Roadbed structure suitable for being used above soft soil stratum subway tunnel

Abstract

The utility model provides a roadbed structure suitable for being used above a soft soil stratum subway tunnel, which comprises a box type foundation with the lower part positioned below a ground line, a medium-coarse sand layer arranged on the box type foundation, an EPS (Expandable Polystyrene) layer arranged above the medium-coarse sand layer, a metal pin embedded in the upper part of the box type foundation, an upper end of the metal pin being inserted into the EPS layer through the medium-coarse sand layer, a lower end of the metal pin being inserted into the EPS layer through the medium-coarse sand layer, and a lower end of the metal pin being inserted into the EPS layer through the medium-coarse sand layer. A retaining wall is arranged around the medium-coarse sand layer and the EPS layer, a pavement structure is laid on the EPS layer, and the side face of the pavement structure is fixedly connected with the retaining wall in an adjacent mode, the roadbed structure suitable for the upper portion of the soft soil stratum subway tunnel is provided, the requirement for the roadbed structure strength is met, meanwhile, the additional load above the subway tunnel is greatly reduced, and the construction cost is reduced. The problem of excessive settlement deformation of the subway tunnel is avoided, and the safety of the subway tunnel is ensured.

Description

Technical Field

[0001] The utility model relates to the technical field of municipal road construction, in particular to a roadbed structure suitable for above a subway tunnel in a soft soil layer. Background Art

[0002] Metro lines are mostly laid along urban roads (existing roads or planned roads). Due to the influence of construction sequence, it is inevitable that the subway tunnel laid under the planned road will be completed before the planned road. In this case, the backfilling of the planned road subgrade will generate additional loads on the subway tunnel, which may easily cause the subway tunnel to sink and deform. This unfavorable situation is particularly significant in soft soil layers. Therefore, in order to ensure the safety of subway tunnels, it is necessary to reduce the additional loads generated by the new subgrade above the subway tunnel in soft soil layers. Utility Model Content

[0003] The purpose of the utility model is to overcome the deficiencies of the above-mentioned prior art and provide a roadbed structure suitable for subway tunnels in soft soil layers, which can solve the problem that the additional load generated by the new roadbed above the subway tunnel in the soft soil layer easily causes the subway tunnel to settle and deform.

[0004] To this end, the utility model adopts the following technical solutions:

[0005] A roadbed structure suitable for use above a subway tunnel in soft soil comprises a box foundation whose lower portion is located below the ground line, a medium-coarse sand layer is provided on the box foundation, an EPS layer is provided on the medium-coarse sand layer, metal pins are pre-buried in the upper portion of the box foundation, upper ends of the metal pins pass through the medium-coarse sand layer and are inserted into the EPS layer, retaining walls are provided around the medium-coarse sand layer and the EPS layer, a pavement structure is laid on the EPS layer, and the side surfaces of the pavement structure are adjacently fixed to the retaining walls.

[0006] On the basis of adopting the above technical solutions, the present invention can also adopt the following further technical solutions, or use these further technical solutions in combination:

[0007] A drainage pipe is pre-buried in the lower part of the retaining wall, one end of the drainage pipe is connected to the outside, and the other end of the drainage pipe is connected to the medium-coarse sand layer.

[0008] A reinforced concrete slab is cast between the pavement structure and the EPS layer.

[0009] The EPS layer is composed of a plurality of EPS blocks.

[0010] The EPS blocks adjacent to each other are arranged in a staggered manner.

[0011] A claw-type metal connection piece is fixed between two adjacent EPS blocks.

[0012] A claw-shaped metal connecting piece is fixed between the reinforced concrete slab and the EPS layer thereunder.

[0013] The bottom surface of the box-type foundation is a horizontal plane, and the top surface of the box-type foundation is consistent with the longitudinal and transverse slopes of the pavement structure. The pavement structure is symmetrical about the center line of the designed road and slopes down from the middle to both sides.

