A steel pipe pile structure with an expanded bottom and a construction method thereof

Abstract

The application is a kind of expanded bottom steel pipe pile structure and its construction method, which comprises a steel pipe pile, a plurality of stiffening plates welded on the outer side of the lower part of the steel pipe pile, a bottom sealing plate welded on the bottom of the steel pipe pile, a plurality of expanded bottom flange plates arranged along the circumference of the steel pipe pile at the bottom of the steel pipe pile, a hinge connection between the expanded bottom flange plate and the steel pipe pile, a conical sleeve installed below the expanded bottom flange plate, a grouting pipe installed inside the steel pipe pile, a grouting device connected above the grouting pipe, and an air bag connected at the bottom of the grouting pipe. The application significantly improves the vertical bearing capacity of the whole steel pipe pile, effectively reduces the length of the steel pipe pile, does not need large equipment, is simple to operate, and is convenient and fast to construct. The air bag grouting ensures the reliability of the grouting range and grouting effect, guarantees the integrity of the steel pipe pile, and greatly reduces the engineering cost. The application guarantees the effectiveness and safety of the side friction resistance of the steel pipe pile.

Description

TECHNICAL FIELD

[0001] The present application relates to the civil engineering construction technical field, and particularly relates to a bottom-expanded steel pipe pile structure and a construction method thereof. BACKGROUND

[0002] In civil engineering construction projects, steel pipe piles are widely used in lower bearing structures due to their light weight, large rigidity, high bearing capacity, easy adjustment of pile length, convenient transportation and fast construction speed. When the steel pipe piles are used for temporary structures, the steel pipe piles are usually removed after construction to avoid affecting subsequent projects and the environment, and to realize recycling of materials. The counterforce provided by the steel pipe pile as a lower bearing structure includes pile side friction and pile end resistance. The pile end resistance is related to the pile end area and the geological parameters of the soil layer at the pile end. To increase the pile end resistance, the pile diameter or the bearing capacity of the soil layer at the pile end can be increased.

[0003] The existing technologies and their main problems are as follows:

[0004] 1. A concrete block is formed at the bottom of the steel pipe pile by grouting to increase the bearing capacity of the soil layer at the pile end. However, this method cannot guarantee the grouting range and grouting effect, and the pile end area is not increased, so the bearing capacity is limited.

[0005] 2. The pipe wall at the bottom of the steel pipe pile is forced to expand outward by a machine to increase the pile end area and thus increase the bearing capacity. However, this method has the following main problems: the circumferential rigidity of the steel pipe pile is very large, so it is difficult to force the steel pipe pile to expand; the expansion range is limited, so the increase in the pile end bearing capacity is small; the structure of the steel pipe pile is damaged after expansion, so the bearing capacity calculated according to the specification cannot be guaranteed; the steel pipe pile cannot be restored after expansion, so it is difficult to remove and recycle.

[0006] 3. An enlarged head device is added at the bottom of the steel pipe pile. However, the diameter of the enlarged head is much larger than that of the normal part of the steel pipe pile, so the cylindrical soil cavity formed from top to bottom during the driving of the steel pipe pile is also larger than the steel pipe pile, resulting in a gap between the outer wall of the steel pipe pile and the soil, which completely loses the pile side friction, and the bearing capacity is provided only by the pile end resistance, which is greatly reduced. In addition, the enlarged head is easily collapsed during driving due to disturbance of the surrounding soil. SUMMARY

[0007] The present application aims to solve the problems of the prior art and provides a bottom-expanded steel pipe pile structure and a construction method thereof.

[0008] To achieve the above objectives, the present invention adopts the following technical solution: an expanded-base steel pipe pile structure, comprising a steel pipe pile, a plurality of stiffening plates welded to the lower outer side of the steel pipe pile, a bottom sealing plate welded to the bottom of the steel pipe pile, a plurality of expanded-base wing plates arranged circumferentially along the bottom of the steel pipe pile, the expanded-base wing plates being connected to the steel pipe pile by hinges, a conical sleeve installed below the expanded-base wing plates, a grouting pipe installed inside the steel pipe pile, the upper part of the grouting pipe being connected to grouting equipment, and an air bladder being connected to the bottom of the grouting pipe.

[0009] Furthermore, the bottom sealing plate has a grouting hole at its center, the top surface of which is connected to the grouting pipe, and the bottom surface of which is connected to the airbag.

