Anti-collapse jet grouting drill bit with bi-directional rib wings, grouting consolidation system and method

Abstract

An anti-collapse grouting consolidation system including: a grouting pump; an outer flat drill rod; a drill rig that clamps the outer flat drill rod; a sealing device, sheathed on the outer flat drill rod at the orifice of a drill hole, ensuring the outer flat drill rod is sealed with the orifice of the drill hole; and a jet grouting drill bit with bi-directional rib wings. The grouting pump jets slurry into the drill hole in a static osmotic manner through the jet grouting drill bit. A method of using an anti-collapse grouting consolidation system includes, among other things, injecting quick-setting slurry; sealing an orifice hole of the drill hole by an orifice sealing device; and keeping an anti-collapse jet grouting drill bit with bi-directional rib wings repeatedly moving up and down and rotating at a repair segment to repair the repair segment.

Claims

1. An anti-collapse grouting consolidation system, comprising: a grouting pump; a high-pressure pipeline, connected with the grouting pump; an outer flat drill rod, connected with the high-pressure pipeline; a drill rig, wherein the outer flat drill rod penetrates through an inner through bore of a chuck of the drill rig, and the chuck of the drill rig clamps the outer flat drill rod; an orifice sealing device, configured to be sheathed on the outer flat drill rod at an orifice of a drill hole to ensure that the outer flat drill rod is sealed with the orifice of the drill hole, the orifice sealing device comprising: a pipe protection flange, connected with an orifice pipe; an inner bushing arranged in the orifice pipe and an inner bushing bottom holder, wherein an inner bushing flange is arranged at an upper port of the inner bushing, a lower end of the inner bushing is connected with the inner bushing bottom holder, and the inner bushing bottom holder is disc-shaped and is provided in a center of the inner bushing bottom holder with a circular hole through which the outer flat drill rod passes; a water seal, disposed in the inner bushing, and configured to seal a clearance between the outer flat drill rod and the inner bushing, wherein a water inlet pipe and a high-pressure valve connected with the water inlet pipe are arranged on the water seal; and a gland flange configured to limit expansion of the water seal after water injection, wherein a degree of sealing of the orifice sealing device is controlled by adjusting a quantity of water, injected into the water seal, to adapt to corresponding situations for different sealing requirements of the drill hole; and a jet grouting drill bit with bi-directional rib wings, connected with a one-way valve which is connected with the outer flat drill rod; wherein: the grouting pump is configured to jet quick-setting slurry into the drill hole through a high-pressure hose, the outer flat drill rod and the jet grouting drill bit with bi-directional rib wings successively to realize static osmotic jet grouting, and the drill rig is configured to drive, through the outer flat drill rod, the jet grouting drill bit with bi-directional rib wings to rotate to cut chippings or squeeze the chippings back into a hole wall of the drill hole by means of the jet slurry and rotation of the rib wings so as to repair the hole wall.

2. The anti-collapse grouting consolidation system according to claim 1, wherein the pipe protection flange is in screwed connection with the orifice pipe.

3. The anti-collapse grouting consolidation system according to claim 1, wherein the inner bushing bottom holder, the inner bushing and the inner bushing flange are welded into a whole.

4. The anti-collapse grouting consolidation system according to claim 1, wherein a second sealing gasket is arranged between the pipe protection flange and the inner bushing flange, and a first sealing gasket is arranged between the inner bushing flange and the gland flange; and the pipe protection flange, the inner bushing flange and the gland flange are connected by fastening bolts.

5. The anti-collapse grouting consolidation system according to claim 1, wherein a diameter of the circular hole of the gland flange is 4-6 mm greater than a diameter of the outer flat drill rod; an inner diameter of the inner bushing flange is the same as an inner diameter of the inner bushing; and an outer diameter of the inner bushing flange is greater than an outer diameter of the orifice pipe.

