Construction method of internal support lattice stand column pile

Abstract

The invention relates to the field of foundation pit inner support supporting structures, in particular to a construction method of an inner support lattice stand column pile, which comprises the following steps of: pressing a prestressed pipe pile into the ground; and a reinforcement cage is inserted into the pile top of the prestressed pipe pile, the reinforcement cage and the reinforcement framework of the supporting beam are connected into a whole, concrete is poured into the pile top and the mold of the supporting beam at the same time, and after the concrete is solidified, the pile top, the reinforcement cage and the supporting beam are connected into a whole. According to the embodiment of the invention, the prestressed pipe piles are adopted as the inner support lattice stand column piles, the prestressed pipe piles and the support beams are combined into a whole to form the foundation pit inner support supporting structure, and the problems that a traditional steel lattice stand column is low in shearing resistance and bending resistance, rotary excavating equipment needs to be introduced when the steel lattice stand column is built in a foundation pit, and the construction cost is low are solved. And the construction cost and the construction period are increased.

Description

Technical Field

[0001] The invention relates to the field of supporting and supporting structures in foundation pits, and in particular to a construction method for internal supporting lattice column piles. Background Art

[0002] The related technology of the internal support lattice column pile involved in the subject matter disclosed in the present invention is disclosed in: CN105239594B prestressed pipe pile column.

[0003] In the internal supporting structure of the foundation pit, the shear and bending strength of traditional steel lattice columns are low, and it is difficult to cope with the pressure of the soft soil layer and the problems of soil and sand flow caused by the high groundwater level. The construction of steel lattice columns inside the foundation pit requires the introduction of rotary drilling equipment, which increases construction costs and construction period.

[0004] Therefore, people need a lattice column that has high shear and bending strength and can be quickly constructed. Summary of the invention

[0005] The purpose of the present invention is to provide a construction method for internal support lattice column piles to solve the technical problems that traditional steel lattice columns have low shear and bending strength, and that rotary drilling equipment needs to be introduced when constructing steel lattice columns inside a foundation pit, which increases construction costs and construction period.

[0006] In order to solve the above technical problems, the present invention specifically provides the following technical solutions:

[0007] A construction method for an internally supported lattice column pile comprises the following steps: pressing a prestressed pipe pile into the ground; inserting a steel cage into the interior of the pile top of the prestressed pipe pile, wherein the steel cage is connected to a steel skeleton of a support beam as a whole; simultaneously pouring concrete inside the pile top and inside a mold of the support beam; after the concrete solidifies, the pile top, the steel cage and the support beam are connected as a whole.

[0008] Furthermore, before inserting the steel cage into the prestressed pipe pile, a steel plate is used to seal the bottom of the steel cage so that the height of the concrete poured into the prestressed pipe pile is equal to the height of the steel cage.

[0009] Furthermore, the main bars of the steel cage are bent outward horizontally, and after the steel cage is inserted into the interior of the prestressed pipe pile, the main bars are connected to the steel skeleton of the support beam as a whole.

[0010] Furthermore, in the process of pressing the prestressed pipe piles into the ground, two sections of the prestressed pipe piles are connected using a welding process, and a first clamp is installed on the outer side of the prestressed pipe pile to reinforce the welded joint.

[0011] As another embodiment of the present application, during the process of digging the foundation pit, a second clamp is installed at the connection position between the pile body of the prestressed pipe pile and the support beam, and an embedded steel plate surrounding the second clamp is welded on the top of the second clamp, and the anchor bars of the embedded steel plate are connected to the steel skeleton of the support beam as a whole, and then concrete is poured into the inside of the mold of the support beam. After the concrete solidifies, the pile body, the second clamp, the embedded steel plate and the support beam are connected as a whole.

[0012] As another embodiment of the present application, in the process of pressing the prestressed pipe piles into the ground, a section of steel pipe piles is arranged between two sections of the prestressed pipe piles, and the steel pipe piles and the prestressed pipe piles are connected using a welding process, and the total length of each section of the prestressed pipe piles and each section of the steel pipe piles is equal to the floor height between two adjacent layers of the support beams.

