A micro-disturbance composite structure anchor rod static pressure steel pipe pile in a limited space and a construction method thereof

Abstract

This invention discloses a micro-disturbance composite structure anchored static pressure steel pipe pile and its construction method within a confined space. The pile comprises a steel pipe pile, a central rotating member, a shear key, shear key connecting members, a pile tip, and a cement-soil reinforced body. The steel pipe pile has deployable shear keys connected to the central rotating member via shear key connecting members. The cement-soil reinforced body is formed using a micro-disturbance process and then inserted into the pile body using an anchored static pressure process. A rotating mechanical device is then installed at the top of the pile and connected to the central rotating member. Controlling the rotation of the central rotating member causes the shear keys to unfold and enter the cement-soil reinforced body, forming a composite structure anchored static pressure pile. This invention solves the problems of large environmental disturbance and low single-pile bearing capacity during anchored static pressure pile construction by combining the cement-soil reinforced body formed by the micro-disturbance process with the composite pile formed by the anchored static pressure process.

Description

Technical Field

[0001] This invention relates to the field of building engineering and underground engineering construction technology, and in particular to a foundation reinforcement technology applicable to urban renewal, adjacent existing buildings and structures and other limited space conditions. Specifically, it relates to a micro-disturbance composite structure anchor static pressure steel pipe pile and construction method in a limited space. Background Technology

[0002] With the development of urban construction, urban renewal projects are increasing, making foundation reinforcement within existing buildings much more difficult due to site conditions and height limitations. While traditional anchor static pressure piles for foundation reinforcement have advantages such as compact construction equipment and applicability in confined spaces, they also face two significant technical bottlenecks: 1. Significant construction disturbance: During the driving of precast piles, the pile body exerts a strong squeezing effect on the surrounding soil, which can easily lead to soil displacement and have an adverse impact on the adjacent foundation pit support structure, pipelines and building foundations, also known as the "soil squeezing effect".

[0003] 2. Limited bearing capacity of a single pile: Traditional anchored static pressure piles mainly rely on the side friction of the pile body and the end resistance of the pile to provide bearing capacity. In a limited space, the pile diameter and pile length are often restricted, and the sidewalls of the steel pipe pile itself are smooth with low frictional resistance, making it difficult for its single pile bearing capacity to meet engineering requirements.

[0004] In existing technologies, such as patent (CN118880858A), a composite friction steel pile device is proposed, which increases the friction between the pile and the stratum through telescopic wings. However, this technology has obvious defects: after the telescopic wings are deployed, they only insert into the natural soil layer, resulting in limited bonding strength with the soil and poor load-bearing capacity improvement; during construction, the insertion of the pile still generates a soil squeezing effect, failing to solve the disturbance problem; its locking components and transmission structure are complex, making operation difficult in confined spaces with low clearance, and pile extraction relies on a specific hook structure, limiting its applicability. Patent (CN215593986U) discloses a steel pipe anchor static pressure pile, which uses segmented pile sections and threaded sleeves to compress the soil. However, this technology does not have an extended load-bearing structure, and the single pile load-bearing capacity relies only on the pile side friction and pile end resistance, making it difficult to meet the load-bearing requirements in confined space scenarios; the segmented pressing of the pile sections still generates a soil squeezing effect, easily causing displacement of the surrounding soil; the installation and cutting process of the threaded sleeve increases the construction complexity and is not suitable for adjacent building areas that are sensitive to disturbance.

[0005] To address the above issues, there is an urgent need for a new type of pile foundation structure and construction method that can minimize the disturbance of construction to the surrounding environment while significantly improving the bearing capacity of a single pile. Summary of the Invention

[0006] Based on this, the purpose of the present invention is to provide a static pressure steel pipe pile with anchor rod in a confined space and a construction method thereof, so as to solve the technical problems mentioned in the background art.