6. The anti-collapse grouting consolidation system according to claim 1, wherein the water seal is made of an elastic wear-resistant material and is in the shape of a ring, an outer diameter of the ring is the same as the inner diameter of the inner bushing, and an inner diameter of the ring is the same as the diameter of the circular hole of the inner bushing bottom holder.

7. The anti-collapse grouting consolidation system according to claim 1, wherein a water inlet valve at the water seal is a high-pressure one and has the same diameter as the water inlet, and a water pipe with the same diameter is connected outside the high-pressure valve.

8. The anti-collapse grouting consolidation system according to claim 1, wherein: the orifice sealing device is composed of drag sleeves, fastening bolts, cotton packing threads and press members, and the drag sleeves are connected with the orifice pipe by screw threads, and the orifice sealing device is configured so that, when sealing the outer flat drill rod with the orifice of the drill hole: the outer flat drill rod passes through the drag sleeves, the cotton packing threads are filled into the drag sleeves, the press members are connected with the drag sleeves together by the fastening bolts, and the cotton packing threads are pressed by the press members and expanded to close the clearance with the outer flat drill rod.

9. A method of using an anti-collapse grouting consolidation system, the method comprising the following steps: step 1: feeding a jet grouting drill bit with bi-directional rib wings connected with an outer flat drill rod into a drill hole to a certain depth, sheathing a sealing device outside the outer flat drill rod, fixing the sealing device at the orifice of the drill hole, and connecting the outer flat drill rod to a high-pressure pipeline and a grouting pump successively after the outer flat drill rod passes through a chuck of a drill rig; step 2: injecting thin cement slurry into the drill hole to flush the drill hole; after the drill hole is full of the thin cement slurry, starting the drill rig to ensure the jet grouting drill bit with bi-directional rib wings rotates, and injecting quick-setting slurry, until the quick-setting slurry overflows between the orifice sealing device and the drill rod; step 3: sealing the orifice of the drill hole by the orifice sealing device, then conveying the rotating drill bit to a repair segment by the outer flat drill rod, stopping injecting the quick-setting slurry after a grouting pressure reaches a set value, and continuing keeping the anti-collapse jet grouting drill bit with bi-directional rib wings repeatedly moving up and down and rotating at the repair segment to repair the repair segment, until the repair process meets a set requirement; step 4: after the repair reaches a setting time, pulling out the outer flat drill rod from the drill hole, so that the jet grouting drill bit with bi-directional rib wings leaves the hole segment that needs grouting reinforcement and drilling repair, and releasing the seal of the sealing device at the orifice; injecting clear water into the drill hole until the clear water overflows between the orifice sealing device and the outer flat drill rod, stopping the drill rig after the drill bit rotates freely in the drill hole, and detaching the outer flat drill rod at the orifice; and step 5: detaching the orifice sealing device, reconnecting the outer flat drill rod, pumping clear water into the drill hole via the grouting pump, starting the drill rig to rotate slowly and pulling up the outer flat drill rod after the clear water returns from the orifice, therefore, the rib wing at the upper end of the jet grouting drill bit with bi-directional rib wings cuts towards an external direction of the drill hole to clear away the solidified quick-setting slurry in the drill hole, and detaching the outer flat drill rod piece by piece, until the jet grouting drill bit with bi-directional rib wings is lifted out of the drill hole, thus ending the operation steps, wherein in step 2, a pump volume of the grouting pump is not more than 100 L/min, and a rotating speed of the outer flat drill rod driven by the drill rig is not more than 150 r/min.

10. The method according to claim 9, wherein a volume of the quick-setting slurry injected into the drill hole is controlled between 1.5 and 2.0 times an internal volume of the drill hole.

11. The method according to claim 9, wherein in step 2, an initial setting time of the quick-setting slurry is controlled at 20-25 min a limit value of the grouting pressure of the grouting pump is controlled at 1.5 MPa; and a pump volume of injecting the quick-setting slurry does not exceed 40 L/min.

