Hole collapse prevention device for soft broken surrounding rock TBM tunnel anchor rod drilling and construction method

Abstract

The invention discloses a soft broken surrounding rock TBM tunnel anchor rod drilling hole collapse prevention device and a construction method, and relates to the technical field of tunnel anchor rods. The device comprises an anchor rod drilling machine, an anchor rod drilling rod, an anchor rod drilling bit and a steel floral tube; the lower end of the anchor rod drill rod is fixedly connected to the drill shank of the anchor rod drilling machine through threads, the anchor rod drill bit is fixedly connected to the upper end of the anchor rod drill rod through threads, the steel floral tube is arranged on the anchor rod drill rod in a sleeving mode, and a detachable mechanism is arranged at the end, close to the steel floral tube, of the anchor rod drilling machine. In the drilling process, the steel floral tube moves along with an anchor rod drill bit, hole collapse, drill jamming risks and drill retreating difficulty caused by hole wall chipping and excessive deformation in the drilling process are effectively prevented through the steel floral tube, the anchor rod construction hole forming rate and the anchor rod construction efficiency are improved, deformation of soft and broken surrounding rock and development of a plastic zone can be limited in time, and the construction period is shortened. And the surrounding rock stability and the TBM construction safety are improved.

Description

Technical Field

[0001] The invention relates to the technical field of tunnel anchor rods, and in particular to a device for preventing the collapse of anchor rods in a soft and broken surrounding rock TBM tunnel and a construction method. Background Art

[0002] As my country's tunnel construction gradually develops towards the western mountainous areas, rock tunneling machines (TBMs) will inevitably encounter adverse geological phenomena such as soft and broken rock during the excavation process; and anchor rods, as one of the most effective support measures to reinforce surrounding rock and limit surrounding rock deformation, have been widely used in tunnels and underground projects.

[0003] However, the relatively broken rock mass is prone to hole collapse and drill jam, which significantly reduces the drilling rate and construction efficiency. In the process, the tunnel stress of the weak and broken rock mass is continuously released, and the displacement of the surrounding rock continues to increase, which is prone to the problem of surrounding rock instability due to untimely support. In addition, since the anchor rod is a flexible support with poor shear resistance, it is easy to be sheared when the surrounding rock deformation is too large.

[0004] In view of the above problems, an improved anti-collapse hole device and construction method for anchor drilling in soft and broken surrounding rock TBM tunnel is designed. Summary of the invention

[0005] The object of the present invention is to provide a device and a construction method for preventing the collapse of anchor holes in a TBM tunnel with soft and broken surrounding rock, so as to solve the problems raised in the above-mentioned background technology.

[0006] To achieve the above object, the present invention provides the following technical solutions: The invention discloses a device for preventing the collapse of anchor holes in a TBM tunnel with soft and broken surrounding rock, comprising an anchor drill, an anchor drill rod, an anchor drill bit and a steel pipe. The output end of the anchor drill is provided with an anchor drill tail. The side wall of the anchor drill tail is provided with an external thread. The lower end and the upper end of the inner wall of the anchor drill rod are both provided with an internal thread. The lower end of the anchor drill rod is fixedly connected to the anchor drill tail by a thread. The anchor drill bit is fixedly connected to the upper end of the anchor drill rod by a thread. The steel flower pipe is sleeved on the anchor drill rod, the anchor drill bit and the anchor drill rod can move inside the steel flower pipe, a plurality of grouting slurry overflow holes are opened on the side wall of the steel flower pipe, the grouting slurry overflow holes are used to enable the grouting slurry to penetrate into the soft and broken surrounding rock when the anchor is grouting, so as to improve the strength and stability of the surrounding rock around the anchor drill hole, and a detachable mechanism for detachably connecting the steel flower pipe is arranged at one end of the anchor drill rig close to the steel flower pipe.

[0007] As a further solution of the present invention: the anchor drill bit is formed by two semi-cylindrical bodies connected as one body, the two semi-cylindrical bodies have the same diameter, and there is a high-pressure wind and water nozzle in the middle. The radius of the anchor drill rod is smaller than the diameter of the two semi-cylindrical bodies on the anchor drill bit.

