Construction method of staggered water flow in underground earthwork structure of reverse engineering

Abstract

The present invention discloses a construction method for staggered water flow in underground earthwork structures of reverse engineering, comprising the following steps: dividing the foundation pit to be constructed area into area A and area B, further dividing area A into area A1 inside the foundation pit and area A2 located around the foundation pit; excavating area A1 and area B, and excavating to between the first underground floor and the second underground floor, and then constructing the structural beams and slabs of the first underground floor in area A1 and area B; after the structural beams and slabs of the first underground floor in area A1 and area B reach the design strength, excavating area A2, and excavating to between the first underground floor and the second underground floor, and then constructing the side span structure of area A2, and connecting the side span structure of area A2 to the structural beams and slabs of the first underground floor in area A1. The present invention solves the technical problem that the reverse construction method of the foundation pit in the prior art is a whole-layer operation method, which seriously increases costs. The rotating operation method of the present invention allows large-scale machinery of the labor force to work crosswise, and there is no problem of stagnation of work types, and the underground water flow operation and the surface water flow operation do not interfere with each other.

Description

Technical Field

[0001] The present invention relates to the field of building construction, and in particular to a construction method for staggered water flow in an underground earthwork structure of a reverse engineering project. Background Art

[0002] Top-down construction technology is currently the most advanced construction technique for high-rise buildings. In the context of rapid urbanization, top-down construction, with its ability to construct both above- and underground structures simultaneously, has significantly impacted project duration, costs, and economic and social benefits. The top-down construction structure floor slab serves as the horizontal support for the foundation pit, offering high rigidity, minimal deformation of the retaining structure, and minimal impact on the surrounding environment. However, deep foundation pit construction carries a high safety risk due to excavation and structural work within a confined space. In urban core areas with complex surrounding environments and limited sites, the top-down construction zero-level slab structure can serve as a working platform, increasing site utilization and facilitating construction organization. The traditional full-top-down underground construction process involves excavating one layer of earthwork, then constructing the beam-slab structure. Once the entire beam-slab concrete layer reaches its design strength, excavation of the next layer can begin, and so on. This process results in significant technical interruptions for structural and earthwork personnel and machinery, leading to a period of rapid, "peak-and-trough" switching between personnel and machinery, hindering streamlined operations and significantly increasing costs. Summary of the Invention

[0003] In response to the above-mentioned shortcomings in the existing technology, the present invention provides a construction method for staggered water flow in underground earthwork structures of reverse engineering, which solves the technical problem that the reverse construction method of foundation pit in the existing technology is a whole-layer operation mode, which seriously increases the cost.

[0004] The present invention discloses a construction method for staggered water flow in an underground earthwork structure of a reverse engineering project, comprising the following steps:

[0005] The area to be constructed in the foundation pit is divided into Area A and Area B. Area A is further divided into Area A1 located inside the foundation pit and Area A2 located around the foundation pit.

[0006] Excavate Area A1 and Area B to the area between the first and second underground floors, and then construct the structural beams and slabs of the first underground floor of Area A1 and Area B;

[0007] After the structural beams and slabs of the first underground floor in Area A1 and Area B reach the design strength, the A2 area will be excavated and excavated to the area between the first underground floor and the second underground floor. The side span structure of Area A2 will then be constructed and connected to the structural beams and slabs of the first underground floor in Area A1.

[0008] Excavate area B to the area between the second and third underground floors;

[0009] After the side span structure of Area A2 reaches the design strength, Area A will be excavated to the area between the second and third underground floors, and the second underground floor structural beams and slabs of Area B will be constructed at the same time;

[0010] After the structural beams and slabs of the second underground floor in Area B reach the designed strength, excavate Area B and excavate to between the third and fourth underground floors. Simultaneously, the structural beams and slabs of the second underground floor in Area A are constructed.

[0011] Similarly, excavate areas A and B alternately and construct them in staggered layers until the construction of the bottom structural beams and slabs is completed.

[0012] The construction method of the reverse engineering underground earthwork structure with staggered water flow of the present invention is further improved in that, before excavating the A1 area and the B area, an underground continuous wall and a pile foundation in the foundation pit are constructed in the foundation pit.

