Construction method and structure for supporting structure for pipeline group across foundation pit

Abstract

The application discloses a construction method of a support structure suitable for crossing pipeline groups in a foundation pit. The method comprises the following steps: constructing a surrounding structure around the foundation pit; constructing two first reinforced concrete supports and temporary columns near the pipeline groups to be relocated; excavating the soil and rock in the foundation pit near the pipeline groups to be relocated by slope excavation; when the excavation reaches 0.5m below the bottom elevation of the pipeline groups, the bottom is cleaned manually, and the bottom is leveled by using plain concrete; the residual soil around the temporary columns is cleaned; a steel mesh is laid on the plain concrete cushion, concrete is poured, and curing is performed until the design strength; the pipeline groups are relocated on the reinforced concrete structure plate; the foundation pit is excavated; the underground structure is constructed; and the foundation pit around the pipeline groups is backfilled. The method has the advantages of simple operation and stable structure. The application further discloses a support structure suitable for crossing pipeline groups in a foundation pit and constructed by using the construction method.

Description

Technical Field

[0001] This invention relates to the field of foundation pit engineering, and more specifically, to a construction method for a support structure applicable to a pipeline group spanning a foundation pit. The invention also relates to a support structure applicable to a pipeline group spanning a foundation pit, constructed using the aforementioned construction method. Background Technology

[0002] In order to minimize the interference with the surrounding environment and underground pipelines during the construction of foundation pit projects, vertical excavation is generally adopted for foundation pit construction.

[0003] When there are many underground pipelines around the foundation pit, the foundation pit construction will inevitably affect the existing underground pipelines. When the underground pipelines enter the excavation area of ​​the foundation pit, the pipelines are usually temporarily relocated to the outside of the foundation pit. After the foundation pit project is completed, the pipelines will be restored to their original locations.

[0004] Existing pipeline relocation technologies may have several adverse effects, such as high costs for multiple pipeline relocations, significant impact on the lives of surrounding residents, or the need to reduce the excavation pit area when there is no available space outside the pit for temporary pipeline relocation, in order to arrange underground pipelines outside the pit, which will affect the layout of underground engineering projects.

[0005] Existing patent document CN208949892U discloses a retaining structure that can span a foundation pit, which utilizes the rigidity of the pipeline itself to span the foundation pit, allowing for foundation pit excavation without relocating the pipeline; patent document CN105972313A discloses a pipeline suspension method and suspension structure that spans a foundation pit, which utilizes the foundation pit's own first concrete support, and sets a connecting beam and U-shaped steel frame between the two supports, thereby enabling the pipeline to span the foundation pit; patent document CN109914480A discloses setting a suspension or bracket in situ on the retaining piles, thereby enabling the pipeline to span the foundation pit.

[0006] None of the above methods have solved the problem of pipeline groups crossing the foundation pit. For example, various underground pipelines have different structural materials, material stiffness, and deformation control standards. When there are multiple underground pipelines within the foundation pit area, an economical and safe relocation method is needed to ensure the safety of the foundation pit project and surrounding pipelines. Summary of the Invention

[0007] The primary objective of this invention is to provide a construction method for a support structure applicable to pipeline groups spanning foundation pits, which is simple to operate and structurally stable.

[0008] The second objective of this invention is to provide a support structure applicable to a pipeline group spanning a foundation pit, constructed using the aforementioned construction method, which avoids secondary relocation of underground pipelines and reduces the impact of underground pipelines on the foundation pit plan.

[0009] To achieve the first objective of this invention, the technical solution is as follows: the construction method for the support structure applicable to pipeline groups spanning foundation pits, characterized by comprising the following steps,

[0010] Step 1: First, construct the retaining structure around the foundation pit;

[0011] Step 2: Construct the first layer of reinforced concrete supports and temporary columns near the underground pipeline group to be relocated.

[0012] Step 3: Excavate the earth and rock near the underground pipeline group to be relocated within the foundation pit, slope the excavation.

[0013] Step 4: When excavation reaches 0.5m below the bottom elevation of the underground pipeline group, manually clean the foundation and level it with plain concrete;

[0014] Step 5: Clear the debris around the temporary columns to ensure that the reinforcing steel bars can pass smoothly through the lattice columns later;

[0015] Step 6: Lay steel mesh on the plain concrete foundation, pour concrete and cure to the design strength;

[0016] Step 7: Relocate the underground pipeline network to the reinforced concrete structural slab;

[0017] Step 8: Excavate the foundation pit and erect supports in sequence;

[0018] Step 9: Underground structure construction, pouring the bottom slab, side walls, and top slab of the underground structure in sequence from bottom to top;

[0019] Step 10: Backfill the foundation pit around the underground pipeline group. Cement mortar is used for backfilling under the reinforced concrete structural slab.

