An assembled steel sheet pile outer support device and construction method

Abstract

The application provides an assembled steel sheet pile outer support device, which comprises N assembled outer support standard units, channel steel and steel strand; the assembled outer support standard unit is arranged outside the foundation pit mouth, the channel steel is close to the inner side of the Larsen steel sheet pile, and the N assembled outer support standard units are fixedly connected with the Larsen steel sheet pile and the channel steel through the steel strand; the N assembled outer support standard units comprise steel enclosing purlin and steel support, the steel enclosing purlin is arranged outside both sides of the foundation pit mouth, and the steel support across the foundation pit mouth is fixedly connected with the steel enclosing purlin outside both sides of the foundation pit mouth; the Larsen steel sheet pile in the foundation pit, the steel enclosing purlin outside the foundation pit mouth and the channel steel close to the inner side of the Larsen steel sheet pile are uniformly and intervally provided with holes at corresponding positions, and a plurality of steel strands are used to fix the steel enclosing purlin on the same side, the Larsen steel sheet pile and the channel steel through the holes. The application further discloses a construction method of the assembled steel sheet pile outer support. The application increases the available space in the foundation pit, effectively reduces the width of the foundation pit and the earthwork excavation amount, reduces the engineering cost and improves the work efficiency.

Description

Technical Field

[0001] This invention relates to the field of building curtain wall technology, and in particular to a prefabricated steel sheet pile external support device and its construction method. Background Technology

[0002] Due to the complex underground pipelines, numerous unknown pipelines, and proximity to existing buildings and structures in old urban areas and communities, the space for constructing underground pipelines and facilities is extremely limited, severely restricting the progress of project construction. The prerequisite for the implementation of underground structures is that the proposed site can meet the requirements for earthwork excavation, foundation pit support, and construction working surfaces. In old urban areas and communities, there is no space for sloping excavation, necessitating vertical support, the most common method being steel sheet piles with internal bracing. Because the internal bracing steel walers are located inside the foundation pit, they encroach on the underground structural space and construction space, often resulting in insufficient construction space to proceed, or insufficient underground structural space to meet design requirements, thus preventing project implementation. These problems are particularly prominent in the renovation and upgrading of underground stormwater and sewage pipelines in old urban areas and communities.

[0003] Prefabricated structures have a long history of development in my country, and they offer advantages such as high standardization and reusability. Standardizing commonly used components not only achieves standardization but also increases construction efficiency and reduces construction time by leveraging their ease of reusability and installation. Summary of the Invention

[0004] To overcome the problems existing in the prior art, the present invention provides a prefabricated steel sheet pile external support device and its construction method. The standardized prefabricated steel sheet pile external support device is adjusted to the outside of the foundation pit, which increases the usable space inside the foundation pit, effectively reduces the width of the foundation pit and the amount of earthwork excavation, reduces the project cost, improves work efficiency, and is more conducive to protecting the surrounding existing buildings and structures.

[0005] A prefabricated steel sheet pile external support device, wherein Larssen steel sheet piles are installed on both sides of the foundation pit, and includes prefabricated external support standard units, channel steel and steel strands; The prefabricated external support standard unit is set outside the pit opening, and the channel steel is closely attached to the inner side of the Larssen steel sheet pile. N prefabricated external support standard units are fixedly connected to the Larssen steel sheet pile and the channel steel through steel strands. N prefabricated external support standard units include steel walers and steel supports. The steel walers are set on both sides outside the pit opening, and the two ends of the steel supports that span the pit opening are fixedly connected to the steel walers on both sides outside the pit opening. The elevation of the Larssen sheet piles under the steel support is 0.5m lower than that of the Larssen sheet piles not under the steel support. Holes are evenly spaced at corresponding positions of the Larssen sheet piles inside the pit, the steel walers outside the pit opening, and the channel steel closely attached to the inner side of the Larssen sheet piles. Multiple steel strands pass through the holes to fix the steel walers on the same side to the Larssen sheet piles and the channel steel.

[0006] Furthermore, the standard unit of the prefabricated external support has a length of 5.6m and a width range of 2-6m, and the N units are greater than or equal to 1 unit.

