Combined bidirectional intermixing device and mixing pile with enlarged head

Abstract

This utility model discloses a combined bidirectional mixing device and a mixing pile with an enlarged head. The upper end of the first upper outer drill rod is connected to the first power head, and the lower end of the first upper outer drill rod is fixed to the upper end of the first mixing frame of the mixing head of the upper enlarged head. The upper end of the first lower outer drill rod is fixed to the lower end of the first mixing frame of the mixing head of the upper enlarged head, and the lower end of the first lower outer drill rod is fixed to the upper end of the second mixing frame of the mixing head of the lower enlarged head. The first inner drill rod is rotatably fitted inside the first upper outer drill rod and the first lower outer drill rod. The upper end of the first inner drill rod is connected to the first power head, and the lower end of the first inner drill rod is rotatably fitted to the first lower connecting sleeve of the second mixing frame of the lower enlarged head. The lower end of the second outer drill rod is fixed to the upper end of the mixing head of the mixing pile, and the lower end of the second inner drill rod is rotatably fitted to the second lower connecting sleeve of the third mixing frame of the mixing pile. This device has a simple structure, stable and reliable construction process, and accurate and regular pile diameter.

Description

Technical Field

[0001] This utility model relates to the field of pile driver technology, specifically a combined bidirectional mixing device and a mixing pile with an enlarged head. Background Technology

[0002] The existing cement-soil mixing pile is simply called a mixing pile. The pile driver for mixing piles is relatively mature. During construction, the hoisting equipment drives the power head to rotate and drill through the mixing drill bit to stir the soil. At the same time, cement slurry is sprayed out through the slurry pipe in the drill rod and the nozzle on the mixing drill bit. After the cement slurry solidifies, it becomes a mixing pile.

[0003] Existing drill rod technology has evolved from unidirectional rotation to bidirectional rotation of the inner and outer drill rods; while existing mixing drill bits have evolved from unidirectional rotation and bidirectional rotation of the upper and lower mixing blades to bidirectional mixing drill bits composed of inner blades and a mixing frame with fixed outer blades in the same height range.

[0004] In existing technologies, the reinforcement of large-area soft soil foundations, such as soft soil subgrades of highways and high-grade roads, soft soil foundations of airport runways, and soft soil foundations of urban plazas, uses different equipment for settlement prevention and reinforcement, but each has its own shortcomings:

[0005] In the early stages, ordinary pile drivers were used to construct multiple mixing piles, such as 10-24 meters deep and 500mm-1000mm in diameter, which were arranged at intervals to form an anti-settlement structure for soft soil foundations. However, the disadvantages were obvious. If the density was too low, the settlement between the gaps would be uneven, and the anti-settlement reinforcement effect would be unsatisfactory. If the density was too high, too many mixing piles would be needed, the cost would be too high, and there would be too much waste of materials.

[0006] Later, technicians used a mixing equipment to first construct several mixing piles of conventional depth, and then construct a hardened layer composed of several meters deep cement-soil mixing piles on top of these mixing piles. The construction of the cement-soil mixing piles and the upper hardened layer with this equipment needs to be completed in two stages. In particular, the hardened layer composed of cement-soil mixing piles on top of the mixing piles needs to be constructed vertically with alternating shallow and deep sections and horizontally with repeated alternations. The equipment is relatively complex, the amount of construction is relatively large, the construction time is relatively long, the construction speed is relatively slow, and the cost of foundation treatment is relatively high.

[0007] Some technicians use bidirectional mixing drill bits to construct mixing piles, while simultaneously using high-pressure jet grouting devices to enlarge one or more large-diameter sections. However, high-pressure pressurization equipment has very high sealing requirements, and the pressure is difficult to stabilize. The diameter and regularity of the large-diameter section of the jet grouting are difficult to control accurately. In particular, soil collapse is prone to occur when the upper jet grouting enlarges the head, so it is impossible to place the enlarged head at the upper end of each mixing pile. Therefore, it is still difficult to achieve the intended reinforcement effect of preventing soft soil foundation settlement.

[0008] Some technicians use a method where the mixing drill bit rotates forward to determine the diameter of the mixing pile, and reverses to determine the enlarged diameter, to construct mixing piles with a T-shaped enlarged head at the top. Compared to existing technologies, this method improves the amount of work, construction time, construction speed, and foundation treatment costs. However, this type of pile driver is prone to mechanical failures, and there is a possibility that the mixing blades may not enlarge due to cement sticking to the soil or encountering obstacles such as rocks. This introduces uncertainty regarding the presence, shape, and size of the enlarged head, making it difficult to guarantee the reliability, stability, and accuracy of the construction process. Furthermore, the T-shaped enlarged head, with its right-angle transition to the mixing pile, has significantly insufficient compressive and shear strength, resulting in an unsatisfactory anti-settlement reinforcement effect.

[0009] Furthermore, when the mixing drill bit of all the above-mentioned mixing equipment is drilled to the lower section of the mixing pile, especially when it is close to the predetermined depth, the construction process is unstable due to the large distance between the mixing drill bit and the power head. The concentricity and verticality of the enlarged head of the pile and the lower section of the longer mixing pile are affected to a certain extent, which affects the pile quality and the pile bearing capacity.

[0010] Furthermore, none of the existing mixing equipment can produce mixing piles with double enlarged heads. Utility Model Content

[0011] One technical problem this utility model aims to solve is to provide a combined bidirectional mixing device with a simple structure, stable and reliable construction process, and low failure rate. The combined bidirectional mixing device can construct mixing piles with double-enlarged heads, ensuring that the diameter of the double-enlarged heads is accurate and regular, the concentricity and verticality of the double-enlarged heads and the mixing pile are good, and the compressive strength, shear strength and bearing capacity of the mixing piles with double-enlarged heads are greatly enhanced, resulting in a significant reinforcement effect against settlement of soft soil foundations.

[0012] One technical solution of this utility model is to provide a combined bidirectional stirring device.

[0013] The upper end of the first upper outer drill rod is connected to the first power head, and the lower end of the first upper outer drill rod is fixed to the upper end of the first stirring frame of the stirring head of the upper enlarged head.

[0014] The upper end of the first lower outer drill rod is fixed to the lower end of the first stirring frame of the stirring head of the upper enlarged head, and the lower end of the first lower outer drill rod is fixed to the upper end of the second stirring frame of the stirring head of the lower enlarged head.

