Fabricated conical barrel bearing platform of transformer substation framework pile foundation in soft soil area and construction method

Abstract

The invention discloses an assembly type cone-barrel bearing platform of a transformer substation framework pile foundation in a soft soil area and a construction method. The assembly type cone-barrel bearing platform comprises a prefabricated cone-barrel bearing platform body, and a circular ring platform is integrally formed on the lower portion of the prefabricated cone-barrel bearing platform body in a pouring mode; an embedded anchor bolt which is connected with a transformer substation component through a bolt is arranged in a cone-shaped body of the prefabricated cone-barrel bearing platform before pouring, and during construction, cement grout is injected into surrounding soil from the interior of a main shaft steel pipe body in a pressure grouting mode while the central main shaft steel pipe body is drilled downwards through a drilling machine. Slurry is squeezed into a soil body around the pile through the holes in the pipe wall, so that the pile body is obviously enlarged, the surface is uneven, combination of the pile body and the surrounding soil body is enhanced, friction resistance of the pile body is increased, and the bearing capacity of the formed pile body is greatly improved. The lower pressure-bearing disc is welded after the top of the main shaft steel pipe is constructed. After the main shaft steel pipe penetrates through a hole of the prefabricated conical barrel bearing platform, an upper bearing disc is welded to the top, and downward force is provided to prevent the prefabricated conical barrel bearing platform from overturning.

Description

Technical Field

[0001] The invention belongs to the technical field of transformer substation framework micro piles, and in particular relates to an assembled cone barrel cap for a transformer substation framework pile foundation in a soft soil area and a construction method thereof. Background Art

[0002] Common foundation forms of transmission line towers include bored cast-in-place pile foundation, cast-in-place concrete foundation (plate type, step type), pile platform foundation, rock anchor pile foundation, prefabricated foundation, etc. Among them, the prefabricated foundation is assembled from multiple reinforced concrete or metal prefabricated parts, and is divided into large excavation foundation and pile foundation. It has fast construction speed, energy saving and emission reduction, and can also be used when there is a lack of sand, gravel, water or it is not suitable to pour concrete on site in winter. However, the commonly used prefabricated foundation has the following disadvantages: 1. The working principle of the prefabricated large excavation foundation is similar to that of the cast-in-place concrete foundation. It mainly relies on the upper covering soil to resist overturning and pulling. Compared with the pile foundation, it occupies a large area and has a low bearing capacity; 2. The cost of the prefabricated metal foundation is relatively high, and the anti-corrosion problem restricts its use; 3. The connection between the prefabricated pile foundation and the upper pedestal mostly uses cast-in-place concrete, which is complicated to construct on site and takes a long time.

[0003] For this purpose, a transmission tower prefabricated assembled cap pile foundation with announcement number "CN207919592U" includes a prefabricated pile and a cap, the cap is located above the prefabricated pile, and is characterized in that: the cap includes a lower cap and an upper cap, the prefabricated pile is provided with four vertically uniformly distributed pre-embedded steel bars centered on the axis of the prefabricated pile, the top of the pre-embedded steel bar is provided with threads, the lower cap and the upper cap are connected to the pre-embedded steel bars through tension steel bars with threads at both ends, the upper end of the tension steel bar is connected with a nut, and the lower end is connected to the pre-embedded steel bar through a straight threaded sleeve. The utility model has a high prefabrication rate, there is no wet work related to the stress of the main structure at the construction site, the workload of on-site construction is reduced, and the tower and line can be erected after installation, and the construction period is short.

[0004] However, for the above-mentioned prefabricated assembled cap pile foundation of the transmission tower, when the cap is larger, multiple lower caps can be stacked in the height direction to facilitate on-site lifting. On the overlapping surface of each cap, pits and bosses are reserved to bite each other to resist the shear force in the horizontal direction, ensuring that multiple caps work together. The diameter of the vertical hole in the cap is not less than three times the diameter of the tension steel bar to ensure that the installation can be completed even if there is a certain construction error. However, there are still the following obvious defects during use: the prefabricated cap is divided into an upper cap and a lower cap, and the two parts of the prefabricated cap are connected by embedded steel bars. The overall weight of the cap is large, and the upper and lower layers make the construction steps more complicated. After installation, it is easy to cause the plane size of the lower cap to be too large, resulting in the problem of excessive total weight. Summary of the invention

[0005] The object of the present invention is to provide an assembled cone barrel cap for a substation frame pile foundation in a soft soil area and a construction method thereof, so as to solve the problems raised in the above-mentioned background technology.

