A short helix drill bit for a mixing pile and a combined drill tool with the short helix drill bit

Abstract

The present invention relates to the technical field of underground construction machinery and equipment, and a short helix drill bit for mixing piles and a combined drill tool with the short helix drill bit. The combined drill tool includes a top joint, a central shaft, a frame structure, and the above-mentioned short helix drill bit. The top joint is connected to the central shaft. The central shaft sequentially includes an outer tube, an inner tube, and a central tube from outside to inside, and multiple material conveying channels are formed between the three tubes. The frame structure is connected to the central shaft in a single-layer or double-layer manner, and multiple layers of transverse stirring vanes are provided. The top of the short helix drill bit is connected to the bottom end of the central shaft. The short helix drill bit includes a drill bit main rod, a first injection port, short helix blades, and a drill tip. The inner and outer tubes of the combined drill tool can rotate in opposite directions under the clockwise and counterclockwise torques of the double power heads, and can achieve the staggered shear stirring of adjacent transverse stirring vanes, as well as the spiral self-tapping drilling of the short helix drill bit and the compaction enhancement effect of the backpressure technology.

Description

Technical Field

[0001] The present invention relates to the technical field of underground construction machinery and equipment, and in particular to a short helix drill bit for mixing piles and a combined drill tool with the short helix drill bit. Background Art

[0002] After the deep mixing pile technology based on unidirectional rotation mixing was introduced into China from Europe and Japan, it began to be widely used in the field of civil engineering in the mid-late 20th century. The deep mixing pile engineering technology uses a single-axis or multi-axis mixing drill rig to input solidifying materials such as cement into the ground. By mixing with the soil, a series of physical and chemical reactions occur between the solidifying materials and the soil, generating piles, walls, and blocks with high strength, good water stability, and strong anti-seepage performance. Thus, it effectively solves the practical engineering problems such as the bearing capacity of composite foundations, mixing pile bearing capacity, stiff core composite pile bearing capacity, SMW method pile bearing capacity, anti-seepage force of cut-off walls, and the sealing partitions and sealing layers of contaminated soil and toxic substance landfills.

[0003] In the existing deep mixing pile engineering technology, when using the existing construction drill bits and techniques of unidirectional rotation mixing and bidirectional mixing, it is usually impossible to drill and mix relatively hard fully weathered, strongly weathered, dense sandy soil, and hard plastic clay strata. When using the existing construction drill bits and techniques of unidirectional rotation mixing, the soil is often unevenly mixed, and problems of paste drilling and sticking drilling are likely to occur during construction in cohesive soil, and the overall strength of the solidified soil is low, which are engineering quality and safety problems. Summary of the Invention

[0004] The present invention aims to solve the problems that the existing construction drill bits and techniques of unidirectional rotation mixing and bidirectional mixing cannot drill and mix relatively hard fully weathered, strongly weathered, dense sandy soil, and hard plastic clay strata, as well as the technical problems of uneven soil mixing, easy occurrence of paste drilling and sticking drilling during construction in cohesive soil, and low overall strength of the solidified soil. The present invention provides a short helix drill bit and a combined drill tool that enhance the drilling and mixing ability, improve the mixing effect, and are suitable for construction of hard soil foundations and large-diameter and large-depth mixing piles.

[0005] To achieve the purpose of the present invention, the following technical solutions are adopted:

[0006] A short helix drill bit for mixing piles, comprising a drill bit main rod, a first injection port, short helix blades and a drill tip; an injection channel for injecting materials is arranged inside the drill bit main rod; the first injection port is arranged at the bottom of the drill bit main rod, and the first injection port is communicated with the discharge end of the injection channel; the short helix blades are arranged on the outer wall of the drill bit main rod; a plurality of spaced plate teeth are arranged at the upper end of the short helix blades; a plurality of spaced cut teeth are arranged at the lower end of the short helix blades; the drill tip is connected to the bottom of the drill bit main rod. The application of the short helix drill bit can drill and mix relatively hard fully weathered, strongly weathered, dense sandy soil and hard plastic clay strata; the powerful self-drilling ability of the helix drill can solve the technical problems that traditional single-direction mixing tools and existing two-direction mixing tools cannot implement the construction of mixing piles with large diameters and large depths in hard soil strata.

[0007] Preferably, the rotation expansion angle range of the short helix blades is 0° to 1800°, forming one to five circles of continuous helix blades; the diameter of the continuous helix blades is of equal diameter or variable diameter, and the pitch of the continuous helix blades is of equal pitch or unequal pitch. Different drilling and mixing effects can be achieved by changing different forms.

[0008] Preferably, a plurality of spaced shear plates are arranged between adjacent upper and lower continuous helix blades in the short helix blades. The soil cutting and mixing ability can be further improved by the shear plates.

[0009] Preferably, the short helix blades are composed of a plurality of discontinuous helix blades; the plurality of discontinuous helix blades are longitudinally spaced on the outer wall of the drill bit main rod; the plurality of cut teeth are arranged at the bottom end of the discontinuous helix blade at the bottom. The use of discontinuous and segmented discontinuous helix blades is convenient for further improving the mixing ability and the soil breaking ability.

[0010] Preferably, the plate teeth are arranged at the arc-shaped termination edge at the top of the short helix blades, and the angle of the plate teeth is similar to the angle of the arc-shaped termination edge at the top of the short helix blades; the cut teeth are arranged at the arc-shaped starting edge at the bottom of the short helix blades, and the angle of the cut teeth is 15° to 35°. The mixing ability and the soil breaking ability can be further improved by the plate teeth and the cut teeth.

[0011] Preferably, a first wear-resistant plate is welded to the outer edge of the short helix blades; the drill tip is integrally in a cross-shaped structure, and a plurality of drill tip teeth are arranged at the bottom of each branch rod of the cross-shaped drill tip. The use of the first wear-resistant plate can extend the service life of the short helix blades and improve the soil breaking ability of the drill tip.

[0012] Preferably, a combined drill for mixing piles comprises, from top to bottom, a top joint, a central shaft, a frame structure and the short helix drill bit of the mixing pile as described above. The top joint is located at the top of the central shaft. The central shaft comprises, from outside to inside, an outer pipe, an inner pipe and a central pipe, and multiple material conveying channels are formed between the three pipes. The frame structure is connected to the outer peripheral wall of the central shaft. The top of the short helix drill bit is connected to the bottom of the central shaft. The outer pipe and the inner pipe of the combined drill can rotate in opposite directions under the clockwise and counterclockwise torques of the double power heads, achieving the spiral self-attack drilling of the short helix drill bit and the compaction enhancement effect of the backpressure technology.