[0015] The first upper outer drill pipe is coaxial with the first lower outer drill pipe;

[0016] The first inner drill rod is rotatably fitted inside the first upper outer drill rod and the first lower outer drill rod. The upper end of the first inner drill rod is connected to the first power head, and the lower end of the first inner drill rod is rotatably fitted to the first lower connecting sleeve of the second stirring frame of the lower enlarged head.

[0017] Above the first power head is a second power head. The upper end of the second outer drill rod is connected to the second power head. The first power head has a passage for the second outer drill rod to pass through. The second outer drill rod is slidably engaged with the first inner drill rod. The second inner drill rod is rotatably engaged with the second outer drill rod. The upper end of the second inner drill rod is connected to the second power head.

[0018] The lower end of the second outer drill rod is fixed to the upper end of the third mixing frame of the mixing head of the mixing pile, and the lower end of the second inner drill rod is rotatably engaged with the second lower connecting sleeve of the third mixing frame of the mixing head of the mixing pile.

[0019] The drill bit is located at the bottom end of the second inner drill rod below the mixing head of the mixing pile.

[0020] With the above structure, the combined bidirectional stirring device of this utility model has the following advantages:

[0021] This combined bidirectional mixing device completes one pile in a single drilling and mixing operation. It includes a long mixing pile at the bottom, a lower enlarged head in the middle, and an upper enlarged head at the top, also known as a mixing pile with double enlarged heads. This forms a reinforcement structure to prevent settlement of soft soil foundations. The equipment is relatively simple, the amount of construction work is relatively small, the construction time is relatively short, the construction speed is relatively fast, the construction efficiency is relatively high, the cement and energy consumption is relatively small, and the cost of soft soil foundation settlement prevention and reinforcement treatment is relatively low.

[0022] The constructed enlarged head, mixing pile, and frustum transition section connecting the enlarged head and mixing pile have small physical and mechanical errors, requiring only conventional rather than high-pressure grouting mechanisms. The failure rate of the grouting and mixing head is low, and the construction process is reliable, stable, and accurate. This ensures that the shape and size of the enlarged head are regular and accurate, allowing the complete and regular enlarged head to be accurately placed at the top of each mixing pile. Furthermore, the compressive strength, shear strength, and bearing capacity of the enlarged head, frustum transition section, and mixing pile are all significantly improved, resulting in a remarkable technical effect in the reinforcement treatment to prevent settlement of soft soil foundations.

[0023] Because the expansion head and the mixing pile produced by the combined bidirectional mixing device of this apparatus are connected by a frustum transition section, its compressive strength and shear strength are greatly improved.

[0024] This combined bidirectional mixing device ensures good uniformity in pile mixing because the mixing pile undergoes bidirectional interlocking through the mixing heads of the mixing pile bidirectional mixing device, while the lower enlarged head undergoes bidirectional interlocking twice through the mixing heads of the mixing pile bidirectional mixing device and the lower enlarged head bidirectional mixing device, and the upper enlarged head undergoes bidirectional interlocking three times through the mixing heads of the mixing pile, the lower enlarged head, and the upper enlarged head. This not only reduces cement consumption but also significantly improves the pile quality of the mixing pile and the double enlarged head, enhancing the remarkable technical effect of reinforcement treatment to prevent settlement of soft soil foundations.

[0025] This combined bidirectional mixing device has a significant technical advantage that is not found in any existing mixing pile equipment: because the first upper outer drill rod and the first lower outer drill rod are arranged vertically and on the same axis as a vertical line, and most of the length of the first inner drill rod is rotated within the first upper outer drill rod and the first lower outer drill rod, and part of the second outer drill rod is slidably fitted within the first inner drill rod, and most of the second inner drill rod is rotated within the second outer drill rod, the mixing pile construction process is stable. It can ensure good concentricity and verticality between the double enlarged head and the lower section of the mixing pile, greatly improving the pile quality and pile bearing capacity of the mixing pile and the double enlarged head, and further ensuring the significant technical effect of reinforcement treatment to prevent settlement of soft soil foundations.

[0026] Furthermore,

[0027] The stirring head of the upper enlarged head includes a first stirring frame and a first inner drill rod located in the stirring head section of the upper enlarged head. Multiple first outer stirring blades are fixed on the first stirring frame, and multiple first inner stirring blades are fixed on the first inner drill rod located in the stirring head section of the upper enlarged head. The first inner stirring blades and the first outer stirring blades are staggered in height and stir each other in opposite directions.

[0028] The stirring head of the lower enlarged head includes a second stirring frame and a first inner drill rod located in the stirring head section of the lower enlarged head. Multiple second outer stirring blades are fixed on the second stirring frame, and multiple second inner stirring blades are fixed on the first inner drill rod located in the stirring head section of the lower enlarged head. The second inner stirring blades and the second outer stirring blades are staggered in height and stir each other in opposite directions.

[0029] The mixing head of the mixing pile includes a third mixing frame and a second inner drill rod located in the mixing head section of the mixing pile. Multiple third outer mixing blades are fixed on the third mixing frame, and multiple third inner mixing blades are fixed on the second inner drill rod located in the mixing head section of the mixing pile. The third inner mixing blades and the third outer mixing blades are staggered in height and stir each other in opposite directions.

[0030] The use of the above-mentioned specific structures in the mixing heads of each pile ensures good uniformity of pile mixing, which can relatively reduce cement consumption and significantly improve the pile quality of mixing piles and double enlarged heads. It further enhances the compressive and shear resistance of the upper enlarged head, and further enhances the significant technical effect of reinforcement treatment to prevent settlement of soft soil foundations.

[0031] Furthermore, multiple first frame panels constitute the first mixing frame of the mixing head of the enlarged head: the multiple first frame panels are distributed circumferentially, the inner end of the first upper horizontal plate of each first frame panel is fixed to the lower end of the first upper outer drill rod, the outer end of the first upper horizontal plate is fixed to the upper end of the first vertical plate, the lower end of the first vertical plate is fixed to the upper end of the first inclined plate, and the lower end of the first inclined plate is fixed to the upper end of the first lower outer drill rod. With this structure, the bidirectional mixing of the upper enlarged head improves the uniformity of mixing, which can relatively reduce cement consumption and significantly improve the pile formation quality of the upper enlarged head, further enhancing its compressive and shear resistance.

