A method for synchronous construction of high and low parts of a stepped underground structure

Abstract

The application provides a method for synchronous construction of high and low parts of a stepped underground structure. In the construction stage of a first floor slab in a non-overhead area of the underground structure and a second floor slab in an overhead area, a temporary formwork support frame is used to support the formwork of the first floor slab and the formwork of the second floor slab, so that the underlying area of the pile cap and the structure (horizontal and vertical structure) in the adjacent basement area are integrally poured at the same time, and the integral horizontal structure construction in the underlying area of the pile cap is not required to be performed after the completion of the backfilling of the underlying area of the pile cap (that is, the construction of the underlying area of the pile cap is synchronized with the progress of the adjacent basement structure, and there is no disconnection), so that the construction period is maximally saved, and the total construction period is at least saved by 21 days.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of civil building residential engineering, and particularly relates to a method for synchronous construction of high and low parts of a ladder type underground structure. BACKGROUND

[0002] Under the background of rapid urbanization, it is necessary to improve the utilization rate of construction land as much as possible and ensure the demand for underground parking spaces. In order to meet the requirement of the construction unit that the planning area is not exceeded and ensure the demand for underground parking spaces, the design unit designs a pile cap understructure in response to the requirement of the construction unit.

[0003] The pile cap understructure can achieve the following two purposes: 1) saving the cost of the enclosure of the high and low difference part of the underground structure; and 2) the pile cap understructure can meet the requirement of the construction unit that the area of the basement is optimized and the sales area of the non civil defense area is increased. The reason is that the pile cap understructure area can not be used as the area of the basement. If the pile cap understructure area is used as the area of the basement, the hidden cost of the developer will be increased (the pile cap understructure area needs to increase the raft foundation and other decoration and finishing cost), and the area is not easy to be used as functional housing or planning parking space due to the relationship of the shear wall.

[0004] Usually, the shear wall plate is used as the vertical force transmission connection between the pile cap and the bottom plate of the pile cap understructure area. In order to meet the construction quality of the structure and the waterproof capacity of the bottom plate, the traditional construction method of the pile cap understructure area is: earthwork excavation, cushion pouring, pile cap and raft foundation construction, column structure construction, maintenance, backfilling, cushion pouring, waterproof construction, floor beam plate construction and upper structure construction.

[0005] However, since the pile cap understructure area and the adjacent basement are in the main building area, after the main structure of the adjacent basement is formed, the overall horizontal structure construction needs to wait until the backfilling of the pile cap understructure area is completed. Therefore, the construction of the pile cap understructure area according to the traditional construction method is out of step with the construction of the adjacent basement structure, and the construction progress of the two area structures is about 20-30 days apart, which affects the key route of the project and leads to the increase of the construction period.

[0006] Therefore, how to improve the construction speed of the ladder type underground structure is a technical problem that needs to be solved by those skilled in the art. SUMMARY

[0007] The purpose of the present application is to provide a method for synchronous construction of high and low parts of a ladder type underground structure, which can improve the construction speed of the main structure of the pile cap understructure area.

[0008] In order to solve the above technical problem, the present application provides a method for synchronous construction of high and low parts of a ladder type underground structure, which comprises the following steps:

[0009] S1: according to the construction scheme, after the basement foundation pit is excavated to the soil layer at the bottom of the foundation, the cushion, the pile cap 6 construction and the underground structure construction are sequentially performed on the soil layer at the bottom of the foundation; wherein, the underground structure construction comprises:

[0010] S11: synchronously constructing the columns 5 and the outer walls 4 in the non-suspended area and the suspended area;

[0011] S12: synchronously constructing the first floor slab in the non-suspended area and the second floor slab in the suspended area; wherein, during the construction of the first floor slab and the second floor slab, a temporary formwork support frame is set at the bottom of the formwork of the first floor slab and the formwork of the second floor slab; a construction opening is reserved on the second floor slab;

[0012] S13: after the structures in the non-suspended area and the suspended area are cured to the design strength, the temporary formwork support frame at the bottom of the formwork of the first floor slab and the formwork of the second floor slab is removed, waterproofing is performed on the interior of the suspended area, and the upper structure in the upper region of the non-suspended area and the suspended area is synchronously constructed;

