Foundation pit support changing structure replacing concrete support changing plate

Abstract

The utility model belongs to the field of underground space development, and relates to a foundation pit support changing structure for replacing a concrete support changing plate, which adopts the technical scheme that in a foundation pit constructed by a sequential construction method, a building main body structure sequentially built in the foundation pit from bottom to top comprises a foundation bottom plate, a basement outer wall body, a basement inner wall body and a basement structure floor slab; bottom plate periphery support replacement is carried out between the foundation bottom plate and the foundation pit support structure, and a foundation pit fat groove is formed between the basement outer wall body and the foundation pit support structure; and the foundation pit fertilizer groove is filled with flow-state solidified soil. The structure is particularly suitable for development of high-underground-water-level large-depth multi-layer underground space, the structure is combined with the flow-state solidified soil technology, concrete replacement supporting plates on the periphery of the basement are replaced, and the purposes that the construction cost is saved, and meanwhile the waterproof effect of the basement in the normal use stage is enhanced can be achieved.

Description

Technical Field

[0001] The utility model belongs to the field of underground space development, in particular to a foundation pit replacement support structure for replacing a concrete replacement support plate in the development of underground space with a high groundwater level. Background Art

[0002] With the rapid development of urban underground space, foundation pit engineering, as one of the most common methods of underground space development, has been widely used. In construction pit projects with deep excavations and sequential construction, the most commonly used support system is a pile row + internal support system, which features a relatively mature construction process, taking into account requirements such as deformation control. Piles are used as the foundation pit retaining structure to withstand the unbalanced earth and water pressures inside and outside the pit. During the layered excavation of the foundation pit, the external water and soil pressure is transmitted to the pile rows and then to the internal supports. As underground structure construction progresses, the existing internal supports need to be removed layer by layer from the bottom up. To ensure the stability of the foundation pit project, a support replacement structure is required to safely and orderly transfer the water and soil pressure on the foundation pit retaining structure to the basement structure. This process is called "foundation pit support replacement." Conventional support replacement includes two types: bottom slab support replacement and mid-floor slab support replacement. Bottom slab support replacement refers to the full pouring of the bottom slab. The mid-slab refers to the floor slabs within the basement. The mid-slab slab supports are typically concrete slabs of a certain thickness, installed in the pit fertilizer trough between the foundation pit retaining structure and the basement mid-slab, to transmit force. Openings should be provided at intervals within the slabs to allow construction workers to remove the basement exterior wall formwork and perform waterproofing work. These openings also serve as passageways for future compaction backfill between the foundation pit retaining structure and the basement exterior wall.

[0003] Conventional foundation pit replacement structures usually have the following problems: (1) The project cost is high. In the foundation pit project implemented by the conventional sequential method, temporary replacement force transfer plates need to be set up around the elevation of each floor of the basement. In the permanent stage, the replacement force transfer plates will be left in the soil as waste, resulting in a waste of resources. (2) Due to the presence of replacement components, the basement external waterproofing will be interrupted at the replacement position, resulting in the inability to form a complete external waterproofing on the outside of the basement, which in turn leads to water leakage problems in the basement during the permanent use stage. (3) The replacement of the middle floor slab usually uses the interval opening as the backfill channel for the fertilizer trough of the foundation pit, but this method usually results in the fertilizer trough around the foundation pit not being backfilled densely, becoming a cavity where groundwater gathers, which is also prone to basement leakage. (4) The construction is complicated. In addition to increasing the construction process of the replacement structure, after the basement is completed, the construction personnel also need to enter and exit the interval opening position of the middle floor slab replacement to remove the basement exterior wall formwork and carry out waterproofing construction. The construction is difficult and affects the construction quality of the building's external waterproofing.

[0004] Fluidized soil solidification technology involves mixing a certain amount of chemical soil solidifier with the soil. This special solidifier undergoes a series of physical and chemical reactions with the soil, thereby increasing the structural strength of the soil and improving its engineering performance. This method offers advantages such as rapid consolidation, good impermeability, simple construction, and low construction noise. Currently, some foundation pit projects are beginning to use fluidized soil as a backfill material for fertilizer troughs. However, current foundation pit engineering applications generally only consider the advantages of fluidized soil in ensuring the quality of fertilizer trough backfill and its ease of construction, without fully exploring its material properties.

