Construction method of a concrete-filled steel tube pile strut structure

Abstract

The application relates to a construction method of a steel pipe concrete pile support structure and relates to the field of foundation piles, and comprises the following steps: S1, construction preparation; S2, pile driving, a first pile is driven (or pressed) into the ground, the enlarged head of the first pile is downwardly pressed into the ground by a pile press, and the angle is adjusted; S3, grouting, after the construction of the first pile is completed, grout is injected into a grouting hole of the first pile; S4, pressurization, after the grouting hole is filled with the grout, the upper end of the grouting hole of the first pile is blocked, and the grouting hole is continuously pressurized and grouted, the enlarged head is expanded by the grout, and the grout fills the inner cavity of the sealing plate; or a special rod is used to drive or rotate to press and expand the enlarged head, and the inner cavity of the sealing plate is filled with the grout. The grout is injected into the grouting hole, the enlarged head is expanded by the grout or the special rod, the volume of the lower end of the first pile is increased, the resistance of the first pile in the ground is increased, and the overall bearing capacity is effectively improved.

Description

Technical Field

[0001] This application relates to the field of foundation piles, and in particular to a construction method for a steel-concrete composite pile-supported structure. Background Technology

[0002] Precast piles are piles of various materials and forms (such as wooden piles, concrete square piles, prestressed concrete pipe piles, steel piles, etc.) manufactured in factories or on construction sites, and then inserted into the soil using pile driving equipment. In China's construction industry, the most commonly used precast piles are mainly precast concrete piles and steel piles.

[0003] In related technologies, precast piles include a first pile and a second pile. One end of the first pile is designed as a cone shape to facilitate insertion into the ground, and a steel connecting plate is pre-embedded at the other end. Both ends of the second pile are pre-embedded with steel connecting plates. During construction, the first pile is first inserted into the ground, and then the second pile is coaxially welded and fixed to the end of the first pile through the steel connecting plates. The second pile is then inserted into the ground. Multiple second piles can be added according to construction requirements.

[0004] In practical application, it was found that while the lower end of the first pile was tapered for easier insertion into the ground, this also reduced the overall bearing capacity. Therefore, the inventors provide a construction method for a steel-concrete composite pile-supported structure with high bearing capacity. Summary of the Invention

[0005] In order to improve the bearing capacity of precast piles, this application provides a construction method for steel-concrete composite pile-supported structures.

[0006] The construction method for a steel-concrete composite pile-supported structure provided in this application adopts the following technical solution:

[0007] A construction method for a steel-concrete composite pile-supported structure includes the following steps: S1, construction preparation; S2, pile driving, driving the first pile into the ground, the first pile including a steel pipe column and a concrete column poured inside the steel pipe column, with a grouting hole pre-reserved in the concrete column, the grouting hole coaxially penetrating the concrete column, a duckbill-shaped enlarged head hinged and fixed at one end of the steel pipe column, when the enlarged head rotates inward and assembles, it forms a conical pile tip, which is convenient for penetrating the ground, a sealing plate with good ductility is fitted and fixed on the outside of the enlarged head, and the first pile is driven into the ground with the enlarged head facing downward and the angle adjusted by a pile driver; S3, grouting, after the first pile is constructed, injecting grout into the grouting hole of the first pile; S4, pressurizing, after the grouting hole is filled with grout, sealing the upper end of the grouting hole of the first pile, and continuously pressurizing and grouting into the grouting hole, the grout opens the enlarged head, so that the grout fills the inner cavity of the sealing plate.

[0008] By adopting the above technical solution, an enlarged head is set at the end of the first pile, and a sealing plate with good ductility is set on the outside of the enlarged head to wrap the enlarged head. After the first pile is inserted into the ground, grout is injected into the grouting hole of the first pile, and then the grout in the grouting hole is pressurized and injected to make the grout push open the enlarged head and fill the inside of the sealing plate. After the enlarged head is opened, the volume of the lower end of the first pile increases, which can effectively increase the resistance of the first pile underground, thereby effectively improving the overall bearing capacity. In addition, after the grout solidifies, it can effectively improve the overall structural strength. At the same time, the first pile adopts a structure of steel pipe column and concrete column, which has high overall strength and can further improve the overall bearing capacity.

