Large-section metro underground excavation station top-lifting channel double-layer primary support arch structure
By adopting a double-layer primary support arch structure in the cantilevered passage of a large-section subway underground station, the problems of over-excavation and large backfill volumes in traditional construction methods were solved, a safe and fast construction process was achieved, and construction risks and environmental impacts were reduced.
Patent Information
- Application Number
- CN202422961754.5
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2024-12-02
- Publication Date
- 2025-09-26
- Estimated Expiration
- 2034-12-02
AI Technical Summary
Traditional cantilevered tunnel construction methods pose safety risks in the construction of large underground space structures. The amount of over-excavation and backfilling is large, which affects the construction progress and cost, and it is difficult to ensure the density and uniformity of the backfill material.
A double-layer primary arch structure is adopted for the cantilevered passage of a large-section subway underground station, including an arch frame layer and a main steel frame layer. Through the combination of portal steel frames and main steel frames, arch replacement construction is reduced, over-excavation and backfilling are reduced, and construction safety and construction period are ensured.
It has achieved safe and efficient construction under complex geological conditions, reduced construction risks, reduced construction noise and pollution, and improved construction efficiency and safety.
Smart Images
Figure CN223387342U_ABST
Abstract
Description
Technical Field
[0001] The utility model belongs to the technical field of tunnel construction and relates to a double-layer primary support arch structure of a cantilevered passage in a large-section underground excavation station of a subway. Background Art
[0002] With the acceleration of urbanization, subway construction, as a key means of alleviating urban traffic pressure, continues to expand in scale and speed. In the planning of major cities' subway networks, subway stations, as key connecting nodes, are crucial for the selection of their construction methods. This is particularly true in urban core areas, where complex surface environments, densely populated buildings, and heavy traffic make traditional open-cut methods unsuitable due to the significant impact on surface traffic and the large amount of demolition required. Therefore, underground excavation, with its advantages of minimal impact on the ground and flexible construction, has become the preferred method for urban subway station construction.
[0003] Concealed excavation stations typically access the main station area through pre-installed auxiliary passageways, a process that demands extremely high technical expertise. Especially for large underground structures like subway stations, safely and efficiently achieving the transition from auxiliary passageways to the main station area presents a major construction challenge. The construction of elevated and topped-out passageways is a critical step in this transition, requiring precise control of excavation height and width without compromising the stability of the existing ground structure to ensure smooth subsequent construction.
[0004] However, the roof conversion process is not easy, especially in areas with complex geological conditions, such as soft soil, aquifers, or interlaced rock strata. Improper construction methods can easily lead to safety risks such as tunnel roof collapse and groundwater leakage, which not only affect the construction progress but also endanger the safety of construction workers. Therefore, a scientific and reasonable construction plan is particularly important.
[0005] Traditional methods of cantilevered tunnel construction often result in the top height exceeding the design elevation of the main station tunnel, creating unnecessary space. This not only increases construction costs but also prolongs the construction period due to the large amount of plain concrete backfill required to eliminate gaps. Furthermore, over-excavation can lead to increased ground disturbance and increase the risk of ground instability. During the backfill process, ensuring the density and uniformity of the backfill material to avoid voids and uneven settlement is also a key challenge in controlling construction technology.
[0006] In view of the above problems, the industry needs to explore innovative construction technologies and, through technological innovation, realize the refinement and intelligence of the construction of elevated roof passages in underground excavation stations, ensure the safety, efficiency and environmental protection of subway station construction, and provide more solid technical support for the development and utilization of urban underground space. Utility Model Content
[0007] In view of this, the purpose of the present invention is to provide a double-layer primary support arch structure for a large-section subway underground station cantilevered passage, which fully utilizes the primary support structure of the passage, reduces arch replacement construction, reduces over-excavation and backfilling, ensures the safety of the cantilevered passage and the construction period, and makes the construction process high-quality, fast and controllable.
