Inverted well wall foundation pit support applied to pipeline engineering

Abstract

The utility model provides an upside-down hanging well wall foundation pit support applied to pipeline engineering, which comprises a constructional column, a horizontal steel grating and a horizontal inner support, the constructional column comprises a plurality of prefabricated constructional column units connected with the horizontal steel grating, the prefabricated constructional column units are box-shaped columns, and the horizontal inner support is connected with the horizontal steel grating. Four holes are respectively formed in two side column walls, in the same direction as the pipeline, of the box column; and the horizontal steel grating longitudinally penetrates through the holes and is connected with the constructional column unit. The upside-down hanging well wall foundation pit support is suitable for newly-built or rebuilt pipeline foundation pit support with complex underground existing pipelines; by additionally arranging the constructional columns, the risk of deformation and instability of a traditional linear upside-down hanging well wall supporting form due to the fact that the longitudinal size is too large is solved, and the application range of the upside-down hanging well wall supporting technology is wider.

Description

Technical Field

[0001] This utility model belongs to the field of foundation pit support structure in geotechnical engineering, and particularly relates to an inverted well wall foundation pit support technology for pipeline engineering that adds structural columns. Background Technology

[0002] With the continuous development and quality improvement of urbanization, the problems of insufficient capacity and safety hazards of existing underground municipal pipeline networks (such as water supply, drainage, and electricity) are becoming increasingly prominent, urgently requiring expansion and upgrading. However, due to the imperfect planning during the early design and construction of municipal pipelines and the narrowness of urban space, the construction difficulty of pipeline repair or new pipelines has increased. Many pipeline projects no longer have the conditions for slope excavation, and common pipeline foundation pit support methods such as sheet pile support and steel pipe pile support are often not suitable for areas with dense existing pipelines. In general, the reverse construction method, such as the inverted well wall support structure, is often used in such areas.

[0003] Inverted manhole wall support structures are mostly used for the excavation and support of manhole foundation pits, and are less commonly used for pipeline engineering foundation pits with linear distribution. This is because the stress mode of the inverted manhole wall is horizontal circumferential stress, which is not suitable for the support of linearly distributed foundation pits in principle. Therefore, it is necessary to improve the traditional inverted manhole wall support structure so that it can be reasonably applied to pipeline engineering foundation pit support and effectively protect existing pipelines. Utility Model Content

[0004] This invention provides an inverted well wall foundation pit support method for pipeline engineering foundation pit support.

[0005] A type of inverted well wall foundation pit support for pipeline engineering is characterized by comprising structural columns, horizontal steel grids, and horizontal internal supports. The structural columns encompass several prefabricated structural column units connected to the horizontal steel grids. Each prefabricated structural column unit is a box-shaped column. Four holes are opened on each of the two side walls of the box-shaped column in the same direction as the pipeline. The horizontal steel grids pass longitudinally through the holes and are connected to the structural column units.

[0006] Preferably, the length of each section of the box-shaped column is 500-600mm.

[0007] Preferably, the structural columns are symmetrically arranged on both sides of the foundation pit, with a spacing of 4-5m along the length of the pipeline.

[0008] Preferably, the plurality of structural column units are vertically fixed by connecting bolts using connecting angle steel.

[0009] Preferably, the horizontal steel grating is provided with vertical connecting bars on the inner and outer sides, and a steel mesh is provided, and then shotcrete is applied to form a shotcrete layer.

[0010] Preferably, the horizontal inner support is a steel support, which is welded to the structural column, with a horizontal spacing of 4-5m and a vertical spacing of 1.0-1.5m.

[0011] Preferably, corner supports are installed at the four inner corners of the inverted well wall foundation pit support to increase the support strength.

[0012] Preferably, the structural column is installed at the location where the horizontal inner support is provided.

