A shotcrete excavation structure for large diameter wet shotcrete mixing pile construction drilling tool

Abstract

The invention relates to a grouting excavation structure for a large-diameter wet-jet mixing pile construction drill tool, comprising a drill center rod, a grouting excavation unit is arranged in the radial direction of the drill center rod, the grouting excavation unit comprises a grouting channel and an excavation wing plate, the excavation wing plate is fixed on the outer wall of the drill center rod, one end of the grouting channel is communicated with a slurry passage arranged on the drill center rod, and the grouting channel is located below the excavation wing plate and parallel to the length direction of the excavation wing plate, and a grouting through seam is arranged along the axial direction of the grouting channel; the invention has the characteristics of uniformly spreading curing agent slurry along the radius of the pile body, effectively improving the pile body quality and construction efficiency of the mixing pile, reducing the amount of curing agent, and at the same time effectively preventing the clogging of the grouting pipe and facilitating the cleaning of the blocked pipe.

Description

Technical Field

[0001] The invention belongs to the technical field of underground construction machinery and equipment, and in particular relates to a grouting excavation structure for a large-diameter wet-jet mixing pile construction drill. Background Art

[0002] As a major construction method in the field of foundation treatment engineering technology, deep mixing pile technology has been widely used in the field of engineering construction since the 1960s, including civil engineering, construction engineering, railway engineering, highway engineering, water conservancy engineering, municipal engineering and port engineering. Deep mixing pile engineering technology uses a single-axis or multi-axis mixing drill to input cement and other curing agents into the ground, and mixes them with soft and hard soil to produce a series of physical and chemical reactions between the curing agent and the soil, generating piles, walls and blocks with high strength, good water stability and strong anti-seepage performance. This effectively solves practical engineering problems such as the bearing capacity of composite foundations, the bearing capacity of mixing piles, the bearing capacity of strong core composite piles, the bearing capacity of SMW construction piles, the anti-seepage capacity of water-blocking walls, and the isolation walls and isolation layers of contaminated soil and toxic material landfills.

[0003] Due to the advantages of simple drilling equipment, efficient construction and low cost, deep mixing pile engineering technology has been widely used in the field of civil engineering. However, when designing the drilling tools for mixing pile construction, a grouting port is set on the center rod of the drill bit for grouting, and the sprayed curing agent slurry and the soil are mixed by the stirring blade to form a mixing pile of a certain diameter. However, it is difficult for the slurry around the center rod of the drill bit to achieve the goal of uniform mixing through the stirring disturbance of the soil. Usually, the curing agent is discharged upward along the gap around the drill tool and the drill rod, and the curing agent is accumulated in some areas, especially the central area, which eventually causes the strength of the peripheral cement soil to be much lower than the strength of the central cement soil, and the overall strength of the solidified soil is lower than the design value. Serious engineering quality problems often cause serious engineering safety problems. Especially when the project requires the use of large-diameter and deep mixing piles, the use of conventional grouting port design mixing drills will make the engineering quality and engineering safety risks particularly prominent. The current civil engineering market is in urgent need of solving the above engineering and technical problems. Some existing conventional solutions are: 1. Increasing the grouting pressure, using the jet to send the slurry to the outside of the pile body, or increasing the amount of cement slurry to increase the chance of uniform mixing, but these methods require the addition of additional equipment or increase the amount of materials, and the construction cost increases; 2. Using four-stirring and two-spraying or multi-stirring and multi-spraying processes to increase the mixing time, the uniformity is improved to a certain extent, but the construction efficiency is reduced; 3. Moving the grouting port to the mixing blade, or even adding multiple grouting holes on the mixing blade or the excavation blade to achieve uniform grouting within the radius of the pile body, trying to make up for the defects of the center rod grouting design, which has improved to a certain extent, but still cannot make the slurry cover evenly along the radius, or some of the slurry outlet holes are blocked during the construction process. Therefore, this problem has not been fundamentally solved in the industry. Summary of the invention

[0004] The purpose of the present invention is to overcome the shortcomings of the prior art and to provide a grouting excavation structure for a large-diameter wet spraying mixing pile construction drill, which can evenly spread the curing agent slurry within the radius of the pile body during the construction process. In addition, the stirring disturbance is less than that of the conventional mixing method, so that the mixing effect can be uniform, thereby greatly reducing the strength difference of the mixing pile body and greatly improving the overall strength.