12. The method according to claim 9, wherein in step 3, the set value of the grouting pressure is 1.0-1.2 MPa; the rotating speed of the outer flat drill rod driven by the drill rig is not more than 150 r/min; and an up-down moving speed of the outer flat drill rod is not more than 10 m/min.

13. The method according to claim 9, wherein in step 4, a set time reached by the repair is 3 minutes before the quick-setting slurry reaches quick-setting.

14. The method according to claim 9, wherein in step 4, a pump volume of injecting the clear water is not less than 100 L/min; and after the clear water flows out from the orifice and the drill bit rotates freely in the drill hole, the drill rig stops rotating.

15. A method of using an anti-collapse grouting consolidation system, the method comprising the following steps: step 1: feeding a jet grouting drill bit with bi-directional rib wings connected with an outer flat drill rod into a drill hole to a certain depth, sheathing a sealing device outside the outer flat drill rod, fixing the sealing device at an orifice of the drill hole, and connecting the outer flat drill rod to a high-pressure pipeline and a grouting pump successively after the outer flat drill rod passes through a chuck of a drill rig; step 2: injecting thin cement slurry into the drill hole to flush the drill hole; after the drill hole is full of the thin cement slurry, starting the drill rig to ensure the jet grouting drill bit with bi-directional rib wings rotates, and injecting quick-setting slurry, until the quick-setting slurry overflows between the orifice sealing device and the drill rod; step 3: sealing the orifice of the drill hole by the orifice sealing device, then conveying the rotating drill bit to a repair segment by the outer flat drill rod, stopping injecting the quick-setting slurry after the grouting pressure reaches a set value, and continuing keeping the anti-collapse jet grouting drill bit with bi-directional rib wings repeatedly moving up and down and rotating at the repair segment to repair the repair segment, until the repair process meets a set requirement; step 4: after the repair reaches a setting time, pulling out the outer flat drill rod from the drill hole, so that the jet grouting drill bit with bi-directional rib wings leaves a hole segment that needs grouting reinforcement and drilling repair, and releasing a seal of the sealing device at the orifice; injecting clear water into the drill hole until the clear water overflows between the orifice sealing device and the outer flat drill rod, stopping the drill rig after the drill bit rotates freely in the drill hole, and detaching the outer flat drill rod at the orifice; and step 5: detaching the orifice sealing device, reconnecting the outer flat drill rod, pumping clear water into the drill hole via the grouting pump, starting the drill rig to rotate slowly and pulling up the outer flat drill rod after the clear water returns from the orifice, therefore, the rib wing at an upper end of the jet grouting drill bit with bi-directional rib wings cuts towards an external direction of the drill hole to clear away the solidified quick-setting slurry in the drill hole, and detaching the outer flat drill rod piece by piece, until the jet grouting drill bit with bi-directional rib wings is lifted out of the drill hole, thus ending the operation steps, wherein in step 3, the set value of the grouting pressure is 1.0-1.2 MPa; a rotating speed of the outer flat drill rod driven by the drill rig is not more than 150 r/min; and an up-down moving speed of the outer flat drill rod is not more than 10 m/min.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) FIG. 1 is a schematic diagram of an installation structure of an A-type anti-collapse grouting consolidation system;

(2) FIG. 2 is a working principle diagram of the A-type anti-collapse grouting consolidation system;

(3) FIG. 3 is a working principle diagram of drilling towards the external direction of a drill hole after grouting to clear away consolidated slurry in the drill hole;

(4) FIG. 4 is a structure diagram of an A-type orifice sealing device;

(5) FIG. 5 is an assembly structure diagram of the A-type orifice sealing device;

(6) FIG. 6 is a structure diagram of an A-type jet grouting drill bit with bi-directional rib wings;

(7) FIG. 7 is a B-directional view of the A-type jet grouting drill bit with bi-directional rib wings;

(8) FIG. 8 is an A-directional view of the A-type jet grouting drill bit with bi-directional rib wings;

(9) FIG. 9 is a structure diagram of a one-way valve;

(10) FIG. 10 is a structure diagram of a rib wing;