[0013] Preferably, the frame structure is a single-layer frame structure. The upper end of the frame structure is fixedly connected to the outer side wall of the outer pipe of the central shaft through a first fixed ring sleeve. The lower end of the frame structure is rotatably connected to the outer side wall of the inner pipe of the central shaft through a first annular limit support bearing sleeve, and the frame structure can follow the rotation of the outer pipe of the central shaft. The top joint is located at the top of the central shaft. The top joint is a female joint structure. The top joint is connected to the bottom end of the upper inner and outer active drill pipes. The structures of the inner and outer active drill pipes are the same as that of the central shaft, and male joints are provided at the bottom ends of the inner and outer active drill pipes. The top joint is fixedly and hermetically connected to the male joint and bears the axial force through a locking pin bearing. The single-layer frame structure is divided into multiple single-layer frames in an evenly divided manner. The single-layer frames are connected to the outer peripheral wall of the central shaft. Multiple first transverse mixing wing plates are provided on the inner side wall of the vertical outer edge plate of the single-layer frame, and multiple second transverse mixing wing plates are also fixedly connected to the outer peripheral wall of the central shaft. The first transverse mixing wing plates and the second transverse mixing wing plates are arranged at intervals. Multiple upwardly spaced and vertically upward upper tooth plates are installed on the upper end face of the top of the single-layer frame, and multiple downwardly spaced and vertically downward lower tooth plates are installed on the lower end face of the bottom of the single-layer frame. When the upper frame structure system and the lower short helix drill bit rotate, they do not affect each other and can rotate independently in the same or opposite directions. Since the rotation directions of adjacent transverse mixing wing plates in the upper frame structure system are opposite, the soil to be reinforced can be fully and evenly sheared and strongly mixed with each other.

[0014] Preferably, the frame structure is a double-layer frame structure, which includes an outer frame and an inner frame; the upper end of the outer frame is fixedly connected to the outer side wall of the outer tube of the central shaft through a second fixed ring sleeve; the lower end of the outer frame is rotationally connected to the outer side wall of the inner tube of the central shaft through a second annular limiting support bearing bushing, and the outer frame can rotate following the outer tube of the central shaft; the upper end of the inner frame is rotationally connected to the outer side wall of the outer tube of the central shaft through a third annular limiting support bearing bushing, and the lower end of the inner frame is fixedly connected to the outer side wall of the inner tube of the central shaft through a third fixed ring sleeve, and the inner frame can rotate following the inner tube of the central shaft; multiple transverse T-shaped stirring vanes are also fixedly connected to the outer peripheral wall of the central shaft; a fourth transverse stirring vane is arranged inside the inner frame at intervals with the multiple transverse T-shaped stirring vanes; multiple fifth transverse stirring vanes are arranged outside the inner frame; vertical stirring vanes are also arranged on the upper and lower outer sides of the inner frame; a sixth transverse stirring vane is arranged inside the outer frame at intervals with the multiple fifth transverse stirring vanes. When the outer frame, inner frame and the short spiral drill bit at the bottom end of the double-layer frame structure rotate, they do not affect each other and can all rotate independently in the same or opposite directions, and the rotation directions of adjacent transverse stirring vanes in the double-layer frame structure system are opposite to each other.

[0015] Preferably, the combined drill also includes a second injection port and a third injection port; the second injection port communicates with the annular gap between the inner tube and the central tube and is arranged at the side rear part of the lower end of the outer frame, and the third injection port communicates with the annular gap between the inner tube and the outer tube and is arranged on the outer wall of the vertical outer edge plate of the outer frame; a second wear-resistant plate is welded to the outer edge of the frame structure; a dynamic seal and an oil injection hole for lubricating oil are arranged on the annular limiting support bearing bushing of the frame structure. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 is the first structural schematic diagram of the short spiral drill bit of the present invention.

[0017] Figure 2 is the second structural schematic diagram of the short spiral drill bit of the present invention.

[0018] Figure 3 is the third structural schematic diagram of the short spiral drill bit of the present invention.

[0019] Figure 4 is the fourth structural schematic diagram of the short spiral drill bit of the present invention.

[0020] Figure 5 is the structural schematic diagram of the first combined drill of the present invention.

[0021] Figure 6 is the structural schematic diagram of the second combined drill of the present invention.

[0022] Figure 7It is a schematic structural view of the third combined drill tool of the present invention.

[0023] Figure 8 It is a schematic structural view of the two-piece single-layer frame structure of the present invention.

[0024] Figure 9 It is a schematic structural view of the three-piece single-layer frame structure of the present invention.

[0025] Figure 10 It is a schematic structural view of the four-piece single-layer frame structure of the present invention.

[0026] Figure 11 It is a schematic structural view of the two-piece double-layer frame structure of the present invention.

[0027] Figure 12 It is a schematic structural view of the three-piece double-layer frame structure of the present invention.

[0028] Figure 13 It is a schematic structural view of the four-piece double-layer frame structure of the present invention.

[0029] Figure 14 It is a schematic view of the injection structure in the first combined drill tool of the present invention.

[0030] Figure 15 It is a schematic view of the injection structure in the second combined drill tool of the present invention.

[0031] Figure 16 It is a schematic view of the injection structure in the third combined drill tool of the present invention.

[0032] Figure 17 It is a schematic structural view of a kind of transverse stirring vane of the present invention.

[0033] Figure 18 It is another schematic structural view of the transverse stirring vane of the present invention.

[0034] Figure 19 It is a schematic view of the central shaft structure of the present invention.

[0035] Figure 20 It is a schematic structural view of the male joint of the present invention.

[0036] Figure 21 It is a cross-sectional view of the top joint of the present invention.

[0037] Figure 22 It is a side view of the drill tip structure of the present invention.

[0038] Figure 23 It is a bottom view of the drill tip structure of the present invention.

[0039] Figure 24It is a schematic structural diagram of the overall use process of the present invention.

[0040] Among them: 1 - combined drill tool, 2 - frame structure, 3 - central shaft, 4 - material conveying channel, 5 - top joint, 6 - short helix drill bit, 7 - outer pipe, 8 - inner pipe, 9 - central pipe, 10 - inner and outer active drill pipes, 11 - male joint, 12 - female joint structure, 13 - double power head, 23 - single-layer frame, 24 - vertical outer plate, 25-1 - first transverse stirring wing plate, 25-2 - second transverse stirring wing plate, 25-3 - transverse T-shaped stirring wing plate, 25-4 - fourth transverse stirring wing plate, 25-5 - fifth transverse stirring wing plate, 25-6 - sixth transverse stirring wing plate, 26 - lower tooth plate, 27 - upper tooth plate, 28 - outer frame, 29 - inner frame, 291 - vertical stirring wing plate, 31 - first fixed collar, 32 - first annular limiting support bearing bushing, 35 - locking pin, 401 - first material conveying channel, 402 - second material conveying channel, 403 - third material conveying channel, 41 - second fixed collar, 42 - second annular limiting support bearing bushing, 43 - third annular limiting support bearing bushing, 44 - third fixed collar, 52 - second injection port, 53 - third injection port, 55 - oil injection hole, 56 - second wear-resistant plate, 600 - injection channel, 601 - drill bit main rod, 602 - first injection port, 603 - short helix blade, 604 - drill tip; 605 - plate tooth; 606 - pick, 607 - shear plate, 608 - discontinuous helix blade, 609 - drill tip tooth, 610 - first wear-resistant plate, 61 - two-way stirring mechanism, 62 - swivel, 63 - integrated suspension device, 64 - external material supply pipeline, 65 - background slurry supply system. Specific embodiments

[0041] To make the above objects, features, and advantages of the present invention more obvious and understandable, the following detailed description of the specific embodiments of the present invention will be given with reference to the accompanying drawings.