[0007] Furthermore, different widths of prefabricated external support standard units correspond to different lengths of steel supports, including 1-meter, 2-meter, and 3-meter steel supports.

[0008] Furthermore, the length of the prefabricated external support standard unit corresponds to the length of the steel walers on both sides, which is 5.6m.

[0009] Furthermore, the Larssen sheet pile includes U-shaped steel plates, with the U-shaped steel plates facing outwards and those facing inwards sequentially interlocked to form the Larssen sheet pile. The steel waler is fixedly connected to the U-shaped steel plates facing outwards and the channel steel via steel strands. The elevation of the U-shaped steel plates facing inwards with steel supports is 0.5m lower than the elevation of the U-shaped steel plates without steel supports. The steel supports are fixedly connected to the steel waler with high-strength bolts on the U-shaped steel plates facing inwards with the lower elevation (0.5m lower).

[0010] Furthermore, the holes are evenly spaced at a distance of 0.8m.

[0011] Furthermore, the steel strand is 1.2m long and 15.24mm in diameter. The steel strand passes through the hole and is tensioned and fixed at both ends with single-hole anchor heads to the steel waler and the U-shaped steel plate and channel steel with the U-shaped opening facing out of the pit.

[0012] The second technical solution provided by this invention is: A construction method for a prefabricated steel sheet pile external support device includes the following steps: Positioning and layout → Larssen sheet pile driving → Ground elevation re-measurement → Assembly of prefabricated external support standard unit → Setting the assembled prefabricated external support standard unit at the pit opening → Fitting the channel steel tightly against the inside of the Larssen sheet pile → Installing and tensioning the steel strand → Earthwork excavation → Structural construction → Earthwork backfilling → Removing the steel strand → Removing the channel steel → Removing the prefabricated external support standard unit.

[0013] Furthermore, in the assembly of the prefabricated external support standard unit, two steel supports are spaced 4 meters apart, and the two ends of the two steel supports are fixedly connected to the two steel walers by high-strength bolts.

[0014] Furthermore, the assembled prefabricated external support standard unit is set on the pit opening. Specifically, the steel walers in the prefabricated external support standard unit are set on both sides of the pit opening, and the steel support spans across the pit opening. In the process of tightly attaching the channel steel to the inside of the Larssen steel sheet pile, the channel steel is tightly attached to the inside of the Larssen steel sheet pile, and the holes on the corresponding positions of the Larssen steel sheet pile, the channel steel, and the steel waler are aligned.

[0015] The beneficial effects of this invention are as follows: (1) The prefabricated external support standard unit is made of steel walers and steel supports, which are connected by high-strength bolts. It has the advantages of high overall rigidity, high load-bearing capacity and small deformation. The prefabricated external support standard unit can form an independent force system, and the force influence between each standard unit is small. (2) The steel walers are heavy and are set on the outside of the foundation pit, making installation more convenient, eliminating the risk of falling, and increasing the usable space inside the foundation pit; (3) A channel steel is installed on the inner side of the Larssen sheet pile, and steel strands are used to fix the Larssen sheet pile to the channel steel and the steel waler. The steel strands can be prestressed to effectively control the deformation of the foundation pit and ensure the safety of the surrounding existing buildings and structures. The channel steel and steel strands will evenly transfer the soil pressure of the Larssen sheet pile to the outer steel waler. Compared with the existing technology where the steel waler directly bears the soil pressure on the sheet pile, the stress is more reasonable and the support is more stable. (4) The steel supports of different lengths in the prefabricated external support device can be used in the construction of foundation pits with a width of 2 to 6m. Multiple prefabricated external support standard units are connected by high-strength bolts to be used in the construction of foundation pits of different lengths. The standardization of the prefabricated external support device has the advantages of on-site assembly, convenient component manufacturing, transportation, installation and dismantling, fast construction speed, reusability and cost saving. Attached Figure Description

[0016] Figure 1 The present invention provides a top view of a prefabricated steel sheet pile external support device comprising a standard prefabricated external support unit structure. Figure 2 The present invention provides a top view of a prefabricated steel sheet pile external support device comprising two prefabricated external support standard unit structures. Figure 3 A top view of a standard unit structure of an assembled external support in an assembled steel sheet pile external support device according to the present invention. Figure 4 Top view of the Larssen sheet pile installation structure in an assembled steel sheet pile external support device of the present invention; Figure 5 A top sectional view of the connection structure between the steel support and the steel waler in an assembled steel sheet pile external support device of the present invention.