[0008] As a further solution of the present invention: The detachable mechanism includes the front shell of the rock bolt drill and the adapter. The front shell of the rock bolt drill is sleeved on the tail of the rock bolt of the rock bolt drill. The front shell of the rock bolt drill is fixed on the shell of the rock bolt drill. A steel flower pipe fixing member is installed at the upper end of the front shell of the rock bolt drill. A casing is rotatably connected to the upper end of the steel flower pipe fixing member. The inner wall of the casing is connected to half of the adapter by a thread. The lower end of the steel flower pipe is connected to half of the adapter by a thread. A cuttings baffle for blocking the gap between the steel flower pipe and the rock bolt drill rod is provided at the upper end of the adapter. The steel flower pipe fixing member, the casing, the adapter, and the cuttings baffle are all rotatably sleeved on the side wall of the rock bolt drill rod. A plurality of multi-channel cuttings discharge ports are provided on the side wall of the steel flower pipe close to the rock bolt drill.

[0009] As a further solution of the present invention: The middle of the steel flower pipe fixing member is thin and both ends are thick. The inner diameter of the adapter is larger than the diameter of the rock bolt drill rod.

[0010] As a further solution of the present invention: The inner diameter of the cuttings baffle is the same as the diameter of the rock bolt drill rod. The outer diameter of the cuttings baffle is the same as the inner diameter of the steel flower pipe. The diameter of the steel flower pipe is 2-4 mm smaller than the drilling diameter.

[0011] The construction method of the anti-collapse hole device for the rock bolt drilling in the TBM tunnel of soft and broken surrounding rock includes the following steps: Step 1: Before the TBM advances to the section of soft and broken surrounding rock, sleeve the steel flower pipe on the rock bolt drill rod and the rock bolt bit, and then connect the lower end of the steel flower pipe to half of the adapter by a thread.

[0012] Step 2: Start drilling. Start the rock bolt drill. The rock bolt drill drives the rock bolt drill rod to rotate. The rock bolt drill rod drives the rock bolt bit to rotate. The rock bolt bit starts drilling. The cuttings drilled out are conveyed to the multi-channel cuttings discharge ports through the gap between the steel flower pipe and the rock bolt drill rod, and then discharged through the multi-channel cuttings discharge ports.

[0013] Step 3: After the drilling is completed, rotate the casing. The casing drives the adapter to rotate, so that the adapter is separated from the steel flower pipe. Then, pull out the rock bolt drill rod and the rock bolt bit from the steel flower pipe, and only leave the steel flower pipe inside the drill hole.

[0014] Step 4: After the rock bolt drill rod and the rock bolt bit are removed, fix the steel flower pipe in the surrounding rock through the steel flower pipe backing plate to prevent it from sliding out of the rock bolt hole.

[0015] Step 5: Insert the rock bolt into the inside of the steel flower pipe, and set a rock bolt backing plate at one end of the rock bolt close to the steel flower pipe backing plate. Then, inject grouting slurry into the steel flower pipe. The slurry seeps into the surrounding rock and cements the broken surrounding rock into blocks, thereby forming a high-strength pipe-anchor combined support structure, improving the shear resistance and support strength of the rock bolt.

[0016] Compared with the prior art, the beneficial effects of the present invention are as follows: When drilling in the present invention, the steel flower pipe moves together with the anchor rod bit. The steel flower pipe effectively prevents the risks of hole wall collapse, drill pipe jamming, and difficult drill pipe withdrawal caused by excessive block falling and deformation of the hole wall during the drilling process, improves the hole formation rate and construction efficiency of the anchor rod, can timely limit the deformation of soft and broken surrounding rock and the development of the plastic zone, and improves the stability of the surrounding rock and the safety of TBM construction.

[0017] After the drilling is completed in the present invention, the steel flower pipe is disassembled and left in the drill hole, and then an anchor rod is inserted into the steel flower pipe, thereby forming a pipe-anchor combined support structure, preventing problems such as the anchor rod being pulled and sheared due to excessive deformation of the surrounding rock, and improving the support strength of the anchor rod and the shear resistance of the anchor rod.

