Deep and large foundation pit structure and construction method thereof

Abstract

The present application relates to the technical field of building engineering, and particularly relates to a deep and large foundation pit structure and a construction method thereof, the deep and large foundation pit structure comprising a pit body and a plurality of lateral support members, the inner circumferential wall of the pit body being provided with a first enclosure structure, the middle part of the pit body being provided with a core island, the outer circumferential wall of the core island being provided with a second enclosure structure; each lateral support member is arranged at intervals around the outer circumferential side of the central core island, the first end of each lateral support member is fixedly connected to the side of the second enclosure structure away from the core island, and the second end of each lateral support member is fixedly connected to the side of the first enclosure structure away from the inner circumferential wall of the pit body; the core island is located above the soil uplift prediction position of the bottom of the pit body, and is helpful to control the soil uplift at the bottom of the pit body under the gravity action of the core island; in addition, the setting of the core island can shorten the length of the lateral support member, and reduce the influence of the soil uplift on the stability of the internal support structure; therefore, the deep and large foundation pit structure can improve the stability of the internal support structure.

Description

Technical Field

[0001] The present invention relates to the technical field of construction engineering, and in particular to a deep foundation pit structure and a construction method thereof. Background Art

[0002] As my country's economy shifts from high-speed growth to high-quality development, urban construction has also shifted from incremental expansion to tapping the potential of existing stock. As an important means to break through the bottleneck of urban development in the "stock era" and ensure land supply, old city renovation has become the main theme of major urban development during the "14th Five-Year Plan" period. The construction environment involved in old city renovation is generally more complex, and it mainly faces the following problems: the old city renovation area generally has a large development area and is mostly located in areas with busy urban traffic and complex surrounding environment. In order to avoid the impact of deep and large foundation pits on the surrounding soil, the internal support structure of the deep and large foundation pits needs to be equipped with a large number of transverse supports arranged along the diameter of the foundation pit. The total length of the transverse supports is long, resulting in poor stability of the internal support structure. In addition, the soil at the bottom of the deep and large foundation pits is prone to uplift. The uplift of the soil at the bottom of the deep and large foundation pits causes changes in the stress conditions of the internal support structure, which will also have an adverse effect on the stability of the internal support structure. Summary of the Invention

[0003] The technical problem to be solved by the present invention is that the stability of the internal support structure of the existing deep and large foundation pit is poor due to the influence of the length of the support beam and the uplift of the soil at the bottom of the foundation pit.

[0004] In order to solve the above technical problems, the purpose of the present invention is to provide a deep and large foundation pit structure, including a pit body and a plurality of transverse support members, the inner peripheral wall of the pit body is provided with a first retaining structure, the middle part of the pit body is provided with a core island, and the core island is located above the predicted position of the soil uplift at the bottom of the pit body, and the outer peripheral wall of the core island is provided with a second retaining structure; each of the transverse support members is arranged at intervals around the outer peripheral side of the core island, the first end of each of the transverse support members is fixedly connected to the side of the second retaining structure away from the core island, and the second end of each of the transverse support members is fixedly connected to the side of the first retaining structure away from the inner peripheral wall of the pit body.

[0005] As a preferred solution, the upper end of at least one of the transverse supports is provided with a trestle for transporting construction equipment from the outside of the pit body to the upper end of the core island.

[0006] As a preferred solution, a retention island is provided in the pit for preserving ancient trees or undemolished buildings. The retention island is spaced apart from the inner wall of the pit and the core island, and a third enclosure structure is provided on the outer wall of the retention island.

[0007] As a preferred embodiment, each of the transverse support members includes a transversely arranged support frame, the retention island is arranged in the middle of any one of the support frames, and a transition connection section is provided between the third enclosure structure and the support frame, and the transition connection section is a radial truss structure or a support plate.

[0008] As a preferred embodiment, the deep foundation pit structure includes a first annular beam and a second annular beam, wherein the first annular beam is arranged around the inner side wall of the pit body, and the outer side of the first annular beam is fixedly connected to the side of the first enclosure structure facing away from the inner peripheral wall of the pit body; the second annular beam is arranged around the outer periphery of the core island, and the inner side of the second annular beam is fixedly connected to the side of the second enclosure structure facing away from the core island;

[0009] The first end of each of the transverse support members is fixedly connected to the inner side of the first annular beam, and the second end of each of the transverse support members is fixedly connected to the outer side of the second annular beam.

