Steel pipe pile foundation pit support

Abstract

The utility model relates to the technical field of foundation pit construction, disclose a kind of steel pipe pile foundation pit support, the pit wall of foundation pit is arranged with steel pipe pile array, steel pipe pile array includes steel pipe pile monomer, steel pipe pile monomer vertical arrangement and along its length direction spacing arrangement of pit wall and the lower end of steel pipe pile monomer extends to the basement below of foundation pit, the pit wall of foundation pit is provided with horizontally arranged waist beam and waist beam is arranged in parallel with steel pipe pile array, the soil body between the opposite side pit wall of two adjacent foundation pits is provided with the cable-through hole passing through the soil body, the pit cavity of two foundation pits is communicated by cable-through hole, and prestressed cable is arranged through cable-through hole, and the two ends of prestressed cable are connected with the waist beam on the opposite side pit wall of two foundation pits respectively. Two foundation pits opposite side pit wall share same prestressed cable and same cable-through hole, not only beneficial to reduce the drilling operation amount of cable-through hole, while the steel pipe pile array of two adjacent foundation pits is mutually constrained each other, effectively suppresses pit wall earthwork collapse.

Description

Technical Field

[0001] This utility model relates to the field of foundation pit construction technology, specifically to a steel pipe pile foundation pit support. Background Technology

[0002] An excavation pit is the space below ground level excavated for the construction of building foundations and basements. To prevent the pit walls from collapsing after excavation, it is generally necessary to build supports within the pit to support the excavated soil. Common forms of support include soil nailing walls, retaining walls, and steel pipe piles, etc.

[0003] In conventional steel pipe pile support construction, the installation of a lintel beam can support and constrain the steel pipe pile body, preventing it from tilting inwards into the pit (such as the steel pipe Larssen sheet pile dewatering retaining structure disclosed in CN109610476A). For each lintel beam on the pit wall, separate cable-passing channels need to be drilled in the pit wall to install anchor cables or anchor rods for later tightening of the lintel beam. However, during the construction of building foundation pit support, demolition often cannot be carried out on time, and adjacent foundation pits are often excavated simultaneously with a certain space between them. This significantly increases the drilling workload of cable-passing channels during foundation pit support construction, and interference can easily occur between the cable-passing channels on the opposite sidewalls of adjacent foundation pits. Therefore, a steel pipe pile foundation pit support and its construction method are proposed to solve these problems. Utility Model Content

[0004] The purpose of this application is to provide a steel pipe pile foundation pit support that reduces the drilling workload and construction difficulty of cable-stayed tunnels, and improves the efficiency of foundation pit construction.

[0005] To achieve the above objectives, the technical solution adopted is as follows: a steel pipe pile foundation pit support, wherein a steel pipe pile array is arranged on the pit wall, the steel pipe pile array includes individual steel pipe piles, the individual steel pipe piles are arranged vertically and spaced along the length of the pit wall, and the lower end of the individual steel pipe piles extends to the bottom of the pit. A horizontally arranged waist beam is provided on the pit wall, and the waist beam is arranged parallel to the steel pipe pile array. The waist beam is located on the side of the steel pipe pile array near the center of the pit. A cable-passing channel is provided in the soil between the opposite sides of the pit walls of two adjacent pits, and the pit cavities of the two pits are connected through the cable-passing channel. The prestressed cable passes through the cable-passing channel and the two ends of the prestressed cable are respectively connected to the waist beam on the opposite sides of the pit walls of the two pits.

[0006] Compared with the prior art, the technical effect of this application is as follows: a cable-passing channel is set in the soil between the opposite sides of the pit walls of two adjacent foundation pits, and the pit cavities of the two foundation pits are connected through the cable-passing channel. The prestressed cable passes through the cable-passing channel and the two ends of the prestressed cable are respectively connected to the waist beam on the opposite side of the pit walls of the two foundation pits. This allows the prestressed cable to be used for fastening the waist beam on the pit walls of the two foundation pits at the same time. The two foundation pits share the same prestressed cable and the same cable-passing channel on the opposite side of the pit walls. This not only helps to reduce the amount of drilling work for the cable-passing channel and avoid the interference problem of the cable-passing channels on the opposite side of the pit walls of the two adjacent foundation pits, but also allows the steel pipe pile arrays of the two adjacent foundation pits to constrain each other and effectively suppress the collapse of the pit wall soil. Attached Figure Description

[0007] Figure 1 This is a schematic diagram of the present application;

[0008] Figure 2 This is a schematic diagram of the front of the pit wall.