[0018] At the same time, the slurry overflow holes on the steel flower pipe can make the slurry seep into the internal part of the surrounding rock, cement the broken surrounding rock into blocks, improve the strength of the surrounding rock around the anchor rod, and effectively improve the stability of the soft and broken surrounding rock. Description of the Drawings

[0019] Figure 1 It is a schematic structural diagram of the present invention.

[0020] Figure 2 It is a schematic structural diagram of the anchor rod drill pipe in the present invention.

[0021] Figure 3 It is a schematic structural diagram of the shank end of the anchor rod drill in the present invention.

[0022] Figure 4 It is a schematic structural diagram of the anchor rod bit in the present invention.

[0023] Figure 5 It is a schematic structural diagram of the detachable mechanism in the present invention.

[0024] Figure 6 It is a schematic structural diagram of the pipe-anchor combined support structure in the present invention.

[0025] Wherein: 1. Anchor rod drill; 2. Anchor rod drill pipe; 3. Anchor rod bit; 4. Steel flower pipe fixing piece; 5. Sleeve; 6. Multi-channel cuttings discharge port; 7. Steel flower pipe; 8. Grouting slurry overflow hole; 9. Shank end of the anchor rod drill; 10. Front shell of the anchor rod drill; 11. Adapter; 12. Cuttings baffle; 13. Anchor rod; 14. Grouting slurry; 15. Steel flower pipe backing plate; 16. Anchor rod backing plate. Detailed Embodiments

[0026] Next, the technical solutions in the embodiments of the present invention will be clearly and completely described in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present invention.

[0027] Please refer to Figures 1-6 , in the embodiment of the present invention, a device for preventing hole collapse in the TBM tunnel bolt drilling of soft and fractured surrounding rock includes a bolt drill 1, a bolt drill pipe 2, a bolt drill bit 3, and a perforated steel pipe 7. An output end of the bolt drill 1 is provided with a shank 9 of the bolt drill. An external thread is provided on a side wall of the shank 9 of the bolt drill. Internal threads are provided at both a lower end and an upper end of an inner wall of the bolt drill pipe 2. The lower end of the bolt drill pipe 2 is fixedly connected to the shank 9 of the bolt drill by a thread. The bolt drill bit 3 is fixedly connected to the upper end of the bolt drill pipe 2 by a thread. The perforated steel pipe 7 is sleeved on the bolt drill pipe 2. Both the bolt drill bit 3 and the bolt drill pipe 2 can move inside the perforated steel pipe 7. A plurality of grouting slurry overflow holes 8 are formed in a side wall of the perforated steel pipe 7. The grouting slurry overflow holes 8 are used for enabling the grouting slurry 14 to penetrate into the soft and fractured surrounding rock when the bolt 13 is constructed by grouting, so as to improve the strength and stability of the surrounding rock around the bolt hole. A detachable mechanism for detachably connecting the perforated steel pipe 7 is provided at one end of the bolt drill 1 close to the perforated steel pipe 7.

[0028] During drilling, the perforated steel pipe 7 can effectively prevent the risks of hole wall block falling, deformation and other hole collapse problems. After drilling is completed, only the drill needs to be withdrawn, and the perforated steel pipe 7 remains inside the surrounding rock as a part of the primary support, and a pipe - bolt combined support structure is formed after the bolt 13 is constructed, so as to improve the shear resistance and support strength of the bolt 13.

[0029] The bolt drill bit 3 is integrally connected by two semi - cylindrical bodies with the same diameter and a high - pressure water and air nozzle in the middle.

[0030] The radius of the bolt drill pipe 2 is smaller than the radius of the two semi - cylindrical bodies on the bolt drill bit 3.

[0031] The detachable mechanism includes the front shell 10 of the rock bolt drill and the adapter 11. The front shell 10 of the rock bolt drill is sleeved on the tail 9 of the rock bolt of the rock bolt drill. The front shell 10 of the rock bolt drill is fixed on the shell of the rock bolt drill 1. A steel flower pipe fixing member 4 is installed at the upper end of the front shell 10 of the rock bolt drill. A sleeve 5 is rotatably connected to the upper end of the steel flower pipe fixing member 4. The inner wall of the sleeve 5 is connected to half of the adapter 11 by threads. The lower end of the steel flower pipe 7 is connected to half of the adapter 11 by threads. A cuttings baffle 12 for blocking the gap between the steel flower pipe 7 and the rock bolt drill rod 2 is provided at the upper end of the adapter 11. The steel flower pipe fixing member 4, the sleeve 5, the adapter 11, and the cuttings baffle 12 are all rotatably sleeved on the side wall of the rock bolt drill rod 2. A plurality of multi-channel cuttings discharge ports 6 are provided on the side wall of the steel flower pipe 7 close to the rock bolt drill 1.