[0007] To achieve the above objectives, the present invention provides the following technical solution: A micro-disturbance composite structure anchor static pressure steel pipe pile in a confined space includes a steel pipe pile body, deployable shear keys, shear key connecting rods, cement-soil reinforcement body, a central rotating rod, and a pile tip. The steel pipe pile body is composed of prefabricated high-strength standard steel pipe segments and a pile tip at the bottom. The standard steel pipe segments have pre-drilled holes in their walls. Multiple deployable shear keys are symmetrically arranged on the side walls of the steel pipe pile body. During pile insertion, they are in a retracted state and tightly adhere to the inner wall of the steel pipe pile body. After the pile body is in place, they unfold and penetrate the pre-drilled holes, embedding themselves into the surrounding cement-soil reinforcement body. The central rotating rod runs through the center of the steel pipe pile body and has a pre-drilled interface at the top for connection to a driving device. The shear key connecting rods, passing through the pre-drilled connection ports of the central rotating rod, connect to the central rotating rod, and their two ends are hinged to custom-designed track wheels on the deployable shear keys. The cement-soil reinforcement body is wrapped around the outside of the steel pipe pile body and is formed using a micro-disturbance jet grouting reinforcement process.

[0008] Furthermore, the diameter of the steel pipe pile body is not less than φ325, and the length of a single section of the standard steel pipe segment is 1m, 1.5m, 2m, 2.5m or 3m.

[0009] Furthermore, the multiple deployable shear keys are spaced 500mm apart vertically along the steel pipe pile body, and adjacent deployable shear keys are arranged vertically staggered. The deployable shear keys are made of steel plates with a thickness of 8~12mm, cut into an approximate fan-shaped structure.

[0010] Furthermore, the deployable shear key is equipped with a customized track wheel, and the deployable shear key has an arc-shaped elongated groove corresponding to the curvature of the steel pipe pile body. The customized track wheel can slide directionally along the arc-shaped elongated groove.

[0011] Furthermore, the deployable shear key is provided with an elongated oval hole, and a fixing pin is welded to the inner wall of the steel pipe pile. The fixing pin is hinged to the elongated oval hole to limit the radial displacement range of the deployable shear key.

[0012] Furthermore, the central rotating rod is made of a steel pipe with a thickness of 20mm and a diameter of 100mm, and a connection port adapted to the shear key connecting rod is provided at a preset position on the rod body.

[0013] Furthermore, the upper and lower sections of the central rotating rod are quickly connected using a pin-type self-locking connection mechanism.

[0014] Furthermore, the cement-soil reinforcement body is constructed using the MJS method, with a diameter 1 to 1.5 times that of the steel pipe pile body. The steel pipe pile body is driven into the pile before the initial setting of the cement-soil reinforcement body.

[0015] A construction method for a micro-disturbance composite structure anchored static pressure steel pipe pile in a confined space, using the aforementioned steel pipe pile, includes the following steps: S1: Construction of the micro-disturbance cement-soil reinforcement body, employing the MJS method of micro-disturbance cement-soil reinforcement technology, constructing the cement-soil reinforcement body under low clearance conditions, and achieving different pile diameters by adjusting water, air, and grout pressures; S2: Anchored static pressure pile driving construction, after the cement-soil reinforcement body construction is completed, using the foundation pit bottom slab or the constructed pile cap as a reaction support, the steel pipe pile body equipped with deployable shear keys and a central rotating member is slowly pressed into the cement-soil reinforcement body using an anchored static pressure device; S3: Deploying the shear keys to form a composite structure, after the pile body is pressed to the design elevation, ... A rotating device is installed on the top of the pile and connected to the reserved interface at the top of the central rotating rod. A torque is applied to rotate the central rotating rod. Through the linkage of the shear key connecting rods, the deployable shear key is pushed out from the reserved hole of the steel pipe pile and embedded inside the cement-soil reinforced body. S4: Curing and subsequent construction: Maintain the state of the pile body and the deployable shear key until the cement-soil reinforced body is completely cured, so that the pile body, the deployable shear key and the cement-soil reinforced body form an integral composite structure, and then carry out the subsequent process of sealing the pile head.

[0016] Furthermore, in step S3, the rotating device is a hydraulic wrench or an electric torque wrench, and the rotating device is detachably connected to the reserved interface of the central rotating rod through an adapter connector.