[0014] Compared with the prior art, the utility model has the following advantages and beneficial effects: a roadbed structure suitable for subway tunnels in soft soil is proposed, which meets the requirements of roadbed structure strength, and at the same time greatly reduces the additional load above the subway tunnel, avoids the problem of excessive settlement and deformation of the subway tunnel, and ensures the safety of the subway tunnel. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 It is a schematic diagram of the elevation structure of the utility model. DETAILED DESCRIPTION

[0016] In order to enable those skilled in the art to better understand the technical solution of the present utility model, the preferred implementation scheme of the present utility model is described below in conjunction with specific embodiments. Examples of the embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals throughout represent elements with the same or similar functions. However, it should be understood that the accompanying drawings are only used for illustrative purposes and cannot be understood as limitations on the present utility model. In order to better illustrate the present embodiment, 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 in the accompanying drawings may be omitted, and the positional relationship described in the accompanying drawings is only used for illustrative purposes and cannot be understood as limitations on the present utility model.

[0017] The present invention is further described below in conjunction with the accompanying drawings and embodiments, but they are not intended to limit the present invention.

[0018] The utility model provides a roadbed structure suitable for above a subway tunnel in a soft soil layer, comprising a box-type foundation 1 whose lower part is located below a ground line 10, a medium-coarse sand layer 2 is provided on the box-type foundation 1, an EPS layer 4 is provided on the medium-coarse sand layer 2, metal pins 3 are pre-buried in the upper part of the box-type foundation 1, the upper ends of the metal pins 3 pass through the medium-coarse sand layer 2 and are inserted into the EPS layer, retaining walls 9 are provided around the medium-coarse sand layer 2 and the EPS layer 4, a pavement structure 7 is laid on the EPS layer 4, and the side surfaces of the pavement structure 7 are adjacent to and fixed to the retaining wall 9.

[0019] In this embodiment, the mud volume of the medium-coarse sand layer 2 is not more than 3%, and the thickness is required to be uniform, the surface is flat, and the top surface flatness thickness error is ±10mm;

[0020] The size of the EPS block is 300cm×124cm×63cm, and the bulk density is 35KG / m³; the material of the EPS block must meet the requirements of 10% strain compressive strength of not less than 110kpa, flexural strength of not less than 150kpa, compression modulus of not less than 3.5Mpa, and 7d volume water absorption rate of not more than 1.5%; the material of the EPS block should also have self-extinguishing properties when burning;

[0021] When laying EPS blocks, they can be laid from left to right, with the upper and lower adjacent EPS blocks staggered by half a block width. If the last block is of irregular size, the width of the irregular size block must not be less than 25cm.

[0022] like Figure 1 As shown, the bottom plate 11 of the box foundation 1 extends outward compared to the box body 12, exceeding the width of the pavement structure 7 and the retaining wall 9. By setting the box foundation 1 as a part of the roadbed structure, the additional load of the roadbed structure above the subway tunnel is reduced, and the groundwater is prevented from directly acting on the EPS layer 4, which plays a role in avoiding excessive settlement and deformation of the subway tunnel, reducing investment and ensuring the stability of the EPS layer roadbed structure. The bottom plate 11 of the box foundation 1 extends outward to resist the rise of groundwater level and avoid the adverse effect of the roadbed floating during flood disasters, which plays a role in ensuring the overall stability and safety of the roadbed and ensuring driving comfort. The retaining wall 9 above the box foundation 1 is flush with the outside of its box body 12.

[0023] A drainage pipe 8 is pre-buried in the lower part of the retaining wall 9 , one end of the drainage pipe 8 is connected to the outside, and the other end of the drainage pipe 8 is connected to the medium-coarse sand layer 2 .

[0024] The drainage pipe 8 in this embodiment is a UPVC pipe with a diameter of 5 cm, and the pipe mouth is flush with the inside of the retaining wall 9. If the control elevation is lower than the original ground elevation, the drainage pipe 8 can be connected to the existing rainwater inspection well.

[0025] A reinforced concrete slab 6 is cast between the pavement structure 7 and the EPS layer 4 .

[0026] The EPS layer 4 is composed of a plurality of EPS blocks.

[0027] The upper and lower adjacent EPS blocks are arranged in a staggered manner.

[0028] A claw-type metal connecting piece 5 is fixed between two adjacent EPS blocks.

[0029] like Figure 1 As shown, the upper end of the metal pin 3 is only inserted into the lowest EPS block in the EPS layer, wherein a metal pin 3 is inserted into each of the two ends of each EPS block.