[0005] At present, the research on the implementation of foundation pit engineering by sequential construction method, especially the technical means to improve the current conventional foundation pit replacement support technology problems and enhance the waterproof effect of the basement in the permanent use stage, is still immature. Utility Model Content

[0006] The utility model provides a foundation pit replacement support structure that replaces concrete replacement support plates, which is particularly suitable for the development of multi-layer underground spaces with high groundwater levels and large depths. The structure combines fluidized soil solidification technology to replace the concrete replacement support plates around the basement, which can save engineering costs and at the same time enhance the waterproof effect of the basement during normal use.

[0007] A technical solution for a foundation pit replacement support structure that replaces concrete replacement support plates is as follows: in a foundation pit constructed by a sequential construction method, the main building structure constructed in the foundation pit from bottom to top includes a foundation slab, a basement outer wall, a basement inner wall and a basement structural floor slab; between the foundation slab and the foundation pit retaining structure is a slab perimeter replacement support, between the basement outer wall and the foundation pit retaining structure is a foundation pit fertilizer trough; the foundation pit fertilizer trough is filled with fluidized solidified soil.

[0008] Based on the above technical features: the base plate peripheral support is made of plain concrete or the fluidized solidified soil. When the base plate support is subjected to a small force, the fluidized solidified soil can also be used.

[0009] Based on the above technical features: continuous basement external waterproofing is arranged outside the basement outer wall.

[0010] The concept of the above technical solution is as follows: Conventional foundation pit projects require temporary concrete replacement plates to transfer the water and soil pressure on the foundation pit retaining structure to the basement structure. Due to the existence of temporary concrete replacement plates, the basement external waterproofing will be interrupted at the replacement position, resulting in the inability to form a complete external waterproofing on the outside of the basement. In addition, the concrete replacement plates of the middle floor slabs usually use the spaced openings as backfill channels for the fertilizer troughs of the foundation pit, but this method usually results in the fertilizer troughs around the foundation pit being unable to be backfilled densely, becoming cavities where groundwater gathers, and is also not conducive to the removal of the exterior wall formwork and the construction of waterproofing operations. The utility model fully utilizes the advantages of fluidized solidified soil such as high strength, fast consolidation speed, and good anti-seepage performance. With the removal of the foundation pit support and the backbuilding of the basement, the basement external waterproofing is constructed in a timely manner and the fluidized solidified soil is used to backfill the fertilizer trough. The strength of the fluidized solidified soil is relatively high, and can reach 2MPa in actual projects. In addition, the fluidized solidified soil has a fast consolidation speed, and the strength can reach 0.3-0.5MPa in 3 days, which can meet construction needs and does not affect the construction period. In addition, the fluidized solidified soil is close to liquid before solidification, which can fully ensure the backfill is dense. After solidification, it has good anti-seepage performance and can be used as a waterproof measure itself, further ensuring that there will be no leakage problems in the basement during the permanent use stage.

[0011] This new utility model uses liquid solidified soil to replace concrete support plates in foundation pit projects, effectively saving construction costs. Furthermore, the waterproofing membrane can be continuously passed through, and the fluid solidified soil itself is impermeable, effectively preventing basement leakage, playing an important role in underground space construction projects. BRIEF DESCRIPTION OF THE DRAWINGS

[0012] Figure 1 It is a structural diagram of the present utility model.

[0013] The numbers in the figure are as follows: foundation pit retaining structure 1; internal support 2; foundation bottom plate 3; bottom plate peripheral replacement support 4; basement structure floor slab 5; basement outer wall 6; basement outer waterproofing 7; fluidized solidified soil 8. DETAILED DESCRIPTION

[0014] The following is a further detailed description of the specific embodiments of the present invention in conjunction with the accompanying drawings. These embodiments are only used to illustrate the present invention, and are not intended to limit the present invention.

[0015] In the description of the present invention, it should be noted that the terms "center," "longitudinal," "lateral," "upper," "lower," "front," "back," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," and "outer," etc., indicating directions or positional relationships, are based on the directions or positional relationships shown in the accompanying drawings and are intended solely to facilitate the description of the present invention and simplify the description. They do not indicate or imply that the devices or components referred to must have a specific direction, be constructed, or operate in a specific direction. Therefore, they should not be construed as limitations on the present invention. Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0016] The utility model provides a foundation pit replacement support structure that replaces concrete replacement support plates. In the development of multi-layer underground spaces with high groundwater levels and great depths, the structure combines fluidized solidified soil technology to replace temporary concrete replacement support plates around the basement, thereby saving project costs and enhancing the waterproofing effect of the basement during normal use.