[0008] In order to achieve the above-mentioned purpose, the present invention provides the following technical solutions:
[0009] A double-layer primary arch structure for a cantilevered passage in a large-section underground tunnel station comprises a plurality of arch frame layers closely arranged in the cantilevered passage along the length of the cantilevered passage, a main steel frame layer being arranged between the arch frame layers and the cantilevered passage, and the main steel frame layer being fixed to the arch frame layers to form a double-layer primary arch structure;
[0010] The main steel frame layer includes a portal steel frame, a main steel frame and a crossbeam that are sequentially connected from top to bottom. The portal steel frame includes two first columns that are relatively arranged. The crossbeam is arranged between adjacent first columns. The crossbeam is fixed to the arch frame layer through a second column. The main steel frame is fixed to the crossbeam through an oblique steel plate, and the portal steel frame is fixedly connected to the main steel frame. Several portal steel frames are sequentially arranged along the length direction of the cantilevered passage, and the setting height of the portal steel frame matches the height of the cantilevered passage.
[0011] Optionally, the oblique steel plate includes a horizontal surface and an oblique surface that are intersecting with each other, the horizontal surface is arranged on the crossbeam, and the oblique surface is in contact with one end of the main steel frame.
[0012] Optionally, the portal steel frame and the crossbeam are arranged along the width direction of the cantilevered channel, and the main steel frame and the second column are arranged in sequence along the width direction of the cantilevered channel; each main steel frame is arranged at an angle, and the lower end is fixedly connected to the oblique steel plate.
[0013] Optionally, the first column and / or the second column is a vertical steel frame.
[0014] Optionally, a single-layer steel mesh is hung on one side of the portal steel frame close to the main steel frame, and C25 early-strength concrete is sprayed on the steel mesh.
[0015] Optionally, locking foot anchor rod groups are respectively provided at both ends and the middle of the portal steel frame, and at the middle and bottom of the first column.
[0016] Optionally, each of the locking foot anchor rod groups includes two locking foot anchor rods inserted into the inner wall of the tunnel at different angles.
[0017] Optionally, the locking foot anchor rod group arranged in the middle of the first column is located on the tunnel step dividing line.
[0018] Optionally, the arch frame layer includes at least 3 arch frames that are closely spaced radially along the cantilevered passage, with a close spacing of 1.2m to 1.5m.
[0019] Optionally, an adjustable supporting device is provided at the bottom of the column.
[0020] The beneficial effects of the present invention are:
[0021] This utility model is suitable for tunnel construction that utilizes an auxiliary channel to enter a large-section dark-excavated tunnel for process conversion. In the construction of a dark-excavated large-section subway station cantilever channel, by optimizing the excavation process of the construction channel entering the station main tunnel cantilever channel, a double-layer primary support arch is adopted, namely a portal steel frame + main steel frame support, which has a larger cross-sectional size and stronger bearing capacity. This fully utilizes the channel primary support structure, reduces arch replacement construction, reduces over-excavation and backfilling, ensures the safety of the station cantilever channel and the construction period, and ensures that the construction process is in a high-quality, rapid and controllable state, which has certain promotion value. This utility model adopts a non-blasting excavation method and uses a breaker hammer for excavation operations, reducing the impact of construction on the surrounding environment. It has the characteristics of high safety, low noise and low pollution.
[0022] Other advantages, objectives, and features of the present invention will be described in detail in the following description and, to some extent, will be apparent to those skilled in the art upon examination and study of the following or may be learned from practice of the present invention. The objectives and other advantages of the present invention may be realized and obtained through the following description. BRIEF DESCRIPTION OF THE DRAWINGS
[0023] In order to make the purpose, technical solutions and advantages of the present invention more clear, the present invention will be described in detail below with reference to the accompanying drawings, in which:
[0024] Figure 1 Schematic diagram of the double-layer primary support structure;
[0025] Figure 2 for Figure 1 Side view of the structure of the middle main steel frame layer;
[0026] Figure 3 This is a schematic diagram of a portal steel frame;
[0027] Figure 4 A flow chart of construction steps.
