A rotary drilling rig with an enlarged diameter drill bit and its steel casing for full-process pile construction

Abstract

The rotary drilling and expanding drill bit of the present invention comprises an upper structure and a lower structure. The upper portion of the upper structure is a connecting portion. The central shaft sleeve below the upper structure is sleeved with the central shaft sleeve of the lower structure. A compression spring is provided in the hollow portion of the sleeve. The side portion of the upper structure is hinged to the end of the upper connecting rod, and the other end of the upper connecting rod is hinged to the tooth seat. The side portion of the lower structure is hinged to the end of the lower connecting rod, and the other end of the lower connecting rod is hinged to the tooth seat. A plurality of drill teeth are arranged on the outer side of the tooth seat. The present invention can achieve that the drill bit reaches the bottom of the pile hole, and the side hole expansion mechanism opens to rotary excavate the side wall of the pile hole, and the pile hole is expanded into a cylindrical shape. Therefore, when constructing pile holes in complex foundations that are prone to collapse, using this rotary drilling and expanding drill bit can achieve that the steel casing follows the rotary drilling bit throughout the entire process of entering the deep pile hole, thereby preventing the pile hole from collapsing.

Description

Technical Field

[0001] The invention relates to the technical field of pile foundation construction, in particular to a construction application of a rotary drilling rig with an enlarged diameter drill bit and a steel casing thereof for full-process follow-up pile formation. Background Art

[0002] Rotary drilling is a construction process suitable for drilling holes in building foundation projects. It is widely used in municipal construction, highway bridges, high-rise buildings, and other foundation construction projects. Combined with different drilling tools, it is suitable for drilling holes in various foundation types. A steel casing or steel cage is placed in the drilled pile hole and concrete is poured to complete the pile foundation construction. Rotary drilling uses a drilling rig to drill the hole. The barrel-shaped drill bit with a valve at the bottom of the drilling rig rotates to crush the rock and soil, and directly loads it into the drill bucket. The drill rig's lifting device and telescopic drill rod then lift the drill bucket out of the hole to remove soil and debris. This cycle is repeated, continuously removing and unloading soil until the designed depth is reached.

[0003] Expansion drilling involves drilling to the designed depth using a standard barrel drill bit. The drill is then replaced with a dedicated expansion drill bit and re-entered into the pile hole. Once the expansion drill bit contacts the bottom of the pile hole, downward pressure is applied to the bit, causing the expansion mechanism on the side of the drill bit to expand from a contracted state. The drill teeth on the mechanism then rotate and dig into the side of the pile hole, expanding the end of the pile hole to a larger diameter than the original drilled hole. Once the downward pressure is released, the expansion drill bit returns to its contracted state and is withdrawn from the pile hole, completing the drilling and expansion process. The expanded pile foundation is more stable and has a stronger single-pile bearing capacity.

[0004] In the existing enlarging rotary drilling bit, the side enlarging mechanism mainly achieves diameter expansion through components such as a spring, a central shaft, a side enlarging mechanism and drill teeth. When the rotary drilling bit sinks and overcomes the spring force to apply downward pressure, the enlarging mechanism expands to form a triangular shape. Then the rotary drilling bit rotates, and the drill teeth rotary dig the side wall of the pile hole, eventually forming a conical enlarged hole shape.

[0005] During bored pile construction, due to the instability of the soil and the difficulty of constructing reinforced concrete retaining walls, wooden, steel, or concrete cylindrical retaining walls are used to protect the piles and prevent collapse, thereby impacting construction progress and safety. Casing is particularly important in areas with challenging geological conditions, such as those with limestone and karst lava formations. Steel casing is also commonly used in rotary pile boring. Typically, the diameter of the rotary drill bit is larger than the outer diameter of the steel casing. After drilling to the desired height, the drill bit is withdrawn, the slag is cleared, and the steel casing is lowered into the pile hole. However, in areas prone to landslides and collapse, the pile hole can collapse after the drill bit is withdrawn. Before the steel casing can be lowered, collapsed rock and soil can re-block the pile hole, causing construction delays and failures. Summary of the Invention