[0013] The inverted well wall foundation pit support of this utility model has the following effects:

[0014] 1. Applicable to the foundation pit support of newly built or renovated pipelines with complex existing underground pipelines;

[0015] 2. By adding structural columns, the risk of deformation and instability of traditional linear inverted well wall support due to excessive longitudinal dimensions is solved, making the application range of inverted well wall support technology more extensive. Attached Figure Description

[0016] Figure 1 This is a plan view of a linear inverted well wall foundation pit support structure with added structural columns using this utility model.

[0017] Figure 2 This is a cross-sectional schematic diagram of a linear inverted well wall foundation pit support structure with added structural columns using this utility model.

[0018] Figure 3 This is a schematic elevation view of a linear inverted well wall foundation pit support structure with added structural columns, which utilizes this utility model.

[0019] Figure 4 This is a schematic diagram of the structural column unit component node of the linear inverted well wall foundation pit support structure with added structural columns using this utility model.

[0020] Numbering in the diagram: 1-Structural column, 2-Horizontal steel grating, 3-Splicing component, 4-New pipeline, 5-Horizontal internal support, 6-Corner support, 7-Shotcrete layer, 8-Foundation pit bottom sealing, 9-Concrete capping beam, 10-Connecting angle steel, 11-Connecting bolt, 12-Capping beam bottom embedded steel plate, 13-Pipe bottom sand base Detailed Implementation

[0021] Traditional inverted well wall support methods are mostly used for the foundation pit support of inspection wells. However, since the stress mode of the inverted well wall is horizontal circumferential stress, it is not suitable for the support of linearly distributed foundation pits in principle.

[0022] This invention improves upon the traditional inverted well wall support structure, making it more suitable for pipeline engineering foundation pit support.

[0023] like Figure 1-4The illustrated inverted well wall foundation pit support with added structural columns mainly consists of structural columns 1, horizontal steel grids 2, and horizontal internal supports 5. The structural columns 1 encompass several prefabricated structural column units connected to the horizontal steel grids 2. Each structural column unit is a box-shaped column with a length of approximately 500mm. Four holes are opened on each of the two side walls of the box-shaped column in the same direction as the pipeline. The horizontal steel grids 2 pass longitudinally through these holes and connect to the structural column units. Multiple structural column units are vertically fixed by connecting angle steel 10 and connecting bolts 11. The structural columns 1 are symmetrically arranged on both sides of the foundation pit, with a spacing of 4m along the length of the pipeline. Preferably, the structural columns 1 are installed at the locations where the horizontal internal supports 5 are provided, which can effectively transfer the horizontal earth pressure borne by the horizontal steel grids 2 (lacking internal support) to the connected structural columns 1.

[0024] The horizontal steel grating 2 undergoes processing steps such as connection with the structural column units in the factory, and is trial-assembled outside the well. As the earthwork is excavated, it is laid from top to bottom into the foundation pit, and the structural column units are also spliced ​​from top to bottom. Vertical connecting steel bars and steel mesh are installed on the inner and outer sides of the horizontal steel grating 2, followed by shotcrete to form a shotcrete layer 7. The horizontal inner support 5 is a steel support, welded to the structural column 1, with a horizontal spacing of 4m and a vertical spacing of 1.0-1.5m. This forms a load-bearing structure consisting of the horizontal steel grating 2, the horizontal inner support 5, and the vertical structural column 1. Corner supports 6 can be installed at the four inner corners of the inverted well wall foundation pit support to increase the support strength.

[0025] The inverted well wall foundation pit support is constructed according to the following procedures:

[0026] After the site is leveled, the existing buried objects are surveyed, and the location of existing pipelines is confirmed before construction is prepared.

[0027] The trench is excavated in layers, and concrete interlocking beams are constructed. The first horizontal internal support is erected. During the construction of the interlocking ring beam, longitudinal connecting steel bars are pre-embedded in the horizontal steel grid. The horizontal spacing of the connecting steel bars is 1.0 meter, and they are set in double rows in the grid.

[0028] Horizontal steel grating is processed outside the well. After the first steel grating is processed into a grating, it is trial-assembled on a flat ground. The error is controlled within a reasonable range. Only after it passes the inspection can it be mass-produced and used inside the well.