[0010] As a preferred solution, each of the transverse support members includes a first crossbeam and a plurality of support columns arranged at intervals along the length direction of the corresponding first crossbeam and used to support the corresponding first crossbeam.

[0011] A construction method for the above-mentioned deep and large foundation pit structure comprises the following steps:

[0012] Determining a design area of ​​the core island and positions of each transverse support member based on a design area of ​​the pit body, such that the design area of ​​the core island is located above a predicted position of soil uplift at the bottom of the pit body;

[0013] Constructing a first enclosure structure around the designed area of ​​the pit body, and constructing a second enclosure structure around the designed area of ​​the core island;

[0014] The pit body is excavated layer by layer and each of the horizontal supports is constructed.

[0015] As a preferred solution, the position and structure of each of the transverse supports are determined according to the design area of ​​the core island and the position of each retained island.

[0016] As a preferred solution, “excavating the pit layer by layer and constructing each of the horizontal supports” includes:

[0017] When the pit is excavated to a first set depth, a first ring beam, a second ring beam and a transverse support are constructed;

[0018] Constructing the transverse supports includes:

[0019] Inserting each support column at the bottom of the pit body, wherein the height of each support column is greater than the total designed depth of the pit body;

[0020] A first transverse support frame, a first annular frame arranged around the inner side wall of the pit body, and a second annular frame arranged around the outer periphery of the core island are provided at the upper end of each support column;

[0021] Concrete is poured into the first transverse support frame, the first annular frame, and the second annular frame. The first transverse support frame poured with concrete forms a first transverse beam, the first annular frame poured with concrete forms a first annular beam, and the second annular frame poured with concrete forms a second annular beam.

[0022] As a preferred solution, after the concrete of the first cross beam, the first ring beam and the second ring beam solidifies, the method includes:

[0023] The pit body is excavated downward to a second set depth, a second transverse support frame is fixedly connected to the middle of each support column, a third annular frame is arranged below the first annular beam, and the third annular frame is fixed to the inner side of the pit body; a fourth annular frame is arranged below the second annular beam, and the fourth annular frame is fixed to the outer side of the core island, concrete is integrally poured in the third annular frame, the fourth annular frame and each second transverse support frame, the third annular frame with concrete poured forms a third annular beam, the fourth annular frame with concrete poured forms a fourth annular beam, and the second transverse support frame after concrete pouring forms a second transverse beam.

[0024] Compared with the prior art, the present invention has the following beneficial effects:

[0025] The deep and large foundation pit structure of the present invention includes a pit body and multiple transverse support members, the inner peripheral wall of the pit body is provided with a first retaining structure, the middle part of the pit body is provided with a core island, and the outer peripheral wall of the core island is provided with a second retaining structure; the transverse support members are arranged at intervals around the outer peripheral side of the central core island, the first end of each transverse support member is fixedly connected to the side of the second retaining structure away from the core island, and the second end of each transverse support member is fixedly connected to the side of the inner peripheral wall of the first retaining structure away from the pit body; the core island is located above the predicted position of soil uplift at the bottom of the pit body, and under the action of the gravity of the core island, it helps to control the soil uplift at the bottom of the pit body, thereby reducing the influence of the soil uplift on the stability of the inner support structure; moreover, the provision of the core island can shorten the length of the transverse support members, further improving the stability of the inner support structure; therefore, the deep and large foundation pit structure of the present invention can improve the stability of the inner support structure. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 A top view of the uppermost layer of the deep foundation pit structure of the present invention;

[0027] Figure 2 A top view of the second layer of the deep foundation pit structure of the present invention;

[0028] In the figure, 1, pit body; 11, first enclosure; 2, transverse support; 3, core island; 31, second enclosure; 41, first island body; 42, second island body; 43, third island body; 51, first ring beam; 52, second ring beam; 53, third ring beam; 54, fourth ring beam; 55, second cross beam; 6, building body. DETAILED DESCRIPTION

[0029] The specific embodiments of the present application will be further described in detail below with reference to the accompanying drawings and examples. The following examples are used to illustrate the present application, but are not used to limit the scope of the present application.

[0030] In the description of the present application, it should be understood that the terms "upper", "lower", "left", "right", "top", "bottom", etc. indicate the orientation or positional relationship shown in the drawings, and are only for the convenience of describing the present application and simplifying the description, and do not indicate or imply 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 a limitation on the present application. It should be understood that the terms "first", "second", etc. are used to describe various information in the present application, but these information should not be limited to these terms, and these terms are only used to distinguish the same type of information from each other. For example, the "first" information can also be referred to as "second" information without departing from the scope of the present application, and similarly, the "second" information can also be referred to as "first" information.