[0013] S2: after the waterproofing of the interior of the suspended area is completed, the construction of the upper structure in the upper region is continued, and the earthwork backfilling of the suspended area is performed through the construction opening reserved on the second floor slab;

[0014] S3: after the earthwork backfilling of the suspended area is completed, the construction of the upper structure in the upper region is continued, and the backfilling soil in the suspended area is drained;

[0015] S4: the construction of the upper structure in the upper region is continued, and the gap between the backfilling soil layer in the suspended area and the second floor slab and the dewatering well are backfilled with earthwork until the suspended area is filled with earth;

[0016] S5: the construction of the upper structure in the upper region is continued, and the construction opening is closed.

[0017] Optionally, in the method for synchronously constructing the high and low parts of the stepped underground structure, S12 further comprises the following steps:

[0018] A water stop steel plate and a steel mesh are reserved on the structure side of the construction opening.

[0019] Optionally, in the method for synchronously constructing the high and low parts of the stepped underground structure, S13, the waterproofing process of the interior of the suspended area comprises the following steps:

[0020] Waterproofing construction is performed on the outer walls 4;

[0021] Waterproofing construction is performed on the bottom plate of the second floor slab.

[0022] Optionally, in the method for simultaneous construction of high and low parts of a stepped underground structure, in S2, the soil backfilling of the air-void area through the reserved construction opening in the second floor slab comprises the following steps:

[0023] The water ramming method is used to backfill the soil of the air-void area.

[0024] Optionally, in the method for simultaneous construction of high and low parts of a stepped underground structure, in S4,

[0025] The coarse sand is used to backfill the soil of the dewatering well.

[0026] Optionally, in the method for simultaneous construction of high and low parts of a stepped underground structure, in S4,

[0027] The micro-expansion and high-fluidity lightweight concrete is used to backfill the gap between the backfill soil layer and the second floor slab in the air-void area.

[0028] Optionally, in the method for simultaneous construction of high and low parts of a stepped underground structure, in S5, the process of plugging construction of the reserved construction opening comprises the following steps:

[0029] The bottom construction cushion of the reserved construction opening;

[0030] After the maintenance of the cushion is completed, the waterproof layer and the reserved water-swelling waterstop are constructed;

[0031] The concrete is poured on the waterproof layer, so that the plugged reserved construction opening is flush with the surface of the second floor slab.

[0032] In the method for simultaneous construction of high and low parts of a stepped underground structure provided by the application, through the use of the temporary formwork support frame to support the formwork of the first floor slab and the formwork of the second floor slab during the construction stages of the first floor slab of the non-air-void area of the underground structure and the second floor slab of the air-void area, the underlying area of the pile cap and the structures (horizontal and vertical structures) in the adjacent basement area are integrally poured at the same time, without the need to wait for the completion of the soil backfilling of the underlying area of the pile cap before the integral horizontal structure construction is performed (i.e., the construction of the underlying area of the pile cap is synchronized with the progress of the adjacent basement structure, without disconnection), which maximizes the saving of the construction period and saves a total of 21 days.

[0033] In addition, the method of the application can ensure that the underground structure is sequentially performed according to the process of cushion → raft 7 → underground structure → upper structure, fully utilizes the construction time of the processes such as strength maintenance of the board wall concrete, waterproofing of the outer wall 4, soil backfilling and waterproof construction, so that these processes do not occupy the key line, can effectively speed up the construction speed, and is suitable for projects with tight construction period or basement with low pile cap, and air-void high floor slab structure that needs to be quickly formed. BRIEF DESCRIPTION OF DRAWINGS

[0034] The above and other objects, features and advantages of the present disclosure will become more apparent from the following detailed description when taken in conjunction with the accompanying drawings, in which like reference characters refer to like parts throughout the figures, and in which:

[0035] Figure 1 is a method flow chart of the method for synchronous construction of high and low parts of a stepped underground structure in an embodiment of the present application;

[0036] Figure 2 is a vertical plane schematic diagram of high and low parts of a stepped underground structure;

[0037] Figure 3 is a plan schematic diagram of a reserved construction opening on a second floor slab in an embodiment of the present application;

[0038] Figure 4 is a vertical plane schematic diagram after step S2 is performed in the method for synchronous construction of high and low parts of a stepped underground structure in an embodiment of the present application;

[0039] Figure 5 is a vertical plane schematic diagram after step S3 is performed in the method for synchronous construction of high and low parts of a stepped underground structure in an embodiment of the present application;

[0040] Figure 6 is a vertical plane schematic diagram after step S4 is performed in the method for synchronous construction of high and low parts of a stepped underground structure in an embodiment of the present application;

[0041] Figure 7 is a vertical plane schematic diagram after the reserved construction opening is constructed by plugging in an embodiment of the present application.

