Expanded-base rotor steel pipe pile and construction technology thereof

Abstract

The invention relates to the technical field of building construction, in particular to a bottom-expanded rotor steel pipe pile and a construction technology thereof.The bottom-expanded rotor steel pipe pile comprises a pile body steel pipe, a bottom-expanded wing ring and a pile top grouting blind plate, one end of the pile top grouting blind plate is a connector end, and the connector end is connected with the power end of a drilling machine; the rotary cutting is performed through the bottom-expanded wing ring; an injection cavity is formed in the pile body steel pipe. According to the bottom-expanded rotor steel pipe pile, the large bearing capacity can be provided under the small diameter. The steel pipe pile can form a larger bearing area in soil, so that the bearing capacity of a single pile is remarkably improved, and the steel pipe pile is suitable for various types of soil and rocks including soft soil, sandy soil, cohesive soil, soft rocks and the like. The rotary cutting mode is adopted for burying, the construction process is relatively simple and rapid, and the construction efficiency can be remarkably improved. And meanwhile, a large amount of slurry treatment and dumping operation are not needed, so that the construction time and cost are further saved.

Description

Technical Field

[0001] This invention relates to the field of civil engineering pile foundation technology, specifically to an enlarged-base rotor steel pipe pile and its construction process, which aims to improve the bearing capacity and construction efficiency of pile foundations, and is particularly suitable for foundation engineering construction under complex geological and confined space conditions. Background Technology

[0002] In building construction, pile foundations are a commonly used type of foundation, whose main function is to transfer the load of the building to deep, stable soil or rock layers. Traditional pile types, such as cast-in-place piles and precast piles, have some problems during construction, such as long construction cycles and difficulty in quality control for cast-in-place piles; and precast piles are easily damaged when penetrating hard soil layers.

[0003] To address these issues, several new types of piles have emerged in recent years, such as enlarged-base piles and helical piles. Enlarged-base piles increase the pile's bearing capacity by forming an enlarged head at the pile bottom; helical piles, on the other hand, utilize the rotation of helical blades to drive the pile body into the soil, resulting in faster construction speeds and less environmental impact.

[0004] However, existing enlarged-base piles and helical piles also have some shortcomings. The enlarged head of enlarged-base piles is usually formed by mechanical or blasting methods, which is difficult and costly to construct; helical piles have relatively low bearing capacity and are prone to instability in soft soil areas.

[0005] Therefore, a new type of pile and its construction technology are needed that can improve the bearing capacity of the pile, reduce the construction difficulty and cost, and adapt to different geological conditions. Summary of the Invention

[0006] The technical problem to be solved by the present invention is to overcome the shortcomings of the prior art and provide an expanded-base rotor steel pipe pile and its construction process.

[0007] The technical solution adopted in this invention is: The expanded-base rotor steel pipe pile includes: a pile body steel pipe, an expanded-base rotor ring, and a pile top grouting blind plate. One end of the pile top grouting blind plate is a joint end, which is connected to the power end of the drilling rig; it is driven into the soil by the rotating expanded-base rotor ring; an injection cavity is provided inside the pile body steel pipe.

[0008] Furthermore, the pile body steel pipe includes a first pile steel pipe, multiple standard pile steel pipes without flanks and standard pile steel pipes with flanks, and adjacent standard pile steel pipes are bolted together using connecting rings;

[0009] Furthermore, the expanded bottom wing ring includes two or more involute-shaped expanded wings, which are staggered and fixed on the first pile steel pipe and the standard pile steel pipe with expanded wings; the axis of the involute expanded wings is staggered with the axis of the pile steel pipe.

[0010] Furthermore, one end of the first section of the steel pipe is the pile tip breaking through the ground, and the other end is welded with a connecting ring bolt to connect to the standard section of the pile. Two or more involute-shaped expanding wings breaking through the ground are respectively set on the pile body of the first section of the steel pipe, and an alloy steel column is welded to the pile tip area of ​​the first section of the steel pipe, and a grouting hole is opened at the pile tip.

