Cast-in-place concrete pile forming construction method and cast-in-place concrete pile casing

Abstract

The invention provides a cast-in-place concrete pile forming construction method and a cast-in-place concrete pile casing. The cast-in-place concrete pile forming construction method comprises the following steps that a pipe barrel and ribs are made into the casing; a positioning screw is screwed into a positioning hole in the surface of the pile casing; the two pile casings are in quick butt joint through the positioning clamping grooves and the positioning screws, the pile casings are pushed into the soil body one by one through the rotary drilling rig, the soil body in the pile casings is removed, and pile holes are obtained; a reinforcement cage is placed in the pile hole, and concrete is poured; pulling out the pile casings one by one from the soil body by using a rotary drilling rig; by the adoption of the technical scheme, when the rotary drilling rig is used for pushing the pile casing or pulling the pile casing out, the rotary drilling rig enables the pile casing to rotate around the axis of the pile casing, the ribs cut the soil body at the same time, the cohesive force of the soil body is destroyed, resistance generated when the pile casing is pushed in or pulled out is reduced, and construction efficiency is improved.

Description

Technical Field

[0001] The invention belongs to the technical field of construction engineering, and in particular relates to a concrete bored pile construction method and a concrete bored pile casing. Background Art

[0002] During the construction of concrete bored piles, in order to prevent the collapse of the soil on the inner wall of the pile hole, corresponding steel casings are usually driven into the ground soil first. For backfill areas and areas with poor geological conditions, casings are required to follow up. Since the length of each section of casing is limited and some buildings require very deep pile foundations, the casings are often spliced together two by two, driven into the ground soil one by one, and then the soil inside the casings is removed.

[0003] In the prior art, a patent document with the authorization announcement number "CN110130337B" discloses a pile driving method that can reduce the resistance to pile driving, which includes the following steps: S1. Determine the soil layer conditions and their physical and mechanical parameters based on the survey report, and determine the designed pile diameter D of the precast pile according to the engineering design requirements; S2. Establish a solid model that conforms to the actual stratum conditions through numerical simulation software, and assign it corresponding physical and mechanical parameters; S3. Open a hole with an aperture d in the solid model, and place a precast pile at the hole mouth, calculate the energy consumption of pile driving under different hole diameters, and fit the relationship curve between the energy consumption of pile driving and the aperture d based on the calculation results, find the intersection of the relationship curve and the energy consumption curve of digging a hole, and use the value of the aperture d at the intersection as the optimal aperture dop; S4. Drill a hole at the pile driving position, inject cement slurry, put the precast pile in place, align the pile axis with the hole axis, and drive the pile. The use of this patented technology, combined with the cast-in-place pile construction process and the prefabricated pile construction process, has improved construction efficiency to a certain extent. However, if the pile hole depth increases, the number of casings that need to be spliced will increase significantly, which means that the pressure required to press the casing into the soil will be greater, and the corresponding power demand of the piling equipment will also be higher. The power of the piling equipment cannot be expanded indefinitely, resulting in increasing resistance to the casing entering the soil. Summary of the Invention

[0004] In order to solve the above technical problems, the present invention provides a concrete bored pile construction method and a concrete bored pile casing.

[0005] The present invention is achieved through the following technical solutions.

[0006] The present invention provides a concrete cast-in-place pile construction method, comprising the following steps:

[0007] Step 1: Provide the tube;

[0008] Step 2: providing ribs, and fixing the ribs to the inner wall of the tube along a spiral trajectory;

[0009] Step 3: First, a plurality of positioning holes are drilled on one end of the tube, and then a plurality of positioning slots are cut on the edge of the other end of the tube;

[0010] Step 4: Repeat steps 1 to 3 several times to make several casings from the tubes and ribs;

[0011] Step 5: providing a rotary drilling rig having an output shaft;

[0012] Step 6: Take one of the casings and securely connect it to the output shaft of the rotary drilling rig;

[0013] Step 7: Using the power provided by the rotary drilling rig, the casing is pushed into the soil in the vertical direction. When the height of the portion of the casing exposed above the ground is less than a preset height threshold, the pushing of the casing is stopped.