[0042] In the drawings:

[0043] 4 - outer wall; 5 - column; 6 - pile cap; 7 - raft; 8 - first floor slab; 9 - second floor slab; 10 - cushion layer; 11 - soil layer at the bottom of the foundation; D1 - upper area; D2 - non-void area; D3 - void area; H12 - construction opening; H13 - backfill soil; H14 - height of backfill soil before dewatering; H15 - height of backfill soil after dewatering; H16 - dewatering well; H17 - gap filling; H18 - well point filling; H19 - water stop steel plate; H20 - steel mesh; H21 - waterproof layer; H22 - cushion layer; H23 - side edge of the structure; H24 - water-swelling water stop strip. DETAILED DESCRIPTION

[0044] The method for synchronous construction of high and low parts of stepped underground structure will be described in further detail below in conjunction with the accompanying drawings and specific embodiments. The advantages and features of the present application will be more apparent from the following description and claims. It should be noted that the drawings are very simplified and all use non-precise proportions, only for the purpose of facilitating and clarifying the description of the embodiments of the present application.

[0045] The present application will now be described in further detail in conjunction with the accompanying drawings. These drawings are all simplified schematic diagrams, only to schematically illustrate the basic structure of the present application, and therefore only show the components related to the present application.

[0046] In the description of the application, it should be understood that the terms "center", "longitudinal", "transverse", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", and the like indicate the orientation or positional relationship based on the orientation or positional relationship shown in the drawings, only for the purpose of facilitating the description of the application and simplifying the description, and therefore cannot be understood as indicating or implying that the devices or elements referred to must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as limiting the application.

[0047] In addition, the terms "first" and "second" are only for descriptive purposes and cannot be understood as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Therefore, the features defined with "first" and "second" can explicitly or implicitly include one or more of the features. In the description of the application, the meaning of "multiple" is two or more, unless otherwise specifically limited.

[0048] In the application, unless otherwise specifically defined and limited, the terms "mounting", "connection", "connection", "fixing" and the like should be broadly understood, for example, it can be fixedly connected, or it can be detachably connected, or it can be integrally connected; it can be mechanically connected, or it can be electrically connected; it can be directly connected, or it can be indirectly connected through an intermediate medium; it can be the communication inside two elements. For those skilled in the art, the specific meaning of the above terms in the application can be understood according to the specific circumstances.

[0049] Please refer to Figures 1 to 7 The method for synchronous construction of high and low parts of stepped underground structure comprises the following steps:

[0050] First, perform step S1, according to the construction scheme, excavate the basement foundation pit to the soil layer 11 at the bottom of the foundation, and then sequentially perform raft 10, raft 7 and pile cap 6 construction, underground structure construction on the soil layer at the bottom of the foundation; wherein, the underground structure construction comprises:

[0051] S11: synchronously constructing the columns 5 and the outer wall 4 in the non-suspended area D2 and the suspended area D3;

[0052] S12: synchronously constructing the first floor 8 in the non-suspended area D2 (i.e. the basement n+1 floor area) and the second floor 9 in the suspended area; wherein, during the construction of the first floor 8 and the second floor 9, a temporary formwork support frame is needed to be set at the bottom of the formwork of the first floor 8 and the formwork of the second floor 9; as shown in Figure 3 the reserved construction hole H12 on the second floor 9, a plurality of construction holes H12 are arranged on the second floor 9 at predetermined intervals, if there is one more structural beam between the construction holes, an additional construction hole needs to be added between the two structural beams; in order to improve the waterproofness and firmness of the structure after the hole H12 is blocked, the following steps are further included: reserving a water stop steel plate H19 and a steel mesh H20 on the structural side H23 of the construction hole.