[0009] Optionally, step S2 also includes driving a second pile into the ground. The second pile includes a steel pipe column and a concrete column poured inside the steel pipe column. A grouting hole is reserved in the concrete column and coaxially penetrates the concrete column. The outer diameter of the second pile is the same as that of the first pile. After the first pile is inserted into the ground, the second pile is coaxially welded and fixed to the upper end of the first pile. The second pile is pressed into the ground by a pile driver. Multiple second piles can be installed according to construction requirements.

[0010] By adopting the above technical solution, connecting the second pile to the upper end of the first pile can extend the overall length, so that the length of the pile support structure inserted into the ground meets the construction requirements.

[0011] Optionally, in step S3, when injecting grout into the grouting hole, the grouting pipe of the grouting equipment is inserted from the upper end of the second pile, the grouting pipe is inserted to the lower end of the first pile, and then the grout is injected into the grouting hole through the grouting pipe; during the grouting process, the grouting pipe is slowly pulled out as the grout rises in the grouting hole.

[0012] By adopting the above technical solution, during grouting, the grouting pipe is inserted into the bottom of the first pile, and then grout is injected into the interior of the first and second piles through the grouting pipe. The grout can fill the grouting hole from bottom to top, which can better expel air and reduce air bubbles in the grout. After the grout solidifies, it can effectively improve the overall structural strength. During the grouting process, the grouting pipe is slowly pulled out as the grout rises, which can reduce the grouting pressure during the grouting process.

[0013] Optionally, before grouting, a pressure plate is fixed at the upper end of the second pile. A clearance hole is opened through the pressure plate for the grouting pipe to pass through. After the grouting hole passes through the clearance hole, a plug is installed at the end of the clearance hole. During the grouting process, as the grout in the grouting hole rises continuously, the plug on the grouting pipe will abut against the pressure plate to seal the clearance hole, and the grouting hole can be directly pressurized.

[0014] By adopting the above technical solution, a pressure plate is fixed at the upper end of the second pile, and a plug is installed on the grouting pipe. As the grouting hole is filled with grout, the grouting pipe is slowly pulled out. When the grouting hole is full, the plug moves with the grouting pipe to the avoidance hole and seals the avoidance hole. Then, step S4 can be directly performed to pressurize, shortening the switching time between S3 and S4 and preventing the grout from solidifying and causing the inability to pressurize. Furthermore, as the pressure in the grouting hole increases, the plug will press tightly against the pressure plate to seal it tightly.

[0015] Optionally, when preparing to pressurize in step S4, first calculate the volume of grout that can be filled into the inner cavity of the sealing plate, and then press the same volume of grout into the grouting hole; or stop pressurizing when the grouting pressure reaches 50MPa.

[0016] By adopting the above technical solution, the volume of the sealing plate cavity is calculated before pressurization, and then an equal volume of grout is injected during the pressurization process. This ensures that the grout can expand the sealing plate and the enlarged head, and prevents the grout from breaking the sealing plate. If the pressure reaches 50MPa before all the grout is injected, grouting should be stopped to prevent excessive pressure from damaging the equipment.

[0017] Optionally, in step S2, the connection between the second pile and the first pile must be fully welded, and there must be no leakage during the pressurization process in step S4.

[0018] By adopting the above technical solution, the joint between the second pile and the first pile is fully welded, which can effectively improve the connection strength between the first pile and the second pile; if leakage occurs at the joint between the first pile and the second pile, it cannot be guaranteed that the grout will open the sealing plate.

[0019] Optionally, during the manufacturing of the first pile's sealing plate, a portion of the sealing plate can be folded and attached to one side of the enlarged head to prevent the sealing plate from breaking during the pressurization process in step S6.

[0020] By adopting the above technical solution and folding part of the sealing plate, the extension of the sealing plate during the process of the slurry spreading the sealing plate can be reduced, thus preventing the sealing plate from breaking.

[0021] Optionally, step S1 includes: leveling the site by leveling the ground at the construction location; determining the pile position by determining the center coordinates of the precast pile according to the geological conditions revealed in the construction drawings and engineering geological report, and marking the center point of the precast pile.

[0022] Optionally, step S3 can also be set to drive or screw in the top rod. After the first pile is constructed, the top rod is inserted into the grouting hole from the top of the first pile using a pile driving device. The enlarged head is opened by the top rod, and then the top rod is pulled out. Step S4 is grouting. Grout is injected into the grouting hole and the sealing plate after the top rod is pulled out.