[0005] The objective of the present invention is achieved through the following technical scheme. The grouting and excavation structure of the drill tool for large-diameter wet-jet mixing pile construction includes a drill center rod, and a grouting and excavation unit is provided in the radial direction of the drill center rod. The grouting and excavation unit includes a grouting channel and an excavation wing plate. The excavation wing plate is fixed on the outer wall of the drill center rod, one end of the grouting channel is communicated with the slurry channel provided on the drill center rod, and the grouting channel is located below the excavation wing plate and parallel to the length direction of the excavation wing plate, and a grouting through seam is provided along the axial direction of the grouting channel.

[0006] The beneficial effects of the present invention are as follows: compared with the prior art, by adopting this structure, no matter what kind of mixing drill bit and what kind of mixing process, such as single-axis unidirectional mixing piles, single-axis bidirectional mixing piles, biaxial unidirectional mixing piles, biaxial bidirectional mixing piles, multi-axis mixing piles, etc., the curing agent slurry can be evenly spread within the radius of the pile body by spraying through the seams during the construction process, and the mixing disturbance with fewer mixing times than the conventional mixing method can achieve a uniform mixing effect, thereby achieving a significant reduction in the strength difference of the mixing pile body and a significant improvement in the overall strength. By using this structure, the construction diameter of the mixing pile can reach 3000mm.

[0007] Preferably, the shotcrete through-slit is formed by the bottom plate surface of the excavated wing plate and the notch provided on the shotcrete channel, or the shotcrete through-slit is formed by the opening of the side wall of the shotcrete channel; in this way, different shotcrete through-slits are arranged according to the amount of shotcrete, and at the same time, the through-slit structure design can make the shotcrete through-slit unobstructed by flushing the slurry from the unobstructed part when the shotcrete through-slit is partially blocked, thereby effectively avoiding the problem of blockage of the shotcrete outlet.

[0008] Preferably, the shotcrete through seam is arranged in the shadow overlap area formed between the forward rotating soil facing surface and the reverse rotating soil facing surface of the shotcrete excavation unit; this can effectively prevent soil from entering the shotcrete channel and ensure smooth shotcrete.

[0009] Preferably, the slurry flow area corresponding to the unit length of the shotcrete seam tends to increase in the axial direction of the shotcrete channel; through this structural setting, the curing agent slurry can be relatively evenly distributed to the circumference of each radius, so as to achieve equal curing agent content at each point of the mixing pile body.

[0010] Preferably, a detachable slurry stopper is provided on the axial end face of the other end of the shotcrete passage, thereby greatly reducing the difficulty of clearing the blocked pipe.

[0011] Preferably, the plate surface direction of the excavation wing plate forms an angle θ1 with the cross-sectional direction of the drill center rod, and the range of θ1 is 0 to 45°; it can produce better shear disturbance effect on the soil in front of the plate in the rotation direction, while reducing the increased resistance to the drill bit.

[0012] Preferably, a plurality of cutting plate teeth are fixed on the excavating wing plate, and the cutting plate teeth are located on the side of the shotcrete seam; the cutting speed of the soil can be greatly improved, thereby greatly improving the construction efficiency. At the same time, the curing agent slurry sprayed from the shotcrete seam can enter the soil groove after the cutting teeth excavate, preventing the slurry from flowing randomly, thereby achieving the purpose of uniform spraying.

[0013] Preferably, the cutting direction of the cutting plate teeth forms an angle θ2 with the perpendicular direction of the length direction y of the digging wing plate, and the range of θ2 is 0 to 90°, so that the coverage of the cutting disturbance is wider and more complete, and the cutting effect is better.

[0014] Preferably, the shotcrete excavation unit is located at the lower end of the drill bit center rod, a drill bit joint is provided at the upper end of the shotcrete excavation unit, a stirring blade unit and a free blade are provided on the rod body of the drill bit center rod in sequence from top to bottom, and the stirring blade unit and the free blade are located above the shotcrete excavation unit; thus, the stirring ability of the entire drill bit is better. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 It is a schematic diagram of the structure of the shotcrete excavation unit of the present invention.

[0016] Figure 2 It is a schematic diagram of the structure of the stirring drill bit of the present invention.

[0017] Figure 3 It is a schematic diagram of the main structure of the stirring drill bit of the present invention.

[0018] Figure 4 yes Figure 3 Schematic diagram of the AA cross-section structure.

[0019] Figure 5 yes Figure 3 Schematic diagram of the BB cross-section structure.

[0020] Figure 6 It is a partial schematic diagram of the asymmetric shotcrete through-seam structure of the present invention.

[0021] Figure 7 It is a schematic diagram of the explosion structure of the asymmetric shotcrete channel of the present invention.