[0032] The steel flower pipe fixing member 4 is thin in the middle and thick at both ends. The inner diameter of the adapter 11 is larger than the diameter of the rock bolt drill rod 2. The inner diameter of the cuttings baffle 12 is the same as the diameter of the rock bolt drill rod 2. The outer diameter of the cuttings baffle 12 is the same as the inner diameter of the steel flower pipe 7. The diameter of the steel flower pipe 7 is 2-4 mm smaller than the drilling diameter.

[0033] The construction method of the anti-collapse hole device for the rock bolt drilling of the TBM tunnel in soft and broken surrounding rock includes the following steps: Step 1: Before the TBM advances to the soft and broken surrounding rock section, sleeve the steel flower pipe 7 on the rock bolt drill rod 2 and the rock bolt bit 3, and then connect the lower end of the steel flower pipe 7 to half of the adapter 11 by threads.

[0034] Step 2: Start drilling. Start the rock bolt drill 1. The rock bolt drill 1 drives the rock bolt drill rod 2 to rotate. The rock bolt drill rod 2 drives the rock bolt bit 3 to rotate. The rock bolt bit 3 starts to drill. The cuttings drilled out are transported to the multi-channel cuttings discharge port 6 through the gap between the steel flower pipe 7 and the rock bolt drill rod 2, and then discharged through the multi-channel cuttings discharge port 6.

[0035] Step 3: After the drilling is completed, rotate the sleeve 5. The sleeve 5 drives the adapter 11 to rotate, so that the adapter 11 is separated from the steel flower pipe 7. Then, pull out the rock bolt drill rod 2 and the rock bolt bit 3 from the steel flower pipe 7, and only leave the steel flower pipe 7 inside the drill hole.

[0036] Step 4: After the rock bolt drill rod 2 and the rock bolt bit 3 are removed, fix the steel flower pipe 7 in the surrounding rock through the steel flower pipe backing plate 15 to prevent it from slipping out of the rock bolt hole.

[0037] Step Five: Insert the bolt 13 into the inside of the perforated steel pipe 7, and set a bolt backing plate 16 at one end of the bolt 13 close to the perforated steel pipe backing plate 15. Then, inject grouting slurry 14 into the inside of the perforated steel pipe 7. The slurry seeps into the surrounding rock and cements the broken surrounding rock into blocks, thereby forming a high-strength pipe-anchor combined support structure, which improves the shear resistance and support strength of the bolt.

[0038] For those skilled in the art, it is obvious that the present invention is not limited to the details of the above-described exemplary embodiments, and without departing from the spirit or basic characteristics of the present invention, the present invention can be implemented in other specific forms.

Claims

1. A device for preventing the collapse of anchor holes in a TBM tunnel with weak and broken surrounding rock, comprising an anchor drill (1), an anchor drill rod (2), an anchor drill bit (3) and a steel pipe (7), wherein an output end of the anchor drill (1) is provided with an anchor drill tail (9), a side wall of the anchor drill tail (9) is provided with an external thread, an inner wall lower end and an inner wall upper end of the anchor drill rod (2) are both provided with an internal thread, the lower end of the anchor drill rod (2) is fixedly connected to the anchor drill tail (9) by a thread, and the anchor drill bit (3) is fixedly connected to the upper end of the anchor drill rod (2) by a thread, wherein: The steel flower tube (7) is sleeved on the anchor drill rod (2); the anchor drill bit (3) and the anchor drill rod (2) are both movable inside the steel flower tube (7); a plurality of grouting slurry overflow holes (8) are provided on the side wall of the steel flower tube (7); and a detachable mechanism for detachably connecting the steel flower tube (7) is provided at one end of the anchor drill rig (1) close to the steel flower tube (7).