[0013] Furthermore, in the process of digging the foundation pit, an embedded steel plate surrounding the steel pipe pile is welded on the top of the steel pipe pile, the anchor bars of the embedded steel plate are connected to the steel frame of the support beam as a whole, and then concrete is poured into the inside of the mold of the support beam. After the concrete solidifies, the steel pipe pile, the embedded steel plate and the support beam are connected as a whole.

[0014] Furthermore, the foundation pit is excavated using a basin-type excavation process, and the prestressed pipe piles are enclosed.

[0015] Furthermore, after the foundation pit is excavated, a second clamp is installed at the connection position between the pile body of the prestressed pipe pile and the raft slab, a rubber water stop is inserted between the second clamp and the prestressed pipe pile, and an embedded steel plate surrounding the second clamp is welded on the top of the second clamp, the anchor bars of the embedded steel plate are connected to the steel skeleton of the raft slab as a whole, and then concrete is poured into the inside of the mold of the raft slab. After the concrete solidifies, the prestressed pipe pile, the second clamp, the rubber water stop, the embedded steel plate and the raft slab are connected as a whole.

[0016] Furthermore, the portion of the prestressed pipe pile that is higher than the raft slab is removed, and the interior of the prestressed pipe pile is filled with anti-seepage concrete, and then a water-stop steel plate is welded on the top of the embedded steel plate to close the through hole in the center of the embedded steel plate.

[0017] Compared with the prior art, this application has the following beneficial effects:

[0018] Provided is a construction method for internal support lattice column piles, which adopts prestressed pipe piles as the internal support lattice column piles, and combines the prestressed pipe piles with support beams to form a supporting structure in a foundation pit, thereby solving the technical problems that the shear and bending strengths of traditional steel lattice columns are low, and rotary drilling equipment needs to be introduced when constructing steel lattice columns inside the foundation pit, which increases the construction cost and construction period. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] In order to more clearly illustrate the implementation methods of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for the implementation methods or the description of the prior art. Obviously, the drawings in the following description are only exemplary, and for ordinary technicians in this field, other implementation drawings can be derived from the provided drawings without creative work.

[0020] Figure 1 It is a front view of the welding structure of two sections of prestressed pipe piles according to the first embodiment of the present invention;

[0021] Figure 2 A top view of a welding structure of two sections of prestressed pipe piles according to a first embodiment of the present invention;

[0022] Figure 3 A cross-sectional view of a connection structure between a pile top and a support beam of a prestressed pipe pile according to a first embodiment of the present invention;

[0023] Figure 4 It is a schematic diagram of the position of the connection structure of the pile top and the support beam of the prestressed pipe pile of the first embodiment of the present invention inside the foundation pit;

[0024] Figure 5 It is a schematic diagram of the position of the connection structure of the prestressed pipe pile, the support beam and the raft slab in the foundation pit according to the first embodiment of the present invention;

[0025] Figure 6 A cross-sectional view of a connection structure between a pile body and a raft slab of a prestressed pipe pile according to a first embodiment of the present invention;

[0026] Figure 7 for Figure 6 Cross-sectional view in the AA direction;

[0027] Figure 8 A cross-sectional view of a connection structure of a steel pipe pile and a support beam according to a second embodiment of the present invention;

[0028] Fig. 9 It is a schematic diagram of the position of the connection structure of the prestressed pipe piles, steel pipe piles, support beams and raft slabs in the foundation pit according to the second embodiment of the present invention;

[0029] The numbers in the figure represent the following:

[0030] 1-foundation pit; 11-raft slab; 2-support beam; 3-column pile; 31-prestressed pipe pile; 32-weld; 33-first clamp; 34-second clamp; 35-bolt; 36-steel pipe pile; 37-pin column; 38-pipe plug; 4-rebar cage; 41-main reinforcement; 42-steel plate; 5-embedded steel plate; 51-anchor reinforcement; 6-rubber waterstop; 7-waterstop steel plate. DETAILED DESCRIPTION

[0031] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0032] (First embodiment)

[0033] The following provides a construction method for an internally supported lattice column pile, comprising the following steps:

[0034] Step 1: Construction preparation: Conduct a detailed on-site survey to understand the geological conditions and groundwater level, arrange the construction site according to the design requirements, determine the pile position and perform line-laying and calibration, prepare construction materials such as prestressed pipe piles 31, steel cage 4, concrete, embedded steel plates 5, rubber water stop 6, first clamp 33, second clamp 34, etc., and ensure that the material quality meets the requirements.