[0006] To achieve the above object, the present invention provides the following technical solution: an assembled cone barrel cap for a micro pile foundation of a substation frame in a soft soil area, comprising:

[0007] A prefabricated cone barrel cap, wherein the lower part of the prefabricated cone barrel cap is integrally cast to form a circular platform with an outer convex circular shape, and the interior of the conical body of the prefabricated cone barrel cap is provided with embedded anchor bolts connected to the substation components by bolts before casting;

[0008] The lower micro pile is welded with a lower pressure plate at the lower end after the casting construction of the lower micro pile. The lower micro pile is a segmented connected grouting steel pipe micro pile, and a main shaft steel pipe is provided at the center of the lower micro pile, and both ends of the main shaft steel pipe are provided with hollow screws for reinforcing the lower micro pile and connecting the segmented connected grouting steel pipe micro piles as a whole with large diameter nuts.

[0009] Preferably, the embedded anchor bolts arranged inside the prefabricated cone barrel foundation are assembled and fixed to the upper substation frame by bolts, so that the substation frame can be constructed and installed in the soft soil area, making it more firm and stable.

[0010] Preferably, holes are evenly distributed around the annular platform at the bottom of the prefabricated cone barrel base for conveniently passing the central spindle steel pipe of the lower micropile, so as to realize the assembly and fixation of the prefabricated cone barrel base and the annular platform.

[0011] Preferably, the holes of the prefabricated cone barrel base are tightly connected to the main shaft steel pipe of the lower micropile and the lower pressure plate, and then an upper pressure plate is welded to the end of the micropile to provide downward force to prevent the prefabricated cone barrel base from overturning.

[0012] Preferably, the lower micro pile and the prefabricated cone barrel cap are connected as a whole to provide a stable support for the substation structure in the soft soil area, so that the bearing capacity of the pile body is greatly improved after the pile is formed.

[0013] Preferably, the main shaft steel pipe at the center of the lower micropile is provided with a spiral blade for drilling the pile body of the main shaft steel pipe into the soft soil area by a drilling rig during construction, and cement slurry can be injected from the main shaft steel pipe body into the surrounding soil by pressure grouting.

[0014] Preferably, the main shaft steel pipe is drilled into the soft soil area by means of spiral blades, and then cement slurry is injected from the periphery of the main shaft steel pipe by means of grouting equipment. The cement slurry is squeezed into the soft body around the lower micro-pile through the holes provided on the wall of the main shaft steel pipe, so that the pile body is significantly enlarged and the surface is uneven, thereby strengthening the connection between the pile body and the surrounding soil.

[0015] Preferably, the main shaft steel pipe includes a drill rod and a spiral blade, and the bottom of the lower micropile is a conical structure, which can further reduce the weight of the base and enhance the strength of the support.

[0016] The present invention also provides a construction method of an assembled cone barrel cap for a micro pile foundation of a substation frame in a soft soil area, which specifically comprises the following steps:

[0017] S1. First, the factory uses a customized conical mold to assemble a prefabricated conical barrel cap with a hollow structure through screws, and then pours UHPC concrete into the mold, stops for a certain period of time, and demoulds it to make a prefabricated conical barrel cap;

[0018] S2. The customized circular platform mold is assembled into a circular platform shape by screws, and UHPC concrete is poured into the mold. After a certain period of time, the mold is demoulded to form a circular platform;

[0019] S3. The prefabricated cone barrel cap prefabricated parts in the step and the prefabricated ring platform in the step are transported by vehicle to the construction site in the soft soil area;

[0020] S4. The lower micro-piles are connected in sections to the grouting steel pipe micro-piles. The center of the pile is the main shaft steel pipe. The main shaft steel pipe is a thin-walled steel pipe or a seamless steel pipe with a small diameter. The main shaft steel pipe is divided into sections according to the construction requirements. Large-diameter nuts are welded at both ends of the main shaft steel pipe of each section. The main shaft steel pipes of each section are tightly connected with hollow screws and large-diameter nuts to form an integral steel pipe pile, and then the integral steel pipe pile is constructed;

[0021] S5. After the top of the main shaft steel pipe is completed in step 1, the lower pressure plate is welded and the prefabricated cone barrel cap is hoisted using hoisting equipment;

[0022] S6. After the main shaft steel pipe passes through the hole of the prefabricated cone barrel cap, the hole and the gap between the main shaft steel pipe are filled with UHPC concrete, and the pressure plate is welded;

[0023] S7. Finally, the upper substation frame is assembled and fixed on the prefabricated cone barrel cap, thereby completing the construction of the assembled cone barrel cap of the micro pile foundation of the substation frame in the soft soil area.

