Foundation pit excavation method and device

Abstract

The invention discloses a foundation pit excavation method and device, and belongs to the technical field of foundation pit construction.The foundation pit excavation method comprises the steps that the soil layer number of a current to-be-excavated layer is determined, a soil layer top area corresponding to the soil layer number is determined, a supporting structure is poured to the soil layer top area, and the to-be-excavated layer is excavated; when excavation reaches a specified depth value, whether the soil layer number reaches a preset layer number or not is judged, and if yes, excavation of the foundation pit is completed; otherwise, the next soil layer number corresponding to the soil layer number is determined, and the to-be-excavated layer corresponding to the next soil layer number is subjected to supporting structure pouring and excavation. The foundation pit excavation device is applied to the foundation pit excavation method and comprises the tower crane and the stand column pile. Through the method of staggered-layer excavation and segmented pouring of the supporting structure, the excavation depth and progress of the foundation pit can be accurately controlled, the construction efficiency is improved, the risk of upheaval deformation of the foundation pit is reduced, and the quality of the foundation pit is guaranteed.

Description

Technical Field

[0001] The invention relates to the technical field of foundation pit construction, and in particular to a foundation pit excavation method and device. Background Art

[0002] With the continuous acceleration of urbanization and the development and utilization of underground space, more and more deep and large foundation pit excavation projects are being carried out in the construction of various large-scale infrastructure projects.

[0003] At present, deep and large foundation pit excavation mainly adopts two methods: partial excavation and overall excavation. The partial excavation method has disadvantages in terms of investment, construction period, and later processing of partition walls. The partial pits have the characteristics of high interference risk, complex process connection, more supports, and long construction period, which directly affect the safety and construction period of foundation pit implementation; while overall excavation has the advantages of short construction period and simple construction, but this method is not conducive to controlling the uplift deformation of the foundation pit, and has an adverse effect on the safety of the internal structure. In actual projects, the uplift deformation of the foundation pit may cause structural damage, affecting the quality and safety of the project. Summary of the invention

[0004] The object of the present invention is to provide a foundation pit excavation method and device to solve the technical problems existing in the prior art of low efficiency of the sub-pit excavation method and poor quality of the overall excavation method.

[0005] As conceived above, the technical solution adopted by the present invention is:

[0006] In one aspect, the present invention provides a foundation pit excavation method, comprising:

[0007] Determine the soil layer number of the current layer to be excavated, determine the top area of ​​the soil layer corresponding to the soil layer number, cast a supporting structure on the top area of ​​the soil layer, and excavate the layer to be excavated;

[0008] When the excavation reaches the specified depth value, it is determined whether the soil layer number reaches the preset layer number, and if so, the excavation of the foundation pit is completed;

[0009] Otherwise, the next soil layer number corresponding to the soil layer number is determined, and the supporting structure is cast and excavation is performed on the to-be-excavated layer corresponding to the next soil layer number.

[0010] Preferably, after the support structure is cast, the strength of the support structure is detected, and when the strength of the support structure reaches a preset strength, excavation is performed based on a preset foundation pit position.

[0011] Preferably, when excavating the layer to be excavated corresponding to the soil layer number, the layer to be excavated corresponding to each soil layer number above the soil layer number is excavated in the horizontal direction.

[0012] Preferably, when the excavation reaches a specified length in the horizontal direction, the supporting structure is cast for the to-be-excavated layer corresponding to each soil layer number above, and it is determined whether the specified length reaches a preset length. If so, the excavation of the foundation pit is completed;

[0013] Otherwise, when the strength of the supporting structure reaches a preset strength, excavation continues in the horizontal direction.

[0014] Preferably, if the soil layer number reaches the preset layer number, the bottom plate is poured in the to-be-excavated layer corresponding to the soil layer number.

[0015] Preferably, the base plate is connected to a plurality of column piles.

[0016] Preferably, the support structure is connected to upper lattice columns of a plurality of column piles.

[0017] Preferably, the support structure is maintained at specified time intervals.