[0020] In the above technical solution, the steel lattice material is Q235A steel.

[0021] In the above technical solution, in step ten, the backfilling measures under the reinforced concrete structural slab 2 are as follows.

[0022] When the space between the reinforced concrete slab and the underground structure is narrow, holes of 200mm to 300mm are pre-reserved in the reinforced concrete slab. After the underground structure is completed, cement mortar is poured through the pre-reserved holes.

[0023] When there is ample space between the reinforced concrete slab and the underground structure, earthwork is used for backfilling first, followed by filling the pre-reserved holes with cement mortar.

[0024] To achieve the second objective of the present invention, the technical solution of the present invention is as follows: a support structure applicable to a pipeline group spanning a foundation pit, constructed using the construction method described above, includes a reinforced concrete support, characterized in that it further includes a reinforced concrete structural slab and temporary columns.

[0025] The reinforced concrete support is located inside the foundation pit;

[0026] The reinforced concrete structural slab is erected in the foundation pit by means of the temporary columns;

[0027] The underground pipeline network is fixed to the reinforced concrete structural slab.

[0028] The reinforced concrete support includes a first reinforced concrete support and a second reinforced concrete support.

[0029] There are multiple first-level reinforced concrete supports, and these multiple first-level reinforced concrete supports are arranged in parallel in the support plane direction.

[0030] The reinforced concrete structural slab is fully laid between the two reinforced concrete supports in the planar direction and is arranged below the underground pipeline group in the elevation direction; both ends of the reinforced concrete structural slab pass through the temporary columns;

[0031] The temporary columns are arranged along the axis of the reinforced concrete support.

[0032] In the above technical solution, the reinforced concrete structural slab is arranged 0.5m below the underground pipeline group in the elevation direction.

[0033] In the above technical solution, the temporary column includes a steel lattice structure located at the upper part of the foundation pit and a bored pile located at the lower part of the foundation pit;

[0034] The steel lattice structure is welded from 4×160 angle steel;

[0035] The bored pile is equipped with a steel cage.

[0036] In the above technical solution, there are multiple steel lattice structures; the multiple steel lattice structures are arranged at intervals along the axis of the reinforced concrete support;

[0037] There are multiple bored piles; the multiple bored piles are arranged along the axis of the reinforced concrete support;

[0038] The reinforcing cage is welded to the steel lattice structure.

[0039] In the above technical solution, both ends of the reinforced concrete structural slab pass through the lattice column; the gusset plates of the lattice column are staggered vertically from the reinforcing bars of the reinforced concrete structural slab.

[0040] In the above technical solution, the underground pipeline group includes, but is not limited to, water supply and drainage pipes, power and telecommunications pipes, and natural gas pipes.

[0041] The present invention has the following advantages:

[0042] (1) This invention is applicable to foundation pit construction under various conditions where underground pipelines intrude into the excavation area of ​​the foundation pit;

[0043] (2) The present invention adds reinforced concrete structural slabs and temporary columns to the existing support system. During the construction of the foundation pit, various underground pipelines are first permanently relocated to the reinforced concrete structural slabs, and then the foundation pit is constructed on a large scale. Finally, after the underground structure is completed, it is backfilled in sequence, thereby avoiding secondary relocation of underground pipelines and reducing the impact of underground pipelines on the foundation pit plan. Attached Figure Description

[0044] Figure 1 This is a plan view of the present invention.

[0045] Figure 2 for Figure 1 A sectional view along the AA direction.

[0046] Figure 3 for Figure 1 BB-direction sectional view.

[0047] Figure 4 This is a schematic diagram of the connection structure between the water supply and drainage pipe and the concrete arc-shaped base.

[0048] In the diagram, 1-reinforced concrete support, 1.1-first reinforced concrete support, 1.2-second reinforced concrete support, 2-reinforced concrete structural slab, 3-steel lattice, 4-drilled pile, 4.1-reinforcing cage, 5-water supply and drainage pipe, 6-power and telecommunications pipe, 7-natural gas pipe, 8-concrete arc-shaped base, 9-temporary column, 10-underground pipeline group, 11-foundation pit. Detailed Implementation

[0049] The embodiments of the present invention will be described in detail below with reference to the accompanying drawings. However, these descriptions do not constitute a limitation of the present invention and are merely illustrative. The advantages of the present invention will become clearer and easier to understand through this description.

