Early dismantling construction method of enclosure structure for subway group pit construction

Abstract

The application discloses a kind of early dismantling construction methods of retaining structure of near subway group pit construction, comprising: first batch deep foundation pit is constructed by using jump pit construction along the length direction of trestle, after first batch deep foundation pit construction is completed to basement roof, roof is changed to trestle and retaining structure, first batch shallow foundation pit and the earthwork excavation and support of remaining deep foundation pit in the same direction, structure construction that are opposite to first batch deep foundation pit are started;When remaining deep foundation pit in the same direction is constructed to foundation bottom plate, the earthwork excavation and support of deep foundation pit relatively far away from the side of trestle, structure construction are carried out, when construction is to B1 floor, the earthwork excavation and support of second batch shallow foundation pit adjacent to first batch shallow foundation pit, structure construction are carried out;When second batch shallow foundation pit construction completes B1 layer foundation bottom plate, temporary steel slope changes support and side wall, the earthwork excavation and support of remaining shallow foundation pit, structure construction are carried out. Construction trestle can be removed in advance, main structure early construction, early connection can be effectively realized, so as to ensure that structure is completed in advance.

Description

Technical Field

[0001] This invention relates to the field of building construction technology, specifically to a method for early demolition of retaining structures in near-subway pit construction. Background Technology

[0002] In the construction of deep foundation pits near subway stations, it is necessary to excavate, construct, and skip pits in stages. The foundation pits are separated by continuous walls or retaining piles. Deep foundation pits use multi-layer reinforced concrete support technology, while shallow foundation pits use multi-layer steel support technology to ensure the safety and stability of the foundation pits.

[0003] Due to the varying areas and heights of the main structures within each foundation pit, the construction conditions differed significantly. Some pits were undergoing earthwork excavation, others underground structure construction, and still others above-ground structure construction, resulting in extremely complex conditions. For above-ground structure construction, the main structure's external scaffolding needed to be erected synchronously with its progress. Generally, the main structure's external scaffolding started from the B1 level (basement level) floor slab or the basement roof slab, or used cantilevered I-beam scaffolding. However, due to the presence of the construction trestle and partition wall, the above-ground structure on that side had a long cantilever, making it impossible to install cantilevered scaffolding. Therefore, the main structure construction had to be completed first, and the external scaffolding on the trestle and partition wall side dismantled before the trestle and partition wall dismantling could proceed. Consequently, the main structure could not be connected in advance, leading to excessive workload for later main structure connection and the dismantling of the construction trestle and partition wall, severely extending the construction period and increasing costs. Summary of the Invention

[0004] To address the shortcomings of existing technologies, this invention provides an early dismantling system for retaining structures in near-subway pit construction. This system can remove construction trestle bridges in advance, effectively enabling early construction and connection of the main structure, thereby ensuring the structure is completed ahead of schedule.

[0005] The technical solution to achieve the purpose of this invention is as follows:

[0006] A method for early removal of retaining structures during construction near subway tunnels includes the following steps:

[0007] The foundation pit is divided into several deep foundation pits that are relatively far away from the subway tunnel and several shallow foundation pits that are relatively close to the subway tunnel. A construction trestle is set up on the ground floor between the deep foundation pits and the shallow foundation pits. Each deep foundation pit and shallow foundation pit is separated by a retaining structure.

[0008] The first batch of deep foundation pits was constructed by skipping pits along the length of the trestle bridge. After the first batch of deep foundation pits was completed up to the top slab of the basement, the top slab was replaced with supports on the trestle bridge and the retaining structure. Then, the earthwork excavation, support and structural construction of the first batch of shallow foundation pits directly opposite the first batch of deep foundation pits and the remaining deep foundation pits in the same direction were started.

[0009] When the remaining deep foundation pits in the same direction are constructed to the foundation slab, earthwork excavation and support and structural construction of the deep foundation pits on the side relatively far from the trestle bridge will be carried out. When the construction reaches the B1 floor slab, earthwork excavation and support and structural construction of the second batch of shallow foundation pits adjacent to the first batch of shallow foundation pits will begin.

[0010] After the second batch of shallow foundation pit construction is completed, including the B1 layer foundation slab, temporary inclined steel replacement support and side walls, the remaining shallow foundation pits will be excavated and supported, and structural construction will be carried out.