[0030] A claw-shaped metal connecting piece 5 is fixed between the reinforced concrete slab 6 and the EPS layer 4 therebelow.

[0031] The bottom surface of the box foundation 1 is a horizontal plane, and the top surface of the box foundation 1 is consistent with the longitudinal and transverse slopes of the pavement structure 7. The pavement structure 7 is symmetrical about the center line of the designed road and slopes down from the middle to both sides.

[0032] Before implementing the planned road subgrade backfill project above the subway tunnel in soft soil, it is necessary to evaluate the current status of the subway tunnel and the impact of the subgrade backfill project above it on the subway tunnel, and propose deformation control standards for the impact of the subgrade backfill construction on the subway tunnel. According to the deformation direction and deformation size of the subway tunnel obtained by the assessment, combined with the geology of the subway tunnel, the surrounding environment, the design and construction plan of the planned road, etc., determine scientific and reasonable subgrade backfill steps.

[0033] The utility model is suitable for the construction steps of a roadbed structure above a subway tunnel in soft soil layer as follows:

[0034] Surrounding environment survey → cleaning of surface soil → construction of box foundation 1 and retaining wall 9 → backfilling of medium-coarse sand layer 2 → installation of EPS layer 4 → construction of reinforced concrete slab 6 → construction of pavement structure 7; the specific steps are:

[0035] 1) Surrounding environment survey: clarify the engineering geology, existing structures and surrounding environment. Existing structures refer to the existing subway tunnels nearby (including the location, structure size, burial depth and existing deformation of the subway tunnels). The surrounding environment refers to the topography, existing pipelines (if any) and existing buildings (if any) around the proposed site of the subway tunnel.

[0036] 2) Surface cleaning: After the surrounding environment survey is completed, the construction enclosure is built, and the vegetation and loose soil on the ground inside the enclosure are removed. After the surface is cleaned, mechanical compaction and site leveling are used; after the surface is cleaned, a ground line 10 appears.

[0037] 3) Construct box foundation 1 and side retaining wall 9: Excavate the box foundation 1. After excavating to the design elevation, construct box foundation 1 at 0.5~1m (above the groundwater level). The bottom surface of the box foundation should exceed the backfill width of the ground roadbed. The bottom plate of the box foundation 1 has no slope, and the longitudinal and transverse slopes of the top plate are consistent with the pavement structure. Before pouring the concrete of the top plate of the box foundation 1, metal pins 3 should be embedded as required by the design. After the strength of the top plate of the box foundation 1 reaches the design requirements, continue to construct the retaining wall 9. Before pouring the concrete of the retaining wall 9, the drainage pipe 8 should be embedded as required by the design.

[0038] 4) Backfilling the medium-coarse sand layer 2: After the strength of the box foundation and the retaining wall reaches the design requirements, a medium-coarse sand layer 2 with a thickness of 20 cm is laid on the inner side of the retaining wall 9 for leveling and drainage.

[0039] 5) Install EPS layer 4: The bottom EPS block is fixed on the metal pin 3. At the same time, the adjacent EPS blocks are fixed with claw-type metal connectors 5; EPS blocks are laid in a staggered manner, and when cutting is required, electric heating wire should be used for cutting. When there are gaps and height differences between blocks, and when there are gaps between blocks and structures, cement mortar should be used for leveling and filling;

[0040] 6) Construction of reinforced concrete slab: A layer of cast-in-place reinforced concrete slab 6 with a thickness of 18 cm is constructed on the top of the EPS block layer; the reinforced concrete slab adopts C30 concrete, and a layer of steel mesh is set at the bottom of the slab. The steel bar specifications and mesh size are determined according to the design requirements;

[0041] 7) Construction of pavement structure: After the strength of the reinforced concrete slab meets the requirements, the pavement structure layer 7 is constructed.

[0042] It should be noted that the excavation of the box foundation should be carried out away from the rainy season, and water interception and drainage facilities should be prepared around the site before excavation and clearing. In addition, the green belt within the filling range of EPS layer 4 is limited by the thickness of the soil layer, and the tree species should be adjusted accordingly in the greening design.