[0011] Furthermore, the two ends of the standard section pile steel pipe without flared wings are welded with connecting rings;

[0012] Furthermore, the steel pipe with expanded wing section has connecting rings welded to both ends, and expanded wing rings evenly welded around its circumference;

[0013] Furthermore, a grouting blind plate is bolted to the pile top steel pipe, and the grouting blind plate communicates with the injection cavity inside the pile body steel pipe;

[0014] A construction technique, applied to any of the aforementioned enlarged-base rotor steel pipe piles, includes the following steps: Step 1: Steel pipe pile fabrication: Fabricate the pile body steel pipe, enlarged bottom wing ring, and connecting ring off-site according to the preset dimensions, and weld the pile body steel pipe to the enlarged bottom wing ring and connecting ring; Step 2: Site leveling: Clean the construction site, level the ground, and ensure the normal operation of construction machinery; Step 3: Pile location layout: Based on the design drawings, use surveying instruments such as a total station to lay out the pile locations and determine the position of the piles; Step 4: Drilling Rig Positioning: Move the drilling rig to the pile location, adjust the position and verticality of the drilling rig, and ensure that the drill bit of the drilling rig coincides with the center of the pile steel pipe; Step 5: Pre-hole drilling: Start the drilling rig and perform pre-hole drilling using methods such as rotary drilling or percussion drilling. During the drilling process, adjust the drilling parameters according to the geological conditions to ensure the quality of the pre-hole drilling; Step Six: Steel Pipe Pile Construction: Connect the end of the first section of the steel pipe to the power end of the drilling rig via a connecting ring, allowing the pile tip and the enlarged bottom wing ring to rotate and drill into the pilot hole. After penetrating to the preset depth, disconnect the first section of the steel pipe from the drilling rig. Step 7: Connect the piles sequentially: Connect the standard steel pipe sections without flared wings or with flared wings in one go according to Step 6 until the tip of the pile body reaches the design depth. Step 8: High-pressure grouting: Cement grout or other chemical grouts are injected into the pile bottom and surrounding soil through the injection cavity of the pile body steel pipe connected to the pile top grouting blind plate to improve the strength and stability of the pile bottom and surrounding soil.

[0015] As can be seen from the above construction process, compared with traditional steel pipe piles, the present invention has the following beneficial effects: The expanded-base rotor steel pipe pile of this invention can provide a large bearing capacity with a small diameter. This allows the steel pipe pile to form a larger bearing area in the soil, thus significantly improving the bearing capacity of a single pile. It is suitable for various types of soil and rock, including soft soil, sandy soil, cohesive soil, and soft rock. This invention uses a rotary cutting method to drive the pile into the soil, making the construction process relatively simple and quick, significantly improving construction efficiency. Simultaneously, since it eliminates the need for extensive mud treatment and soil removal, it further saves construction time and costs and reduces mud pollution to the environment. This invention eliminates the need for on-site welding, reducing the risk of hot work and ensuring high safety. Furthermore, due to its high construction efficiency and low material usage, it also reduces energy consumption and carbon emissions, aligning with current green building and sustainable development concepts. This invention has high bearing capacity and construction efficiency, reducing the number of piles required and saving material costs. It also has the advantages of a short rest period and high economic benefits. When the steel pipe pile needs to resist horizontal loads, concrete, cement grout, or crushed stone + cement grout can be poured into the steel pipe core to increase the steel pipe pile's resistance to horizontal loads. If this invention is successfully applied and promoted, it will surely bring huge social and economic benefits. Attached Figure Description

[0016] The present invention will be further described below with reference to the accompanying drawings and embodiments:

[0017] Figure 1 This is a schematic diagram of the structure of the expanded-base rotor steel pipe pile provided in an embodiment of the present invention; Figure 2 A schematic diagram of the first section of the steel pipe of the expanded-base rotor steel pipe pile provided in an embodiment of the present invention; Figure 3 A schematic diagram of a standard section pile without wing expansion of a winged steel pipe pile provided in an embodiment of the present invention; Figure 4 A schematic diagram of a standard section pile with expanded wings for a rotary steel pipe pile provided in an embodiment of the present invention; Figure 5 A schematic diagram of the connecting ring of the expanded-base rotor steel pipe pile provided in this embodiment of the invention; Figure 6 This is a schematic diagram of the first direction of the wing ring of the expanded-base rotor steel pipe pile provided in an embodiment of the present invention; Figure 7 This is a schematic diagram of the second direction of the wing ring of the expanded-base rotor steel pipe pile provided in an embodiment of the present invention; Figure 8 This is a schematic diagram of the first direction of the grouting blind plate at the top of the expanded-base rotor steel pipe pile provided in an embodiment of the present invention; Figure 9 This is a schematic diagram of the second direction of the grouting blind plate at the top of the expanded-base rotor steel pipe pile provided in an embodiment of the present invention. Detailed Implementation