[0035] Step 2: Install the prestressed pipe pile 31: Lift the prestressed pipe pile 31 of specification HPC-600-C-130, align the pile tip vertically with the center of the pile position, first insert the prestressed pipe pile 31 30cm to 50cm underground with the deadweight of the pile hammer, then stabilize the prestressed pipe pile 31 vertically, and then press the prestressed pipe pile 31 into the ground with a static pile driver.

[0036] Step 3: Connect prestressed pipe pile 31: Figure 1 , Figure 2 When the length of the prestressed pipe pile 31 is insufficient, a welding process is used to connect the two sections of the prestressed pipe pile 31. The height of the weld 32 is not less than 10 mm. The outer side of the weld 32 is reinforced with a first clamp 33. The height of the first clamp 33 is not less than 500 mm. The first clamp 33 is installed with a 10.9-grade M30 high-strength bolt 35. The preload force of each bolt 35 is 355 KN, which ensures the strength and sealing of the joint between the two sections of the prestressed pipe pile 31.

[0037] Step 4: Connect the top of the prestressed pipe pile 31 and the support beam 2: Figure 3A prefabricated steel cage 4 is inserted into the inside of the pile top. The diameter of the steel cage 4 is 300 mm. The bottom of the steel cage 4 is closed by a steel plate 42 with a diameter of 310 mm. The main reinforcement 41 of the steel cage 4 is 3800 mm long. The top of the main reinforcement 41 of the steel cage 4 is bent outward so that the main reinforcement 41 of the steel cage 4 extends outward horizontally by 800 mm. The main reinforcement 41 of the horizontally extended steel cage 4 is connected to the steel skeleton of the support beam 2 as a whole. The two are fixed by binding or welding, and then concrete is poured simultaneously inside the prestressed pipe pile 31 and inside the mold of the support beam 2. The concrete will be filled inside the prestressed pipe pile 31 and inside the mold of the support beam 2.

[0038] Step 5: Excavation of underground space: Combination Figure 4 After the concrete solidifies, the prestressed pipe pile 31 and the support beam 2 are firmly connected as a whole to form an integral internal support structure, wherein the concrete inserted into the interior of the prestressed pipe pile 31 and the steel cage 4 form a pin column 37, which can prevent rainwater from entering the interior of the prestressed pipe pile 31.

[0039] Then, an excavator is used to dig out an underground space between the prestressed pipe pile 31 and the support beam 2. It should be noted that the earth excavation process needs to adopt a basin excavation process, and the prestressed pipe pile 31 is surrounded within a range of 1m to prevent the excavator from colliding with the prestressed pipe pile 31.

[0040] Step 6: Connect the prestressed piles 31 and the raft 11: Figure 5 A second clamp 34 is installed at the connection position between the prestressed pipe pile 31 and the raft 11. The first clamp 33 and the second clamp 34 have the same specifications. A 20mm thick rubber water stop sheet 6 is inserted between the second clamp 34 and the prestressed pipe pile 31. A 1000mm×1000mm embedded steel plate 5 is welded on the top of the second clamp 34. The center of the embedded steel plate 5 has a through hole for avoiding the pile body. The diameter of the through hole is greater than 600mm and less than 650mm. An anchor bar 51 with a diameter of 20mm and a length of 800mm is welded at the bottom of the embedded steel plate 5. The anchor bar 51 is connected to the steel skeleton of the raft 11 as a whole. The two are fixed by binding or welding, and then concrete is poured into the inside of the mold of the raft 11. After the concrete solidifies, the prestressed pipe pile 31, the second clamp 34, the rubber water stop sheet 6, the embedded steel plate 5 and the raft 11 are firmly connected as a whole.

[0041] Step 7: Remove support beam 2: Combine Figure 6 , Figure 7According to the design requirements, the basement is built layer by layer from bottom to top and the supporting beam 2 is removed. At the same time, the part of the redundant prestressed pipe piles 31 that is higher than the raft 11 is removed, and then the cut is trimmed and leveled. P8 anti-seepage fine stone concrete is filled inside the prestressed pipe piles 31, and the filling height is 5 meters. Then, a water-stop steel plate 7 is welded on the top of the embedded steel plate 5 to close the through hole in the center of the embedded steel plate 5. The water-stop steel plate 7 is a circular shape with a diameter of 650 mm. Finally, fine stone concrete is filled above the water-stop steel plate 7 to make the surface of the raft 11 smooth. Among them, the concrete filled into the interior of the prestressed pipe piles 31 forms a pipe plug 38, which can prevent groundwater from leaving the interior of the prestressed pipe piles 31.