[0017] Compared with the prior art, the present invention has the following significant advantages: 1. Significantly reduces construction disturbance: First, a cement-soil solid is formed, and then static pressure pile driving is carried out in the plastic body. This fundamentally avoids the strong soil squeezing effect of traditional static pressure piles and realizes true "micro-disturbance" construction, which is particularly suitable for deformation-sensitive environments.

[0018] 2. Significantly improves the bearing capacity of a single pile: The deployable shear key forms a strong "root" effect after the pile is formed, which greatly increases the side resistance and end resistance of the pile, and its bearing capacity is much higher than that of traditional anchor static pressure piles of the same size.

[0019] 3. Ingenious structure and high reliability: The deployable mechanism has a simple structure, a clear force transmission path, and reliable operation, ensuring the final molding quality of the composite structure.

[0020] 4. Flexible construction and strong adaptability: This method inherits the advantages of small size of anchor static pressure pile equipment, and is very suitable for complex conditions such as reinforcement and renovation of existing buildings with limited working space and low headroom.

[0021] In summary, this invention cleverly solves the pain points of traditional processes through the innovative approach of "solidification before static pressure and pile formation before expansion," providing an efficient and reliable solution for foundation treatment and reinforcement in confined spaces. Attached Figure Description

[0022] Figure 1 This is a schematic diagram of the overall structure of the micro-disturbance composite anchor static pressure steel pipe pile of the present invention; Figure 2 This is a three-dimensional schematic diagram of a standard pipe segment of the micro-disturbance composite structure anchor static pressure steel pipe pile of the present invention; Figure 3 This is a schematic diagram of the shear key retraction state of a standard pipe segment of the micro-disturbance composite structure anchor static pressure steel pipe pile of the present invention; Figure 4 This is a schematic diagram of the unfolded state of the shear key in a standard pipe segment of the static pressure steel pipe pile with micro-disturbance composite structure anchor bolt according to the present invention; Figure 5 This is a schematic cross-sectional view of the shear key development state of a standard pipe segment of the static pressure steel pipe pile with micro-disturbance composite structure anchor bolt according to the present invention; In the diagram: 1. Standard steel pipe segment; 2. Cement-soil reinforced body; 3. Central rotating member; 4. Shear key; 5. Shear key connecting member; 6. Pin self-locking connection mechanism; 7. Pile tip; 8. Custom track wheel; 9. Arc-shaped elongated groove; 10. Fixing pin; 11. Elongated hole Detailed Implementation The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain the present invention, and should not be construed as limiting the present invention.

[0023] like Figures 1 to 5 As shown, this embodiment uses foundation reinforcement construction under confined space conditions as an application scenario to describe in detail the specific structure and parameters of a micro-disturbance composite structure anchor static pressure steel pipe pile and its construction method in a confined space: The present invention relates to a micro-disturbance composite structure anchor static pressure steel pipe pile in a confined space, comprising a steel pipe pile body, an expandable shear key 4, a shear key connecting rod 5, a cement-soil reinforced body 2, a central rotating rod 3, and a pile tip 7.

[0024] Furthermore, the steel pipe pile body is composed of prefabricated high-strength standard steel pipe segments 1 and a pile tip 7 at the bottom, and the pile diameter of the steel pipe pile body is not less than φ325.

[0025] Furthermore, multiple deployable shear keys 4 are symmetrically arranged on the sidewall of the steel pipe pile, with a vertical spacing of 500mm, and adjacent vertically staggered shear keys 4. During pile driving, the shear keys 4 are in a retracted state, closely adhering to the inner wall of the pile to reduce driving resistance. After the pile is in place, it can be deployed by a driving mechanism to penetrate the pile wall and embed itself into the surrounding cement-soil reinforcement.