[0011] Once the adjacent foundation slab, temporary inclined steel support and side wall construction are completed, the construction trestle and its underlying retaining structure can be dismantled in advance through overlapping procedures, and the connection construction of the basement structure on both sides of the trestle can be carried out.

[0012] In a preferred embodiment of the present invention, during the construction of shallow foundation pit support, the horizontal temporary steel support in the shallow foundation pit is replaced with a temporary inclined steel support.

[0013] In a preferred embodiment of the present invention, the intercalation process includes:

[0014] The construction trestle is divided into multiple sections along its length. After the foundation of the basement B1 floor and its side walls and temporary inclined steel supports in the shallow foundation pit of each section of the construction trestle are completed, the corresponding section of the construction trestle and its retaining structure below are dismantled. Then, the connection construction of the basement structure of the deep foundation pit and shallow foundation pit on both sides of the dismantled section of the construction trestle is carried out.

[0015] As a preferred embodiment of the present invention, after the construction of the B1 floor slab of the deep foundation pit on the side relatively far away from the trestle bridge is completed, the construction trestle bridge outside the foundation pit and the retaining structure below it are removed, and then the structural construction of the B1 floor and the connection construction with the basement structure in other deep foundation pits are carried out.

[0016] As a preferred embodiment of the present invention, the construction joints are planned in advance during the construction of the main structure in the first batch of deep foundation pits. The structural construction joints are set on the cantilever slabs that are extended outward from the main frame beams on each side of the foundation pit. The external scaffolding of the main structure is erected starting from the cantilever slabs.

[0017] As a preferred embodiment of the present invention, after the construction of the shallow foundation pit underground structure is completed, the construction of the above-ground main structure is carried out directly.

[0018] As a preferred embodiment of the present invention, after the construction of the first floor main structure is completed, a ground-mounted external scaffold is erected to carry out the construction of the second floor main structure.

[0019] As a preferred embodiment of the present invention, once the construction of the second-floor main structure is completed and reaches the required strength, the formwork of the first-floor main structure is removed and an internal passageway is set up for vehicle transportation.

[0020] By adopting the above technical solution, the present invention has the following beneficial effects:

[0021] 1. Under the premise of ensuring that construction transportation in ultra-deep and large foundation pits is not affected, the construction trestle and the retaining structure below it can be dismantled early, thereby ensuring that the main structure is completed ahead of schedule, saving construction time and reducing construction costs.

[0022] 2. This patent enables the early demolition of the construction trestle and retaining structure, and the early connection of the basement structure. This allows for the early construction of the above-ground structure located in the trestle area and the shallow foundation pit to the north, and ensures the effective implementation of the supporting frames, external scaffolding, and other related construction procedures for the above-ground structure in this area, thus ensuring the safe completion of the construction. Attached Figure Description

[0023] To more clearly illustrate the technical solutions in the embodiments of the present invention, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0024] Figure 1 This is a plan view of the retaining structure of the near-subway pit according to an embodiment of the present invention.

[0025] Figure 2 This is a schematic diagram illustrating the division of the near-subway pit area according to the present invention.

[0026] Figure 3 yes Figure 2 Sectional view at point 1-1.

[0027] Figure 4 This is a schematic diagram of an external scaffolding according to an embodiment of the present invention.

[0028] Figure 5 This is a partial structural plan view of the ground floor of an embodiment of the present invention.

[0029] Figure 6 This is a partial structural plan of the two-story above-ground structure according to an embodiment of the present invention.

[0030] Figure 7 This is a schematic diagram of the internal passageway of the external frame according to an embodiment of the present invention.

[0031] The correspondence between the markings in the diagram is as follows:

[0032] 1-Construction trestle; 2-Intermediate diaphragm wall; 21-Triaxial cement mixing pile; 3-Embedded steel pipe; 4-Hanging dense safety net; 5-External scaffolding on cantilever structure; 6-Structural construction joint; 7-Dense safety net; 8-Steel treads laid at each step; 9-Adjustable base; 10-Internal passageway of external scaffolding; 11-Temporary inclined steel support; 12-Wall beam; 13-Brick retaining wall; 14-Drainage ditch; 15-Concrete surface layer; 16-Support; 17-B1 floor slab; 18-B2 floor slab; 19-Foundation slab; 20-Slab cushion layer; 21-Early demolition area of ​​intermediate diaphragm wall. Detailed Implementation

[0033] The technical solutions of this patent embodiment will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of this patent, and not all of them. Based on the embodiments of this patent, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this patent.