[0014] Step 8: Separate the casing from the output shaft and remove the soil inside the casing;

[0015] Step 9: Take another casing and connect it to the previous casing using the fastening assembly;

[0016] Step 10: Repeat steps 6 to 9 several times to form a pile hole on the ground;

[0017] Step 11: placing a steel cage into the pile hole and pouring concrete;

[0018] Step 12: Connect the partially exposed casing to the output shaft of the rotary drilling rig, and then use the power provided by the rotary drilling rig to completely pull the casing out of the soil in the vertical direction and stop, and then separate the casing from other casings and the rotary drilling rig;

[0019] Step 13: Repeat step 12 several times until all casings are completely pulled out of the soil, and the construction is completed.

[0020] The order of implementing steps 2 and 3 can be interchanged.

[0021] In step seven, the height threshold does not exceed 1m.

[0022] In step nine, the fastening assembly includes a positioning nut and a positioning screw. Using the fastening assembly to connect it to the previous casing means threading the positioning nut and the positioning screw, and passing the positioning screw through the positioning hole and the positioning slot.

[0023] The positioning hole is a countersunk through hole with a step, the positioning nut is a countersunk nut with a step, and the positioning screw is a countersunk screw.

[0024] The surface of the casing is also machined with a number of anti-rotation grooves, each of which is connected to at least one of the positioning holes. Positioning bosses are also provided around the positioning nut. When the fastening assembly is used to connect it to the previous casing, the positioning bosses are fitted into the corresponding anti-rotation grooves.

[0025] In addition, the present invention also provides a concrete cast-in-place pile casing, comprising a tube and ribs, wherein the ribs are fixedly connected to the inner wall surface of the tube along a spiral trajectory.

[0026] The cross section of the rib is a semicircle with a radius of not less than 15 mm, and the pitch of the spiral trajectory does not exceed 200 mm.

[0027] The ribs may be replaced by steel bars.

[0028] The beneficial effect of the present invention is that: when the technical solution of the present invention is adopted, when the rotary drilling rig applies force to the casing to propel it into the soil, the axial component of the output force of the rotary drilling rig propels the casing downward in the vertical direction, while the radial component of the output force of the rotary drilling rig drives the casing to rotate around its own central axis. Since the ribs are fixed to the inner wall of the casing, the ribs have a cutting effect on the soil, breaking the soil and destroying the cohesion of the soil, thereby reducing the resistance of the soil to the casing, making it easier to push the casing into the soil. Conversely, when the casing is pulled out, the casing can also be more easily pulled out of the soil, thereby improving construction efficiency. In addition, positioning holes and positioning slots are provided on the surface of the casing. When the two casings are docked, it is only necessary to screw the positioning screws and the positioning nuts, thereby realizing rapid positioning and rapid splicing of the two casings, further improving construction efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1 It is a construction process flow chart of the present invention;

[0030] Figure 2 It is a front view of the casing of the present invention;

[0031] Figure 3 It is a schematic diagram of the connection of two casings of the present invention;

[0032] Figure 4 It is a partial enlarged view of the positioning hole of the present invention;

[0033] Figure 5 It is a front view of the positioning nut of the present invention.

[0034] In the figure: 1-tube, 2-positioning hole, 3-positioning slot, 4-positioning nut, 5-positioning screw, 6-anti-rotation groove, 7-positioning boss. DETAILED DESCRIPTION

[0035] The technical solution of the present invention is further described below, but the scope of protection claimed is not limited to the description.

[0036] like Figures 1 to 5 As shown, the present invention provides a concrete cast-in-place pile construction method, comprising the following steps:

[0037] Step 1: Provide a tube 1;

[0038] Step 2: providing ribs and fixing the ribs to the inner wall of the tube 1 along a spiral trajectory;

[0039] Step 3: First, drill a plurality of positioning holes 2 at one end of the tube 1, and then cut a plurality of positioning slots 3 at the edge of the other end of the tube 1;

[0040] Step 4: Repeat steps 1 to 3 several times to make several casings from the tube 1 and the ribs;

[0041] Step 5: providing a rotary drilling rig having an output shaft;

[0042] Step 6: Take one of the casings and connect it to the output shaft of the rotary drilling rig;

[0043] Step 7: Using the power provided by the rotary drilling rig, the casing is pushed into the soil in the vertical direction. When the height of the part of the casing exposed on the ground is less than a preset height threshold, the casing is stopped from being pushed forward.

