Deformation control structure for implementing foundation pit engineering through reverse construction method

Abstract

The utility model belongs to the field of underground space development, and relates to a deformation control structure for implementing foundation pit engineering through a reverse construction method. According to the technical scheme, an enclosure structure is arranged on the periphery of a foundation pit, and a basement beam plate structure and middle supporting piles are arranged in the foundation pit; a temporary structure edge beam is arranged on the cantilever edge of the basement beam-slab structure, and a temporary supporting edge column is arranged below the temporary structure edge beam; an outer wall hidden beam is arranged on the side wall of the enclosure structure, and a space is reserved between the outer wall hidden beam and the temporary structure edge beam; a plurality of servo jacks are arranged in the space at intervals, are clamped between the outer wall hidden beam and the temporary structure edge beam and are aligned with a main beam of a basement beam and slab structure; a secondary beam of the basement beam-slab structure extends out of a temporary structure edge beam to abut against an outer wall hidden beam; secondary beam side plates are laid on the secondary beams between the servo jacks, and the secondary beam side plates and the servo jacks are arranged in a spaced mode. The influence of the construction process on buildings and underground pipe networks around the foundation pit in the reverse construction method deep foundation pit engineering can be effectively reduced.

Description

Technical Field

[0001] The utility model belongs to the field of underground space development, and particularly relates to a deformation control structure in the case of complex surrounding environment of the foundation pit in the central urban area and high requirements for deformation control of the foundation pit retaining structure. Background Technique

[0002] With the rapid development of urban underground space, new problems and challenges have continuously emerged in the design and construction of foundation pit projects. The urban underground space has changed from traditional single functions such as commerce and parking to underground complexes with multiple functions, and the scale of foundation pit projects has continuously increased. In addition, foundation pit projects in the central urban area are often adjacent to protection objects such as subways, protected buildings, and underground pipe networks. The surrounding environmental conditions of the foundation pit are becoming increasingly complex and sensitive, and the requirements for deformation control during the implementation of the foundation pit are also getting higher and higher.

[0003] The top-down method is a commonly used support method in the field of foundation pit engineering. In this method, intermediate support piles or columns are cast or driven at relevant positions inside the building to serve as the support structure for bearing the self-weight of the upper structure and construction loads before the bottom plate is sealed during the construction period. The structural beam and slab of each basement layer are excavated downward for construction as the horizontal support of the retaining structure. The top-down method has the following outstanding advantages compared with the conventional bottom-up method for foundation pits: (1) Since the structural beam and slab of the ground floor are completed first, the construction of the upper structure can be carried out synchronously during the downward top-down excavation process, thus significantly shortening the construction period; (2) It avoids the waste phenomenon of using temporary supports, and the economic benefits of the project are remarkable, which is conducive to realizing the green and sustainable development of foundation pit projects; (3) The horizontal top-down structural beam and slab support has large stiffness and high safety.

[0004] Although the top-down method has the above advantages, in the case of very high requirements for surrounding environment protection, there are still certain deficiencies in the top-down method for controlling foundation pit deformation: (1) The construction speed of the underground top-down structural beam and slab is usually slow. In soft soil areas represented by Shanghai, soft clay has rheological properties. Before the construction of the top-down beam and slab is completed and an effective horizontal support is formed, the foundation pit deformation will continuously accumulate and increase over time; (2) In order to ensure the construction quality and dimensional accuracy of the top-down structural beam and slab during the top-down construction, it is usually necessary to adopt the method of erecting a scaffolding for construction. Therefore, a certain depth of over-excavation is required at each stage of the foundation pit excavation process, which is also not conducive to foundation pit deformation control.

[0005] At present, the research on foundation pit projects implemented by the top-down method, especially the technical means for controlling the deformation of the foundation pit retaining structure and reducing the impact of the foundation pit on the surrounding environment, is still not mature. Content of the Utility Model

[0006] To solve the above technical problems, the present utility model provides a deformation control structure for implementing foundation pit engineering by the top-down method, which is particularly applicable to the development of large-depth multi-layer underground spaces under complex and sensitive environmental conditions in the central urban area, and can effectively reduce the impact of the construction process on the surrounding buildings and underground pipe networks during the top-down deep foundation pit engineering.

