A drilling bit for mixing piles and a method for constructing mixing piles.

Abstract

This invention discloses a drilling bit for cement mixing piles and a method for constructing cement mixing piles. The inverted cup-shaped cement mixing pile is a concentric cement mixing pile structure with a solid top and a hollow bottom. The corresponding drilling bit includes a drill bit body, which is cylindrical; fixed blades, which are fixedly installed on the outside of the drill bit body; movable blades, which are hinged to the inside of the drill bit body via a one-way hinge. Rotation of the drill bit body in the forward direction causes the movable blades to retract, and rotation of the drill bit body in the reverse direction causes the movable blades to extend; and a grouting pipe, which is embedded in the drill bit body, with its end protruding from the end of the drill bit body. This invention enables the construction of tubular piles using a tubular drill bit body. Furthermore, by changing the rotation direction of the drill bit body, the contraction or extension of the internal movable blades can be controlled, thereby achieving a transition between solid and hollow piles, and completing the pile in one step. This invention relates to the field of civil engineering technology.

Description

Technical Field

[0001] This invention relates to an inverted cup-shaped mixing pile, a mixing pile drill bit, and a mixing pile construction method in the field of civil engineering technology. Background Technology

[0002] Cement mixing piles are constructed by injecting cement, lime, and other reinforcing materials into the foundation using a specialized mixer. The rotating drill blades forcefully mix the reinforcing material with the in-situ foundation soil, resulting in a uniform mixture. This process causes a series of reactions, including consolidation and hydration, between the foundation soil and the reinforcing material, transforming soft clay into a cylindrical pile with sufficient strength. This method is commonly used in soft soil foundation construction. The forced mechanical mixing of cement and soft soil forms cement-soil mixtures, based on a series of physical and chemical reactions between the two. Because cement and soft soil have poor fluidity, forced mixing is necessary to promote the reaction.

[0003] Generally, conventional cement mixing piles employ a unidirectional mixing process, with the mixing drill bit rotating in one direction to form a cylindrical mixing pile. Mixing piles are formed in a single operation, resulting in high construction efficiency. Furthermore, to meet the stress requirements of mixing piles, variable-diameter mixing piles, such as nail-shaped mixing piles, are also used. These piles have a larger upper diameter and a smaller lower diameter, forming a cement mixing pile similar to an anchor. Nail-shaped cement mixing piles effectively reinforce layers with high additional stress, creating a structure similar to an anchor with a high replacement rate at the top and a low replacement rate at the bottom.

[0004] However, the foundations of large buildings typically use multiple cement mixing piles for support. As the number of piles increases, the amount of cement consumed becomes staggering, leading to higher construction costs. Moreover, while current variable-diameter cement mixing piles can save some cement, under eccentric loads, due to their low shear strength, nail-shaped cement mixing piles are prone to breakage or cracking at the diameter change points, affecting the overall stress distribution of the piles. Summary of the Invention

[0005] The purpose of this invention is to at least solve one of the technical problems existing in the prior art, and to provide an inverted cup-shaped mixing pile, a mixing pile drill bit and a mixing pile construction method, which can save cement consumption and improve the shear strength of the mixing pile.

[0006] According to a first aspect of the present invention, an inverted cup-shaped mixing pile is provided, comprising a solid part and a hollow part, wherein the solid part is a solid cylinder and the hollow part is a hollow cylinder, the outer diameters of the solid part and the hollow part are equal, the solid part and the hollow part are an integral structure and the solid part is located at the top of the hollow part.

[0007] According to a first aspect of the present invention, the thickness between the inner and outer walls of the hollow portion is 0.2 to 0.4 meters, and the outer diameter of the inverted cup-shaped mixing pile is 0.8 to 1.2 meters.

[0008] According to a second aspect of the present invention, a mixing pile drill bit is provided, comprising:

[0009] The drill bit body is cylindrical in shape.

[0010] Fixed blades are fixedly installed on the outside of the drill bit body;

[0011] The movable blade is hinged to the inside of the drill bit body via a one-way hinge. Rotation of the drill bit body in the forward direction can retract the movable blade, and rotation of the drill bit body in the reverse direction can extend the movable blade.