[0009] Figure 3 This is a partial top view of the structure;

[0010] Figure 4 for Figure 1 Enlarged view of part M in the image;

[0011] Figure 5 for Figure 2 Enlarged view of part N in the image;

[0012] Figure 6 This is a schematic diagram of the support structure. Detailed Implementation

[0013] The following is in conjunction with the appendix Figure 1-6 This application will be further described in detail with reference to relevant content.

[0014] A steel pipe pile foundation pit support is provided. A steel pipe pile array 10 is arranged on the pit wall of the foundation pit A. The steel pipe pile array 10 includes individual steel pipe piles 11. The individual steel pipe piles 11 are arranged vertically and spaced along the length of the pit wall. The lower end of the individual steel pipe piles 11 extends to the bottom of the foundation pit A. A horizontally arranged waist beam 20 is provided on the pit wall of the foundation pit A and is arranged parallel to the steel pipe pile array 10. The waist beam 20 is located on the side of the steel pipe pile array 10 near the center of the foundation pit A. A cable-passing channel B1 is provided in the soil B between the opposite pit walls of two adjacent foundation pits A. The pit cavities of the two foundation pits A are connected through the cable-passing channel B1. Prestressed cables 30 are inserted through the cable-passing channel B1 and the two ends of the prestressed cables 30 are respectively connected to the waist beam 20 on the opposite pit walls of the two foundation pits A.

[0015] In the above technical solution, the prestressed cable 30 in one cable-passing duct B1 can be used simultaneously for the fastening of the waist beam 20 on the walls of the two foundation pits A. The two foundation pits A share the same prestressed cable 30 and the same cable-passing duct B1 on opposite sides of the pit walls. This not only helps to reduce the amount of drilling work in the cable-passing duct B1 and avoids interference problems between the cable-passing ducts B1 on opposite sides of the two adjacent foundation pits A, but also allows the steel pipe pile arrays 10 of the two adjacent foundation pits A to constrain each other, forming a tension-type pre-tightening, which effectively suppresses the collapse of the pit wall soil.

[0016] As a preferred embodiment, the cable-passing channel B1 is a long straight hole with its core direction in the horizontal direction, and the cable-passing channel B1 is located between two adjacent steel pipe pile units 11 on the steel pipe pile array 10.

[0017] Furthermore, such as Figure 3 As shown, considering the long walls of pit A, a single prestressed cable 30 cannot hold the entire wainscoting 20. Therefore, cable-passing ducts B1 are arranged at intervals along the length of the wainscoting 20 and are respectively set between two adjacent steel pipe pile units 11. Multiple cable-passing ducts B1 are set up to connect to the wainscoting 20 through multiple prestressed cables 30, so as to better fix the wainscoting 20.

[0018] Furthermore, to connect and fix the prestressed cable 30 to the lintel 20, an anchor 21 is installed on the side of the lintel 20 facing away from the steel pipe pile array 10. The free end of the prestressed cable 30 passes sequentially through the through hole of the lintel 20 and the cable hole on the anchor 21, and is anchored by the anchor 21. In this scheme, using the anchor 21 to connect and fix the prestressed cable 30 to the lintel 20 allows for pre-tensioning of the prestressed cable 30, effectively restraining the lintel 20 to the steel pipe pile array 10 and preventing it from moving freely.

[0019] As a preferred embodiment, the lumbar beam 20 comprises two channel steels 22 with their openings facing away from each other and their bottoms opposite each other. The two channel steels 22 are arranged parallel vertically, with their ends extending towards the corner of the pit wall A. The bottoms of the two channel steels 22 are spaced apart. The outer walls of the two channel steels 22 near the end of the cable-passing hole B1 are welded together by steel pads 23. Anchors 21 are set on the steel pads 23 on the side closest to the center of pit A. The free ends of the prestressed cables 30 pass through the through holes on the steel pads 23 and the gap between the two channel steels 22 into the cable-passing holes on the anchors 21. Using channel steels 22, which are commonly found on construction sites, to make the lumbar beam 20 is convenient, simple to manufacture, and can meet the requirements for sufficient support strength.

[0020] As a preferred embodiment, a support member 40 is provided on the side of the steel pipe pile array 10 near the center of the foundation pit A. The support member 40 supports the lower end face of the waist beam 20 and restricts the downward displacement of the waist beam 20. In this embodiment, the support member 40 is provided to support the waist beam 20. On the one hand, it can prevent the waist beam 20 from sagging, which would cause shearing action between the prestressed cable 30 and the edge of the cable passage B1, affecting the service life of the prestressed cable 30. On the other hand, when the waist beam 20 is erected on the steel pipe pile array 10, it can be supported immediately. After the crane lifts the waist beam 20 onto the support member 40, the crane can be moved away. There is no need for the crane to lift the waist beam 20 until the prestressed cable 30 is threaded and tightened, thus reducing the equipment occupancy rate.

