CN109882222B - Small-size double-round hole drilling tool and method for grouting and reinforcing surrounding rock in roadway - Google Patents
Small-size double-round hole drilling tool and method for grouting and reinforcing surrounding rock in roadway Download PDFInfo
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- CN109882222B CN109882222B CN201910272082.8A CN201910272082A CN109882222B CN 109882222 B CN109882222 B CN 109882222B CN 201910272082 A CN201910272082 A CN 201910272082A CN 109882222 B CN109882222 B CN 109882222B
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Abstract
The invention belongs to the technical field of geotechnical engineering. The small-size double-round hole drilling tool comprises a first drill bit, a second drill bit, a gear box and a drill rod, wherein the first drill bit and the second drill bit do not collide when rotating respectively, and intersecting double round holes are drilled; the gear box comprises an input shaft, a first output shaft and a second output shaft, the rotating speeds of the first output shaft and the second output shaft are the same, the first drill bit is connected with the first output shaft, the second drill bit is connected with the second output shaft, and the drill rod is connected with the input shaft. The method for grouting and reinforcing surrounding rock in the roadway comprises the steps of drilling double round holes by adopting the drilling tool, and respectively placing an extensible repeated grouting pipe and an anchor rod body in the double round holes. The grouting reinforcement method of the drilling tool provided by the invention has the advantages of good drilling double round holes effect and high efficiency, can be suitable for large deformation of surrounding rock, has high anchor rod drawing bearing capacity, and can be suitable for rapid construction.
Description
Technical Field
The invention belongs to the technical field of geotechnical engineering, and particularly relates to a small-size double-round hole drilling tool and a method for grouting and reinforcing surrounding rock in a roadway.
Background
The coal mine anchor rod (including anchor cable, hereinafter the same) has the characteristics of small drilling hole, small rod body, small explosive roll and the like, and the annual consumption of the coal mine anchor rod in China exceeds 1 hundred million. Along with the deep arming of coal resources, the development environment is bad, and the accumulated deformation of the roadway exceeds 1 m.
The elongation of the three-small anchor rod is limited, and the anchor rod gradually fails along with the aggravation of surrounding rock deformation and damage. On the basis of the three-small anchor rod, a plurality of students develop constant-resistance or resistance-increasing anchor rods with large elongation rate successively, but the crushing condition of surrounding rock is not improved, because the novel anchor rods have no grouting reinforcement function, and the surrounding rock is only crushed more and more. In order to cope with the long-time continuous deformation and continuously improve the crushing condition of surrounding rock, the technical staff in China develop a repeatable grouting reinforcement method (ZL 201310014588.1) and a side-void repeatable grouting anchor rod (ZL 201510674920.6) technology and successfully apply the repeated grouting anchor rod. However, this technique has three drawbacks: the grouting pipe and the rod body are arranged in the same hole, the rod body can only be in multi-strand tiny dispersion distribution, and the drawing bearing capacity of the anchor rod is limited; secondly, the anchor rod body and the surrounding rock can be adhered together only through grout, and the resin cartridge widely applied to coal mines cannot be used for anchoring, so that the quick construction of a roadway and the stability maintenance of the roadway near a tunnel face are unfavorable; thirdly, the surrounding rock deformation can not be adapted.
In order to adapt to the environment, the technical staff in China want to develop a double-round extendable repeated grouting anchor rod (including anchor ropes and the same as the anchor ropes) suitable for supporting coal mine roadways, and the anchor rod has the characteristics of high strength, early strength, repeated repair and reinforcement of surrounding rocks and the anchor rod, quick construction, stable and quick maintenance and the like, has all the advantages of the resin anchor rod and the side-void repeated grouting anchor rod which are widely applied at present, overcomes the defects of the resin anchor rod and the side-void repeated grouting anchor rod, and is a more ideal coal mine roadway supporting structure. However, the cross section of the anchor rod is a double-round section formed by two intersecting small round holes, and the double round holes with the cross section are drilled in a rock body by adopting the existing drilling tool, so that the time and the labor are wasted, and the effect is poor. Therefore, there is a need to develop a dual round hole drilling tool of small size that fits with it.
Disclosure of Invention
The invention aims to solve the problems and the defects, and provides a small-size double-round hole drilling tool and a method for grouting and reinforcing surrounding rock in a roadway, which can drive two drilling bits to drill crossed double-round holes through transmission of a gear box.
In order to achieve the above purpose, the technical scheme adopted is as follows:
a small-sized double round hole drilling tool, comprising: the first drill bit and the second drill bit do not collide when rotating respectively, and the intersecting double round holes are drilled; the gear box is internally provided with an input shaft, a first output shaft and a second output shaft, the first drill bit is connected with the first output shaft, the second drill bit is connected with the second output shaft, and the rotating speeds of the first output shaft and the second output shaft are the same; and a drill rod connected with the input shaft.
The small-size double-round hole drilling tool comprises a water jacket, wherein water channels are arranged in the input shaft, the first output shaft and the second output shaft and are connected with the water jacket, and an inner cavity of the water jacket is communicated with the water channels in the input shaft, the first output shaft and the second output shaft; the drill rod is a hollow drill rod, and the water channel of the input shaft is communicated with the interior of the hollow drill rod; the water outlet holes of the first drill bit are communicated with the water channel of the first output shaft, and the water outlet holes of the second drill bit are communicated with the water channel of the second output shaft.
According to the small-size double-round hole drilling tool, the first drill bit and the second drill bit are in a straight-line shape, a Y-shaped drill bit or a combined drill bit, and the combined drill bit is in a cylindrical-Y-shaped combined drill bit or a cylindrical-straight-shaped combined drill bit.
According to the small-size double-round hole drilling tool, the drill rod is connected with the input shaft, the first output shaft is connected with the first drill bit, and the second output shaft is connected with the second drill bit in a taper mode.