(11) FIG. 11 is an installation structure diagram of a B-type jet grouting drill bit with bi-directional rib wings and an auxiliary device thereof;

(12) FIG. 12 is an assembly structure diagram of a B-type orifice sealing device;

(13) FIG. 13 is a working principle diagram of a B-type water seal;

(14) FIG. 14 is a partial enlarged structure diagram of a connection part of the B-type orifice sealing device;

(15) Reference signs: 1 A-type orifice sealing device, 2 A-type orifice pipe, 3 drill hole, 4 outer flat drill rod, 5 one-way valve, 6 jet grouting drill bit with bi-directional rib wings, 7 hole wall, 8 rock wall, 9 fastening bolt, 10 drag sleeve, 11 cotton packing thread, 12 press member, 13 inner thread screw eye, 14 rib wing, 15 drill body, 16 inner through bore, 17 jet hole, 18 hole wall shrinkage-collapse chipping, 19 forward wing, 20 reverse wing, 21 lateral rib, 22 underground drill rig, 23 high-pressure pipeline, 24 grouting pump, 25 chuck, 26 quick-setting slurry flow direction, 27 up-down direction, 28 rightward rotation, and 29 surrounding rock; 31 B-type orifice sealing device, 32 B-type orifice pipe, 34 water bag, 38 first sealing gasket, 39 gland flange, 40 second sealing gasket, 41 inner bushing flange, 42 inner bushing, 43 inner bushing bottom holder, 44 water seal, 45 fastening bolt, 46 high-pressure valve, 47 pipe protection flange.

DETAILED DESCRIPTION OF THE EMBODIMENTS

(16) The present invention will be further illustrated via the following specific embodiments. It should be noted that the following description is merely for the purpose of illustrating the invention, but not for limiting the invention.

Embodiment 1

(17) A coal mine in Heze, Shandong Province is very complicated in hydro-geological condition. Concentrated and disperse burst water appears at the roof of a main return raising airway of the mine. The water burst area is large, the total amount of burst water is about 25 m.sup.3/h. The burst water comes from fine sandstone (M5), and the normal water pressure of the water-bearing layer of the harnessed region is 3.5 MPa. When the M5 is grouted to plug the drill hole during construction, the shallow surrounding rock 29 is weak and broken, and the wall of the drill hole collapses seriously, so that drilling accidents happen frequently; the conventional method of grouting the whole hole for reinforcement via an orifice pipe is hardly effective; cement slurry is grouted, and the setting time of the cement slurry is 72 hours according to the design, so the setting waiting time is long, and the phenomena of collapse and chipping still occur sometimes during re-drilling in the drill hole after grouting reinforcement. The project progress is seriously affected. Later, an anti-collapse grouting consolidation device was researched and applied to achieve success of a one-time grouting consolidation. The accident rate and the closure time are greatly reduced, and the effect is significant.

(18) The jet grouting drill bit 6 with bi-directional rib wings shown in FIG. 6 is mainly composed of an inner thread screw eye 13 matched and connected with a one-way valve 5, rib wings 14, a drill bit body 15, an inner through bore 16, jet holes 17 and the like. FIG. 7 and FIG. 8 show the projections of the two ends of the jet grouting drill bit 6 with bi-directional rib wings.

(19) As shown in FIG. 10, the rib wing is arranged laterally of the drill bit body along the longitudinal direction of the drill bit. And the rib wings include a forward wing 19 arranged at the front end of the drill bit, a reverse wing 20 arranged at the rear end of the drill bit, and a side wing 21 connecting the forward wing 19 and the reverse wing 20. The included angle between the forward wing 19 and the side wing 21, as well as the included angle between the reverse wing 20 and the side wing 21 are obtuse angles.

(20) The rib wings are connected with the drill bit body fixedly or movably. The conventional connection forms fall into the protection scope of the present invention.