[0006] The present invention provides a rotary drilling diameter expansion drill bit and its steel casing for full-time pile construction application. The new rotary drilling diameter expansion drill bit can achieve the drill bit reaching the bottom of the pile hole, and the side hole expansion mechanism is opened to rotary drill the side wall of the pile hole, and the pile hole is expanded into a cylindrical shape. Therefore, when constructing pile holes in complex foundations that are prone to collapse, using this rotary drilling diameter expansion drill bit can achieve the steel casing following the rotary drilling bit into the depth of the pile hole throughout the process, thereby preventing the pile hole from collapsing.

[0007] In order to achieve the above-mentioned purpose of the present invention, the technical solution adopted is:

[0008] A rotary drilling enlarging drill bit comprises an upper structure and a lower structure, wherein the upper portion of the upper structure is a connecting portion, and the central shaft sleeve below the upper structure is sleeved with the central shaft sleeve of the lower structure; a compression spring is provided in the hollow portion of the sleeve, the side portion of the upper structure is hinged to the end portion of the upper connecting rod, and the other end of the upper connecting rod is hinged to the tooth seat beam; the side portion of the lower structure is hinged to the end portion of the lower connecting rod, and the other end of the lower connecting rod is hinged to the tooth seat beam; a plurality of tooth seats are arranged on the outer side of the tooth seat beam, and the drill teeth are fixed on the tooth seats.

[0009] The uppermost connecting part is connected to the drill arm of the drilling machine, and the upper and lower central axis sleeves of the drill bit are sleeved and slide freely, so that the upper and lower parts of the drill bit can be compressed or elongated; the compression spring arranged in the hollow of the sleeve keeps the upper and lower parts of the drill bit in an elongated state without being subjected to external pressure; a parallelogram-like structure is formed between the upper connecting rod, the lower connecting rod and the tooth seat, and the parallel sides of the parallelogram structure can change shape to make the tooth seat extend or shrink.

[0010] The outer circumference of the upper structure is provided with fan-shaped ribs, and the multi-layer fan-shaped ribs can increase the overall annular rigidity of the drill bit and prevent it from being deformed under strong torsional forces.

[0011] The diameter expansion mechanism composed of the upper connecting rod, the lower connecting rod, the tooth seat beam, the tooth seat and the drill teeth is evenly distributed on the circumference. The number of the diameter expansion mechanism can be more than 2. When the diameter of the drill bit increases, the designed diameter expansion mechanism can be increased accordingly.

[0012] The upper connecting rods are divided into two groups, and the lower connecting rods are divided into one group. The multiple groups of connecting rod structures can increase the stability and rigidity of the diameter expansion mechanism, so that the diameter expansion mechanism has a stronger supporting force and is not easy to deform.

[0013] The enlarged diameter drill bit of rotary drilling can be used in various pile hole rotary drilling construction sites.

[0014] The rotary drilling drill with an enlarged diameter drill bit, during the rotary drilling of pile holes, the steel casing follows the pile formation process throughout the entire process, including:

[0015] (1) Use a common drill bit with a diameter larger than the outer diameter of the steel casing to drill into the ground to the junction of the soil layer and the rock layer;

[0016] (2) Pull out the rotary drill, replace the slag cleaning cylinder and enter the pile hole to clean the slag;

[0017] (3) After the slag is cleared, insert the first section of the steel casing into the pile hole;

[0018] (4) Replace the drill bit with a smaller diameter than the inner diameter of the steel casing, enter the pile hole from the inner diameter of the steel casing and continue to drill downward for 1.5m;

[0019] (5) Pull out the rotary drill, replace the slag cleaning cylinder and enter the pile hole to clean the slag;

[0020] (6) Replace the rotary drilling and reaming drill bit, and enter the bottom of the pile hole from the inner diameter of the steel casing to expand the diameter until the pile hole diameter is 20-80mm larger than the outer diameter of the steel casing;

[0021] (7) Pull out the reamer, replace the slag removal tube and enter the bottom of the pile hole to remove the slag;

[0022] (8) After the slag is cleared, the steel casing is lowered to the bottom of the pile hole. If the steel casing is about to sink below the ground level, a new section of steel casing is welded and continued to sink;

[0023] (9) Repeat steps (4) to (8) until the steel casing reaches the predetermined depth, insert the steel cage, and pour concrete, thus completing the construction of the steel casing and pile formation.

