Construction method of foundation pit temporary stand column

Abstract

The construction method comprises the steps that according to the design form of a temporary steel pipe support and the position of the steel pipe stand column, pre-embedded angle steel is installed on an expanded foundation or a bearing platform, and the position of the pre-embedded angle steel corresponds to the outer side of the steel pipe stand column; the steel pipe stand columns and the embedded angle steel are temporarily welded and fixedly connected, so that the steel pipe stand columns are stably supported on the enlarged foundation or the bearing platform; after the temporary steel pipe support is installed into a whole and connected with the bridge stand column in an anchoring mode, temporary welding solidification between the steel pipe stand column and the embedded angle steel is relieved, and the steel pipe stand column is limited through the embedded angle steel; and foundation pit earthwork is backfilled and compacted, and the steel pipe stand columns are stably supported on the expanded foundation or the bearing platform under the limiting effect of the embedded angle steel. The method has the advantages that the temporary stand columns are more convenient to install and pull out, and the turnover efficiency is higher; the material is high in durability and corrosion resistance; horizontal displacement of the steel pipe support is prevented; the overall stability of the temporary steel pipe support is improved; construction is more flexible, and the installation adjustability of the temporary support is high.

Description

Technical Field

[0001] The invention relates to the technical field of bridge construction, and in particular to a construction method for temporary foundation pit columns. Background Art

[0002] At present, in order to solve the installation and stability problem of temporary steel pipe column foundation of cast-in-place bridge structure, there are mainly two ways: 1) The root of the steel pipe column is directly embedded in the expanded foundation or pedestal for integral casting; 2) Pre-embed steel pads on the expanded foundation or pedestal and then weld or bolt them to the steel pipe columns.

[0003] However, this approach has some limitations and obvious disadvantages: 1) The recyclability of temporary brackets is low: when the brackets are removed later, they need to be cut off in sections, which leads to a low turnover rate of the brackets and high consumables costs; 2. High precision requirement: If the steel pipe piles are accurately embedded in the cap, higher construction precision is required. Once the embedded position or angle deviates, it may have an adverse effect on the stability and safety of the entire structure. 3) Steel corrosion problem: Steel pipe piles are directly exposed to the air environment and are easily corroded by air, moisture and chemicals, which leads to steel corrosion, and may also corrode the structural steel bars, affecting the durability of the structure; 4) Long waiting time for foundation pit backfilling: Temporary columns can only be cut off from the root or the bolts can be unbolted after the construction of the bridge structure is completed, and finally the foundation pit of the pedestal can be backfilled, resulting in a long foundation pit cycle and high containment costs. The longer the foundation pit is open, the greater the safety risk. Summary of the invention

[0004] The purpose of the present invention is to provide a construction method for temporary columns of foundation pits in accordance with the deficiencies of the above-mentioned prior art, by pre-embedding galvanized anti-corrosion embedded angle steel inside the pedestal, and then temporarily welding and fixing the steel pipe columns and the embedded angle steel; when the entire steel pipe support is installed to form a whole and anchored to the bridge column, the temporary consolidation of the steel pipe column and the bottom angle steel is released, and finally the foundation pit is backfilled and compacted. This not only improves the overall stability of the steel pipe column support, but also creates construction conditions for backfilling the foundation pit in advance and directly removing the steel pipe columns at a later stage, and also ensures the anti-corrosion effect of the permanent structure.

[0005] The purpose of the present invention is achieved by the following technical solutions: A construction method for temporary columns in a foundation pit, characterized in that the construction method comprises the following steps: According to the design form of the temporary steel pipe support and the position of the steel pipe column, the embedded angle steel is installed on the expanded foundation or the cap, and the position of the embedded angle steel corresponds to the outer side of the steel pipe column; Temporarily welding and consolidating the steel pipe column and the embedded angle steel so that the steel pipe column is stably supported on the enlarged foundation or the cap; After the temporary steel pipe support is installed to form a whole and is anchored to the bridge column, the temporary welding consolidation between the steel pipe column and the embedded angle steel is released, and the embedded angle steel limits the steel pipe column; The foundation pit is backfilled and compacted, and the steel pipe column is firmly supported on the expanded foundation or the pedestal under the limiting effect of the embedded angle steel, and the bridge structure is constructed using the temporary steel pipe support.