[0032] Furthermore, multiple second frame panels constitute the second mixing frame of the mixing head of the lower enlarged head: the multiple second frame panels are distributed circumferentially; the inner end of the second upper horizontal plate of each second frame panel is fixed to the lower end of the second outer drill rod, the outer end of the second upper horizontal plate is fixed to the upper end of the second vertical plate, the lower end of the second vertical plate is fixed to the upper end of the second inclined plate, the lower end of the second inclined plate is fixed to the first lower connecting sleeve, and the first lower connecting sleeve is rotatably engaged with the lower end of the first inner drill rod. With this structure, the bidirectional mixing of the upper enlarged head improves the uniformity of mixing, which can relatively reduce cement consumption and significantly improve the pile formation quality of the upper enlarged head, further enhancing the compressive strength, shear strength, and bearing capacity of the lower enlarged head.

[0033] Furthermore, multiple third-frame panels constitute the third mixing frame of the mixing head of the mixing pile: the multiple third-frame panels are distributed circumferentially; the inner end of the third upper horizontal plate of each third-frame panel is fixed to the lower end of the second outer drill rod, the outer end of the third upper horizontal plate is fixed to the upper end of the third vertical plate, the lower end of the third vertical plate is fixed to the outer end of the third lower horizontal plate, the inner end of the third lower horizontal plate is fixed to the second lower connecting sleeve, and the second lower connecting sleeve is rotatably engaged with the lower end of the second inner drill rod. With this structure, the bidirectional mixing of the enlarged upper head improves the uniformity of mixing, which can relatively reduce cement consumption and significantly improve the pile formation quality of the enlarged upper head, further enhancing the bearing capacity of the mixing pile.

[0034] Another technical problem to be solved by this utility model is to provide a mixing pile with an enlarged head that has fast construction speed, relatively low cost of soft soil foundation reinforcement, significantly improved compressive and shear resistance, and significant effect on preventing settlement and reinforcing soft soil foundations.

[0035] Another technical solution of this utility model is to provide a mixing pile with an enlarged head. The mixing pile with the enlarged head is formed by mixing the pile with the above-mentioned combined bidirectional mixing device. The top is an upper enlarged head, the bottom of the upper enlarged head is a lower enlarged head, and the bottom of the lower enlarged head is a mixing pile. There are frustum transition sections between the upper and lower enlarged heads and between the lower enlarged head and the mixing pile, forming a mixing pile with double enlarged heads and frustum transition sections. There are multiple rows of mixing piles with enlarged heads and frustum transition sections, with multiple piles in each row. The upper enlarged heads of adjacent rows are staggered. There are gaps between adjacent upper enlarged heads, or adjacent upper enlarged heads are tangent to each other, or adjacent upper enlarged heads are interlocked.

[0036] With the above structure, the mixing pile with enlarged head of this utility model has the following advantages:

[0037] Because the upper enlarged head is placed at the top of the lower enlarged head, the coaxial double enlarged heads, namely the upper and lower enlarged heads and the mixing pile, can be constructed in one go, saving labor, time, and materials such as cement and electricity consumption. The construction efficiency is high, and the cost of soft soil foundation anti-settlement reinforcement treatment is relatively low.

[0038] Since the transition sections between the upper and lower enlarged heads, and between the lower enlarged head and the mixing pile, are all frustum-shaped transition sections, the compressive strength, shear strength, and bearing capacity of the mixing pile with double enlarged heads are greatly improved.

[0039] In particular, the horizontal arrangement of the upper enlarged heads is very reasonable. The enlarged heads in adjacent rows are staggered with each other, and according to the actual geological conditions and engineering needs, the upper enlarged heads can be spaced apart, tangent to each other, or interlocked, which makes the anti-settlement reinforcement effect of soft soil foundations significant.

[0040] Furthermore, the staggered arrangement refers to the fact that the diameter line of a circle of each enlarged head in a row is perpendicular to the line connecting the centers of two adjacent enlarged heads in an adjacent row, and the diameter line of this circle bisects the line connecting the centers. With this structure, the staggered arrangement is highly efficient, significantly improving the anti-settlement reinforcement effect on soft soil foundations and saving materials such as cement.

[0041] Furthermore, the gap between adjacent enlarged heads is 1mm-50mm. Using this structure, the gaps not only save on materials such as cement and electricity, but also ensure a significant anti-settlement reinforcement effect on the soft soil foundation.

[0042] Furthermore, the aforementioned frustum transition section is either a smooth frustum transition section or a stepped frustum transition section. By adopting the above structure, both types of frustum transition sections can significantly improve the compressive strength, shear strength, and bearing capacity of the mixing pile with the enlarged head. Attached Figure Description

[0043] Figure 1 This is a schematic diagram of the structure of a preferred embodiment of the combined bidirectional mixing device of this utility model when installed on a piling machine. Figure 1 The drill rods in the two middle sections are drawn with their lengths omitted; Figure 1 and Figure 12 The steel wire rope was omitted; Figure 1 , Figure 9 , Figure 10 and Figure 12 (Some bolts and nuts have been omitted).

[0044] Figure 2 yes Figure 1 A magnified structural diagram of A in the diagram.

[0045] Figure 3 yes Figure 2 Enlarged structural diagram after removing the equipment background and the second power head housing Figure 1 .

[0046] Figure 4 yes Figure 2 Enlarged structural diagram of the equipment background and the second power head housing (without background) Figure 2 (and Figure 3 (Different angles)

[0047] Figure 5 yes Figure 1 A magnified structural diagram of B in the diagram.

[0048] Figure 6 yes Figure 5 Enlarged structural diagram of the equipment without background and the first power head housing Figure 1 .

[0049] Figure 7 yes Figure 5 Enlarged structural diagram after removing the equipment background and the housing of the first power head Figure 2 (and Figure 6 (Different angles)

[0050] Figure 8 This is a structural schematic diagram showing the passageway of the second outer drill rod on the first power head and the inner hole of the first inner drill rod.

[0051] Figure 9 yes Figure 1 A magnified structural diagram of C.

[0052] Figure 10yes Figure 1 A magnified structural diagram of D in the diagram.

[0053] Figure 11 yes Figure 1 A magnified structural diagram of E in the middle.

[0054] Figure 12 This is a schematic diagram of the structure of the mixing pile constructed by the pile driver equipped with the combined bidirectional mixing device of this utility model (the height of the two drill rods is omitted; the enlarged head, the frustum transition surface and the cement and soil inside the mixing pile are omitted).