[0042] Embodiment 1

[0043] As Figure 1 and Figure 14As shown, a short auger bit 6 for mixing piles includes a bit main rod 601, a first injection port 602, short auger blades 603, and a drill tip 604; an injection channel 600 for injecting a curing agent, water, gas, or other materials is provided inside the bit main rod 601; the first injection port 602 is provided on one side of the lower part of the bit main rod 601, and the first injection port 602 is communicated with the discharge end of the injection channel 600. The first injection port 602 is a single circular hole, oval hole, rectangular hole, or multiple circular holes or slit-shaped long holes, and the curing agent is ejected from the first injection port 602 through the injection channel 600. During the drilling and mixing process, the soil and the curing agent are evenly mixed and fully blended, which can save a large amount of curing agent materials. At the same time, it can ensure excellent quality, shortened construction period, and reduced cost of the deep mixing pile. The short auger blades 603 are arranged on the outer wall of the bit main rod 601. Through the short auger blades 603, it is possible to drill and mix relatively hard completely weathered, strongly weathered soil, dense sand, or hard plastic clay soil. And when using the controlled-speed reverse rotation and lifting mixing process, through the backpressure technology of the short auger blades 603, the further compaction and strengthening effect of the solidified soil can be achieved, improving the compactness and strength of the solidified soil. The rotation expansion angle range of the short auger blades 603 is 0° to 720°, forming two circles of continuous auger blades; the diameter of the continuous auger blades is of equal diameter type, and the pitch of the continuous auger blades is of equal pitch type. The diameter of the continuous auger blades is 1100 mm, and the pitch is 200 mm; between the upper and lower adjacent continuous auger blades in the short auger blades 603, multiple shear plates 607 arranged at intervals are provided. The cross-sectional shape of the shear plate 607 is preferably a rhombus, and the cross-section of the shear plate 607 can also adopt other shapes. Through the shear plate 607, the soil can be effectively cut to improve the mixing uniformity and mixing effect. At the upper end of the short auger blades 603, multiple plate teeth 605 arranged at intervals are provided; the plate teeth 605 are arranged on the arc-shaped termination edge at the top of the short auger blades 603, and the angle of the plate teeth 605 is close to the angle of the arc-shaped termination edge at the top of the short auger blades 603; at the lower end of the short auger blades 603, multiple cut teeth 606 arranged at intervals are provided; the cut teeth 606 are arranged on the arc-shaped starting edge at the bottom of the short auger blades 603, and the angle of the cut teeth 606 is 26°. Both the plate teeth 605 and the cut teeth 606 are made of alloy materials, which can further extend the service life of the auger blades and improve the drilling and mixing ability of the short auger bit 6. A first wear-resistant plate 610 is welded to the outer edge of the short auger blades 603. By adding a layer of protection to the short auger blades 603 through the first wear-resistant plate 610, the loss of the short auger blades 603 can be reduced, thereby further improving the service life of the short auger blades 603. As Figure 22 and Figure 23As shown, the drill tip 604 is connected to the bottom of the drill bit main rod 601. The drill tip 604 is integrally in a cross-shaped structure, and multiple drill tip teeth 609 are provided at the bottom of each branch rod of the cross-shaped drill tip 604 to enhance the soil-breaking ability of the drill tip 604.

[0044] The short helix drill bit 6 can drill and agitate relatively hard completely weathered, strongly weathered soil bodies, dense sandy soil or hard plastic clay bodies, and improve the soil agitation uniformity and the overall strength of the solidified soil.

[0045] Embodiment 2

[0046] There are differences in the short helix blades 603 and the pick teeth 606 between Embodiment 2 and Embodiment 1, and other structures are the same.

[0047] As Figure 2 shown, the rotation expansion angle range of the short helix blade 603 is 0° to 900°, forming 2.5 turns of continuous helix blades; the diameter of the continuous helix blades is of equal diameter type, and the pitch of the continuous helix blades is of equal pitch type. The diameter of the continuous helix blades is 2000 mm and the pitch is 260 mm. The angle of the pick teeth 606 is 28°. This structure can further improve the drilling and agitation effect in medium-hard soil layers by increasing the number of turns of the short helix blade 603.

[0048] Embodiment 3

[0049] There are differences in the short helix blades 603 and the pick teeth 606 between Embodiment 3 and Embodiment 1, and other structures are the same.

[0050] As Figure 3 shown, the rotation expansion angle range of the short helix blade 603 is 0° to 900°, forming 2.5 turns of continuous helix blades; the diameter of the continuous helix blades is of variable diameter type, and the diameter gradually decreases from top to bottom. By gradually reducing the diameter of the helix blade, the drilling and agitation ability and the soil-breaking ability of the short helix drill bit can be further improved, so as to cope with harder soil layers, and at the same time, it is also convenient for subsequent agitation operations. The plate teeth 605 at the top of the short helix blade 603 are made of conventional alloy materials, while the pick teeth 606 at the bottom of the short helix blade 603 are made of high-strength and high-hardness alloy materials. This structure is specifically for relatively hard soil layers that are difficult to drill and agitate, and multiple shear plates 607 arranged at intervals can also be provided between adjacent continuous helix blades above and below to enhance the ability to shear the soil.

[0051] Embodiment 4

[0052] There are differences in the short helix blades 603 between Embodiment 4 and Embodiment 1, and other structures are the same.

[0053] As Figure 4As shown, the short helical blade 603 is composed of three discontinuous helical blades 608; the rotational expansion angle range of the discontinuous helical blade 608 at the bottom is 0° to 540°, forming a continuous helical blade of 1.5 turns, and the pitch of the discontinuous helical blade 608 at the bottom is 250 mm. The rotational expansion angles of the 2 discontinuous helical blades 608 above start from 540°, with a 180° non-helical blade area and a 540° helical blade area arranged at intervals. The three discontinuous helical blades 608 are of equal diameter, and the diameter of the discontinuous helical blade 608 is 1800 mm. The discontinuous helical blades 608 are longitudinally arranged at intervals on the outer wall of the drill bit main rod 601; the top end of the discontinuous helical blade 608 at the top can be selectively provided with plate teeth 605. A plurality of the pick teeth 606 are arranged at the bottom end of the discontinuous helical blade 608 at the bottom. The use of discontinuous and segmented discontinuous helical blades 608 can further improve the mixing ability and soil breaking ability of the short helical drill in special complex soil layers.

[0054] Example 5

[0055] As Figure 5 and Figure 14 shown, a combined drill tool 1 with a short helical drill bit includes, from top to bottom, a top joint 5, a central shaft 3, a frame structure 2, and the above-mentioned short helical drill bit 6 in sequence; the top joint 5 is located at the top end of the central shaft 3; the central shaft 3 includes an outer tube 7, an inner tube 8, and a central tube 9 from outside to inside in sequence, and multiple material conveying channels 4 are formed between the three tubes; as Figure 19 shown, the material conveying channels 4 are respectively the first material conveying channel 401 inside the central tube 9, the second material conveying channel 402 between the outer wall of the central tube 9 and the inner wall of the inner tube 8, and the third material conveying channel 403 between the outer wall of the inner tube 8 and the inner wall of the outer tube 7. The frame structure 2 is connected to the outer peripheral wall of the central shaft 3; the top end of the short helical drill bit 6 is connected to the bottom end of the central shaft 3. The outer tube and the inner tube of the combined drill tool can rotate in opposite directions under the clockwise and counterclockwise torques of the double power heads; respectively realizing the helical self-tapping drilling of the short helical drill bit 6 and the compaction enhancement effect of the reverse pressure technology.