[0024] The substantial features and advancements of the present invention over the prior art are:

[0025] 1. The present invention changes the conical expansion shape of the traditional expansion rotary drill bit. The parallelogram structure of the expansion mechanism can form a cylindrical expansion shape, which has a stable structure and is easy to maintain.

[0026] 2. The expanded diameter rotary drill bit of the present invention allows the steel casing to follow the rotary drill bit throughout the entire process of entering the pile hole, even in complex and prone-to-collapse pile hole construction. The steel casing can protect the pile hole throughout any stage of the downward pile hole construction, which is particularly significant in areas of the southwest where karst landforms are prevalent. In previous construction stages, if the pile hole construction process encountered underground rivers or underground caves, the fragile porous landform would be vibrated, and the groundwater flow would impact the broken limestone, causing the pile hole sidewalls to collapse. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 This is a schematic diagram of the cross-section of the enlarged diameter rotary drilling drill bit of the present invention (the enlarged diameter mechanism is in a retracted, non-working state);

[0028] Figure 2This is a schematic diagram of the cross-section structure of the enlarged rotary drilling drill bit of the present invention (the enlargement mechanism is in the open working state);

[0029] Figure 3 This is a schematic diagram of the appearance and structure of the enlarged diameter rotary drilling drill bit of the present invention (the enlarged diameter mechanism is in a retracted non-working state);

[0030] Figure 4 This is a structural diagram of the steel casing following the pile construction throughout the entire process in the present invention;

[0031] The marked serial numbers in the figure are: 1. Connection part; 2. Upper structure; 3. Lower structure; 4. Compression spring; 5. Upper connecting rod; 6. Lower connecting rod; 7. Tooth seat beam; 8. Drill teeth; 9. Fan-shaped ribs; 10. Steel casing. DETAILED DESCRIPTION

[0032] Example 1

[0033] A rotary drilling enlarging drill bit includes an upper structure 2 and a lower structure 3. The upper part of the upper structure 2 is a connecting part 1, and the central shaft sleeve below the upper structure 2 is sleeved with the central shaft sleeve of the lower structure; a compression spring 4 is provided in the hollow part of the sleeve, the side of the upper structure 2 is hinged to the end of the upper connecting rod 5, and the other end of the upper connecting rod 5 is hinged to the tooth seat beam 7; the side of the lower structure 3 is hinged to the end of the lower connecting rod 6, and the other end of the lower connecting rod 6 is hinged to the tooth seat beam 7; a plurality of tooth seats are arranged on the outer side of the tooth seat beam 7, and drill teeth 8 are fixed on the tooth seats.

[0034] Sector-shaped ribs 9 are provided on the outer circumference of the upper structure 2 .

[0035] The diameter expansion mechanisms composed of the upper connecting rod 5, the lower structure 3, the tooth seat beam 7, the tooth seat and the drill teeth 8 are evenly distributed on the circumference, and the number of the diameter expansion mechanisms is four.

[0036] The upper connecting rods 5 are divided into two groups, and the lower connecting rods 6 are divided into one group.

[0037] The rotary drilling drill with an enlarged diameter drill bit, during the rotary drilling of pile holes, the steel casing follows the pile formation process throughout the entire process, including:

[0038] (1) Use a common drill bit with a larger diameter than the outer diameter of the steel casing to drill into the ground to the depth of the junction of the soil layer and the rock layer; (2) Pull out the drill bit, replace the slag removal barrel and enter the pile hole to remove the slag;

[0039] (3) After the slag is cleared, insert the first section of the steel casing into the pile hole;

[0040] (4) Replace the drill bit with a smaller diameter than the inner diameter of the steel casing, enter the pile hole from the inner diameter of the steel casing and continue to drill downward for 1.5m;