[0018] Preferably, an earth embankment is formed between two adjacent layers to be excavated.

[0019] On the other hand, the present invention further provides a foundation pit excavation device, which is applied to the above foundation pit excavation method, comprising:

[0020] A tower crane, used for lifting the supporting structure and the soil in the foundation pit;

[0021] The column piles are used to carry the supporting structure.

[0022] Beneficial effects of the present invention:

[0023] The foundation pit excavation method proposed in the present invention divides the foundation pit into multiple layers to be excavated and performs staggered excavation according to the soil layer number. On the one hand, the whole pit can be excavated in a sequential manner, which reduces the construction period and construction difficulty. On the other hand, due to the staggered excavation and the early formation of the bottom plate, the stress and deformation of the soil are more uniform, which reduces the amplitude of the foundation pit uplift and the settlement of the surrounding soil. And the support structure is cast in sections for each soil layer number to ensure the stability of the soil in the foundation pit excavation area. In summary, staggered excavation and segmented casting of the support structure are conducive to accurately controlling the excavation depth and progress of the foundation pit, improving construction efficiency, reducing the risk of foundation pit uplift and deformation, and ensuring the quality of the foundation pit. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 is a first schematic diagram of a foundation pit excavation method provided in Embodiment 1 of the present invention;

[0025] Figure 2 is a second schematic diagram of the foundation pit excavation method provided in the first embodiment of the present invention;

[0026] Figure 3is a third schematic diagram of the foundation pit excavation method provided in the first embodiment of the present invention;

[0027] Figure 4 It is the fourth schematic diagram of the foundation pit excavation method provided in the first embodiment of the present invention.

[0028] In the figure:

[0029] 100, layer to be excavated;

[0030] 1. Column piles; 2. Base plate; 3. Support structure; 4. Tower crane; 5. Tower crane piles. DETAILED DESCRIPTION

[0031] Embodiments of the present invention are described in detail below, examples of which are shown in the accompanying drawings, wherein the same or similar reference numerals throughout represent the same or similar elements or elements having the same or similar functions. The embodiments described below with reference to the accompanying drawings are exemplary and are intended to be used to explain the present invention, and should not be construed as limiting the present invention.

[0032] In the description of the present invention, unless otherwise clearly specified and limited, the terms "connected", "connected", and "fixed" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0033] In the present invention, unless otherwise clearly specified and limited, a first feature being "above" or "below" a second feature may include that the first and second features are in direct contact, or may include that the first and second features are not in direct contact but are in contact through another feature between them. Moreover, a first feature being "above", "above" and "above" a second feature includes that the first feature is directly above and obliquely above the second feature, or simply indicates that the first feature is higher in level than the second feature. A first feature being "below", "below" and "below" a second feature includes that the first feature is directly below and obliquely below the second feature, or simply indicates that the first feature is lower in level than the second feature.

[0034] The technical solution of the present invention is further described below with reference to the accompanying drawings and through specific implementation methods.

[0035] Embodiment 1

[0036] See also Figures 1 to 4The foundation pit excavation method provided by the embodiment of the present invention includes determining the soil layer number of the current layer to be excavated 100, and determining the top area of ​​the soil layer corresponding to the soil layer number, casting the supporting structure 3 on the top area of ​​the soil layer, and excavating the layer to be excavated 100; when excavating to a specified depth value, judging whether the soil layer number reaches a preset layer number, if so, completing the excavation of the foundation pit; otherwise, determining the next soil layer number corresponding to the soil layer number, casting the supporting structure 3 and excavating the layer to be excavated 100 corresponding to the next soil layer number.

[0037] The foundation pit excavation method proposed in the present invention divides the foundation pit into multiple layers 100 to be excavated, and performs staggered excavation according to the soil layer number. On the one hand, the whole pit can be excavated in a sequential manner, which reduces the construction period and the construction difficulty; on the other hand, due to the staggered excavation and the early formation of the bottom plate, the stress and deformation of the soil are more uniform, which reduces the amplitude of the foundation pit uplift and the settlement of the surrounding soil. And for each soil layer number, the support structure 3 is cast in sections to ensure the stability of the soil in the foundation pit excavation area. In summary, staggered excavation and segmented casting of the support structure 3 are conducive to accurately controlling the excavation depth and progress of the foundation pit, improving construction efficiency, reducing the risk of foundation pit uplift and deformation, and ensuring the quality of the foundation pit.