[0056] By introducing a combined drill tool driven by a dual power head, the pile driver can construct mixing piles with a diameter less than 3000 mm and can achieve the construction of deep mixing piles in complex and hard soil layers. The main advantage of this new type of drill tool is that under the forward and reverse torque and drilling pressure of the dual power head, the short helix drill bit 6 of the mixing pile combined drill tool can utilize its spiral self-tapping performance to achieve drilling and mixing construction in fully weathered, strongly weathered, dense sandy soil and hard plastic clay layers during the downward operation stage; during the upward reverse rotation operation stage of the short helix drill bit 6, the speed-controlled rotation lifting and mixing process and the backpressure technology can also promote the compaction and strengthening effect of the short helix blade 603 on the solidified soil, thereby improving the compactness and strength of the solidified soil; during construction, the combined drill tool 1 can rotate bidirectionally at the same speed or at variable speeds. Since the rotation directions of the adjacent frames and the transverse mixing wing plates of the drill tool are opposite, by using the bidirectional mixing and mutual shearing functions of each frame and the adjacent transverse mixing wing plates, the technical problems of the upward discharge of the solidified soil along the circumferential gap between the drill tool and the drill pipe during the construction of traditional mixing drill tools and the stubborn problem of the drill tool being stuck in a mass in the viscous soil layer can be solved, and it promotes the mutual shearing, rubbing and crushing, and strong mixing of the solidified soil mass being stirred, as well as the uniformity and high strength of the mixing pile body.

[0057] As Figure 5 and Figure 14 shown, the frame structure 2 is a single-layer frame structure. The upper end of the frame structure 2 is fixedly connected to the outer side wall of the outer pipe 7 of the central shaft 3 through the first fixed ring sleeve 31. The lower end of the frame structure 2 is rotatably connected to the outer side wall of the inner pipe 8 of the central shaft 3 through the first annular limit support bearing sleeve 32, and the frame structure 2 can follow the rotation of the outer pipe 7 of the central shaft 3.

[0058] As Figure 20 and Figure 21 shown, the top joint 5 is located at the top of the central shaft 3; a female joint structure 12 in the shape of an internal hexagon is provided on the top joint 5; the top joint 5 is hermetically connected to the lower end of the inner and outer active drill pipes 10; the structure of the inner and outer active drill pipes 10 is the same as that of the central shaft 3, and a male joint 11 in the shape of an external hexagon is provided at the bottom end of the inner and outer active drill pipes 10; the female joint structure 12 is fixedly and hermetically connected to the male joint 11, and the inner and outer hexagons transmit torque and bear axial force through the locking pin shaft 35.

[0059] On the outer peripheral side of the outer pipe 7 of the central shaft 3 of the single-layer frame structure, three single-layer frames 23 of the same size are radially installed in an equally divided manner at 120°; the single-layer frames 23 are connected to the outer peripheral wall of the central shaft 3; as Figures 8 - 10 shown, it can also be two single-layer frames 23 of the same size or four single-layer frames 23 of the same size. The outer edge of the single-layer frame 23 is welded with a second wear-resistant plate 56. The frame structure is further protected through the second wear-resistant plate 56, and the service life of the frame structure is improved.

[0060] On the inner side wall of the vertical outer edge plate 24 of the single-layer frame 23, there are multiple first transverse stirring wing plates 25-1 arranged, and on the outer peripheral wall of the central axis 3, there are also fixedly connected multiple second transverse stirring wing plates 25-2; the first transverse stirring wing plates 25-1 and the second transverse stirring wing plates 25-2 are arranged at intervals; as Figure 18 shown, the cross-sections of both the first transverse stirring wing plates 25-1 and the second transverse stirring wing plates 25-2 are trapezoidal. On the upper end surface of the top of the single-layer frame 23, there are multiple upper tooth plates 27 arranged at intervals and vertically upward, and on the lower end surface of the bottom of the single-layer frame 23, there are multiple lower tooth plates 26 arranged at intervals and vertically downward. Through the upper tooth plates 27 and the lower tooth plates 26, the stirring uniformity effect and the overall strength of the solidified soil can be further improved. By utilizing the two-way stirring and mutual shearing functions of each frame and the adjacent transverse stirring wing plates, the technical problems that the solidified soil is discharged upward along the gap between the drill and the drill pipe during the construction of traditional stirring drills and the stubborn problem of the drill being stuck in a mass in the construction of cohesive soil layers can be solved.

[0061] The structure of the short helix drill bit 6 is the same as that of the short helix drill bit 6 in Embodiment 1. The frame structure 2 in the upper part and the short helix drill bit 6 in the lower part of this combined stirring pile drill can rotate without affecting each other and can rotate independently in the same or opposite directions. Since the rotation directions of the adjacent transverse stirring wing plates in the upper frame structure 2 are opposite, the soil to be reinforced can be fully and evenly sheared and strongly mixed with each other.

[0062] Embodiment 6

[0063] The frame structure 2 and the short helix drill bit 6 in Embodiment 6 are different from those in Embodiment 5, and the other structures are the same.

[0064] As Figure 6 and Figure 15 shown, the frame structure 2 is a double-layer frame structure, and the frame structure 2 includes an outer frame 28 and an inner frame 29; on the outer peripheral side of the outer tube 7 of the central axis 3 of the double-layer frame structure, two sets of outer frames 28 and inner frames 29 of different sizes are radially installed in an average 180° division manner. As Figures 11 to 13 shown, it can also be two sets of outer frames 28 and inner frames 29 of different sizes with three sets each or two sets of outer frames 28 and inner frames 29 of different sizes with four sets each.

[0065] The upper end of the outer frame 28 is fixedly connected to the outer side wall of the outer tube 7 of the central shaft 3 through the second fixed collar 41; the lower end of the outer frame 28 is rotatably connected to the outer side wall of the inner tube 8 of the central shaft 3 through the second annular limiting support bearing bushing 42, and the outer frame 28 can follow the rotation of the outer tube 7 of the central shaft 3; the upper end of the inner frame 29 is rotatably connected to the outer side wall of the outer tube 7 of the central shaft 3 through the third annular limiting support bearing bushing 43, and the lower end of the inner frame 29 is fixedly connected to the outer side wall of the inner tube 8 of the central shaft 3 through the third fixed collar 44, and the inner frame 29 can follow the rotation of the inner tube 8 of the central shaft 3; multiple transverse T-shaped stirring vanes 25-3 are also fixedly connected to the outer peripheral wall of the central shaft 3; as Figure 17 shown, the side view of the transverse T-shaped stirring vane 25-3 is T-shaped; the T-shaped shape can increase the stirring area, and at the same time can further improve the stirring effect and the mutual shearing ability. A fourth transverse stirring vane 25-4 is arranged inside the inner frame 29 at intervals with the multiple transverse T-shaped stirring vanes 25-3; multiple fifth transverse stirring vanes 25-5 are arranged outside the inner frame 29; vertical stirring vanes 291 are also arranged on the upper and lower outer sides of the inner frame 29; a sixth transverse stirring vane 25-6 is arranged inside the outer frame 28 at intervals with the multiple fifth transverse stirring vanes 25-5. As Figure 18 shown, the cross-sections of the fourth transverse stirring vane 25-4, the fifth transverse stirring vane 25-5 and the sixth transverse stirring vane 25-6 are all trapezoidal. By using the double-direction stirring and mutual shearing functions of each frame and each adjacent transverse stirring vane, the technical problems of the cured soil discharging upward along the circumferential gap of the drill tool during the construction of the traditional stirring drill tool and the stubborn problem of the drill tool being stuck in a group during the construction in the cohesive soil layer can be solved.