[0010] Furthermore, an annular positioning ring is welded to the bottom of the bottom sealing plate, and the outer diameter of the positioning ring is equal to the inner diameter of the cylinder formed by the positioning plate inside the conical sleeve.

[0011] Furthermore, the hinge includes two upper ear plates, one lower ear plate, and one pin. The upper and lower ear plates are provided with pin holes at corresponding positions. The upper ear plates are welded to the outer side of the bottom of the steel pipe pile, and the lower ear plate is welded to the outer side of the top of the expanded bottom wing plate.

[0012] Furthermore, each expanded bottom flange is connected to the steel pipe pile by two hinges, which are symmetrically arranged on both sides of the stiffening plate.

[0013] Furthermore, the conical sleeve includes an annular steel plate, an upper base plate welded to the bottom of the annular steel plate, a conical steel plate welded to the bottom of the upper base plate, a lower base plate welded to the bottom of the conical steel plate, several positioning plates installed on the inner side of the annular steel plate, the positioning plates welded to the top of the upper base plate, and an expanded bottom wing plate inserted between the positioning plates and the annular steel plate.

[0014] Furthermore, the distance between the positioning plate and the annular steel plate is equal to the thickness of the expanded bottom wing plate.

[0015] Furthermore, the inner diameter of the annular steel plate is equal to the outer diameter of the steel pipe pile.

[0016] Furthermore, the positioning plate is a rectangular steel plate, the height of the positioning plate is greater than the length of the bottom wing plate, and the top of the positioning plate is tightly pressed against the bottom sealing plate.

[0017] Furthermore, the number of stiffening plates and positioning plates is the same as the number of expanded bottom wing plates, and the stiffening plates and positioning plates correspond one-to-one and are located in the middle of the expanded bottom wing plates.

[0018] Furthermore, the diameter of the lower base plate is smaller than the diameter of the upper base plate.

[0019] Furthermore, the expanded bottom flange is an arc-shaped steel plate with the same diameter as the cross-sectional diameter of the steel pipe pile, and its length is between the radius and diameter of the steel pipe pile.

[0020] Furthermore, the length of the bottom edge of the stiffening plate is the same as the length of the expanded bottom flange.

[0021] Furthermore, the expanded-base steel pipe pile structure of the present invention is suitable for soft soil areas with soils mainly composed of silt, silty soil, silty clay, silty clay, etc.

[0022] A construction method for an enlarged-base steel pipe pile structure includes the following steps:

[0023] The first step is to install or weld the expanded bottom flange, hinge, stiffening plate, conical sleeve, airbag, and grouting pipe at the lower end of the steel pipe pile.

[0024] The second step is to use piling machinery to drive the prefabricated steel pipe piles into the soil and reach the designed position.

[0025] The third step is to prepare cement mortar and begin injecting it into the airbag using grouting equipment.

[0026] Fourth step: During grouting, pay attention to the changes in grouting pressure. As the grouting pressure gradually increases, the air bladder expands and pushes the conical sleeve downward away from the expanding wing plate. When the conical sleeve is completely separated from the expanding wing plate, the grouting pressure drops slightly. Continue grouting and stop pressurizing until the grouting pressure stabilizes.

[0027] Fifth step: After the grouting pressure stabilizes, continue to increase the grouting pressure to make the airbag expand in all directions, forcing the bottom expansion wing plate to rotate around the hinge until the bottom expansion wing plate reaches the final position and is tightly attached to the stiffening plate.

[0028] The sixth step is to stop grouting and seal the grouting pipe. Wait for the cement mortar inside the airbag to solidify to complete the steel pipe pile construction.

