A method for variable-diameter pile hole construction suitable for deep and large-grain pebble geology

Abstract

The application discloses a variable-diameter pile hole construction method suitable for deep and thick large-granularity pebble geology, adopts a rotary drilling machine to perform variable-diameter pile hole construction, the variable-diameter pile hole comprises coaxially arranged large-diameter pile holes and small-diameter pile holes, an integrated drill bit is arranged at the bottom of a drill rod of the rotary drilling machine, the integrated drill bit comprises a large-diameter drill bit for drilling the large-diameter pile holes and a small-diameter drill bit for drilling the small-diameter pile holes; when the large-diameter pile holes are drilled, the large-diameter drill bit is arranged outside the small-diameter drill bit, and the two are fixedly connected with the bottom of the drill rod; when the small-diameter pile holes are drilled, the large-diameter drill bit is fixed on the drill rod through a sliding clamp to guide the drill rod. The application can guarantee coaxial arrangement of the large-diameter pile holes and the small-diameter pile holes of the variable-diameter pile, protect the thickness of the reinforcing steel bar protective layer of the reinforcing cage, and does not need to replace the drill bit back and forth during construction, so that the construction efficiency is high.

Description

Technical Field

[0001] This invention relates to the field of variable diameter pile construction. More specifically, this invention relates to a method for constructing variable diameter pile holes suitable for deep, large-diameter pebble geology. Background Technology

[0002] With the development of engineering construction in my country, variable diameter pile foundations are increasingly used in large buildings due to their high bearing capacity, small settlement, and low cost per unit force. Generally, the construction of variable diameter piles in pebble layers involves first using a crawler crane with a vibratory hammer to lower a steel casing through the pebble layer, and then changing the drill bit to complete the pile hole drilling. However, when constructing variable diameter piles in deep, large-diameter pebble geology, the following problems arise: the drill bit needs to be changed during pile foundation construction; there is severe eccentricity at the cross-section, making it difficult to lower the reinforcing cage; and the protective layer of the reinforcing cage is too thin. Furthermore, the steel casing needs to be lowered in sections using larger specialized equipment, resulting in low efficiency and high cost. Summary of the Invention

[0003] One object of the present invention is to solve at least the above-mentioned problems and to provide at least the advantages that will be described later.

[0004] To achieve these objectives and other advantages according to the present invention, a method for constructing variable-diameter pile holes suitable for deep, large-diameter pebble geology is provided. The method employs a rotary drilling rig for pile hole construction. The variable-diameter pile holes include a large-diameter pile hole and a small-diameter pile hole coaxially arranged from top to bottom. An integrated drill bit is installed at the bottom of the drill rod of the rotary drilling rig. The integrated drill bit includes a large-diameter drill bit for drilling the large-diameter pile hole and a small-diameter drill bit for drilling the small-diameter pile hole. When drilling the large-diameter pile hole, the large-diameter drill bit is sleeved outside the small-diameter drill bit, and both are fixedly connected to the bottom of the drill rod. When drilling the small-diameter pile hole, the large-diameter drill bit is fixed to the drill rod by a sliding clamp to guide the drill rod.

[0005] Preferably, it includes the following steps:

[0006] S1. Install the integrated drill bit at the bottom of the drill rod, wherein the top of the small-diameter drill bit is detachably connected to the bottom of the drill rod; the sliding clamp is fixedly connected to the top of the large-diameter drill bit, and the sliding clamp is detachably connected to the bottom of the drill rod.

[0007] S2. Drill to the designed position using the large-diameter drill bit and install the outer casing; after the outer casing is installed, disconnect the sliding clamp from the bottom of the drill rod.

[0008] S3. After the sliding clamp and the large-diameter drill bit are moved to the corresponding position on the drill rod by the traction device, the sliding clamp is clamped to the drill rod.

[0009] S4. Lower the drill rod and drill through the small-diameter drill bit to the bottom of the pebble layer, and install the inner casing;

[0010] S5. Drill downwards to the designed pile bottom using the small-diameter drill bit to complete the pile foundation construction;

[0011] In step S3, the corresponding positions of the sliding clamp and the large-diameter drill bit on the drill rod are as follows: during the downward drilling process of the small-diameter drill bit, the sliding clamp and the large-diameter drill bit are located above the diameter change point of the variable-diameter pile hole.

[0012] Preferably, during the downward drilling process of the small-diameter drill bit, the position of the sliding clamp and the large-diameter drill bit on the drill rod is adjusted by the traction device, and the sliding clamp is used to clamp or release the drill rod so that the sliding clamp and the large-diameter drill bit are always kept 30-40cm above the diameter change point of the variable-diameter pile hole.