[0066] The structure of the short helix drill bit 6 is the same as that of the short helix drill bit 6 in Embodiment 4.

[0067] As Figure 15 shown, the combined drill tool 1 further includes a second injection port 52; the second injection port 52 is a single circular hole, oval hole, rectangular hole, multiple circular holes or slit-shaped long holes. The second injection port 52 communicates with the annular gap between the inner tube 8 and the central tube 9, and is arranged at the side rear part of the lower end of the outer frame 28, realizing double-channel injection of the curing agent. Injecting the curing agent from different parts while the combined drill tool 1 is drilling and stirring can improve the overall uniformity and strength of the cured soil. Second wear-resistant plates 56 are welded to the outer edges of the outer frame 28 and the inner frame 29; the outer frame 28 and the inner frame 29 can be further protected through the second wear-resistant plates 56, and the service life of the frame structure can be extended. Oil injection holes 55 for dynamic seals and lubricating oil are arranged on the annular limiting support bearing bushings on the frame structure 2.

[0068] When the outer frame, inner frame of the double-layer frame structure 2 and the short helical drill bit 6 at the bottom rotate, they do not affect each other and can all rotate independently in the same or opposite directions. The rotation directions of adjacent transverse stirring vanes inside the double-layer frame structure 2 are opposite to each other.

[0069] Example 7

[0070] The double-layer frame structure 2 and the short helical drill bit 6 in Example 7 are different from the frame structure 2 and the short helical drill bit 6 in Example 5, and other structures are the same.

[0071] As Figure 7 and Figure 16 shown, the frame structure 2 is a double-layer frame structure. The frame structure 2 includes an outer frame 28 and an inner frame 29. The outer frames 28 and inner frames 29 of different sizes of three products are radially installed on the outer peripheral side of the outer tube 7 of the central axis 3 of the double-layer frame structure in a manner of being evenly divided at 120°. The structure of the short helical drill bit 6 is the same as that of the short helical drill bit 6 in Example 2.

[0072] As Figure 16 shown, the combined drill 1 further includes a third injection port 53. The third injection port 53 is a single circular hole, oval hole, rectangular hole, multiple circular holes or slit-shaped long holes. The third injection port 53 communicates with the annular gap between the inner tube 8 and the outer tube 7 and is arranged on the inner side of the vertical outer edge plate 24 of the outer frame 28. To achieve three-channel injection of the curing agent.

[0073] Example 8

[0074] As Figure 24 shown, a use process of a mixing pile combined drill. The combined drill 1 is assembled at the bottom of a two-way stirring mechanism 61 at the front end of a pile driver. The two-way stirring mechanism 61 that can be lifted and lowered is successively installed with a set of water faucets 62, double power heads 13, an integrally suspended device 63 that can move up and down, and independent inner and outer active drill pipes 10 from top to bottom. The central axis 3 is composed of triple pipes and has multiple material conveying channels 4. The curing agent can be conveyed to each injection port of the combined drill 1 through an external material supply pipeline 64, a water faucet 62, inner and outer active drill pipes 10, the central axis 3 and the short helical drill bit 6.

[0075] Specific process steps:

[0076] 1) Equipment assembly: After the dual-power head drill rig arrives at the site, the key point of assembly is to assemble the water faucet 62 of the two-way mixing mechanism 61, the dual-power head 13, the integrated suspension device 63, the inner and outer active drill pipes 10 and the combined drill tool 1 in sequence. The external material supply pipeline 64 is fixedly and hermetically connected to the water faucet 62. Using the integrated suspension device 63, the inner and outer active drill pipes 10 are fixedly and hermetically connected to the output end of the dual-power head 13 at the top. Finally, the top joint 5 of the combined drill tool 1 is fixedly and hermetically connected to the bottom end of the lowermost section of the inner and outer active drill pipes 10 to complete the assembly.

[0077] 2) Construction parameter setting: For the one-shot two-mixing construction process, set the construction torque, drilling pressure, rotation direction and rotation speed of the outer pipe 7 and the inner pipe 8, the drilling speed, the lifting speed of the drill rig at different depth sections, and the injection amount of the curing agent per meter of pile length at different depth sections. At the same time, start the curing agent mixing operation of the background mixing station, and fixedly and hermetically connect the input ends of the high-pressure grouting pump and the external material supply pipeline 64.

[0078] 3) Construction during the downward stage of the drill rig: After the drill rig is in place, start the drill rig and the background slurry supply system 65. Under the condition that the inner pipe 8 of the combined drill tool 1 and the short helix drill bit 6 rotate clockwise while the outer pipe 7 rotates counterclockwise, the drill rig applies positive and negative torques to the upper and lower power heads 13 respectively according to the set construction parameters for drilling and mixing operations during the downward stage. Among them, the short helix drill bit 6 uses the self-tapping characteristic of the helix to perform strong drilling operations at the bottom end of the drill tool. At the same time, use the high-pressure grouting pump to quantitatively distribute the curing agent through multiple injection ports. During the two-way mixing process of the combined drill tool 1, the soil to be reinforced can be fully and evenly mixed into solidified soil through mutual shearing and strong mixing. Until the downward operation of the two-way mixing mechanism 61 reaches the designed pile bottom elevation, the construction of the downward drilling and mixing operation stage is completed.

[0079] 4) Construction during the upward stage of the drill rig: Under the condition that the inner pipe 8 of the combined drill tool 1 and the short helix drill bit 6 rotate counterclockwise while the outer pipe 7 rotates clockwise, and on the technical premise that the lifting amount of the combined drill tool 1 per rotation of the short helix drill bit 6 is 0.5 pitches, the pile driver applies positive and negative torques and lifting forces to the upper and lower power heads 4 according to the set lifting speed and rotation speed of the combined drill tool 1, and uses the reverse extrusion technology to perform compaction and strengthening operations during the upward stage. During the secondary mixing operation, the combined drill tool 1 fully shears and strongly mixes the soil and the curing agent until the upward operation of the two-way mixing mechanism 61 reaches the designed pile top elevation, that is, the construction of the upward mixing operation stage is completed. End the construction operation of this mixing pile and move the pile driver.

[0080] Example 9

[0081] The following combines Figure 24 , Figure 1 ,Figure 5 , Figure 9 and Figure 14 The present invention will be further described. The engineering background of this embodiment is the cast-in-place concrete composite pile for the foundation pile of a small high-rise residential building under construction. The length of the mixing pile is 24m, the pile diameter is 1100mm, the length of the PHC pipe pile is 24m, the pile diameter is 700mm, and the design ultimate bearing capacity of a single pile is 4600kN.

[0082] The basic situation of this embodiment: The three-layer foundation soil of the site is respectively ① cohesive soil with a thickness of 12m, water content w = 36%, void ratio e = 1.35, SPT = 3 - 9; ② silt with a thickness of 9m, water content w = 27%, void ratio e = 1.1, SPT = 7 - 18; ③ completely weathered soil layer with a thickness of 19m, water content w = 25%, SPT = 13 - 29. The KD curing agent product is used, with an admixture amount of 12% and a water-cement ratio of 0.5. The single-channel spraying method is used for the spreading of the curing agent. The construction drill rig uses a double-power head drill rig driven by 2x12tm hydraulic pressure and a combined drill tool 1. The one-spray-two-agitation construction process of the mixing pile and the holding-pressure construction process of the PHC pipe pile are applied in the construction.