[0055] Figure 13 This is a schematic diagram of an embodiment of the present invention where adjacent enlarged heads of the mixing pile are tangent to each other.

[0056] Figure 14 This is a schematic diagram of an embodiment of the present invention where adjacent enlarged heads of the mixing pile have gaps between them (only the enlarged heads are shown).

[0057] Figure 15 This is a structural schematic diagram of an embodiment of the mixing pile of this utility model, in which adjacent enlarged heads interlock with each other (only the upper enlarged head and the first frustum transition section are shown).

[0058] Figure 16 This diagram shows a structural schematic of another type of frustum transition section, namely a stepped transition section, in this mixing pile with an enlarged head.

[0059] Figure 17 A schematic diagram of another type of inclined plate in this device, namely a stepped inclined plate, is shown.

[0060] As shown in the figure:

[0061] 1. Pile driver; 11. Traveling mechanism; 12. Construction platform; 13. Tower; 14. Winch mechanism; 15. Control room;

[0062] 21. Upper enlarged head stirring head; 211. First stirring frame; 2111. First outer stirring blade; 2112. First frame leaf; 21121. First upper horizontal plate; 21122. First upper connecting sleeve; 21123. First vertical plate; 21124. First inclined plate; 21125. First lower horizontal plate; 22. First upper outer drill rod; 23. First inner stirring blade;

[0063] 31. Lower enlarged head stirring head; 311. Second stirring frame; 3111. Second outer stirring blade; 3112. Second frame leaf; 31121. Second upper horizontal plate; 31122. Second upper connecting sleeve; 31123. Second vertical plate; 31124. Second inclined plate; 31125. First lower connecting sleeve; 32. First lower outer drill rod; 33. Second inner stirring blade; 34. First inner drill rod.

[0064] 41. Mixing head of mixing pile; 411. Third mixing frame; 4111. Third outer mixing blade; 4112. Third frame leaf; 41121. Third upper horizontal plate; 41122. Third upper connecting sleeve; 41123. Third vertical plate; 41124. Second lower horizontal plate; 41125. Second lower connecting sleeve; 42. Second outer drill rod; 43. Third inner mixing blade; 44. Second inner drill rod.

[0065] 5. First power head; 51. First power head housing; 52. First inner drill pipe motor; 53. First inner drill pipe gearbox; 54. First inner drill pipe drive gear; 55. First inner drill pipe driven gear; 56. First outer drill pipe motor; 57. First outer drill pipe gearbox; 58. First outer drill pipe drive gear; 59. First outer drill pipe driven gear; 510. Second outer drill pipe passageway;

[0066] 6. Second power head; 61. Second power head housing; 62. Second inner drill pipe motor; 63. Second inner drill pipe gearbox; 64. Second inner drill pipe drive gear; 65. Second inner drill pipe driven gear; 66. Second outer drill pipe motor; 67. Second outer drill pipe gearbox; 68. Second outer drill pipe drive gear; 69. Second outer drill pipe driven gear.

[0067] 7. Soil, 71. Upper enlarged head, 72. First truncated cone transition section, 73. Lower enlarged head, 74. Second truncated cone transition section, 75. Mixing pile, 76. Diameter line, 77. Center connection line, 78. Step transition section, 781. Step;

[0068] 8. Drill bit; 81. Drill tip; 82. Drill bit body; 83. Drill bit agitator blades;

[0069] 91. Connector; 92. Shotcrete nozzle;

[0070] 100. Inclined step slab. Detailed Implementation

[0071] The specific embodiments of this utility model will be further described below with reference to the accompanying drawings. It should be noted that these descriptions of specific embodiments are intended to aid in understanding this utility model, but do not constitute a limitation thereof. Furthermore, the technical features involved in the various specific embodiments of this utility model described below can be combined with each other as long as they do not conflict with each other.

[0072] like Figure 1 , Figure 2 , Figure 3 , Figure 4 , Figure 5 , Figure 6 , Figure 7 , Figure 8 , Figure 9 , Figure 10 , Figure 11 and Figure 12 As shown.

[0073] The existing pile driver 1 for constructing mixing piles may include a traveling mechanism 11, a construction platform 12, a tower 13 or column, a winch mechanism 14, and an operator's cab 15, etc.

[0074] In a preferred embodiment of the combined bidirectional mixing device of this utility model, the mixing head of the combined bidirectional mixing device consists of three mixing heads: one is an upper enlarged mixing head 21, one is a lower enlarged mixing head 31, and one is a mixing pile mixing head 41.

[0075] The upper end of the first upper outer drill rod 22 is connected to the first power head 5, and the lower end of the first upper outer drill rod 22 is fixed to the upper end of the first stirring frame 211 of the stirring head 21 of the upper enlarged head.

[0076] The upper end of the first lower outer drill rod 32 is fixed to the lower end of the first stirring frame 211 of the stirring head 21 of the upper enlarged head, and the lower end of the first lower outer drill rod 32 is fixed to the upper end of the second stirring frame 311 of the stirring head 31 of the lower enlarged head.

[0077] The first upper outer drill pipe 22 and the first lower outer drill pipe 32 are coaxial.

[0078] The first inner drill rod 34 is rotatably fitted inside the first upper outer drill rod 22 and the first lower outer drill rod 32. The upper end of the first inner drill rod 34 is connected to the first power head 5, and the lower end of the first inner drill rod 34 is rotatably fitted to the first lower connecting sleeve 31125 of the second stirring frame 311 of the stirring head 31 of the lower enlarged head.

[0079] Above the first power head 5 is the second power head 6. The upper end of the second outer drill rod 42 is connected to the second power head 6. The first power head 5 has a passage for the second outer drill rod to pass through, which can be called the second outer drill rod passage 510. The second outer drill rod 42 is in sliding engagement with the first inner drill rod 34, specifically, it is in sliding engagement with the inner hole 341 of the first inner drill rod 34. The second inner drill rod 44 is in rotatable engagement with the second outer drill rod 42. The upper end of the second inner drill rod 44 is connected to the second power head 6. The second outer drill rod passage 510 is generally set on the cover plate of the first power head 5. There are generally two structures: one is that the cover plate of the first power head 5 has a round through hole for the second outer drill rod 42 to pass through, and there is a gap between the second outer drill rod 42 and the wall of the through hole; the other is that it is hollow, with a larger space for the second outer drill rod to pass through. It is easy to understand that the upper end of the first inner drill rod 34 is on the first power head 5, and there is no obstruction between the inner hole 341 of the upper end of the first inner drill rod 34 and the second outer drill rod 510 on the cover plate of the first power head 5. Therefore, as long as the second outer drill rod 42 passes through the inner hole 341 of the first inner drill rod 34 and the second outer drill rod passage 510 on the cover plate of the first power head 5, it will pass through the first power head 5.

