base; 6. Crossbeam; 7. Adjustable end; 8. Supporting subgrade; 9. Prestressed tendon; 10. Protective slope; 11. Slope protection structure; 12. Pushing cylinder; 701. Outer sleeve; 702. Inner sleeve; 703. U-shaped pad. Detailed Implementation

[0018] The technical solutions in the embodiments of the present invention will be clearly and completely described below. Obviously, the described embodiments are only a part of the embodiments of the present invention, and not all of them. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention are within the scope of protection of the present invention.

[0019] In the description of this invention, the terms "longitudinal," "lateral," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," and "bottom," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing the invention and do not require the invention to be constructed and operated in a specific orientation; therefore, they should not be construed as limitations on the invention. The terms "connected" and "linked" used in this invention should be interpreted broadly. For example, they can refer to a fixed connection or a detachable connection; they can refer to a direct connection or an indirect connection through intermediate components. Those skilled in the art can understand the specific meaning of the above terms according to the specific circumstances.

[0020] The present invention will now be described in detail with reference to the accompanying drawings and embodiments. It should be noted that, unless otherwise specified, the embodiments and features described herein can be combined with each other.

[0021] like Figure 1-3 As shown, a high embankment subgrade system for rapid implementation in narrow spaces along busy trunk lines includes retaining piles 1, supporting subgrade 8, sheet piles 4, and a jacking mechanism. It is suitable for high embankment subgrade construction and frame bridge 2 jacking operations in narrow spaces. By forming a stable support system in the construction area, it provides safety assurance for the jacking of frame bridge 2 and high embankment subgrade construction.

[0022] The retaining piles 1 are arranged along the perimeter of the construction pit of the frame bridge 2. Any two adjacent retaining piles 1 interlock, forming a U-shaped protective structure for the corresponding construction pit. Alternatively, on the side where the jacking equipment is installed, no retaining piles 1 are installed, forming a C-shaped protection. This provides all-round support for the area corresponding to the jacking construction of the frame bridge 2, resisting the lateral pressure of the soil surrounding the pit and providing a safe working space. The retaining piles 1 are reinforced concrete cast-in-place piles, with a length of not less than 5m inserted into the bottom slab of the pit. The specific railway support body is the supporting subgrade 8 below. The supporting subgrade 8 is selected within the area enclosed by the retaining piles 1, close to the jacking path of the frame bridge 2, using the core bearing structure of the original subgrade to provide support for the jacking operation of the frame bridge 2. Furthermore, steel supports are erected between the supporting roadbed 8 and the retaining piles 1. The steel supports are made of high-strength I-beams and are firmly connected at both ends to the side of the supporting roadbed 8 and the inner wall of the retaining piles 1, respectively. Multiple cross braces are set between the steel supports on both sides. The cross braces pass under the railway guide rails or sleepers to form a ladder-shaped structure, which serves as the overhead area for the jacking path of the corresponding frame bridge 2, further improving the overall rigidity and stability of the entire support system.

[0023] To ensure the stability of the supporting roadbed 8, sheet piles 4 are installed on both sides of the supporting roadbed 8. The sheet piles 4 are symmetrically distributed to protect the soil on both sides of the supporting roadbed 8 and ensure the lateral stability of the supporting roadbed 8. Crossbeams 6 corresponding to the sheet piles 4 are installed on both sides of the supporting roadbed 8. The crossbeams 6 extend along the mileage direction of the supporting roadbed 8 and are made of double-I-beams. Corbels or three-piece supports are installed on the sheet piles 4 to support the crossbeams 6. The sheet piles 4 are inserted at least 3m below the bottom slab of the foundation pit. The two crossbeams 6 are connected by prestressed tendons 9. The prestressed tendons 9 are made of high-strength steel strands, which, after tensioning, can form a lateral preload on the supporting roadbed 8 to further constrain the deformation of the supporting roadbed 8. The prestressed tendons 9 are installed by drilling holes laterally. Furthermore, a jacking mechanism is provided between the retaining pile 1 and the corresponding sheet pile 4, so that the sheet pile 4 provides stable support force, resists the lateral soil pressure on the sheet pile 4, prevents the sheet pile 4 from deforming or displacing, and thus ensures the stability of the supporting subgrade 8 and the entire construction area, providing a safety guarantee for the jacking of the frame bridge 2 and the construction of the high embankment subgrade.