[0029] The beneficial effects of this invention are as follows: This invention significantly improves the overall vertical bearing capacity of steel pipe piles and effectively reduces the pile length; the hinged-type expanded-base flange can be expanded by grouting, requiring no large equipment, making operation simple, construction convenient and quick, and the air-bag grouting ensures the reliability of the grouting range and effect; this invention will not cause any damage to the original steel pipe pile, ensuring the integrity of the steel pipe pile, and the steel pipe pile can be recycled, significantly reducing project costs; it also ensures the effectiveness and safety of the side friction resistance of the steel pipe pile. Attached Figure Description

[0030] Figure 1 This is a schematic diagram of the structure of the present invention;

[0031] Figure 2 This is a cross-sectional view of the present invention before it is driven into the soil;

[0032] Figure 3 This is a cross-sectional view of the conical sleeve of the present invention when it is disengaged;

[0033] Figure 4 This is a cross-sectional view of the present invention after grouting is completed;

[0034] Figure 5 This is a schematic diagram of the plan view before the present invention is driven into the soil;

[0035] Figure 6 This is a plan view after the grouting of the present invention is completed;

[0036] Figure 7 This is a detailed cross-sectional view of the pile tip portion of the present invention;

[0037] Figure 8 This is a plan view of the hinge structure of the present invention;

[0038] Figure 9 This is an elevation view of the hinge structure of the present invention;

[0039] In the diagram: 1-Steel pipe pile; 11-Bottom sealing plate; 12-Grouting hole; 13-Positioning clasp; 2-Expanded bottom flange; 3-Hinge; 31-Upper ear plate; 32-Lower ear plate; 33-Pin hole; 34-Pin; 4-Stiffening plate; 5-Conical sleeve; 51-Annular steel plate; 52-Positioning clasp; 53-Conical steel plate; 54-Upper bottom plate; 55-Lower bottom plate; 6-Airbag; 7-Cement mortar; 8-Grouting pipe; 9-Grouting equipment; 10-Soil.

[0040] The following will describe in detail, with reference to the accompanying drawings, embodiments of the present invention. Detailed Implementation

[0041] The present invention will be further described below with reference to embodiments:

[0042] like Figures 1-9As shown, an expanded-base steel pipe pile structure includes a steel pipe pile 1. A bottom sealing plate 11 is welded to the bottom of the steel pipe pile 1. A positioning ring 13 is welded to the bottom of the bottom sealing plate. An air bladder 6 is connected to the bottom of the bottom sealing plate 11. The air bladder 6 can withstand a large pressure and expands as the internal pressure increases. Several expanded-base wing plates 2 are arranged in a ring around the outside of the steel pipe pile 1. The steel pipe pile 1 and the expanded-base wing plates 2 are connected by hinges 3. The hinge 3 includes two upper ear plates 31, one lower ear plate 32 and one pin 34. Pin holes 33 are provided at corresponding positions on the upper ear plates 31 and the lower ear plates 32. The upper ear plates 31 are welded to the outside of the bottom of the steel pipe pile 1, and the lower ear plates 32 are welded to the outside of the top of the expanded-base wing plates 2. Each expanded-base wing plate 2 is connected to the steel pipe pile 1 by two hinges 3. The two hinges 3 are symmetrically arranged on both sides of the stiffening plate 4. The expanded base flange 2 can rotate freely around the hinge 3 under pressure. The outward expansion of the expanded base flange 2 increases the bottom area of ​​the steel pipe pile 1 by more than four times. At the same time, the air-filled concrete body 6 formed after solidification is much greater than the bearing capacity of the original soil layer at the pile bottom, which significantly improves the overall vertical bearing capacity of the steel pipe pile 1. Moreover, the expanded base flange 2 connected by the hinge 3 will not cause the problem of difficulty in pulling out the steel pipe pile 1, making the steel pipe pile 1 recyclable. Several stiffening plates 4 are welded to the lower outer side of the steel pipe pile 1. The positions of the stiffening plates 4 correspond one-to-one with the expanded base flange 2. The bottom of the stiffening plates 4 is in close contact with the expanded base flange 2 when it has rotated to its final position and restricts the expanded base flange 2 from continuing to rotate. A conical sleeve 5 is installed below the expanded bottom wing plate 2. The conical sleeve 5 includes an annular steel plate 51. The inner diameter of the annular steel plate 51 is equal to the outer diameter of the steel pipe pile 1. An upper bottom plate 54 is welded to the bottom of the annular steel plate 51. A conical steel plate 53 is welded to the bottom of the upper bottom plate 54. A lower bottom plate 55 is welded to the bottom of the conical steel plate 53. The diameter of the lower bottom plate 55 is smaller than that of the upper bottom plate 54. Several positioning plates 52 are installed on the inner side of the annular steel plate 51. The positioning plates 52 are welded to the top of the upper bottom plate 54. The positioning plates 52 are rectangular steel plates. The height of the positioning plates is greater than the length of the expanded bottom wing plate. The top of the positioning plates is tightly pressed against the bottom sealing plate. A conical sleeve 5 is fitted over a positioning ring 13. The outer diameter of the positioning ring 13 is equal to the inner diameter of the cylinder formed by the positioning plate 52 inside the conical sleeve 5. An expanded bottom flange 2 is inserted between the positioning plate 52 and the annular steel plate 51, with the distance between them equal to the thickness of the expanded bottom flange 2. During the driving of the expanded bottom pile, the downward load is transmitted to the conical sleeve 5 through the positioning plate 52. The conical sleeve 5 is restricted by the positioning ring 13 to prevent lateral displacement, thus protecting the expanded bottom flange 2 inserted between the positioning plate 52 and the annular steel plate 51. A grouting pipe 8 is installed inside the steel pipe pile 1. The bottom of the grouting pipe 8 is connected to the bottom sealing plate 11, and the top of the grouting pipe 8 is connected to a grouting device 9. The grouting device 9 is used for the preparation and injection of cement mortar 7, and the grouting pressure can be adjusted through the grouting device 9. The bottom sealing plate 11 has a grouting hole 12 at its center. The top surface of the grouting hole 12 is connected to the grouting pipe 8, and the bottom surface of the grouting hole 12 is connected to the airbag 6. The number of stiffening plates 4 and positioning plates 52 is the same as the number of bottom wing plates 2.The expanded bottom flange 2 is an arc-shaped steel plate with the same diameter as the cross-sectional diameter of the steel pipe pile 1, and its length lies between the radius and diameter of the steel pipe pile 1. The bottom edge length of the stiffening plate 4 is the same as the length of the expanded bottom flange 2. Cement mortar 7 is injected into the airbag 6 by the grouting equipment 9. As the cement mortar 7 is injected, the airbag 6 expands, pushing the conical sleeve 5 away from the expanded bottom flange 2 and forcing the expanded bottom flange 2 to rotate around the hinge 3 to its final position, ultimately forming a concrete body at the bottom of the steel pipe pile 1 with a diameter larger than the outer diameter of the expanded bottom flange 2 after unfolding.