[0017] Explanation of symbols in the attached diagram: 1. Prefabricated external support standard unit; 2. Foundation pit; 3. Channel steel; 4. Larssen sheet piles; 5. Steel strand; 6. Steel waler. 7. Steel support; 8. U-shaped steel plate; 9. Second high-strength bolt; 10. Single-hole anchor head; 11. First high-strength bolt. 12. Flange connection plate. Detailed Implementation

[0018] To enable those skilled in the art to better understand the technical solution of the present invention, the present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0019] The accompanying drawings are for illustrative purposes only and are schematic diagrams, not actual images. They should not be construed as limiting the scope of this patent. To better illustrate the embodiments of the present invention, some parts in the drawings may be omitted, enlarged, or reduced, and do not represent the actual dimensions of the product. It is understandable to those skilled in the art that some well-known structures and their descriptions may be omitted in the drawings.

[0020] In the accompanying drawings of the embodiments of the present invention, the same or similar reference numerals correspond to the same or similar components. In the description of the present invention, it should be understood that if terms such as "upper," "lower," "left," "right," "inner," and "outer" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the drawings, they are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, the terms used to describe positional relationships in the drawings are only for illustrative purposes and should not be construed as limiting the present patent. For those skilled in the art, the specific meaning of the above terms can be understood according to the specific circumstances.

[0021] In the description of this patent, unless otherwise explicitly specified and limited, the term "connection" or similar designation indicating a connection between components should be interpreted broadly. For example, it can refer to a fixed connection, a detachable connection, or an integral part; 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 refer to the internal communication between two components or the interaction between two components. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0022] This invention discloses a prefabricated steel sheet pile external support device and construction method, such as... Figures 1 to 5As shown, a prefabricated steel sheet pile external support device includes Larssen steel sheet piles 4 installed on both sides of a foundation pit 2, and N prefabricated external support standard units 1, channel steel 3, and steel strands 5. The N prefabricated external support standard units 1 are installed outside the foundation pit 2 opening. The channel steel 3 is tightly attached to the inner side of the Larssen steel sheet piles 4. The N prefabricated external support standard units 1 are fixedly connected to the Larssen steel sheet piles 4 and the channel steel 3 via steel strands 5. The N prefabricated external support standard units 1 are also fixedly connected to each other via first high-strength bolts 11. Each prefabricated external support standard unit 1 includes a steel waler. 6 and steel support 7, the steel waler 6 is set on both sides outside the pit 2 opening, the two ends of the steel support 7 spanning the pit opening are fixedly connected to the steel waler 6 on both sides outside the pit 2 opening; the elevation of the Larssen steel sheet pile 4 below the steel support 7 is 0.5m lower than the elevation of the Larssen steel sheet pile 4 not below the steel support 7, the Larssen steel sheet pile 4 inside the pit 2, the steel waler 6 outside the pit 2 opening, and the channel steel 3 closely attached to the inner side of the Larssen steel sheet pile 4 are all evenly spaced with holes, multiple steel strands 5 pass through the holes to fix the steel waler 6, Larssen steel sheet pile 4, and channel steel 3 on the same side. The existing steel sheet pile support device sets the steel waler in the pit, which requires a bracket to support the steel waler, and the steel waler occupies space in the pit. If the pit space is narrow, it will lead to the problem of the project being unable to be implemented. Based on the technical problems encountered in engineering, this invention proposes a device for external support of steel sheet piles. According to the standard dimensions of steel sheet piles and conventional dimensions used in engineering practice, a standardized external support device for steel sheet piles is designed, namely, a prefabricated external support device for steel sheet piles. The detailed structure is shown above. N prefabricated external support standard units 1 are constructed using steel walers and steel supports, connected by high-strength bolts. This design offers advantages such as high overall rigidity, high load-bearing capacity, and low deformation. Each prefabricated external support standard unit can form an independent force-bearing system, with minimal force influence between standard units. The N prefabricated external support standard units 1 are fixedly connected to each other by a first high-strength bolt 11. Each prefabricated external support standard unit 1 includes a steel waler 6 and a steel support 7. The N prefabricated external support standard units 1 are fixedly connected to each other by the first high-strength bolt 11, which also means that the steel walers 6 are fixedly connected by the first high-strength bolt 11. The steel walers 6 are I-beams. The connection structure between the steel walers 6 consists of flange connecting plates 12 welded to the connecting ends of the steel walers 6, with bolt holes on the flange connecting plates 12. A first high-strength bolt 11 passes through the bolt holes on the two flange connecting plates 12 to fix and connect the adjacent steel walers 6. This technical solution, a prefabricated steel sheet pile external support device, not only solves the technical problem of limited excavation space preventing construction, but also offers advantages over existing technologies where the steel walers directly bear the soil pressure on the steel sheet piles, resulting in more reasonable stress distribution and more stable support. The standardization of this prefabricated steel sheet pile external support device also offers advantages such as convenient on-site assembly, component fabrication, transportation, installation, and dismantling, as well as fast construction speed, reusability, and cost savings.