[0021] Furthermore, combined Figure 4 and Figure 6 As shown, the supporting member 40 includes a flat support platform 41. One end of the support platform 41 adjacent to the steel pipe pile array 10 is connected to a vertically positioned, downwardly extending connecting plate 42. The connecting plate 42 is connected to the opposite steel pipe pile unit 11. A plate-shaped reinforcing rib 43, with its surface perpendicular to both the connecting plate 42 and the lower end face of the support platform 41, is connected between the outer surface of the connecting plate 42 and the lower end face of the support platform 41. The waist beam 20 rests on the platform 41. In this design, the support platform 41 supports the waist beam 20, and the connecting plate 42, integrally formed with the support platform 41, is welded to the steel pipe pile unit 11 to fix the supporting member 40. Because the supporting member 40 is located below the waist beam 20, there is ample space below, and it is not limited by structural space. The welding operation between it and the steel pipe pile unit 11 is also very convenient.

[0022] It should be noted that the welding work between the support member 40 and the steel pipe pile unit 11 can be carried out before the waist beam 20 is lifted, or it can be welded after the waist beam 20 is lifted to a specified height.

[0023] As a preferred embodiment, a flange 411 is provided on the edge of the platform 41 away from the steel pipe pile array 10, and the flange 411 extends upward. In this embodiment, the flange 411 at the suspended end edge of the platform 41 can laterally limit the waist beam 20 supported on the platform 41. Before the prestressed cable 30 is tensioned, it helps to prevent the waist beam 20 from slipping off the platform 41 due to accidental circumstances and causing a safety accident.

[0024] As a preferred embodiment, a capping beam 12 is provided at the top of the steel pipe pile array 10. The capping beam 12 extends along the arrangement direction of the individual steel pipe piles 11 and connects to the top of the individual steel pipe piles 11. The capping beam 12 helps to ensure the overall rigidity of the steel pipe pile array 10.

[0025] Combination Figure 2As shown, in order to reinforce the pit wall between two adjacent steel pipe pile units 11, steel reinforcement mesh 50 is sprayed and anchored on the pit wall between two adjacent steel pipe pile units 11 in the steel pipe pile array 10 on the foundation pit A.

[0026] The construction method of this utility model is as follows:

[0027] Step 1: Using a casing drilling rig, steel pipe piles 11 are constructed at intervals along the edge of the designated area of ​​foundation pit A to form a steel pipe pile array 10, and then the earthwork of foundation pit A is excavated.

[0028] Step 2: Drill a cable-passing tunnel B1 through the pit cavity of the two adjacent pits A on the opposite side walls between the two pits A.

[0029] Step 3: Insert prestressed cables 30 into each cable-threading duct B1.

[0030] Step 4: Erect the waist beam 20 on the steel pipe pile array 10.

[0031] Step 5: Insert the two free ends of the prestressed cable 30 into the anchorages 21 on the opposite side waist beams 20 of the two adjacent foundation pits A and tension them. Use jacks to tension and lock them on both sides simultaneously, with a typical locking value between 160-180 kN.

[0032] Specifically, in step one, an air compressor and a casing drill are used to vertically impact and drive the steel pipes constituting the individual steel pipe pile 11 into the ground in sections. Adjacent steel pipes are connected by internal and external threads, which improves construction speed and reduces the space and weight required for workers to operate individual micro-steel pipe piles, making it more responsive. The steel pipe piles are installed at 500mm intervals. Cement grout is injected into the steel pipes, overflowing from the bottom to the sides and enveloping the pipes. Gravel is then filled into the grout, which solidifies to form the pile body concrete. This effectively encapsulates the steel pipe pile with cement grout, increasing its embedment stability and enhancing the overall rigidity and durability of the micro-steel pipe pile.

[0033] After the steel pipe pile array 10 is constructed, a reinforced concrete cap beam 12 is built on top of the steel pipe pile array 10. The cap beam 12 is generally set with a size of 400×600mm, and is equipped with 6 HRB400 steel bars with a diameter of 18mm as longitudinal reinforcing bars, with stirrups set in the middle at 150mm intervals, which can greatly improve the overall lateral stiffness of the steel pipe pile and enhance the overall stress performance of the steel pipe pile.

[0034] After the capping beam 12 is completed and its strength reaches 75% or more, the foundation pit A is excavated and the steel pipe pile array 10 and the individual steel pipe pile 11 are sprayed with steel reinforcement mesh 50.

[0035] When the excavation depth of foundation pit A reaches 3m, a casing drilling rig is used to horizontally drill cable-passing ducts B1 on the opposite side walls of the two adjacent foundation pits A, with a drilling spacing of 2.5m. After step five is completed, the excavation of foundation pit A continues to the designated depth, and cable-passing ducts B1 are drilled horizontally again to pass through the prestressed cables 30, and step five is repeated.