[0038] The preset layer number may be the soil layer number of any layer 100 to be excavated in the foundation pit, or the soil layer number of the bottom layer 100 to be excavated in the foundation pit, which is determined according to actual needs and is not limited here.

[0039] The specific steps of foundation pit excavation method are explained below.

[0040] First, after determining the top area of ​​the soil layer corresponding to the soil layer number, it is necessary to cast the supporting structure 3 on the top area of ​​the soil layer. Specifically, reinforced concrete is used as the main material of the supporting structure 3. First, according to the design requirements of the foundation pit and the characteristics of the soil layer, the size and shape of the supporting structure 3 are determined. Before construction, prepare the required steel materials, tie and weld the steel bars according to the design requirements, and form a solid steel skeleton. At the same time, build a formwork at the construction site to ensure that the flatness and verticality of the formwork meet the requirements to ensure that the shape of the supporting structure 3 after pouring is regular. During the pouring process, the layered pouring method is adopted, and the pouring thickness of each layer is controlled at about 30 cm. Use a vibrating rod to fully vibrate to ensure that the concrete is dense and avoid quality problems such as honeycomb surface.

[0041] After the pouring of the supporting structure 3 is completed, the strength of the supporting structure 3 is tested. When the strength of the supporting structure 3 reaches the preset strength, excavation is performed based on the preset foundation pit position. Ensuring that the supporting structure 3 reaches sufficient bearing capacity provides reliable safety guarantees for subsequent excavation work, avoids safety accidents such as foundation pit collapse caused by insufficient strength of the supporting structure 3, and enhances the stability and safety of the construction process. The strength testing method of the supporting structure 3 can adopt the rebound method or the core sampling method, both of which are common processing methods in the field, and the specific process will not be repeated here.

[0042] In addition, the support structure 3 is maintained at specified intervals to prevent cracks in the concrete, thereby ensuring that the support structure 3 reaches the strength and durability required by the design, and providing reliable protection for the stability of the foundation pit. The maintenance process can be carried out by covering the support structure 3 with plastic film and straw mats for moisture maintenance, which is not limited here.

[0043] Specifically, the support structure 3 is connected to the upper lattice columns of the plurality of column piles 1. The stability and bearing capacity of the entire support system can be enhanced. The column piles 1 can provide additional vertical support for the support structure 3, effectively share the horizontal load, thereby improving the safety of the foundation pit during excavation and reducing the risk of collapse and deformation.

[0044] When the strength of the supporting structure 3 reaches the preset strength, excavation is performed based on the preset foundation pit position. The excavation process uses equipment such as excavators, using a basin excavation method, first excavating the middle part and then gradually advancing to the surrounding areas.

[0045] Specifically, when excavating the to-be-excavated layer 100 corresponding to the soil layer number, excavate the to-be-excavated layer 100 corresponding to each soil layer number above the soil layer number in the horizontal direction. This method can provide a certain support for the soil around the foundation pit. The excavation of the middle part can release part of the soil pressure. At the same time, the unexcavated soil around the pit can effectively resist the deformation of the pit wall, thereby enhancing the overall stability of the foundation pit and reducing the risk of collapse. Secondly, the excavation sequence that gradually advances to the surrounding areas helps to control the displacement of the soil during the excavation process. In addition, the excavation of the entire pit is realized in a sequential manner, which reduces the construction period and the difficulty of construction.