According to the small-size double round hole drilling tool, the diameters of the first drill bit and the second drill bit are the same or different.
According to the small-size double-round hole drilling tool, the input shaft, the first output shaft and the second output shaft are connected with the gear box through bearings, the input shaft is arranged in the middle of the gear box, and the first output shaft and the second output shaft are arranged on two sides of the input shaft; the first output shaft and the second output shaft are in matched meshed transmission with the input shaft through a gear set, or the first output shaft and the input shaft are in matched meshed transmission through the gear set, and the second output shaft and the first output shaft are in matched meshed transmission through the gear set.
A method for grouting and reinforcing surrounding rock of a roadway comprises the following steps: a. preparing a grouting pipe and an anchor rod body; b. drilling two intersecting drilling holes, namely a first drilling hole and a second drilling hole by adopting any small-size double-round hole drilling tool, and continuously drilling at the second drilling hole position by adopting a single-hole drilling bit after reaching the depth of the grouting pipe until reaching the depth required by the anchor rod; c. placing a grouting pipe in the first drilling hole; d. placing an anchor rod body in the second drilling hole, and anchoring the anchor rod body; e. performing pressure grouting by using a repeatable grouting pipe, and flushing the inside of the grouting pipe after the grouting pipe is completed; f. according to the deformation and damage condition of surrounding rock or the stress descending condition of the anchor rod, grouting reinforcement and restoration are carried out on the surrounding rock and the anchor rod through the repeatable grouting pipe at proper time, so that the surrounding rock and the anchor rod can keep higher strength or bearing capacity permanently.
According to the method for reinforcing surrounding rock by grouting in a roadway, the grouting pipe is an extensible repeated grouting pipe, and the extensible repeated grouting pipe comprises: the grouting pipe comprises a plurality of sections of grouting pipe sections, wherein grouting pipe sections are provided with grouting small holes; the butt joint unit is connected and arranged between two adjacent grouting pipe sections, and the two adjacent grouting pipe sections are connected in a relatively telescopic sealing manner through the butt joint unit; the first flexible sleeve is sleeved on the outer wall of the grouting pipe section, and corresponds to the grouting small hole; and the second flexible sleeve is sleeved outside the butt joint unit and on the grouting pipe section, and a grout outlet seam is formed between the first flexible sleeve and the second flexible sleeve.
According to the method for grouting and reinforcing surrounding rock of the roadway, the butt joint unit comprises: a plurality of pi-shaped iron hooks; the convex joint is arranged at the lower end of the grouting pipe section at the upper section, and a plurality of hook holes matched with one foot of the n-shaped iron hook are uniformly distributed on the outer wall of the grouting pipe section adjacent to the convex joint in the circumferential direction; and the concave joint is arranged at the upper end of the lower grouting pipe section, the concave joint is tightly sleeved with the convex joint in a matched oiling way, and a plurality of sliding hook grooves matched with the other foot of the pi-shaped iron hook are uniformly distributed on the periphery of the outer wall of the concave joint.
According to the method for grouting and reinforcing surrounding rock of the roadway, the first flexible sleeve and the second flexible sleeve are all made of a plurality of layers of rubber films.
By adopting the technical scheme, the beneficial effects are that:
according to the scheme, the small-size double-round hole drilling tool is characterized in that a drill rod drives two drill bits to drill intersecting double round holes through transmission of a gear box, and as the two drill bits drill simultaneously, the parallelism of two axial leads of the double round holes is good, the drilling is formed at one time, the drilling effect is good, and the efficiency is high; when the drilling machine applies spinning action to the hollow drill rod, pressure is transmitted to the gear box shell through the bearing, the gear box shell is further transmitted to the bearing supporting the output shaft in the gear box, the bearing supporting the output shaft in the gear box is further transmitted to the output shaft, the output shaft is further transmitted to the drill bit, the drill bit is pressed towards the rock face, torque force formed by rotation of the hollow drill rod drives the driven gears on two sides to rotate through the input shaft and the main gear, the driven gears on two sides are further transmitted to the drill bit to cut surrounding rock at the bottom of the hole, finally, high-pressure water enters a water channel of the input shaft through the hollow drill rod and moves to an inner cavity of the water jacket, passes through the water channel of the output shaft and enters the water channel of the drill bit, and finally is sprayed out of a cutting tool of the drill bit, so that the drill bit is cooled, the property of the rock mass at the cutting face is changed to a certain extent, the cut rock scraps are easier to be brought out of the drill hole, and the continuity of the drilling process is good.
According to the scheme of the invention, the repeatable grouting pipe with elongation characteristic and the resin anchor rod body (including the anchor rod body with large elongation such as a common anchor rod body and a constant-resistance or resistance-increasing anchor rod body) are placed in two intersecting drilling holes, and the repeatable grouting pipe automatically stretches along with the deformation of the roadway surrounding rock, so that the defect that the side-void repeatable grouting anchor rod cannot adapt to the large deformation of the surrounding rock is overcome; according to the deformation and damage conditions of surrounding rocks, the repeatable grouting pipe is utilized to timely reinforce the anchor rods for cracking or crushing the surrounding rocks and the anchoring solidified bodies, so that the anchor rods are repaired, the strength of the surrounding rocks is reinforced, the strength of the surrounding rocks is kept high, and the repeated grouting pipe is extremely beneficial to the stability of the roadway under the action of the stress of the surrounding rocks. In addition, because the anchoring section of the anchor rod body or the inner end of the anchor rod body is an independent hole, the condition of the anchor rod body is the same as that of a three-small anchor rod of a coal mine, even if the anchor rod is anchored in full length, the condition of the rod body hole is basically the same as that of the three-small anchor rod after a grouting pipe is firstly placed, and therefore the defects that the first two defects of the side-void repeatable grouting anchor rod, namely that the rod body can only be in multi-strand tiny dispersion distribution and the drawing bearing capacity of the anchor rod is limited, and that the anchor rod body and surrounding rock can only be adhered together by grout, the anchor rod cannot be anchored by resin cartridges widely applied to the coal mine, and the defects of quick construction of a roadway and stable roadway near a tunnel face are overcome. Simultaneously, it still possesses the full advantage of the repeatable slip casting stock of side sky. Therefore, the roadway grouting reinforcement method has better reinforcement effect.