[0023] Furthermore, such as Figures 1 to 5 As shown, the prefabricated external support standard unit 1 has a length of 5.6m and a width ranging from 2-6m. The number N is greater than or equal to 1. Based on the standard Larssen sheet pile 4 having a length of 400mm and a steel strand 5 spacing of 0.8m, the length of the prefabricated external support standard unit 1 is set to 5.6m. Based on the standard pit width of 2-6m, the width range of the prefabricated external support standard unit is set to 2-6m. The number N of prefabricated external support standard units is greater than or equal to 1. One prefabricated external support standard unit, together with channel steel 3 and steel strand 5, connects with the Larssen sheet pile 4 in the pit to form a prefabricated steel sheet pile external support device for the construction of one section of the pit. After one section of the pit is completed, the process repeats, using one prefabricated external support standard unit, channel steel 3, and steel strand 5, to connect with the Larssen sheet pile 4 in the pit to form the prefabricated steel sheet pile external support device for the construction of the next section of the pit. Alternatively, there can be N units, such as 2 or 3 prefabricated external support standard units. Two prefabricated external support standard units are connected by high-strength bolts, and multiple connections can be made to form the length of the foundation pit. These are then combined with channel steel 3 and steel strand 5 to connect with Larssen steel sheet piles 4 inside the foundation pit, forming a prefabricated steel sheet pile external support device for foundation pit construction. Alternatively, two prefabricated external support standard units can be reused, with one additional prefabricated external support standard unit, for repeated foundation pit construction.

[0024] Furthermore, such as Figures 1 to 5 As shown, different widths of prefabricated external support standard unit 1 correspond to different lengths of steel supports 7. These steel supports 7 include 1-meter, 2-meter, and 3-meter lengths. The length of prefabricated external support standard unit 1 corresponds to the length of the two side steel walers 6, which are 5.6m long. The steel supports, using lengths of 1m, 2m, and 3m, can be combined to form steel supports ranging from 2 to 6m in length, adaptable to foundation pits 2 to 6m wide. The two side steel walers 6 are 5.6m long. Based on the standard Larssen sheet pile length and the 0.8m distance between the steel strands 5, the length of one prefabricated external support standard unit 1 is set to be the same as the length of the steel walers 6, which can include the length of 14 standard Larssen sheet piles. The steel walers 6 on both sides, each 5.6m long, can be reused along the length of the foundation pit 4, which is one prefabricated external support standard unit 1. Alternatively, N prefabricated external support standard units 1 can be connected to each other by high-strength bolts to form one unit for foundation pit 4 construction.