[0034] See Figures 1-3 In the construction of deep foundation pits near the subway, it is necessary to excavate, construct, and skip pits in stages. The pits are separated by continuous walls or retaining piles. Deep foundation pits employ multi-layer reinforced concrete support technology, while shallow foundation pits employ multi-layer steel support technology to ensure the safety and stability of the pits. Pit II-1 to II-5 are 17m deep (deep foundation pits), and pits II-6 to II-11 are 9m deep (shallow foundation pits). The deep and shallow foundation pits are connected from the B1 floor slab to form a unified whole. The construction sequence is as follows:

[0035] ① Excavation and support / structural construction of pits II-2 and II-4;

[0036] ②After the construction of the basement roof slab of the pre-excavation pits II-2 and II-4 is completed, the earthwork excavation and support and structural construction of pits II-1 and II-3 will be carried out.

[0037] ③ When the pre-construction pits II-1 and II-3 are backfilled to the basement B3 floor foundation slab, the earthwork excavation and support and structural construction of pit II-5 will be carried out; when the pre-construction pits II-1 and II-3 are backfilled to the basement top slab, the earthwork excavation and support and structural construction of pits II-6, II-8 and II-10 will be carried out.

[0038] ④ After the foundation slab and side walls of the B1 layer of the pre-excavation pits II-6, 8, and 10, as well as the temporary horizontal steel replacement support are completed, the earthwork excavation and support and structural construction of pits II-7, 9, and 11 will be carried out.

[0039] ⑤ After the construction of the basement roof slab of pits II-6 to II-11 is completed, the central partition wall and construction trestle will be demolished. The central partition wall will be demolished layer by layer from top to bottom, and the main structure will be connected layer by layer accordingly.

[0040] Due to the varying areas and structural heights of the different foundation pits, the construction conditions differ from pit to pit. Some pits are undergoing earthwork excavation, some are undergoing underground structure construction, and some are undergoing above-ground structure construction, making the construction conditions extremely complex. For above-ground structure construction, the scaffolding of the main structure must be constructed upwards in tandem with its progress. Generally, the scaffolding for the main structure starts from the B1 floor slab or the basement roof slab, or uses cantilevered I-beam scaffolding. However, due to the presence of the construction trestle and the central partition wall, the above-ground structure on this side has a long cantilever, making it impossible to install cantilevered scaffolding. Therefore, the main structure construction must be completed first, and the scaffolding on the trestle and central partition wall side must be dismantled before the trestle and central partition wall dismantling can proceed. For example, the construction trestle and central partition wall in pit II-4 can only be dismantled after the main structure construction of pit II-4 is completed and the scaffolding on its north side is dismantled.

[0041] There are some above-ground structures in pits II-6 to II-11. Above-ground structure construction can only be carried out after the construction trestle and central partition wall are demolished and the underground structure construction of pits II-6 to II-11 is completed. The entire construction process is extremely complex, and the difficulty of subsequent connection and the amount of work are enormous, resulting in a very long construction period.

[0042] In summary, the above-mentioned construction procedures in the existing technology have the following disadvantages:

[0043] 1) The entire foundation pit is divided into multiple smaller foundation pits, with separate excavation, separate construction, and skip-pit construction. The main structure needs to be constructed in batches according to the excavation sequence of the foundation pits. The process is complex and the construction period is long. There is a construction trestle bridge in the foundation pit that serves as a temporary road. It cannot be dismantled with the current technology, so the main structure cannot be connected in advance. The workload of connecting the main structure in the later stage, as well as the workload of dismantling the construction trestle bridge and partition walls, is too large, which seriously prolongs the construction period and increases the construction cost.

[0044] 2) The existing technology for demolishing the partition wall requires that the main structure in the foundation pit on both sides of the trestle bridge be constructed to the top slab and the external scaffolding in the demolition work area be removed before the demolition can be carried out in a retreat manner. The main structure in the demolition work area cannot be constructed, and the transportation of waste materials after demolition is quite difficult.

[0045] 3) The cantilever length of the main structure located on the north side of the trestle bridge is 3m-4m. Only ground-supported scaffolding can be used for the external scaffolding of the main structure. The external scaffolding must be dismantled before the trestle bridge is demolished to prevent large machinery from colliding with the scaffolding or large pieces of waste concrete from collapsing it during the demolition of the central partition wall and the trestle bridge. After the trestle bridge is demolished, the basement main structure will be connected to it; construction of the above-ground structure in this area will only proceed after the connection strength meets design requirements. This not only involves complex construction techniques and significantly extends the construction period but also affects other professional construction work.