[0031] As Figure 1 , Figure 2As shown, the preferred embodiment of the deep and large foundation pit structure of the present application comprises a pit body 1 and a plurality of lateral support members 2, the inner circumferential wall of the pit body 1 is provided with a first enclosure structure 11, the middle part of the pit body 1 is provided with a core island 3, and the core island 3 is located above the predicted position of the soil uplift at the bottom of the pit body 1, and the outer circumferential wall of the core island 3 is provided with a second enclosure structure 31; each of the lateral support members 2 is arranged at intervals around the outer circumferential side of the core island 3, the first end of each of the lateral support members 2 is fixedly connected to the side of the second enclosure structure 31 away from the core island 3, and the second end of each of the lateral support members 2 is fixedly connected to the side of the first enclosure structure 11 away from the inner circumferential wall of the pit body 1. The core island 3 is located above the predicted position of the soil uplift at the bottom of the pit body 1, which helps to control the soil uplift at the bottom of the pit body 1 under the action of the gravity of the core island 3, thereby reducing the influence of the soil uplift on the stability of the internal support structure. Moreover, the arrangement of the core island 3 can shorten the length of the lateral support member 2, thereby further improving the stability of the internal support structure. Therefore, the deep and large foundation pit structure of the present application can improve the stability of the internal support structure. Specifically, the lateral support member 2 can transmit force with the help of the core island 3 to enhance the stability of the internal support structure, while weakening the influence of the deep and large foundation pit excavation on the surrounding environment, thereby reducing the construction cost of the internal support system.

[0032] Moreover, the upper end of at least one of the lateral support members 2 is provided with a trestle for transporting construction equipment from the outside of the pit body 1 to the upper end of the core island 3. The trestle is erected around the core island 3, and the excavator and the earth-moving truck can dig and transport earth through the trestle, which can effectively speed up the digging and earth-moving speed. The deep and large foundation pit structure of the present application avoids dividing the deep and large foundation pit into several small foundation pits for phased and regional construction, thereby reducing the construction cost and eliminating the safety risks faced by the breaking of piles between small foundation pits in the later stage.

[0033] The old city reconstruction period is often restricted by factors such as protection of ancient trees, famous trees and cultural relics and historical buildings. In the present embodiment, a remaining island for preserving famous trees, ancient trees and buildings not to be demolished is arranged in the pit body 1, the remaining island is arranged at intervals with the inner side wall of the pit body 1 and the core island 3, and the outer circumferential wall of the remaining island is provided with a third enclosure structure. The arrangement of the remaining island enables the preservation of buildings not to be demolished, ancient trees, famous trees, historical and cultural buildings.

[0034] Specifically, the retention island can be set in an area overlapping with the transverse support member, such as the first island body 41 and the second island body 42, and the retention island can also be set in an area without overlapping with the transverse support member, such as the third island body 43; when the retention island is set in an area without overlapping with the transverse support member, such as the third island body 43, the pit body 1 can be excavated after the construction of the third retaining structure is completed, wherein the third retaining structure includes support piles and water-stop piles arranged in sequence from close to the third island body 43 to far away from the third island body 43; in this embodiment, each of the transverse support members 2 includes a transversely arranged support frame, and the retention island is arranged in the middle of any one of the support frames, and a transition connection section is provided between the third retaining structure and the support frame, and the transition connection section is a radial truss structure or a support plate.

[0035] Specifically, when the retention island is set in an area that overlaps with the transverse support member, the basic principle of island force balance should be followed when designing the internal support structure around the first island body 41 and the third island body. When conditions permit, radial truss internal support should be used as much as possible, such as around the first island body 43. When radial truss internal support is not possible, support plates can be applied to the stress-bearing areas on both sides of the island body to increase the stress-bearing area, such as around the second island body 42, thereby reducing the force concentration on the retention island and enhancing the stability of the retention island. When the transverse support frame around the retention island is not truss-type but support plates are used, the length of the support plate is equal to the length of one span of the transverse support frame, and the thickness of the support plate is 300-400mm.