[0006] Concrete is poured around the periphery of the embedded angle steel to wrap it and fill the gap between the embedded angle steel and the steel pipe column.

[0007] When the construction of the bridge structure above the ground is completed, that is, after the temporary steel pipe support is used up, the steel pipe column is directly pulled out by construction equipment.

[0008] The embedded angle steel is subjected to anti-corrosion galvanizing treatment.

[0009] The embedded angle steel is arranged around the column foot pad of the steel pipe column.

[0010] The advantages of the present invention are: 1) Temporary columns are easier to install and remove, and have higher turnover efficiency: The material has strong turnover and operability: the method of consolidating with embedded angle steel and temporary columns can be used to backfill the foundation pit in advance, saving the rental period of foundation pit enclosure and supporting materials; the method of removing the pipe piles is simple. After cutting off the connecting pipe, the whole pile can be directly removed from the soil, which can not only reduce the loss rate of steel pipe materials, but also save the cost of demolition construction measures.

[0011] 2) Material durability and corrosion resistance: Corrosion resistance of galvanized angle steel: The surface of galvanized angle steel is galvanized, which can effectively prevent corrosion and rust of steel and improve the durability of the material. This is especially important for structures used in humid and corrosive environments. In contrast, steel pipe piles are directly embedded in the cap, and their anti-corrosion treatment may be more complicated or difficult to completely cover all surfaces, thereby increasing the risk of corrosion.

[0012] 3) The embedded galvanized angle steel plays a limiting role on the steel pipe column to prevent the horizontal displacement of the steel pipe bracket: Although the embedded galvanized angle steel and the steel pipe column are released from the consolidation form after the overall installation of the bracket is completed, they still play a limiting role to prevent the horizontal displacement of the steel pipe column.

[0013] 4) Backfilling the foundation pit and compacting it in advance can further improve the overall stability of the temporary steel pipe support.

[0014] 5) The construction is more flexible and the temporary support installation is highly adjustable. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 It is a structural schematic diagram of the present invention; Figure 2 This is a plan view of the embedded galvanized angle steel in the present invention. DETAILED DESCRIPTION

[0016] The features of the present invention and other related features are further described in detail below through embodiments in conjunction with the accompanying drawings to facilitate understanding by those skilled in the art: like Figure 1-2 As shown, the numbers 1-5 in the figure respectively represent: steel pipe column 1, expanded foundation or pedestal 2, embedded angle steel 3, foundation pit backfill 4, column foot pad 5.

[0017] Example: Figure 1 and Figure 2 As shown, the construction method of temporary foundation pit columns in this embodiment is applied to the construction of temporary steel pipe supports in the foundation pit. The temporary steel pipe supports are used to construct bridge structures. The temporary steel pipe supports are supported on the expanded foundation or pedestal 2 through steel pipe columns 1.

[0018] Specifically, the construction method in this embodiment includes the following steps: 1) Select the embedded parts type and requirements: According to the design form of the temporary steel pipe on site and the position of the steel pipe column 1, the specific specifications and embedded depth of the embedded angle steel 3 are calculated, and the embedded angle steel 3 is subjected to anti-corrosion galvanizing treatment to ensure the anti-corrosion effect on the permanent structure.

[0019] 2) Installation of embedded angle steel 3: The embedded angle steel 3 is embedded in the expanded foundation or the cap 2, and has a certain embedding depth to ensure the structural strength and stability of the embedded angle steel 3. The embedded angle steel 3 is exposed 0.1m from the concrete surface of the expanded foundation or the cap 2. At the same time, the exposed embedded angle steel 3 is wrapped with concrete, and the gap between the embedded angle steel 3 and the steel pipe column 1 is filled with concrete to prevent the embedded angle steel 3 from corroding the concrete.