[0026] Furthermore, the shear key connecting rod 5 is the core transmission rod, which passes through the reserved connection port of the central rotating rod 3 to connect with the central rotating rod 3 (similar to a pin connection), and its two ends are respectively connected to the hinge points of the customized track wheels 8 on the shear key 4. When the central rotating rod 3 rotates, it will drive the linkage mechanism to move, thereby converting the rotational motion of the central rod into the radial expansion (pull out of the pile wall) or retraction (pull back into the pile) motion of the shear key 3. Furthermore, the central rotating member 3 is installed along the entire length of the center of the steel pipe pile. It is a 20mm thick, 100mm diameter steel pipe component, with a pre-reserved interface at its top for connection to the drive device via other connectors. Connection ports for the shear key connecting members 5 at preset positions are provided on the member. The upper and lower sections are connected using a self-locking pin connection mechanism 6 for quick connection.

[0027] Furthermore, the cement-soil reinforcement body 2 is constructed using a micro-disturbance jet grouting reinforcement process to form a cylindrical cement-soil body. The MJS method is preferred, as micro-disturbance construction can be achieved even under low headroom conditions. The diameter of the cement-soil reinforcement body is selected based on the diameter of the steel pipe pile, and should preferably be 1 to 1.5 times the diameter of the steel pipe pile. The steel pipe pile body should be driven into the pile before the initial setting of the cement-soil reinforcement body 2.

[0028] Furthermore, the standard steel pipe segment 1 is a hollow cylinder, serving as the main force transmission component. The standard lengths of each segment are 1m, 1.5m, 2m, 2.5m, and 3m, respectively. The appropriate pipe segment length is selected based on the site clearance height, and the pipe wall is provided with reserved holes for the shear key 4 to extend and retract.

[0029] Furthermore, the shear key 4 is made of an 8-12mm thick steel plate cut into an approximately fan-shaped structure. An arc-shaped elongated oval groove 9 corresponding to the curvature of the steel pipe pile is provided on the steel plate to allow the customized track wheel 8 to move along the path of this groove, as well as an elongated oval hole 11 to limit the displacement of the shear key 4. A fixing pin 10 is provided on the inner wall of the steel pipe pile and is hinged to this hole.

[0030] A method for constructing a micro-disturbance composite structure anchored static pressure steel pipe pile in a confined space, comprising the following steps: S1: Construction of micro-disturbance cement-soil reinforced body 2. The cement-soil reinforced body 2 is constructed under low headroom conditions using the MJS method micro-disturbance cement-soil reinforcement technology. Different pile diameters are achieved by adjusting the water, air, and grout pressure.

[0031] S2: Anchor static pressure pile driving construction. After the cement-soil reinforcement body 2 is completed, the foundation pit bottom plate or the constructed pile cap is used as a reaction support. The steel pipe pile body equipped with internal components such as deployable shear key 4 and central rotating rod 3 is slowly pressed into the cement-soil reinforcement body through the anchor static pressure equipment.

[0032] S3: Unfold the shear key 4 to form a composite structure. After the pile body is pressed to the design elevation, install a rotating device (such as a hydraulic wrench) on the top of the pile and connect it to the pre-reserved interface at the top of the central rotating member 3. Apply torque to rotate the central member 3, and through the linkage of the shear key connecting member 5, smoothly push the shear key 4 out of the steel pipe pile wall, so that it is firmly embedded and locked inside the cement-soil reinforced body 2.

[0033] S4: Curing and subsequent construction: Maintain the condition until the cement-soil solidified body 2 is completely cured, so that the pile body, shear key 4 and cement-soil solidified body 2 form an integral composite structure, and then subsequent processes such as sealing the pile head can be carried out.

[0034] Although embodiments of the present invention have been shown and described, these specific embodiments are merely explanations of the invention and are not intended to limit it. The specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples. After reading this specification, those skilled in the art may make modifications, substitutions, and variations to the embodiments as needed without departing from the principles and spirit of the invention, but such modifications, substitutions, and variations are protected by patent law as long as they are within the scope of the claims of the present invention.