[0036] In this embodiment, the deep foundation pit structure includes a first annular beam 51 and a second annular beam 52. The first annular beam 51 is arranged around the inner wall of the pit body 1, and the outer side of the first annular beam 51 is fixedly connected to the side of the inner peripheral wall of the first enclosure structure 11 facing away from the pit body 1. The second annular beam 52 is arranged around the outer periphery of the core island 3, and the inner side of the second annular beam 52 is fixedly connected to the side of the second enclosure structure 31 facing away from the core island 3. The first end of each of the transverse supports 2 is fixedly connected to the inner side of the first annular beam 51, and the second end of each of the transverse supports 1 is fixedly connected to the outer side of the second annular beam 52. The provision of the first annular beam 51 and the second annular beam 52 ensures uniform force transmission of the inner support structure and improves the stability of the inner support structure.

[0037] Each of the transverse support members 2 includes a first transverse beam and a plurality of support columns arranged at intervals along the length direction of the corresponding first transverse beam for supporting the corresponding first transverse beam. Specifically, the lower end of each transverse support member 2 is connected to a vertically arranged support column.

[0038] A construction method for the above-mentioned deep and large foundation pit structure comprises the following steps:

[0039] Determine the design area of ​​the core island 3 and the positions of each transverse support member 2 according to the design area of ​​the pit body 1, so that the design area of ​​the core island 3 is located above the predicted position of the soil uplift at the bottom of the pit body 1;

[0040] A first enclosure structure 11 is constructed around the design area of ​​the pit body 1, and a second enclosure structure 31 is constructed around the design area of ​​the core island 3;

[0041] The pit body 1 is excavated layer by layer and each of the transverse support members 2 is constructed.

[0042] The location and structure of each horizontal support member 2 are determined based on the design area of ​​the core island 3 and the location of each retained island. Specifically, the design area of ​​the pit body 1 is specifically delineated according to the old city renovation plan. Once the design area of ​​the pit body 1 is determined, the number, location, and specific scope of the required retained islands are determined based on the design area of ​​the core island 3 and the scope and specific location of the remaining structures, ancient trees and historical and cultural relics that cannot be relocated within the pit body 1. The layout plan of the internal support structure within the pit body 1 is determined, including the layout plan of the horizontal supports.

[0043] During the construction of the first retaining structure 11, the pile position control line is determined according to the designated pit range, and the support piles and water-stop piles are constructed according to the process flow. Adjacent water-stop piles are interlocked until the construction of the first retaining structure 11 is completed. After the first retaining structure 11, the second retaining structure 31, and the third retaining structure are all completed and reach the designed strength, earthwork excavation can be carried out. Considering the large spatial scope of the core island 3, in order to ensure the stability of the soil during the excavation of the pit body 1, a row of water-stop piles must be driven along the inner boundary of the support piles of the first retaining structure 11.

[0044] Wherein, “excavating the pit body 1 layer by layer and constructing each of the transverse support members 2” includes:

[0045] When the pit body 1 is excavated to the first set depth, the first annular beam 51 , the second annular beam 52 and the transverse support member 2 are constructed.

[0046] Specifically, constructing the transverse support member 2 includes:

[0047] Insert each support column at the bottom of the pit body 1, and the height of each support column is greater than the total design depth of the pit body 1;

[0048] A first transverse support frame, a first annular frame arranged around the inner side wall of the pit body 1, and a second annular frame arranged around the outer periphery of the core island 3 are provided at the upper end of each support column;

[0049] The first transverse support frame, the first ring-shaped frame and the second ring-shaped frame are filled with concrete, the first transverse support frame filled with concrete forms a first transverse beam, the first ring-shaped frame filled with concrete forms a first ring-shaped beam 51, and the second ring-shaped frame filled with concrete forms a second ring-shaped beam 52.

[0050] The first set depth is the design elevation of the first layer of support, after the pit body is excavated to the first set depth, a second ring-shaped frame is arranged on the top of the support pile of the core island and a first ring-shaped frame is arranged on the top of the support pile of the first enclosure 11, and then the first ring-shaped frame, the second ring-shaped frame and the transverse beam are integrally poured. The thickness of the transverse beam is 1 meter.