[0024] Compared with the prior art, the technical effects and advantages of the present invention are as follows: the assembled cone barrel cap and construction method of the micro pile foundation of the substation frame in soft soil areas, during construction, a drilling rig is used to drill down the central main shaft steel pipe pile body, and pressure grouting is used to inject cement slurry from the main shaft steel pipe body into the surrounding soil. The slurry is squeezed into the soil around the pile through the holes on the pipe wall, so that the pile body is significantly enlarged and the surface is uneven, which strengthens the combination of the pile body and the surrounding soil, increases the friction resistance of the pile body, and greatly improves the bearing capacity of the pile body after the pile is formed. After the construction of the top of the main shaft steel pipe is completed, the lower pressure plate is welded. After the main shaft steel pipe passes through the hole of the prefabricated cone barrel cap, the upper pressure plate is welded on the top to provide a downward force to prevent the prefabricated cone barrel cap from overturning.

[0025] The burial depth can be changed by adjusting the height of the vertebral body to improve stability. With a certain burial depth and good stability, a cone with a certain slope is used to transmit the upper force to improve the stress of the overall structure. The number of disc holes can accommodate multiple piles. The use of assembly can improve construction efficiency and facilitate construction. The bottom disc has good stability and flexible layout. Environmental pollution may be less. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 It is a structural schematic diagram of the present invention;

[0027] Figure 2 This is a schematic diagram of the main cross-sectional structure of the prefabricated conical barrel cap of the present invention;

[0028] Figure 3 This is a schematic diagram of the structure of the circular ring platform of the present invention;

[0029] Figure 4 It is a schematic diagram of the top view of the circular ring platform of the present invention.

[0030] In the figure: 1. Prefabricated cone barrel base; 2. Circular platform; 3. Embedded anchor bolts; 4. Lower micro piles; 5. Lower pressure plate; 6. Main shaft steel pipe; 8. Hole position; 9. Upper pressure plate; 10. Spiral blades. 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] See also Figure 1-4 The present invention provides a technical solution: an assembled cone barrel cap for a micro pile foundation of a substation frame in a soft soil area, comprising:

[0033] A prefabricated cone barrel cap 1, wherein the lower part of the prefabricated cone barrel cap 1 is integrally cast with a circular platform 2 in an outer convex circular shape, and the circular platform 2 is evenly arranged with 12 holes for the main shaft steel pipe 6 of the lower micro pile 4 to pass through, and the specific number of micro piles can be arranged according to specific requirements, such as 3 micro piles, 4 micro piles, 6 micro piles, 12 micro piles, etc., and the cone body of the prefabricated cone barrel cap 1 is provided with a pre-buried anchor bolt 3 connected to the substation component by bolts before casting, and the pre-buried anchor bolt inside the prefabricated cone barrel cap 1 is connected to the upper substation frame by bolts;

[0034] The lower micro pile 4 is provided with a lower pressure plate 5 and an upper pressure plate 9. The lower end of the lower micro pile 4 after casting construction is welded with the lower pressure plate 5. The lower micro pile 4 is constructed to the design elevation and the lower pressure plate 5 is welded first. The lower micro pile 4 is a segmented connected grouting steel pipe micro pile. The main shaft steel pipe 6 is segmented according to the construction requirements, and the main shaft steel pipe 6 is provided at the center of the lower micro pile 4. The end of the first section of the main shaft steel pipe 6 is provided with a grouting hole, and both ends of the main shaft steel pipe 6 are provided with a hollow screw for reinforcing the lower micro pile 4 and connecting the segmented connected grouting steel pipe micro piles as a whole with a large diameter nut. The segments are tightly connected with a hollow screw and a large diameter nut to form an integral steel pipe pile.

[0035] The embedded anchor bolts 3 arranged inside the prefabricated cone barrel base 1 are assembled and fixed to the upper substation frame by bolts. The circular platform 2 at the bottom of the prefabricated cone barrel base 1 is evenly distributed with holes 8 around it for passing the central main shaft steel pipe 6 of the lower micro pile 4. The specific number of micro piles can be arranged according to specific requirements. After the holes of the prefabricated cone barrel base 1 are tightly connected to the main shaft steel pipe 6 of the lower micro pile 4 and the lower pressure plate 5, an upper pressure plate 9 is welded to the end of the micro pile 4. After the construction of the top of the main shaft steel pipe 6 is completed, the lower pressure plate 5 is welded.