[0023] By adopting the above technical solution, another method for expanding the enlarged head is provided.

[0024] In summary, this application includes at least one of the following beneficial technical effects:

[0025] 1. By setting an enlarged head at the end of the first pile and a ductile sealing plate on the outside of the enlarged head, the enlarged head is wrapped by the sealing plate. After the first pile is inserted into the ground, grout is injected into the grouting hole of the first pile. Then, the grout in the grouting hole is pressurized and injected, so that the grout pushes open the enlarged head and fills the inside of the sealing plate. After the enlarged head is opened, the volume of the lower end of the first pile increases, which can effectively increase the resistance of the first pile in the ground, thereby effectively improving the overall bearing capacity. In addition, after the grout solidifies, it can effectively improve the overall structural strength. At the same time, the first pile adopts a structure of steel pipe column and concrete column, which has high overall strength and can further improve the overall bearing capacity.

[0026] 2. By inserting the grouting pipe into the bottom of the first pile during grouting, and then injecting grout into the interior of the first and second piles through the grouting pipe, the grout can fill the grouting hole from bottom to top, which can better expel air and reduce air bubbles in the grout. After the grout solidifies, it can effectively improve the overall structural strength. During the grouting process, the grouting pipe is slowly pulled out as the grout rises, which can reduce the grouting pressure during the grouting process.

[0027] 3. By fixing a pressure plate at the upper end of the second pile and installing a plug on the grouting pipe, the grouting pipe is slowly pulled out as the grouting hole is filled with grout. When the grouting hole is full, the plug moves with the grouting pipe to the avoidance hole and seals the avoidance hole. Then, step S4 can be directly performed to pressurize, shortening the switching time between S3 and S4, preventing the grout from solidifying and causing the inability to pressurize. As the pressure in the grouting hole increases, the plug will press tightly against the pressure plate to seal it tightly. Attached Figure Description

[0028] Figure 1 This is a construction flowchart of this application;

[0029] Figure 2 This is a schematic diagram of the overall structure of Embodiment 1 of this application;

[0030] Figure 3 This is a schematic diagram of the structure of Embodiment 1 of this application, highlighting the enlarged head after it has been opened;

[0031] Figure 4 This is a schematic diagram of the structure of Embodiment 2 of this application, highlighting the expanded head.

[0032] Attached reference numerals: 1. First pile; 11. Steel pipe column; 111. Outer pipe; 112. Inner pipe; 113. Connecting plate; 12. Concrete column; 13. Grouting hole; 14. Enlarged head; 15. Sealing plate; 2. Second pile; 31. Pressure plate; 311. Clearance hole; 32. Grouting pipe; 33. Plug; 4. Top rod. Detailed Implementation

[0033] Example 1:

[0034] This application discloses a construction method for a steel-concrete composite pile-supported structure, referring to... Figure 1 This includes the following steps:

[0035] S1: Construction preparation, including site leveling and pile location determination. The construction site needs to be leveled first; then, based on the geological conditions revealed by the construction drawings and engineering geological report, the center coordinates of the precast piles are determined and the center point of the precast piles is marked.

[0036] S2: Piling, drive the first pile 1 into the ground, refer to... Figure 2 and Figure 3 The first assembly includes a steel pipe column 11 and a concrete column 12 cast inside the steel pipe column 11. The steel pipe column 11 includes an outer pipe 111 and an inner pipe 112. The inner pipe 112 is coaxially inserted inside the outer pipe 111. A connecting plate 113 is welded and fixed between the outer pipe 111 and the inner pipe 112. Multiple connecting plates 113 are evenly distributed along the circumference of the inner pipe 112. The concrete column 12 is cast between the inner pipe 112 and the outer pipe 111. The inner cavity of the inner pipe 112 is configured as a grouting hole 13. A duckbill-shaped enlarged head 14 is hinged and fixed at one end of the outer tube 111. When the enlarged head 14 rotates inward and assembles, it forms a conical pile tip, which is convenient for penetrating into the ground. A sealing plate 15 with good ductility is sleeved and fixed on the outside of the enlarged head 14. When the enlarged head 14 is opened around the hinge point, the enlarged head 14 expands the sealing plate 15, so that the sealing plate 15 wraps around the outside of the enlarged head 14. In order to ensure that the sealing plate 15 will not be damaged when it is expanded, the sealing plate 15 is folded between the two enlarged heads 14. When the enlarged head 14 is opened, the folded part of the sealing plate 15 can be directly expanded.