The scheme of the invention has the advantages that the combination of the extendable repeated grouting pipe and the anchor rod has better mutual protection effect than the effect when the extendable repeated grouting pipe and the anchor rod are separated. Because research and engineering practice show that the grouting effect exists in an optimal area with the grouting pipe as the center, particularly in a fractured rock mass, the extendable repeated grouting pipe can well repair the cracking of the anchor rod which is close to the extendable repeated grouting pipe. On the other hand, engineering practice has also proved that after surrounding rock is broken, the rock blocks are discontinuously displaced along the circumferential direction of the roadway and are rotated, and the deformation has a destructive effect on the grouting pipe, however, the grouting pipe of the technology is well protected by the anchor rod due to the close proximity of the anchor rod. Based on the method, the comprehensive effect of the method for reinforcing the surrounding rock by grouting the roadway is definitely better than the superposition of the discrete effects of the method and the surrounding rock. In addition, the appearance of the double-round drilling tool promotes the generation of a double-hole (double-round drilling), and two independent drilling holes are needed for the separated repeatable grouting pipe and the anchor rod body, so that the technology has obvious advantages in terms of engineering quantity, engineering cost and construction efficiency.
Drawings
In order to more clearly illustrate the technical solution of the embodiments of the present invention, the following description will briefly explain the drawings of the embodiments of the present invention. Wherein the showings are for the purpose of illustrating some embodiments of the invention only and not for the purpose of limiting the same.
Fig. 1 shows a schematic cross-sectional structure of a small-sized double round hole drilling tool according to an embodiment of the present invention.
Figure 2 shows a schematic cross-sectional view of A-A of figure 1.
FIG. 3 illustrates one of the schematic positional relationship of the first drill bit and the second drill bit relative to the gear case edge according to an embodiment of the present invention.
FIG. 4 shows a second schematic view of the positional relationship of the first drill bit and the second drill bit relative to the gear case edge according to an embodiment of the present invention.
Fig. 5 shows a schematic cross-sectional structure of a water jacket according to an embodiment of the present invention.
Fig. 6 shows one of the structural schematic diagrams of the arrangement of the first drill bit and the second drill bit according to the embodiment of the present invention.
Fig. 7 shows a second schematic structural view of an arrangement of a first drill bit and a second drill bit according to an embodiment of the present invention.
Fig. 8 shows a third schematic structural view of the arrangement of the first drill bit and the second drill bit according to the embodiment of the present invention.
Fig. 9 shows a fourth schematic structural view of an arrangement of a first drill bit and a second drill bit according to an embodiment of the present invention.
Fig. 10 is a schematic side view of a drilling tool according to an embodiment of the present invention, in which the first drill bit is a cylindrical-Y-shaped combination drill bit and the second drill bit is a Y-shaped drill bit.
Fig. 11 is a schematic view showing the positional relationship of the first drill bit to the gear case edge when the first drill bit is a cylindrical-Y-shaped combination drill bit and the second drill bit is a Y-shaped drill bit according to an embodiment of the present invention.
FIG. 12 shows a schematic structural view of an extensible re-grouting pipe according to an embodiment of the present invention;
fig. 13 shows a schematic structural view of a male and female joint connection according to an embodiment of the present invention.
Fig. 14 shows a schematic view of the installation of an anchor rod and an extendable re-grouting pipe in a first borehole and a second borehole according to an embodiment of the present invention.
Fig. 15 shows a schematic A-A sectional structure of fig. 14.
Number in the figure:
100 is a first drill bit, 101 is a drill bit base, 102 is a cutting tool, 200 is a second drill bit, 300 is a gear box, 301 is an input shaft, 3011 is a driving gear, 302 is a first output shaft, 3021 is a first driven gear, 303 is a second output shaft, 3031 is a second driven gear, 304 is a water jacket, 305 is a first sleeve hole, 306 is a water outlet hole, 307 is a second sleeve hole, 308 is a third sleeve hole, 309 is a first bearing, 310 is a second bearing, 311 is a third bearing, 312 is a fourth bearing, 313 is a fifth bearing, 314 is a light hard material, 400 is a drill rod, 1 is a second flexible sleeve, 2 is an "pi" shaped iron hook, 3 is a male joint, 4 is a female joint, 5 is a grout outlet hole, 6 is a grouting pipe section, 7 is a sliding hook groove, 8 is a first flexible sleeve, 9 is a grout solidified body, 10 is a resin solidified body, 11 is a backing plate, 12 is a grout plug, 13 is a lock, and 14 is a rod body.
Detailed Description
In order to make the objects, technical features and technical effects of the technical solution of the present invention more clear, an exemplary solution of the embodiment of the present invention will be clearly and completely described below with reference to the accompanying drawings of the specific embodiment of the present invention. It will be apparent that the described embodiments are some, but not all, embodiments of the invention. All other embodiments, which can be made by a person skilled in the art without creative efforts, based on the described embodiments of the present invention fall within the protection scope of the present invention.