2. The anti-collapse hole device for anchor drilling in soft and broken surrounding rock TBM tunnel according to claim 1 is characterized in that: The anchor drill bit (3) is formed by two semi-cylindrical bodies connected as one body, the two semi-cylindrical bodies have the same diameter and a high-pressure wind and water nozzle is provided in the middle, and the radius of the anchor drill rod (2) is smaller than the radius of the two semi-cylindrical bodies on the anchor drill bit (3).

3. The anti-collapse hole device for anchor drilling in soft and broken surrounding rock TBM tunnel according to claim 1 is characterized in that: The detachable mechanism comprises a front shell (10) of the anchor drill and an adapter (11). The front shell (10) of the anchor drill is sleeved on the shank (9) of the anchor drill. The front shell (10) of the anchor drill is fixed on the housing of the anchor drill (1). A steel flower pipe fixing part (4) is installed on the upper end of the front shell (10). A sleeve (5) is rotatably connected to the upper end of the steel flower pipe fixing part (4). The inner wall of the sleeve (5) is connected to the half adapter (11) via a thread. The lower end of the tube (7) is connected to a half adapter (11) through a thread, and the upper end of the adapter (11) is provided with a rock chip baffle (12) for blocking the gap between the steel flower tube (7) and the anchor drill rod (2). The steel flower tube fixing part (4), the casing (5), the adapter (11), and the rock chip baffle (12) are all rotatably sleeved on the side wall of the anchor drill rod (2), and a plurality of multi-channel rock chip discharge ports (6) are opened on the side wall of the steel flower tube (7) close to the anchor drill rig (1).

4. The anti-collapse hole device for anchor drilling in soft and broken surrounding rock TBM tunnel according to claim 3 is characterized in that: The steel flower pipe fixing piece (4) is thin in the middle and thick at both ends, and the inner diameter of the adapter (11) is larger than the diameter of the anchor rod drill rod (2).

5. The anti-collapse hole device for anchor drilling in soft and broken surrounding rock TBM tunnel according to claim 3 is characterized in that: The inner diameter of the rock debris baffle (12) is the same as the diameter of the anchor drill rod (2), the outer diameter of the rock debris baffle (12) is the same as the inner diameter of the steel flower tube (7), and the diameter of the steel flower tube (7) is 2-4 mm smaller than the diameter of the drill hole.

6. The construction method of the soft and broken surrounding rock TBM tunnel anchor drilling and anti-collapse hole device according to any one of claims 1 to 5, characterized in that: The following steps are involved: Step 1: Before the TBM excavates to the soft and broken surrounding rock section, the steel flower tube (7) is put on the anchor drill rod (2) and the anchor drill bit (3), and then the lower end of the steel flower tube (7) is connected to the half adapter (11) through a thread; Step 2: Drilling begins, the anchor drill rig (1) is started, the anchor drill rig (1) drives the anchor drill rod (2) to rotate, the anchor drill rod (2) drives the anchor drill bit (3) to rotate, the anchor drill bit (3) starts drilling, and the drilled rock cuttings are transported to the multi-channel rock cuttings discharge port (6) through the gap between the steel flower tube (7) and the anchor drill rod (2), and then discharged through the multi-channel rock cuttings discharge port (6); Step 3: After the drilling is completed, the casing (5) is rotated, and the casing (5) drives the adapter (11) to rotate, so that the adapter (11) is separated from the steel flower tube (7), and then the anchor drill rod (2) and the anchor drill bit (3) are pulled out of the steel flower tube (7), leaving only the steel flower tube (7) inside the drill hole; Step 4: After the anchor drill rod (2) and the anchor drill bit (3) are removed, the steel flower tube (7) is fixed in the surrounding rock by the steel flower tube pad (15) to prevent it from slipping out of the anchor hole; Step 5: Insert the anchor rod (13) into the steel tube (7), and set an anchor rod pad (16) at one end of the anchor rod (13) close to the steel tube pad (15), and then inject grouting slurry (14) into the steel tube (7). The grouting slurry penetrates into the surrounding rock and cements the broken surrounding rock into blocks, thereby forming a high-strength pipe-anchor combined support structure, which improves the shear resistance and support strength of the anchor rod.

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