[0036] The lower micro pile 4 and the prefabricated cone barrel base 1 are connected as a whole to provide a stable support for the substation structure in the soft soil area. The main shaft steel pipe 6 at the center of the lower micro pile 4 is provided with a spiral blade 10, which is used to drill the pile body of the main shaft steel pipe 6 into the soft soil area by a drilling rig during construction, so as to facilitate the drilling of the central main shaft steel pipe pile body. After the main shaft steel pipe is drilled into the soft soil area by the spiral blade 10, cement slurry is injected from the periphery of the main shaft steel pipe 6 by grouting equipment, and the cement slurry is squeezed into the soft body around the lower micro pile 4 through the holes provided on the wall of the main shaft steel pipe 6. The main shaft steel pipe 6 includes a drill rod and a spiral blade 10, and the bottom of the lower micro pile 4 is a conical structure.

[0037] The present invention also provides a construction method of an assembled cone barrel cap for a micro pile foundation of a substation frame in a soft soil area, which specifically comprises the following steps:

[0038] S1. First, the factory uses a customized conical mold to assemble a prefabricated conical barrel cap 1 with a hollow structure through screws, and pours UHPC concrete into the mold, and then demolds it for a certain period of time to make a prefabricated conical barrel cap 1;

[0039] S2. The customized circular platform 2 mold is assembled into the shape of a circular platform 2 by screws, and UHPC concrete is poured into the mold, and the mold is demoulded for a certain period of time to form a circular platform 2;

[0040] S3. The prefabricated cone barrel cap 1 prefabricated member in step 1 and the prefabricated ring platform 2 prefabricated member in step 2 are transported by vehicle to the construction site in the soft soil area;

[0041] S4. The lower micro-pile 4 segments are connected to the grouting steel micro-pile, the center of the pile is the main shaft steel pipe 6, the main shaft steel pipe 6 is a thin-walled steel pipe or a seamless steel pipe with a small diameter, the main shaft steel pipe 6 is segmented according to the construction requirements, and the main shaft steel pipe 6 of each segment is welded at both ends with a large diameter nut, and each segment of the main shaft steel pipe 6 is closely connected with a hollow screw and a large diameter nut to form an integral steel pipe pile, and then the overall steel pipe pile construction;

[0042] S5. After the top construction of the main shaft steel pipe 6 in step 4 is completed, the lower pressure plate 5 is welded and the prefabricated cone barrel cap 1 is hoisted using hoisting equipment;

[0043] S6. After the main shaft steel pipe 6 passes through the hole of the prefabricated cone barrel cap 1, the hole and the gap between the main shaft steel pipe 6 are filled with UHPC concrete and welded to the pressure plate 9;

[0044] S7. Finally, the upper substation frame is assembled and fixed on the prefabricated cone barrel cap 1, thereby completing the construction of the assembled cone barrel cap of the micro pile foundation of the substation frame in the soft soil area.

[0045] Specifically, when in use, the prefabricated cone barrel cap 1 has a circular platform 2 at the bottom, the prefabricated cone barrel cap 1 has embedded anchor bolts 3 connected to the upper substation frame by bolts, and the circular platform 2 is evenly arranged with a plurality of holes for the main shaft steel pipe 6 of the lower micro pile 4 to pass through. The lower micro pile 4 has a lower pressure plate 5 and an upper pressure plate 9. When the lower micro pile 4 is constructed to the design elevation, the lower pressure plate 5 is welded first, and then the holes of the prefabricated cone barrel cap 1 are aligned with the main shaft steel pipe 6 of the lower micro pile 4, and the bottom of the prefabricated cone barrel cap 1 is in close contact with the lower pressure plate 5, and then the upper pressure plate 9 is welded. The lower micro pile 4 and the upper prefabricated cone barrel base 1 are connected as a whole to improve stability. Cement slurry is injected from the main shaft steel pipe 6 into the surrounding soil by pressure grouting. The slurry is squeezed into the soft soil around the pile through the holes on the pipe wall, which makes the pile body significantly enlarged and the surface uneven, thereby strengthening the combination of the pile body and the surrounding soil, increasing the friction resistance of the pile body, and greatly improving the bearing capacity of the pile body on the substation structure after the pile is formed.

[0046] Finally, it should be noted that the above is only a preferred embodiment of the present invention and is not intended to limit the present invention. Although the present invention has been described in detail with reference to the aforementioned embodiments, it is still possible for those skilled in the art to modify the technical solutions described in the aforementioned embodiments or to make equivalent substitutions for some of the technical features therein. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. An assembled cone barrel cap for the pile foundation of a transformer substation in a soft soil area, characterized in that: include: A prefabricated conical barrel cap (1), wherein the lower part of the prefabricated conical barrel cap (1) is integrally cast with a circular platform (2) in an outer convex circular shape, and the interior of the conical body of the prefabricated conical barrel cap (1) is provided with pre-buried anchor bolts (3) connected to substation components by bolts before casting; A lower micro pile (4) is provided, after the casting construction, with a lower pressure plate (5) welded to the lower end of the lower micro pile (4), the lower micro pile (4) is a segmented connected grouting steel pipe micro pile, and a main shaft steel pipe (6) is provided at the center of the lower micro pile (4), and hollow screws are provided at both ends of the main shaft steel pipe (6) for reinforcing the lower micro pile (4) and connecting the segmented connected grouting steel pipe micro piles as a whole with large diameter nuts.

