Large-span non-column station covering and excavating structure

Abstract

The utility model relates to the technical field of station construction structures, in particular to a large-span column-free station cover and excavation structure which comprises at least two knife-handle-shaped enclosure structures, a cover and excavation top plate and a supporting structure. The cover excavation top plate is arranged above the cover excavation area, the at least two enclosure structures are arranged on the outer side of the cover excavation area, and the two ends of the cover excavation top plate are arranged on the upper portions of the enclosure structures correspondingly; a supporting structure is further arranged at the position of the cover excavation top plate and arranged above the cover excavation top plate. According to the utility model, a shallow foundation pit required by a permanent cover plate shallow foundation pit commonly used in the prior art is canceled, the main body deep foundation pit enclosure structure is arranged to be in a knife handle shape, and the upper part of the enclosure structure is used as a supporting part of the supporting structure for excavation of the cover and excavation top plate shallow foundation pit; the problem that in the prior art, when a permanent cover plate is constructed in a station through an existing cover-excavation method, a row of short piles often need to be additionally arranged on the outer side of an enclosure structure to serve as a supporting and retaining structure to be used for excavation of a top plate shallow foundation pit is solved.

Description

Technical Field

[0001] The utility model relates to the technical field of station construction structures, in particular to a large-span column-free station cover-and-dig structure. Background Art

[0002] The design and construction methods of the cover-and-cut method for subway stations with columns are relatively mature, but there is no unified approach to the design and construction of cover-and-cut methods for large-span column-free stations.

[0003] The cover-and-cut method requires the construction of a permanent cover-and-cut top plate first, and then the construction of the bottom plate and the middle plate from bottom to top. Usually, the span of a large-span column-free top plate is 20 meters, and the thickness of the top plate is more than 1.5 meters. Especially for the end supports of the axilized top plate, the thickness is more than 2 meters. The top plate has a large self-weight, the plate is very thick, and the nodes are difficult to handle. In addition, when the side wall structure has not yet been cast, the walls on both sides are overlapped on the enclosure structure, that is, the hinged form is inconsistent with the rigid connection form of the side wall under permanent working conditions. The design needs to consider the combination of construction conditions and permanent working conditions at the same time. Therefore, the design and construction of large-span column-free cover-and-cut stations are relatively complicated.

[0004] In detail, the prior art has the following deficiencies:

[0005] 1. When constructing permanent cover plates for existing cover-and-excavation stations, it is often necessary to add another row of short piles on the outside of the retaining structure as a retaining structure for excavating the shallow foundation pit of the top plate. The short piles are temporary structures and will be abandoned later, resulting in a waste of resources;

[0006] 2. For the method of using a knife-handle-shaped underground continuous wall as a cover excavation top plate shallow foundation pit retaining structure, since the longitudinal steel bars on one side do not extend to the ground, there is a risk of eccentric load when hoisting the steel cage of the ground-connected wall;

[0007] 3. For large-span column-free excavation top slabs, the slab thickness at the support is relatively thick, and the covering soil is relatively thick. When the knife-handle-shaped underground continuous wall is used as the top slab support, the local pressure on the underground continuous wall concrete is too large;

[0008] 4. The construction quality of the side wall slope construction joint reserved at the bottom of the cover plate support is poor, and there is a great risk of water leakage;

[0009] 5. Since the span of the column-free cover slab is 20 meters, and it is necessary to consider the covering soil and vehicle load during the construction period, the thickness is more than 1.5 meters, the concrete volume is large, and the quality is more difficult.

[0010] Based on the above shortcomings, there is an urgent need for a cover-excavation structure that can simultaneously solve the above shortcomings in the prior art. Utility Model Content

[0011] The invention purpose of the utility model is to solve the problems existing in the prior art and provide a large-span column-free station cover-excavation structure.

[0012] In order to solve the problems existing in the prior art, the utility model adopts the following technical solutions:

[0013] A large-span column-free station cover-and-excavation structure comprises at least two knife-handle-shaped enclosure structures, a cover-and-excavation top plate and a supporting structure;

[0014] The cover excavation top plate is arranged above the cover excavation area, at least two enclosure structures are arranged outside the cover excavation area, and two ends of the cover excavation top plate are respectively arranged on the upper part of the enclosure structure;

[0015] The support structure is also provided at the cover and top plate, and the support structure is provided above the cover and top plate.

