A jet grouting drill bit and a composite pile formed by rotary digging using the drill bit

Abstract

This utility model belongs to the field of underground working well construction technology, specifically relating to a shotcrete drill bit and a composite pile formed by rotary drilling using this drill bit. The shotcrete drill bit includes a drill rod, a spiral blade disposed at the bottom of the drill rod, shotcrete blades disposed on the drill rod body, and a shotcrete head disposed on the shotcrete blades. The shotcrete blades are curved structures that bend backward in the middle. The shotcrete head is disposed at the leading edge of the bend of the shotcrete blades. The shotcrete blades are provided with a shotcrete channel connecting the shotcrete head and the internal channel of the drill rod. The shotcrete drill bit of this utility model can form a hollow cement mixing pile by rotary drilling and simultaneously shotcreting grout into the outer part of the formed hole using the shotcrete head. This not only simplifies the construction process but also reduces the amount of cement used.

Description

Technical Field

[0001] This utility model belongs to the field of composite pile construction technology, specifically relating to a shotcrete drill bit and a composite pile formed by rotary drilling using the drill bit. Background Technology

[0002] like Figure 1 As shown, the commonly used foundation pit support system consists of a row of bored piles and a row of high-pressure jet grouting water-stop curtains. The bored piles provide support on the inner side, using reinforced concrete, with a pile diameter of 800mm and a spacing of 1000mm. The high-pressure jet grouting water-stop curtains provide water-stopping on the outer side, using cement mortar, with a pile diameter of 600mm and a spacing of 400mm.

[0003] The disadvantages of this type of foundation pit support will gradually become apparent over time, mainly in the following aspects:

[0004] 1. Foundation pit leakage: There is a gap between the high-pressure jet grouting water-stop curtain outside the original plan and the inner cast-in-place piles, while the outer cement mixing piles are in direct contact with the soil. Based on past engineering experience, high-pressure jet grouting piles are prone to weakening at the interlocking parts due to soil pressure, resulting in cracking and leakage.

[0005] 2. Large site area occupied: The original plan used two rows of piles with a width of about 1680mm, while the current plan uses one row with a width reduced to 1400mm.

[0006] Therefore, composite piles have been adopted to replace this type of support. The outer layer consists of cement-mixed soil piles, while the inner core is a reinforced concrete cast-in-place pile. Composite piles utilize the shear bearing capacity of the cast-in-place piles to resist earth pressure, while the interlocking of the cement-mixed soil piles prevents leakage. Currently, the method for constructing these composite piles is as follows: cement-mixed soil piles are drilled in advance using a shotcrete drill bit, and then reinforced concrete cast-in-place piles are drilled into the cement-mixed soil piles. It is evident that the disadvantage of this construction process is the waste of cement materials.

[0007] Therefore, it is necessary to develop a new type of drill bit that can simplify the construction process and save construction materials. Utility Model Content

[0008] The purpose of this utility model is to provide a shotcrete drill bit and a composite pile formed by rotary drilling using the drill bit, which can simplify the construction process and save construction materials.

[0009] To achieve the above objectives, this utility model provides the following technical solution: a shotcrete drill bit, comprising a drill rod, a spiral blade disposed at the bottom of the drill rod, a shotcrete blade disposed on the drill rod body, and a shotcrete head disposed on the shotcrete blade. The shotcrete blade is a curved structure that curves backward in the middle. The shotcrete head is disposed at the leading edge of the curved part of the shotcrete blade. The shotcrete blade is provided with a shotcrete channel connecting the shotcrete head and the internal channel of the drill rod.

[0010] Furthermore, the shotcrete blade includes an integrally connected horizontal section and a turning section, the angle between the horizontal section and the turning section is an obtuse angle, and the shotcrete channel is located in the horizontal section.

[0011] Furthermore, the end of the shotcrete channel is perpendicular to the turning section, and the shotcrete head is a bent head with its outlet parallel to the horizontal section.

[0012] Furthermore, the drill rod is divided into two identical and interlocking rod bodies, which are connected by fasteners. Each rod body is equipped with a helical blade and a jetting blade.

[0013] Furthermore, the bottom edge and outer edge of the spiral blade are provided with first cutting teeth, and the turning section of the spray blade is provided with second cutting teeth.

[0014] Furthermore, the slewing radius of the shotcrete head is not greater than the rotary drilling radius of the helical blade.