[0017] With reference to the accompanying drawings, the detailed description is as follows.

[0018] Figure 1 The figure shows the replacement support phase of the foundation pit during the sequential construction method. Within the foundation pit retaining structure 1, temporary internal supports 2 are removed layer by layer, and construction of the basement foundation slab 3, basement exterior wall 6, basement interior wall, and basement structural floor slab 5 proceeds layer by layer. A fertilizer trough is located between the basement exterior wall 6 and the foundation pit retaining structure 1. Replacement support 4 is performed around the foundation slab 3 and the foundation pit retaining structure 1.

[0019] In the prior art, concrete support plates are used in the foundation pit fertilizer trough, which are generally set between each basement structural floor and the foundation pit retaining structure 1. However, in the present invention, concrete support plates are not set in the foundation pit fertilizer trough, but fluidized solidified soil 8 is filled in the foundation pit fertilizer trough.

[0020] The base plate peripheral support 4 can be plain concrete or fluidized solidified soil 8.

[0021] A continuous basement external waterproofing 7 is provided outside the basement external wall 6 .

[0022] The construction steps of this structure are as follows: after the foundation slab 3 and the surrounding replacement bracing 4 have reached the designed strength, the lowest internal support is removed, and the basement structural floor slab 5, basement interior wall, and basement exterior wall 6 are constructed, followed by the basement exterior waterproofing 7. After the basement exterior waterproofing 7 is completed, the foundation pit fertilizer trough outside the basement is filled with fluidized solidified soil 8.

[0023] After the fluidized solidified soil 8 in the lower layer reaches the design strength, the internal support of the previous layer is removed, and the basement structure floor 5, basement inner wall, basement outer wall 6 and basement outer waterproofing 7 of the basement are constructed, and then the fluidized solidified soil 8 is filled in the foundation pit fertilizer trough outside the basement. The backfill height of each step is the height of one basement floor. Therefore, replacing the conventional concrete support plate around the foundation pit can also ensure the safety of the foundation pit.

[0024] In summary, the present invention gives full play to the advantages of high strength, fast consolidation speed and good anti-seepage performance of fluidized solidified soil, and uses fluidized solidified soil to replace the temporary replacement plate belts set around the basement at the location of each floor slab. This technical measure has the following outstanding advantages: (1) It saves a large number of temporary concrete replacement plates in conventional foundation pit projects, saving project costs; (2) It is convenient to construct, avoiding the conventional tedious construction of concrete replacement plates, and at the same time, the working environment during the construction of basement external waterproofing is significantly improved, making it easier to ensure the construction quality of building external waterproofing; (3) Conventional foundation pit basement external waterproofing needs to be disconnected at the location of concrete replacement plates, while the technical measures of the present invention can ensure the continuity of basement external waterproofing, and the waterproof membrane is not easily damaged; (4) Fluidized solidified soil can ensure dense filling and has good anti-seepage performance, so it is also conducive to ensuring the reliability of basement waterproofing during normal use.

[0025] The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and replacements can be made without departing from the technical principles of the present invention. These improvements and replacements should also be regarded as the scope of protection of the present invention.

Claims

1. A foundation pit replacement support structure that replaces concrete replacement support plates, characterized by: In a foundation pit constructed by a sequential construction method, the main building structure constructed in the foundation pit from bottom to top includes a foundation slab (3), a basement outer wall (6), a basement inner wall and a basement structural floor (5); between the foundation slab (3) and the foundation pit retaining structure (1) is a slab peripheral exchange support (4); between the basement outer wall (6) and the foundation pit retaining structure (1) is a foundation pit fertilizer trough; the foundation pit fertilizer trough is filled with fluidized solidified soil (8).

2. A foundation pit replacement support structure that replaces concrete replacement support plates according to claim 1, characterized in that: The bottom plate peripheral replacement support (4) is plain concrete or the fluidized solidified soil (8).

3. The foundation pit replacement support structure as claimed in claim 1, which replaces the concrete replacement support plate, is characterized by: A continuous basement external waterproofing (7) is provided outside the basement external wall (6).

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