[0007] The technical solution of the present utility model is as follows: A deformation control structure for implementing foundation pit engineering by the top-down method, with a retaining structure around the foundation pit and a basement beam-slab structure and intermediate supporting pile columns inside the foundation pit; the main beams of the basement beam-slab structure are fixed on the intermediate supporting pile columns, the secondary beams of the basement beam-slab structure are fixed on the main beams, the basement beam-slab structure extends out of the intermediate supporting pile columns, a temporary structural side beam is arranged on the extended side of the basement beam-slab structure, and a temporary supporting side column is arranged under the temporary structural side beam; an external wall concealed beam is arranged on the side wall of the retaining structure, the external wall concealed beam and the temporary structural side beam are at the same elevation, and there is a space between the external wall concealed beam and the temporary structural side beam; a plurality of servo jacks are arranged at intervals in the space, and a supporting plate is arranged under the servo jacks; one end of the supporting plate is fixed to the temporary structural side beam, and the other end is disconnected from the external wall concealed beam; the servo jacks are clamped between the external wall concealed beam and the temporary structural side beam and are aligned with the main beams; the secondary beams extend out of the temporary structural side beam and abut against the external wall concealed beam; a secondary beam side plate is laid on the secondary beams between the servo jacks, and the secondary beam side plate is arranged at intervals and separated from the servo jacks.

[0008] Based on the above technical features: The external wall concealed beam is connected to the retaining structure by suspension bars.

[0009] Based on the above technical features: The vertical main bars of the external wall and the water stop steel plates are reserved at the top and bottom of the external wall concealed beam.

[0010] Based on the above technical features: The first structural main bars and the second structural main bars are respectively reserved between the external wall concealed beam and the main beam.

[0011] Through the deformation control of the retaining structure for implementing the deep foundation pit engineering by the top-down method, the present utility model can effectively control the deformation of the retaining structure of the deep foundation pit engineering by the top-down method, and further reduce the impact of the foundation pit excavation construction on the surrounding buildings and underground pipe networks, which plays an important role in the urban renewal construction project. Description of the Drawings

[0012] Figure 1 is the sectional schematic diagram of the present utility model.

[0013] Figure 2 is the plan schematic diagram of the present utility model.

[0014] The reference numerals in the figure indicate: retaining structure 1; temporary supporting side column 2; intermediate supporting pile column 3; main beam 4; concealed beam in the exterior wall 5; servo jack 6; supporting plate 7; secondary beam side plate 8; vertical main reinforcement in the exterior wall 9; waterstop steel plate 10; secondary beam 11; temporary structural side beam 12; hanger bar 13; first structural main reinforcement 14; second structural main reinforcement 15. Detailed implementation manners

[0015] The following further elaborates on the detailed implementation manners of the present utility model in conjunction with the accompanying drawings. These implementation manners are only used to illustrate the present utility model and do not limit the present utility model.

[0016] In the description of the present utility model, it should be noted that the orientation or positional relationship indicated by the terms "center", "longitudinal", "transverse", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc. is based on the orientation or positional relationship shown in the accompanying drawings. It is only for the convenience of describing the present utility model and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be construed as a limitation of the present utility model.

[0017] In addition, in the description of the present utility model, unless otherwise specified, the meaning of "plural" is two or more.

[0018] As Figure 1 and Figure 2 shown, the perimeter of the foundation pit is the retaining structure 1, and the interior of the foundation pit is the basement beam-slab structure and the intermediate supporting pile column 3; the main beam 4 of the basement beam-slab structure is fixed on the intermediate supporting pile column 3, and the secondary beam 11 of the basement beam-slab structure is fixed on the main beam. In the top-down foundation pit engineering, the basement beam-slab structure also serves as the horizontal support of the retaining structure.

[0019] The basement beam-slab structure extends out of the intermediate supporting pile column 3. A temporary structural side beam 12 is provided at the cantilever side of the basement beam-slab structure, and a temporary supporting side column 2 is provided below the temporary structural side beam 12. After all the exterior walls of the basement structure are constructed, the temporary structural side beam 12 and the temporary supporting side column 2 can be chiseled off in sections. If the temporary structural side beam 12 does not affect the building function, it can be retained.

[0020] An exterior wall concealed beam 5 is provided on the side wall of the retaining structure 1, and the exterior wall concealed beam 5 is connected to the retaining structure 1 through suspension bars 13. The exterior wall concealed beam 5 and the temporary structure side beam 12 are at the same elevation, and there is a space between the exterior wall concealed beam 5 and the temporary structure side beam 12; a plurality of servo jacks 6 are arranged at intervals within this space, and a supporting plate 7 is provided under the servo jacks 6; one end of the supporting plate 7 is fixed to the temporary structure side beam 12, and the other end is disconnected from the exterior wall concealed beam 5. The servo jacks 6 are clamped between the exterior wall concealed beam 5 and the temporary structure side beam 12. Considering that the force of the servo jacks 6 is relatively large and it is easy to damage the structural floor slab, the servo jacks 6 can be aligned with the main beam 4.