[0013] Preferably, during the upward lifting of the drill rod, the sliding clamp is loosened, and the positions of the sliding clamp and the large-diameter drill bit are adjusted by the traction device so that they maintain a certain distance from the power head of the rotary drilling rig.

[0014] Preferably, the sliding clamp includes a fixed clamp and a movable clamp, which can clamp the drill rod after being connected; the bottom surface of the fixed clamp is fixedly connected to the top surface of the large-diameter drill bit, and the movable clamp is slidably connected to the top surface of the large-diameter drill bit.

[0015] Preferably, the sliding clamp further includes a driving device, and both ends of the fixed clamp and the movable clamp are provided with connecting blocks extending in the horizontal direction. The driving device is provided on the connecting blocks at both ends of the fixed clamp, and the driving device is used to drive the movable clamp to move closer to or away from the fixed clamp.

[0016] Preferably, the driving device includes a drive motor, a lead screw, and a lead screw slider. The drive motor is fixedly connected to the connecting block of the fixed band, and its output end is fixedly connected to the lead screw. The lead screw slider is fitted onto the lead screw and is fixedly embedded in the connecting block of the movable band.

[0017] Preferably, the sliding clamp includes a plurality of compensation devices spaced apart along the inner wall of the sliding clamp. Each compensation device includes an elastic pressure plate and a compression spring. The two ends of the elastic pressure plate are fixedly connected to the inner wall of the sliding clamp. One end of the compression spring is fixedly connected to the interior of the sliding clamp, and the other end is fixedly connected to the middle of the elastic pressure plate.

[0018] Preferably, the traction device is a winch, which is fixedly mounted on the rotary drilling rig, and the wire rope of the winch is fixedly connected to the top of the sliding clamp.

[0019] The present invention has at least the following beneficial effects:

[0020] 1. The method for constructing variable-diameter pile holes in deep, large-diameter pebble geology provided by this invention uses an integrated drill bit. When drilling a small-diameter pile hole, the large-diameter drill bit of the integrated drill bit is positioned above the diameter change point of the variable-diameter pile hole to guide the drill rod, ensuring that the large-diameter pile hole and the small-diameter pile hole are coaxially arranged, thereby protecting the thickness of the reinforcing steel cage's protective layer. Furthermore, during the construction of variable-diameter pile holes, there is no need to change drill bits back and forth, resulting in high construction efficiency.

[0021] 2. The method for constructing variable diameter pile holes suitable for deep, large-diameter pebble geology provided by this invention adopts a combination of inner and outer casings, which solves the problem of difficult segmented sinking of steel casings for variable diameter piles in deep, large-diameter pebble geology using special equipment.

[0022] Other advantages, objectives and features of the present invention will become apparent in part from the following description, and in part from those skilled in the art through study and practice of the invention. Attached Figure Description

[0023] Figure 1 This is a schematic diagram of the integrated drill bit structure when the large-diameter drill bit is used for drilling according to the present invention;

[0024] Figure 2 This is a schematic diagram of the integrated drill bit structure when the small-diameter drill bit is used for drilling according to the present invention;

[0025] Figure 3 for Figure 2 A magnified view of part A;

[0026] Figure 4 This is a top view of the sliding clamp described in this invention;

[0027] Figure 5 This is a schematic diagram of the structure of the driving device described in this invention; Detailed Implementation

[0028] The present invention will now be described in further detail with reference to the accompanying drawings, so that those skilled in the art can implement it based on the description.

[0029] It should be noted that, unless otherwise specified, the experimental methods described in the following embodiments are all conventional methods, and the reagents and materials described are all commercially available unless otherwise specified. In the description of this invention, the terms "lateral", "longitudinal", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", and "outer" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this invention.

[0030] This invention provides a method for constructing variable-diameter pile holes suitable for deep, large-diameter pebble geology. A rotary drilling rig 100 is used for the construction of the variable-diameter pile holes. The pile holes include a large-diameter pile hole and a small-diameter pile hole coaxially arranged from top to bottom. The method is characterized by an integrated drill bit installed at the bottom of the drill rod 110 of the rotary drilling rig. The integrated drill bit includes a large-diameter drill bit 300 for drilling the large-diameter pile hole and a small-diameter drill bit 400 for drilling the small-diameter pile hole. When drilling the large-diameter pile hole, the large-diameter drill bit 300 is sleeved on the outside of the small-diameter drill bit 400, and both are fixedly connected to the bottom of the drill rod 110. When drilling the small-diameter pile hole, the large-diameter drill bit 400 is fixed to the drill rod 110 by a sliding clamp 200 to guide the drill rod 110.