[0042] When the inner support foundation pit support structure has two or more layers of support beams 2, step 4 also includes connecting the pile body of the prestressed pipe pile 31 and the support beam 2: Figure 8 A second hoop 34 is installed at the connection between the pile body and the support beam 2, and the embedded steel plate 5 is welded on the top of the second hoop 34. The anchor bars 51 of the embedded steel plate 5 are connected to the steel frame of the support beam 2 as a whole. The two are fixed by binding or welding, and then concrete is poured into the inside of the mold of the support beam 2. After the concrete solidifies, the pile body, the second hoop 34, the embedded steel plate 5 and the support beam 2 are firmly connected as a whole.

[0043] (Second embodiment)

[0044] Compared with the technical means of using a prefabricated steel cage 4 to connect the prestressed pipe pile 31 and the support beam 2 into one, the bonding strength between the second clamp 34 and the prestressed pipe pile 31 is weaker. When the depth of the foundation pit 1 is large and the weight of the support beam 2 is heavy, the second clamp 34 is at risk of sliding down from the pile body of the prestressed pipe pile 31.

[0045] In order to solve this problem, the following measures may be taken: instead of using the second clamp 34 , the embedded steel plate 5 may be directly welded to the pile body of the prestressed pipe pile 31 , thereby increasing the bonding strength between the prestressed pipe pile 31 and the support beam 2 .

[0046] Specifically, except for the first and second prestressed pipe piles 31, which are 15 meters in length, the other prestressed pipe piles 31 are 3 to 6 meters in length. Each prestressed pipe pile 31 is connected by a steel pipe pile 36. The total length of each section of prestressed pipe pile 31 and each section of steel pipe pile 36 is equal to the floor height of the support beam 2. The outer diameter of the steel pipe pile 36 is the same as the outer diameter of the prestressed pipe pile 31, both of which are 600 mm. The specific length of the steel pipe pile 36 is less than or equal to the thickness of the support beam 2. The embedded steel plate 5 is welded to the steel pipe pile 36.

[0047] The specific steps of connecting the support beam 2 to the steel pipe pile 36 are: welding the embedded steel plate 5 around the steel pipe pile 36, using a binding or welding process to connect the anchor bar 51 of the embedded steel plate 5 and the steel frame of the support beam 2, and then pouring concrete into the mold of the support beam 2. After the concrete solidifies, the steel pipe pile 36, the embedded steel plate 5 and the support beam 2 are combined into one.

[0048] In addition, the second clamp 34 may not be used, but the embedded steel plate 5 may be directly welded to the pile body of the prestressed pipe pile 31 , thereby improving the bonding strength between the prestressed pipe pile 31 and the raft 11 .

[0049] The specific steps of connecting the raft 11 to the steel pipe piles 36 are: welding the embedded steel plate 5 around the steel pipe piles 36, using a binding or welding process to connect the anchor bars 51 of the embedded steel plate 5 and the steel frame of the raft 11, and then pouring concrete into the mold of the support beam 2. After the concrete solidifies, the steel pipe piles 36, the embedded steel plate 5 and the raft 11 are combined into one, and there is no need to use a rubber water stop 6.

[0050] It should be emphasized that the specifications of the prestressed pipe piles 31, the dimensions of the steel pipe piles 36, the dimensions of the support beams 2, and the dimensions of the embedded steel plates 5 in the first and second embodiments are only examples, and their specific dimensions should be designed and selected according to site conditions.

[0051] The above embodiments are only exemplary embodiments of the present invention and are not intended to limit the present invention. The protection scope of the present invention is defined by the claims. Those skilled in the art may make various modifications or equivalent substitutions to the present invention within the essence and protection scope of the present invention, and such modifications or equivalent substitutions shall also be deemed to fall within the protection scope of the present invention.