[0022] Figure 8 It is a schematic diagram of the asymmetric shotcrete through-seam shape structure of the present invention.

[0023] Fig. 9 It is a partial schematic diagram of the symmetrical shotcrete through-seam structure of the present invention.

[0024] Fig.10 It is a schematic diagram of the explosion structure of the symmetrical shotcrete channel of the present invention.

[0025] Fig.11 It is a schematic diagram of the symmetrical shotcrete through-seam shape structure of the present invention.

[0026] Fig.12 It is a schematic diagram of the positions of the shotcrete passages and shotcrete through-slits of several different structural forms of the present invention.

[0027] The numbers in the accompanying drawings are: 3, drill bit joint; 4, free blade; 7, drill bit center rod; 8, stirring blade unit; 71, slurry channel; 100, shotcrete excavation unit; 101, shotcrete channel; 102, excavation wing plate; 103, shotcrete through seam; 104, shaded overlapping area; 105, slurry stop plug; 106, cutting plate teeth. DETAILED DESCRIPTION

[0028] The present invention will be described in detail below with reference to the accompanying drawings: Figure 2 A stirring drill bit using the shotcrete excavation unit 100 of the present invention is shown, and the stirring drill bit includes a drill bit joint 3, a drill bit center rod 7, stirring blades 8, free blades 4 and a shotcrete excavation unit 100; the shotcrete excavation unit 100 is located at the lower end of the drill bit center rod 7, the upper end of the shotcrete excavation unit 100 is provided with a drill bit joint 3, and the rod body of the drill bit center rod 7 is provided with a stirring blade unit 8 and a free blade 4 in sequence from top to bottom, and the stirring blade unit 8 and the free blade 4 are located above the shotcrete excavation unit 100. The beneficial effects of the present invention are as follows: 1. It solves the technical problem that the curing agent cannot be evenly spread during the construction of traditional mixing piles; 2. It solves the problem that some of the spraying ports are blocked due to porous spraying; 3. It solves the problem that large particles of impurities in the curing agent slurry cannot be discharged from the spraying port, causing the spraying channel to be blocked, thereby greatly reducing the failure rate during construction; 4. The forward and reverse two-way anti-blocking design effectively prevents the soil from pouring into the spraying port, and the spraying port always remains unobstructed, further reducing the failure rate; 5. It solves the problem that the spraying channel is blocked and cannot be cleaned, without the need to replace parts or the entire drill bit; 6. All kinds of soil and curing agent are uniformly and fully mixed as a whole to form a high-strength solidified soil body; 7. Under the condition that the solidified soil reaches the same overall strength, a large amount of curing agent material can be saved; 8. The construction speed and efficiency are greatly improved and the construction period can be shortened; 9. It ensures the high quality of deep mixing piles, engineering safety and cost reduction.

[0029] like Figure 1 As shown, a shotcrete excavation unit 100 is provided in the radial direction of the drill center rod 7. The shotcrete excavation unit 100 includes a shotcrete channel 101 and an excavation wing plate 102. The excavation wing plate 102 is fixed on the outer wall of the drill center rod 7. Figure 4 As shown, one end of the grouting channel 101 is connected to the slurry channel 71 provided on the drill bit center rod 7, and the grouting channel 101 is located below the excavation wing plate 102 and parallel to the length direction of the excavation wing plate 102. The main function of the grouting channel 101 is to guide the curing agent slurry flowing vertically in the grouting channel 101 to the lateral radial direction of the mixing pile, so as to spread it within the radius of the pile body. A grouting slot 103 is provided along the axial direction of the grouting channel 101, as shown in FIG. Figure 6 , Fig. 9 Based on the above technical features, the spraying channel can be in the following forms: Fig.12 As shown in (a), a semicircular shotcrete passage 101 is formed by a half-cut pipe and the lower plane of the excavation wing plate, and a shotcrete through seam 103 is arranged adjacent to the half-cut circular pipe and the excavation wing plate 102; Fig.12 (b) shows a rectangular shotcrete passage 101 formed by a half-cut rectangular tube and the lower plane of the excavation wing plate, and a shotcrete through seam 103 is arranged adjacent to the half-cut rectangular tube and the excavation wing plate 102; Fig.12 (c) shows a circular shotcrete passage 101 formed by a half-cut circular tube and an arc-shaped groove on a digging wing plate 102, and a shotcrete through seam 103 is provided on the half-cut circular tube; Fig.12 (d) shows a semicircular shotcrete passage 101 surrounded by the plane plate and the arc-shaped groove on the excavation wing plate 102, and a shotcrete through-slit 103 is arranged on the plane plate.