[0012] A grouting pipe is embedded in the drill bit body, with its end protruding from the end of the drill bit body.

[0013] According to a second aspect of the present invention, the number of fixed blades is at least two, and the fixed blades are arranged in a circumferential array around the axis of the drill bit body.

[0014] According to a second aspect of the present invention, the number of fixed blades is further four.

[0015] According to a second aspect of the present invention, the number of movable blades is at least two, the movable blades are arranged in a circumferential array around the axis of the drill bit body, and the unidirectional hinges are all arranged in the same direction.

[0016] According to a second aspect of the present invention, the number of movable blades is further four.

[0017] According to a second aspect of the present invention, the number of grouting pipes is two and they are symmetrically arranged in the drill bit body.

[0018] According to a third aspect of the present invention, a method for constructing mixing piles is provided, comprising:

[0019] Install the mixing pile drill bit onto the drilling rig, and move the drilling rig to the designed hole position to prepare for construction;

[0020] The drill bit body rotates forward and drills into the ground, while the movable blades are in a retracted state;

[0021] When the drill bit body approaches the ground, it begins to send grout into the grouting pipe and continues drilling until it reaches the bottom of the pile.

[0022] The drill bit body rotates forward and is lifted towards the ground, generating the hollow section;

[0023] The drill bit body rotates in the opposite direction, the movable blades are in an extended state, and it continues to be lifted to the ground to generate the solid part, thus completing the construction of the inverted cup-shaped mixing pile.

[0024] According to a third aspect of the present invention, after the drill bit body rotates in the opposite direction and is lifted to the ground, it drills in the opposite direction to the bottom of the solid part and is lifted again, and the solid part is stirred back and forth an additional time to increase the strength of the solid part.

[0025] The beneficial effects of the embodiments of the present invention include at least the following: the present invention can construct tubular piles through the tubular drill bit body, and by changing the rotation direction of the drill bit body, the internal moving blades can be controlled to contract or extend, thereby realizing the transition between solid piles and hollow piles, and forming a pile in one step. Attached Figure Description

[0026] To more clearly illustrate the technical solutions in the embodiments of the present invention, the accompanying drawings used in the description of the embodiments will be briefly explained below. Obviously, the described drawings are only a part of the embodiments of the present invention, and not all of them. Those skilled in the art can obtain other design schemes and drawings based on these drawings without creative effort.

[0027] Figure 1 This is a structural diagram of a first aspect embodiment of the present invention;

[0028] Figure 2 This is a structural diagram of a second aspect embodiment of the present invention;

[0029] Figure 3 This is a schematic diagram illustrating the operation of a second aspect embodiment of the present invention;

[0030] Figure 4 This is a schematic diagram of a third aspect embodiment of the present invention.

[0031] Reference numerals: 100-solid part, 200-hollow part, 300-drill bit body, 400-fixed blade, 500-moving blade, 510-one-way hinge, 600-grouting pipe. Detailed Implementation

[0032] This section will describe in detail specific embodiments of the present invention. Preferred embodiments of the present invention are shown in the accompanying drawings. The purpose of the drawings is to supplement the textual description with graphics, so that people can intuitively and vividly understand each technical feature and overall technical solution of the present invention, but they should not be construed as limiting the scope of protection of the present invention.

[0033] In the description of this invention, it should be understood that the orientation descriptions, such as up, down, front, back, left, right, etc., are 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 limiting this invention.

[0034] In the description of this invention, "several" means one or more, "more than" means two or more, "greater than," "less than," and "exceeding" are understood to exclude the stated number, while "above," "below," and "within" are understood to include the stated number. The use of "first" and "second" in the description is merely for distinguishing technical features and should not be construed as indicating or implying relative importance, or implicitly indicating the number of indicated technical features, or implicitly indicating the order of the indicated technical features.

[0035] In the description of this invention, unless otherwise explicitly defined, terms such as "set up," "install," and "connect" should be interpreted broadly, and those skilled in the art can reasonably determine the specific meaning of the above terms in this invention in conjunction with the specific content of the technical solution.