[0046] Therefore, this invention proposes a method for early demolition of retaining structures in near-subway pit construction. The objectives are: 1) to enable early demolition of the construction trestle and its underlying retaining structure while ensuring uninterrupted transportation during construction in ultra-deep, large pits, thereby ensuring the early completion of the main structure, saving time, and reducing construction costs; 2) to achieve early demolition of the construction trestle and retaining structure, and early connection of the basement structure. This allows for early construction of the above-ground structures located in the trestle area and the shallow pit to the north, and ensures the effective implementation of related construction procedures such as support frames and external scaffolding for the above-ground structures in this area, guaranteeing the safe completion of the construction.

[0047] Specifically, for the construction of deep and shallow foundation pits near the subway, to ensure the safety of the subway tunnel and urban main roads outside the pits, a method of asynchronous and segmented construction of deep and shallow foundation pits was adopted, dividing the foundation pits into 11 pits of varying sizes. The horizontal temporary steel supports in the shallow foundation pits II-6 to II-11 on the north side, adjacent to the subway tunnel, were replaced with temporary inclined steel supports (11). Figure 3 As shown, the early removal process of the central partition wall facilitates the early removal of the central partition wall. The deep foundation pits II-1 to II-5 on the south side, which are relatively far from the subway tunnel, adopt the method of excavation, construction, and skipping pits. The foundation pits are separated by a central continuous wall or retaining pile, and multiple reinforced concrete support technology is used to ensure the safety and stability of the foundation pits.

[0048] 1. Construction sequence:

[0049] ① Divide the foundation pit into several deep foundation pits (II-1~5 foundation pits) that are relatively far away from the subway tunnel and several shallow foundation pits (II-6~11 foundation pits) that are relatively close to the subway tunnel. A construction trestle bridge 1 is set up on the ground floor between the deep foundation pits and the shallow foundation pits. Each deep foundation pit and shallow foundation pit is separated by a retaining structure. The retaining structure can be a continuous wall 2 with a central partition wall or a retaining pile (such as a three-axis cement mixing pile 21).

[0050] ② Along the length of the trestle bridge 1, the first batch of deep foundation pits (II-2 and II-4 foundation pits) were constructed by skipping pits. After the first batch of deep foundation pits were completed up to the top slab of the basement, the top slab was replaced with supports on the trestle bridge and the retaining structure. The earthwork excavation, support and structural construction of the first batch of shallow foundation pits (II-11 and II-8 foundation pits) directly opposite the first batch of deep foundation pits and the remaining deep foundation pits (II-1 and II-3 foundation pits) in the same direction were then carried out.

[0051] ③ When the remaining deep foundation pits (II-1 and II-3) in the same direction are constructed to the bottom layer (B3-underground level 3 in this embodiment) foundation slab, earthwork excavation and support and structural construction of the deep foundation pit (II-5) on the side relatively far away from the trestle bridge will be carried out. When the II-1 and II-3 foundation pits are constructed to the B1 floor (underground level 1) floor slab, earthwork excavation and support and structural construction of the second batch of shallow foundation pits (II-7 and II-10) adjacent to the first batch of shallow foundation pits will begin.

[0052] ④ After the second batch of shallow foundation pits (II-7 and II-10) have completed the B1 layer foundation slab, temporary inclined steel support and side walls, the earthwork excavation and support and structural construction of the remaining shallow foundation pits (II-6 and II-9) will be carried out.

[0053] Once the adjacent foundation slab, temporary inclined steel support and side wall construction are completed, the construction trestle and its underlying retaining structure can be dismantled in advance through overlapping procedures, and the connection construction of the basement structure on both sides of the trestle can be carried out.

[0054] In the construction of shallow foundation pit support, the horizontal temporary steel supports in the shallow foundation pit are replaced with temporary inclined steel supports.

[0055] 2. Interleaving process:

[0056] The construction trestle is divided into multiple sections along its length. After the foundation of the basement B1 floor and its side walls and temporary inclined steel supports in the shallow foundation pit of each section of the construction trestle are completed, the corresponding section of the construction trestle and its retaining structure below are dismantled. Then, the connection construction of the basement structure of the deep foundation pit and shallow foundation pit on both sides of the dismantled section of the construction trestle is carried out.

