Soft soil foundation pit supporting structure, supporting method thereof and lattice steel pipe pile

Abstract

The present application belongs to the field of soft soil foundation pit support, and discloses a soft soil foundation pit support structure, a support method thereof and a lattice steel pipe pile, wherein the soft soil foundation pit support structure is composed of a plurality of lattice steel pipe piles arranged on the soil retaining side; the lattice steel pipe pile is composed of a three-limb strip pile body and a pressing top plate welded on the top of the pile body, a hole is arranged in the middle of the pressing top plate; the lattice steel pipe pile is arranged in one or more rows in all right positions or / and one right one reverse positions on the soil retaining side; and the lattice steel pipe piles on the free side are connected by a plurality of waist beams. The lattice steel pipe pile is used as the support of the soft soil foundation pit, which can greatly shorten the construction period and save the construction cost compared with the conventional rotary digging hole filling support pile, and can improve the lateral stiffness of the support structure, effectively suppress the deformation and increase the safety compared with the steel sheet pile support.

Description

Technical Field

[0001] This invention relates to the field of soft soil foundation pit support, and more particularly to a soft soil foundation pit support structure and support method, and a lattice steel pipe pile. Background Technology

[0002] In engineering construction, it is common to encounter the need to excavate foundation pits on soft soil foundations formed by lake or marine sedimentary deposits. In such cases, if conventional rotary-drilled cast-in-place concrete piles are used, there will be disadvantages such as difficulty in drilling, poor concrete pouring quality (easily leading to necking, mud inclusion, etc.), long construction period, and high cost. If conventional steel sheet piles are used, although the above disadvantages are avoided, the weak lateral stiffness of steel sheet piles often leads to problems such as insufficient safety reserve and large deformation of the foundation pit.

[0003] Therefore, it is necessary to design a pile foundation for soft soil foundation pit support to solve the above-mentioned problems. Summary of the Invention

[0004] The present invention aims to solve the technical problems existing in the prior art. To this end, the present invention provides a soft soil foundation pit support structure and support method, as well as a lattice steel pipe pile.

[0005] The technical solution adopted by this invention to solve its technical problem is:

[0006] A soft soil foundation pit support structure is provided, consisting of multiple lattice steel pipe piles arranged on the retaining side; the lattice steel pipe piles are composed of three-limb strip-type pile bodies and capping plates welded to the top of the pile bodies, and the capping plates have holes in the middle; the lattice steel pipe piles are arranged in one or more rows on the retaining side, either all upright or alternating between upright and reversed; the row of lattice steel pipe piles on the free side is connected together by multiple waist beams.

[0007] A support method for the soft soil foundation pit support structure described above is also provided, which is constructed as follows:

[0008] Several lattice steel pipe piles are arranged in one or more rows on the retaining side at a set interval, either all upright or alternating between upright and reverse.

[0009] The row of lattice steel pipe piles on the free side is connected together by multiple waist beams;

[0010] When multiple rows of lattice steel pipe piles are installed, H-beams are used to weld the capping plates of the multiple rows of lattice steel pipe piles together into a whole.

[0011] After the foundation pit is backfilled, the lattice steel pipe piles will be pulled out and recycled for reuse.

[0012] Preferably, the lattice steel pipe pile is driven into the soil by static pressure or hammering, and a pile cap is installed on the capping plate during pile driving.

[0013] Preferably, after the lattice-type steel pipe pile is implanted into the soil, fine stone concrete can be poured into the holes of the capping plate at the top of the steel pipe pile to enhance the strength of the steel pipe pile.

[0014] The invention also provides a lattice-type steel pipe pile in the soft soil foundation pit support structure, wherein the three-limb laced pile body is composed of three column limbs distributed in an equilateral triangle and multiple laced strips welded between two adjacent column limbs, and the column limbs are connected to the laced strips and the capping plate by a full penetration weld.

[0015] Preferably, the column is made of steel pipe, and a tapered pile tip is welded to the bottom of the steel pipe.

[0016] Preferably, the steel pipe is made of Q235B or Q345B steel, with an outer diameter of 146mm to 245mm and a wall thickness of 6mm to 16mm.

[0017] Preferably, the conical pile tip is made of Q235B steel with a plate thickness of 6mm and a cone angle of 40-60°.

[0018] Preferably, the lacing strip is made of Q235B steel with a thickness of 8-16mm, and the distance between the topmost lacing strip and the top plate does not exceed 200mm.

[0019] Preferably, the aspect ratio of the lacing strip is 1:2 to 1:2.5, and the distance between two adjacent lacing strips is 1 to 2 times the height of the lacing strip.