[0028] Figure numerals: 1 arch frame layer, 2 main steel frame layer, 21 portal steel frame, 22 main steel frame, 23 crossbeam, 24 first column, 25 second column, 26 oblique steel plate, 27 locking foot anchor rod group, 28 steel mesh. DETAILED DESCRIPTION
[0029] The following describes the embodiments of the present invention through specific examples. Those skilled in the art can easily understand the other advantages and effects of the present invention from the content disclosed in this specification. The present invention can also be implemented or applied through other different specific embodiments. The details in this specification can also be modified or changed based on different viewpoints and applications without departing from the spirit of the present invention. It should be noted that the illustrations provided in the following embodiments are only schematic illustrations of the basic concept of the present invention. The following embodiments and the features in the embodiments can be combined with each other without conflict.
[0030] Among them, the accompanying drawings are only for illustrative purposes and represent only schematic diagrams rather than actual pictures, and should not be understood as limiting the present invention. In order to better illustrate the embodiments of the present invention, some parts of the accompanying drawings may be omitted, enlarged or reduced, and do not represent the size of the actual product. For those skilled in the art, it is understandable that some well-known structures and their descriptions may be omitted in the accompanying drawings.
[0031] The same or similar numbers in the drawings of the embodiments of the present invention correspond to the same or similar parts; in the description of the present invention, it should be understood that if there are terms such as "upper", "lower", "left", "right", "front", "back", etc. indicating directions or positional relationships, they are based on the directions or positional relationships shown in the drawings. This is only for the convenience of describing the present invention and simplifying the description, and does not indicate or imply that the device or element referred to must have a specific direction, be constructed and operated in a specific direction. Therefore, the terms describing the positional relationship in the drawings are only used for illustrative purposes and cannot be understood as limiting the present invention. For ordinary technicians in this field, the specific meanings of the above terms can be understood according to specific circumstances.
[0032] See also Figures 1 to 4 This is a double-layer primary arch structure for a cantilevered passageway in a large-section underground subway station. It includes several arch frame layers 1 densely arranged along the length of the cantilevered passageway. A main steel frame layer 2 is located between the arch frame layer 1 and the cantilevered passageway. The main steel frame layer 2 is fixed to the arch frame layer 1, forming a double-layer primary arch structure. The main steel frame layer 2 includes a portal steel frame 21, a main steel frame 22, and a crossbeam 23, which are connected in sequence from top to bottom. The portal steel frame 21 includes two opposing first columns 24. The crossbeam 23 is located between adjacent first columns 24 and is fixed to the arch frame layer 1 via a second column 25. The main steel frame 22 is fixed to the crossbeam 23 via an inclined steel plate 26. The portal steel frame 21 and the main steel frame 22 are fixedly connected. The portal steel frame 21 layer and the main arch frame layer 1 form a double-layer primary arch structure to reduce arch replacement construction and the amount of over-excavation and backfill.
[0033] The oblique steel plate 26 includes a horizontal surface and an oblique surface that intersect each other. The horizontal surface is provided on the crossbeam 23 , and the oblique surface is in contact with one end of the main steel frame 22 .
[0034] The portal steel frame 21 and the crossbeam 23 are arranged along the width direction of the cantilevered passage, and several main steel frames 22 and second columns 25 are arranged in sequence along the width direction of the cantilevered passage; each of the main steel frames 22 is arranged at an angle, and the lower end is fixedly connected to the inclined steel plate 26. A single-layer steel mesh 28 is hung on the side of the portal steel frame 21 close to the main steel frame 22, and C25 early-strength concrete is sprayed on the steel mesh 28. Locking foot anchor rod groups 27 are respectively provided at both ends and the middle of the portal steel frame 21, and in the middle and bottom of the first column 24. Each locking foot anchor rod group 27 includes two locking foot anchor rods inserted into the inner wall of the tunnel at different angles. The locking foot anchor rod group 27 arranged in the middle of the first column 24 is located on the tunnel step dividing line.
[0035] The first column 24 and / or the second column 25 are vertical steel frames. Adjustable support devices are provided at the bottom of the columns to adapt to the foundation conditions under different geological conditions.
