Non-uniform geological pile foundation rotary excavating drill bit and construction method

Abstract

A drill rod (4) is of a hollow structure, an inner drill rod (3) is arranged in the center of the drill rod (4), a drill bit is arranged at the lower end of the inner drill rod (3), the inner drill rod (3) can drill in the axial direction relative to the drill rod (4), a hole is formed in the center of the lower end face of a drill barrel (2) to serve as an inlet and outlet channel of the inner drill rod (3), and the drill rod (4) is connected with the drill barrel (2). When the drill cylinder drills to the interface of the soft and hard geology, the drill cylinder can be stopped, the drill cylinder is used as a positioning part, the small drill bit is used for firstly drilling through the hard bottom layer, then the small drill bit is used as the positioning part of the drill cylinder to enable the drill cylinder to drill downwards to the preset depth, and therefore the deviation of the drill bit when the drill bit penetrates through the interface of the soft and hard geology can be greatly reduced.

Description

Technical Field

[0001] The invention relates to a rotary drilling machine drill bit and a method for constructing uneven geology by using the drill bit. Background Art

[0002] When the fertilizer trough of the foundation pit with slope support is backfilled and rotary drilling is required in this area, the drill barrel of the rotary drilling rig will first touch the concrete support structure of the foundation pit slope support on one side during the digging process, while the backfill soil layer on the other side is relatively soft. As the rotary drilling bit continues to dig, the side close to the concrete support structure is subject to repulsive force, which will cause the drill barrel to shift to one side of the backfill soil layer, thereby making the pile hole eccentric, affecting the verticality of the hole pile and thus affecting the quality of the pile foundation. Summary of the invention

[0003] Aiming at the problem that the drill tube of a rotary drilling machine may deviate at the interface between soft and hard geology, the present invention provides a drill bit structure of a rotary drilling machine with segmented drilling and a corresponding construction method.

[0004] The technical solution of the present invention: A rotary drilling drill bit for pile foundation in uneven geology comprises a drill rod 4 and a drill barrel 2. The drill rod 4 is a hollow structure. An inner drill rod 3 is arranged at the center of the drill rod 4. A drill bit is arranged at the lower end of the inner drill rod 3. The inner drill rod 3 can be drilled axially relative to the drill rod 4. A hole is opened in the center of the lower end surface of the drill barrel 2 as an entry and exit channel for the inner drill rod 3. The drill rod 4 is connected to the drill barrel 2.

[0005] An outer sleeve 5 is disposed outside the drill rod 4 . The outer sleeve 5 is connected to the outer cylinder 1 . The drill cylinder 2 is located inside the outer cylinder 1 .

[0006] The lower end surface of the outer tube 1 is provided with a circle of drill teeth, and the lower end of the drill tube 2 is provided with a row of drill teeth.

[0007] A steering mechanism 6 is installed at the power input end of the outer casing 5 and the drill rod 4 to make the outer casing 5 and the drill rod 4 rotate in opposite directions.

[0008] The steering mechanism 6 is composed of three bevel gears, which are respectively mounted on the outer casing 5, the drill rod 4 and the bracket.

[0009] A rotary drilling construction method for pile foundation in uneven geology, using the above-mentioned rotary drilling drill bit, first retracting the inner drill rod 3, using the drill tube 2 to dig to the interface of the uneven geology; then controlling the drill tube 2 to stop rotating and drilling, starting the inner drill rod 3 to dig to a predetermined depth and then stopping; finally starting the drill tube 2 to dig to a predetermined position.

[0010] The interface of the uneven geology refers to the interface between the backfill soil and the concrete pit foundation support structure. When the edge of the drill tube 2 reaches the concrete layer, it stops descending, and then the inner drill rod 3 is used to continue digging into the concrete layer, and finally the drill tube 2 is started to dig.

[0011] Beneficial effects of the present invention: A small retractable rotating head is added to the drill tube. When the drill tube reaches the interface between soft and hard geology, the drill tube can be stopped, and the small drill bit is used to drill through the hard bottom layer first, and then the small drill bit is used to position the drill tube to drill down to the predetermined depth. This can greatly reduce the deviation of the drill bit when crossing the interface between soft and hard geology. The drill tube is designed as an inner and outer double drill tube structure, and the inner and outer tubes rotate in opposite directions, which further improves the stability of the drill tube in drilling uneven geology. BRIEF DESCRIPTION OF THE DRAWINGS

[0012] Figure 1 It is a three-dimensional perspective structural diagram of the drill barrel (drill rod retracted).

[0013] Figure 2 It is a three-dimensional schematic diagram of the drill barrel when the drill rod is extended.

[0014] Figure 3 This is a schematic diagram of the first excavation depth during construction.

[0015] Figure 4 This is a schematic diagram of the second deepening position during construction.