[0031] Specifically, the following steps are included:

[0032] S1. The integrated drill bit is installed at the bottom of the drill rod 110, wherein the top of the small diameter drill bit 400 is detachably connected to the bottom of the drill rod 110; the sliding clamp 200 is fixedly connected to the top of the large diameter drill bit 300, and the sliding clamp 200 is detachably connected to the bottom of the drill rod 110.

[0033] like Figure 1As shown, the rotary drilling rig is a conventionally used rotary drilling rig in the prior art. The bottom of the drill rod 110 is provided with a square head that connects to the drill bit. The small-diameter drill bit 400 can be detachably connected to the square head at the bottom of the drill rod 110 using a conventional pin shaft. That is, a square box that mates with the square head is provided on the top of the small-diameter drill bit 400, and pin holes are opened at corresponding positions on the square head and the square box, and then the two are connected by a pin shaft. The large-diameter drill bit 300 is connected to the drill rod 110 through the sliding clamp 200, which is fitted onto the outside of the small-diameter drill bit 400, and the sliding clamp 200 is connected to the square head. At this time, the same connection method as the small-diameter drill bit 400 can be used, using a pin shaft for connection. Corresponding pin holes are opened on the sliding clamp 200. When the gap between the sliding clamp 200 and the square head is large, in order to ensure the stability of the connection, a tightening block can be further provided between the square head and the sliding clamp 200.

[0034] S2. Drill to the designed position using the large-diameter drill bit 300 and install the outer casing; after the outer casing is installed, disconnect the sliding clamp 200 from the bottom of the drill rod 110.

[0035] S3. After the sliding clamp 200 and the large-diameter drill bit 300 are moved to the corresponding positions on the drill rod by the traction device, the sliding clamp 200 clamps the drill rod; at this time, the large-diameter drill bit 300 is in a non-working state, such as... Figure 2 As shown.

[0036] S4. Lower the drill rod 110 and drill through the small-diameter drill bit 400 to the bottom of the pebble layer, and install the inner casing; use the inner casing to prevent the pebble layer from collapsing.

[0037] S5. Drill downwards to the designed pile bottom using the small-diameter drill bit 400 to complete the pile foundation construction;

[0038] In step S3, the corresponding positions of the sliding clamp 200 and the large-diameter drill bit 300 on the drill rod 110 are as follows: during the downward drilling process of the small-diameter drill bit 400, the sliding clamp 200 and the large-diameter drill bit 400 are located above the diameter change point of the variable-diameter pile hole. That is, the sliding clamp 200 and the large-diameter drill bit 400 are always inside the large-diameter pile hole when the small-diameter drill bit 400 is drilling downward, providing guidance for the drill rod 110, ensuring that the large-diameter pile hole and the small-diameter pile hole are coaxially arranged, thereby ensuring the thickness of the reinforcing steel protective layer of the reinforcing cage.

[0039] In the above process, the outer casing and inner casing can be laid down using a rotary drilling rig with the integrated drill bit, or a crawler crane with a vibratory hammer.

[0040] Specifically, in steps S4 and S5, during the downward drilling process of the small-diameter drill bit 400, the position of the sliding clamp 200 and the large-diameter drill bit 400 on the drill rod is adjusted by the traction device, and the sliding clamp 200 is used to clamp or release the drill rod so that the sliding clamp 200 and the large-diameter drill bit 300 are always kept 30-40cm above the diameter change point of the variable-diameter pile hole.

[0041] Considering that the drill rod 110 needs to be lifted upwards multiple times during the construction of the variable diameter pile hole, the sliding clamp 200 is loosened during the upward lifting process. The position of the sliding clamp 200 and the large-diameter drill bit 400 is adjusted by the traction device to maintain a certain distance between them and the power head 120 of the rotary drilling rig, so as to avoid collision with the power head 120.