[0083] As Figure 5 , Figure 14 shown, a combined drill tool with a short helix drill bit includes, from top to bottom, a top joint 5, a central shaft 3, a material conveying channel 4, a frame structure 2, and a short helix drill bit 6. The frame structure 2 is connected to the short helix drill bit 6 by a quick connector. The central shaft 3 is composed of an outer pipe 7, an inner pipe 8, and a central pipe 9. The material conveying channel 4 is the first material conveying channel 401 inside the central pipe 9. The structure of the central shaft 3 is the same as that of the inner and outer active drill pipes 10. The outer pipe 7 and the inner pipe 8 of the combined drill tool 1 can rotate in opposite directions under the clockwise and counterclockwise torques of the double power heads 13.

[0084] As Figure 5 , Figure 9 shown, the frame structure 2 is a single-layer frame structure. Three single-layer frames 23 of the same size are radially installed on the outer peripheral side of the outer pipe 7 of the central shaft 3 of the single-layer frame structure at an average interval of 120°. Vertical outer edge plates 24 and first transverse stirring wing plates 25-1 are provided on the three branch brackets of the single-layer frame 23. A fixedly connected second transverse stirring wing plate 25-2 is installed on the outer peripheral side of the inner pipe 8 of the central shaft 3. A vertically downward lower tooth plate 26 is installed at the bottom of the lower end face of the single-layer frame 23, and a vertically upward upper tooth plate 27 is installed at the top of the upper end face. A short helix drill bit 6 with the same diameter as the mixing pile is installed at the bottom end of the central shaft 3. The single-layer frame 23 and the lower short helix drill bit 6 can rotate independently in the same or opposite directions. The rotation directions of the adjacent first transverse stirring wing plates 25-1 and the second transverse stirring wing plates 25-2 are opposite to each other, and the soil to be reinforced can be fully and evenly sheared and strongly mixed with each other.

[0085] The upper end of the single-layer frame 23 is fixedly connected to the first fixed ring sleeve 31 on the outer side wall of the outer tube 7 of the central shaft 3, and the lower end is rotatably connected to the outer side wall of the inner tube 8 of the central shaft 3 through the first annular limit support bearing bushing 32. Moreover, the single-layer frame structure can rotate following the outer tube 7 of the central shaft 3.

[0086] The short spiral blade 603 is designed with an equal diameter, and its rotation expansion angle range is 0° to 720°, and it can form 2 circles of continuous spiral blades; Shearing plates 607 with intervals are vertically arranged between the upper and lower continuous spiral blades; The diameter of the short spiral blade 603 is 1100 mm, and the pitch is 200 mm; At the bottom arc starting edge of the short spiral blade 603, picks 606 with an angle of 26° are installed, and at the top arc ending edge, plate teeth 605 are installed.

[0087] The first injection port 602 of the combined drill 1 uses a circular hole, which communicates with the first material delivery channel 401 in the central tube 9 and is arranged at the bottom of the short spiral drill bit 6; The second wear-resistant plate 56 is welded to the outer edge of the single-layer frame 23, and the first wear-resistant plate 610 is welded to the outer edge of the short spiral blade 603; Oil injection holes 55 for dynamic seals and lubricating oil are provided on each annular limit support bearing bushing of the single-layer frame 23.

[0088] The combined drill 1 is assembled at the bottom end of the two-way stirring mechanism 61 of the drill rig. The two-way stirring mechanism 61 that can be lifted and lowered is successively installed with a swivel 62, a dual power head 13, an integrated suspension device 63, and independent inner and outer active drill pipes 10 from top to bottom; The curing agent can be transported to the first injection port 602 through the external material supply pipeline 64, the swivel 62, the inner and outer active drill pipes 10, the central shaft 3, and the short spiral drill bit 6.

[0089] The usage process of the combined drill 1 in this embodiment is basically similar to that described in Embodiment 8, so the implementation process steps of this embodiment will not be repeated here.

[0090] Embodiment 10

[0091] The following combines Figure 24 、 Figure 4 、 Figure 11 、 Figure 8 、and Figure 15 to further elaborate on the present invention. The engineering background of this embodiment is the construction of a gravity cement-soil retaining wall for deep foundation pit support, adopting a double-row mixing pile design. The pile length is 31 m, the pile diameter is 1800 mm, and it is required that the unconfined compressive strength of the mixing pile at 28 days is not less than 0.9 MPa, and the permeability coefficient k is not greater than 10 -7 cm / s.

[0092] Basic situation of this embodiment: The foundation soil of the two-story site is ① clay with a layer thickness of 14 m, water content w = 42%, e = 1.2, SPT = 4 - 9, and ② silty sand with a layer thickness of 28 m, water content w = 27%, SPT = 13 - 28; 42.5 cement is used, with 3% bentonite added, the admixture amount is 15%, and the water-cement ratio is 1.0 - 1.6. The two-channel grouting method is used for the spread of the curing agent; The construction drill uses a 2x16tm electric-driven drill and a combined drill tool 1, and the one-spray-two-agitation construction process is applied.

[0093] As Figure 6 、 Figure 11 shown, the combined drill tool 1 driven by a dual-power head drill includes, from top to bottom, a top joint 5, a central shaft 3, a material conveying channel 4, a frame structure 2, and a discontinuous short helix drill bit 6. The upper frame structure 2 and the short helix drill bit 6 are connected by a quick joint; The central shaft 3 is composed of an outer pipe 7, an inner pipe 8, and a central pipe 9, and forms a dual-material conveying channel 4, as Figure 19 shown, which are the first material conveying channel 401 and the second material conveying channel 402 respectively. The structure of the central shaft 3 is the same as that of the inner and outer active drill pipes 10; The outer pipe 7 and the inner pipe 8 of the combined drill tool 1 rotate in opposite directions under the positive and negative torque of the dual-power head 13.

[0094] As Figure 6 、 Figure 11 shown, the frame structure 2 is a double-layer frame structure. On the outer peripheral side of the outer pipe 7 of the central shaft 3 of the double-layer frame structure, two sets of outer frames 28 and inner frames 29 of different sizes are radially installed in an average separation manner of 180 0 . Vertical outer edge plates 24 and transverse stirring wing plates are provided on the two sets of inner and outer frames. A fixed-connected transverse T-shaped stirring wing plate 25-3 is also installed on the outer peripheral side of the outer pipe 7 of the central shaft 3; A lower tooth plate 26 is installed at the bottom of the lower end face of the outer frame 28, and an upper tooth plate 27 is installed at the top of the upper end face; A short helix drill bit 6 with a diameter the same as that of the mixing pile is installed at the bottom end of the central shaft 3; When the outer frame 28, the inner frame 29, and the short helix drill bit 6 rotate, they do not affect each other and can rotate in the same or opposite directions. The rotation directions of the adjacent transverse stirring wing plates 25 in the frame structure 2 are opposite to each other.

[0095] The upper end of the outer frame 28 is fixedly connected to the second fixed ring sleeve 41 on the outer side wall of the outer pipe 7 of the central shaft 3. The lower end of the outer frame 28 is rotatably connected to the outer side wall of the inner pipe 8 of the central shaft 3 through a second annular limit support bearing bushing 42, and the outer frame 28 can rotate following the outer pipe 7 of the central shaft 3; The upper end of the inner frame 29 is rotatably connected to the outer side wall of the outer pipe 7 of the central shaft 3 through a third annular limit support bearing bushing 43, and its lower end is fixedly connected to the third fixed ring sleeve 44 on the outer side wall of the inner pipe 8 of the central shaft 3, and the inner frame 29 rotates following the inner pipe 8 of the central shaft 3.