[0043] A construction method for an enlarged-base steel pipe pile structure includes the following steps:

[0044] The first step is to install or weld the following components to the lower end of the steel pipe pile 1: 2, expanded bottom flange, 3, stiffening plate, 4, tapered sleeve, 5, airbag, 6, and 8.

[0045] The second step is to use pile driving machinery to drive the prefabricated steel pipe pile 1 into the soil layer 10 and reach the designed position.

[0046] The third step is to prepare cement mortar 7 and start injecting grout into the airbag 6 using grouting equipment 9.

[0047] Fourth step: During grouting, pay attention to the changes in grouting pressure. As the grouting pressure gradually increases, the airbag 6 expands and pushes the conical sleeve 5 downward away from the expanding wing plate 2. When the conical sleeve 5 is completely separated from the expanding wing plate 2, the grouting pressure drops slightly. Continue grouting and stop pressurizing until the grouting pressure stabilizes.

[0048] Fifth step: After the grouting pressure stabilizes, continue to increase the grouting pressure to make the airbag 6 expand in all directions, forcing the bottom wing plate 2 to rotate around the hinge 3 until the bottom wing plate 2 reaches the final position and is tightly attached to the stiffening plate 4.

[0049] Step 6: Stop grouting and seal the grouting pipe 8. Wait for the cement mortar 7 inside the airbag 6 to solidify, and the construction of the steel pipe pile 1 will be completed.

[0050] The present invention has been described above by way of example. Obviously, the specific implementation of the present invention is not limited to the above-described manner. Any improvements made by adopting the inventive concept and technical solution of the present invention, or direct application to other occasions without modification, are all within the protection scope of the present invention.