Referring to fig. 1-11, the present embodiment discloses a small-sized double round hole drilling tool, which includes a first drill bit 100, a second drill bit 200, a gear box 300 and a drill rod 400, wherein the first drill bit 100 and the second drill bit 200 are staggered, the first drill bit 100 and the second drill bit 200 do not collide when rotating respectively, and intersecting double round holes are drilled; the gearbox 300 is internally provided with an input shaft 301, a first output shaft 302 and a second output shaft 303, the first drill bit 100 is connected with the first output shaft 302, the second drill bit 200 is connected with the second output shaft 303, the rotation speeds of the first output shaft 302 and the second output shaft 303 are the same, namely the angular speeds are the same, in the embodiment, the gearbox 300 is a rectangular box body, and when drilling, the gearbox 300 synchronously moves downwards along with the drill bit, but the gearbox 300 does not rotate, so that the cross section of the gearbox 300 does not exceed the cross section of the double round holes; drill rod 400 is coupled to input shaft 301.
Optionally, the drill rod 400 is connected with the input shaft 301, the first output shaft 302, the first drill bit 100, the second output shaft 303 and the second drill bit 200 by adopting taper, and the taper connection has good concentricity and is convenient to disassemble and assemble.
Alternatively, the drill rod 400 is screwed to the input shaft 301, the first output shaft 302 is screwed to the first drill bit 100, and the second output shaft 303 is screwed to the second drill bit 200.
In the embodiment of the present invention, the diameter of the circular hole of the double circular hole is Φ30 to Φ50, so the gear box 300 is also a micro gear box.
In the embodiment of the invention, a water jacket 304 is further arranged in the gear box 300, water channels are arranged in the input shaft 301, the first output shaft 302 and the second output shaft 303, and are connected with the water jacket 304, and the inner cavity of the water jacket 304 is communicated with the water channels in the input shaft 301, the first output shaft 302 and the second output shaft 303; the drill rod 400 is a hollow drill rod, and the water channel of the input shaft 301 is communicated with the interior of the hollow drill rod; the first drill bit 100 and the second drill bit 200 are respectively provided with water outlets so as to be cooled by water during drilling, the water outlets of the first drill bit 100 are communicated with the water channel of the first output shaft 302, and the water outlets of the second drill bit 200 are communicated with the water channel of the second output shaft 303.
Optionally, the water jacket 304 is disposed in the gear box 300, a first sleeve hole 305 communicated with the inner cavity of the water jacket is disposed in the middle of the water jacket 304, a water outlet hole 306 communicated with the first sleeve hole 305 is disposed on the input shaft 301 at a position matched with the first sleeve hole 305, and a dynamic sealing structure is disposed on the input shaft 301 at a position matched with the first sleeve hole 305; the water jacket 304 is also provided with a second sleeve hole 307 and a third sleeve hole 308 which are communicated with the inner cavity of the water jacket, the position, matched with the second sleeve hole 307, of the first output shaft 302 is provided with a water inlet hole communicated with the second sleeve hole 307, the position, matched with the second sleeve hole 307, of the first output shaft 302 is provided with a dynamic sealing structure, the position, matched with the third sleeve hole 308, of the second output shaft 303 is provided with a water inlet hole communicated with the third sleeve hole 308, and the position, matched with the third sleeve hole 308, of the second output shaft 303 is provided with a dynamic sealing structure.
As shown in fig. 1, in one possible embodiment of the present invention, the input shaft 301, the first output shaft 302 and the second output shaft 303 are all connected to the gear box 300 through bearings, the input shaft 301 is disposed at the middle of the gear box 300, the first output shaft 302 and the second output shaft 303 are disposed at both sides of the input shaft 301, and in particular, the input shaft 301 is connected to the gear box 300 through a first bearing 309 disposed on the upper end side wall of the gear box 300; the first output shaft 302 is connected with the gear box 300 through a second bearing 310 and a third bearing 311, the second bearing 310 is arranged inside the gear box, and the third bearing 311 is arranged on the side wall of the lower end of the gear box 300; the second output shaft 303 is connected to the gear case 300 through a fourth bearing 312 and a fifth bearing 313, the fourth bearing 312 is provided inside the gear case 300, the fifth bearing 313 is provided on a lower end side wall of the gear case 300, and further, mounting seats for mounting the first bearing, the second bearing, the third bearing, the fourth bearing and the fifth bearing are cast or connected to the gear case 300 through fasteners.
Alternatively, the larger void within the gearbox 300 is filled with a light hard material 314 and serves to stabilize the components within the gearbox. The gearbox 300 may be removable, for example, the gearbox 300 may be made as a separate piece that can be connected to each other to facilitate cleaning and replacement of components within the box.
Optionally, the input shaft 301 is connected to the driving gear 3011 by a spline or by taper fit; the first output shaft 302 is connected with a first driven gear 3021 matched with the driving gear 3011 through a spline or through taper fit, and the second output shaft 303 is connected with a second driven gear 3031 matched with the driving gear 3011 through a spline or through taper fit.
In addition, since the sizes of the driving gear 3011, the input shaft 301, the first output shaft 302, the first driven gear 3021, the second output shaft 303, and the second driven gear 3031 are relatively small, the input shaft 301 and the driving gear 3011 may be provided as a single body, the first output shaft 302 and the first driven gear 3021 may be provided as a single body, and the second output shaft 303 and the second driven gear 3031 may be provided as a single body.
In another possible embodiment of the present invention, not shown in the drawings, the diameters of the first drill bit 100 and the second drill bit 200 are different, the input shaft 301, the first output shaft 302 and the second output shaft 303 are all connected with the gear box 300 through bearings, the input shaft 301 is disposed in the middle of the gear box 300, and the first output shaft 302 and the second output shaft 303 are disposed on both sides of the input shaft 301; the input shaft 301 is connected with a driving gear, the second output shaft 303 is provided with a second driven gear matched with the driving gear, the second output shaft 303 is also provided with a second driving gear, and the first output shaft 302 is provided with a first driven gear matched with the second driving gear.