Claims

1. A construction method for internal support lattice column piles, characterized in that: The steps include: Pressing the prestressed pipe pile (31) into the ground; A steel cage (4) is inserted into the interior of the pile top of the prestressed pipe pile (31), the steel cage (4) is connected to the steel skeleton of the support beam (2) as a whole, concrete is poured simultaneously inside the pile top and inside the mold of the support beam (2), and after the concrete solidifies, the pile top, the steel cage (4) and the support beam (2) are connected as a whole.

2. The construction method of an internal support lattice column pile according to claim 1, characterized in that: Before inserting the steel cage (4) into the prestressed pipe pile (31), a steel plate (42) is used to seal the bottom of the steel cage (4) so ​​that the height of the concrete poured into the prestressed pipe pile (31) is equal to the height of the steel cage (4).

3. The construction method of the internal support lattice column pile according to claim 1, characterized in that: The main reinforcement (41) of the reinforcement cage (4) is bent outward horizontally, and after the reinforcement cage (4) is inserted into the interior of the prestressed pipe pile (31), the main reinforcement (41) is connected to the reinforcement skeleton of the support beam (2) as a whole.

4. The construction method of the internal support lattice column pile according to claim 1, characterized in that: During the process of pressing the prestressed pipe pile (31) into the ground, two sections of the prestressed pipe pile (31) are connected using a welding process, and a first clamp (33) is installed on the outside of the prestressed pipe pile (31) to reinforce the welded joint.

5. The construction method of the internal support lattice column pile according to claim 4, characterized in that: During the process of excavating the foundation pit (1), a second clamp (34) is installed at the connection position between the pile body of the prestressed pipe pile (31) and the support beam (2), and an embedded steel plate (5) surrounding the second clamp (34) is welded on the top of the second clamp (34), and the anchor bars (51) of the embedded steel plate (5) are connected to the steel skeleton of the support beam (2) as a whole, and then concrete is poured into the mold of the support beam (2). After the concrete solidifies, the pile body, the second clamp (34), the embedded steel plate (5) and the support beam (2) are connected as a whole.

6. The construction method of the internal support lattice column pile according to claim 1, characterized in that: During the process of pressing the prestressed pipe piles (31) into the ground, a section of steel pipe piles (36) is arranged between two sections of the prestressed pipe piles (31), and the steel pipe piles (36) and the prestressed pipe piles (31) are connected by welding, wherein the total length of each section of the prestressed pipe piles (31) and each section of the steel pipe piles (36) is equal to the height between two adjacent layers of the support beams (2).

7. A construction method for internal support lattice column piles according to claim 6, characterized in that: During the excavation of the foundation pit (1), a pre-buried steel plate (5) surrounding the steel pipe pile (36) is welded to the top of the steel pipe pile (36), and the anchor bars (51) of the pre-buried steel plate (5) are connected to the steel frame of the support beam (2) as a whole. Then, concrete is poured into the mold of the support beam (2). After the concrete solidifies, the steel pipe pile (36), the pre-buried steel plate (5) and the support beam (2) are connected as a whole.

8. A construction method for internal support lattice column piles according to claim 5 or 7, characterized in that: The foundation pit (1) is excavated using a basin-type excavation process, and the prestressed pipe piles (31) are enclosed and protected.

9. The construction method of the internal support lattice column pile according to claim 1, characterized in that: After the excavation of the foundation pit (1) is completed, a second clamp (34) is installed at the connection position between the pile body of the prestressed pipe pile (31) and the raft (11), a rubber waterproofing sheet (6) is inserted between the second clamp (34) and the prestressed pipe pile (31), and an embedded steel plate (5) surrounding the second clamp (34) is welded on the top of the second clamp (34), and the anchor bar (51) of the embedded steel plate (5) is connected to the steel skeleton of the raft (11) as a whole, and then concrete is poured into the inside of the mold of the raft (11). After the concrete solidifies, the prestressed pipe pile (31), the second clamp (34), the rubber waterproofing sheet (6), the embedded steel plate (5) and the raft (11) are connected as a whole.

10. The construction method of the internal support lattice column pile according to claim 9, characterized in that: The portion of the prestressed pipe pile (31) that is higher than the raft (11) is removed, and the interior of the prestressed pipe pile (31) is filled with anti-seepage concrete, and then a water-stop steel plate (7) is welded on the top of the embedded steel plate (5) to close the through hole in the center of the embedded steel plate (5).

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