[0016] Figure 5 It is a schematic diagram of the three-layer drill pipe structure. DETAILED DESCRIPTION

[0017] Embodiment 1: In this embodiment, the drill rod 4 and the drill barrel 2 are structurally improved. The drill rod 4 is made into a hollow structure, an inner drill rod 3 is added in the center thereof, and a hole is opened in the center of the lower end surface of the drill barrel 2 as an inlet and outlet passage for the inner drill rod 3. The drill rod 4 and the drill barrel 2 are connected as one body, and the inner drill rod 3 can be retracted into the drill barrel 2 or extended out of the drill barrel 2. A high-hardness spiral drill bit is installed at the lower end of the inner drill rod 3. The lower end surface of the drill barrel 2 also has a row of drill teeth, and the side of the row of drill teeth has two flip cover plates.

[0018] The specific construction method is shown in the figure. It is necessary to rotary dig a pile foundation hole in the backfilled soil foundation pit. The hole needs to pass through the backfill soil layer and the concrete layer in turn. The interface between the two is an inclined surface. The specific construction steps are as follows: The drill tube 2 is controlled to dig downward until the edge of the drill tube 2 reaches the concrete layer, at which time the movement of the drill tube 2 is stopped. The inner drill rod 3 is started to continue drilling downward until the drill rod 3 drills into the concrete layer to a certain depth, and then the drill rod 3 is stopped. The drill tube 2 is started to continue to rotate downward, and during this process, the drill rod 3 can be used as a positioning structure to prevent the drill tube from deviating. Example 2: This embodiment further transforms the drill rod 4 and the drill tube 2 on the basis of the embodiment 1, and makes the drill rod 4 into a three-layer structure, with an inner drill rod inside the drill rod 4 and an outer sleeve 5 outside. At the same time, an outer sleeve 1 is also added outside the drill tube 2. A steering mechanism 6 is installed at the power input end of the drill rod 4, such as Figure 5 As shown, the steering mechanism 6 is composed of three bevel gears, which are respectively mounted on the outer sleeve 5, the drill rod 4 and the bracket, so that the drill rod 4 and the outer sleeve 5 can rotate in opposite directions. The outer cylinder 1 and the outer sleeve 5 are connected as a whole and rotate synchronously, and the drill cylinder 2 and the drill rod 4 are connected as a whole and rotate synchronously, so that the outer cylinder 1 and the drill cylinder 2 can rotate synchronously in the opposite direction, preventing the rotating cylinder from deflecting in one direction when touching the hard layer, and improving the overall stability. The lower end surface of the outer cylinder 1 has a circle of drill teeth.

[0019] The above-mentioned embodiments only express several implementation methods of the present invention, and the description thereof is relatively specific and detailed, but it cannot be understood as limiting the scope of the patent of the present invention. It should be pointed out that, for ordinary technicians in this field, several variations and improvements can be made without departing from the concept of the present invention, which all belong to the protection scope of the present invention. Therefore, the protection scope of the patent of the present invention shall be subject to the attached claims.

Claims

1. A rotary drilling drill bit for pile foundation in uneven geology, comprising a drill rod (4) and a drill barrel (2), characterized in that: The drill rod (4) is a hollow structure. An inner drill rod (3) is arranged at the center of the drill rod (4). A drill bit is arranged at the lower end of the inner drill rod (3). The inner drill rod (3) can be drilled axially relative to the drill rod (4). A hole is opened at the center of the lower end surface of the drill tube (2) as an inlet and outlet passage for the inner drill rod (3). The drill rod (4) and the drill tube (2) are connected.

2. The uneven geological pile foundation rotary drilling drill bit according to claim 1, characterized in that: An outer sleeve (5) is provided outside the drill rod (4), the outer sleeve (5) is connected to the outer cylinder (1), and the drill cylinder (2) is located inside the outer cylinder (1).

3. The uneven geological pile foundation rotary drilling drill bit according to claim 2, characterized in that: The lower end surface of the outer cylinder (1) is provided with a circle of drill teeth.

4. The uneven geological pile foundation rotary drilling drill bit according to claim 2, characterized in that: A steering mechanism (6) is installed at the power input ends of the outer casing (5) and the drill rod (4) to make the outer casing (5) and the drill rod (4) rotate in opposite directions.

5. The uneven geological pile foundation rotary drilling drill bit according to claim 4, characterized in that: The steering mechanism (6) is composed of three bevel gears, which are respectively mounted on the outer casing (5), the drill rod (4) and the bracket.

6. A method for rotary drilling construction of pile foundation in uneven geology, using the rotary drilling drill bit according to any one of claims 1 to 5, characterized in that: Firstly, the inner drill rod (3) is retracted, and the drill tube (2) is used to dig down to the interface of uneven geology; then the drill tube (2) is controlled to stop rotating and drilling, and the inner drill rod (3) is started to dig down to a predetermined depth and then stops moving; finally, the drill tube (2) is started to dig down to a predetermined position.

7. The method for rotary drilling of pile foundation in uneven geology according to claim 6, characterized in that: The interface of the uneven geology refers to the interface between the backfill soil and the concrete pit foundation support structure. When the edge of the drill tube (2) reaches the concrete layer, it stops descending, and then the inner drill rod (3) is used to continue digging into the concrete layer, and finally the drill tube (2) is started to dig.

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