[0044] Step 8: Separate the casing from the output shaft and remove the soil inside the casing;

[0045] Step 9: Take another casing and connect it to the previous casing using the fastening assembly;

[0046] Step 10: Repeat steps 6 to 9 several times to form a pile hole on the ground;

[0047] Step 11: Place the steel cage into the pile hole and pour concrete;

[0048] Step 12: Connect the partially exposed casing to the output shaft of the rotary drilling rig, and then use the power provided by the rotary drilling rig to completely pull the casing out of the soil in the vertical direction and stop, and then separate the casing from other casings and the rotary drilling rig;

[0049] Step 13: Repeat step 12 several times until all casings are completely pulled out of the soil, and the construction is completed.

[0050] According to the technical solution of the present invention, when the rotary drilling rig applies force to the casing to propel it into the soil, the axial component of the output force of the rotary drilling rig propels the casing downward in the vertical direction, while the radial component of the output force of the rotary drilling rig drives the casing to rotate around its own central axis. Since the ribs are fixedly connected to the inner wall of the casing, the ribs have a cutting effect on the soil, breaking up the soil and destroying the cohesion of the soil, thereby reducing the resistance of the soil to the casing, making it easier to push the casing into the soil. Conversely, when the casing is pulled out, it is also easier to pull the casing out of the soil, thereby improving construction efficiency. In addition, the surface of the casing is provided with positioning holes and positioning slots. When the two casings are docked, it is only necessary to screw the positioning screws and the positioning nuts together, thereby realizing rapid positioning and rapid splicing of the two casings, and further improving construction efficiency. Compared with the existing technology, in the process of pushing the casing into the soil, the positioning nuts and the positioning screws are separated from the casing, thereby preventing soil from covering the threaded surfaces of the positioning nuts and the positioning screws, and facilitating the cleaning of the soil filled in the positioning holes of the casing. The casing, the positioning nuts and the positioning screws can all be reused, effectively reducing the maintenance costs of the casing, the positioning nuts and the positioning screws.

[0051] Specifically, the order of implementing steps 2 and 3 can be interchanged. In step 4, the length of the casing does not exceed 3 meters. In step 7, the height threshold does not exceed 1 meter.

[0052] In addition, in step nine, the fastening assembly includes a positioning nut 4 and a positioning screw 5. Using the fastening assembly to connect it to the previous casing means threading the positioning nut 4 to the positioning screw 5, and making the positioning screw 5 pass through the positioning hole 2 and the positioning slot 3. Preferably, the positioning hole 2 is a countersunk through hole with a step, the positioning nut 4 is a countersunk nut with a step, and the positioning screw 5 is a countersunk screw. The nominal diameter of the positioning screw 5 is not less than φ20mm. The surface of the casing is also machined with a number of anti-rotation grooves 6, each of which is connected to at least one positioning hole 2. Positioning bosses 7 are also provided around the positioning nut 4. When the fastening assembly is used to connect it to the previous casing, the positioning bosses 7 are fitted into the corresponding anti-rotation grooves 6. By adopting the technical solution of the present invention, when the casing is pushed into the soil, since the positioning screw and the positioning nut are separated from the casing, the surface threads of the positioning screw and the positioning nut are prevented from being covered by the soil, affecting their threaded connection. When the positioning screw and the positioning nut are threaded together, the operator applies torque to the positioning screw. Since the positioning boss is fitted into the anti-rotation groove, the positioning nut can be prevented from rotating or slipping around its own axis. Moreover, the positioning nut is a countersunk nut with a step, and the positioning nut can be clamped between two adjacent casings to prevent the positioning nut from falling into the pile hole, so that the positioning screw and the positioning nut are connected and tightened.