[0057] Specifically, in this embodiment, the intercalation process includes:

[0058] ①After the construction of the foundation slab and side walls of the basement B1 floor in pits II-10 and II-11, as well as the temporary inclined support, is completed, the first part of the construction trestle and the underground continuous wall below it can be removed, and then the connection construction of the basement structure on the north and south sides can be carried out.

[0059] ② Once the foundation slab and side walls of the basement level B1 in pits II-6 to II-9, as well as the temporary diagonal supports, are completed (pits II-7 and II-8 have already been completed), the second part of the construction trestle and the underground continuous wall beneath it can be dismantled. Simultaneously, the structural connection construction of the basements on the north and south sides of this area can begin (there is sufficient safety distance between the basement roof slab and the construction trestle on the north side of this area, allowing for simultaneous construction). The second part of the trestle can be dismantled at multiple points simultaneously. The existing trestle and the completed basement roof slab on the north side will serve as a temporary access road for waste removal and material transportation during structural construction.

[0060] ③ After the second part of the construction trestle is demolished, the third part of the construction trestle and the underground continuous wall below it can be demolished, and then the connection construction of the basement structure can be carried out.

[0061] ④ After the construction of the B1 floor slab in Pit II-5 is completed, the fourth part of the construction trestle outside the pit and the retaining piles below it can be removed, and then the structural construction of the B1 floor and the connection construction with the structure on the south side can be carried out.

[0062] By implementing overlapping construction processes, the construction trestle and the underground continuous wall beneath it can be dismantled simultaneously with the construction of the II-6~11 pits on the north side, thereby achieving early dismantling of the construction trestle and early connection of the structure.

[0063] 3. Other construction techniques related to the main structure:

[0064] ①The construction joints of the main above-ground structure in pits II-2 and II-4 need to be planned in advance. Construction joint 6 should be set 2m outside the main frame beams on each side adjacent to the pit (taking pit II-4 as an example, see Figure 4 The main structure's external scaffolding is erected starting from this 2m wide cantilever slab. The inner edge of the external scaffolding is 30cm from the structural construction joint (this ensures the safety of the structure and external scaffolding, and also allows for direct removal of the trestle bridge and central partition wall). Figure 4 As shown.

[0065] ② After the underground structure construction of pits II-6 to II-11 is completed, the main above-ground structure construction can proceed directly. The outer edge of the formwork for the first-floor main structure inside the pit is 5.7m from the edge of the outer foundation pit. Figure 5 As shown, this will not obstruct traffic within the site. Once the first-floor structure is completed, a ground-supported external scaffold can be erected (the inner side of the scaffold should be 30cm from the outer edge of the second-floor structure) before proceeding with the construction of the second-floor main structure.

[0066] ③ Due to the long cantilever of the main structure on the second floor and above (approximately 3-4 meters), it is not feasible to install cantilevered external scaffolding. Instead, the scaffolding will be erected upwards from the first floor external scaffolding. The first floor external scaffolding will not be dismantled until the main structure in this area is completed. Once the second floor structure is completed and reaches the design strength requirements, the first floor structural formwork can be dismantled, and an internal passageway 10 will be provided within the external scaffolding to allow for vehicle transport. Some miscellaneous materials can be stacked on the outside of the external scaffolding. Figure 6 and Figure 7 As shown.

[0067] The early demolition construction method for retaining structures in near-subway multi-pit construction of this invention, in order to ensure the safety of the subway tunnel and urban main roads outside the pits during the construction of deep and shallow foundation pits near the subway, adopts a method of asynchronous and segmented construction of deep and shallow foundation pits, dividing the foundation pits into 13 pits of different sizes. After the first batch of foundation pits II-2 and II-4 are completed up to the basement roof slab, the roof slab is replaced with supports to the trestle bridge and central partition wall, and earthwork excavation, support, and structural construction of pits II-11 north of pit II-4, pit II-8 directly north of pit II-2, and pits II-1 and II-3 begin. When pits II-1 and II-3 are constructed up to the B3 floor foundation slab, earthwork excavation, support, and structural construction of pit II-5 begin. When pits II-1 and II-3 are constructed up to the B1 floor slab, earthwork excavation, support, and structural construction of pits II-7 and II-10 begin. After the B1 foundation slab, temporary inclined steel supports, and side walls of pits II-7 and II-10 are completed, earthwork excavation and support and structural construction of pits II-6 and II-9 can begin. Following the completion of the foundation slabs, temporary inclined steel supports, and side walls of each preceding pit, the construction trestle and its underlying central partition wall structure can be dismantled ahead of schedule through overlapping construction processes. Simultaneously, by utilizing other main structural construction techniques, early construction of the above-ground structures located in the trestle area and the shallow pit to the north can be achieved, ensuring the effective implementation of the supporting frames and external scaffolding for the above-ground structures in this area, and guaranteeing the safe completion of the structural construction.