[0036] The first aspect of this invention provides an inverted cup-shaped mixing pile. Since the bottom of the mixing pile primarily bears longitudinal pressure and less lateral shear force, the bottom of this inverted cup-shaped mixing pile is hollow, thereby reducing cement usage while meeting longitudinal load requirements. The top of the mixing pile needs to simultaneously bear both longitudinal pressure and lateral shear force; therefore, a hollow structure cannot be used, but rather a traditional solid pile structure is employed. The overall shape of this inverted cup-shaped mixing pile resembles an inverted cup, which allows for reduced cement usage while meeting load-bearing requirements, thereby lowering construction costs.

[0037] A second aspect of this invention provides a tubular drill bit for constructing the hollow portion of an inverted cup-shaped mixing pile. Fixed blades are located on the outer side of the drill bit body for mixing the outer soil. Movable blades are hinged inside the drill bit body. When the drill bit body rotates clockwise, the movable blades retract and do not mix the soil, suitable for constructing the hollow portion. When the drill bit body rotates counterclockwise, the movable blades extend and mix the soil, allowing mixing of the soil on both the inner and outer sides of the drill bit body, suitable for constructing the solid portion. By changing the rotation direction of the drill bit body, it is possible to switch between hollow pile construction and solid pile construction, simplifying construction and enabling pile formation in a single operation, thus improving construction efficiency.

[0038] The third aspect of the present invention provides a method for constructing a mixing pile, specifically describing the construction process of constructing the inverted cup-shaped mixing pile using the mixing pile drill bit.

[0039] Instruction manual attached Figure 1The structural diagram of this inverted cup-shaped mixing pile is shown. This inverted cup-shaped mixing pile includes a solid part 100 at the top and a hollow part 200 at the bottom. These two parts are concentric and integral, and their outer diameters are equal. Therefore, when the outer surface of this inverted cup-shaped mixing pile is subjected to lateral shear force, stress concentration will not occur on the outside, preventing breakage or cracking. The empty portion in the hollow part 200 is hole-shaped, located in the center of the hollow part 200, and coaxially arranged with it.

[0040] Instruction manual attached Figure 2 The structural diagram of this mixing pile drill bit is shown. The drill bit body 300 is cylindrical and hollow inside. Two grouting pipes 600 are embedded in the drill bit body 300, with the ends of the grouting pipes 600 protruding from the ends of the drill bit body 300, enabling simultaneous drilling and grouting. Four fixed blades 400 are installed on the outer side of the drill bit body 300, arranged in a circumferential array around the central axis of the drill bit body 300, with the extended surface of any fixed blade 400 passing through the central axis of the drill bit body 300, thereby increasing the mixing area. Four movable blades 500 are installed on the inner side of the drill bit body 300, each movable blade 500 being hinged to the drill bit body 300 by a one-way hinge 510. The one-way hinge 510 is a hinge that can only rotate in one of two directions, clockwise or counterclockwise, around the hinge axis. In this application, "forward" refers to the direction in which the one-way hinge 510 can rotate freely, and "reverse" refers to the direction in which the one-way hinge 510 is restricted and cannot continue to rotate.

[0041] Instruction manual attached Figure 3 A schematic diagram of the working process of this soil mixing pile drill bit is shown. When the drill bit body 300 rotates forward, its internal movable blades 500 are overturned and flattened against the inner wall of the drill bit body 300 due to soil resistance. This prevents the mixing of the soil inside the pile; only the fixed blades 400 on the outside of the drill bit body 300 perform the mixing, resulting in a hollow pile structure. When the drill bit body 300 rotates in the reverse direction, the movable blades 500 are overturned due to soil resistance, but are fixed in the center of the drill bit body 300 by the one-way hinge 510. These blades can then mix the soil inside the drill bit body 300, resulting in a solid pile structure.

