A hole forming device and a hole forming method for concrete bored cast-in-place threaded pile

Abstract

A hole-forming device and a hole-forming method for a concrete bored cast-in-place threaded pile, comprising a core rod, a sleeve rod, a sleeve rod threaded wall, a sleeve rod threaded wall driving device, a core rod threaded wall and a core rod threaded wall driving device; the sleeve rod is sleeved on the core rod, and the sleeve rod can slide axially along the core rod; the sleeve rod threaded wall is arranged on the outside of the sleeve rod, and the sleeve rod and the sleeve rod threaded wall are connected by the sleeve rod threaded wall driving device; the core rod threaded wall is arranged on the outside of the core rod, and the core rod threaded wall and the core rod are connected by the core rod threaded wall driving device; the sleeve rod threaded wall and the core rod threaded wall can surround a complete threaded column. In the process of bored cast-in-place pile construction, after the conventional straight-wall bored cast-in-place pile is bored, the hole wall is squeezed to form a threaded shape, and the lateral friction resistance between the pile and the soil is increased, so as to achieve the purpose of improving the bearing capacity of the pile foundation under the premise of unchanged pile diameter, or when the same bearing capacity requirement is required, the pile diameter or pile length can be reduced to achieve the purpose of saving engineering cost.

Description

Technical Field

[0001] The invention relates to the field of bored cast-in-place piles in pile foundation engineering, and in particular to a hole-forming device and a hole-forming method for concrete bored cast-in-place threaded piles. Background Art

[0002] In pile foundation engineering, bored piles are divided into end-bearing piles and friction piles according to their stress characteristics. The bearing capacity of end-bearing piles mainly comes from the resistance of the solid soil layer or bedrock at the pile end; the bearing capacity of friction piles mainly comes from the lateral friction resistance between the pile body and the soil. After the bored pile is bored, the hole wall is squeezed into a threaded shape to increase the lateral friction resistance between the pile and the soil, which can improve the bearing capacity of the friction pile. At present, concrete threaded piles are mainly prefabricated piles. Torque is applied to the pile body to squeeze it into the soil. The torque that the pile body can withstand is limited by the strength of the concrete, and the pile diameter and pile length are relatively small. Summary of the invention

[0003] The object of the present invention is to provide a hole-forming device and a hole-forming method for concrete bored cast-in-place threaded piles to solve the above-mentioned problems.

[0004] To achieve the above object, the present invention adopts the following technical solutions:

[0005] A hole-forming device for concrete bored and cast-in-place threaded piles comprises a core rod, a sleeve rod, a sleeve rod threaded wall, a sleeve rod threaded wall driving device, a core rod threaded wall and a core rod threaded wall driving device; the sleeve rod is sleeved on the core rod, and the sleeve rod can slide axially along the core rod; the sleeve rod threaded wall is arranged on the outside of the sleeve rod, and the sleeve rod and the sleeve rod threaded wall are connected by the sleeve rod threaded wall driving device; the core rod threaded wall is arranged on the outside of the core rod, and the core rod threaded wall and the core rod are connected by the core rod threaded wall driving device; the sleeve rod threaded wall and the core rod threaded wall can surround a complete threaded column.

[0006] Furthermore, the sleeve rod thread wall driving device includes four sleeve rod bidirectional hydraulic cylinders, which are divided into two groups and symmetrically arranged on both sides of the sleeve rod. The output ends of the sleeve rod bidirectional hydraulic cylinders are connected to the sleeve rod thread wall.

[0007] Furthermore, the output directions of the two sleeve rod bidirectional hydraulic cylinders on the same side intersect; and the two ends of the sleeve rod bidirectional hydraulic cylinder are hinged to the sleeve rod and the sleeve rod threaded wall respectively.

[0008] Furthermore, the core rod thread wall driving device includes four core rod bidirectional hydraulic cylinders, which are divided into two groups and symmetrically arranged on both sides of the core rod. The output ends of the core rod bidirectional hydraulic cylinders are connected to the core rod thread wall.