Optionally, in the embodiment of the present invention, the first drill bit 100 and the second drill bit 200 are a straight drill bit or a Y-shaped drill bit or a combination drill bit, wherein the combination drill bit is a cylindrical-Y-shaped combination drill bit or a cylindrical-straight combination drill bit, and each of the straight drill bit or the Y-shaped drill bit or the cylindrical-straight/Y-shaped combination drill bit is composed of a drill bit base 101 and a cutting tool 102 fixedly connected to the drill bit base 101; the cylindrical-one/Y-shaped combined drill bit is characterized in that the base of the one-shaped drill bit or the Y-shaped drill bit is actually protruded at the central part of the base of the one-shaped drill bit, the height of the protruded part is equivalent to that of the base of the other drill bit, and the free end of the protruded part is provided with a cutting tool. In practice, a small-sized common coal mine drill bit is embedded in the straight or Y-shaped drill bit. The three cutters 102 of the Y-shaped drill bit of the present embodiment are uniformly distributed in the circumferential direction, and the straight or Y-shaped drill bit or the cylindrical-straight/Y-shaped combined drill bit are single-hole drill bits (many variations thereof), and detailed construction thereof is not repeated.
The small-size double-round hole drilling tool of the embodiment is not only suitable for forming holes of three small anchor rod holes in a coal mine, but also suitable for double round holes with other sizes in geotechnical engineering.
Theoretically, to ensure that the two bits do not collide, when the first bit 100 and the second bit 200 are both in-line bits, the arc intersecting the circle that the cutting tool cuts is 90 degrees at maximum, and when the two bits are both Y-shaped bits, the arc intersecting the circle is 60 degrees at maximum, and if the influence of the thickness of the cutting tool is considered, the intersecting arc that does not collide should be smaller than the theoretical maximum value described above.
As shown in fig. 3, the first drill bit 100 and the second drill bit 200 are both in-line type, the first drill bit 100 and the second drill bit 200 are vertically arranged relative to each other, the first drill bit 100 and the second drill bit 200 rotate at the same angular velocity, and the two drill bits do not collide.
As shown in fig. 4, the first drill bit 100 and the second drill bit 200 are both Y-shaped, the first drill bit 100 and the second drill bit 200 are disposed at the same angular orientation, the first drill bit 100 and the second drill bit 200 rotate at the same angular velocity, and the two drill bits do not collide.
As shown in fig. 6, one possible arrangement of the first drill bit 100 and the second drill bit 200 of the present invention is: when the diameters of the first drill bit 100 and the second drill bit 200 are the same, and the first drill bit 100 and the second drill bit 200 are straight-line drill bits, and the intersecting circular arcs of the two intersecting circles are smaller than 90 degrees, when the intersecting angles of the two straight-line drill bits are set within a certain range, the two intersecting circular arcs can not collide in the respective rotation processes, for example, when the intersecting angles of the two intersecting circular arcs are 79 degrees, the intersecting angles of the two straight-line drill bits are set between 79 degrees and 101 degrees, the first drill bit 100 and the second drill bit 200 rotate clockwise at the same angular velocity, and the two drill bits do not collide.
The reason why the arc of intersection of two intersecting circles is smaller than 90 degrees is that: if the arc of intersection of the two intersecting circles is greater than 90 degrees, then the two bits collide at their respective rotations Cheng Zongneng, regardless of the relative position of the two bits.
As shown in fig. 7, another possible arrangement of the first drill bit 100 and the second drill bit 200 of the present invention is: when the diameters of the first drill bit 100 and the second drill bit 200 are the same, and the first drill bit 100 and the second drill bit 200 are Y-shaped, the circular arc intersecting the two intersecting circles of the double round holes is less than or equal to 60 degrees, the two Y-shaped drill bits can be arranged in the same direction, or staggered from the same direction by a certain angle, the first drill bit 100 and the second drill bit 200 rotate clockwise at the same angular velocity, and the two drill bits cannot collide.
As shown in fig. 8, another possible arrangement of the first drill bit 100 and the second drill bit 200 of the present invention is: when the diameters of the first drill bit 100 and the second drill bit 200 are different, and the first drill bit 100 and the second drill bit 200 are both straight drill bits, the intersecting angles of the two straight drill bits are set within a certain range, and the two straight drill bits may not collide during the respective rotation processes.
As shown in fig. 9, another possible arrangement of the first drill bit 100 and the second drill bit 200 of the present invention is: when the diameters of the first drill bit 100 and the second drill bit 200 are different, and the first drill bit 100 and the second drill bit 200 are Y-shaped, but when the circular arcs intersecting two intersecting circles of the double round holes are smaller than or equal to 60 degrees for the large round hole, the two Y-shaped drill bits can be arranged in the same direction, or staggered from the same direction by a certain angle, the first drill bit 100 and the second drill bit 200 rotate clockwise at the same angular velocity, and can not collide in the respective rotation process.
The first drill 100 and the second drill 200 of the present invention may be combined with each other, one of which is a straight or Y-shaped drill, wherein the combined drill bit can be a cylindrical-linear combined drill bit and a cylindrical-Y-shaped combined drill bit. As shown in fig. 10 to 11, when one of the first drill bit 100 and the second drill bit 200 of the present invention is a Y-shaped drill bit and the other is a cylindrical-Y-shaped composite drill bit, the Y-shaped drill bit and the cylindrical drill bit in the composite drill bit are in the same plane, and the Y-shaped drill bit in the composite drill bit and the Y-shaped drill bit connector are in the same plane, but these two planes are not intersected in space. Therefore, when the diameters of the Y-shaped drilling tool parts of the two drill bits are the same, equal-diameter double-circle drilling holes with high overlapping degree can be drilled. Similarly, when the diameters of the two Y-shaped drilling tool parts are different, the different-diameter double-circle drilling holes with high overlapping degree can be drilled. That is, the combination of the drill bits, the first drill bit 100 and the second drill bit 200 rotate in the same direction at the same angular velocity, and the two drill bits do not collide during the respective rotation, and double-circle drilling with high overlapping degree can be obtained as long as the circular range of each cutting tool is not overlapped with the part of the same plane of the other drill bit.