[0036] In step three, the free end of the prestressed cable 30 extends 1.5m beyond the steel pipe piles on both sides, and at the same time, the vent pipe and grouting pipe are inserted into the cable-passing duct B1; after step five is completed, before continuing to excavate the soil of the foundation pit A, cement grout with a water-cement ratio of 1:0.5 is injected through the grouting pipe. When grout flows out of the vent hole, the grouting is stopped, and grouting is replenished again after 30 minutes.

Claims

1. A steel pipe pile foundation pit support, wherein a steel pipe pile array (10) is arranged on the pit wall of the foundation pit (A), the steel pipe pile array (10) includes individual steel pipe piles (11), the individual steel pipe piles (11) are arranged vertically and spaced along the length direction of the pit wall, and the lower end of the individual steel pipe piles (11) extends to the base of the foundation pit (A), and a horizontally arranged waist beam (20) is provided on the pit wall of the foundation pit (A) and the waist beam (20) is arranged parallel to the steel pipe pile array (10), the waist beam (20) is located on the side of the steel pipe pile array (10) near the center of the foundation pit (A), characterized in that: A cable-passing channel (B1) is provided in the soil (B) between the opposite side walls of two adjacent foundation pits (A). The pit cavities of the two foundation pits (A) are connected through the cable-passing channel (B1). The prestressed cable (30) passes through the cable-passing channel (B1) and the two ends of the prestressed cable (30) are respectively connected to the waist beam (20) on the opposite side walls of the two foundation pits (A).

2. The steel pipe pile foundation pit support according to claim 1, characterized in that: The cable-passing channel (B1) is a long straight hole with its core direction in the horizontal direction. The cable-passing channel (B1) is located between two adjacent steel pipe pile units (11) on the steel pipe pile array (10).

3. The steel pipe pile foundation pit support according to claim 2, characterized in that: The cable-passing channels (B1) are arranged at intervals along the length of the waist beam (20) and are respectively set between two adjacent steel pipe pile units (11).

4. The steel pipe pile foundation pit support according to claim 1 or 3, characterized in that: An anchorage (21) is provided on the side of the waist beam (20) away from the steel pipe pile array (10). The free end of the prestressed cable (30) passes through the through hole of the waist beam (20) and the cable hole on the anchorage (21) in sequence and is anchored by the anchorage (21).

5. The steel pipe pile foundation pit support according to claim 4, characterized in that: The waist beam (20) includes two channel steels (22) with their openings facing away from each other and their bottoms facing each other. The two channel steels (22) are arranged in parallel vertically and their ends extend toward the corner of the pit wall (A). The bottoms of the two channel steels (22) are arranged at intervals. The outer walls of the two channel steels (22) near the end of the cable-passing hole (B1) are welded together by steel pads (23). The anchor (21) is set on the steel pad (23) on the side near the center of the pit (A). The free end of the prestressed cable (30) passes through the through hole on the steel pad (23) and the interval between the two channel steels (22) and enters the cable-passing hole on the anchor (21).

6. The steel pipe pile foundation pit support according to claim 1, characterized in that: The steel pipe pile array (10) is provided with a support member (40) on the side near the center of the foundation pit (A). The support member (40) supports the lower end face of the waist beam (20) and restricts the downward displacement of the waist beam (20).

7. The steel pipe pile foundation pit support according to claim 6, characterized in that: The support member (40) includes a flat support platform (41). One end of the support platform (41) adjacent to the steel pipe pile array (10) is connected to a vertically placed and downwardly extending connecting plate (42). The connecting plate (42) is connected to the opposite steel pipe pile unit (11). The outer plate surface of the connecting plate (42) and the lower end surface of the support platform (41) are connected by a plate-shaped reinforcing rib (43) with the plate surface perpendicular to the connecting plate (42) and the lower end surface of the support platform (41). The waist beam (20) is supported on the platform surface of the support platform (41).

8. The steel pipe pile foundation pit support according to claim 7, characterized in that: A flange (411) is provided on the edge of the platform (41) away from the steel pipe pile array (10), and the flange (411) extends upward.

9. The steel pipe pile foundation pit support according to claim 1, characterized in that: The top of the steel pipe pile array (10) is provided with a cap beam (12), which extends along the arrangement direction of the individual steel pipe piles (11) and is connected to the top of the individual steel pipe piles (11).

10. The steel pipe pile foundation pit support according to claim 1, characterized in that: The pit wall of the foundation pit (A) between two adjacent steel pipe pile units (11) in the steel pipe pile array (10) is sprayed with steel mesh (50).

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