[0009] Furthermore, the output directions of the two bidirectional hydraulic cylinders of the core rod on the same side intersect; and the two ends of the bidirectional hydraulic cylinder of the core rod are hinged to the core rod and the threaded wall of the core rod respectively.

[0010] Furthermore, two symmetrical axial grooves are provided on the side wall of the sleeve rod, and a limiting cap is provided at one end of the sleeve rod.

[0011] Furthermore, a limiting block matching the limiting cap is arranged in the middle of the core rod.

[0012] Furthermore, the sleeve rod threaded wall and the core rod threaded wall are two threaded walls with the same structure. When the limiting cap and the limiting block are in contact, the two sleeve rod threaded walls and the two core rod threaded walls form a complete threaded column.

[0013] Furthermore, the threads on the surface of the threaded column are continuous threads.

[0014] Furthermore, a method for forming a hole for a concrete bored cast-in-place threaded pile comprises the following steps:

[0015] The sleeve rod is lifted up, so that the thread wall of the sleeve rod and the thread wall of the core rod are staggered up and down;

[0016] Contracting the bidirectional hydraulic cylinder brings the threaded wall of the sleeve rod and the threaded wall of the core rod into a retracted state;

[0017] After the conventional straight-wall bored pile hole is formed, the device is lowered to the bottom of the hole or to the set depth. The inner diameter of the selected device should be the same as the hole diameter of the conventional bored pile.

[0018] Extend the bidirectional hydraulic cylinder on the core rod, so that the thread wall of the core rod can be expanded under the action of the upper and lower guide grooves and the hydraulic cylinder;

[0019] Lower the sleeve rod to the bottom, so that the sleeve rod thread wall is expanded under the action of the upper and lower guide grooves and the hydraulic cylinder to form an integral structure with the thread wall of the core rod;

[0020] Rotate and lift upward along the thread direction. The rotation and lifting speed should ensure that there is no vertical relative displacement between the screw thread formed on the hole wall and the soil around the pile.

[0021] When rotating and lifting to the hole mouth or set height, first retract the threaded wall of the sleeve rod and lift the sleeve rod, then retract the threaded wall of the core rod, and finally lift out the pile hole to complete the hole-making work of the concrete bored pile.

[0022] Compared with the prior art, the present invention has the following technical effects:

[0023] The sleeve rod of the present invention can move up and down on the core rod, the sleeve rod thread wall is connected to the sleeve rod through a two-way hydraulic oil cylinder, and the core rod thread wall is connected to the core rod through a two-way hydraulic oil cylinder. The contraction and extension of the thread wall are achieved through the extension and contraction of the hydraulic oil cylinder and the guide grooves on the core rod and the sleeve rod. In the construction process of bored cast-in-place piles, after the conventional straight-wall bored cast-in-place pile is bored, the device is used to rotate and lift from the bottom of the pile hole to the hole mouth, forming a threaded structure on the hole wall, increasing the lateral friction resistance between the pile and the soil, thereby achieving the purpose of improving the pile foundation bearing capacity under the premise of unchanged pile diameter, or reducing the pile diameter or pile length when the same bearing capacity requirements are required, thereby achieving the purpose of saving engineering costs. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 The overall schematic diagram of the present invention;

[0025] Figure 2 Axonometric drawing of sleeve rod

[0026] Figure 3 Axonometric drawing of core rod

[0027] Figure 4 Combination diagram of sleeve rod and core rod

[0028] Figure 5 Axonometric drawing of the threaded wall of the sleeve

[0029] Figure 6 Axonometric drawing of the thread wall of the core rod

[0030] Figure 7 During use: the device is fully folded

[0031] Figure 8 During use: the thread wall of the core rod stretches

[0032] Fig. 9 The device is about to be fully extended during use

[0033] Fig.10 The device is fully extended during use

[0034] Among them: 1 is a central rod; 2 is a sleeve rod; 3 is a sleeve rod thread wall; 4 is a sleeve rod bidirectional hydraulic cylinder; 5 is a central rod thread wall; 6 is a central rod bidirectional hydraulic cylinder; 11 is a limit cap; 21 is a limit block. DETAILED DESCRIPTION