[0043] According to the description and drawings of the utility model, those skilled in the art can easily manufacture or use the utility model, which is a roadbed structure suitable for use above a subway tunnel in soft soil, and can produce the positive effects described in the utility model.

[0044] It should be noted that the terms "including" and "having" and any variations thereof in the specification and claims of the present utility model and the above-mentioned drawings are intended to cover non-exclusive inclusions. The terms "installed", "set", "provided with", "connected", "connected", and "socketed" should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral structure; it can be a mechanical connection, or an electrical connection; it can be directly connected, or indirectly connected through an intermediate medium, or it can be an internal connection between two mechanisms, elements or components. For those of ordinary skill in the art, the specific meanings of the above terms in the present utility model can be understood according to the specific circumstances.

[0045] In the description of the present invention, it should be understood that the terms "one end", "the other end", "outside", "inside", "horizontal", "end", "length", "outer end", "left", "right" and the like indicate positions or positional relationships based on the positions or positional relationships shown in the drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the mechanism or element referred to must have a specific position, be constructed and operated in a specific position, and therefore cannot be understood as a limitation on the present invention. The terms "first" and "second" are also used only for the simplicity of description, and do not indicate or imply relative importance.

[0046] Furthermore, in practicing the claims of the present invention, those skilled in the art may understand and affect variations to the disclosed embodiments by studying the drawings, disclosure, and appended claims. In addition, in the claims and the specification, words such as "comprises", "comprising", etc. do not exclude other elements or steps, and non-plural nouns do not exclude their plural forms.

[0047] The above is only a preferred embodiment of the present invention and is not intended to limit the scope of implementation of the present invention. That is, all equivalent changes and modifications made according to the present invention are covered by the scope of the claims of the present invention and will not be listed one by one here.

Claims

1. A roadbed structure suitable for use above a subway tunnel in soft soil, characterized in that: The invention comprises a box-type foundation (1) whose lower part is located below the ground line (10); a medium-coarse sand layer (2) is provided on the top of the box-type foundation (1); an EPS layer (4) is provided above the medium-coarse sand layer (2); a metal pin (3) is pre-buried in the upper part of the box-type foundation (1); the upper end of the metal pin (3) passes through the medium-coarse sand layer (2) and is inserted into the EPS layer (4); a retaining wall (9) is provided around the medium-coarse sand layer (2) and the EPS layer (4); a pavement structure (7) is laid on the top of the EPS layer (4); and the side of the pavement structure (7) is adjacently fixed to the retaining wall (9).

2. A roadbed structure suitable for use above a subway tunnel in soft soil as claimed in claim 1, characterized in that: A drainage pipe (8) is pre-buried in the lower part of the retaining wall (9), one end of the drainage pipe (8) is connected to the outside, and the other end of the drainage pipe (8) is connected to the medium-coarse sand layer (2).

3. The roadbed structure suitable for use above a subway tunnel in soft soil as claimed in claim 1, characterized in that: A reinforced concrete slab (6) is cast between the pavement structure (7) and the EPS layer (4).

4. The roadbed structure suitable for use above a subway tunnel in soft soil as claimed in claim 1, characterized in that: The EPS layer (4) is composed of a plurality of EPS blocks.

5. A roadbed structure suitable for use above a subway tunnel in soft soil as claimed in claim 4, characterized in that: The EPS blocks adjacent to each other are arranged in a staggered manner.

6. A roadbed structure suitable for use above a subway tunnel in soft soil as claimed in claim 4, characterized in that: A claw-shaped metal connecting piece (5) is fixed between two adjacent EPS blocks.

7. The roadbed structure suitable for use above a subway tunnel in soft soil as claimed in claim 3, characterized in that: A claw-shaped metal connecting piece (5) is fixed between the reinforced concrete slab (6) and the EPS layer (4) therebelow.

8. The roadbed structure suitable for use above a subway tunnel in soft soil as claimed in claim 1, characterized in that: The bottom surface of the box-type foundation (1) is a horizontal plane, the top surface of the box-type foundation (1) is consistent with the longitudinal and transverse slopes of the pavement structure (7), and the pavement structure (7) is symmetrical about the center line of the designed road and has a decreasing slope from the middle to both sides.

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