[0016] As an improvement to the technical solution of the large-span column-free station cover-and-excavation structure of the utility model, a transversely arranged reinforcing support member is further arranged between every two of the enclosure structures.

[0017] As an improvement of the technical solution of the large-span column-free station cover-and-excavation structure of the utility model, the knife-handle-shaped enclosure structure includes a back-soil side and a front-soil side;

[0018] The height of the soil facing side is higher than that of the soil facing side, and both ends of the cover top plate are respectively arranged at the soil facing side.

[0019] As an improvement to the technical solution of the large-span column-free station cover-excavation structure of the utility model, a cover plate support is arranged on the back soil side, and the side wall construction joint reserved at the bottom of the cover plate support is a stepped construction joint.

[0020] As an improvement to the technical solution of the large-span column-free station cover-and-excavation structure of the utility model, a pre-embedded support member is arranged at the back-soil side.

[0021] As an improvement of the technical solution of the large-span column-free station cover-excavation structure of the utility model, the embedded support member is an embedded steel plate or a crown beam.

[0022] As an improvement on the technical solution of the large-span column-free station cover and excavation structure of the utility model, the retaining structure includes a plurality of steel cages, each of which includes a plurality of longitudinal steel bars and transverse steel bars; the longitudinal steel bars on the back-to-soil side and the longitudinal steel bars on the front-to-soil side both extend to the ground, and the longitudinal steel bars on the back-to-soil side are the same length as the longitudinal steel bars on the front-to-soil side.

[0023] As an improvement on the technical solution of the large-span column-free station cover-and-cut structure of the utility model, a plurality of temporary supporting components are arranged in the cover-and-cut area, and the plurality of temporary supporting components extend from the bottom to the cover-and-cut top plate and abut against the cover-and-cut top plate.

[0024] As an improvement of the technical solution of the large-span column-free station cover-excavation structure of the utility model, the temporary supporting components are temporary columns, steel lattice columns or steel pipe piles.

[0025] As an improvement of the technical solution of the large-span column-free station cover-excavation structure of the utility model, the supporting structure is a crown beam.

[0026] Beneficial effects of the utility model:

[0027] 1. Cancel the shallow foundation pit required for the permanent cover plate shallow foundation pit, make the main deep foundation pit retaining structure into a knife handle type, and use the upper part as the supporting structure for the top plate shallow foundation pit excavation, avoiding the waste of short piles of the cover plate shallow foundation pit.

[0028] 2. The longitudinal reinforcement on the back soil side and the front soil side of the ground-anchored wall are extended to the ground at the same time to avoid eccentric loading of the steel cage during lifting. When excavating the shallow foundation pit of the cover slab, the concrete on the back soil side and the longitudinal reinforcement are chiseled to the bottom of the cover slab, which can be used as structural reinforcement for lifting the steel cage, avoiding the risk of eccentric loading caused by different lengths of the steel cage.

[0029] 3. For large-span column-free capped excavation top slabs, the slab thickness at the supports is relatively thick. In order to avoid concrete damage caused by excessive pressure on the ground-connected wall, steel plates are embedded in the ground-connected wall at the cap slab supports. The embedded steel plates in the ground-connected wall at the cap slab supports relieve excessive local stress in the ground-connected wall and ensure the safety of foundation pit excavation.

[0030] 4. The side wall slope construction joint reserved at the bottom of the cover plate support is adjusted to a step shape to increase the bite connection between the cast-in-place concrete and the post-cast concrete, reduce the slip risk of the oblique cracks, increase the seepage path, and thus reduce the risk of seepage.

[0031] 5. Add two rows of temporary columns below the column-free cover slab to reduce the thickness of the top slab concrete. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] Figure 1 It is a schematic diagram of the structure of the utility model;

[0033] Figure 2 It is a schematic diagram of the local structure of the utility model before excavation;

[0034] Figure 3 It is a schematic diagram of the local structure of the utility model during excavation;

[0035] Figure 4 It is a structural schematic diagram of the embedded support member at the top plate of the cover plate in the utility model.