[0020] Preferably, the capping plate is made of Q235B steel, and its outer contour is an equilateral triangle with corners removed. The holes are contour holes that follow the outer contour of the capping plate.

[0021] Compared with the prior art, the beneficial effects of the present invention are:

[0022] This invention uses lattice steel pipe piles as support for soft soil foundation pits. Compared with conventional rotary drilling and grouting support piles, it can greatly shorten the construction period and save construction costs. Compared with steel sheet pile support, it can improve the lateral stiffness of the support structure, effectively suppress deformation, and increase safety. Attached Figure Description

[0023] To more clearly illustrate the technical solutions in the embodiments of the present invention, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort, wherein:

[0024] Figure 1 This is a plan view of the first embodiment of the soft soil foundation pit support structure provided by the present invention;

[0025] Figure 2 This is a plan view of the second embodiment of the soft soil foundation pit support structure provided by the present invention;

[0026] Figure 3 This is a plan view of the third embodiment of the soft soil foundation pit support structure provided by the present invention;

[0027] Figure 4 This is a structural schematic diagram of the lattice steel pipe pile provided by the present invention;

[0028] Figure 5 yes Figure 4 A top perspective view of the lattice steel pipe pile provided. Detailed Implementation

[0029] It should be understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention.

[0030] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of the present invention, and not all of them. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative effort are within the scope of protection of the present invention.

[0031] In the description of this invention, it should be noted that all directional indicators (such as up, down, left, right, front, back, etc.) in the embodiments of this invention are only used to explain the relative positional relationship and movement of each component in a certain specific posture (as shown in the figure). If the specific posture changes, the directional indicator will also change accordingly.

[0032] Furthermore, the technical solutions of the various embodiments can be combined with each other, but only if they are feasible for those skilled in the art. If the combination of technical solutions is contradictory or cannot be implemented, it should be considered that such combination of technical solutions does not exist and is not within the scope of protection claimed by this invention.

[0033] Example 1

[0034] This embodiment provides a soft soil foundation pit support structure, as shown in the attached figure. Figure 1 To be continued Figure 3 As shown, the support structure is formed by multiple lattice steel pipe piles 1 arranged on the retaining side.

[0035] Preferred options are listed below. Figure 4 and attached Figure 5As shown, the lattice steel pipe pile 1 consists of a three-limbed strip-type pile body 1.1 and a capping plate 1.2 welded to the top of the pile body. The capping plate can make the pile body bear the force evenly when it is driven into the soil, and at the same time strengthen the connection strength of the three columns of the pile body. The capping plate 1.2 has a hole 1.2.0 in the middle to facilitate the pouring of concrete into the pile body and enhance the strength of the pile body.

[0036] In specific implementation, the preferred support methods for the lattice steel pipe piles are as follows:

[0037] First implementation method: as shown in the appendix Figure 1 As shown, the lattice steel pipe piles 1 are all upright in a row on the retaining side.

[0038] Second implementation method: as shown in the appendix Figure 2 As shown, the lattice steel pipe piles 1 are arranged in a row on the retaining side, alternating between positive and negative.

[0039] The third implementation method: as shown in the appendix Figure 3 As shown, the lattice steel pipe piles 1 are arranged in multiple rows on the retaining side, alternating between positive and negative. In the illustrated embodiment, there are two rows, but more than two rows can be set.

[0040] Preferably, the row of lattice steel pipe piles 1 on the free side of the support structure is connected together by multiple waist beams 2.

[0041] The support method for the soft soil foundation pit support structure in this embodiment is as follows:

[0042] Several lattice steel pipe piles are driven into the soil on the retaining side at a set interval according to the actual situation, using the above-described method by static pressure or hammering. During pile driving, pile caps are installed on the capping plate.

[0043] The row of lattice steel pipe piles on the free side is connected together by multiple waist beams;

[0044] When there are multiple rows of lattice steel pipe piles 1, H-beams 3 are used to weld the capping plates 1.2 of the multiple rows of lattice steel pipe piles 1 together into a whole.

[0045] According to the design strength, if necessary, fine stone concrete can be poured into the holes of the capping plate at the top of the steel pipe pile to enhance the strength of the steel pipe pile.

[0046] After the foundation pit is backfilled, the lattice steel pipe piles will be pulled out and recycled for reuse.

[0047] Example 2

[0048] This embodiment provides a lattice-type steel pipe pile as described in Embodiment 1, as shown in the attached figure. Figure 4 and attached Figure 5As shown, the pile body 1.1 of the steel pipe pile 1 consists of three column members 1.1.1 arranged in an equilateral triangle and multiple connecting strips 1.1.2 welded between adjacent column members 1.1.1. The column members 1.1.1 are connected to the connecting strips 1.1.2 and the capping plate 1.2 by full penetration welds. In this embodiment, the steel pipe pile connects the column members into a whole through multiple connecting strips, which not only significantly increases the lateral stiffness of the steel pipe pile.