[0042] Instruction manual attached Figure 4The construction method of this inverted cup-shaped soil mixing pile is demonstrated. After the mixing pile drill bit reaches the predetermined position (step a), the drill bit body 300 rotates clockwise and drills into the soil to the predetermined depth (steps b to c). Then, the drill bit body 300 rotates clockwise and is lifted. Since the movable blades 400 are in a contracted state when the drill bit body 300 rotates clockwise, a hollow mixing pile structure is formed (steps d to e). After reaching the predetermined top position of the hollow part 200, the drill bit body 300 rotates counterclockwise and continues to be lifted to the ground. The movable blades 400 are in an extended state, forming a solid mixing pile structure, obtaining the solid part 100 (step f). To strengthen the structural strength of the solid part 100, the drill bit body 300 drills again to the bottom of the solid part 100 and is lifted, and the soil at the solid part 100 is mixed again (steps g to h).

[0043] Reference Figure 1 The inverted cup-shaped mixing pile in the first aspect embodiment of the present invention includes a solid part 100 and a hollow part 200, which are integrally formed. The solid part 100 is a solid cylinder, and the hollow part 200 is a hollow cylinder, with the hollow portion of the hollow part 200 having a circular hole shape, the axis of which coincides with the central axis of the hollow part 200. The solid part 100 is located at the top of the hollow part 200, and the outer diameters of both are equal, thereby avoiding stress concentration at abrupt changes in outer diameter due to differences in outer diameter.

[0044] Furthermore, the thickness of the hollow part 200 and the thickness between the inner and outer walls is 0.2~0.4 meters, and the outer diameter of the inverted cup-shaped mixing pile is 0.8~1.2m, to avoid insufficient structural strength due to excessive thinness or excessive cement consumption due to excessive thickness.

[0045] Reference Figure 2 The mixing pile drill bit in the second aspect embodiment of the present invention includes a drill bit body 300, a fixed blade 400, a movable blade 500, and a grouting pipe 600. The drill bit body 300 is the main structure of the mixing pile brick and is in the shape of a cylindrical tube. (See attached specification.) Figure 2 Only the end of the drill bit body 300 is shown. Fixed blades 400 are fixedly installed on the outside of the drill bit body 300. In order to improve the stirring efficiency, the number of fixed blades 400 is at least two, preferably four, which are distributed in pairs and arranged in a circumferential array around the axis of the drill bit body 300. This can make the stirring force uniform and reduce the vibration or displacement of the drill bit body 300 due to uneven force.

[0046] The movable blades 500 are hinged to the inner side of the drill bit body 300 via one-way hinges 510. There are at least two of them, preferably four, and they are arranged in a circular array around the axis of the drill bit body 300. The one-way hinges 510 are all set in the same direction, so that when the drill bit body 300 rotates in the forward or reverse direction, the working state of each one-way hinge 510 is consistent.

[0047] Reference Figure 3 When the drill bit body 300 rotates clockwise, the movable blade 500 is overturned by the resistance of the soil and falls to the inner wall of the drill bit body 300, without mixing the soil. This results in a hollow pile structure as the soil inside is not consolidated due to the lack of mixing. When the drill bit body 300 rotates counterclockwise, the movable blade 500 flips to the center of the drill bit body 300 and is locked by the one-way hinge 510, thus enabling soil mixing and forming a solid pile structure.

[0048] The grouting pipe 600 is embedded within the drill bit body 300, without obstructing the normal drilling and lifting of the drill bit body 300. Furthermore, the end of the grouting pipe 600 protrudes from the end of the drill bit body 300, enabling grouting while drilling. To improve grouting efficiency, two grouting pipes 600 are used, symmetrically arranged within the drill bit body 300.

[0049] Reference Figure 4 The method for constructing mixing piles according to a third aspect of the present invention includes:

[0050] S1. Referring to step a, install the mixing pile drill bit onto the drilling rig, and move the drilling rig to the designed hole position to prepare for construction;

[0051] S2. Referring to step b, the drill bit body 300 rotates in the forward direction and drills into the ground at a drilling speed of no more than 0.8 m / min. While drilling, the outer soil is vigorously stirred. The movable blade 500 is in a retracted state and therefore does not stir the inner soil.

[0052] S3. When the drill bit body 300 approaches the ground, start sending grout into the grouting pipe 600. The grouting pressure is controlled at 0.2~0.5MPa. Referring to step c, the drill bit body 300 continues to drill until it reaches the bottom of the pile.