[0036] Explanation of the reference numerals: 1-enclosing structure; 2-top plate; 3-supporting structure; 4-temporary supporting components; 5-reinforced supporting members; 6-soil-repelling side; 7-soil-facing side; 8-cover plate support; 9-stepped construction joint; 10-embedded supporting members; 11-longitudinal reinforcement; 12-transverse reinforcement; 13-concrete pouring duct. DETAILED DESCRIPTION

[0037] In order to make the invention purpose, technical scheme and beneficial effects of the utility model clearer, the technical scheme in the embodiment of the utility model will be clearly and completely described below in conjunction with the drawings in the embodiment of the utility model. Obviously, the described embodiment is only a part of the embodiment of the utility model, rather than all the embodiments.

[0038] like Figures 1 to 4 As shown, a large-span column-free station cover-excavation structure is characterized in that it includes at least two knife-handle-shaped retaining structures 1, a cover-excavation top plate 2 and a supporting structure 3; the cover-excavation top plate 2 is arranged above the cover-excavation area, at least two retaining structures 1 are arranged outside the cover-excavation area, and the two ends of the cover-excavation top plate 2 are respectively arranged on the upper part of the retaining structure 1; a supporting structure 3 is also arranged at the cover-excavation top plate 2, and the supporting structure 3 is arranged above the cover-excavation top plate 2.

[0039] In the utility model, the shallow foundation pit required for the permanent cover shallow foundation pit commonly used in the prior art is eliminated, the main deep foundation pit enclosure structure 1 is set in a knife handle shape, and the upper part of the enclosure structure 1 is used as a supporting part of the supporting structure 3 for the shallow foundation pit excavation of the cover excavation top plate 2, which solves the problem that when the existing cover excavation method station is constructed with a permanent cover, a row of short piles are often added outside the enclosure structure 1 as a retaining structure for the excavation of the shallow foundation pit of the top plate. The short piles are temporary structures and are abandoned later, resulting in a waste of resources.

[0040] It should be noted that the present invention can be applied to ground-connected walls or bored piles. In the present invention, ground-connected walls are used as an example for explanation.

[0041] In some embodiments of the utility model, a transversely arranged reinforcing support member 5 is also arranged between each two enclosure structures 1, and the reinforcing support member 5 is transversely arranged in the middle or lower part of the enclosure structure 1, so as to strengthen the strength of the enclosure structure 1 through the reinforcing support member 5, and avoid the enclosure structure 1 from being overstressed and collapsing. As an example of this embodiment, the reinforcing support member 5 is a steel support, and the steel reinforcing support member 5 can ensure its strength, and the strength of the enclosure structure 1 can be better strengthened through the reinforcing support member 5.

[0042] In some embodiments of the present invention, the knife-handle-shaped enclosure structure 1 includes a back-to-soil side 6 and a front-to-soil side 7; the height of the front-to-soil side 7 is higher than that of the back-to-soil side 6, and both ends of the cover plate 2 are respectively arranged at the back-to-soil side 6.

[0043] Further, a pre-embedded support member 10 is provided at the back soil side 6. Further, the pre-embedded support member 10 is a pre-embedded steel plate or a crown beam.

[0044] In detail, since the enclosure structure 1 is in the shape of a knife handle, it includes two parts, a "knife handle" and a "knife body", the outer side of the "knife handle" is the soil facing side 7, and the outer side of the "knife body" is the soil backing side 6. The height of the "knife handle" is higher than the height of the "knife body", and there is a platform-shaped extension at the connection between the "knife body" and the "knife handle", and a pre-embedded support member 10 is arranged at the extension. The arrangement of the pre-embedded support member 10 alleviates the excessive local stress of the ground-connected wall, ensuring the safety of foundation pit excavation.

[0045] When the embedded support 10 is arranged, the pouring of the ground-connected wall concrete should not be affected, and the longitudinal reinforcement 11 on the back soil side 6 and the ground-connected wall concrete pouring conduit 13 should be avoided.