[0018]

Example 1

[0019] The working principle and technical effects of the above technical solution are as follows: This invention provides an expanded-base rotor steel pipe pile, which can provide a large bearing capacity with a small diameter. This allows the steel pipe pile to form a larger bearing area in the soil, thereby significantly improving the bearing capacity of a single pile. It is suitable for various types of soil and rock, including soft soil, sandy soil, cohesive soil, soft rock, etc. During construction, firstly, the pile body steel pipe (7), the expanded-base rotor ring (5), and the alloy steel column (102) are made according to the preset dimensions, and the pile body steel pipe (7), the expanded-base rotor ring (5), and the alloy steel column (102) are connected together; then, the joint end of the pile body steel pipe is connected to the power end of the drilling equipment through the connecting ring (4) bolt, and the power of the drilling equipment is transmitted to the steel pipe pile through the flange bolt connection. The alloy steel column (102) at the pile tip breaks through the soil layer, and the pile body steel pipe (7) and the expanded-base rotor ring (5) rotate and cut into the soil. After entering the soil to the preset depth, Disconnect the first section of the pile steel pipe connecting ring (4) from the power end of the drilling equipment; connect the standard section pile (2) without expansion wing and the standard section pile (3) with expansion wing in sequence according to the above steps, and finally inject grout into the pile body steel pipe (7) to increase the horizontal and vertical load resistance of the steel pipe pile; the present invention uses a rotary cutting method to enter the soil, the construction process is relatively simple and quick, and can significantly improve the construction efficiency; at the same time, since there is no need to carry out a large amount of mud treatment and soil removal, it further saves construction time and cost and reduces the pollution of mud to the environment. The present invention does not require on-site welding, reduces the risk source of hot work, and has high safety; in addition, due to the high construction efficiency and low material usage, it also reduces energy consumption and carbon emissions, which is in line with the current concept of green building and sustainable development; the present invention has high bearing capacity and construction efficiency, which can reduce the number of piles and save material costs; at the same time, it has the advantages of short rest period and high economic benefits; when the steel pipe pile needs to resist horizontal load, concrete, cement grout, or crushed stone + cement grout can be injected into the steel pipe core to increase the horizontal load resistance of the steel pipe pile.

[0020] The pile body steel pipe (7) includes a first pile steel pipe (1) and two or more standard pile sections without wing expansion (2) and standard pile sections with wing expansion (3). Adjacent steel pipe sections are connected by a detachable connection, and multiple standard steel pipe sections can be bolted together by connecting rings (4). When the construction height is limited and the operating space is restricted, the present invention can manufacture the pile core steel pipe in sections and construct in segments. Multiple standard steel pipe sections are bolted together by connecting rings (4). The construction speed is fast, the rest period is short, and the pile can be put into use without the need for concrete curing after construction.

[0021] The expanded bottom wing ring (5) includes an involute wing, which is fixed relative to the drilling end of the first pile steel pipe (1) and the standard pile (3) with the expanded wing. The axis of the involute wing is staggered with the axis of the pile steel pipe. The expanded bottom wing ring (5) is welded to the pile steel pipe at an appropriate angle according to different soil layers, which is beneficial to improving its drilling and soil breaking effect in different soil environments.

[0022] The steel pipe pile is provided with a pile top grouting blind plate (6), and the grouting port of the pile top grouting blind plate (6) is connected to the cavity inside the steel pipe pile.