[0035] The present invention is further described below in conjunction with the accompanying drawings:

[0036] See also Figures 1 to 9 The object of the present invention is to provide a drilling device and a drilling method for concrete bored cast-in-place threaded piles, which can improve the bearing capacity without changing the pile diameter and pile length, or can reasonably reduce the pile diameter and pile length while meeting the bearing capacity requirements, thereby saving engineering costs.

[0037] The present invention adopts the following technical scheme: the hole-forming device is divided into a core rod, a sleeve rod, a sleeve rod threaded wall, a core rod threaded wall and an underwater two-way hydraulic cylinder and other main components. The sleeve rod can move up and down on the core rod, the sleeve rod threaded wall is connected to the sleeve rod through a two-way hydraulic cylinder, and the core rod threaded wall is connected to the core rod through a two-way hydraulic cylinder. The contraction and extension of the threaded wall are achieved through the extension and retraction of the hydraulic cylinder and the constraint of the guide grooves on the core rod and the sleeve rod.

[0038] See also Figure 1 The present invention relates to a hole-forming device and method for bored cast-in-place concrete threaded piles. During the construction process, on the basis of conventional bored cast-in-place pile hole-forming, the device is folded up, lowered to the bottom of the hole, stretched at the bottom of the hole, and then rotated and lifted to the pile mouth or a set height to squeeze the cylindrical hole wall into a threaded shape. During the process, the rotation and lifting speeds should ensure that the screw teeth formed on the hole wall and the soil around the pile do not produce vertical relative displacement. After rotating and lifting out of the hole mouth, the steel cage is lowered to cast concrete or concrete is directly cast to form a concrete threaded pile.

[0039] The method of using the present invention is further described in detail below:

[0040] During the construction of concrete bored cast-in-place threaded piles, the specific method of using this device is as follows:

[0041] ① Lift the sleeve rod upwards so that the thread wall of the sleeve rod and the thread wall of the core rod are staggered up and down;

[0042] ② Contract the bidirectional hydraulic cylinder to bring the threaded wall of the sleeve rod and the threaded wall of the core rod into a closed state;

[0043] ③ After the conventional straight-wall bored pile hole is formed, the device is lowered to the bottom of the hole or the set depth. The inner diameter of the selected device should be the same as the hole diameter of the conventional bored pile; the inner diameter of the selected device is the diameter of the column formed after removing the thread.

[0044] ④ Extend the bidirectional hydraulic cylinder on the core rod to expand the thread wall of the core rod under the action of the upper and lower guide grooves and the hydraulic cylinder;

[0045] ⑤ Lower the sleeve rod to the bottom, so that the sleeve rod thread wall is expanded under the action of the upper and lower guide grooves and the hydraulic cylinder to form an integral structure with the thread wall of the core rod;

[0046] ⑥ Rotate and lift upward along the thread direction. The rotation and lifting speed should ensure that there is no vertical relative displacement between the screw thread formed on the hole wall and the soil around the pile;

[0047] ⑦ When rotating and lifting to the hole mouth or set height, first retract the threaded wall of the sleeve rod and lift the sleeve rod, then retract the threaded wall of the core rod, and finally lift the pile hole to complete the hole-making work of the concrete bored and cast-in-place threaded pile.