[0049] Preferably, the column member 1.1.1 is made of steel pipe, which is made of Q235B or Q345B steel, with an outer diameter of 146mm to 245mm and a wall thickness of 6mm to 16mm; a conical pile tip is welded to the bottom of the steel pipe, which is made of Q235B steel, with a plate thickness of 6mm and a cone angle of 40 to 60°. The conical pile tip enables the steel pipe pile to be driven into the soil smoothly.

[0050] Preferably, the lacing strip 1.1.2 is made of Q235B steel with a thickness of 8-16mm, and the distance between the topmost lacing strip 1.1.2 and the top plate 1.2 does not exceed 200mm.

[0051] Preferably, the aspect ratio of the lacing strip 1.1.2 is 1:2 to 1:2.5, and the spacing between two adjacent lacing strips is 1 to 2 times the height of the lacing strip. This design satisfies the lateral stiffness requirements of the steel pipe pile while also meeting the connection strength requirements of the column members.

[0052] Preferably, the capping plate 1.2 is made of Q235B steel, with an outer contour of a truncated equilateral triangle, and the hole 1.2.0 is a contour hole of the outer contour of the capping plate. The capping plate's truncated shape not only reduces steel consumption and saves costs, but also provides a gripping space for the vibratory hammer, facilitating the driving and extraction of steel pipe piles.

[0053] It is worth noting that the lattice steel pipe piles provided by this invention can also be combined with other foundation pit support forms, such as lattice steel pipe piles + upper slope or soil nailing wall, lattice steel pipe piles + internal bracing or diagonal bracing, lattice steel pipe piles + soil reinforcement, lattice steel pipe piles + anchor rods (anchor cables), etc.

[0054] The above description is merely an embodiment of the present invention and does not limit the patent scope of the present invention. Any equivalent structural or procedural transformations made based on the content of the present invention specification, or direct or indirect applications in other related technical fields, are similarly included within the patent protection scope of the present invention.

Claims

1. A soft soil foundation pit support structure, characterized in that: Multiple lattice steel pipe piles are arranged on the retaining side; The lattice-type steel pipe pile consists of a three-limbed strip-jointed pile body and a capping plate welded to the top of the pile body. The capping plate has a hole in the middle. The three-limbed strip-jointed pile body consists of three column legs distributed in an equilateral triangle and multiple strips welded between two adjacent column legs. The column legs are connected to the strips and the capping plate by a full penetration weld. The column legs are made of steel pipes, and a conical pile tip is welded to the bottom of the steel pipes. The lattice steel pipe piles are arranged in multiple rows on the retaining side, alternating between positive and negative orientations. The row of lattice steel pipe piles located on the free side is connected together by multiple waist beams; The support method for the soft soil foundation pit support structure shall be constructed as follows: Several lattice steel pipe piles are arranged in multiple rows on the retaining side with alternating positive and negative orientations according to a set spacing. The row of lattice steel pipe piles on the free side is connected together by multiple waist beams; H-beams are used to weld the capping plates of multiple rows of lattice steel pipe piles together into a whole. After the lattice steel pipe pile is implanted into the soil, fine stone concrete can be poured into the holes of the capping plate at the top of the steel pipe pile to enhance the strength of the lattice steel pipe pile. After the foundation pit is backfilled, the lattice steel pipe piles will be pulled out and recycled for reuse.

2. The soft soil foundation pit support structure according to claim 1, characterized in that: The lattice steel pipe piles are driven into the soil by static pressure or hammering, and pile caps are installed on the capping plate during pile driving.

3. The soft soil foundation pit support structure according to claim 1, characterized in that: The steel pipe is made of Q235B or Q345B steel, with an outer diameter of 146mm~245mm and a wall thickness of 6mm~16mm; the conical pile tip is made of Q235B steel, with a plate thickness of 6mm and a cone angle of 40~60°.

4. The soft soil foundation pit support structure according to claim 1, characterized in that: The lacing strip is made of Q235B steel with a thickness of 8~16mm, and the distance between the topmost lacing strip and the top plate does not exceed 200mm.

5. The soft soil foundation pit support structure according to claim 4, characterized in that: The aspect ratio of the lacing strip is 1:2 to 1:2.5, and the distance between two adjacent lacing strips is 1 to 2 times the height of the lacing strip.

6. The soft soil foundation pit support structure according to claim 1, characterized in that: The capping plate is made of Q235B steel, and its outer contour is an equilateral triangle with corners removed. The holes are contour holes that follow the outer contour of the capping plate.

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