[0080] The lower end of the second outer drill rod 42 is fixed to the upper end of the third mixing frame 411 of the mixing head 41 of the mixing pile, and the lower end of the second inner drill rod 46 is rotatably engaged with the second lower connecting sleeve 41125 of the third mixing frame 411 of the mixing head 41 of the mixing pile.

[0081] The drill bit 8 is located at the bottom end of the second inner drill rod 44 below the mixing head 41 of the mixing pile. The drill bit 8 may include a drill tip 81 at the bottom end, such as a triangular plate drill tip 81, a drill bit body 82 at the upper end of the drill tip 81, and drill bit mixing blades 83 symmetrically arranged on both sides of the drill bit body 82.

[0082] The agitator 21 of the enlarged head includes a first agitator frame 211 and a first inner drill rod 34 located in the agitator head 21 section of the enlarged head. Multiple first outer agitator blades 2111 are fixed on the first agitator frame 2111, such as two blades for a total of six first outer agitator blades 2111 fixed on each first frame 2112. Each first frame 2112 may have one horizontal agitator blade and one oblique agitator blade. Multiple first inner agitator blades 23 are fixed on the first inner drill rod 34 located in the agitator head 21 section of the enlarged head, such as three blades for a total of nine blades 23 corresponding to the two first outer agitator blades 2111 in each frame. The first inner agitator blades 23 are staggered in height from the first outer agitator blades 2111 and stir towards each other. All first inner agitator blades 23 can be horizontal agitator blades.

[0083] The stirring head 31 of the lower enlarged head includes a second stirring frame 311 and a first inner drill rod 34 located in the stirring head 31 section of the lower enlarged head. Multiple second outer stirring blades 3111 are fixed on the second stirring frame 311, such as one blade on each of the second frame pages 3112 (described below), for a total of three second outer stirring blades 3111. Each second frame page 3112 may have one horizontal stirring blade. Multiple second inner stirring blades 33 are fixed on the first inner drill rod 34 located in the stirring head 31 section of the lower enlarged head, such as two blades corresponding to one second outer stirring blade 3111 in each frame, for a total of six second inner stirring blades 33. The second inner stirring blades 33 are staggered in height from the second outer stirring blades 3111 and stir each other in opposite directions. All second inner stirring blades 33 may be horizontal stirring blades.

[0084] The mixing head 41 of the mixing pile includes a third mixing frame 411 and a second inner drill rod 44 located in the mixing head 41 section of the mixing pile. Multiple third outer mixing blades 4111 are fixed on the third mixing frame 411, such as one blade on each of the third frame pages 4112 (described below), for a total of three third outer mixing blades 4111. Each third frame page 4112 may have one horizontal mixing blade. Multiple third inner mixing blades 43 are fixed on the second inner drill rod 44 located in the mixing head 41 section of the mixing pile, such as two blades corresponding to one third outer mixing blade 4111 in each page, for a total of six third inner mixing blades 43. The third inner mixing blades 43 and the third outer mixing blades 4111 are staggered in height and stir towards each other. All third inner mixing blades 43 may be horizontal mixing blades.

[0085] Multiple first frame pages 2112 constitute the first stirring frame 211 of the stirring head 21 of the enlarged head, such as three first frame pages 2112 constituting the first stirring frame 211 of the stirring head 21 of the enlarged head. The specific structure is described as follows: Multiple first frame pages 2112 are distributed along the circumference, preferably evenly distributed along the circumference, such as the angle between the width bisectors of two adjacent first frame pages 2112 being 120°; the inner end of the first upper horizontal plate 21121 of each first frame page 2112 is fixed to the lower end of the first upper outer drill rod 22, such as a first upper connecting sleeve 21122 fixed to the lower end of the first outer drill rod 22, and the first upper horizontal plate 21121 is fixed to the first upper connecting sleeve 21122. Of course, the first upper connecting sleeve can be omitted and the inner end of the first upper horizontal plate can be directly fixed to the lower end of the first outer drill rod; the outer end of the first upper horizontal plate 21121 is fixed to the upper end of the first vertical plate 21123, the lower end of the first vertical plate 21123 is fixed to the upper end of the first inclined plate 21124, and the lower end of the first inclined plate 21124 is fixed to the upper end of the first outer drill rod 32. The lower end of the first inclined plate 21124 is fixed to the upper end of the second drill rod 32. This can be achieved in two ways: the lower end of the first inclined plate 21124 is fixed to the outer end of the first lower horizontal plate 21125, and the inner end of the first lower horizontal plate 21125 is fixed to the upper end of the second outer drill rod 32; or, instead of the first lower horizontal plate, the lower end of the first inclined plate is directly fixed to the upper end of the second outer drill rod. The stirring head 21 of the upper enlarged head can be called the first stirring head. The stirring head 21 of the upper enlarged head is used to stir the large-diameter upper enlarged head 71 and the first frustum transition section 72.

[0086] Multiple second frame panels 3112 constitute the second stirring frame 311 of the stirring head 31 of the lower enlarged head, such as three second frame panels 3112 constituting the second stirring frame 311 of the stirring head 31 of the lower enlarged head. The specific structure is described as follows: the multiple second frame panels 3112 are distributed circumferentially, preferably evenly distributed circumferentially, such as the angle between the width bisectors of adjacent second frame panels 3112 being 120° to each other; the inner end of the second upper horizontal plate 31121 of each second frame panel 3112 is fixed to the lower end of the second outer drill rod 32, such as a second upper connecting sleeve 31122 fixed to the lower end of the second outer drill rod 32, and the inner end of the second upper horizontal plate 31121 fixed to the second upper connecting sleeve 31122. Alternatively, the second upper connecting sleeve can be omitted, and the inner end of the second upper horizontal plate can be directly fixed to the lower end of the second outer drill rod. The outer end of the second upper horizontal plate 31121 is fixed to the upper end of the second vertical plate 31123, the lower end of the second vertical plate 31123 is fixed to the upper end of the second inclined plate 31124, and the lower end of the second inclined plate 31124 is fixed to the first lower connecting sleeve 31225. This can be achieved in two ways: the lower end of the second inclined plate 31224 is directly fixed to the first lower connecting sleeve 31225, or the lower end of the second inclined plate is fixed to the outer end of a lower horizontal plate, with the inner end of the lower horizontal plate fixed to the first lower connecting sleeve. The first lower connecting sleeve 31225 is rotatably engaged with the lower end of the first inner drill rod 34. The stirring head 31 of the lower enlarged head can be called the second stirring head. The stirring head 31 of the lower enlarged head is used to stir the lower enlarged head 73 with its medium diameter and the transition section 74 of the second frustum.