[0046] More specifically, when excavating to the specified length in the horizontal direction, the supporting structure 3 is cast for the to-be-excavated layer 100 corresponding to each soil layer number above, which can provide effective support for the excavated part in time, enhance the stability of the foundation pit wall, and reduce the risk of landslides. And judge whether the specified length reaches the preset length. If so, complete the excavation of the foundation pit; by judging whether the specified length reaches the preset length, the progress and scope of the excavation can be accurately controlled to avoid excessive excavation or insufficient excavation, thereby improving the accuracy and quality of the construction. When the specified length does not reach the preset length, excavation in the horizontal direction will continue only after the strength of the supporting structure 3 reaches the preset strength, ensuring that the supporting structure 3 has sufficient bearing capacity to cope with subsequent excavation operations. An earth embankment is formed between two adjacent layers to be excavated, thereby further ensuring the stability and safety of the foundation pit.

[0047] It is understandable that the specified length and the preset length need to be adaptively adjusted according to the actual working conditions on site and are not limited here.

[0048] When excavation reaches the specified depth value, the soil layer number is determined. If the soil layer number reaches the preset layer number, the bottom plate 2 is cast in the to-be-excavated layer 100 corresponding to the soil layer number. The bottom plate 2 can provide a stable support for the bottom of the foundation pit in time, which helps to enhance the overall stability of the foundation pit, prevent uneven settlement or uplift at the bottom of the pit, and ensure the safety of the foundation pit structure. Secondly, the timely casting of the bottom plate 2 can effectively block the infiltration of groundwater, reduce the erosion of groundwater on the bottom of the foundation pit, and reduce the construction risks and quality problems caused by water damage.

[0049] Specifically, the bottom plate 2 is connected to a plurality of column piles 1. During the excavation of the foundation pit, the soil at the bottom of the pit tends to rebound upward, and the pull-out resistance of the column piles 1 can effectively suppress this rebound, thereby reducing the degree of uplift and deformation of the bottom of the foundation pit.

[0050] It is understandable that the foundation pit excavation method of the present invention does not have to be adopted from the topmost layer to be excavated 100 of the foundation pit, and the method can be adopted from a certain layer to be excavated 100 inside the foundation pit, and the soil above the layer to be excavated 100 can be excavated by conventional methods, which is not limited here. In addition, the method can select multiple locations in a single foundation pit for synchronous excavation.

[0051] For the convenience of description and explanation, the following is an example of a foundation pit that only needs to excavate two layers of the to-be-excavated layer 100, and it is assumed that the foundation pit has only one excavation position. The construction process and steps are as follows:

[0052] It is defined herein that the layer to be excavated 100 is divided into a first layer and a second layer along the height direction from top to bottom.

[0053] First, the support structure 3 of the top area of ​​the entire soil layer is cast and constructed; after the support structure 3 of the top area of ​​the soil layer reaches a preset strength, a basin-like excavation of a local area of ​​the first layer to be excavated 100 is performed based on the preset foundation pit position; after the excavation is completed, the support structure 3 is cast in the excavated area, and the support structure 3 should be connected to the upper lattice columns of the plurality of column piles 1, and at the same time, the basin-like excavation of the first layer to be excavated 100 is continued to the surrounding areas along the excavated area;

[0054] After the supporting structure 3 poured in the previous step reaches the required strength, a basin-shaped excavation is performed in a local area of ​​the second layer to be excavated 100 within the scope of the supporting structure 3, and at the same time, the basin-shaped excavation of the first layer to be excavated 100 is continued around the excavated area, and the supporting structure 3 of the excavated area is poured;

[0055] After excavation to the bottom of the pit, cast the bottom plate 2 in the excavated area, the bottom plate 2 should be connected to multiple column piles 1, and at the same time continue to excavate the first layer 100 and the second layer 100 in a basin-like manner around the excavated area, and cast the supporting structure 3 of the excavated area; until the excavation of the entire foundation pit is completed.

[0056] It is understandable that the excavation method of the foundation pit for three-layer, four-layer or other multi-layer to-be-excavated layers 100 is the same as the above principle and will not be elaborated here.