[0029] Excavate the earthwork, install the horizontal steel grid frame, excavate the first section 350mm for horizontal steel grid installation, over-excavate 150mm at the structural column position, set steel mesh inside and outside the horizontal steel grid, set double-layer vertical connecting bars along the horizontal steel grid, weld them to the pre-embedded bars of the lock ring beam, and spray concrete.

[0030] After the first section of the well wall reaches 70% strength, continue excavating the next section, with an excavation height of 500mm and an over-excavation of 150mm at the location of the structural column. Then, install the horizontal steel grating and splice the vertical structural column units for the next section.

[0031] Repeat the above construction steps until the next internal bracing is installed;

[0032] After excavating to 200mm below the second inner support, erect horizontal inner supports, and then each excavation depth shall not exceed 0.5m;

[0033] After the shotcrete and anchor support is completed, continue excavation in sections according to the above procedures until the foundation is reached;

[0034] A steel grating is laid on the base plate, and concrete is poured to form a closed structure.

[0035] For pipeline engineering foundation pits, when using inverted well wall support, a construction section is generally defined as no more than 14m long along the pipeline length, with an internal support installed approximately every 4m to reduce deformation of the horizontal steel grating 2 due to excessive length. However, the vertical spacing of the internal supports is generally more than 1m, and the horizontal steel grating 2 without internal support still suffers from excessive deformation or even instability. This utility model adds structural columns 1 composed of box-type columns, preferably at the location where the horizontal internal support 5 is installed. This transfers the horizontal earth pressure borne by the horizontal steel grating 2 lacking internal support to the connected structural column 1. The inverted well wall foundation pit support of a construction excavation section is disassembled into multiple inverted well wall support structure units of approximately 4m in length with sufficient strength and support, thus realizing the application of traditional inverted well wall support technology to the support of linearly distributed foundation pits.

[0036] The specific embodiments described above further illustrate the purpose, technical solution, and beneficial effects of this utility model. It should be understood that the above description is only a specific embodiment of this utility model and is not intended to limit the scope of protection of this utility model. Any modifications, equivalent substitutions, improvements, etc., made within the concept and principles of this utility model should be included within the scope of protection of this utility model.

Claims

1. A type of inverted well wall foundation pit support applied to pipeline engineering, characterized in that, It includes structural columns, horizontal steel grids, and horizontal internal supports. The structural columns encompass several prefabricated structural column units connected to the horizontal steel grids. Each prefabricated structural column unit is a box-shaped column. Four holes are opened on each of the two side walls of the box-shaped column in the same direction as the pipeline. The horizontal steel grids pass through the holes longitudinally and are connected to the structural column units.

2. The inverted well wall foundation pit support applied to pipeline engineering according to claim 1, characterized in that, Each section of the box-shaped column is 500-600mm long.

3. The inverted well wall foundation pit support applied to pipeline engineering according to claim 1, characterized in that, The structural columns are symmetrically arranged on both sides of the foundation pit, with a spacing of 4-5m along the length of the pipeline.

4. The inverted well wall foundation pit support applied to pipeline engineering according to claim 1, characterized in that, The multiple structural column units are vertically fixed by connecting bolts using connecting angle steel.

5. The inverted well wall foundation pit support applied to pipeline engineering according to claim 1, characterized in that, The horizontal steel grating is provided with vertical connecting bars on the inner and outer sides, and a steel mesh is provided. Shotcrete is then applied to form a shotcrete layer.

6. The inverted well wall foundation pit support applied to pipeline engineering according to claim 1, characterized in that, The horizontal internal supports are steel supports, welded to the structural columns, with a horizontal spacing of 4-5m and a vertical spacing of 1.0-1.5m.

7. The inverted well wall foundation pit support applied to pipeline engineering according to claim 1, characterized in that, Corner supports are installed at the four inner corners of the inverted well wall foundation pit support to increase the support strength.

8. The inverted well wall foundation pit support applied to pipeline engineering according to claim 1, characterized in that, The structural column is installed at the location where the horizontal internal support is set.

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