[0050] Referring to the attached drawings, the construction method for the support structure applicable to pipeline groups spanning foundation pits includes the following steps:

[0051] Step 1: First, construct the retaining structure around the foundation pit 11;

[0052] Step 2: Construction of the underground pipeline group to be relocated 10, including two first-stage reinforced concrete supports 1.1 and temporary columns 9 near various underground pipelines;

[0053] Step 3: Excavate the earth and rock near the underground pipeline group 10 to be relocated within the foundation pit 11 with slope protection;

[0054] Step 4: When excavation reaches about 0.5m below the bottom elevation of underground pipeline group 10, manually clean the foundation and level it with plain concrete;

[0055] Step 5: Clear the debris around the temporary column 9 to ensure that the reinforcing steel can pass smoothly through the lattice column 3 later;

[0056] Step 6: Lay steel mesh on the plain concrete foundation, pour concrete and cure to the design strength;

[0057] Step 7: Relocate the underground pipeline group 10 (i.e., various underground pipelines) to the reinforced concrete structural slab 2;

[0058] Step 8: Excavate the foundation pit 11. Install supports in sequence;

[0059] Step 9: Underground structure construction, pouring the bottom slab, side walls, and top slab of the underground structure in sequence from bottom to top;

[0060] Step 10: Backfill the foundation pit 11 surrounding the underground pipeline group 10, and backfill the area below the reinforced concrete structural slab 2 with cement mortar (e.g., Figure 1 , Figure 2 , Figure 3 (As shown).

[0061] This invention only provides a support structure near the pipeline spanning the foundation pit, and the foundation pit support system on the outer side of the pipeline is consistent with the surrounding area.

[0062] Furthermore, the steel lattice material is Q235A steel, the welding rods are E4300~E4313, all steel component connections are full welds, and the weld height is 8mm. The design strength grade of the bored pile concrete is C35.

[0063] Furthermore, in step two, the allowable errors for the construction of temporary columns are: a) the deviation of the main reinforcement spacing should not exceed 10mm, and the deviation of the stirrup spacing should not exceed 20mm;

[0064] b) The diameter deviation of the reinforcing cage should not exceed 10mm, and the length deviation should not exceed 50mm; c) The verticality deviation of the bored piles and steel lattice should not exceed 1 / 300, and the planar position deviation should not exceed 50mm.

[0065] Furthermore, in this step, the deformation control standards for the underground pipeline group 10 are as follows:

[0066] To prevent excessive deformation of various pipelines, when power and telecommunications pipelines are relocated above the foundation pit, their length should be increased by 0.5m to 1.0m compared to the existing line length to prevent pipeline breakage due to excessive support deformation. For water supply and drainage pipes, natural gas pipes, and other pipelines, the deformation control values ​​can refer to the following: cumulative displacement of 10–30mm, variation frequency of 12mm / d, and differential settlement of 0.1%–0.3% L / g (L / g is the pipe section length). To ensure the safe operation of various underground pipelines laid on reinforced concrete structural slabs, deformation must be strictly controlled.

[0067] The pipeline fixing measures are as follows:

[0068] When the pipeline has a circular cross-section, a concrete arc-shaped base needs to be poured before the pipeline is relocated to ensure that the pipeline is subjected to uniform stress and is less prone to shaking, thereby increasing the safety of pipeline operation during the foundation pit construction process.

[0069] Furthermore, in step ten, the backfilling measures under the reinforced concrete structural slab 2 are as follows:

[0070] When the space between the reinforced concrete slab and the underground structure is narrow, in order to facilitate filling the gap between the two, a hole of 200mm to 300mm is reserved in advance on the reinforced concrete slab. After the underground structure is completed, cement mortar is poured through the reserved hole.

[0071] When there is ample space between the reinforced concrete slab and the underground structure, earth and stone are used for backfilling first. To reduce the gap under the reinforced concrete slab, cement mortar is then poured into the pre-reserved holes.

[0072] When backfilling is completed under the reinforced concrete structural slab and on both sides of the pipeline, the pipeline backfilling shall be carried out in accordance with the relevant specifications.