2. The assembled cone barrel cap of the substation frame pile foundation in soft soil area according to claim 1 is characterized by: The embedded anchor bolts (3) arranged inside the prefabricated cone-barrel foundation (1) are assembled and fixed to the upper substation frame by bolts.

3. The assembled cone barrel cap of the substation frame pile foundation in soft soil area according to claim 1 is characterized by: Holes (8) are evenly distributed around the annular platform (2) at the bottom of the prefabricated cone barrel support (1) to facilitate the passage of the central main axis steel pipe of the lower micro pile (4).

4. The assembled cone barrel cap for the substation frame pile foundation in soft soil area according to claim 1 is characterized by: The holes of the prefabricated cone barrel support (1) are tightly connected to the main shaft steel pipe (6) and the lower pressure plate (5) of the lower micro pile (4), and then an upper pressure plate (9) is welded to the end of the micro pile (4).

5. The assembled cone barrel cap for the substation frame pile foundation in soft soil area according to claim 1 is characterized by: The lower micro pile (4) and the prefabricated cone barrel cap (1) are connected to form a whole to provide a stable support for the substation structure in the soft soil area.

6. The assembled cone barrel cap for the substation frame pile foundation in soft soil area according to claim 1 is characterized by: The main shaft steel pipe (6) at the center of the lower micro pile (4) is provided with a spiral blade (10) for drilling the pile body of the main shaft steel pipe (6) into the soft soil area by a drilling rig during construction.

7. The assembled cone barrel cap for the substation frame pile foundation in soft soil area according to claim 6, characterized in that: The main shaft steel pipe is drilled into the soft soil area by means of a spiral blade (10), and cement slurry is injected from the periphery of the main shaft steel pipe (6) by means of a grouting device. The cement slurry is squeezed into the soft body around the lower micro pile (4) through holes provided on the wall of the main shaft steel pipe (6).

8. The assembled cone barrel cap for the substation frame pile foundation in soft soil area according to claim 7, characterized in that: The main shaft steel pipe (6) includes a drill rod and a spiral blade (10), and the bottom of the lower micro pile (4) is a conical structure.

9. A construction method for an assembled cone barrel cap for a substation frame pile foundation in a soft soil area according to any one of claims 1 to 8, characterized in that: The specific steps include: S1. First, the factory uses a customized conical mold to combine screws into a prefabricated cone barrel cap (1) with a hollow structure, and pours UHPC concrete into the mold, and then demolds it for a certain period of time to make a prefabricated cone barrel cap (1); S2. The customized circular platform (2) mold is assembled into a circular platform (2) shape by screws, and UHPC concrete is poured into the mold, and the mold is demolded for a certain period of time to form a circular platform (2); S3. The prefabricated cone barrel cap (1) prefabricated part in step 1 and the prefabricated ring platform (2) prefabricated part in step 2 are transported by vehicle to the construction site in the soft soil area; S4. The lower micro pile (4) is connected to the grouting steel pipe micro pile in sections. The center of the pile is the main shaft steel pipe (6). The main shaft steel pipe (6) is a thin-walled steel pipe or a seamless steel pipe with a small diameter. The main shaft steel pipe (6) is segmented according to the construction requirements. The ends of each segment of the main shaft steel pipe (6) are welded with large-diameter nuts. The main shaft steel pipes (6) of each segment are closely connected with the large-diameter nuts by hollow screws to form an integral steel pipe pile, and then the overall steel pipe pile is constructed; S5. After the top construction of the main shaft steel pipe (6) in step 4 is completed, the lower pressure plate (5) is welded and the prefabricated cone barrel cap (1) is hoisted using hoisting equipment; S6. After the main shaft steel pipe (6) passes through the hole of the prefabricated cone barrel cap (1), the hole and the gap between the main shaft steel pipe (6) are filled with UHPC concrete and welded to the pressure plate (9); S7. Finally, the upper substation frame is assembled and fixed on the prefabricated cone barrel cap (1), thereby completing the construction of the assembled cone barrel cap of the micro pile foundation of the substation frame in the soft soil area.

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