[0023] Here is an example of an engineering application: The project is located in a petrochemical industrial park in a city in southern my country. Due to the increased load from pipeline additions, a pier cap with pile foundations is planned to be installed in the middle of the pipe gallery. The reinforcement pile foundation construction is located below the existing pipe gallery, with a construction clearance of approximately 3.5 to 4.3 meters. Pile foundation construction is being carried out in a space of only 3.5 to 4.3 meters, constituting ultra-low clearance construction, making the construction extremely difficult. Furthermore, the pipe gallery will remain operational during construction, requiring strict control over the construction height and horizontal range, ensuring that vibrations do not affect operation. The pipes contain toxic and hazardous substances, making the safety requirements extremely high and the project inherently very dangerous.

[0024] The soil layers within the site are distributed as follows: ① Plain fill; ②1 Medium sand; ②2 Gravel; ②3 Silty clay containing gravel; ③ Silty clay; ④ Completely weathered mudstone.

[0025] This project uses conventional pile foundation design with a pile diameter of 500 mm, a wall thickness of 8 mm, and a pile length of 17 meters. The bearing capacity requirement is met by using layer ④, completely weathered mudstone, as the bearing stratum. Constructing a 17-meter-long, 500 mm-diameter pile foundation within a clearance of approximately 3.5-4.3 meters presents significant construction challenges, high costs, and a lengthy construction period. In contrast, using expanded-base rotor steel pipe piles requires only one expanded-base rotor steel pipe pile per pile cap, with a total pile length of 8-16 meters, a standard section pile length of 1.5-2 meters, a pile diameter of 325 mm, and an expanded flange of 650 mm. This can be constructed in sections, using layer ③ (pebble layer) or layer ④ (silty clay layer) as the bearing stratum to meet the bearing capacity requirements. Compared to conventional methods, this approach can save over 50% of the construction time and 20% to 50% of the cost.

[0026] Successful implementation process of the construction method: During the implementation of this project, due to the constraints on the construction clearance and the fact that the construction area is located within the production unit area and welding is not advisable, the specifications of the expanded-base rotor steel pipe piles are as follows: pile diameter 325 mm, steel pipe wall thickness 8 mm, expanded-base wing ring 650 mm, first section pile steel pipe length 2 meters, standard section pile steel pipe length 1.5 meters, and standard sections are connected to each other and to the first section using bolted connectors.

[0027] The specific construction steps for this project are as follows: According to the design requirements, select appropriate pile body steel pipe (7) and expanded bottom wing ring (5) sizes to manufacture multiple standard section piles (2) without expanded wing and standard section piles (3) with expanded wing. Connecting rings (4) are provided at the connection of multiple steel pipe standard section piles. Adjacent steel pipe standard sections are firmly connected by connecting rings (4) to form a pile body steel pipe (7) with a preset length. Expanded bottom wing ring (5) is installed at the end of the pile body steel pipe (7) at a preset angle. Then, using appropriate drilling equipment, the first pile steel pipe (1) is connected to the drilling rig power head to transmit the drilling rig power to the steel pipe pile, so that the alloy steel column (102) breaks through the soil layer below and the expanded bottom wing ring (5) rotates and cuts into the soil.

[0028] After the first section of the steel pipe (1) is driven into the soil to a certain depth, the pile is spliced. The standard section of the steel pipe is bolted together by connecting rings. The above steps are repeated until the design elevation is reached.

[0029] When steel pipe piles need to resist horizontal and vertical loads, cement grout can be injected into the steel pipe (7) of the pile body to increase the bearing capacity of the steel pipe pile; grouting ports can be reserved on the pile side and pile end, and grouting on the pile side and pile end increases the resistance of the pile side and pile end, further improving the horizontal and vertical bearing capacity of the pile foundation.

[0030]

Example 2

[0031] The expanded-base rotor steel pipe piles installed using the above construction process employ a rotary cutting method for soil insertion, resulting in a relatively simple and quick construction process that significantly improves construction efficiency. Furthermore, the elimination of extensive mud treatment and soil removal operations further saves construction time and costs, and reduces mud pollution to the environment. The absence of on-site welding reduces the risk of open flame operations, ensuring high safety. Grouting can also be performed on the pile sides and ends to increase pile resistance and improve bearing capacity, resulting in a low overall cost.