[0051] After the concrete of the first transverse beam, the first ring-shaped beam 51 and the second ring-shaped beam 52 is solidified, the lower layer of earthwork excavation can be started, specifically, the pit body 1 is excavated to a second set depth, a second transverse support frame is fixedly connected to the middle of each support column, a third ring-shaped frame is arranged below the first ring-shaped beam 51 and fixed to the inner side of the pit body 1, a fourth ring-shaped frame is arranged below the second ring-shaped beam 52 and fixed to the outer side of the core island 3, and concrete is integrally poured in the third ring-shaped frame, the fourth ring-shaped frame and each second transverse support frame, the third ring-shaped frame filled with concrete forms a third ring-shaped beam 53, the fourth ring-shaped frame filled with concrete forms a fourth ring-shaped beam 54, and the second transverse support frame after being filled with concrete forms a second transverse beam 55. In this way, the excavation and support work of the pit body is completed.

[0052] In the embodiment, the support piles of the first enclosure 11, the second enclosure 31 and the third enclosure can be reinforced concrete bored piles, hole piles, pipe piles, etc., and the water stop piles are generally cement soil mixing piles. The general sequence of construction of the first enclosure 11 is support piles, water stop piles; when the support piles are reinforced concrete bored piles, the support piles must be constructed first, and then the water stop piles are constructed; when the support piles are pipe piles, the cement soil mixing piles can be constructed first, but the pipe piles must be timely set when the cement soil mixing piles have not completely solidified to avoid affecting the normal arrangement of the pipe piles. The first enclosure 11 is constructed first, and then the second enclosure 31 and the third enclosure are constructed; when the internal support of the detention island exceeds 15 meters, the vertical columns and the corresponding vertical column piles are arranged under the horizontal support members around the detention island. In the area adjacent to the enclosure and the core island, the horizontal support frame can be arranged in a large eight-character or truss type to enhance the stability of the internal support structure. The local area in the pit body 1 can be supplemented with anchor cables to reduce the arrangement of the horizontal support members, thereby avoiding affecting the construction of the building body 6. The horizontal support members located on both sides of the detention island should be symmetrically arranged on both sides of the detention island to ensure the overall stability of the detention island, thereby protecting the buildings or famous trees located on the detention island. When multiple horizontal support members are arranged, it should be ensured that the horizontal support members of the same layer are arranged at the same elevation, especially the horizontal support members on both sides of the detention island should be arranged at the same elevation to ensure smooth force transmission. Since the area of the detention island cannot be arranged with a basement, the basement layout scheme should be uniformly planned and designed in combination with the number, position and specific range of the detention island. When the pit body is excavated, the basic principles of supporting first and excavating later, layered excavation and prohibition of over-excavation should be followed. In the embodiment, the core island and the detention island are arranged in the core to fully mobilize the soil pressure of the core island and the detention island to balance the axial force transmitted by the internal support structure, and to meet the force transmission balance of the internal support around the core island and the detention island.

[0053] In summary, the deep and large foundation pit structure comprises a pit body 1 and a plurality of lateral support members 2, the inner circumferential wall of the pit body 1 is provided with a first enclosure structure 11, the middle part of the pit body 1 is provided with a core island 3, the core island 3 is located above the soil body uplift prediction position of the bottom of the pit body 1, and the outer circumferential wall of the core island 3 is provided with a second enclosure structure 31; each lateral support member 2 is arranged at intervals around the outer circumferential side of the core island 3, the first end of each lateral support member 2 is fixedly connected to the side of the second enclosure structure 31 away from the core island 3, and the second end of each lateral support member 2 is fixedly connected to the side of the first enclosure structure 11 away from the inner circumferential wall of the pit body 1. The core island 3 is located above the soil body uplift prediction position of the bottom of the pit body 1, which is helpful to control the soil body uplift of the bottom of the pit body 1 under the gravity of the core island 3, and reduces the influence of the soil body uplift on the stability of the internal support structure. Moreover, the setting of the core island 3 can shorten the length of the lateral support member 2, and further improve the stability of the internal support structure. Therefore, the deep and large foundation pit structure can improve the stability of the internal support structure.

[0054] The above description is only the preferred embodiments of the present application, and it should be pointed out that for ordinary skilled in the art, without departing from the technical principles of the present application, a number of improvements and replacements can be made, and these improvements and replacements should be considered as the protection scope of the present application.