[0053] S13: after the structure in the non-suspended area D2 and the suspended area D3 is cured to the design strength, the temporary formwork support frame at the bottom of the formwork of the first floor 8 and the formwork of the second floor 9 is removed, the interior of the suspended area is waterproofed, and the upper structure in the upper area D1 (i.e. the basement n floor area) of the non-suspended area and the suspended area is synchronously constructed; wherein, the process of waterproofing the interior of the suspended area includes the following steps: waterproofing the outer wall 4; waterproofing the bottom plate of the second floor.

[0054] Next, please refer to Figure 4 , execute step S2, after the waterproofing in the interior of the suspended area D3 is completed, continue the construction of the upper structure of the upper area D1, and backfill the earthwork of the suspended area D3 through the reserved construction hole H12 on the second floor 9; in this embodiment, the water ramming method is preferably used to backfill the earthwork of the suspended area. It can be understood that the water ramming method is not limited here, and other earth backfilling methods can also be used.

[0055] Next, please refer to Figure 5 , execute step S3, after the earthwork backfilling of the suspended area D3 is completed, continue the construction of the upper structure of the upper area D1, and drain the backfill soil H13 in the suspended area D3; at this time, the height line of the backfill soil layer in D3 falls from the pre-dewatering backfill height H14 to the post-dewatering backfill height H15.

[0056] Next, please refer to Figure 6, execute step S4, continue the construction of the upper structure of the upper area D1, at the same time, backfill the gap between the backfill soil layer and the second floor 9 in the overhead area D3 (the gap corresponds to the gap filled with H17 after the backfill soil), and backfill the dewatering well H16 (the well point filling H18 is formed after the backfill soil of the dewatering well H16), until the overhead area is filled with soil; preferably, the dewatering well is backfilled with coarse sand; the gap between the backfill soil layer and the second floor in the overhead area is backfilled with micro-expansion, high-fluidity lightweight concrete.

[0057] Then, execute step S5, continue the construction of the upper structure of the upper area D1, at the same time, carry out the plugging construction of the reserved construction opening H12.

[0058] Specifically, the process of plugging construction of the reserved construction opening includes the following steps:

[0059] S51: bottom construction cushion H22 of the reserved construction opening H12;

[0060] S52: after the maintenance of the cushion H22 is completed, the waterproof layer H21 and the water-swelling waterstop H24 are constructed;

[0061] S53: concrete pouring is carried out on the waterproof layer H21, so that the plugged reserved construction opening H12 is flush with the surface of the second floor 9.

[0062] By using the temporary formwork support frame to support the formwork of the first floor and the formwork of the second floor during the construction stage of the first floor of the non-overhead area of the underground structure and the second floor of the overhead area, the underlying area of the pile cap and the structure (horizontal and vertical structure) in the adjacent basement area are poured at the same time, without the need to wait for the underlying area of the pile cap to be backfilled before the overall horizontal structure is constructed (i.e. the construction of the underlying area of the pile cap is synchronized with the progress of the adjacent basement structure, and there is no disconnection), which maximizes the saving of construction period, at least saving a total of 21 days.

[0063] In addition, the method of the present application can ensure that the underground structure is carried out in the order of cushion → raft → underground structure → upper structure, etc., fully utilizing the construction time of processes such as concrete strength maintenance of panel wall, waterproofing of external wall, earth backfilling and waterproofing construction, so that these processes do not occupy the critical route, effectively speeding up the construction speed, and being suitable for projects with tight construction period or basement with low pile cap, overhead high floor structure requiring rapid formation.

[0064] In order to better understand the advantages of the method of the present application in construction period compared with the traditional construction method, please refer to the following horizontal comparison table of the traditional construction method and the construction method of the present application, as follows:

[0065]

[0066] Based on the method, the construction of the high and low parts of the stepped underground structure can save 14 days of concrete curing, 1 day of form removal and cleaning, 12 days of earthwork backfilling and layering compaction, 2 days of base mat and waterproof construction, and at least 21 days of total construction period.