[0073] Referring to the attached drawings, the support structure for spanning pipeline groups in the foundation pit constructed using the aforementioned construction method includes a reinforced concrete support 1, characterized in that it further includes a reinforced concrete structural slab 2 and temporary columns 9.

[0074] The reinforced concrete support 1 is located inside the foundation pit 11;

[0075] The reinforced concrete structural slab 2 is erected in the foundation pit 11 by the temporary columns 9;

[0076] The underground pipeline group 10 is fixed to the reinforced concrete structural slab 2;

[0077] The reinforced concrete support 1 includes a first reinforced concrete support 1.1 and a second reinforced concrete support 1.2;

[0078] The first reinforced concrete support 1.1 consists of multiple supports arranged parallel to each other in the support plane. The plane spacing can be 4m to 6m, and the cross-section can be 800mm×800mm, 800mm×1000mm, etc., which can be determined based on the span of the foundation pit. The supports need to have sufficient rigidity and strength, and meet the structural requirements of the foundation pit support. The supports should be at a consistent elevation and positioned 0.5m above the top of the outer diameter of the pipeline to facilitate subsequent pipeline installation.

[0079] The reinforced concrete structural slab 2 is fully laid between the two reinforced concrete supports 1 in the planar direction, and is arranged below the lowest point of the underground pipeline group 10 in the elevation direction; both ends of the reinforced concrete structural slab 2 pass through the temporary column 9.

[0080] The temporary columns 9 are arranged along the axis of the reinforced concrete supports 1; the temporary columns 9 are respectively arranged at the center of multiple first reinforced concrete supports 1.1 (e.g., Figure 1 , Figure 2 , Figure 3 (As shown).

[0081] Furthermore, the reinforced concrete structural slab 2 is positioned 0.5m below the lowest point of the underground pipeline group 10 in the elevation direction.

[0082] Furthermore, the temporary column 9 includes a steel lattice structure 3 located above the foundation pit 11 and a bored pile 4 located below the foundation pit 11;

[0083] The steel lattice structure 3 is welded from 4×160 angle steel;

[0084] The bored pile 4 is equipped with a steel cage 4.1.

[0085] Furthermore, there are multiple steel lattice structures 3; the multiple steel lattice structures 3 are arranged at intervals along the axis of the reinforced concrete support 1;

[0086] There are multiple bored piles 4; the multiple bored piles 4 are arranged along the axis of the reinforced concrete support 1;

[0087] The reinforcing cage 4.1 is welded to the steel lattice 3 (e.g., Figure 1 , Figure 2 , Figure 3 (As shown).

[0088] Furthermore, both ends of the reinforced concrete structural slab 2 pass through the lattice column 3; at the junction of the reinforced concrete structural slab 2 and the lattice column 3, the transverse and longitudinal reinforcing bars of the structural slab must not be broken, and the gusset plates of the lattice column 3 are staggered vertically from the reinforcing bars of the reinforced concrete structural slab 2.

[0089] Furthermore, the underground pipeline group 10 includes, but is not limited to, water supply and drainage pipes 5, power and telecommunications pipes 6, and natural gas pipes 7 (such as...). Figure 1 , Figure 2 , Figure 3 , Figure 4 (As shown).

[0090] To more clearly illustrate the construction method of the support structure applicable to pipeline groups spanning foundation pits described in this invention, and the advantages of the structure compared with existing technologies, the staff compared the two technical solutions, and the comparison results are shown in the table below:

[0091]

[0092] As can be seen from the table above, the construction method and structure of the support structure applicable to the pipeline group across the foundation pit described in this invention, compared with the prior art, do not require secondary relocation of underground pipelines after adopting the structure of this invention, and the impact of the underground pipelines on the foundation pit plane is small.

[0093] Example

[0094] The present invention will now be described in detail using the example of a foundation pit pipeline group project applied to a subway station in a certain city. This example will also provide guidance for the application of the invention to other foundation pit projects.

[0095] The surrounding terrain of this embodiment is flat, located on the first terrace of the left bank of the Yangtze River, where Quaternary artificial deposits (Q) are distributed. ml ), Quaternary alluvial deposits (Q4) al ), Cretaceous-Paleogene Donghu Group ((KE)dn). The strata from top to bottom are (1-1) miscellaneous fill, (3-1) clay, (3-2) silty clay, (3-5) silty clay, silt, silt interbedded, (4-1) silt, (4-2) fine silt, and (15) conglomerate. The strata within the excavation area of ​​the foundation pit are mainly (1-1) miscellaneous fill, (3-1) clay, and (3-2) silty clay, with a maximum confined water head of 15m at the bottom of the foundation pit.