[0030] The shotcrete seams 103 are arranged with non-equal widths, and the slurry flow areas corresponding to the unit length generally increase in the direction of slurry flow in the shotcrete channel 101. Since each point in the length direction of the shotcrete excavation unit 100 rotates around the drill center rod 7, the linear speeds thereof are not equal. In order to achieve the goal of consistent curing agent incorporation ratios at various positions of the pile body, the amount of slurry required on the pile body near the periphery is more than that near the inner circle per unit width. By setting the shotcrete seams 103 with the illustrated features, and utilizing the principle that the amount of slurry flowing out of different flow areas is unequal and in a certain proportion, the curing agent slurry can be relatively evenly distributed to the circumference of each radius, thereby achieving equal curing agent content at various points in the stirred pile body. According to the above-mentioned purposes and technical features, the shotcrete seams 103 can be arranged in different shapes, such as Figure 8 (a) shows a stepped shotcrete joint. Figure 8 (b) The trapezoidal shotcrete joint shown in Figure 8 (c) Figure 8 (d) Figure 8 (e) The string-like shotcrete joints shown are Figure 8 (f) Figure 8 The irregular-shaped shotcrete joints shown in (g) are all asymmetric shotcrete joints surrounded by the bottom plate surface of the excavated wing plate and the gap on the shotcrete channel; Fig.11 (a) shows a stepped shotcrete joint. Fig.11 (b) The trapezoidal shotcrete joint shown in Fig.11 (c) Fig.11 (d) Fig.11 (e) The string-like shotcrete joints shown are Fig.11 (f) Fig.11 The irregular shaped shotcrete seam shown in (g) is a symmetrical shotcrete seam formed by directly opening holes on the side wall of the shotcrete channel.

[0031] The grouting seams 103 are arranged in non-uniform widths. Compared with the grouting seams of equal width, under the condition of the same total flow area, the maximum seam width range of the grouting section is larger, and a larger particle size can pass through, which is conducive to smooth grouting.

[0032] The shotcrete through seam 103 is arranged in the shadow overlap area 104 of the forward rotating soil facing surface and the reverse rotating soil facing surface of the shotcrete excavation structure 1. Fig.12 When the drill bit rotates forward or reversely in the deep soil, the soil facing surface will be squeezed by the soil. The shotcrete through seam 103 is arranged in the shadow overlap area 4-1 of the forward rotating soil facing surface and the reverse rotating soil facing surface of the shotcrete excavation unit 100, which can effectively prevent the soil from entering the shotcrete channel and ensure smooth shotcrete.

[0033] like Figure 7 , Fig.10 As shown, a detachable stop plug 105 is provided at the end of the shotcrete channel 101. The outer ring of the stop plug 105 has a threaded structure, which matches the threaded structure of the inner ring at the end of the shotcrete channel 101. When the shotcrete channel 101 is blocked due to the large particles in the slurry or the hardening of the residual slurry due to failure to remove it in time, the stop plug 105 can be removed by tools, and the blockage can be discharged from the large hole at the end of the shotcrete channel 101. After cleaning, the stop plug 105 can be reinstalled, which greatly reduces the difficulty of cleaning the blocked pipe.

[0034] like Figure 3 As shown, the plate surface direction of the excavation wing plate 102 forms an angle θ1 with the cross-sectional direction of the drill center rod 7, and the range of θ1 is 0 to 45°, which is 20° in this example. It can produce better shear disturbance effect on the soil in front of the plate in the rotation direction, while increasing the resistance to the drill bit 20 in general.

[0035] like Figure 5 As shown, a plurality of cutting plate teeth 106 are fixed on the digging wing plate 102, and the cutting direction of the cutting plate teeth 106 forms an angle θ2 with the vertical direction of the extending direction y of the digging wing plate 102, and the range of θ2 is 0 to 90°. In this embodiment, from inside to outside along the y-axis direction, θ2 of the four cutting plate teeth 106 continuously decreases, which are 25°, 20°, 15°, and 10°, respectively.