Claims

1. A micro-disturbance composite structure anchor rod static pressure steel pipe pile in a limited space, characterized in that, The system includes a steel pipe pile body, deployable shear keys, shear key connecting members, a cement-soil reinforced body, a central rotating member, and a pile tip. The steel pipe pile body is composed of prefabricated high-strength standard steel pipe segments and a pile tip at the bottom. Pre-drilled holes are provided in the walls of the standard steel pipe segments. Multiple deployable shear keys are symmetrically arranged on the side walls of the steel pipe pile body. During pile driving, they are in a retracted state, tightly adhering to the inner wall of the steel pipe pile body. After the pile body is in place, they unfold and penetrate the pre-drilled holes, embedding themselves into the surrounding cement-soil reinforced body. The central rotating member runs through the steel pipe pile body. The structure is designed with a continuous center and a reserved interface at the top for connection to the drive device. The shear key connecting rod passes through the reserved connection port of the central rotating rod and connects to it. Both ends are hinged to custom-designed track wheels on the deployable shear key. The cement-soil reinforcement body is wrapped around the outside of the steel pipe pile and is formed using a micro-disturbance jet grouting reinforcement process. Multiple deployable shear keys are spaced 500mm apart vertically along the steel pipe pile, with adjacent deployable shear keys vertically staggered. The deployable shear keys have a thickness of 8-12mm. The steel plate is cut into an approximately fan-shaped structure; the deployable shear key is equipped with a custom track wheel, and the deployable shear key has an arc-shaped elongated groove corresponding to the curvature of the steel pipe pile body. The custom track wheel can slide directionally along the arc-shaped elongated groove; the deployable shear key also has an elongated hole, and a fixing pin is welded to the inner wall of the steel pipe pile body. The fixing pin is hinged to the elongated hole to limit the radial displacement range of the deployable shear key.

2. The micro-disturbance composite structure anchor rod static pressure steel pipe pile in a limited space according to claim 1, characterized in that, The diameter of the steel pipe pile body is not less than φ325, and the length of a single section of the standard steel pipe segment is 1m, 1.5m, 2m, 2.5m or 3m.

3. The micro-disturbance composite structure anchor rod static pressure steel pipe pile in a limited space according to claim 1, characterized in that, The central rotating member is a steel pipe component with a thickness of 20mm and a diameter of 100mm. The member has a connection port at a preset position that is compatible with the shear key connecting member.

4. The slightly disturbed composite structure jacked pile in confined space of claim 3, wherein, The upper and lower sections of the central rotating rod are quickly connected by a self-locking pin connection mechanism.

5. The slightly disturbed composite structure jacked pile in confined space of claim 1, wherein, The cement-soil reinforced body is constructed using the MJS method, with a diameter 1 to 1.5 times that of the steel pipe pile. The steel pipe pile is driven into place before the cement-soil reinforced body initially sets.

6. A construction method of a micro-disturbance composite structure anchor rod static pressure steel pipe pile in a limited space, characterized in that, Using the steel pipe piles described in any one of claims 1 to 5, Includes the following steps: S1: Construction of the micro-disturbance cement-soil reinforced body, employing the MJS method for micro-disturbance cement-soil reinforcement. The cement-soil reinforced body is constructed under low headroom conditions, with different pile diameters achieved by adjusting water, air, and grout pressures. S2: Anchor bolt static pressure pile driving construction. After the cement-soil reinforced body construction is completed, the foundation pit bottom slab or the constructed pile cap serves as a reaction support. Anchor bolt static pressure equipment is used to slowly press steel pipe piles equipped with deployable shear keys and central rotating members into the cement-soil reinforced body. S3: Deploying the shear keys to form a composite structure, the pile... After the pile body is pressed to the design elevation, a rotating device is installed on the top of the pile and connected to the reserved interface at the top of the central rotating member. A torque is applied to rotate the central rotating member. Through the linkage of the shear key connecting members, the deployable shear key is pushed out from the reserved hole of the steel pipe pile and embedded into the cement-soil reinforced body. S4: Curing and subsequent construction: Maintain the state of the pile body and the deployable shear key until the cement-soil reinforced body is completely cured, so that the pile body, the deployable shear key and the cement-soil reinforced body form an integral composite structure, and then carry out the subsequent process of sealing the pile head.

7. The construction method according to claim 6, characterized in that, In step S3, the rotating device is a hydraulic wrench or an electric torque wrench, and the rotating device can be detachably connected to the reserved interface of the central rotating rod through the adapter connector.

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