[0041] (5) Pull out the rotary drill, replace the slag cleaning cylinder and enter the pile hole to clean the slag;

[0042] (6) Replace the rotary drilling and reaming drill bit and enter the bottom of the pile hole from the inner diameter of the steel casing to expand the diameter until the pile hole diameter is 50 mm larger than the outer diameter of the steel casing;

[0043] (7) Pull out the reamer, replace the slag removal tube and enter the bottom of the pile hole to remove the slag;

[0044] (8) After the slag is cleared, the steel casing is lowered to the bottom of the pile hole. If the steel casing is about to sink below the ground level, a new section of steel casing is welded and continued to sink;

[0045] (9) Repeat steps (4) to (8) until the steel casing reaches the predetermined depth, insert the steel cage, and pour concrete, thus completing the construction of the steel casing and pile formation.

[0046] Example 2

[0047] The rotary drilling rig diameter expansion drill bit can be used for expanding the bottom of a pile foundation to expand a cylindrical pile root. The cylindrical pile root has a stronger bearing capacity than a conical pile root and can meet special design requirements.

Claims

1. Application of a rotary drilling drill with an enlarged diameter in pile hole rotary drilling construction, characterized by: The rotary drilling rig enlarging drill bit comprises an upper structure (2) and a lower structure (3), wherein the upper portion of the upper structure (2) is a connecting portion (1), and the middle shaft sleeve below the upper structure (2) is sleeved with the middle shaft sleeve of the lower structure; a compression spring (4) is provided in the hollow portion of the sleeve; the side portion of the upper structure (2) is hinged to the end of the upper connecting rod (5), and the other end of the upper connecting rod (5) is hinged to the tooth seat beam (7); the side portion of the lower structure (3) is hinged to the end of the lower connecting rod (6), and the other end of the lower connecting rod (6) is hinged to the tooth seat beam (7); a plurality of tooth seats are arranged on the outer side of the tooth seat beam (7), and drill teeth (8) are fixed on the tooth seats; The steps of using the rotary drilling drill with an expanded diameter drill bit to form piles during rotary drilling of pile holes and the steel casing to follow up the piles throughout the process include: (1) Use a common drill bit with a diameter larger than the outer diameter of the steel casing to drill into the ground to the junction of the soil layer and the rock layer; (2) Pull out the rotary drill, replace the slag cleaning cylinder and enter the pile hole to clean the slag; (3) After the slag is cleared, insert the first section of the steel casing into the pile hole; (4) Replace the drill bit with a smaller diameter than the inner diameter of the steel casing, enter the pile hole from the inner diameter of the steel casing and continue to drill downward for 1.5m; (5) Pull out the rotary drill, replace the slag cleaning cylinder and enter the pile hole to clean the slag; (6) Replace the rotary drilling rig expansion drill bit and enter the bottom of the pile hole from the inner diameter of the steel casing to expand the diameter until the pile hole diameter is 20-80mm larger than the outer diameter of the steel casing; (7) Pull out the reamer, replace the slag removal tube and enter the bottom of the pile hole to remove the slag; (8) After the slag is cleared, the steel casing is lowered to the bottom of the pile hole. If the steel casing is about to sink below the ground level, a new section of steel casing is welded and continued to sink; (9) Repeat steps (4) to (8) until the steel casing reaches the predetermined depth, insert the steel cage, and pour concrete, thus completing the construction of the steel casing and pile formation.

2. The application of the rotary drilling enlarged diameter drill bit according to claim 1 in pile hole rotary drilling construction is characterized in that: Sector-shaped ribs (9) are provided on the outer circumference of the upper structure (2).

3. The application of the rotary drilling enlarged diameter drill bit according to claim 1 in pile hole rotary drilling construction is characterized in that: The diameter expansion mechanism composed of the upper connecting rod (5), the lower connecting rod (6), the tooth seat beam (7), the tooth seat and the drill teeth (8) is distributed on the circumference, and the number of the diameter expansion mechanisms is more than two.

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