[0024] In this embodiment, multiple supporting mechanisms are installed on the other side of the foundation pit to support the sheet piles 4. The supporting mechanisms include multiple steel pipe columns 3 spaced apart along the mileage direction of the supporting roadbed 8. The steel pipe columns 3 are made of high-strength steel pipes. One end of the steel pipe column 3 is supported on the inner wall of the retaining pile 1 through the steel pipe column base 5, and the other end is supported on the crossbeam 6 on the outer side of the sheet pile 4, forming a force transmission system of "retaining pile 1 - steel pipe column base 5 - steel pipe column - crossbeam 6 - sheet pile 4". This system can effectively transfer the lateral force on the sheet pile 4 to the retaining pile 1, realize the reasonable transmission of force, and improve the stability of the support. The steel pipe column base 5 is a double-I-beam extending horizontally along the inner wall of the retaining pile 1. Corresponding steel brackets or triangular supports are installed on the retaining pile 1. Multiple adjusting ends 7 corresponding to the steel pipe columns 3 are provided on the steel pipe column base 5. Each adjusting end 7 includes an outer sleeve 701 and an inner sleeve 702 that are interlocked. Both the outer sleeve 701 and the inner sleeve 702 are made of steel pipe or double-channel steel, and their sizes are matched. The outer sleeve 701 is fixed to the end of the steel pipe column 3 by welding or bolting. The inner sleeve 702 is fixed to the steel pipe column base 5, also by welding or bolting. A jacking cylinder 12 is provided between the steel pipe column base 5 and the ends of the steel pipe columns 3. The jacking cylinder 12 can adjust the support force of the steel pipe column 3 and compensate for the deformation of the sheet pile 4 according to the actual needs during construction.

[0025] No fewer than two adjusting ends 7 are evenly distributed around the circumference of the steel pipe column 3, and the lifting cylinder is located at the axis of the steel pipe column 3.

[0026] Furthermore, a U-shaped pad 703 is provided between the outer sleeve 701 and the steel pipe column base 5. The U-shaped pad 703 is made of high-strength steel and is upside down on the inner sleeve 702. Its shape is adapted to the contact part between the outer sleeve 701 and the steel pipe column base 5. The number or thickness of the U-shaped pad 703 can be adjusted as needed, thereby reducing the force on the jacking cylinder 12 during construction and improving the support reliability and service life of the jacking mechanism.

[0027] Slopes are formed by excavation on both sides of the supporting roadbed 8. The slope of the slope is determined according to the properties of the soil and the size of the construction pit. A slope protection structure 11 is piled up at the slope. The slope protection structure 11 uses sandbags. A slope is provided on the outside of the slope protection structure 11 to disperse the soil pressure on the slope and improve the protection effect.

[0028] In this embodiment, steps are provided on both sides of the roadbed along the upper edge of the sheet piles 4. The steps provide a supporting foundation for the slope protection structure 11. The slope extends to the inner edge of the steps, and its width can be adjusted according to the slope design and construction requirements. The slope protection structure 11 is stacked on the steps, thereby limiting the slope protection structure 11 and preventing it from sliding.

[0029] A protective slope 10 is stacked outside the sheet piles 4 corresponding to the jacking pit of the frame bridge 2. The protective slope 10 can further resist the lateral pressure of the soil outside the sheet piles 4 and assist the sheet piles 4 in achieving lateral protection. The protective slope 10 can also be formed by stacking sandbags.

[0030] In another embodiment, this application also provides a method for the rapid construction of high embankment subgrades in narrow spaces along busy main railway lines, comprising the following steps: Step S1: Measure the construction area of ​​the frame bridge 2 to accurately determine the boundary of the construction area, the excavation depth of the foundation pit, the location of the retaining piles 1, and other parameters. Then, drive the retaining piles 1 around the construction area. The retaining piles 1 are constructed using the bored pile construction process. The piles are driven in an alternating manner. Only after the concrete strength of the retaining piles 1 reaches more than 80% of the design strength can the next construction process begin.

[0031] Step S2: The area inside the retaining pile 1 is excavated in layers to form a construction pit. During the excavation process, the excavation speed and slope are strictly controlled. The excavation leaves room for the supporting roadbed 8. After the pit is excavated to the design elevation, the bottom of the pit is leveled and compacted. The sliding base plate of the frame bridge 2 is poured in the pit. Then, the reinforcement of the frame bridge 2 is tied, the formwork is erected, and the concrete is poured. After the concrete of the frame bridge 2 is poured, the curing work is carried out.