[0013] The construction method of the reverse engineering underground earthwork structure staggered water flow of the present invention is further improved in that temporary side beams are set around the foundation pit when constructing the underground structural beams and slabs of area A1 and area B.

[0014] The construction method of the reverse engineering underground earthwork structure staggered water flow of the present invention is further improved in that, when excavating the A1 area and the B area, the A2 area is excavated to the space between the top plate and the floor of the underground first floor;

[0015] When constructing the structural beams and slabs of the first underground floor in Areas A1 and B, first construct the first underground floor in Areas A1 and B, then construct the basement top slabs in Areas A and B, and construct the support beams for the upper shear walls on the basement top slab in Area A2, and reserve dowel bars for the shear walls.

[0016] The construction method of the reverse engineering underground earthwork structure staggered water flow of the present invention is further improved in that after the construction of the A2 area side span structure is completed, the A2 area side span structure is connected to the buildings around the foundation pit using a force transmission structure.

[0017] Compared with existing technologies, the present invention has a positive and significant effect. By rotating operations in two zones, the present invention solves the technical problem of the prior art of reverse excavation in the foundation pit, which severely increases costs by operating the entire layer. The present invention's rotating operation method allows large-scale machinery to work in parallel, eliminating the problem of work stagnation. It also ensures that underground and surface water flow operations do not interfere with each other, reducing the input of personnel and machinery and shortening the construction period. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the following briefly introduces the drawings required for use in the description of the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0019] Figure 1 It is a plan view of the construction method of reverse engineering underground earthwork structure staggered water flow of the present invention.

[0020] Figure 2 This is a schematic diagram before excavation of the construction method of the reverse engineering underground earthwork structure staggered water flow of the present invention.

[0021] Figure 3 It is a schematic diagram of the construction method of reverse engineering underground earthwork structure staggered water flow of the present invention, in which the middle part of the foundation pit is excavated to between the underground first floor structure beam slab and the underground second floor structure beam slab.

[0022] Figure 4 This is a schematic diagram of the completion of the basement top plate construction of the reverse engineering underground earthwork structure staggered water flow construction method of the present invention.

[0023] Figure 5 This is a schematic diagram of the excavation between the underground second-layer structural beam and slab and the underground third-layer structural beam and slab in the second zone of the reverse engineering underground earthwork structure staggered water flow construction method of the present invention.

[0024] Figure 6 This is a schematic diagram of the excavation between the underground second-story structural beam and slab and the underground third-story structural beam and slab in the first zone of the reverse engineering underground earthwork structure staggered water flow construction method of the present invention.

[0025] Figure 7 This is a schematic diagram of the excavation below the third underground structure beam and slab in the second zone of the reverse engineering underground earthwork structure staggered water flow construction method of the present invention.

[0026] Figure 8 This is a schematic diagram of the excavation below the first underground three-layer structure beam and slab in the reverse engineering underground earthwork structure staggered water flow construction method of the present invention.

[0027] Among them: A, the first zone; B, the second zone; 1. cast-in-place piles; 2. steel pipe columns; 3. shear wall underpinning columns; 4. underground continuous wall; 5. underground first floor structural beams and slabs; 6. basement roof; 7. shear wall underpinning beams; 8. shear wall reserved dowels; 9. force transmission structure; 10. underground second floor structural beams and slabs; 11. underground third floor structural beams and slabs DETAILED DESCRIPTION