[0096] The diameter of the short helical blade 603 of the short helical drill bit 6 is 1800 mm. The short helical blade 603 adopts three discontinuous helical blades. The rotational expansion angle of the continuous helical blade at the bottom is 0° to 540°, forming a continuous helical blade with 1.5 turns. The pitch of the continuous helical blade at the bottom of the short helical drill bit 6 is 250 mm, and a pick 606 with an angle of 30° is installed at the bottom arc starting edge of the short helical blade 603; the rotational expansion angles of the 2 discontinuous helical blades in the upper part start from 540°, and there are areas without helical blades spaced 180° and areas with helical blades of 540°.

[0097] The combined drill tool 1 is provided with 2 curing agent injection ports, namely the first injection port 602 and the second injection port 52. The first injection port 602 communicates with the first material delivery channel 401 in the central pipe 9 and is arranged at the bottom of the short helical drill bit 6. The second injection port 52 communicates with the second material delivery channel 402 between the inner pipe 8 of the central shaft 3 and the central pipe 9 and is arranged at the side rear part of the lower end of the outer frame. The second wear-resistant plates 56 are welded to the outer edges of each frame, and the first wear-resistant plates 610 are welded to the outer edges of the short helical blades 603; dynamic seals and oil injection holes 55 for lubricating oil are provided on the annular limiting support bearing bushings of each frame.

[0098] The combined drill tool 1 is assembled at the bottom end of the two-way stirring mechanism 61 of the drill rig. The two-way stirring mechanism 61 is successively installed with a double-channel water faucet 62, a double power head 13, an integrated suspension device 63, and inner and outer active drill pipes 10 from top to bottom; a double material delivery channel 4 is provided inside the central shaft 3, and the curing agent can be transported to each injection port through the external material supply pipeline 64, the water faucet 62, the inner and outer active drill pipes 10, the central shaft 3, and the short helical drill bit 6.

[0099] The usage process of the combined drill tool 1 in this embodiment is basically similar to that described in Embodiment 8, so the implementation process steps of this embodiment will not be repeated here.

[0100] Embodiment 11

[0101] The following combines Figure 24 、 Figure 2 、 Figure 7 、 Figure 12 and Figure 16 to further illustrate the present invention. The engineering background of this embodiment is the large-diameter mixing piles in the composite ground floor of the construction port container stacking yard. The pile length is 22 m, the pile diameter is 2000 mm, the design ultimate bearing capacity of the mixing pile composite foundation is 300 kPa, and the 28-day unconfined compressive strength of the mixing pile is not less than 1.0 MPa.

[0102] Basic situation of this embodiment: The site foundation soil is a deep marine saturated clay foundation with a water content of w = 61%, e = 1.32, q c = 0.2 MPa, f s = 6.5 kPa, SPT = 3 - 11. The surface soil of the site is a 2.8 m thick hard crust layer with a foundation bearing capacity of 120 kPa. The curing agent used is KD1 with an admixture amount of 15%. The powder + slurry injection method is used for injecting the curing agent dry powder and the curing agent slurry. The construction drill rig uses a 2x15tm electric-driven drill rig and a combined drill tool 1, and the construction adopts a one-spray-two-agitation construction process.

[0103] As Figure 7 、 Figure 12 shown, the combined drill tool 1 successively includes a top joint 5, a central shaft 3, a material delivery channel 4, a frame structure 2, and a short auger bit 6 from top to bottom. The upper frame structure 2 and the lower short auger bit 6 are connected by a quick joint. The central shaft 3 is composed of an outer tube 7, an inner tube 8, and a central tube 9, and three material delivery channels 4 are formed, as Figure 19 shown, namely the first material delivery channel 401, the second material delivery channel 402, and the third material delivery channel 403. The structure of the central shaft 3 is the same as that of the inner and outer active drill pipes 10. The outer tube 7 and the inner tube 8 of the combined drill tool 1 rotate in opposite directions under the positive and negative torques of the double power heads 13.

[0104] As Figure 7 、 Figure 12 shown, the frame structure 2 is a double-layer frame structure. The outer periphery of the outer tube 7 of the central shaft 3 of the double-layer frame structure is radially installed with three different-sized outer frames 28 and inner frames 29 at an average interval of 120°. Each of the three inner and outer frames is provided with a vertical outer edge plate 24 and a horizontal stirring wing plate. A fixed-connected horizontal T-shaped stirring wing plate 25-3 is also installed on the outer periphery of the outer tube 7 of the central shaft 3. The upper and lower end faces of the outer frame 28 are installed with a lower tooth plate 26 and an upper tooth plate 27. When the outer frame 28, the inner frame 29, and the short auger bit 6 rotate, they do not affect each other and can rotate in the same or opposite directions. The rotation directions of adjacent horizontal stirring wing plates in the upper double-layer frame structure 2 are opposite to each other.

[0105] The upper end of the outer frame 28 is fixedly connected to the second fixed ring sleeve 41 on the outer side wall of the outer tube 7 of the central shaft 3. The lower end of the outer frame 28 is rotatably connected to the outer side wall of the inner tube 8 of the central shaft 3 through a second annular limit support bearing bushing 42, and the outer frame 28 can rotate following the outer tube 7 of the central shaft 3. The upper end of the inner frame 29 is rotatably connected to the outer side wall of the outer tube 7 of the central shaft 3 through a third annular limit support bearing bushing 43, and its lower end is fixedly connected to the third fixed ring sleeve 44 on the outer side wall of the inner tube 8 of the central shaft 3, and the inner frame 29 rotates following the inner tube 8 of the central shaft 3.

[0106] The diameter of the short spiral blade 603 is 2000 mm, and the rotation expansion angle of the short spiral blade 603 is 0° to 900°, forming a continuous spiral blade with 2.5 turns. Shearing plates 607 with intervals are vertically arranged between the upper and lower continuous spiral blades; the pitch of the continuous spiral blade at the bottom of the short spiral drill bit 6 is 260 mm, and a pick 606 with an angle of 28° is installed at the bottom arc starting edge of the short spiral blade 603, and a plate tooth 605 is installed at the top arc ending edge; the second wear-resistant plates 56 are welded to the outer edges of each frame, and the first wear-resistant plate 610 is welded to the outer edge of the short spiral blade 603; dynamic seals and oil injection holes 55 for lubricating oil are provided on the annular limit support bearing bushings of each frame.

[0107] The combined drill 1 is provided with 3 curing agent injection ports, namely the first injection port 602, the second injection port 52 and the third injection port 53. The first injection port 602 communicates with the first material conveying channel 401 in the central pipe 9 and is arranged at the side rear part of the short spiral drill bit 6 for injecting powdery curing agent; the second injection port 52 communicates with the second material conveying channel 402 between the inner pipe 8 of the central shaft 3 and the central pipe 9 and is arranged at the side rear part of the lower end of the outer frame 28, also for injecting powdery curing agent; the third injection port 53 communicates with the third material conveying channel 403 between the inner pipe 8 and the outer pipe 7 of the central shaft 3 and is arranged inside the vertical outer edge plate 24 for injecting curing agent slurry.