[0053] S4. Referring to steps d to e, the drill bit body 300 continues to rotate in the forward direction and is lifted towards the ground at a speed not exceeding 0.8 m / min, generating a hollow part 200;

[0054] S5. Referring to step f, the drill bit body 300 rotates in the opposite direction, the movable blade 500 is in the extended state, and continues to be lifted to the ground at a lifting speed of no more than 0.8 m / min. The solid part 100 is generated by the fixed blade 400 and the movable blade 500 working together to mix the soil, and the construction of the inverted cup-shaped mixing pile is completed.

[0055] Furthermore, after the drill bit body 300 rotates in the opposite direction and is lifted to the ground, it performs another round-trip forced mixing on the solid pile portion. The drill bit body 300 drills in the opposite direction to the bottom of the solid part 100 and is lifted again at a speed not exceeding 0.8 m / min to perform secondary mixing on the solid part 100, thereby improving the structural strength of the solid part 100.

[0056] The above is a detailed description of the preferred embodiments of the present invention. However, the present invention is not limited to the embodiments described. Those skilled in the art can make various equivalent modifications or substitutions without departing from the spirit of the present invention. All such equivalent modifications or substitutions are included within the scope defined by the claims of this application.

Claims

1. A mixing pile drill bit for forming an inverted cup-shaped mixing pile, characterized in that, include: The drill bit body is cylindrical in shape. Fixed blades are fixedly installed on the outside of the drill bit body; The movable blade is hinged to the inside of the drill bit body via a one-way hinge. Rotation of the drill bit body in the forward direction can retract the movable blade, and rotation of the drill bit body in the reverse direction can extend the movable blade. A grouting pipe is embedded in the drill bit body, with its end protruding from the end of the drill bit body. The inverted cup-shaped mixing pile is formed by forcibly mixing the reinforcing material with the in-situ foundation soil. It includes a solid part and a hollow part. The solid part is a solid cylinder, and the hollow part is a hollow cylinder. The outer diameters of the solid part and the hollow part are equal. The solid part and the hollow part are a concentric integral structure, and the solid part is located at the top of the hollow part. The thickness between the inner and outer walls of the hollow section is 0.2 to 0.4 meters, and the outer diameter of the inverted cup-shaped mixing pile is 0.8 to 1.2 meters.

2. The mixing pile drill bit according to claim 1, characterized in that: The number of fixed blades is at least two, and the fixed blades are arranged in a circumferential array around the axis of the drill bit body.

3. The mixing pile drill bit according to claim 2, characterized in that: The number of fixed blades is four.

4. The mixing pile drill bit according to claim 1, characterized in that: The number of movable blades is at least two, and the movable blades are arranged in a circumferential array around the axis of the drill bit body. The unidirectional hinges are all arranged in the same direction.

5. The mixing pile drill bit according to claim 4, characterized in that: The number of movable blades is four.

6. The mixing pile drill bit according to claim 1, characterized in that: The number of grouting pipes is two, and they are symmetrically arranged in the drill bit body.

7. A method for constructing mixing piles, using the mixing pile drill bit according to any one of claims 1 to 6, characterized in that, include: Install the mixing pile drill bit onto the drilling rig, and move the drilling rig to the designed hole position to prepare for construction; The drill bit body rotates forward and drills into the ground, while the movable blades are in a retracted state; When the drill bit body approaches the ground, it begins to send grout into the grouting pipe and continues drilling until it reaches the bottom of the pile. The drill bit body rotates forward and is lifted towards the ground, generating the hollow section; The drill bit body rotates in the opposite direction, the movable blades are in an extended state, and it continues to be lifted to the ground to generate the solid part, thus completing the construction of the inverted cup-shaped mixing pile.

8. The method for constructing mixing piles according to claim 7, characterized in that: After the drill bit body rotates in the opposite direction and is lifted to the ground, it drills in the opposite direction to the bottom of the solid part and is lifted again, and the solid part is stirred back and forth an additional time to increase the strength of the solid part.

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