[0028] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0029] like Figures 1 to 8 As shown, the present invention provides a construction method for staggered water flow in an underground earthwork structure of a reverse engineering, comprising the following steps: dividing the foundation pit to be constructed area into area A and area B, further dividing area A into area A1 inside the foundation pit and area A2 located around the foundation pit; excavating area A1 and area B to the area between the first underground floor and the second underground floor, and then constructing the structural beams and slabs 5 of the first underground floor in area A1 and area B; after the structural beams and slabs 5 of the first underground floor in area A1 and area B reach the design strength, excavating area A2 to the area between the first underground floor and the second underground floor, and then constructing the side span structure of area A2, and connecting the side span structure of area A2 with the structural beams and slabs 5 of the first underground floor in area A1. Then, excavate Area B to the area between the second and third underground floors; after the side span structure of Area A2 reaches the design strength, excavate Area A to the area between the second and third underground floors, and simultaneously construct the second underground floor structural beams and slabs 10 of Area B; after the second underground floor structural beams and slabs 10 of Area B reach the design strength, excavate Area B to the area between the third and fourth underground floors, and simultaneously construct the second underground floor structural beams and slabs 10 of Area A; after the second underground floor structural beams and slabs 10 of Area A reach the design strength, excavate Area A to the area between the third and fourth underground floors, and simultaneously construct the third underground floor structural beams and slabs 11 of Area B; and construct the third underground floor structural beams and slabs 11 of Area A. In this embodiment, the underground floor has three floors. Area B can be left undivided or divided into Areas B1 and B2 according to the actual situation on site, and the construction method is the same as that of Areas A1 and A2. Since the method of the present invention excavates area B of A1 first and leaves the soil in area A2 unexcavated, the soil in area A2 can achieve a counter-pressure effect to balance the force exerted by the soil around the foundation pit on the foundation pit.

[0030] The traditional reverse construction method involves pouring the entire floor slab simultaneously and excavating the entire earthwork layer simultaneously. However, during the earthwork operation, the traditional whole-floor construction method cannot be used for large-scale construction of the building structure. During structural construction, if the concrete strength does not reach 80%, the overall support stability cannot be guaranteed, and earthwork construction cannot be carried out. The present invention, however, uses the time it takes for concrete in one area to reach the required strength after pouring to proceed with underground earthwork excavation in another area. The force transmission method is changed to half soil and half concrete slab, which provide mutual force support. This prevents force gaps and thus avoids deformation of the foundation pit and the structure within it. By dividing the entire floor construction into left and right flow operations, labor and large machinery can be used in parallel, reducing time and costs. There is no stagnation in work, and underground and above-ground flow operations do not interfere with each other. This avoids situations where workers spend one month on the site and excavation for another month. This avoids periods of intense labor concentration, followed by the return of all earthwork machinery only after the construction workers have left, forcing construction workers to return repeatedly. In addition, the reverse excavation method is too difficult and time-consuming, and the concrete pouring time and the strength waiting period after concrete construction are also long. The present invention designs a flow operation construction method by making the concrete pouring time and the strength waiting period after concrete construction similar.

[0031] Preferably, before the central portion of the foundation pit is sloped and excavated to the elevation of the underground working surface, and before excavating Areas A1 and B, an underground diaphragm wall 4 and a pile foundation are constructed within the foundation pit. The pile foundation comprises engineering columns and cast-in-place piles 1, upon which steel pipe columns 2 are constructed. This facilitates the subsequent construction of each underground beam and slab layer, while also stabilizing the soil below the foundation pit and preventing displacement that could affect the stability of surrounding buildings. In this embodiment, the steel pipe columns 2 and cast-in-place piles 1 are constructed one column at a time.

[0032] Preferably, temporary side beams are set around the foundation pit when constructing the structural beam slab 5 of the underground first floor in Area A1 and Area B. The temporary side beams can reinforce the periphery of the foundation pit and ensure the stability of the periphery of the foundation pit.

[0033] Preferably, when excavating Areas A1 and B, Area A2 is excavated to the area between the top and floor of the first underground floor. When constructing the structural beam slabs 5 of the first underground floor of Areas A1 and B, the first underground floor of Areas A1 and B is constructed first, followed by the top slabs 6 of the basement in Areas A and B. Shear wall underpinning beams 7 of the upper shear wall are constructed on the top slab 6 of the basement in Area A2, and dowel bars 8 are reserved for the shear wall. This facilitates the subsequent construction of the shear wall and provides a horizontal force transmission structure for the foundation pit. When constructing the shear wall at the location of one column and one pile, shear wall underpinning columns 3 are used instead of steel pipe columns 2 for construction.