[0068] The early dismantling construction method for retaining structures in near-subway pit construction of this invention enables the early dismantling of construction trestle bridges and the retaining structures below them, while ensuring that construction and transportation in ultra-deep and large pits are not affected, thereby ensuring the early completion of the main structure. Simultaneously, the erection of external scaffolding for the main structure is carried out while ensuring safety and on-site transportation, thus ensuring the smooth completion of the main structure.

[0069] Although embodiments of this patent have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of this patent, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A method for early dismantling of a containment structure for a near-ground subway open-cut construction, characterized in that, The method comprises the following steps: The foundation pit is divided into multiple deep foundation pits relatively far from the subway tunnel and multiple shallow foundation pits relatively close to the subway tunnel, a construction trestle is arranged on the ground floor between the deep foundation pits and the shallow foundation pits, and a support structure is arranged between each deep foundation pit and shallow foundation pit; The first deep foundation pit is constructed by using the skip construction along the length direction of the trestle, after the first deep foundation pit is constructed to the basement roof, the roof support is replaced to the trestle and the support structure, and the soil excavation and support and structure construction of the first shallow foundation pit opposite to the first deep foundation pit and the remaining deep foundation pits in the same direction are started; When the remaining deep foundation pits in the same direction are constructed to the foundation bottom plate, the soil excavation and support and structure construction of the deep foundation pit relatively far from the trestle are carried out, and when the construction is carried out to the B1 floor, the soil excavation and support and structure construction of the second shallow foundation pit adjacent to the first shallow foundation pit are started; After the second shallow foundation pit is constructed to the B1 foundation bottom plate and the side wall, the soil excavation and support and structure construction of the remaining shallow foundation pit are carried out; After the adjacent foundation bottom plate, the temporary inclined steel support and the side wall are constructed, the construction trestle and the support structure below the construction trestle are removed in advance by inserting the process, and the connection construction of the basement structures on both sides of the trestle is carried out; In the support construction of the shallow foundation pit, the horizontal temporary steel support in the shallow foundation pit is replaced by the temporary inclined steel support; The inserting process comprises: The construction trestle is divided into multiple parts along the length direction, after the basement B1 foundation and the side wall, the temporary inclined steel support of the shallow foundation pit corresponding to each part of the construction trestle are constructed, the corresponding part of the construction trestle and the support structure below the corresponding part of the construction trestle are removed, and the connection construction of the basement structures of the deep foundation pit and the shallow foundation pit on both sides of the removed part of the construction trestle is carried out.

2. The early demolition construction method of a retaining structure of near-geared pitting construction according to claim 1, characterized by, After the B1 floor of the deep foundation pit relatively far from the trestle is constructed, the construction trestle outside the foundation pit and the support structure below the construction trestle are removed, and the structure construction of the B1 floor and the connection construction of the basement structure in other deep foundation pits are carried out.

3. The method of claim 1, wherein, The construction joint is planned in advance when the main structure of the ground above the first deep foundation pit is constructed, the structure construction joint is arranged outside the main frame beam of each side of the foundation pit, the cantilever plate is arranged by expanding the main frame beam, and the outer scaffolding of the main structure is erected from the cantilever plate.

4. The early demolition construction method of a retaining structure of a near-geared pitting construction according to claim 3, characterized by, After the underground structure of the shallow foundation pit is constructed, the main structure of the ground above is directly constructed.

5. The method of claim 4, wherein, After the main structure of the ground above the first floor is constructed, the outer scaffolding of the main structure of the ground above the second floor is erected, and the main structure of the ground above the second floor is constructed.

6. The method of claim 5, wherein the method further comprises: After the main structure of the ground above the second floor is constructed and the required strength is reached, the formwork support of the main structure of the ground above the first floor is removed, and the inner passage of the outer scaffolding is arranged to provide a vehicle transportation passage.

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