[0096] The supporting structure spanning the pipeline group in this embodiment includes reinforced concrete supports, reinforced concrete structural slabs, temporary columns, and other structures.

[0097] 1) The first layer of reinforced concrete supports consists of two parallel supports, spaced 4m to 6m apart. The cross-section can be 800mm×800mm, 800mm×1000mm, etc., depending on the span of the foundation pit. These supports must possess sufficient rigidity and strength, and meet the structural requirements for foundation pit supports. The supports should be at the same elevation and positioned 0.5m above the top of the pipeline's outer diameter to facilitate subsequent pipeline installation.

[0098] 2) The reinforced concrete structural slab is supported by temporary columns erected in the foundation pit. In the horizontal direction, it is fully laid between two reinforced concrete supports, and in the vertical direction, it is arranged 0.5m below the lowest point of various underground pipelines. A double-layer steel mesh is used. When the horizontal and vertical steel bars are near the lattice columns, they pass through the steel lattice without being broken, and meet the structural requirements of reinforced concrete. The thickness of the structural slab is 300mm to 500mm. The specific thickness and reinforcement need to be determined based on the spacing of the temporary columns and supports and the load of various pipelines.

[0099] At the junction of the structural slab and the temporary support, the transverse and longitudinal reinforcing bars of the structural slab must not be broken, and the gusset plates of the lattice column must be staggered vertically from the reinforcing bars of the structural slab.

[0100] A certain number of holes are reserved in the structural slab to facilitate filling the gap between the reinforced concrete structural slab and the underground structure.

[0101] 3) Temporary columns: The temporary columns consist of two parts, upper and lower. The upper part of the foundation pit is a steel lattice structure welded from 4×160 angle steel, and the lower part of the foundation pit is a bored pile with a diameter of 800mm. The temporary columns are arranged at the center of the two first supports, along the support axis, with a spacing of 6m to 8m.

[0102] To ensure the verticality of the lattice columns, the reinforcing cage of the lower bored piles should be welded to the upper steel lattice and hoisted together. The gap between the empty piles and the steel columns above the foundation pit surface should be fully backfilled with sand and gravel to ensure the stability of the steel lattice during excavation.

[0103] The steel lattice structure is made of Q235A steel, and the welding rods are E4300 to E4313. All steel components are fully welded, with a weld height of 8mm. The design strength grade of the bored pile concrete is C35.

[0104] Allowable errors in the construction of temporary columns: a) The deviation of the main reinforcement spacing shall not exceed 10mm, and the deviation of the stirrup spacing shall not exceed 20mm;

[0105] b) The diameter deviation of the reinforcing cage should not exceed 10mm, and the length deviation should not exceed 50mm; c) The verticality deviation of the bored piles and steel lattice structures should not exceed 1 / 300, and the planar position deviation should not exceed 50mm.

[0106] 4) Deformation control standards

[0107] To prevent excessive deformation of various pipelines, when power and telecommunications pipelines are relocated above the foundation pit, their length should be increased by 0.5m to 1.0m compared to the existing line length to prevent pipeline breakage due to excessive support deformation. Deformation control values ​​for water supply and drainage pipes, natural gas pipes, etc., can refer to the following values: cumulative displacement of 10–30mm, variation frequency of 12mm / d, and differential settlement of 0.1%–0.3% L / g (L / g is the pipe section length). For the safe operation of various underground pipelines laid on reinforced concrete structural slabs, deformation must be strictly controlled.

[0108] 5) Pipeline fixing measures

[0109] like Figure 4 As shown, when the pipeline has a circular cross-section, a concrete arc-shaped base needs to be poured before the pipeline is relocated to ensure that the pipeline is subjected to uniform stress and is less prone to shaking, thereby increasing the safety of pipeline operation during the foundation pit construction process.

[0110] 6) Backfilling measures under reinforced concrete structural slabs

[0111] When the space between the reinforced concrete slab and the underground structure is narrow, holes of 200mm to 300mm are pre-reserved in the reinforced concrete slab to facilitate filling the gap between them. After the underground structure is completed, cement mortar is poured through the pre-reserved holes.