[0034] Preferably, after the construction of the side span structure of area A2 is completed, the side span structure of area A2 is connected to the buildings around the foundation pit using a force transmission structure 9. The force transmission structure 9 can also be constructed at the same time as the side span structure as needed, or the side span structure can be directly constructed as the force transmission structure 9. The specific structure of the force transmission structure 9 is a concrete beam, a concrete slab and a concrete column. Since the foundation pit is often located in a space-constrained location and there are other buildings close to the foundation pit, when constructing the force transmission structure 9, the ground-connected wall is removed and the force transmission structure 9 is fixed to the main structure of the existing surrounding buildings, so that the force transmission structure 9 can directly transmit the force in the foundation pit to the surrounding buildings, reducing the strength of the force on the structure in the foundation pit.

[0035] The present invention solves the technical problem of the existing technique of reverse excavation in the foundation pit, which severely increases costs by operating the entire layer, by alternating operations between two areas. The alternating operation method of the present invention allows large-scale machinery to work in parallel, eliminating the problem of work stalls. Furthermore, the underground and surface water flow operations do not interfere with each other, reducing the input of manpower and machinery and shortening the construction period.

[0036] The parts not mentioned in the present invention are the same as the existing technology or can be implemented by using the existing technology. The above description is only the preferred embodiment of the present invention and does not limit the present invention in any form. Although the present invention has been disclosed as the preferred embodiment as above, it is not used to limit the present invention. Any technician familiar with this profession can make some changes or modifications to the equivalent embodiments of equivalent changes by using the technical content disclosed above without departing from the scope of the technical solution of the present invention. However, any simple modification, equivalent change and modification made to the above embodiment based on the technical essence of the present invention without departing from the content of the technical solution of the present invention still falls within the scope of the technical solution of the present invention.

Claims

1. A construction method for staggered water flow in underground earthwork structure of reverse engineering, characterized in that: The steps include: The area to be constructed in the foundation pit is divided into Area A and Area B. Area A is further divided into Area A1 located inside the foundation pit and Area A2 located around the foundation pit. Excavate Area A1 and Area B to the area between the first and second underground floors, and then construct the structural beams and slabs of the first underground floor of Area A1 and Area B; After the structural beams and slabs of the first underground floor in Area A1 and Area B reach the designed strength, Area A2 is excavated and excavated to between the first underground floor and the second underground floor. The side span structure of Area A2 is then constructed and connected to the structural beams and slabs of the first underground floor in Area A1. Excavate area B to the area between the second and third underground floors; After the side span structure of Area A2 reaches the design strength, Area A will be excavated to the area between the second and third underground floors, and the second underground floor structural beams and slabs of Area B will be constructed at the same time; After the structural beams and slabs of the second underground floor in Area B reach the designed strength, excavate Area B and excavate to between the third and fourth underground floors. Simultaneously, the structural beams and slabs of the second underground floor in Area A are constructed. In this way, excavate alternately and construct Area A and Area B in staggered layers until the construction of the bottom structural beams and slabs is completed; When excavating Areas A1 and B, excavate Area A2 to between the top and floor of the first underground floor; When constructing the structural beams and slabs of the first underground floor in Areas A1 and B, first construct the first underground floor in Areas A1 and B, then construct the basement top slabs in Areas A and B, and construct the support beams for the upper shear walls on the basement top slab in Area A2, and reserve dowel bars for the shear walls.

2. The construction method of reverse engineering underground earthwork structure staggered water flow according to claim 1, characterized in that: Before excavating Area A1 and Area B, underground continuous walls and pile foundations are constructed in the foundation pit.

3. The construction method of reverse engineering underground earthwork structure staggered water flow according to claim 1, characterized in that: When constructing the structural beams and slabs of the underground first floor in Area A1 and Area B, temporary side beams are set up around the foundation pit.

4. The construction method of reverse engineering underground earthwork structure staggered water flow according to claim 1, characterized in that: After the construction of the side span structure of area A2 is completed, the side span structure of area A2 is connected to the buildings around the foundation pit using a force transmission structure.

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