[0037] When driving the first pile 1, the first pile 1 is first lifted by a crane with the enlarged head 14 of the first pile 1 facing downward. Then the first pile 1 is installed on the pile driver, and the angle of the first pile 1 is adjusted by the pile driver before being driven into the ground.

[0038] After the first pile 1 is constructed, the second pile 2 is driven in. The structure of the second pile 2 is the same as that of the first pile 1, except that the end of the second pile 2 does not have an enlarged head 14. The second pile 2 is lifted by a crane and then installed on a pile driver. The pile driver aligns the ends of the second pile 2 with those of the first pile 1, making them coaxial. Then, the joint of the outer tube 111 of the second pile 2 and the first pile 1 is welded, requiring a full weld. After welding, the second pile 2 is driven into the ground by the pile driver, and multiple second piles 2 are installed according to construction requirements.

[0039] S3: Grouting. After the second pile 2 is constructed, grout is injected into the grouting holes 13 of the first pile 1 and the second pile 2 through a grouting device from the upper end of the second pile 2. The grouting device includes a pressure plate 31, a grouting pipe 32, and a plug 33. A clearance hole 311 is provided through the pressure plate 31. The outlet end of the grouting pipe 32 passes through the clearance hole 311. Then, the plug 33 is fixed to the outlet end of the grouting pipe 32. Finally, the pressure plate 31 is fixed to the top of the second pile 2 with bolts, and the grouting pipe 32 is inserted into the bottom of the first pile 1. The grouting device injects grout into the grouting holes 13 of the first pile 1 and the second pile 2 through the grouting pipe 32. During the grouting process, the grout level gradually rises in the grouting hole 13. When the grout level rises, the grouting pipe 32 is slowly pulled out at the same speed, so that the outlet of the grouting pipe 32 is always kept close to the upper end of the grout, thereby reducing the grouting pressure. After the grouting hole 13 is filled with grout, the plug 33 on the grouting pipe 32 moves to the clearance hole 311 and seals the clearance hole 311.

[0040] S4: Pressurization. After the plug 33 seals the clearance hole 311, pressurize and inject grout into the grouting hole 13 using grouting equipment. Before pressurization, calculate the volume of the inner cavity of the sealing plate 15, and then inject the same volume of grout into the grouting hole 13 during pressurization to ensure that the grout can expand the sealing plate 15 and the enlarged head 14, while preventing the sealing plate 15 from over-stretching and cracking. If the grouting pressure exceeds 50MPa during pressurization, stop grouting immediately to prevent damage to the grouting equipment due to excessive pressure.

[0041] After the grout has solidified, the pressure plate 31 and grouting pipe 32 can be removed to grout the next pile.

[0042] The implementation principle of the construction method for a steel-concrete composite pile-supported structure disclosed in Embodiment 1 of this application is as follows: An enlarged head 14 is hinged to the end of the first pile 1, and a ductile sealing plate 15 is installed on the outside of the enlarged head 14 to enclose it. After the first pile 1 is inserted into the ground, grout is injected into the grouting hole 13 of the first pile 1. Then, the grout in the grouting hole 13 is pressurized and injected, causing the grout to push open the enlarged head 14 and fill the interior of the sealing plate 15. After the enlarged head 14 is opened, the volume of the lower end of the first pile 1 increases, which can effectively increase the resistance of the first pile 1 underground, thereby effectively improving the overall bearing capacity. Furthermore, after the grout solidifies, it can effectively improve the overall structural strength.

[0043] Example 2:

[0044] The difference between Embodiment 2 and Embodiment 1 of this application is that, referring to... Figure 1 and Figure 4 Step S3 is set to drive or screw in the top rod 4. After the construction of the first pile 1 and the second pile 2 is completed, the top rod 4 is driven into or screwed into the grouting hole 13 by the pile driving equipment. The enlarged head 14 is opened by the top rod 4, and then the top rod 4 is slowly pulled out.