In addition to not colliding with the two drills during drilling, care should be taken to ensure that the gearbox follows the drill in the double round hole, i.e. the size of the double round hole should also be such as to accommodate the entry of the gearbox. This means that the two bores must be cut to a certain extent. When two drill bits of the same design and matching type are encountered and the gear box cannot follow the drill, one drill bit is replaced by the combined drill bit, so that the problem can be solved.
The above combinations of the first drill bit 100 and the second drill bit 200 of the present invention are merely illustrative and not exhaustive, and those skilled in the art can easily derive other kinds of combinations from calculation or reasoning.
The drilling steps of the small-size double-round hole drilling tool are as follows:
1. the bit size and type are selected. And selecting proper drill bit size according to the design requirement of the double round holes, and determining the type of the drill bit according to the hardness of the rock.
2. And (5) positioning a hole site.
3. The rig was in place and inspected for hydro-electric (electrically driven) or hydro-pneumatic (pneumatically driven).
4. Drilling. The drill bit is aligned with a hole site, the drilling machine is started, the drilling machine applies spinning action to the hollow drill rod 400, wherein pressure is transmitted to a gear box shell through a bearing connected between the input shaft 301 and the gear box 300, the gear box shell is further transmitted to a bearing supporting an output shaft in the gear box, the bearing supporting the output shaft in the gear box 300 is further transmitted to the output shaft, the output shaft is further transmitted to the drill bit, the drill bit is pressed towards a rock face, torque formed by rotation of the hollow drill rod is transmitted to the output shaft through the input shaft and a main gear, the driven gears on two sides rotate, the rotation is further transmitted to the drill bit by the driven gears on two sides, surrounding rock at the hole bottom is cut, finally, high-pressure water enters a water channel of the input shaft 301 through the hollow drill rod and moves to a water jacket cavity through the water channel of the output shaft, enters the water channel of the drill bit, and finally is sprayed out of a cutting tool of the drill bit, so that the drill bit is cooled, the property of the rock body at the cutting face is changed to some extent, the cut rock cuttings are easier, and the cut rock cuttings are brought out of the drill hole. And drilling until the depth of the double round holes reaches the design requirement.
5. Repeating the above steps to finish drilling of other double round holes.
As shown in fig. 12-15, the invention also discloses a method for grouting and reinforcing surrounding rock in a roadway, which comprises the following steps:
1. according to the engineering requirements of the roadway, determining the length of the anchor rod through design calculation, and selecting an anchor rod body;
2. determining the length of the extendable repeated grouting pipe and the number of butt joint units according to the type of the anchor rod (end anchor, lengthened anchor and full-length anchor), the length of the anchor rod, the elongation of the anchor rod and the possible maximum deformation of surrounding rock;
3. processing and assembling the extensible repeated grouting pipe, processing an n-shaped iron hook 2, processing a hook hole at a convex joint position of a multi-section grouting pipe section as shown in fig. 13, processing a sliding hook groove at a concave joint position, tightly sleeving the multi-section grouting pipe section 6 by oiling, coating a lubricant on the outer wall of the pipe, sleeving a first flexible sleeve and a second flexible sleeve, and keeping gaps between the first flexible sleeve and the second flexible sleeve as few as possible so as not to influence the extension movement of the later grouting pipe along with the deformation of surrounding rock;
4. drilling, namely, drilling two intersecting drilling holes, namely a first drilling hole and a second drilling hole by adopting any small-size double-round hole drilling tool, and replacing the drilling holes with single-hole drilling bits when the two intersecting drilling holes reach a specified position (corresponding to the total length of a grouting pipe), and continuously drilling at the second drilling hole position until the depth required by an anchor rod is reached;
5. placing grouting pipes in the holes, inserting the assembled extendable repeated grouting pipes, and if the total length of the grouting pipes is too long (the situation that the total length cannot be installed once due to the limited space), randomly combining the sections and assembling the grouting pipes at the hole openings for the second time;
6. the installation of the anchor rod body 14 is that, as shown in fig. 14, resin cartridges are put into a second drilling hole, the anchor rod body 14 or a simple special conveying rod is used for putting the anchor rod bodies into the hole bottoms one by one, in the process of putting the anchor rod bodies into the hole bottoms, the positions of the extendable repeated grouting pipes are automatically aligned, the anchor rod body 14 is connected by an anchor rod drilling machine, the drilling machine is started, and the anchor rod body 14 is spun into and fully agitates the resin cartridges to form a resin solidified body 10;
7. a grout stop plug 12, an anchor rod backing plate 11 and a lock 13 are arranged, and an anchor rod body 14 is tensioned and locked;
8. grouting is performed through the extendable repetitive grouting pipe, so that the grouting liquid fills the gaps outside the grouting pipe and the anchor rod body 14. If the slurry is to be anchored, pressure grouting is required. After grouting is completed, the inside of the grouting pipe is flushed.
9. Grouting is performed timely according to the requirement, particularly when deformation and damage of surrounding rock reach a certain degree or the axial force of the anchor rod is obviously reduced, so that further deterioration of the strength or the integrity of the surrounding rock is prevented, the double-circle repeatable grouting anchor rod is repaired, the bearing capacity of the anchor rod is improved, and the extendable repeated grouting pipe has extensibility and repeated grouting performance, so that the step can be repeatedly performed.