[0015] The present invention also provides a composite pile formed by rotary drilling using the above-mentioned jetting drill bit, comprising a water-stop curtain and a cast-in-place pile located at the center of the water-stop curtain, wherein the inner diameter of the water-stop curtain matches the rotation diameter of the jetting head, and its outer diameter matches the rotary drilling diameter of the jetting blade.

[0016] Compared with the prior art, the beneficial effects of this utility model are:

[0017] 1. The grouting drill bit in this utility model can form a hollow cement mixing pile by grouting the outer part of the hole during rotary drilling. This not only simplifies the construction process, but also reduces the amount of cement used.

[0018] 2. The grouting drill bit in this utility model adopts a turning blade and the grouting head is set at the turning point. This not only enables the cement mortar to mix better with the outer sand to form a hollow cement mixing pile, but also enables the blade teeth to effectively avoid the sprayed cement mortar.

[0019] 3. The composite piles in this utility model have good pile formation effect, strong bonding force between cement mixing piles and cast-in-place piles, and higher durability. Attached Figure Description

[0020] Figure 1 This is a schematic diagram of foundation pit support in existing technology;

[0021] Figure 2 This is a three-dimensional structural view of Embodiment 1;

[0022] Figure 3 This is a front view of the structure of Embodiment 1;

[0023] Figure 4 for Figure 3 Structural sectional view along the AA direction;

[0024] Figure 5 This is a schematic diagram of the construction process in Example 1;

[0025] Figure 6 This is a three-dimensional structural view of Example 2;

[0026] Figure 7 This is a schematic diagram of Example 3.

[0027] Reference numerals in the attached diagram: 1. Drill rod; 2. Spiral blade; 3. Jetting blade; 4. Jetting head; 5. Jetting channel; 6. First cutter tooth; 7. Second cutter tooth; 8. Divided rod body; 9. Fastener; 10. Upper rod section; 11. Lower rod section; 12. Water-stop curtain; 13. Cast-in-place pile; 14. Horizontal section; 15. Turning section. Detailed Implementation

[0028] The technical solutions of the embodiments of this utility model will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this utility model, and not all embodiments. Based on the embodiments of this utility model, all other embodiments obtained by those skilled in the art without creative effort are within the protection scope of this utility model. Example

[0029] like Figures 2 to 4 As shown, a shotcrete drill bit includes a drill rod 1, a spiral blade 2 disposed at the bottom of the drill rod 1, shotcrete blades 3 disposed on the body of the drill rod 1, and a shotcrete head 4 disposed on the shotcrete blades 3. The shotcrete blades 3 are curved structures that bend backward in the middle. The shotcrete head 4 is disposed at the leading edge of the bend of the shotcrete blades 3. The shotcrete blades 3 are provided with a shotcrete channel 5 connecting the shotcrete head 4 and the internal channel of the drill rod 1. The radius of the spiral blades 2 increases sequentially from bottom to top. There are two spiral blades 2 and two shotcrete blades 3, which are evenly distributed around the circumference.

[0030] As a preferred example, the shotcrete blade 3 includes an integrally connected horizontal section 14 and a turning section 15, with an obtuse angle between the horizontal section 14 and the turning section 15, and the shotcrete channel 5 is located in the horizontal section 14. The purpose of this arrangement of the horizontal section and the turning section is to extend the cutting line and increase the contact surface of the cement slurry.

[0031] As a preferred example, the end of the shotcrete channel 5 is perpendicular to the turning section 15, and the shotcrete head 4 is a bent head with its outlet parallel to the horizontal section 14.

[0032] As a preferred embodiment, the bottom edge and outer edge of the helical blade 2 are provided with first cutting teeth 6, and the turning section 15 of the spraying blade 3 is provided with second cutting teeth 7. The first cutting teeth 6 on the bottom edge of the helical blade 2 always contact the end face of the soil, thereby realizing the excavation of the entire drill bit. The first cutting teeth 6 on the outer edge of the helical blade 2 are used to construct the center hole of the cement mixing pile. The second cutting teeth 7 on the spraying blade 3 are used to construct the outer circular surface hole of the cement mixing pile.

[0033] As a preferred example, the slewing radius of the shotcrete head 4 is not greater than the rotary drilling radius of the spiral blade 2.