[0046] In addition, half of the thickness of the ground-connected wall is used as the cover plate support 8, so the thickness of the steel plate is generally less than half of the thickness of the ground-connected wall. As a specific example of this embodiment, the thickness of the ground-connected wall is 800mm, and the width of the embedded steel plate is generally not less than 300mm.

[0047] In some embodiments of the utility model, a cover plate support 8 is provided on the soil-retaining side 6 , and a side wall construction joint reserved at the bottom of the cover plate support 8 is a stepped construction joint 9 .

[0048] In detail, the side wall slope construction joint reserved at the bottom of the cover plate support 8 is adjusted to a step shape, which increases the bite connection between the cast-in-place concrete and the post-cast concrete, reduces the slip risk of the oblique cracks, increases the seepage path, and thus reduces the risk of seepage. This solves the problem in the prior art that the side wall slope construction joint reserved at the bottom of the cover plate support 8 has poor construction quality and a greater risk of water leakage.

[0049] In some embodiments of the present invention, the supporting structure 3 is a crown beam, wherein the crown beam can also serve as a top beam.

[0050] In some embodiments of the utility model, the retaining structure 1 includes a plurality of steel cages, each of which includes a plurality of longitudinal steel bars 11 and transverse steel bars 12; the longitudinal steel bars 11 on the back-to-soil side 6 and the longitudinal steel bars 11 on the front-to-soil side 7 both extend to the ground, and the longitudinal steel bars 11 on the back-to-soil side 6 are the same length as the longitudinal steel bars 11 on the front-to-soil side 7.

[0051] In detail, in order to avoid the risk of overloading during the installation of the knife-handle-shaped steel cage, part of the longitudinal steel bars 11 on the back soil side 6, which also serve as lifting steel bars, are extended to the ground, and are the same length as the longitudinal steel bars 11 on the front soil side 7. That is, the longitudinal steel bars 11 on the back soil side 6 of the ground-connected wall and the steel bars on the front soil side 7 are extended to the ground at the same time to avoid overloading during the installation of the steel cage. When excavating the shallow foundation pit of the cover plate, the back soil side concrete and the longitudinal steel bars 11 are chiseled to the bottom of the cover plate. In this way, the problem existing in the prior art of using a knife-handle-shaped underground continuous wall as a shallow foundation pit retaining structure 1 for the cover excavation top plate 2 is solved, because one side of the longitudinal steel bars 11 are not extended to the ground, and there is a risk of overloading during the installation of the ground-connected wall steel cage.

[0052] In some embodiments of the present invention, a plurality of temporary support members 4 are provided in the cover excavation area, and the plurality of temporary support members 4 extend from the bottom to the cover excavation top plate 2 and abut against the cover excavation top plate 2. The temporary support members 4 may be temporary columns, steel lattice columns or steel pipe piles.

[0053] In detail, by setting up the temporary support component 4, the thickness of the concrete of the cover excavation top plate 2 is reduced, that is, the effect of saving materials and costs is achieved. After the cover excavation is completed, the temporary support component 4 can be removed, which solves the problem in the prior art that for a large-span column-free cover excavation top plate 2, the plate thickness at the support is relatively thick, and the covering soil is relatively thick. When the knife-handle-shaped underground continuous wall is used as the top plate support, the local pressure of the underground continuous wall concrete is too large, and because the existing column-free cover plate has a span of 20 meters, it is necessary to consider the covering soil and vehicle load during the construction period during construction, and the thickness is more than 1.5 meters, the concrete volume is large, and the quality is relatively difficult.

[0054] The construction of the utility model includes the following steps:

[0055] S1. Set up enclosure structure 1

[0056] In order to avoid the risk of overloading during the lifting of the knife-shaped enclosure structure 1, the longitudinal steel bars 11 on the back side 6 of the enclosure structure 1, which also serve as lifting steel bars, are partially extended to the ground, with the same length as the longitudinal steel bars 11 on the front side 7. At the same time, the steel cage is pre-embedded with support members 10 at the position of the large-span column-free cover plate support 8. The pre-embedded support members 10 should not affect the pouring of the ground-connected wall concrete, avoid the pouring conduit, and should also avoid the longitudinal steel bars 11 on the back side 6. At the same time, half of the thickness of the ground-connected wall is used as the cover plate support 8, so the thickness of the steel plate is generally less than that of the ground-connected wall.