[0021] The secondary beam 11 extends out of the temporary structure side beam 12 and abuts against the exterior wall concealed beam 5; a secondary beam side plate 8 is laid on the secondary beam between the servo jacks 6, and the secondary beam side plate 8 is arranged at intervals with the servo jacks 6. If there is a problem with the servo jacks 6, the secondary beam side plate and the secondary beam are equivalent to a pier, serving as a safety reserve and being able to support the retaining structure.

[0022] Vertical main bars 9 of the exterior wall and a water stop steel plate 10 are reserved at the top and bottom of the exterior wall concealed beam 5. The exterior wall concealed beam 5 will be used as part of the permanent exterior wall of the basement. Because the exterior wall is poured in multiple times, a water stop steel plate 10 needs to be set at the construction joint position to ensure no leakage during the normal use stage.

[0023] A first structural main bar 14 and a second structural main bar 15 are respectively reserved between the exterior wall concealed beam 5 and the main beam 4. When the servo jacks 6 act, the retaining structure 1 will be pushed outwards, and at this time, the first structural main bar 14 and the second structural main bar 15 are disconnected, which will not affect the operation of the servo jacks 6.

[0024] At the same time, in order to prevent the supporting plate 7 from being damaged when the servo jacks 6 work, one end of the supporting plate 7 is fixed to the temporary structure side beam 12, and the other end is disconnected from the exterior wall concealed beam 5.

[0025] The concept of the above technical solution is as follows: In the foundation pit project, due to the excavation and unloading of the soil in the foundation pit, the retaining structure 1 deforms towards the inside of the foundation pit, which in turn causes the settlement and deformation of the buildings and underground pipelines outside the pit. The magnitude of the deformation of the retaining structure 1 is directly related to the settlement and deformation of the surrounding buildings and underground pipelines. Therefore, controlling the deformation of the retaining structure is beneficial to reducing the impact of the foundation pit excavation on the surrounding environment. In this technical solution, the basement beam-slab structure is used as the large-rigidity top-down structure beam-slab, which horizontally resists the retaining structure 1, and the additional servo jacks 6 apply a horizontal thrust to the retaining structure 1, which can effectively reduce the deformation of the foundation pit retaining structure.

[0026] The above are only the preferred embodiments of the present invention. It should be noted that for those of ordinary skill in the art, without departing from the technical principle of the present invention, several improvements and substitutions can be made, and these improvements and substitutions should also be regarded as the protection scope of the present invention.

Claims

1. A deformation control structure for implementing foundation pit engineering by the top-down method. The periphery of the foundation pit is a retaining structure (1), and the interior of the foundation pit is a basement beam-slab structure and intermediate supporting pile columns (3); the main beams (4) of the basement beam-slab structure are fixed on the intermediate supporting pile columns (3), and the secondary beams of the basement beam-slab structure are fixed on the main beams (4), characterized in that: The basement beam-slab structure extends outwards from the middle supporting pile column (3), and a temporary structural side beam (12) is arranged at the extended edge of the basement beam-slab structure. A temporary supporting side column (2) is arranged below the temporary structural side beam (12); an external wall concealed beam (5) is arranged on the side wall of the enclosure structure (1), and the external wall concealed beam (5) is at the same elevation as the temporary structural side beam (12), and there is a space between the external wall concealed beam (5) and the temporary structural side beam (12); a plurality of servo jacks (6) are arranged at intervals within the space, and a supporting plate (7) is arranged below the servo jacks (6); one end of the supporting plate (7) is fixed to the temporary structural side beam (12), and the other end is disconnected from the external wall concealed beam (5); the servo jacks (6) are clamped between the external wall concealed beam (5) and the temporary structural side beam (12) and are aligned with the main beam (4); the secondary beam extends out of the temporary structural side beam (12) and abuts against the external wall concealed beam (5); a secondary beam side plate (8) is laid on the secondary beam between the servo jacks (6), and the secondary beam side plate (8) is arranged at intervals and separately from the servo jacks (6).

2. The deformation control structure for implementing foundation pit engineering by the top-down method according to claim 1, characterized in that: The external wall concealed beam (5) is connected to the enclosure structure (1) through suspension bars (13).

3. A deformation control structure for implementing foundation pit engineering by the top-down method according to claim 1, characterized in that: Vertical main bars (9) of the external wall and water stop steel plates (10) are reserved at the top and bottom of the external wall concealed beam (5).

4. A deformation control structure for implementing a foundation pit project by the top-down method according to claim 1, characterized in that: First structural main bars (14) and second structural main bars (15) are respectively reserved between the external wall concealed beam (5) and the main beam (4).

Images