[0036] The arch frame layer 1 includes at least 3 arch frames closely arranged along the radial direction of the cantilevered passage, with a close spacing of 1.2m to 1.5m, so as to enhance the structural stability.
[0037] The double-layer primary support arch structure of the utility model is suitable for dark-excavated large-section tunnel projects with complex geological conditions and high requirements on the impact on the surrounding environment. It can significantly reduce construction risks and improve construction efficiency.
[0038] The construction method of the double-layer primary support arch structure of the cantilevered passage of a large-section underground excavation station using any of the above methods comprises the following steps:
[0039] S1: First, prepare for the layout of water pipes, power facilities, and ventilation facilities. Then, proceed to the top-lift construction. Excavation is carried out from the auxiliary channel to the interface of the main tunnel. A modified 485 short-arm breaker hammer is used during excavation. After excavation is completed, three arch frames are densely arranged at the starting position of the top-lift portal section. Steel plates are welded to the top of the three arch frames. The main steel frame 22 is then embedded between the steel plates and the top of the excavated tunnel. The base is placed on the oblique steel plate 26 on the top of the steel frame and filled with concrete for dense support.
[0040] S2: Construct the upper steps of the main tunnel. Several portal steel frames 21 are erected in sequence according to the changes in the excavation contour line. The portal steel frames 21 are connected by steel bars. The top excavation contour line is raised from the auxiliary channel at an angle of 15° to the top of the main tunnel arch.
[0041] After the portal steel frames 21 are erected, the first layer of initial support is promptly applied. The spacing between the portal steel frames 21 in the main tunnel of the cantilevered passage is 0.75m. The top excavation contour line is raised from the top of the auxiliary passage at a 15° angle to the designed station arch top. The height of the portal steel frames 21, which are sequentially installed along the length of the cantilevered passage, matches the height of the cantilevered passage and changes with the height of the cantilevered passage. Then, according to the outer contour line of the excavation of the main arch of the station, it is set up 320mm outward, and the rectangular channel within the cross-section of the station is excavated in sections according to the step method. During the construction process, it is necessary to erect a portal steel frame 21 according to the height change. The portal steel frame 21 is assembled according to the construction situation. The portal frame is pre-assembled for overall installation, and then the portal frame is fixed in a specific position, and the portal frames are connected with steel bars; the portal frame is installed in steps, first fixing the columns, and then installing the upper components in turn. After the assembly is completed, the steel bars connect the adjacent portals, and the two I-beams of the arch are connected with Φ22 steel bars, with a circumferential spacing of 1m. The I-beams are welded to the connecting steel plates, and the connecting steel plates are connected with M20 bolts.
[0042] S3: After the portal steel frame 21 is installed in the cantilever tunnel, anchor spraying support is carried out, and the initial anchor support is carried out with the main tunnel, including the use of hollow grouting anchors for support;
[0043] S4, after the overall construction of the cantilevered passage is completed, the SY155 breaker hammer is used to break the sprayed concrete inside the portal steel frame 21.
[0044] S5, the main steel frame layer 2 of the main tunnel is constructed. The main steel frame layer 2 is supported on three closely spaced steel frames and firmly welded to the portal steel frame 21 through the inclined steel plates 26. At the same time, a locking anchor group 27 is installed on the portal steel frame 21, and a steel mesh 28 is hung. A wet spraying robot is used to spray C25 early-strength concrete on the steel mesh 28 to ensure the stability of the steel frame.
[0045] S6. After the deformation, support, settlement and safety monitoring data are stable, the main tunnel excavation sequence is followed to remove the portal steel frame 21 columns in sequence, construct the main tunnel top arch layer and spray concrete, and firmly connect the main tunnel top arch layer with the main steel frame layer 2.
[0046] This utility model is particularly suitable for large-section, dark-excavated tunnel projects with complex geological conditions and high requirements for the construction environment. Systematic safety and environmental protection measures are implemented during construction, including setting up warning signs, strengthening monitoring and measurement, and rationally arranging construction time to reduce noise and dust pollution.