[0025] Furthermore, such as Figures 1 to 5As shown, the Larssen sheet pile 4 includes U-shaped steel plates 8. The U-shaped steel plates 8 with their U-shaped openings facing outwards and those facing inwards are sequentially fastened together to form the Larssen sheet pile 4. The steel waler 6 is fixedly connected to the U-shaped steel plates 8 with their U-shaped openings facing outwards and the channel steel 3 via steel strands 5. The elevation of the U-shaped steel plates 8 with their U-shaped openings facing inwards, which have steel supports 7 on top, is 0.5m lower than the elevation of the U-shaped steel plates 8 without steel supports 7. The steel supports 7 are fixedly connected to the second high-strength bolt 9 of the steel waler 6 on top of the U-shaped steel plates with their U-shaped openings facing inwards, which are 0.5m lower in elevation. Analysis of the pressure transmission within the foundation pit wall shows that fixing the steel waler 6 to the U-shaped steel plates 8 with their U-shaped openings facing outwards and the channel steel 3 via steel strands 5 is the optimal way to transmit the pressure within the foundation pit wall. Therefore, this connection structure is chosen to improve the supporting capacity of the external support of the sheet pile. Through repeated practice, it has been found that setting the elevation of the U-shaped steel plate 8 with the steel support 7 on top and the U-shaped opening facing into the pit 0.5m lower than the elevation of the U-shaped steel plate 8 without the steel support 7 on top allows for the fixed connection of both ends of the steel support 7 to the steel walers 6 on both sides of the pit opening using high-strength bolts. Both the steel support 7 and the steel walers 6 are I-beams. Flange connecting plates 12 are welded at the connection points of the steel support 7 and the steel walers, and bolt holes are provided on the flange connecting plates 12. The steel walers 6 are connected to the steel support 7 by welding flange connecting plates 12, and bolt holes are provided on the flange connecting plates 12. Second high-strength bolts 9 pass through the bolt holes on the two flange connecting plates 12 to fix the steel support 7 and the steel walers 6.

[0026] Furthermore, such as Figures 1 to 5 As shown, the holes are evenly spaced at a distance of 0.8m. Furthermore, the steel strand 5 is 1.2m long and has a diameter of 15.24mm. The steel strand 5 passes through the holes, and both ends are tensioned and fixedly connected to the steel waler 6 and the U-shaped steel plate 8 and channel steel 3 with the U-shaped opening facing out of the pit using single-hole anchor heads 10.

[0027] This invention also discloses a construction method for a prefabricated steel sheet pile external support device, comprising the following steps: Positioning and layout → Larssen sheet pile driving → Ground elevation re-measurement → Assembly of prefabricated external support standard unit → Setting the assembled prefabricated external support standard unit at the pit opening → Fitting the channel steel tightly against the inside of the Larssen sheet pile → Installing and tensioning the steel strand → Earthwork excavation → Structural construction → Earthwork backfilling → Removing the steel strand → Removing the channel steel → Removing the prefabricated external support standard unit.

[0028] Furthermore, in assembling the standard unit of the prefabricated external support, two steel supports are spaced 4 meters apart, and the two ends of the two steel supports are fixedly connected to the two steel walers by high-strength bolts.

[0029] Furthermore, the assembled prefabricated external support standard unit is set on the pit opening, which means that the steel walers in the prefabricated external support standard unit are set on both sides of the pit opening, and the steel support spans the pit opening.

[0030] Furthermore, in the process of tightly attaching the channel steel to the inside of the Larssen sheet pile, the channel steel is tightly attached to the inside of the Larssen sheet pile, and the holes at the corresponding positions of the Larssen sheet pile, the channel steel, and the steel waler are aligned.

[0031] It should be stated that the above-described specific embodiments are merely preferred embodiments of the present invention and the technical principles employed. Those skilled in the art should understand that various modifications, equivalent substitutions, and variations can be made to the present invention. However, such variations, as long as they do not depart from the spirit of the present invention, should be within the scope of protection of the present invention. Furthermore, some terminology used in this specification and claims is not limiting, but merely for ease of description.