[0020] 3) Installation of steel pipe column 1: A column foot pad 5 is provided at the bottom of the steel pipe column 1. Figure 2As shown, embedded angle steels 3 are respectively arranged around the column base plate 5, and the four embedded angle steels 3 all play a limiting and restraining effect on the column base plate 5. At this time, each embedded angle steel 3 is temporarily welded and consolidated with the column base plate 5, so that the steel pipe column 1 can be stably supported on the expanded foundation or the pedestal 2 through the embedded angle steels 3.

[0021] 4) Installation of temporary steel pipe supports.

[0022] A temporary steel pipe support body is installed on the steel pipe column 1, for example, the parallel pipe and the diagonal rod are installed, and the temporary steel pipe main frame is anchored and welded to the bridge column.

[0023] 5) Release the temporary welding consolidation between the steel pipe column 1 and each embedded angle steel 3, and finally backfill the foundation pit and compact the backfill soil 4. At this time, the steel pipe column 1, on the one hand, is limited by the embedded angle steel 3 and the foundation pit backfill soil 4 to prevent the temporary steel pipe support from horizontal displacement. Even if the steel pipe column 1 is not directly consolidated with the expanded foundation or the pedestal 2, it can still ensure that the temporary steel pipe support is firmly supported on the expanded foundation or the pedestal 2. This not only improves the overall stability of the steel pipe column support, but also creates construction conditions for backfilling the foundation pit in advance and directly removing the steel pipe column at a later stage.

[0024] 6) After the construction of the bridge structure above the ground is completed, the main body of the temporary steel pipe support is dismantled, and finally the temporary steel pipe column 1 is directly removed using a crawler crane.

[0025] The method of welding and fixing the embedded angle steel 3 and the steel pipe column 1 in this embodiment is more flexible during the construction process. If the bracket needs to be adjusted or changed, it can be completed by re-welding or cutting, which is relatively easy to achieve. If the steel pipe pile is directly embedded, its position and angle are fixed after the concrete foundation is poured, and it cannot be adjusted later.

[0026] Although the above embodiments have described in detail the concepts and embodiments of the present invention with reference to the accompanying drawings, ordinary technicians in this field can recognize that various improvements and changes can still be made to the present invention without departing from the scope of the claims, so they are not described one by one here.

Claims

1. A construction method for temporary columns in a foundation pit, characterized in that: The construction method comprises the following steps: According to the design form of the temporary steel pipe support and the position of the steel pipe column, the embedded angle steel is installed on the expanded foundation or the cap, and the position of the embedded angle steel corresponds to the outer side of the steel pipe column; Temporarily welding and consolidating the steel pipe column and the embedded angle steel so that the steel pipe column is stably supported on the enlarged foundation or the cap; After the temporary steel pipe support is installed to form a whole and is anchored to the bridge column, the temporary welding consolidation between the steel pipe column and the embedded angle steel is released, and the embedded angle steel limits the steel pipe column; The foundation pit is backfilled and compacted, and the steel pipe column is firmly supported on the expanded foundation or the pedestal under the limiting effect of the embedded angle steel, and the bridge structure is constructed using the temporary steel pipe support.

2. The construction method of a temporary foundation pit column according to claim 1, characterized in that: Concrete is poured around the periphery of the embedded angle steel to wrap it and fill the gap between the embedded angle steel and the steel pipe column.

3. The construction method of a temporary foundation pit column according to claim 1, characterized in that: When the construction of the bridge structure above the ground is completed, that is, after the temporary steel pipe support is used up, the steel pipe column is directly pulled out by construction equipment.

4. The construction method of a temporary foundation pit column according to claim 1, characterized in that: The embedded angle steel is subjected to anti-corrosion galvanizing treatment.

5. The construction method of temporary columns for foundation pit according to claim 1, characterized in that: The embedded angle steel is arranged around the column foot pad of the steel pipe column.

Images