(21) The drill bit here may be specifically shaped to have a conical body at the front end, as shown in FIG. 1, or a horizontal end at the front end of the drill bit body, see FIG. 11, on condition that the drill bit includes the forward wing 19, the reverse wing 20 and the side wing 21.

(22) The technical requirement of the manufacturing process for the jet grouting drill bit 6 with bi-directional rib wings in the anti-collapse grouting consolidation system is shown as follows: the drill bit body 15 is made of geological round steel, with the steel grade not lower than DZ45. The diameter of the inner through bore 16 is 28 mm, and the inner thread screw eye 13 is machined into the same inner buckle type as the screw thread of an outer flat drill rod 4 and is right-handed; there are three rib wings 14 with the thicknesses of 20 mm, and the side edge heights of the rib wings are determined by the difference between the diameter of a drill hole 3 and the diameter of the drill bit body 15, The rib wings 14 are uniformly distributed 120 degrees on the cross section of the drill bit body 15 and welded together with the drill bit body 15, and hard alloy fragments are welded on the rib wings 14. The hard alloy fragments may also be fixed on the rib wings by other ways, as long as the bonding parts can meet certain strength.

(23) The outer edges of the three rib wings are required to be on the same cylindrical side surface, and it is better that the cylindrical axis is superposed with the axis of the drill bit body 15.

(24) In the case that the cylindrical axis slightly deviates from the axis of the drill bit body or the outer edges of the rib wings are not on the same cylindrical surface, it still falls into the protection scope of the present invention as long as it can realize the function.

(25) The three rib wings are triangular on the upper and lower end faces of the drill bit body 15, and are combined into a triangular pyramid. The drill bit body 15 is machined with totally nine jet holes 17 having the diameters of 10 mm. The buckle type of the one-way valve 5 is same as that of the outer flat drill rod 4, the lower end is an outer buckle and is connected with the drill bit body 15 via the inner thread screw eye 13, and the upper end is of an inner buckle and is connected with the outer flat drill rod 4. The diameters of both the outer flat drill rod and the one-way valve are 50 mm. The structure and connection of the one-way valve 5 is shown in FIG. 9.

(26) The specific dimensions of the components of the drill bit body herein are of a preferred embodiment, but the protection scope is not limited to the specific values mentioned here.

(27) The number of the rib wings is not limited to three, may be four or other number. In the case of four rib wings, the rib wings 14 are uniformly distributed at 90 degrees on the cross section of the drill bit body.

(28) The included angle between the forward wing 19 and the side wing 21, and also the included angle between the reverse wing 20 and the side wing 21 are preferably 135°, however, the actual included angles may be any degrees within the obtuse angle range.

(29) An anti-collapse grouting consolidation system is formed by successively connecting the jet grouting drill bit 6 with bi-directional rib wings, the one-way valve 5, the outer flat drill rod 4, an A-type orifice sealing device 1, a chuck 25, an underground drill rig 22, a high-pressure pipeline 23 and a grouting pump 24 from bottom to top.

(30) The anti-collapse grouting consolidation system is installed on the premise that an A-type orifice pipe 2 is installed at the drill hole 3 and the cementing quality of the A-type orifice pipe 2 and the hole wall 7 is good. As shown in FIG. 4 and FIG. 5, the A-type orifice sealing device 1 is mainly composed of drag sleeves 10, fastening bolts 9, cotton packing threads 11 and press members 12. The drag sleeves 10 are connected with the A-type orifice pipe 2 by screw threads. After the outer flat drill rod 4 passes through the drag sleeves 10, the cotton packing threads 11 are filled into the drag sleeves 10, the press members 12 are installed, the press members 12 are connected with the drag sleeves 10 together by the fastening bolts 9, the fastening bolts 9 are screwed, and the cotton packing threads 11 are pressed by the press members 12. The cotton packing threads 11 expand to close the clearance with the outer flat drill rod 4.

(31) The connection operation steps of all parts of the anti-collapse grouting consolidation system are as follows:

(32) Step 1: connecting the jet grouting drill bit 6 with bi-directional rib wings, the one-way valve 5 and the outer flat drill rod 4 successively from bottom to top.