[0053] In addition, the present invention provides a concrete cast-in-place pile casing, which includes a tube 1 and ribs, wherein the ribs are fixed to the inner wall surface of the tube 1 along a spiral trajectory.

[0054] Specifically, the cross-section of the rib is a semicircle with a radius of no less than 15 mm, and the pitch of the helical trajectory does not exceed 200 mm. The ribs can be replaced by steel bars. One end of the tube 1 is provided with a plurality of positioning holes 2, and the other end of the tube 1 is provided with a plurality of positioning slots 3. The number of positioning holes 2 and positioning slots 3 is at least four, and all positioning holes 2 and all positioning slots 3 are distributed in a circular array around the central axis of the tube 1.

Claims

1. A method for constructing a concrete bored pile, characterized by: The following steps are involved: Step 1: providing a tube (1); Step 2: providing ribs, and fixing the ribs to the inner wall surface of the tube (1) along a spiral trajectory; Step 3: First, a plurality of positioning holes (2) are drilled at one end of the tube (1), and then a plurality of positioning slots (3) are cut at the edge of the other end of the tube (1); Step 4: Repeat steps 1 to 3 several times to make several protective tubes from the tube (1) and ribs; Step 5: providing a rotary drilling rig having an output shaft; Step 6: Take one of the casings and securely connect it to the output shaft of the rotary drilling rig; Step 7: Using the power provided by the rotary drilling rig, the casing is pushed into the soil in the vertical direction. When the height of the portion of the casing exposed above the ground is less than a preset height threshold, the pushing of the casing is stopped. Step 8: Separate the casing from the output shaft and remove the soil inside the casing; Step 9: Take another casing and connect it to the previous casing using the fastening assembly; Step 10: Repeat steps 6 to 9 several times to form a pile hole on the ground; Step 11: placing a steel cage into the pile hole and pouring concrete; Step 12: Connect the partially exposed casing to the output shaft of the rotary drilling rig, and then use the power provided by the rotary drilling rig to completely pull the casing out of the soil in the vertical direction and stop, and then separate the casing from other casings and the rotary drilling rig; Step 13: Repeat step 12 several times until all casings are completely pulled out of the soil, and the construction is completed.

2. A method for constructing a cast-in-place concrete pile according to claim 1, characterized in that: The order of implementing steps 2 and 3 can be interchanged.

3. A method for constructing a cast-in-place concrete pile according to claim 1, characterized in that: In step seven, the height threshold does not exceed 1m.

4. A method for constructing a cast-in-place concrete pile according to claim 1, characterized in that: In step nine, the fastening assembly includes a positioning nut (4) and a positioning screw (5). Using the fastening assembly to connect it to the previous casing means screwing the positioning nut (4) and the positioning screw (5) together, and making the positioning screw (5) pass through the positioning hole (2) and the positioning slot (3).

5. A method for constructing a cast-in-place concrete pile according to claim 4, characterized in that: The positioning hole (2) is a countersunk through hole with a step, the positioning nut (4) is a countersunk nut with a step, and the positioning screw (5) is a countersunk screw.

6. A method for constructing a cast-in-place concrete pile according to claim 4, characterized in that: The surface of the casing is also machined to have a plurality of anti-rotation grooves (6), each of which is connected to at least one of the positioning holes (2). The positioning nut (4) is also provided with positioning bosses (7) around it. When the fastening assembly is used to connect it to the previous casing, the positioning bosses (7) are fitted into the corresponding anti-rotation grooves (6).

7. A concrete cast-in-place pile casing, characterized by: It comprises a tube (1) and ribs, wherein the ribs are fixedly connected to the inner wall surface of the tube (1) along a spiral trajectory.

8. A concrete cast-in-place pile casing according to claim 7, characterized in that: The cross section of the rib is a semicircle with a radius of not less than 15 mm, and the pitch of the spiral trajectory does not exceed 200 mm.

9. A concrete cast-in-place pile casing according to claim 7 or 8, characterized in that: The ribs may be replaced by steel bars.

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