[0087] Multiple third frame panels 4112 constitute the third mixing frame 411 of the mixing head 41 of the mixing pile, such as three third frame panels 4112 constituting the third mixing frame 411. The specific structure is described as follows: the multiple third frame panels 4112 are distributed along the circumference, preferably evenly distributed along the circumference, such as the included angle between the width bisectors of adjacent third frame panels 4112 being 120° to each other; the inner end of the third upper horizontal plate 41121 of each third frame panel 4112 is fixed to the lower end of the second outer drill rod 42, such as a third upper connecting sleeve 41122 fixed to the lower end of the second outer drill rod 42, and the inner end of the third upper horizontal plate 41121 is fixed to the third upper connecting sleeve 4112. 2. Alternatively, the third upper connecting sleeve can be omitted, and the inner end of the third upper horizontal plate can be directly fixed to the lower end of the second outer drill rod; the outer end of the third upper horizontal plate 41121 is fixed to the upper end of the third vertical plate 41123, the lower end of the third vertical plate 41123 is fixed to the outer end of the second lower horizontal plate 41124, and the inner end of the third lower horizontal plate 41124 is fixed to the second lower connecting sleeve 41125. The second lower connecting sleeve 41125 is rotatably engaged with the lower end of the second inner drill rod 44. The mixing head 41 of the mixing pile can be called the third mixing head. The mixing head 41 of the mixing pile is used to mix small-diameter mixing piles 75.

[0088] The frame, consisting of an upper horizontal plate, vertical plate, and inclined plate, is fixed to each other or to a lower horizontal plate. It can be a frame formed by bending a long strip of plate, with curved transitions between corners. The corners between the hinged upper enlarged head 71 and the first frustum transition section 72, and between the first frustum transition section 72 and the lower enlarged head 73, can all be curved. Similarly, the corners between the hinged lower enlarged head 73 and the second frustum transition section 74, and between the second frustum transition section and the mixing pile, can also be curved. Alternatively, adjacent plates can be welded together at right angles, with all corners being right angles. Or, adjacent plates can be welded together at right angles, but with a missing corner at the outer angle; all corners can be corners with an inner convex ring.

[0089] The fixing can be achieved by using multiple bolts or by welding.

[0090] In a preferred embodiment of the combined bidirectional stirring device of this utility model, the first power head 5 is individually connected to and driven by the wire rope of the winch mechanism 14 and is vertically slidably fitted onto the tower 13 of the pile driver 1. The second power head 6 is individually connected to and driven by the wire rope of the winch mechanism 14 and is vertically slidably fitted onto the tower 13 of the pile driver 1.

[0091] In a preferred embodiment of the combined bidirectional stirring device of this utility model, a grouting pipe fixed inside the second inner drill rod 44 may be included. The upper end of the grouting pipe may have a connector 91 for connecting to the grout inlet pipe. The grout inlet pipe is connected to a grout pump and a grout pool located on the ground. The lower end of the grouting pipe may be connected to multiple grouting nozzles 92 located on the drill bit body 82 of the drill bit 8.

[0092] The specific structure of the first power head 5 and the specific structure connecting the upper end of the first inner drill rod 34 and the upper end of the first outer drill rod 22 to the first power head 5 can be as follows: the lower ends of the first inner drill rod motor 52 and the first outer drill rod motor 56, each with its own gearbox, are vertically and parallelly fixed inside the first power head housing 51. The first inner drill rod drive gear 54, coaxially fixed on the output shaft of the first inner drill rod gearbox 53, meshes horizontally with the first inner drill rod driven gear 55, coaxially fixed on the upper end of the first inner drill rod 34. The first outer drill rod drive gear 58, coaxially fixed on the output shaft of the first outer drill rod gearbox 57, meshes horizontally with the first outer drill rod driven gear 59, coaxially fixed on the upper end of the first outer drill rod 22. Relatively speaking, the first outer drill rod driven gear 59 and the first outer drill rod drive gear 58 are at the bottom, and the first inner drill rod driven gear 55 and the first inner drill rod drive gear 54 are at the top.

[0093] The specific structure of the second power head 6 and the specific structure connecting the upper end of the second inner drill rod 44 and the upper end of the second outer drill rod 42 to the second power head 6 can be as follows: the lower ends of the second inner drill rod motor 62 and the second outer drill rod motor 66, each with its own gearbox, are vertically and parallelly fixed inside the second power head housing 61. The second inner drill rod drive gear 64, coaxially fixed on the output shaft of the second inner drill rod gearbox 63, meshes horizontally with the second inner drill rod driven gear 65, coaxially fixed on the upper end of the second inner drill rod 44. The second outer drill rod drive gear 68, coaxially fixed on the output shaft of the second outer drill rod gearbox 67, meshes horizontally with the second outer drill rod driven gear 69, coaxially fixed on the upper end of the second outer drill rod 42. Relatively speaking, the second outer drill rod driven gear 69 and the second outer drill rod drive gear 68 are below, and the second inner drill rod driven gear 65 and the second inner drill rod drive gear 64 are above.

[0094] like Figure 13 , Figure 14 , Figure 15 , Figure 16 and Figure 17 As shown.

[0095] In a preferred embodiment of the present invention, the mixing pile with enlarged head is formed by mixing the pile using the aforementioned combined bidirectional mixing device. The top is an upper enlarged head 71, the bottom of the upper enlarged head 71 is a lower enlarged head 73, the bottom of the lower enlarged head 73 is a mixing pile 75, a first frustum transition section 72 is between the upper enlarged head 71 and the lower enlarged head 73, and a second frustum transition section 74 is between the lower enlarged head 73 and the mixing pile 75, thus forming a mixing pile with double enlarged heads and frustum transition sections. From top to bottom: upper enlarged head 71, first frustum transition section 72, lower enlarged head 73, second frustum transition section 74, and mixing pile 75. The mixing piles with enlarged heads and frustum transition sections are arranged in multiple rows, with multiple piles in each row. The upper enlarged heads 71 ​​in adjacent rows are staggered. Adjacent upper enlarged heads 71 ​​are spaced apart, tangent to each other, or interlocked.