[0032] In this invention, unless otherwise explicitly specified and limited, the terms "installation," "connection," "linking," and "fixing," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection, an electrical connection, or a connection that allows communication between them; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components, unless otherwise explicitly limited. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

Claims

1. A type of expanded-base rotor steel pipe pile, characterized in that, include: The pile body steel pipe (7), the expanded bottom wing ring (5), and the pile top grouting blind plate (6) are all included. One end of the pile top grouting blind plate (6) is a joint end, which is connected to the power end of the drilling rig; it is inserted into the soil by rotating and cutting through the expanded bottom wing ring (5); the pile body steel pipe (7) is provided with an injection cavity.

2. The expanded-base rotor steel pipe pile according to claim 1, characterized in that, The pile body steel pipe includes the first pile steel pipe (1), multiple standard pile steel pipes without expansion wings (2) and standard pile steel pipes with expansion wings (3), and adjacent standard steel pipe sections are bolted together by connecting rings (4).

3. The expanded-base rotor steel pipe pile according to claim 1, characterized in that... The expanded bottom wing ring (5) includes two or more involute winglets, which are staggered and fixed on the first pile steel pipe (1) and the standard pile steel pipe (3) with winglets; the axis of the involute winglets is staggered with the axis of the pile body steel pipe (7).

4. The expanded-base rotor steel pipe pile according to claim 2, characterized in that, One end of the first section of the steel pipe (1) is the soil-breaking end of the pile tip, and the other end is welded with a connecting ring (4) to connect to the standard section of the pile. Two or more involute-shaped winged soil-breaking ends are respectively set on the pile body of the first section of the steel pipe. The pile tip area of ​​the first section of the steel pipe (1) is welded with a steel bar head (102) and a grouting hole (101) is opened at the pile tip.

5. The expanded-base rotor steel pipe pile according to claim 2, characterized in that, The two ends of the standard section pile steel pipe (2) without wing expansion are welded with connecting rings.

6. The expanded-base rotor steel pipe pile according to claim 2, characterized in that, The steel pipe (3) with wing expansion is welded with connecting rings at both ends and with wing expansion rings (5) evenly welded around its body.

7. The expanded-base rotor steel pipe pile according to claim 1, characterized in that, The pile body steel pipe (7) is bolted with a pile top grouting blind plate (6), which is connected to the injection cavity inside the pile body steel pipe (7).

8. A construction process applied to the expanded-base rotor steel pipe piles according to any one of claims 1-7, characterized in that, The process includes the following steps: Step 1: Fabricate the pile body steel pipe (7), the expanded bottom wing ring (5), and the connecting ring (4) off-site according to the preset dimensions, and weld the pile body steel pipe to the expanded bottom wing ring and the connecting ring; Step 2: Site leveling: Clean the construction site, level the ground, and ensure the normal operation of construction machinery; Step 3: Pile location layout: Based on the design drawings, use surveying instruments such as a total station to lay out the pile locations and determine the position of the piles; Step 4: Drilling rig positioning: Move the drilling rig to the pile location, adjust the position and verticality of the drilling rig, and ensure that the drill bit of the drilling rig coincides with the center of the pile steel pipe (7); Step 5: Pre-hole drilling: Start the drilling rig and perform pre-hole drilling using methods such as rotary drilling or percussion drilling. During the drilling process, adjust the drilling parameters according to the geological conditions to ensure the quality of the pre-hole drilling; Step Six: Steel Pipe Pile Construction: Connect the end of the first section of the steel pipe (1) to the power end of the drilling equipment via a connecting ring (4), so that the pile tip and the under-expansion wing ring (5) can be rotated and drilled into the pilot hole. After the pile reaches the preset depth, disconnect the connection between the first section of the steel pipe and the drilling equipment; Step 7: Connect the piles in sequence: Connect the standard steel pipe section (2) without wing expansion or the standard steel pipe section with wing expansion in one step according to Step 6 until the pile tip of the pile body steel pipe (7) reaches the design depth; Step 8: High-pressure grouting: Cement grout or other chemical grouts are injected into the pile bottom enlarged head and the surrounding soil through the grouting pipe to improve the strength and stability of the pile bottom and the surrounding soil.

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