[0108] The combined drill 1 is assembled at the bottom end of the two-way stirring mechanism 61 of the drill rig. The two-way stirring mechanism 61 is successively installed with a three-channel water faucet 62, a double power head 13, an integrated suspension device 63, and an inner and outer active drill pipe 10 from top to bottom; three material conveying channels 4 are arranged inside the central shaft 3, and the curing agent can be conveyed to the first injection port 602, the second injection port 52 and the third injection port 53 through the external material supply pipeline 64, the water faucet 62, the inner and outer active drill pipes 10, the central shaft 3 and the short spiral drill bit 6.

[0109] The use process of the combined drill 1 in this embodiment is basically similar to that described in Embodiment 8, so the implementation process steps of this embodiment will not be repeated here.

[0110] To sum up, the beneficial effects of the present invention include:

[0111] 1. Since the short spiral drill bit 6 is assembled at the lower part of the drill, the powerful spiral self-tapping ability of the short spiral drill bit 6 can solve the construction technical problems of traditional single-direction stirring drills and existing two-way stirring drills that cannot implement large-diameter and large-depth mixing piles in hard soil layers (such as fully weathered, strongly weathered, dense sandy soil and hard plastic clay layers).

[0112] 2. The controlled-speed reverse rotation and upward lifting stirring process is adopted, and the further compaction and strengthening effect of solidified soil can be achieved through the reverse pressure technology of spiral blades, improving the compactness and strength of solidified soil.

[0113] 3. By utilizing the two-way stirring and mutual shearing functions of each frame and adjacent transverse stirring wing plates, the technical problems of the upward discharge of solidified soil along the gaps on the circumferences of the drill and drill pipe during the construction of traditional stirring drills and the stubborn problem of drilling tool sticking in groups during the construction in cohesive soil layers can be solved.

[0114] 4. In terms of construction effect, all kinds of soil bodies and solidifying agents are stirred evenly and fully, which can save a large amount of solidifying agent materials. At the same time, it can ensure the excellent quality of deep mixing piles, shorten the construction period, and reduce costs.

[0115] Although the present disclosure is disclosed as above, the protection scope of the present disclosure is not limited thereto. Those skilled in the art can make various changes and modifications without departing from the spirit and scope of the present disclosure, and these changes and modifications will all fall within the protection scope of the present invention.

Claims

1. A combined drilling tool with a short spiral drill bit, characterized in that, From top to bottom, it successively includes a top joint (5), a central shaft (3), a frame structure (2), and a short helix drill bit of a mixing pile; the top joint (5) is located at the top of the central shaft (3); the central shaft (3) successively includes an outer tube (7), an inner tube (8), and a central tube (9) from outside to inside, and a first material delivery channel (401) is arranged inside the central tube (9); an annular gap between the central tube (9) and the inner tube (8) forms a second material delivery channel (402); an annular gap between the inner tube (8) and the outer tube (7) forms a third material delivery channel (403); the frame structure (2) is connected to the outer peripheral wall of the central shaft (3); the top of the short helix drill bit is fixedly and sealingly connected to the bottom of the central shaft (3); the short helix drill bit includes a drill bit main rod (601), a first injection port (602), short helix blades (603), and a drill tip (604); an injection channel (600) for injecting materials is arranged inside the drill bit main rod (601); the first injection port (602) is arranged at the bottom of the drill bit main rod (601), and the first injection port (602) is communicated with the discharge end of the injection channel (600); the short helix blades (603) are arranged on the outer wall of the drill bit main rod (601); a plurality of plate teeth (605) arranged at intervals are arranged at the upper end of the short helix blades (603); a plurality of cut teeth (606) arranged at intervals are arranged at the lower end of the short helix blades (603); the drill tip (604) is connected to the bottom of the drill bit main rod (601). The rotation expansion angle range of the short helix blades (603) is 0° to 1800°, forming continuous spiral blades of one to five turns; the diameter of the continuous spiral blades is of equal diameter or variable diameter, and the pitch of the continuous spiral blades is of equal pitch or unequal pitch. The short helix blades (603) are composed of a plurality of discontinuous spiral blades (608); the plurality of discontinuous spiral blades (608) are longitudinally arranged at intervals on the outer wall of the drill bit main rod (601); the plurality of cut teeth (606) are arranged at the bottom end of the discontinuous spiral blade (608) located at the bottom. The frame structure (2) is a double-layer frame structure, and the frame structure (2) includes an outer frame (28) and an inner frame (29); the upper end of the outer frame (28) is fixedly connected to the outer side wall of the outer tube (7) of the central shaft (3) through a second fixed ring sleeve (41); the lower end of the outer frame (28) is rotatably connected to the outer side wall of the inner tube (8) of the central shaft (3) through a second annular limiting support bearing sleeve (42), and the outer frame (28) can follow the rotation of the outer tube (7) of the central shaft (3); the upper end of the inner frame (29) is rotatably connected to the outer side wall of the outer tube (7) of the central shaft (3) through a third annular limiting support bearing sleeve (43), and the lower end of the inner frame (29) is fixedly connected to the outer side wall of the inner tube (8) of the central shaft (3) through a third fixed ring sleeve (44), and the inner frame (29) can follow the rotation of the inner tube (8) of the central shaft (3); a plurality of transverse T-shaped stirring vanes (25-3) are also fixedly connected to the outer peripheral wall of the central shaft (3); a fourth transverse stirring vane (25-4) is arranged inside the inner frame (29) at intervals with the plurality of transverse T-shaped stirring vanes (25-3); a plurality of fifth transverse stirring vanes (25-5) are arranged outside the inner frame (29); vertical stirring vanes (291) are also arranged on the upper and lower outer sides of the inner frame (29); a sixth transverse stirring vane (25-6) is arranged inside the outer frame (28) at intervals with the plurality of fifth transverse stirring vanes (25-5).

2. The combined drill tool with a short spiral drill bit according to claim 1, characterized in that, A plurality of shear plates (607) arranged at intervals are provided between adjacent continuous spiral vanes in the vertical direction of the short spiral vane (603).

3. The combined drill tool with a short spiral drill bit according to claim 1, characterized in that, The plate teeth (605) are arranged at the arc-shaped termination edge at the top of the short helical blade (603), and the angle of the plate teeth (605) is similar to the angle of the arc-shaped termination edge at the top of the short helical blade (603); the pick teeth (606) are arranged at the arc-shaped starting edge at the bottom of the short helical blade (603), and the angle of the pick teeth (606) is 15 o ~35 o .

4. The combined drill tool with a short spiral drill bit according to claim 1, characterized in that A first wear-resistant plate (610) is welded to the outer edge of the short spiral vane (603); the drill tip (604) is integrally in a cross-shaped structure, and a plurality of drill tip teeth (609) are provided at the bottom of each branch of the cross-shaped drill tip (604).

5. The combined drilling tool with a short spiral drill bit according to claim 1, characterized in that, It further includes a second injection port (52) and a third injection port (53); the second injection port (52) communicates with the annular gap between the inner tube (8) and the central tube (9), and is arranged at the side rear part of the lower end of the outer frame (28), and the third injection port (53) communicates with the annular gap between the inner tube (8) and the outer tube (7), and is arranged on the inner side of the outer wall of the vertical outer edge plate (24) of the outer frame (28); a second wear-resistant plate (56) is welded to the outer edge of the frame structure (2); an oil injection hole (55) for dynamic seal and lubricating oil is provided on the annular limiting support bearing sleeve of the frame structure (2).

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