[0096] The staggered arrangement means that the diameter line 76 of a circle of each upper enlarged head 71 in a row is perpendicular to the line 77 connecting the centers of two adjacent upper enlarged heads 71 ​​in an adjacent row, and the diameter line 76 bisects the line 77 connecting the centers.

[0097] The gap size a between adjacent enlarged heads 71 ​​is 1mm-50mm.

[0098] The aforementioned frustum transition section is either a smooth frustum transition section or a stepped frustum transition section.

[0099] See Figure 12In a preferred embodiment of the combined bidirectional mixing device of this utility model, after installation on the piling machine 1, the following construction steps can be adopted:

[0100] 1) Control the walking mechanism 11 to align the axis of the drill bit 8 of the combined bidirectional mixing device of the pile driver 1 with the center of the enlarged head 71 on the soil body 7.

[0101] 2) Operation of the bidirectional mixing device for mixing piles: Power is turned on to make the second power head 61 rotate. At the same time, the winch mechanism 14 is controlled to drive the uppermost second power head 61 and drive the mixing head 41 and drill bit 8 of the bidirectional mixing pile at the bottom to drill down and mix through the second inner drill rod 44 and the second outer drill rod 42. Multiple grouting nozzles 92 on the drill bit 8 spray grout at the same time to construct the mixing pile 75.

[0102] Operating the bidirectional mixing device of the enlarged head: Turn on the power to make the first power head 5 rotate, and at the same time control the winch mechanism 14 to drive the first power head 5 located below the second power head 6, and drive the mixing head 31 of the lower enlarged head and the mixing head 21 of the upper enlarged head located above the mixing head 41 of the mixing pile to mix downwards, and construct the lower enlarged head 73 and the upper enlarged head 71.

[0103] It is easy to understand that the winch mechanism 14 drives the second power head 6 up or down. When driving it up, the wire rope is loosened and the second power head 6, the second inner drill rod 44, the second outer drill rod 42, and the mixing head 41 of the mixing pile are lowered by their own weight. The winch mechanism 14 also drives the first power head 5 up or down. When driving it up, the wire rope is loosened and the first power head 5, the first inner drill rod 34, the first upper outer drill rod 22, the first lower outer drill rod 32, the mixing head 21 of the upper enlarged head, and the mixing head 31 of the lower enlarged head are lowered by their own weight.

[0104] 3) Control: The mixing head 41 of the mixing pile moves downward to construct the mixing pile 75, while the mixing head 31 of the lower enlarged head moves downward to construct the lower enlarged head 73, and the mixing head 21 of the upper enlarged head moves downward to construct the upper enlarged head 71; or the mixing head 41 of the mixing pile moves downward to construct the mixing pile 75, while the mixing head 21 of the upper enlarged head and the mixing head 31 of the lower enlarged head rotate in place or stop in place; or when the mixing head 41 of the mixing pile has reached the predetermined depth, it rotates in place or stops in place, while the mixing head 21 of the upper enlarged head and the mixing head 31 of the lower enlarged head move downward to construct the double enlarged head, until the mixing pile 75 reaches the predetermined depth, and both the upper enlarged head 71 and the lower enlarged head 73 reach the predetermined depth.

[0105] 4) Operation: Stop spraying grout at the spray nozzle 92, and keep the mixing head 21 of the upper enlarged head, the mixing head 31 of the lower enlarged head, the mixing head 41 of the mixing pile, and the drill bit 8 rotating. The second power head 6 moves upward first to make room, and the first power head 5 moves upward later, or the second power head 6 and the first power head 5 move upward simultaneously, until the second power head 6, the first power head 5, the mixing head 21 of the enlarged head, the mixing head 31 of the lower enlarged head, the mixing head 41 of the mixing pile, and the drill bit 8, arranged in order from top to bottom, are lifted above the ground, and the power supply to the winch mechanism 14, the second power head 6, and the first power head 5 is turned off.

[0106] The walking mechanism 11 is moved laterally and steps 1)-4) are repeated. After the construction of one row with upper enlarged head 71, lower enlarged head 73 and mixing pile 75 is completed, the walking mechanism 11 is moved longitudinally backward and steps 1)-4) are repeated to construct the second row with upper enlarged head 71, lower enlarged head 73 and mixing pile 75. Then the construction is carried out row by row until the upper enlarged head 71, lower enlarged head 73 and mixing pile 75 are installed, and the reinforcement treatment of the soft soil foundation for anti-settlement is completed piece by piece.

[0107] It is easy to understand that the mixing pile 75 with the enlarged head 71 is also called the mixing pile 75 equipped with the enlarged head 71. The pile driver 1 can also be called a drilling rig, a mixing drilling rig, or a mixing drilling equipment. The lower enlarged head 31, from the perspective of its position in the entire mixing pile, can also be called the middle enlarged head. The pile driver 1 may also include a control device in the operating room 15. The cylinder of the traveling mechanism 11, the winch of the hoisting mechanism 14, the first inner drill rod motor 52, the first outer drill rod motor 56, the second inner drill rod motor 62, and the second outer drill rod motor 66 are all electrically connected to and driven by the control device, such as a main controller or computer. The power head housing is also called the power head outer shell. Both the inner and outer drill rods are made of steel pipes, and the grout delivery pipe can be made of plastic pipes. The reinforcement treatment for soft soil foundation settlement prevention is also called the solidification treatment for soft soil foundation settlement prevention. The vertical plate is also called the vertical plate. Multiple pieces are also called multiple blocks. Multiple pieces include two pieces and more. The frame leaf is also called the frame leaf. Multiple sections include two or more sections, such as two, three, or four sections. A gearbox is also called a transmission, reduction gearbox, or reducer. Coaxial fixing means coaxial axis fixing. An enlarged head is also called a mixing pile enlarged head. A frustum transition section is also called a frustum conical transition section, a conical transition section, a frustum transition surface, or a frustum-shaped transition surface. The frustum transition section 72 can be a smooth frustum transition section or a frustum stepped transition section 78 with multiple steps 781; of course, a smooth frustum transition section is preferred. A smooth frustum transition section is composed of straight inclined plates, while a frustum stepped transition surface is composed of inclined step plates 100 with multiple steps on the outer side.