Claims

1. A type of expanded-base steel pipe pile structure, characterized in that, The system includes a steel pipe pile (1), with several stiffening plates (4) welded to the lower outer side of the steel pipe pile (1), a bottom sealing plate (11) welded to the bottom of the steel pipe pile (1), several expanding wing plates (2) arranged circumferentially around the bottom of the steel pipe pile (1), the expanding wing plates (2) and the steel pipe pile (1) are connected by hinges (3), a conical sleeve (5) is installed below the expanding wing plates (2), a grouting pipe (8) is installed inside the steel pipe pile (1), the grouting pipe (8) is connected to the grouting equipment (9) at the top, and an airbag (6) is connected to the bottom of the grouting pipe (8). The bottom sealing plate (11) has a grouting hole (12) in the center. The top surface of the grouting hole (12) is connected to the grouting pipe (8), and the bottom surface of the grouting hole (12) is connected to the airbag (6). The bottom of the bottom sealing plate (11) is welded with an annular positioning ring (13). The outer diameter of the positioning ring (13) is equal to the inner diameter of the cylinder formed by the positioning plate (52) inside the conical sleeve (5). The conical sleeve (5) includes an annular steel plate (51), an upper base plate (54) is welded to the bottom of the annular steel plate (51), a conical steel plate (53) is welded to the bottom of the upper base plate (54), a lower base plate (55) is welded to the bottom of the conical steel plate (53), several positioning plates (52) are installed on the inner side of the annular steel plate (51), the positioning plates (52) are welded to the top of the upper base plate (54), and the expanded bottom wing plate (2) is inserted between the positioning plates (52) and the annular steel plate (51).

2. The expanded-base steel pipe pile structure according to claim 1, characterized in that, The hinge (3) includes two upper ear plates (31), one lower ear plate (32) and one pin (34). The upper ear plate (31) and the lower ear plate (32) are provided with pin holes (33) at corresponding positions. The upper ear plate (31) is welded to the outer side of the bottom of the steel pipe pile (1), and the lower ear plate (32) is welded to the outer side of the top of the expanded bottom wing plate (2).

3. The expanded-base steel pipe pile structure according to claim 2, characterized in that, Each expanded bottom flange (2) is connected to the steel pipe pile (1) by two hinges (3), and the two hinges (3) are symmetrically arranged on both sides of the stiffening plate (4).

4. The expanded-base steel pipe pile structure according to claim 3, characterized in that, The positioning plate (52) is a rectangular steel plate. The height of the positioning plate (52) is greater than the length of the bottom wing plate (2). The top of the positioning plate (52) is pressed against the bottom sealing plate (11). The distance between the positioning plate (52) and the annular steel plate (51) is equal to the thickness of the bottom wing plate (2). The inner diameter of the annular steel plate (51) is equal to the outer diameter of the steel pipe pile (1).

5. The expanded-base steel pipe pile structure according to claim 4, characterized in that, The number of stiffening plates (4) and positioning plates (52) is the same as the number of bottom wing plates (2). The length of the bottom edge of the stiffening plate (4) is the same as the length of the bottom wing plate (2). The stiffening plate (4) and the positioning plates (52) correspond one-to-one and are located in the middle of the bottom wing plate (2).

6. The expanded-base steel pipe pile structure according to claim 5, characterized in that, The expanded bottom wing plate (2) is an arc-shaped steel plate with the same diameter as the cross-sectional diameter of the steel pipe pile (1) and a length between the radius and diameter of the steel pipe pile (1).

7. A construction method for an expanded-base steel pipe pile structure according to claim 6, characterized in that, Includes the following steps: The first step is to install or weld the expanded bottom flange (2), hinge (3), stiffening plate (4), conical sleeve (5), airbag (6), and grouting pipe (8) at the lower end of the steel pipe pile (1); The second step is to use piling machinery to drive the prefabricated steel pipe piles (1) into the soil layer (10) and reach the designed position; The third step is to prepare cement mortar (7) and use grouting equipment (9) to start grouting into the airbag (6); Fourth step: During grouting, pay attention to the changes in grouting pressure. As the grouting pressure gradually increases, the air bladder (6) expands and pushes the conical sleeve (5) downward away from the bottom wing plate (2). When the conical sleeve (5) is completely separated from the bottom wing plate (2), the grouting pressure drops slightly. Continue grouting and stop pressurizing until the grouting pressure stabilizes. Fifth step: After the grouting pressure stabilizes, continue to increase the grouting pressure to make the airbag (6) expand in all directions, forcing the bottom wing plate (2) to rotate around the hinge (3) until the bottom wing plate (2) reaches the final position and is tightly attached to the stiffening plate (4); Step 6: Stop grouting and seal the grouting pipe (8). Wait for the cement mortar (7) inside the airbag (6) to solidify and complete the construction of the steel pipe pile (1).

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