(33) Step 2: putting the connected jet grouting drill bit 6 with bi-directional rib wings, one-way valve 5 and outer flat drill rod 4 into the drilled rod 3. Before they are put into the drill hole 3, the A-type orifice sealing device penetrates through the upper end of the outer flat drill rod 4, and then a hydraulic chuck of the underground drill rig 22 penetrates through the outer flat drill rod 4 and is tightened.

(34) Step 3: installing the A-type orifice sealing device 1. The A-type orifice sealing device 1 and the A-type orifice pipe 2 are tightened, then the cotton packing threads 11 are filled into the drag sleeves 10 successively, the press members 12 are installed, and the fastening bolts 9 are connected (without compression, with gaps retained).

(35) Step 4: slowly lowering the outer flat drill rod 4 held by the hydraulic chuck of the underground drill rig 22 into the drill hole 3.

(36) Step 5: connecting the outer flat drill rod piece by piece for lengthening, and putting the jet grouting drill bit with bi-directional rib wings into the hole through the outer flat drill rod by using the hydraulic chuck of the underground drill rig 22 to reach the outer end of the hole segment that needs grouting reinforcement and drilling repair.

(37) Step 6: connecting the outer flat drill rod 4, the high-pressure pipeline 23 and the grouting pump 24.

(38) A using method of the anti-collapse grouting consolidation system shown in FIG. 2 includes the following steps:

(39) Step 1: auxiliary devices for the anti-collapse jet grouting drill bit with bi-directional rib wings are installed.

(40) Step 2: the grouting pump 24 is started to pump thin cement slurry into the drill hole 3 to flush the drill hole 3; and the cement slurry flows out from the gaps between the drag sleeves 10 and the outer flat drill rod 4.

(41) Step 3: the underground drill rig 22 is started, and the outer flat drill rod 4 drives the jet grouting drill bit with bi-directional rib wings to rotate.

(42) Step 4: the thin cement slurry is changed into quick-setting slurry, and the quick-setting slurry is injected into the drill hole 3 in flow direction 26 through the high-pressure hose 23, the outer flat drill rod 4 and the jet holes 17 of the jet grouting drill bit with bi-directional rib wings.

(43) Step 5: after the quick-setting slurry flows out of the gaps between the drag sleeves 10 and the outer flat drill rod 4, the fastening bolts 9 are tightened, the press members 12 press the cotton packing threads 11, and the cotton packing threads 11 expand to close the clearance with the outer flat drill rod 4.

(44) Step 6: slurry grouting is continued, until the grouting amount is 1.5-2.0 times the internal volume of the drill hole 3. Meanwhile, the underground drill rig 22 continues to drive the jet grouting drill bit 6 with bi-directional rib wings to rotate rightward 28, the outer flat drill rod 4 is fed into the drill hole 3, so that the jet grouting drill bit 6 with bi-directional rib wings slowly penetrates through the hole segment that needs grouting reinforcement and drilling repair; the rib wings 14 on the drill bit cut hole wall shrinkage-collapse chippings 18, or squeeze the chippings back into the hole wall 7 to repair the instable hole wall 7; and the hydraulic chuck of the drill rig clamps the outer flat drill rod 4 should not stop rotating, and the jet grouting drill bit 6 with bi-directional rib wings moves up and down 27 repeatedly in the hole segment.

(45) Step 7: as shown in FIG. 3, from the start of the grouting pump 24 to suck the slurry to 3 minutes before initial setting of the quick-setting slurry, the hydraulic chuck of the drill rig slowly rotates, and the outer flat drill rod 4 is withdrawn from the drill hole 3, so that the jet grouting drill bit 6 with bi-directional rib wings leaves the hole segment that needs grouting reinforcement and drilling repair. The withdrawal of the outer flat drill rod 4 is stopped after leaving, but the outer flat drill rod 4 should be rotated; the fastening bolts 9 are unscrewed to release the seal between the drag sleeves 10 and the outer flat drill rod 4, and clear water is pumped into the drill hole 3 by increasing the volume of the grouting pump 24, until the clear water returns between the A-type orifice sealing device 1 and the outer flat drill rod 4.