[0032] Step S3: Steel sheet piles 4 are driven into the excavated reserved section, corresponding to both sides of the supporting roadbed 8. After the steel sheet piles 4 are driven, crossbeams 6 corresponding to the steel sheet piles 4 are installed on both sides of the supporting roadbed 8. Holes are drilled horizontally using a drilling rig, and the prestressed tendons 9 pass through the drilled holes, with both ends connected to the crossbeams 6 on both sides. After the prestressed tendons 9 are tensioned to the design stress, anchoring is performed. Specifically, both ends of the prestressed tendons 9 pass through the crossbeams 6 and are connected to anchor plates.

[0033] A jacking mechanism is set up between the retaining pile 1 and the corresponding sheet pile 4. The steel pipe column base 5, steel pipe column 3, adjusting end 7 and jacking cylinder 12 are installed to ensure that all components are firmly connected. After the jacking cylinder 12 is installed in place, a trial run is carried out to check the working performance of the jacking mechanism and ensure that it can provide support force normally.

[0034] Step S4: Steel supports are erected between the supporting roadbed 8 and the retaining piles 1. After the frame bridge 2 is poured and the jacking jacks are installed, the jacking path of the frame bridge 2 under the steel supports is excavated, and then the frame bridge 2 is jacked. High-strength I-beams are used to erect steel supports between the supporting roadbed 8 and the retaining piles 1. Both ends are securely connected to the upper surface of the supporting roadbed 8 and the top of the retaining piles 1 respectively, using bolts or anchors. After the steel supports are installed, cross bracing is installed between the two steel supports to suspend the jacking path. Once the concrete strength of frame bridge 2 reaches 100% of the design strength and the jacking jacks are installed, the jacking path of frame bridge 2 under the steel support is excavated. During the excavation, protective measures are taken to prevent soil collapse. After the excavation is completed, the jacking jacks and jacking mechanism are started to carry out the jacking operation of frame bridge 2. During the jacking process, the displacement and attitude of frame bridge 2, as well as the deformation of the support system, are monitored in real time. The jacking speed and jacking force are adjusted in a timely manner based on the monitoring data to ensure that frame bridge 2 is jacked into place and its attitude meets the design requirements.

[0035] Step S5: After the frame bridge 2 is pushed into place, backfill and grout the area below the steel support, and gradually dismantle the steel support, jacking mechanism, and sheet piles 4. After the frame bridge 2 is pushed into place, backfill the area below the steel support and between the frame bridge 2 in layers. The backfill material is well-graded crushed stone or plain soil. After backfilling, grout the backfilled area for reinforcement. Cement mortar is used as the grout material (or, if the gap between the frame bridge 2 and the excavated area is small, grouting can be carried out directly) to improve the bearing capacity and stability of the roadbed. After the grout strength reaches the design requirements, gradually dismantle the steel support, jacking mechanism, and sheet piles 4. During the dismantling process, follow the principle of "support first, then dismantle; dismantle in sections and areas" to avoid dismantling too much at once and causing structural instability. Clean and recycle the dismantled equipment for future reuse.

[0036] In step S2, grouting reinforcement is carried out on the area corresponding to the supporting subgrade 8. High-pressure grouting technology is used for grouting, and the grouting holes are arranged in a quincunx pattern. The grouting depth and grouting pressure meet the design requirements. Grouting reinforcement can improve the bearing capacity of the soil under the supporting subgrade 8, reduce the subgrade settlement and deformation, ensure the stability of the supporting subgrade 8, and meet the construction requirements of high embankment subgrades.

[0037] Furthermore, a corresponding steel support groove is opened above the supporting roadbed 8, and concrete is poured on the basis of the groove to provide stable support for the steel support.

[0038] Furthermore, during the construction process from steps S3 to S5, multiple displacement monitoring points are set on the sheet piles 4. These monitoring points are evenly distributed along the height and mileage directions of the sheet piles 4. Professional monitoring equipment is used to monitor the displacement and deformation of the sheet piles 4 in real time, and the monitoring data is fed back to the construction control center in real time. Based on the monitoring data from the displacement monitoring points, the jacking force of the jacking mechanism is adjusted in a timely manner to control the displacement and deformation of the sheet piles 4 caused by roadbed settlement, ensuring that the displacement of the sheet piles 4 is controlled within the design allowable range, thus guaranteeing construction safety and project quality.