[0042] To facilitate adjustment of the sliding clamp 200 in clamping or releasing the drill rod 110, the sliding clamp 200 further includes a fixed clamp band 210 and a movable clamp band 250, which clamp the drill rod 110 after docking. The bottom surface of the fixed clamp band 210 is fixedly connected to the top surface of the large-diameter drill bit 300, and the movable clamp band 250 is slidably connected to the top surface of the large-diameter drill bit 300. The inner diameter of the annular space formed after the fixed clamp band 210 and the movable clamp band 250 dock is not greater than the diameter of the drill rod 110. That is, when the movable clamp band 250 slides to dock with the fixed clamp band 210, the sliding clamp clamps the drill rod 110; when the movable clamp band 250 slides in the opposite direction, the drill rod 110 is released. Preferably, referring to... Figure 3 Considering the stable connection between the movable clamp 250 and the large-diameter drill bit 300, so that when the traction device pulls the sliding clamp 200 to slide, the movable clamp 250 and the fixed clamp 310 together drive the large-diameter drill bit 300 to slide synchronously. The top surface of the large-diameter drill bit 300 is fixedly provided with two parallel inverted L-shaped slides 310, and the two sides of the movable clamp 250 are provided with horizontally extending sliders 243 corresponding to the slides 310.

[0043] like Figure 4 and Figure 5As shown, the sliding clamp 200 also includes a driving device 230. Both ends of the fixed clamp 210 and the movable clamp 250 are provided with connecting blocks 240 extending horizontally. The driving device 230 is provided on each connecting block 240 at both ends of the fixed clamp 210. The driving device 230 is used to drive the movable clamp to move closer to or away from the fixed clamp 210. To facilitate the installation of the driving device 230 and to achieve automatic adjustment of the movable clamp 250, connecting blocks 241 are provided at both ends of the fixed clamp 210, and connecting blocks 242 are provided at both ends of the movable clamp 250. When the connecting blocks at both ends of the fixed clamp 210 and the movable clamp 250 are connected, the fixed clamp 210 and the movable clamp 250 are also connected synchronously.

[0044] Reference Figure 5 The driving device 230 includes a drive motor 231, a lead screw 233, and a lead screw slider 232. The drive motor 231 is fixedly connected to the connecting block 241 of the fixed clamp 210, and its output end is fixedly connected to the lead screw 233. The lead screw slider 232 is fitted onto the lead screw 233 and is fixedly embedded within the connecting block 242 of the movable clamp 250. In actual use, the drive motor 231 can be a waterproof motor during drilling, and a long cable can be used for electrical connection. The drive motor 231 drives the lead screw 233 to rotate, thereby driving the lead screw slider 232 to move along the lead screw 233. The lead screw slider 232 is fixedly embedded within the connecting block 242 so that the lead screw slider 232 can drive the connecting block 242 to move, and the lead screw sliders 232 at both ends of the movable clamp 250 synchronously drive the movable clamp 250 to move. It should be noted that the driving device 230 can also be an electric telescopic rod or a hydraulic telescopic rod, with its fixed end connected to the fixed band 210 and its movable end connected to the movable band 250. Through its telescopic movement, the movable band can be driven to move closer to or away from the fixed band 210.

[0045] Reference Figure 4The sliding clamp 200 includes multiple compensation devices 220 spaced along its inner wall. Each compensation device 220 includes an elastic pressure plate and a compression spring. The two ends of the elastic pressure plate are fixedly connected to the inner wall of the sliding clamp 200; one end of the compression spring is fixedly connected to the inner wall of the sliding clamp 200, and the other end is fixedly connected to the middle of the elastic pressure plate. Considering the relative sliding between the drill rod 110 and the power head 120, the outer wall of the drill rod 110 has a groove. The compensation device 220 is provided to ensure the clamping force between the sliding clamp 200 and the drill rod 110. The elastic pressure plate can be a metal or rubber component with a certain elasticity. When its two ends are fixed, it can deform under the action of the drill rod 110 or the compression spring. When the sliding clamp 200 clamps the drill rod 110, the elastic pressure plate will press against the inner wall of the groove under the action of the compression spring. 9. The method for constructing variable diameter pile holes in deep, large-diameter pebble geology as described in claim 2, characterized in that the traction device is a winch, the winch is fixedly mounted on the rotary drilling rig, and the wire rope of the winch is fixedly connected to the top of the sliding clamp.

[0046] The traction device is a winch, which is fixedly mounted on the rotary drilling rig 100. The winch's wire rope is fixedly connected to the top of the sliding clamp 200. The winch retracts and extends the wire rope, causing the sliding clamp 200 to slide along the drill rod 110. The winch can be connected to the control module of the rotary drilling rig 100 for centralized control from the operator's cab, facilitating the determination of the position of the sliding clamp 200 relative to the large-diameter drill bit 300 and the distance between it and the power head 120.

[0047] Although embodiments of the present invention have been disclosed above, they are not limited to the applications listed in the specification and embodiments. They can be applied to various fields suitable for the present invention. For those skilled in the art, other modifications can be easily made. Therefore, without departing from the general concept defined by the claims and their equivalents, the present invention is not limited to the specific details and illustrations shown and described herein.