[0057] S2. Setting temporary support components 4

[0058] It mainly involves the construction of temporary vertical column pile foundations and lattice columns. After the site is leveled, temporary column pile driving and lattice column construction can be carried out. Among them, the top elevation of the lattice column should be set at the bottom of the excavation top plate 2.

[0059] S3. Large-span column-free cover slab shallow foundation pit excavation

[0060] After the ground-connected wall is poured and reaches the designed strength, the crown beam reinforcement is tied and concrete is poured. After the crown beam reaches the designed strength, the reinforcement support 5 is erected to support and a shallow foundation pit is excavated. For the knife-handle-shaped enclosure structure 1, as the foundation pit is excavated, half of the thickness of the ground-connected wall is chiseled off until the bottom of the cover plate support 8.

[0061] S4, large span column-free cover plate and side wall swing construction below cover plate support 8

[0062] The top of the side wall is generally not less than 500mm from the bottom of the axilla, and the step thickness of the construction joint at the bottom of the side wall is 200mm-350mm. Water-expandable waterstop strips and grouting pipes are placed on the steps. The vertical steel bars of the side wall are all constructed with Class I steel bar connectors. At the same time, a connecting hidden beam is set in the cover plate to relieve the stress concentration of the temporary column nodes.

[0063] S5. When the strength of the cover plate reaches 80% of the design value, the soil below the cover plate can be excavated, and the bottom plate and the side walls of the second negative floor, the middle plate and the side walls of the first negative floor can be cast in one go according to the conventional foundation pit.

[0064] Based on the embodiments of the utility model, all other embodiments obtained by ordinary technicians in this field without making any creative work shall fall within the scope of protection of the utility model.

Claims

1. A large-span column-free station cover-excavation structure, characterized in that: It comprises at least two knife-handle-shaped enclosure structures, a cover excavation top plate and a supporting structure; The cover excavation top plate is arranged above the cover excavation area, at least two enclosure structures are arranged outside the cover excavation area, and two ends of the cover excavation top plate are respectively arranged on the upper part of the enclosure structure; The support structure is also provided at the cover and top plate, and the support structure is provided above the cover and top plate.

2. The large-span column-free station cover-excavation structure according to claim 1 is characterized in that: A transversely arranged reinforcing support member is also arranged between every two of the enclosure structures.

3. The large-span column-free station cover-excavation structure according to claim 1 is characterized in that: The knife-handle-shaped enclosure structure includes a soil-facing side and a soil-receiving side; The height of the soil facing side is higher than that of the soil facing side, and both ends of the cover top plate are respectively arranged at the soil facing side.

4. The large-span column-free station cover-excavation structure according to claim 3 is characterized in that: A cover plate support is arranged on the soil-retaining side, and a side wall construction joint reserved at the bottom of the cover plate support is a stepped construction joint.

5. The large-span column-free station cover-excavation structure according to claim 3 is characterized in that: The back-to-soil side is provided with embedded support members.

6. The large-span column-free station cover-and-excavation structure according to claim 5 is characterized in that: The embedded support member is an embedded steel plate or a crown beam.

7. The large-span column-free station cover-and-excavation structure according to claim 3 is characterized in that: The enclosure structure includes a plurality of steel cages, each of which includes a plurality of longitudinal steel bars and transverse steel bars; the longitudinal steel bars on the soil-facing side and the longitudinal steel bars on the soil-facing side both extend to the ground, and the longitudinal steel bars on the soil-facing side and the soil-facing side have the same length.

8. The large-span column-free station cover-and-excavation structure according to claim 1 is characterized in that: A plurality of temporary supporting members are arranged in the cover-dig area, and the plurality of temporary supporting members extend from the bottom to the cover-dig top plate and abut against the cover-dig top plate.

9. The large-span column-free station cover-and-excavation structure according to claim 8 is characterized in that: The temporary supporting components are temporary columns, steel lattice columns or steel pipe piles.

10. The large-span column-free station cover-and-excavation structure according to claim 1 is characterized in that: The supporting structure is a crown beam.

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