(46) Step 8: rotation of the outer flat drill rod 4 is continued, while clear water is continuously pumped into the drill hole 3, until the outer flat drill rod 4 and the jet grouting drill bit 6 with bi-directional rib wings rotate freely in the drill hole 3.

(47) Step 9: the grouting pump 24 is stopped, the hydraulic chuck of the underground drill rig 22 stops driving the outer flat drill rod 4 to rotate up and down, the outer flat drill rod 4 is detached at the orifice, and the A-type orifice sealing device 1 is detached.

(48) Step 10: the outer flat drill rod 4 is reconnected, the grouting pump 24 is started, clear water is pumped into the drill hole 3 via the high-pressure hose 23, the outer flat drill rod 4 and the jet grouting drill bit 6 with bi-directional rib wings respectively, the drill rig is started to rotate slowly after the clear water returns from the orifice, and the outer flat drill rod 4 is pulled out, so that the rib wing at the upper end of the jet grouting drill bit 6 with bi-directional rib wings clears away the solidified quick-setting slurry outside the jet grouting drill bit 6 with bi-directional rib wings in the drill hole 3; and the outer flat drill rod 4 is detached piece by piece, until the jet grouting drill bit 6 with bi-directional rib wings is lifted out of the drill hole 3.

(49) Step 11: the outer flat drill rod 4, the one-way valve 5 and the jet grouting drill bit with bi-directional rib wings are detached respectively. The operation steps are ended.

(50) The technical requirements for safe operation are as follows:

(51) In step 1, all devices must be inspected before connection to ensure normal operation; a thread compound must be used between the outer flat drill rod pieces, between the outer flat drill rod and the one-way valve, and between the one-way valve and the rib wing drill bit, and the components must be tightened and should not be subject to leakage at the threads.

(52) In step 2, the density of the cement slurry is controlled at 1.2-1.4 g/cm.sup.3, and the volume of the grouting pump is not more than 100 L/min.

(53) In step 3, the rotating speed of the outer flat drill rod 4 driven by the underground drill rig 22 is not more than 150 r/min; and after the A-type orifice sealing device 1 is sealed with the outer flat drill rod 4, no leakage is required when the grouting pressure in the drill hole 3 is 1.5 MPa.

(54) In step 4, the initial setting time of the quick-setting slurry is controlled at about 20-25 min, and must be tested before grouting; the limit value of the grouting pressure of the grouting pump 24 is controlled at 1.5 MPa; the pump volume of injecting the quick-setting slurry should not exceed 40 L/min; and the volume of the quick-setting slurry injected into the drill hole 3 is controlled between 1.5 and 2.0 times the internal volume of the drill hole 3. The grouting pressure is controlled at 1.0-1.2 MPa.

(55) In step 5, after the press members 12 press tightly, the tightness between the cotton packing threads 11 and the outer flat drill rod 4 ensures no leakage when the grouting pressure is 1.5 MPa.

(56) In step 6, the rotating speed of the outer flat drill rod 4 driven by the underground drill rig 22 is not more than 150 r/min. The up-down moving speed of the outer flat drill rod does not exceed 10 m/min.

(57) In step 7, the pump volume of injecting the clear water is not less than 100 L/min.

(58) The outer flat drill rod 4 can be stopped from rotating when the fastening bolts 9 are detached to release the seal between the drag sleeves 10 and the outer flat drill rod 4 in step 7, while in all other processes, the outer flat drill rod 4 should not be stopped or reversed, and pumping of the clear water should not be stopped.