[0045] Step S4 is set to grouting. After the top rod 4 is pulled out, grout is injected into the grouting hole 13 and the sealing plate 15. The grouting pipe of the grouting equipment is inserted from the grouting hole 13 to the bottom of the first pile 1. Grout is injected into the sealing plate 15 and the grouting hole 13 through the grouting pipe. As the grout level rises, the grouting pipe is slowly pulled out until the grout fills the grouting hole 13.

[0046] The above are all preferred embodiments of this application, and are not intended to limit the scope of protection of this application. Therefore, all equivalent changes made in accordance with the structure, shape and principle of this application should be covered within the scope of protection of this application.

Claims

1. A construction method for a steel-concrete composite pile-supported structure, characterized in that: Includes the following steps: S1, Construction preparation; S2, piling, driving the first pile (1) into the ground. The first pile (1) includes a steel pipe column (11) and a concrete column (12) poured inside the steel pipe column (11). A grouting hole (13) is reserved in the concrete column (12). The grouting hole (13) coaxially penetrates the concrete column (12). A duckbill-shaped enlarged head (14) is hinged and fixed at one end of the steel pipe column (11). When the enlarged head (14) rotates inward and assembles, it forms a cone-shaped pile tip, which is convenient to penetrate into the ground. A sealing plate (15) with good ductility is fitted and fixed on the outside of the enlarged head (14). The enlarged head (14) of the first pile (1) is driven into the ground with the angle adjusted downward by the pile driver. S3, grouting, after the first pile (1) is constructed, grout is injected into the grouting hole (13) of the first pile (1); S4, pressurize, after filling the grouting hole (13) with grout, seal the upper end of the grouting hole (13) of the first pile (1), and continuously pressurize and grout into the grouting hole (13) to expand the enlarged head (14) through the grout, so that the grout fills the inner cavity of the sealing plate (15); Step S2 also includes driving a second pile (2) into the ground. The second pile (2) includes a steel pipe column (11) and a concrete column (12) poured inside the steel pipe column (11). A grouting hole (13) is reserved in the concrete column (12). The grouting hole (13) coaxially penetrates the concrete column (12). The second pile (2) has the same outer diameter as the first pile (1). After the first pile (1) is inserted into the ground, the second pile (2) is coaxially welded and fixed to the upper end of the first pile (1). The second pile (2) is pressed into the ground by a pile driver. Multiple second piles (2) are installed according to construction requirements. In step S3, when injecting grout into the grouting hole (13), the grouting pipe (32) of the grouting equipment is inserted from the upper end of the second pile (2), and the grouting pipe (32) is inserted into the lower end of the first pile (1). Then, grout is injected into the grouting hole (13) through the grouting pipe (32). During the grouting process, the grouting pipe (32) is slowly pulled out as the grout rises in the grouting hole (13). Before grouting, a pressure plate (31) is fixed at the upper end of the second pile (2). A clearance hole (311) is opened through the pressure plate (31) for the grouting pipe (32) to pass through. After the grouting pipe (32) passes through the clearance hole (311), a plug (33) is fixed at the outlet end of the grouting pipe (32). During the grouting process, as the grout in the grouting hole (13) rises continuously, the plug (33) on the grouting pipe (32) will abut against the pressure plate (31) to seal the clearance hole (311), and the grouting hole (13) can be directly pressurized.

2. The construction method for a steel-concrete composite pile-supported structure according to claim 1, characterized in that: When preparing to pressurize in step S4, first calculate the volume of grout that can be filled in the inner cavity of the sealing plate (15), and then press the same volume of grout into the grouting hole (13); or stop pressurizing when the grouting pressure reaches 50MPa.

3. The construction method for a steel-concrete composite pile-supported structure according to claim 1, characterized in that: In step S2, the connection between the second pile (2) and the first pile (1) must be fully welded, and there must be no leakage during the pressurization process in step S4.

4. The construction method for a steel-concrete composite pile-supported structure according to claim 1, characterized in that: During the manufacturing of the first pile (1), part of the sealing plate (15) is folded and attached to one side of the enlarged head (14) to prevent the sealing plate (15) from breaking during the pressurization process in step S6.

5. The construction method for a steel-concrete composite pile-supported structure according to claim 1, characterized in that: Step S1 includes: leveling the site, leveling the ground at the construction location; Determine the pile location. Based on the geological conditions revealed in the construction drawings and engineering geological report, determine the center coordinates of the precast pile and mark the center point of the precast pile.

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