[0036] The method of using the mixing drill bit for the shotcrete excavation structure includes the following process steps:

[0037] When the pile mixing machine starts construction, the backstage of the drilling rig starts to supply curing agent slurry, which flows into the slurry passage 71 of the drill bit center rod 7 through the drill pipe, further flows into the shotcrete passage 101, and then sprays out through the shotcrete slit 103 of the drill bit. At this time, it indicates that the slurry supply is normal and the channels are not blocked, and the next step can be carried out;

[0038] The drill bit starts to drill down, and the cutting plate teeth 106 first contact the soil to loosen the soil. Then, through the action of the cutting wing plate 102, the soil in front of the plate is provided with upward and forward components, so as to achieve further excavation and disturbance of the soil. At the same time, the grouting seam 103 continues to spray, and the curing agent slurry is evenly spread in the cut soil. When the upper stirring blade unit 8 reaches the soil position for spraying and mixing, the soil containing the slurry is further stirred until it is uniform. When the stirring drill bit drills to the pile bottom elevation, the pile body has been mixed with the curing agent slurry more evenly at this time, and has been stirred once, so that the one-spraying-one-stirring construction is completed.

[0039] Finally, turn off the backstage slurry delivery, the drill bit starts to reverse and lift, the cement soil of the pile body is stirred again, and the uniformity is increased again. When the stirring drill bit is lifted off the ground, the one-spray and two-stirring construction is completed, and the construction is completed; if necessary, repeat the above steps once to complete the two-spray and four-stirring construction; after the construction is completed, pump clean water in the background to flush out the residual slurry or residue in the drill rod, drill center rod, and shotcrete channel. If it cannot be flushed out, remove the slurry stop plug and use tools to clean the shotcrete channel again until it is unobstructed.

[0040] The present invention is not limited to the above-mentioned embodiments. No matter any changes are made in the shape or material composition, any structural design provided by the present invention is a variation of the present invention and should be considered to be within the protection scope of the present invention.

Claims

1. A grouting excavation structure for a large-diameter wet-jet mixing pile construction drill, comprising a drill center rod (7), characterized in that: A shotcrete excavation unit (100) is provided in the radial direction of the drill bit center rod (7), and the shotcrete excavation unit (100) comprises a shotcrete channel (101) and an excavation wing plate (102), wherein the excavation wing plate (102) is fixed to the outer wall of the drill bit center rod (7), one end of the shotcrete channel (101) is communicated with a slurry passage (71) provided on the drill bit center rod (7), and the shotcrete channel (101) is located on the excavation wing plate (102). A shotcrete through-slit (103) is provided below the excavation wing plate (102) and is parallel to the length direction of the excavation wing plate (102), and is provided along the axial direction of the shotcrete passage (101); the shotcrete through-slit (103) is provided in a shadow overlap region (104) formed between the forward rotating soil facing surface and the reverse rotating soil facing surface of the shotcrete excavation unit (100); and the plate surface direction of the excavation wing plate (102) forms an angle θ1 with the cross-sectional direction of the drill bit center rod (7).

2. The grouting excavation structure for large diameter wet spraying mixing pile construction drilling tool according to claim 1 is characterized in that: The shotcrete through seam (103) is formed by the bottom plate surface of the excavation wing plate (102) and the notch provided on the shotcrete channel (101), or the shotcrete through seam (103) is formed by openings on the side wall of the shotcrete channel (101).

3. The grouting excavation structure for large diameter wet spraying mixing pile construction drilling tool according to claim 1, characterized in that: The slurry flow area corresponding to the unit length of the shotcrete through-slit (103) shows an increasing trend in the axial direction of the shotcrete channel (101).

4. The grouting excavation structure for large diameter wet spraying mixing pile construction drilling tool according to claim 1, characterized in that: A detachable grouting stopper (105) is provided on the axial end surface of the other end of the grouting channel (101).

5. The grouting excavation structure for large diameter wet spraying mixing pile construction drilling tool according to claim 1, characterized in that: The angle θ1 ranges from 0° to 45°.

6. The grouting excavation structure for large diameter wet spraying mixing pile construction drilling tool according to claim 1, characterized in that: A plurality of cutting plate teeth (106) are fixed on the excavation wing plate (102), and the cutting plate teeth (106) are located on the side of the shotcrete through seam (103).

7. The grouting excavation structure for large diameter wet spraying mixing pile construction drilling tool according to claim 6, characterized in that: The cutting direction of the cutting plate teeth (106) forms an angle θ2 with the vertical direction of the length direction y of the excavating wing plate (102), and the range of θ2 is 0 to 90 degrees.

8. The grouting excavation structure for large diameter wet spraying mixing pile construction drilling tool according to claim 1, characterized in that: The shotcrete excavation unit (100) is located at the lower end of the drill bit center rod (7), a drill bit joint (3) is provided at the upper end of the shotcrete excavation unit (100), a stirring blade unit (8) and a free blade (4) are provided on the rod body of the drill bit center rod (7) in sequence from top to bottom, and the stirring blade unit (8) and the free blade (4) are located above the shotcrete excavation unit (100).

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