[0047] Finally, it should be noted that the above embodiments are only used to illustrate the technical solution of the utility model and are not limiting. Although the utility model is described in detail with reference to the preferred embodiments, ordinary technicians in this field should understand that the technical solution of the utility model can be modified or replaced by equivalents without departing from the purpose and scope of the technical solution, which should be included in the scope of the claims of the utility model.
Claims
1. A double-layer primary arch structure for a cantilevered passageway in a large-section underground subway station, characterized by: It comprises a plurality of arch frame layers (1) which are closely arranged in the cantilevered passage along the length direction of the cantilevered passage, a main steel frame layer (2) is arranged between the arch frame layer (1) and the cantilevered passage, and the main steel frame layer (2) is fixed on the arch frame layer (1) to form a double-layer primary support arch structure; The main steel frame layer (2) includes a portal steel frame (21), a main steel frame (22) and a crossbeam (23) which are sequentially connected from top to bottom, the portal steel frame (21) includes two first columns (24) which are arranged opposite to each other, the crossbeam (23) is arranged between adjacent first columns (24), and the crossbeam (23) is fixed to the arch frame layer (1) through a second column (25); the main steel frame (22) is fixed to the crossbeam (23) through an oblique steel plate (26), and the portal steel frame (21) is fixedly connected to the main steel frame (22); a plurality of portal steel frames (21) are sequentially arranged along the length direction of the cantilevered passage, and the setting height of the portal steel frame (21) matches the height of the cantilevered passage.
2. The double-layer primary arch structure for a cantilevered passageway in a large-section underground tunnel station according to claim 1 is characterized in that: The oblique steel plate (26) comprises a horizontal surface and an oblique surface that intersect each other, the horizontal surface is arranged on the crossbeam (23), and the oblique surface is in contact with one end of the main steel frame (22).
3. The double-layer primary arch structure for a cantilevered passageway in a large-section underground tunnel station according to claim 1 is characterized in that: The portal steel frame (21) and the crossbeam (23) are arranged along the width direction of the cantilevered passage, and a plurality of the main steel frames (22) and the second upright columns (25) are arranged in sequence along the width direction of the cantilevered passage; each main steel frame (22) is arranged obliquely, and the lower end is fixedly connected to the oblique steel plate (26).
4. The double-layer primary arch structure for a cantilevered passageway in a large-section underground tunnel station according to claim 3 is characterized by: The first column (24) and / or the second column (25) are vertical steel frames.
5. The double-layer primary arch structure for a cantilevered passage in a large-section underground subway station according to claim 1 is characterized in that: A single-layer steel mesh (28) is hung on one side of the portal steel frame (21) close to the main steel frame (22), and C25 early-strength concrete is sprayed on the steel mesh (28).
6. The double-layer primary arch structure for a cantilevered passageway in a large-section underground tunnel station according to claim 1 is characterized by: The two ends and the middle of the portal steel frame (21), and the middle and the bottom of the first column (24) are respectively provided with locking foot anchor rod groups (27).
7. The double-layer primary arch structure for a cantilevered passageway in a large-section underground tunnel station according to claim 6 is characterized in that: Each locking foot anchor rod group (27) comprises two locking foot anchor rods inserted into the inner wall of the tunnel at different angles.
8. The double-layer primary arch structure for a cantilevered passage in a large-section underground subway station according to claim 6 is characterized by: The locking foot anchor rod group (27) arranged in the middle of the first column (24) is located on the tunnel step boundary line.
9. The double-layer primary arch structure for a cantilevered passage in a large-section underground subway station according to claim 1 is characterized by: The arch frame layer (1) comprises at least three arch frames closely spaced radially along the cantilevered passage, with a close spacing of 1.2m to 1.5m.
10. The double-layer primary arch structure for a cantilevered passage in a large-section underground tunnel station according to claim 1 is characterized in that: An adjustable supporting device is provided at the bottom of the column.