Claims

1. A hole-forming device for concrete bored and cast-in-place threaded piles, characterized in that: The invention comprises a core rod (1), a sleeve rod (2), a sleeve rod threaded wall (3), a sleeve rod threaded wall driving device, a core rod threaded wall (5) and a core rod threaded wall driving device; the sleeve rod (2) is sleeved on the core rod (1), and the sleeve rod (2) can slide axially along the core rod (1); the sleeve rod threaded wall (3) is arranged outside the sleeve rod (2), and the sleeve rod (2) and the sleeve rod threaded wall (3) are connected via the sleeve rod threaded wall driving device; the core rod threaded wall (5) is arranged outside the core rod (1), and the core rod threaded wall (5) and the core rod (1) are connected via the core rod threaded wall driving device; the sleeve rod threaded wall (3) and the core rod threaded wall (5) can enclose a complete threaded column; Two symmetrical axial grooves are provided on the side wall of the sleeve rod (2), and a limiting cap (21) is provided at one end of the sleeve rod (2); A limiting block (11) matching the limiting cap is arranged in the middle of the core rod (1); The sleeve rod thread wall driving device comprises four sleeve rod bidirectional hydraulic oil cylinders, which are divided into two groups and symmetrically arranged on both sides of the sleeve rod (2). The output ends of the sleeve rod bidirectional hydraulic oil cylinders are connected to the sleeve rod thread wall (3).

2. A hole-forming device for bored concrete threaded piles according to claim 1, characterized in that: The output directions of the two sleeve rod bidirectional hydraulic oil cylinders on the same side intersect; the two ends of the sleeve rod bidirectional hydraulic oil cylinder are respectively hinged to the sleeve rod (2) and the sleeve rod threaded wall (3).

3. A hole-making device for bored concrete threaded piles according to claim 1, characterized in that: The core rod thread wall driving device comprises four core rod bidirectional hydraulic oil cylinders, which are divided into two groups and symmetrically arranged on both sides of the core rod (1). The output ends of the core rod bidirectional hydraulic oil cylinders are connected to the core rod thread wall (5).

4. A hole-forming device for concrete bored cast-in-place threaded piles according to claim 3, characterized in that: The output directions of the two central rod bidirectional hydraulic cylinders on the same side intersect; the two ends of the central rod bidirectional hydraulic cylinder are respectively hinged to the central rod (1) and the central rod threaded wall (5).

5. A hole-forming device for bored concrete threaded piles according to claim 1, characterized in that: The sleeve rod threaded wall (3) and the core rod threaded wall (5) are both two threaded walls with the same structure. When the limiting cap and the limiting block (11) are in contact, the two sleeve rod threaded walls (3) and the two core rod threaded walls (5) form a complete threaded column.

6. A hole-making device for bored concrete threaded piles according to claim 1, characterized in that: The threads on the surface of the threaded column are continuous threads.

7. A method for drilling concrete bored cast-in-place threaded piles, characterized in that: The hole-making device for bored concrete threaded piles according to any one of claims 1 to 6 comprises the following steps: The sleeve rod is lifted up, so that the thread wall of the sleeve rod and the thread wall of the core rod are staggered up and down; Contracting the bidirectional hydraulic cylinder brings the threaded wall of the sleeve rod and the threaded wall of the core rod into a retracted state; After the conventional straight-wall bored pile hole is formed, the device is lowered to the bottom of the hole or to the set depth. The inner diameter of the selected device should be the same as the hole diameter of the conventional bored pile. Extend the bidirectional hydraulic cylinder on the core rod, so that the thread wall of the core rod can be expanded under the action of the upper and lower guide grooves and the hydraulic cylinder; Lower the sleeve rod to the bottom, so that the sleeve rod thread wall is expanded under the action of the upper and lower guide grooves and the hydraulic cylinder to form an integral structure with the thread wall of the core rod; Rotate and lift upward along the thread direction. The rotation and lifting speed should ensure that there is no vertical relative displacement between the thread teeth formed on the hole wall and the soil around the pile. When rotating and lifting to the hole mouth or set height, first retract the threaded wall of the sleeve rod and lift the sleeve rod, then retract the threaded wall of the core rod, and finally lift out the pile hole to complete the hole-making work of the concrete bored and cast-in-place threaded pile.

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