Claims

1. A deep foundation pit structure, characterized in that: The invention comprises a pit body (1) and a plurality of transverse support members (2), wherein the inner peripheral wall of the pit body (1) is provided with a first enclosure structure (11), a core island (3) is provided in the middle of the pit body (1), and the core island (3) is located above the predicted position of soil uplift at the bottom of the pit body (1), and the outer peripheral wall of the core island (3) is provided with a second enclosure structure (31); each of the transverse support members (2) is arranged at intervals around the outer peripheral side of the core island (3), the first end of each of the transverse support members (2) is fixedly connected to the side of the second enclosure structure (31) away from the core island (3), and the second end of each of the transverse support members (2) is fixedly connected to the side of the first enclosure structure (11) away from the inner peripheral wall of the pit body (1); A retention island for preserving ancient trees or undemolished buildings is provided in the pit body (1), the retention island is spaced apart from the inner side wall of the pit body (1) and the core island (3), and a third enclosure structure is provided on the outer peripheral wall of the retention island; Each of the transverse support members (2) comprises a transversely arranged support frame, the retention island is arranged in the middle of any one of the support frames, a transition connection section is provided between the third enclosure structure and the support frame, and the transition connection section is a radial truss structure or a support plate.

2. The deep foundation pit structure according to claim 1, characterized in that: The upper end of at least one of the transverse supports (2) is provided with a trestle for transporting construction equipment from the outside of the pit body (1) to the upper end of the core island (3).

3. The deep foundation pit structure according to claim 1, characterized in that: The deep foundation pit structure comprises a first annular beam (51) and a second annular beam (52), wherein the first annular beam (51) is arranged around the inner wall of the pit body (1), and the outer side of the first annular beam (51) is fixedly connected to the side of the first enclosure structure (11) facing away from the inner wall of the pit body (1); the second annular beam (52) is arranged around the outer periphery of the core island (3), and the inner side of the second annular beam (52) is fixedly connected to the side of the second enclosure structure (31) facing away from the core island (3); The first end of each of the transverse support members (2) is fixedly connected to the inner side of the first annular beam (51), and the second end of each of the transverse support members (2) is fixedly connected to the outer side of the second annular beam (52).

4. The deep foundation pit structure according to claim 1, characterized in that: Each of the transverse support members (2) comprises a first crossbeam and a plurality of support columns arranged at intervals along the length direction of the corresponding first crossbeam and used for supporting the corresponding first crossbeam.

5. A construction method for a deep foundation pit structure according to any one of claims 1 to 4, characterized in that: The following steps are involved: Determining the design area of ​​the core island (3) and the positions of each transverse support member (2) according to the design area of ​​the pit body (1), so that the design area of ​​the core island (3) is located above the predicted position of soil uplift at the bottom of the pit body (1); A first enclosure structure (11) is constructed around the design area of ​​the pit body (1), and a second enclosure structure (31) is constructed around the design area of ​​the core island (3); The pit body (1) is excavated layer by layer and each of the transverse support members (2) is constructed.

6. The construction method of the deep foundation pit structure according to claim 5, characterized in that: The position and structure of each of the transverse support members (2) are determined according to the design area of ​​the core island (3) and the position of each of the retained islands.

7. The construction method of a deep foundation pit structure according to claim 5, characterized in that: "Excavating the pit body (1) layer by layer and constructing each of the transverse support members (2)" includes: When the pit body (1) is excavated to a first set depth, a first ring beam (51), a second ring beam (52) and a transverse support member (2) are constructed; The construction of the transverse support member (2) comprises: Inserting each support column at the bottom of the pit body (1), wherein the height of each support column is greater than the total designed depth of the pit body (1); A first transverse support frame, a first annular frame arranged around the inner side wall of the pit body (1), and a second annular frame arranged around the outer periphery of the core island (3) are provided at the upper end of each support column; Concrete is poured into the first transverse support frame, the first annular frame and the second annular frame. The first transverse support frame poured with concrete forms a first transverse beam, the first annular frame poured with concrete forms a first annular beam (51), and the second annular frame poured with concrete forms a second annular beam (52).

8. The construction method of the deep foundation pit structure according to claim 7, characterized in that: After the concrete of the first cross beam, the first ring beam (51) and the second ring beam (52) solidifies, the method comprises: The pit body (1) is excavated downward to a second set depth, a second transverse support frame is fixedly connected to the middle of each support column, a third annular frame is arranged below the first annular beam (51), and the third annular frame is fixed to the inner side of the pit body (1); a fourth annular frame is arranged below the second annular beam (52), and the fourth annular frame is fixed to the outer side of the core island (3); concrete is integrally poured in the third annular frame, the fourth annular frame and each of the second transverse support frames, the third annular frame after pouring concrete forms a third annular beam (53), the fourth annular frame after pouring concrete forms a fourth annular beam (54), and the second transverse support frame after pouring concrete forms a second transverse beam (55).

Images