Claims

1. A method for variable-diameter pile hole construction suitable for deep and large-diameter pebble geology, wherein a rotary drilling rig is used to perform variable-diameter pile hole construction, the variable-diameter pile hole comprises a large-diameter pile hole and a small-diameter pile hole coaxially arranged from top to bottom, and the method is characterized in that, An integrated drill bit is installed at the bottom of the drill rod of the rotary drilling rig, the integrated drill bit comprising a large-diameter drill bit for drilling large-diameter pile holes and a small-diameter drill bit for drilling small-diameter pile holes; when drilling the large-diameter pile holes, the large-diameter drill bit is sleeved outside the small-diameter drill bit, and the two are fixedly connected with the bottom of the drill rod, respectively; when drilling the small-diameter pile holes, the large-diameter drill bit is fixed on the drill rod by a sliding clamp for guiding the drill rod; The method comprises the following steps: S1, installing the integrated drill bit at the bottom of the drill rod, wherein the top of the small-diameter drill bit is detachably connected with the bottom of the drill rod; the sliding clamp is fixedly connected with the top of the large-diameter drill bit, and the sliding clamp is detachably connected with the bottom of the drill rod; S2, drilling to the designed position by the large-diameter drill bit and burying an outer casing; after the outer casing is buried, the connection between the sliding clamp and the bottom of the drill rod is released; S3, driving the sliding clamp and the large-diameter drill bit to move upward to the corresponding position on the drill rod by a traction device, and then clamping the drill rod by the sliding clamp; S4, lowering the drill rod, drilling to the bottom of the gravel layer by the small-diameter drill bit, and burying an inner casing; S5, drilling downward to the designed pile bottom by the small-diameter drill bit to complete the pile foundation construction; In step S3, the corresponding position of the sliding clamp and the large-diameter drill bit on the drill rod is that, during the downward drilling of the small-diameter drill bit, the sliding clamp and the large-diameter drill bit are located above the variable-diameter position of the variable-diameter pile hole; The sliding clamp comprises a fixed clamp belt and a movable clamp belt, and the two are clamped after being abutted; the bottom surface of the fixed clamp belt is fixedly connected with the top surface of the large-diameter drill bit, and the movable clamp belt is slidably connected with the top surface of the large-diameter drill bit; the sliding clamp further comprises a driving device, and the two ends of the fixed clamp belt and the movable clamp belt are provided with a connecting block extending in the horizontal direction; the connecting block at the two ends of the fixed clamp belt is provided with the driving device, and the driving device is used to drive the movable clamp belt to move close to or away from the fixed clamp belt.

2. The method according to claim 1, wherein the method is applied to deep and large-diameter boulder geology. During the downward drilling of the small-diameter drill bit, the position of the sliding clamp and the large-diameter drill bit on the drill rod is adjusted by the traction device, and the drill rod is clamped or released by the sliding clamp, so that the sliding clamp and the large-diameter drill bit are always kept at a position 30-40 cm above the variable-diameter position of the variable-diameter pile hole.

3. The method according to claim 1, wherein the method is applied to deep and large-diameter boulder geology. During the upward lifting of the drill rod, the sliding clamp is loosened, and the position of the sliding clamp and the large-diameter drill bit is adjusted by the traction device, so that the two are kept at a certain distance from the power head of the rotary drilling rig.

4. The method according to claim 1, wherein the method is applied to deep and large-diameter boulder geology. The driving device comprises a driving motor, a lead screw, and a lead screw sliding block; the driving motor is fixedly connected with the connecting block of the fixed clamp belt, and the output end thereof is fixedly connected with the lead screw; the lead screw sliding block is sleeved on the lead screw and is fixedly embedded in the connecting block of the movable clamp belt.

5. The method for constructing variable-diameter pile holes suitable for deep, large-diameter pebble geology as described in claim 1, characterized in that, The sliding hoop comprises a plurality of compensation devices arranged at intervals along the inner wall of the sliding hoop, the compensation device comprising an elastic pressing piece and a compression spring, both ends of the elastic pressing piece being fixedly connected with the inner wall of the sliding hoop; one end of the compression spring is fixedly connected with the inside of the sliding hoop, and the other end is fixedly connected with the middle part of the elastic pressing piece.

6. The method for constructing variable-diameter pile holes suitable for deep, large-diameter pebble geology as described in claim 1, characterized in that, The traction device is a winch, the winch is fixedly arranged on the rotary drilling rig, and the steel wire rope of the winch is fixedly connected with the top of the sliding hoop.

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