[0108] Components, structures, or quantities not marked above are not shown in the drawings, and some components are not marked in the drawings. The drawings are for illustrative purposes only. In case of any inconsistency between the drawings and the text description, or between the drawings themselves, the text description shall prevail.

[0109] The above description is merely a preferred embodiment of this utility model and is not intended to limit the utility model. Various modifications and variations can be made to this utility model by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this utility model should be included within the protection scope of this utility model.

Claims

1. A combined bidirectional stirring device, characterized in that: The upper end of the first upper outer drill rod is connected to the first power head, and the lower end of the first upper outer drill rod is fixed to the upper end of the first stirring frame of the stirring head of the upper enlarged head. The upper end of the first lower outer drill rod is fixed to the lower end of the first stirring frame of the stirring head of the upper enlarged head, and the lower end of the first lower outer drill rod is fixed to the upper end of the second stirring frame of the stirring head of the lower enlarged head. The first upper outer drill pipe is coaxial with the first lower outer drill pipe; The first inner drill rod is rotatably fitted inside the first upper outer drill rod and the first lower outer drill rod. The upper end of the first inner drill rod is connected to the first power head, and the lower end of the first inner drill rod is rotatably fitted to the first lower connecting sleeve of the second stirring frame of the lower enlarged head. Above the first power head is a second power head. The upper end of the second outer drill rod is connected to the second power head. The first power head has a passage for the second outer drill rod to pass through. The second outer drill rod is slidably engaged with the first inner drill rod. The second inner drill rod is rotatably engaged with the second outer drill rod. The upper end of the second inner drill rod is connected to the second power head. The lower end of the second outer drill rod is fixed to the upper end of the third mixing frame of the mixing head of the mixing pile, and the lower end of the second inner drill rod is rotatably engaged with the second lower connecting sleeve of the third mixing frame of the mixing pile. The drill bit is located at the bottom end of the second inner drill rod below the mixing head of the mixing pile.

2. The combined bidirectional stirring device according to claim 1, characterized in that: The stirring head of the upper enlarged head includes a first stirring frame and a first inner drill rod located in the stirring head section of the upper enlarged head. Multiple first outer stirring blades are fixed on the first stirring frame, and multiple first inner stirring blades are fixed on the first inner drill rod located in the stirring head section of the upper enlarged head. The first inner stirring blades and the first outer stirring blades are staggered in height and stir each other in opposite directions. The stirring head of the lower enlarged head includes a second stirring frame and a first inner drill rod located in the stirring head section of the lower enlarged head. Multiple second outer stirring blades are fixed on the second stirring frame, and multiple second inner stirring blades are fixed on the first inner drill rod located in the stirring head section of the lower enlarged head. The second inner stirring blades and the second outer stirring blades are staggered in height and stir each other in opposite directions. The mixing head of the mixing pile includes a third mixing frame and a second inner drill rod located in the mixing head section of the mixing pile. Multiple third outer mixing blades are fixed on the third mixing frame, and multiple third inner mixing blades are fixed on the second inner drill rod located in the mixing head section of the mixing pile. The third inner mixing blades and the third outer mixing blades are staggered in height and stir each other in opposite directions.

3. The combined bidirectional intermixing device of claim 2, wherein: Multiple first frame pages constitute the first stirring frame of the stirring head of the enlarged head: the multiple first frame pages are distributed along the circumference, the inner end of the first upper horizontal plate of each first frame page is fixed to the lower end of the first upper outer drill rod, the outer end of the first upper horizontal plate is fixed to the upper end of the first vertical plate, the lower end of the first vertical plate is fixed to the upper end of the first inclined plate, and the lower end of the first inclined plate is fixed to the upper end of the first lower outer drill rod.

4. The combined bidirectional intermixing device of claim 2, wherein: Multiple second frame panels constitute the second stirring frame of the stirring head of the lower enlarged head: the multiple second frame panels are distributed along the circumference; the inner end of the second upper horizontal plate of each second frame panel is fixed to the lower end of the second outer drill rod, the outer end of the second upper horizontal plate is fixed to the upper end of the second vertical plate, the lower end of the second vertical plate is fixed to the upper end of the second inclined plate, the lower end of the second inclined plate is fixed to the first lower connecting sleeve, and the first lower connecting sleeve is rotatably engaged with the lower end of the first inner drill rod.

5. The combined bidirectional intermixing device of claim 2, wherein: Multiple third frame panels constitute the third mixing frame of the mixing head of the mixing pile: multiple third frame panels are distributed along the circumference; the inner end of the third upper horizontal plate of each third frame panel is fixed to the lower end of the second outer drill rod, the outer end of the third upper horizontal plate is fixed to the upper end of the third vertical plate, the lower end of the third vertical plate is fixed to the outer end of the third lower horizontal plate, the inner end of the third lower horizontal plate is fixed to the second lower connecting sleeve, and the second lower connecting sleeve is rotatably engaged with the lower end of the second inner drill rod.

6. A mixing pile with an enlarged head, characterized in that: The aforementioned mixing pile with enlarged head is formed by mixing the pile using the combined bidirectional mixing device described in any one of claims 1-5; the top is an upper enlarged head, the bottom of the upper enlarged head is a lower enlarged head, the bottom of the lower enlarged head is a mixing pile, and there are frustum transition sections between the upper and lower enlarged heads and between the lower enlarged head and the mixing pile, thus forming a mixing pile with double enlarged heads and frustum transition sections; there are multiple rows of mixing piles with enlarged heads and frustum transition sections, with multiple piles in each row; the upper enlarged heads of adjacent rows are staggered; there are gaps between adjacent upper enlarged heads, or adjacent upper enlarged heads are tangent to each other, or adjacent upper enlarged heads are interlocked.

7. The mixing pile with enlarged head according to claim 6, characterized in that: The staggered arrangement refers to the fact that the diameter line of a circle of each enlarged head in a row is perpendicular to the line connecting the centers of two adjacent enlarged heads in an adjacent row, and the diameter line of this circle bisects the line connecting the centers.

8. The mixing pile with enlarged head according to claim 6, characterized in that: The gap between adjacent enlarged heads is 1mm-50mm.

9. The mixing pile with enlarged head according to claim 6, characterized in that: The aforementioned frustum transition section is either a smooth frustum transition section or a stepped frustum transition section.

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