(59) The following safety attentions are emphasized in use of the anti-collapse grouting consolidation system:

(60) (1) All parts of the outer flat drill rod 4, the one-way valve 5 and the jet grouting drill bit 6 with bi-directional rib wings must be connected firmly, and the phenomena of thread loosening and even thread-off at the connected positions should be avoided; (2) the one-way valve should not be reversed; (3) continuous supply and normal circulation of flushing fluid (or quick-setting slurry) in the hole must be ensured when the non-lift jet grouting drill bit 6 with bi-directional rib wings rotates and moves in the drill hole 3; (4) the entire operation, particularly the grouting process must ensure that the anti-collapse grouting consolidation device rotates and moves continuously and should not stop halfway; (5) the clearance between the orifice sealing device 1 and the outer flat drill rod 4 is not sealed to ensure that the outer flat drill rod 4 rotates and moves freely, and is sealed to ensure no leakage when the grouting pressure in the drill hole 3 reaches 1.5 MPa; (6) the right-hand rotation of the jet grouting drill bit 6 with bi-directional rib wings must be ensured throughout the operation to prevent left-hand rotation; (7) before the operation, the performance of the injected quick-setting slurry must be tested to master the initial setting time and the consolidation strength thereof accurately, otherwise, it shall not be used; and (8) the sealing quality between the orifice sealing device 1 and the outer flat drill rod also needs to be tested in advance to ensure no leakage during operation.

Embodiment 2

(61) As shown in FIGS. 11-14, a B-type orifice sealing device 31 adopts the following structure, including: a pipe protection flange 47 in screwed connection with a B-type orifice pipe 32; an inner bushing 42 arranged in the B-type orifice pipe 32 and an inner bushing bottom holder 43, wherein an inner bushing flange 41 is arranged at the upper port of the inner bushing 42, the lower end of the inner bushing 42 is connected with the inner bushing bottom holder 43, and the inner bushing bottom holder 43 is disc-shaped and is provided in the center with a circular hole through which the outer flat drill rod 4 passes; a water bag 34 disposed in the inner bushing, after being filled with water and expanded, the water bag 34 forms a water seal 44 to seal the clearance between the outer flat drill rod 4 and the inner bushing 42, and a water inlet pipe and a high-pressure valve 46 connected with the water inlet pipe are arranged on the water seal 44;

(62) A gland flange 39 is used for limiting expansion of the water weal 44 after water injection; wherein the sealing and the sealing degree of the orifice sealing device 1 are controlled by adjusting the water injection quantity of the water seal 44 to adapt to corresponding situations for different sealing requirements of the drill hole 3.

(63) The inner bushing bottom holder 43, the inner bushing 42 and the inner bushing flange 41 are welded into a whole.

(64) A second sealing gasket 40 is arranged between the pipe protection flange 47 and the inner bushing flange 41, and a first sealing gasket 38 is arranged between the inner bushing flange 41 and the gland flange 39.

(65) The pipe protection flange 47, the inner bushing flange 41 and the gland flange 39 are connected by fastening bolts 45.

(66) The diameter of the circular hole of the inner bushing bottom holder 43 is 4-6 mm greater than that of the outer flat drill rod 4.

(67) The inner diameter of the inner bushing flange 41 is the same as that of the inner bushing 42, and the outer diameter of the inner bushing flange 41 is greater than that of the orifice pipe 32 and same as that of the pipe protection flange 47.

(68) The water seal 44 is made of an elastic wear-resistant material and is in the shape of a ring, the outer diameter of the ring is the same as the inner diameter of the inner bushing 42, and the inner diameter of the ring is the same as the diameter of the circular hole of the inner bushing bottom holder 43.

(69) The water inlet valve at the water seal 44 is a high-pressure valve 46 and has the same diameter as the water inlet, and a water pipe having the same diameter is connected outside the high-pressure valve 46.

(70) Although the specific embodiments of the present invention are described above in combination with the accompanying drawings, the protection scope of the present invention is not limited thereto. It should be understood by those skilled in the art that various modifications or variations could be made by those skilled in the art based on the technical solution of the present invention without any creative effort, and these modifications or variations shall fall into the protection scope of the present invention.