Claims

1. A prefabricated steel sheet pile external support device, wherein Larssen steel sheet piles (4) are installed on both sides inside the foundation pit (2), characterized in that, It includes N prefabricated external support standard units (1), channel steel (3) and steel strand (5); N prefabricated external support standard units (1) are set outside the pit (2) opening, the channel steel (3) is closely attached to the inner side of the Larssen steel sheet pile (4), the N prefabricated external support standard units (1), the Larssen steel sheet pile (4) and the channel steel (3) are fixedly connected by steel strand (5), and the N prefabricated external support standard units (1) are fixedly connected to each other by the first high-strength bolt (11); The prefabricated external support standard unit (1) includes a steel waler (6) and a steel support (7). The steel waler (6) is set on both sides outside the pit (2) opening. The two ends of the steel support (7) spanning the pit opening are fixedly connected to the steel waler (6) on both sides outside the pit (2) opening. The elevation of the Larssen sheet piles (4) under the steel support (7) is 0.5m lower than that of the Larssen sheet piles (4) not under the steel support (7). Holes are evenly spaced at corresponding positions of the Larssen sheet piles (4) in the pit (2), the steel walers (6) outside the pit (2) opening, and the channel steel (3) close to the inner side of the Larssen sheet piles (4). Multiple prestressed steel strands (5) pass through the holes to fix the steel walers (6) on the same side to the Larssen sheet piles (4) and the channel steel (3). The length of one of the prefabricated external support standard units (1) includes the length of several standard Larssen sheet piles (4).

2. The prefabricated steel sheet pile external support device according to claim 1, characterized in that, The prefabricated external support standard unit (1) has a length of 5.6m and a width range of 2-6m, and the N units are greater than or equal to 1 unit.

3. The prefabricated steel sheet pile external support device according to claim 2, characterized in that, Different width prefabricated external support standard unit (1) corresponds to different lengths of steel support (7). The different lengths of steel support (7) include 1-meter long steel support (7), 2-meter long steel support (7) and 3-meter long steel support (7). The length of the prefabricated external support standard unit (1) corresponds to the length of the steel walers (6) on both sides. The steel walers (6) on both sides are 5.6m.

4. The prefabricated steel sheet pile external support device according to claim 1, characterized in that, The Larssen sheet pile (4) includes a U-shaped steel plate (8). The U-shaped steel plate (8) with the U-shaped opening facing out of the pit and the U-shaped steel plate (8) with the U-shaped opening facing in the pit are sequentially fastened to form the Larssen sheet pile (4). The steel waler (6), the U-shaped steel plate (8) with the U-shaped opening facing out of the pit, and the channel steel (3) are fixedly connected by steel strands (5). The elevation of the U-shaped steel plate (8) with the U-shaped opening facing in the pit with the steel support (7) on top is 0.5m lower than the elevation of the U-shaped steel plate (8) without the steel support (7) on top. The steel support (7) is fixedly connected to the steel waler (6) on the U-shaped steel plate with the U-shaped opening facing in the pit with the elevation 0.5m lower by a second high-strength bolt (9).

5. The prefabricated steel sheet pile external support device according to claim 1, characterized in that, The holes are evenly spaced at a distance of 0.8m.

6. The prefabricated steel sheet pile external support device according to claim 1, characterized in that, The steel strand (5) is 1.2m long and 15.24mm in diameter. The steel strand (5) passes through the hole and is tensioned and fixed at both ends by single-hole anchor heads (10) to connect the steel waler (6) with the U-shaped steel plate (8) and channel steel (3) facing out of the pit.

7. A construction method for the prefabricated steel sheet pile external support device according to any one of claims 1-6, characterized in that, Includes the following steps: Positioning and layout → Larssen sheet pile driving → Ground elevation re-measurement → Assembly of prefabricated external support standard unit → Setting the assembled prefabricated external support standard unit at the pit opening → Fitting the channel steel tightly against the inside of the Larssen sheet pile → Installing and tensioning the steel strand → Earthwork excavation → Structural construction → Earthwork backfilling → Removing the steel strand → Removing the channel steel → Removing the prefabricated external support standard unit.

8. The construction method according to claim 7, characterized in that, In the assembly of the prefabricated external support standard unit, two steel supports are spaced 4 meters apart, and the two ends of the two steel supports are fixedly connected to the two steel walers by high-strength bolts.

9. The construction method according to claim 7, characterized in that, The assembled prefabricated external support standard unit is set on the pit opening, which means that the steel walers in the prefabricated external support standard unit are set on both sides of the pit opening, and the steel support spans the pit opening.

10. The construction method according to claim 7, characterized in that, In the process of tightly attaching the channel steel to the inside of the Larssen sheet pile, the channel steel is tightly attached to the inside of the Larssen sheet pile, and the holes at the corresponding positions of the Larssen sheet pile, the channel steel, and the steel waler are aligned.

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