[0067] It should be noted that, for the foregoing method embodiments, in order to simply describe, they are all expressed as a series of action combinations, but those skilled in the art should know that the present application is not limited by the action sequence described, because according to the present application, certain steps can be performed in other sequences or simultaneously. Secondly, those skilled in the art should know that the embodiments described in the specification all belong to preferred embodiments, and the actions and modules involved are not necessarily necessary for the present application.

[0068] The above description is only a description of the preferred embodiments of the present application, and does not limit the scope of the present application in any way, and any modification or modification made by those skilled in the art according to the above disclosure is within the protection scope of the claims.

Claims

1. A method for simultaneous construction of high and low portions of a stepped underground structure, characterized in that, It comprises the following steps: S1: according to the construction scheme, after the basement foundation pit is excavated to the soil layer (11) at the bottom of the foundation, the cushion (10), the pile cap (6) construction, the raft (7) and the underground structure construction are sequentially carried out on the soil layer (11) at the bottom of the foundation; wherein, the underground structure construction comprises: S11: synchronously constructing the columns (5) and the outer wall (4) of the non-suspended area (D2) and the suspended area (D3); S12: synchronously constructing the first floor (8) of the non-suspended area (D2) and the second floor (9) of the suspended area (D3); wherein, during the construction of the first floor (8) and the second floor (9), a temporary formwork support frame needs to be erected at the bottom of the formwork of the first floor (8) and the formwork of the second floor (9); a construction opening (H12) is reserved on the second floor (9); S13: after the structure maintenance in the non-suspended area (D2) and the suspended area (D3) reaches the design strength, the temporary formwork support frame at the bottom of the formwork of the first floor (8) and the formwork of the second floor (9) is removed, waterproofing is done inside the suspended area (D3), and the upper structure of the upper area (D1) located in the non-suspended area (D2) and the suspended area (D3) is synchronously constructed; S2: after the waterproofing inside the suspended area (D3) is completed, the soil backfilling of the suspended area (D3) is carried out through the construction opening (H12) reserved on the second floor (9) while the construction of the upper structure of the upper area (D1) continues; S3: after the soil backfilling of the suspended area (D3) is completed, the backfilling soil (H13) in the suspended area (D3) is drained while the construction of the upper structure of the upper area (D1) continues; S4: the soil backfilling of the gap between the backfilling soil layer in the suspended area (D3) and the second floor (9) and the dewatering well (H16) is carried out while the construction of the upper structure of the upper area (D1) continues, until the suspended area (D3) is filled with soil; S5: the construction opening (H12) is closed while the construction of the upper structure of the upper area (D1) continues.

2. The method for simultaneous construction of high and low portions of a stepped underground structure according to claim 1, wherein In S12, the following steps are further included: Water stop steel plates (H19) and steel mesh sheets (H20) are reserved on the structure side (H23) of the construction opening (H12).

3. The method for simultaneous construction of high and low portions of a stepped underground structure according to claim 1, wherein In S13, the waterproofing process of the inside of the suspended area (D3) comprises the following steps: Waterproofing construction is carried out on the outer wall (4); Waterproofing construction is carried out on the bottom plate of the second floor (9).

4. The method for simultaneous construction of high and low portions of a stepped underground structure according to Claim 1, wherein In S2, the soil backfilling of the suspended area (D3) through the construction opening (H12) reserved on the second floor (9) comprises the following steps: Water ramming method is used to backfill the soil of the suspended area (D3).

5. The method for simultaneous construction of high and low parts of a stepped underground structure according to claim 4, characterized in that, In S4, Coarse sand is used to backfill the soil of the dewatering well (H16).

6. The method for simultaneous construction of high and low parts of a stepped underground structure according to claim 4, characterized in that, In S4, Micro-expansion, high-fluidity lightweight concrete is used to backfill the gap between the backfilling soil layer in the suspended area (D3) and the second floor (9).

7. The method for simultaneous construction of high and low parts of a stepped underground structure according to any one of claims 1 to 6, characterized in that, In S5, the process of closing the construction opening (H12) comprises the following steps: A construction cushion (H22) is constructed at the bottom of the construction opening (H12); After the maintenance of the cushion layer (H22) is completed, the waterproof layer (H21) and the water-swelling sealing strip (H24) are constructed; The concrete is poured on the waterproof layer (H21) so that the blocked reserved construction hole (H12) is flush with the surface of the second floor (9).

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