[0034] like Figure 5 As shown, during the drilling process, the first cutting tooth 6 on the spiral blade 2 provides downward rotary drilling force, while the second cutting tooth 7 on the jetting blade 3 is responsible for rotary drilling to the maximum inner diameter. The jetting head 4 sprays cement mortar onto the borehole wall to form a water-stop curtain 12 of a certain thickness. After rotary drilling is completed, the jetting drill bit is withdrawn, a reinforcing cage is placed into the central hole of the water-stop curtain 12, and then concrete is poured to obtain the composite pile. Example

[0035] like Figure 6 As shown, this embodiment differs from Embodiment 1 in that, in this embodiment, the drill rod 1 is divided into two structurally identical and interconnected rod bodies 8, connected by fasteners 9. Each rod body is equipped with a helical blade 2 and a grouting blade 3. The rod body 8 is divided into an upper rod section 10 and a lower rod section 11. The helical blade 2 is located on the lower rod section 11, and the grouting blade 3 is located on the upper rod section 10. The cross-sections of both the upper rod section 10 and the lower rod section 11 are semi-circular, and they are connected at a 90° angle to each other in the circumferential direction. The bottom of the internal cavity of the drill rod 1 ends at the connection surface between the upper rod section 10 and the lower rod section 11. The advantage of this split connection is that it facilitates the installation of the grouting pipe. That is, when using this scheme, the internal cavity of the drill rod 1 no longer serves as a channel for conveying cement mortar, but rather as a cavity for accommodating the pipe for conveying cement mortar. Example

[0036] like Figure 7As shown, this embodiment also provides a composite pile constructed using the jet grouting drill bit described in Embodiments 1 and 2. The composite pile includes a water-stop curtain 12 and a cast-in-place pile 13 located at the center of the water-stop curtain 12. The inner diameter of the water-stop curtain 12 matches the rotation diameter of the jet grouting head 4, and its outer diameter matches the rotary drilling diameter of the jet grouting blade 3. The composite piles are staggered to form a foundation pit support. During construction, the first pile is constructed using the jet grouting drill bit, and then the remaining composite piles are constructed sequentially. The width of the interlocking portion between two adjacent composite piles is not greater than the width of the water-stop curtain 12.

[0037] Any aspects of this utility model not described in detail are well-known technologies to those skilled in the art.

[0038] It should be noted that the above specific embodiments are only used to illustrate the technical solution of this utility model and are not intended to limit it. Although this utility model has been described in detail with reference to the embodiments, those skilled in the art should understand that modifications and equivalent substitutions can be made to the technical solution of this utility model without departing from the spirit and scope of the technical solution of this utility model, and all such modifications and substitutions should be covered within the scope of the claims of this utility model.

Claims

1. A shotcrete drill bit, comprising a drill rod (1), a spiral blade (2) disposed at the bottom of the drill rod (1), a shotcrete blade (3) disposed on the body of the drill rod (1), and a shotcrete head (4) disposed on the shotcrete blade (3), characterized in that: The jetting blade (3) is a twisted structure that turns backward in the middle. The jetting head (4) is located at the leading edge of the turning point of the jetting blade (3). The jetting blade (3) is provided with a jetting channel (5) that connects the jetting head (4) and the internal channel of the drill rod (1).

2. The shotcrete drill bit according to claim 1, characterized in that: The spray blade (3) includes an integrally connected horizontal section (14) and a turning section (15), the angle between the horizontal section (14) and the turning section (15) is an obtuse angle, and the spray channel (5) is located in the horizontal section (14).

3. A shotcrete drill bit according to claim 2, characterized in that: The end of the shotcrete channel (5) is perpendicular to the turning section (15), and the shotcrete head (4) is a bent head with its outlet parallel to the horizontal section (14).

4. A shotcrete drill bit according to claim 1, characterized in that: The drill rod (1) is divided into two identical and interlocking rod bodies (8). The two rod bodies are connected by fasteners (9). Each rod body is provided with a spiral blade (2) and a jetting blade (3).

5. A shotcrete drill bit according to claim 2, characterized in that: The bottom edge and outer edge of the spiral blade (2) are provided with first cutting teeth (6), and the turning section (15) of the spray blade (3) is provided with second cutting teeth (7).

6. A shotcrete drill bit according to claim 1, characterized in that: The gyration radius of the shotcrete head (4) is not greater than the rotary drilling radius of the spiral blade (2).

7. A composite pile drilled using a jet grouting drill bit as described in claim 1, characterized in that: It includes a water-stop curtain (12) and a grouting pile (13) located at the center of the water-stop curtain (12). The inner diameter of the water-stop curtain (12) matches the rotation diameter of the grouting head (4), and its outer diameter matches the rotary drilling diameter of the grouting blade (3).

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