[0057] Embodiment 2

[0058] The embodiment of the present invention also provides a foundation pit excavation device, which is applied to the above-mentioned foundation pit excavation method, including a tower crane 4 and column piles 1. Among them, the tower crane 4 is used to lift the supporting structure 3 and the soil in the foundation pit; it improves the efficiency of material transportation and earthwork cleaning, and reduces the labor intensity and time cost of manual handling. Its precise lifting operation helps to ensure that the supporting structure 3 is accurately positioned and improves the accuracy and quality of construction. Secondly, the column piles 1 are used to bear the supporting structure 3, providing stable vertical support for the supporting structure 3. It can effectively share the load borne by the supporting structure 3, enhance the stability and safety of the entire foundation pit support system, and reduce the risk of foundation pit collapse and foundation pit uplift deformation.

[0059] Specifically, a tower crane pile 5 is provided at the bottom of the tower crane 4, which increases the contact area and support points between the tower crane 4 and the ground, effectively disperses the load borne by the tower crane 4, reduces the possibility of tilting or shaking of the tower crane 4 when lifting heavy objects, and improves safety during the construction process.

[0060] The above embodiments are only to illustrate the basic principles and characteristics of the present invention. The present invention is not limited by the above embodiments. Without departing from the spirit and scope of the present invention, the present invention may be subject to various changes and modifications, which are within the scope of the present invention. The scope of protection of the present invention is defined by the attached claims and their equivalents.

Claims

1. A foundation pit excavation method, wherein the foundation pit is divided into multiple layers (100) to be excavated along the height direction, and each layer (100) to be excavated has a soil layer number, characterized in that: include: Determining the soil layer number of the current layer to be excavated (100), and determining the top area of ​​the soil layer corresponding to the soil layer number, casting a support structure (3) on the top area of ​​the soil layer, and excavating the layer to be excavated (100); When the excavation reaches the specified depth value, it is determined whether the soil layer number reaches the preset layer number, and if so, the excavation of the foundation pit is completed; Otherwise, the next soil layer number corresponding to the soil layer number is determined, and the supporting structure (3) and excavation are performed on the to-be-excavated layer (100) corresponding to the next soil layer number.

2. The foundation pit excavation method according to claim 1, characterized in that: After the pouring of the support structure (3) is completed, the strength of the support structure (3) is detected, and when the strength of the support structure (3) reaches a preset strength, excavation is performed based on a preset foundation pit position.

3. The foundation pit excavation method according to claim 1, characterized in that: When excavating the to-be-excavated layer (100) corresponding to the soil layer number, the to-be-excavated layer (100) corresponding to each soil layer number above the soil layer number is excavated in the horizontal direction.

4. The foundation pit excavation method according to claim 3, characterized in that: When the excavation reaches the specified length in the horizontal direction, the support structure (3) is poured on the to-be-excavated layer (100) corresponding to each soil layer number above, and it is determined whether the specified length reaches the preset length. If so, the excavation of the foundation pit is completed; Otherwise, when the strength of the supporting structure (3) reaches a preset strength, excavation continues in the horizontal direction.

5. The foundation pit excavation method according to claim 1, characterized in that: If the soil layer number reaches the preset layer number, a bottom plate (2) is cast in the to-be-excavated layer (100) corresponding to the soil layer number.

6. The foundation pit excavation method according to claim 5, characterized in that: The base plate (2) is connected to a plurality of column piles (1).

7. The foundation pit excavation method according to claim 1, characterized in that: The supporting structure (3) is connected to the upper lattice columns of a plurality of column piles (1).

8. The foundation pit excavation method according to any one of claims 1 to 7, characterized in that: The support structure (3) is maintained at specified time intervals.

9. The foundation pit excavation method according to any one of claims 1 to 7, characterized in that: An earth embankment is formed between two adjacent layers (100) to be excavated.

10. A foundation pit excavation device, characterized in that: The foundation pit excavation method applied to any one of claims 1 to 9 comprises: A tower crane (4) for lifting the supporting structure (3) and the soil in the foundation pit; The column pile (1) is used to support the supporting structure (3).

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