[0112] When there is ample space between the reinforced concrete slab and the underground structure, earth and stone are used for backfilling first. To reduce the gap under the reinforced concrete slab, cement mortar is poured into the pre-reserved holes.

[0113] 7) Pipeline backfilling measures

[0114] When backfilling is completed under the reinforced concrete structural slab and on both sides of the pipeline, the pipeline backfilling shall be carried out in accordance with the relevant specifications.

[0115] Conclusion: This embodiment eliminates the need for secondary relocation of underground pipelines during construction, reduces the impact of underground pipelines on the foundation pit plan, facilitates construction, and minimizes investment costs.

[0116] All other unspecified parts belong to the prior art.

Claims

1. A construction method applicable to support structures spanning pipeline groups across foundation pits, characterized in that: The support structure applicable to pipeline groups spanning foundation pits includes reinforced concrete supports, reinforced concrete structural slabs, and temporary columns. The reinforced concrete support is located inside the foundation pit; The reinforced concrete structural slab is erected in the foundation pit by means of the temporary columns; The underground pipeline network is fixed to the reinforced concrete structural slab. The reinforced concrete support includes a first reinforced concrete support and a second reinforced concrete support. There are multiple first-level reinforced concrete supports, and these multiple first-level reinforced concrete supports are arranged in parallel in the support plane direction. The reinforced concrete structural slab is fully laid between the two reinforced concrete supports in the planar direction and is arranged below the underground pipeline group in the elevation direction; both ends of the reinforced concrete structural slab pass through the temporary columns; The temporary columns are arranged along the axis of the reinforced concrete support; The temporary columns include a steel lattice structure located at the top of the foundation pit and bored piles located at the bottom of the foundation pit; the bored piles are equipped with steel cages. There are multiple steel lattice structures; the multiple steel lattice structures are arranged at intervals along the axis of the reinforced concrete support; There are multiple bored piles; the multiple bored piles are arranged along the axis of the reinforced concrete support; The reinforcing cage is welded to the steel lattice structure; Both ends of the reinforced concrete structural slab pass through the steel lattice. The steel lattice gussets are staggered vertically with the reinforcing bars of the reinforced concrete slab. The underground pipeline network includes water supply and drainage pipes, power and telecommunications pipes, and natural gas pipes; The construction method consists of the following steps: Step 1: First, construct the retaining structure around the foundation pit; Step 2: Construct the first layer of reinforced concrete supports and temporary columns near the underground pipeline group to be relocated. Step 3: Excavate the earth and rock near the underground pipeline group to be relocated within the foundation pit, slope the excavation. Step 4: When excavation reaches 0.5m below the bottom elevation of the underground pipeline group, manually clean the foundation and level it with plain concrete; Step 5: Clear the debris around the temporary columns to ensure that the reinforcing bars can pass smoothly through the steel lattice later; Step 6: Lay steel mesh on the plain concrete foundation, pour concrete and cure to the design strength; Step 7: Relocate the underground pipeline network to the reinforced concrete structural slab; Step 8: Excavate the foundation pit and erect supports in sequence; Step 9: Underground structure construction, pouring the bottom slab, side walls, and top slab of the underground structure in sequence from bottom to top; Step 10: Backfill the foundation pit around the underground pipeline group; cement mortar is used for backfilling under the reinforced concrete structural slab. The backfilling measures under the reinforced concrete structural slab are as follows. When the space between the reinforced concrete slab and the underground structure is narrow, holes of 200mm to 300mm are pre-reserved in the reinforced concrete slab. After the underground structure is completed, cement mortar is poured through the pre-reserved holes. When there is ample space between the reinforced concrete slab and the underground structure, earth and stone are used for backfilling first, and then cement mortar is poured into the pre-reserved holes. When backfilling is completed under the reinforced concrete structural slab and on both sides of the pipeline, the pipeline backfilling shall be carried out in accordance with the relevant specifications.

2. The construction method for a support structure applicable to a pipeline group spanning a foundation pit according to claim 1, characterized in that: The steel lattice material is Q235A steel, and the welding rods are E4300~E4313.

3. The construction method for a support structure applicable to a pipeline group spanning a foundation pit according to claim 1, characterized in that: The reinforced concrete structural slab is positioned 0.5m below the underground pipeline group in the elevation direction.

4. The construction method for a support structure applicable to a pipeline group spanning a foundation pit according to claim 3, characterized in that: The steel lattice structure is welded from 4×160 angle steel.

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