The extendable repeated grouting pipe in the embodiment comprises a plurality of sections of grouting pipe sections 6, a butt joint unit, a first flexible sleeve 8 and a second flexible sleeve 1, wherein two adjacent grouting pipe sections 6 are connected in a relatively telescopic sealing manner through the butt joint unit; the first flexible sleeve 8 is sleeved on the outer wall of the grouting pipe section, and the first flexible sleeve 8 corresponds to the grouting small hole; the second flexible sleeve 1 is sleeved on the outer side of the butt joint unit and the grouting pipe section 6, a grout outlet seam is formed between the first flexible sleeve 8 and the second flexible sleeve 1, the number of the butt joint units is determined according to the length of the anchor rod and the possible deformation, and 2-4 grout outlet small holes 5 are uniformly distributed on the grouting pipe along the circumference at intervals of a certain distance (usually 0.5-1 m) in the axial direction; the first flexible sleeve 8 is arranged to enable the grouting small hole 5 to only grouting outwards from the grouting pipe section and not to return grouting from the outside of the grouting pipe section to the inside of the grouting hole, and the second flexible sleeve 1 is arranged to enable the outer pipe wall of the grouting pipe section not to be in direct contact with the slurry solidifying body 9, so that the grouting pipe section is not fixed by the slurry solidifying body 9, and a certain relative mobility exists between the grouting pipe section and the second flexible sleeve 1.
Alternatively, one possible structure of the docking unit is: the butt joint unit comprises a plurality of pi-shaped iron hooks 2, a convex joint 3 arranged at the lower end of the upper section grouting pipe section 6 and a concave joint 4 arranged at the upper end of the lower section grouting pipe section 6; the concave joint 4 is matched and sleeved with the convex joint 3, and a plurality of hook holes matched with one foot of the pi-shaped iron hook 2 are uniformly distributed on the circumference of the outer wall of the grouting pipe section 6 adjacent to the convex joint 3; a plurality of sliding hook grooves 7 matched with the other feet of the pi-shaped iron hook-shaped iron hooks 2 are uniformly distributed on the periphery of the outer wall of the concave connector 4, and the pi-shaped iron hook-shaped iron hooks 2 slide in the sliding hook grooves 7 along the axial direction; in each butt joint unit, 2-3 iron hooks 2 in an pi shape can be arranged along the circumference according to the thickness of a grouting pipe, and correspondingly, the hook holes and the sliding hook grooves 7 are also arranged in a matched mode.
Optionally, the first flexible sleeve 8 and the second flexible sleeve 1 are all a plurality of layers of rubber films, preferably, the first flexible sleeve 8 and the second flexible sleeve 1 are all 2-3 layers of rubber films, and after the surface layer rubber films are damaged in the process of inserting the extendable repeated grouting pipe into the drilled hole, the inner layer rubber films can also act.
Unless defined otherwise, technical or scientific terms used herein should be given the ordinary meaning as understood by one of ordinary skill in the art to which this invention belongs. The terms "a" and "an" and "the" and similar referents used in the specification and claims of the present application are not to be construed to cover any order, quantity, or importance, but rather are used to distinguish between the various components. Likewise, the terms "a" or "an" and the like do not necessarily denote a limitation of quantity. The word "comprising" or "comprises", and the like, means that elements or items preceding the word are included in the element or item listed after the word and equivalents thereof, but does not exclude other elements or items. "upper", "lower", "left", "right", etc. are used merely to indicate relative positional relationships, which may also be changed when the absolute position of the object to be described is changed.
While the exemplary embodiments of the present invention have been described in detail with reference to the preferred embodiments, those skilled in the art will appreciate that various modifications and adaptations can be made to the above-described specific embodiments and that various combinations of the features and structures can be made without departing from the scope of the present invention as defined in the appended claims.
Claims (9)
1. The method for grouting and reinforcing surrounding rock of the roadway is characterized by comprising the following steps of:
a. preparing a grouting pipe and an anchor rod body;
b. drilling two intersecting drilling holes, namely a first drilling hole and a second drilling hole by adopting a small-size double-round hole drilling tool, and continuously drilling at a second drilling hole position by adopting a single-hole drilling bit after reaching the depth of a grouting pipe until reaching the depth required by an anchor rod;
c. placing a grouting pipe in the first drilling hole;
d. placing an anchor rod body in the second drilling hole, and anchoring the anchor rod body;
e. performing pressure grouting by using a repeatable grouting pipe, and flushing the inside of the grouting pipe after the grouting pipe is completed;
f. grouting reinforcement and restoration are carried out on the surrounding rock and the anchor rod through the repeatable grouting pipe at proper time according to the deformation and damage condition of the surrounding rock or the stress descending condition of the anchor rod, so that the surrounding rock and the anchor rod can keep higher strength or bearing capacity for a long time;
the small-size double round hole drilling tool includes:
the first drill bit and the second drill bit do not collide when rotating respectively and can drill intersecting double round holes;
the gear box is internally provided with an input shaft, a first output shaft and a second output shaft, the first drill bit is connected with the first output shaft, the second drill bit is connected with the second output shaft, and the rotating speeds of the first output shaft and the second output shaft are the same; and
and the drill rod is connected with the input shaft.
2. The method for grouting surrounding rock reinforcement of a roadway of claim 1, wherein the first drill bit and the second drill bit are a straight drill bit or a Y-shaped drill bit or a combined drill bit, and the combined drill bit is a cylindrical-Y-shaped combined drill bit or a cylindrical-straight combined drill bit.
3. The method for grouting reinforcement of surrounding rock according to claim 1, wherein,
the inner cavity of the water jacket is communicated with the water channels in the input shaft, the first output shaft and the second output shaft;
the drill rod is a hollow drill rod, and the water channel of the input shaft is communicated with the interior of the hollow drill rod;
the water outlet holes of the first drill bit are communicated with the water channel of the first output shaft, and the water outlet holes of the second drill bit are communicated with the water channel of the second output shaft.
4. The method for reinforcing surrounding rock through grouting in a roadway of claim 1, wherein the drill rod is connected with the input shaft, the first output shaft is connected with the first drill bit, and the second output shaft is connected with the second drill bit in a taper mode.
5. The method for reinforcing surrounding rock by grouting in a roadway of claim 1, wherein the diameters of the first drill bit and the second drill bit are the same or different.