[0039] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention shall be within the scope of protection of the pending claims of the present invention.

Claims

1. A high embankment subgrade system for rapid implementation in narrow spaces along busy trunk lines, characterized in that, include: Retaining piles are arranged along the periphery of the construction pit of the frame bridge to support the area corresponding to the jacking construction of the frame bridge. A supporting roadbed is located within the area enclosed by the retaining piles and close to the jacking path of the frame bridge. A steel support is erected between the supporting roadbed and the retaining piles to form an elevated area corresponding to the jacking path of the frame bridge. Sheet piles are located on both sides of the supporting roadbed, and crossbeams corresponding to the sheet piles are provided on both sides of the supporting roadbed. The two crossbeams are connected by prestressed tendons. A jacking mechanism is located between the retaining piles and the corresponding sheet piles to provide support for the sheet piles.

2. The high embankment subgrade system for rapid implementation in narrow spaces along busy trunk railways according to claim 1, characterized in that, The top support mechanism includes a plurality of steel pipe columns spaced apart along the mileage direction of the roadbed. One end of each steel pipe column is supported by a steel pipe column base on the inner wall of the retaining pile, and the other end is supported by a crossbeam on the outer side of the steel sheet pile. The steel pipe column base is a double-I-beam extending horizontally along the inner wall of the retaining pile. Multiple adjusting ends corresponding to the steel pipe column are provided on the steel pipe column base. Each adjusting end includes an outer sleeve and an inner sleeve that are nested together. The outer sleeve is fixed to the end of the steel pipe column, and the inner sleeve is fixed to the steel pipe column base. A jacking cylinder is provided between the steel pipe column base and the end of the steel pipe column.

3. The high embankment subgrade system for rapid implementation in narrow spaces along busy trunk railways according to claim 2, characterized in that, A U-shaped pad is provided between the outer sleeve and the steel pipe column base.

4. The high embankment subgrade system for rapid implementation in narrow spaces along busy trunk railways according to claim 1, characterized in that, Slopes are formed by excavation on both sides of the supporting roadbed, and slope protection structures are piled up at the slopes. A ramp is provided on the outside of the slope protection structures.

5. The high embankment subgrade system for rapid implementation in narrow spaces along busy trunk railways according to claim 4, characterized in that, The roadbed is supported by steps on both sides located at the upper edge of the sheet piles, and the slope extends to the inner edge of the steps; The slope protection structure is stacked on the steps.

6. The high embankment subgrade system for rapid implementation in narrow spaces along busy trunk railways according to claim 1, characterized in that, The steel sheet piles corresponding to the jacking pit of the frame bridge are stacked with protective slopes on the outside.

7. A method for rapid construction of high embankment subgrade in narrow spaces along busy trunk railway lines, characterized in that, include: Step S1: Measure the area of ​​the frame bridge jacking construction area and drive retaining piles along the perimeter of the construction area. Step S2: Excavate the area inside the retaining piles to form a foundation pit. During the excavation process, reserve a supporting roadbed and pour the frame bridge inside the foundation pit. Step S3: Steel sheet piles are driven on both sides of the supporting roadbed, and crossbeams corresponding to the steel sheet piles are respectively provided on both sides of the supporting roadbed. The two crossbeams are connected by prestressed tendons. A top support mechanism is installed between the retaining piles and the corresponding sheet piles to provide support for the sheet piles. Step S4: A steel support is erected between the supporting roadbed and the retaining piles. After the frame bridge is poured and the jacking jacks are set up, the jacking path of the frame bridge under the steel support is excavated, and then the frame bridge is jacked. Step S5: After the frame bridge is pushed into place, the area under the steel support is backfilled and grouted for reinforcement, and the steel support, jacking mechanism and steel sheet piles are gradually removed.

8. The method for rapid construction of high embankment subgrade in narrow spaces on busy trunk railways according to claim 7, characterized in that, Grouting reinforcement was carried out on the corresponding area of ​​the supporting roadbed.

9. The method for rapid construction of high embankment subgrade in narrow spaces on busy trunk railways according to claim 7, characterized in that, Multiple displacement monitoring points are set on the sheet piles, and the top support mechanism is controlled based on the displacement monitoring points to control the displacement and deformation of the sheet piles caused by roadbed settlement.

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