6. The method for grouting reinforcement of surrounding rock according to claim 1, wherein,
the input shaft, the first output shaft and the second output shaft are all connected with the gear box through bearings, the input shaft is arranged in the middle of the gear box, and the first output shaft and the second output shaft are arranged on two sides of the input shaft;
the first output shaft and the second output shaft are in matched meshed transmission with the input shaft through a gear set, or the first output shaft and the input shaft are in matched meshed transmission through the gear set, and the second output shaft and the first output shaft are in matched meshed transmission through the gear set.
7. The method of grouting surrounding rock reinforcement in roadway of claim 1, wherein the grouting pipe is an extendable re-grouting pipe comprising:
the grouting pipe comprises a plurality of sections of grouting pipe sections, wherein grouting pipe sections are provided with grouting small holes;
the butt joint unit is connected and arranged between two adjacent grouting pipe sections, and the two adjacent grouting pipe sections are connected in a relatively telescopic sealing manner through the butt joint unit;
the first flexible sleeve is sleeved on the outer wall of the grouting pipe section, and corresponds to the grouting small hole; and
and the second flexible sleeve is sleeved on the outer side of the butt joint unit and the grouting pipe section, and a grout outlet seam is formed between the first flexible sleeve and the second flexible sleeve.
8. The method of grouting reinforcement of a surrounding rock in a roadway of claim 7, wherein the docking unit comprises:
a plurality of pi-shaped iron hooks;
the convex joint is arranged at the lower end of the grouting pipe section at the upper section, and a plurality of hook holes matched with one foot of the n-shaped iron hook are uniformly distributed on the outer wall of the grouting pipe section adjacent to the convex joint in the circumferential direction; and
the female joint is arranged at the upper end of the lower grouting pipe section, the female joint is matched and sleeved with the male joint, and a plurality of sliding hook grooves matched with the other foot of the n-shaped iron hook are uniformly distributed on the periphery of the outer wall of the female joint.
9. The method for grouting surrounding rock reinforcement of a roadway of claim 7, wherein the first flexible sleeve and the second flexible sleeve are each a plurality of rubber films.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201910272082.8A CN109882222B (en) | 2019-04-04 | 2019-04-04 | Small-size double-round hole drilling tool and method for grouting and reinforcing surrounding rock in roadway |
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201910272082.8A CN109882222B (en) | 2019-04-04 | 2019-04-04 | Small-size double-round hole drilling tool and method for grouting and reinforcing surrounding rock in roadway |
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| CN109882222A CN109882222A (en) | 2019-06-14 |
| CN109882222B true CN109882222B (en) | 2023-10-13 |
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Families Citing this family (2)
| Publication number | Priority date | Publication date | Assignee | Title |
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| CN110410009A (en) * | 2019-08-10 | 2019-11-05 | 德威土行孙工程机械（北京）有限公司 | A kind of double output shaft no-dig directional driller power device and matching used drilling rod |
| CN113107537B (en) * | 2021-04-24 | 2023-11-10 | 淮北市平远软岩支护工程技术有限公司 | Distributed grouting technology and method for rock burst countermeasure type roadway |
Citations (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN1408982A (en) * | 2001-09-17 | 2003-04-09 | 石油勘探开发科学研究院钻井工艺研究所 | Method and equipment for drilling large bore well (hole) using small size screw drill tool combination |
| DE10234255A1 (en) * | 2002-06-27 | 2004-01-15 | Friedr. Ischebeck Gmbh | Use of drill injection anchors made from cold-rolled steel having longitudinal channels open in the region of the drill crown for rinsing and injecting cement as flat reinforcements for tunnel roofs |
| KR20090013368A (en) * | 2007-08-01 | 2009-02-05 | 주식회사 공영숏크리트 | Ground enhansing apparatus with anchor rod and method thereof |
| CN202866644U (en) * | 2012-11-09 | 2013-04-10 | 杨振侠 | Way-type drilling unit of roller cone and DTH hammer |
| CN103089274A (en) * | 2013-01-15 | 2013-05-08 | 河南理工大学 | Method capable of repeated grouting and reinforcing surrounding rocks of roadway |
| CN205154000U (en) * | 2015-11-26 | 2016-04-13 | 石家庄四维赛恩特矿业机械股份有限公司 | Can bore heterotype hole's rig |
| CN209724381U (en) * | 2019-04-04 | 2019-12-03 | 河南理工大学 | Small size double circular hole drilling tool |
-
2019
- 2019-04-04 CN CN201910272082.8A patent/CN109882222B/en active Active
Patent Citations (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN1408982A (en) * | 2001-09-17 | 2003-04-09 | 石油勘探开发科学研究院钻井工艺研究所 | Method and equipment for drilling large bore well (hole) using small size screw drill tool combination |
| DE10234255A1 (en) * | 2002-06-27 | 2004-01-15 | Friedr. Ischebeck Gmbh | Use of drill injection anchors made from cold-rolled steel having longitudinal channels open in the region of the drill crown for rinsing and injecting cement as flat reinforcements for tunnel roofs |
| KR20090013368A (en) * | 2007-08-01 | 2009-02-05 | 주식회사 공영숏크리트 | Ground enhansing apparatus with anchor rod and method thereof |
| CN202866644U (en) * | 2012-11-09 | 2013-04-10 | 杨振侠 | Way-type drilling unit of roller cone and DTH hammer |
| CN103089274A (en) * | 2013-01-15 | 2013-05-08 | 河南理工大学 | Method capable of repeated grouting and reinforcing surrounding rocks of roadway |
| CN205154000U (en) * | 2015-11-26 | 2016-04-13 | 石家庄四维赛恩特矿业机械股份有限公司 | Can bore heterotype hole's rig |
| CN209724381U (en) * | 2019-04-04 | 2019-12-03 | 河南理工大学 | Small size double circular hole drilling tool |
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| CN109882222A (en) | 2019-06-14 |
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