A large-diameter through-tunnel drilling step-type pneumatic drilling process

Abstract

The invention discloses a large-diameter through-tunnel drilling step-type pneumatic drilling process, which belongs to the field of through-tunnel drilling. The process comprises the following steps: one, constructing an open pipe sleeve; two, installing a working pipe sleeve; three, constructing an air down-the-hole hammer drill bit, installing the air down-the-hole hammer drill bit through the inside of the working pipe sleeve, then starting the air down-the-hole hammer drill bit to drill, and simultaneously sending high-pressure gas into the air down-the-hole hammer drill bit through an air compressor; four, inflating and pressurizing; and five, drilling and expanding the hole, shrinking the diameter of the large-diameter borehole by lowering the working pipe sleeve inside the open pipe sleeve, and then drilling by using the air down-the-hole hammer drill bit, and the wind force of the air compressor enters the air down-the-hole hammer drill bit to return rock cuttings, thereby reducing the demand for the air volume of the air compressor, reducing the safety hazards of drilling, reducing the use of the air compressor, and improving work efficiency.

Description

Technical Field

[0001] The invention relates to the technical field of tunnel drilling, and in particular to a large-diameter tunnel drilling step-type pneumatic drilling process. Background Art

[0002] The diameter of large-diameter drilling tunnels is large, the speed of rock cuttings returning is slow, the drilling process is complicated, and the mud in the borehole often exceeds 200 cubic meters. When conventional mud penetrates the tunnel, the instantaneous impact will cause destructive damage to the underground tunnels and facilities, and endanger the personal safety of underground construction workers, posing a high safety risk. At the same time, when wind drilling is used, the air volume requirement is often very high, and 5 or even more air compressors are needed to meet the requirements of rock cuttings returning construction. The cost of renting and purchasing air compressors is often higher than that of conventional drilling, which increases the cost of use. At the same time, excessive air volume will have a certain impact on underground ventilation, endangering the personal safety of underground construction workers. Summary of the Invention

[0003] In order to overcome the above-mentioned technical problems, the purpose of the present invention is to provide a large-diameter through-tunnel drilling step-type drilling wind drilling process, by lowering the working pipe sleeve inside an open pipe sleeve, the diameter of the large-diameter borehole is contracted, the area of ​​wind distribution is reduced, and the wind pressure is increased, and then drilling is carried out by using an air down-the-hole hammer drill bit. The wind force of the air compressor enters through the air down-the-hole hammer drill bit to return the rock cuttings, reducing the demand for the air volume of the air compressor, increasing the impact force on the returning rock cuttings, reducing the safety hazards of drilling, reducing the use of air compressors, and improving work efficiency.

[0004] The purpose of the present invention can be achieved through the following technical solutions:

[0005] A large-diameter through-tunnel drilling step-type pneumatic drilling process comprises the following steps:

[0006] Step 1: Open casing construction, use the drill bit mud drill on the open casing to drill a hole above the tunnel to a certain depth, then stop drilling and dilute the mud through the drill bit mud drill;

[0007] Step 2: Install the working sleeve. Remove the drill bit and mud drill. Then install the working sleeve into the open sleeve. The insertion length of the working sleeve should be less than the depth of the drill hole. Then, weld the open sleeve and the working sleeve together through a ring. At the same time, weld a vent valve on the ring.

[0008] Step 3: Air DTH Hammer Drill Bit Construction: The air DTH hammer drill bit is installed inside the working pipe sleeve through the drilling tool 4, and then the air DTH hammer drill bit is started to drill. At the same time, high-pressure gas is sent into the air DTH hammer drill bit through the air compressor, and the rock cuttings generated by drilling are discharged to the ground through the space between the working pipe sleeve and the air DTH hammer drill bit until the tunnel is completed;

[0009] Step 4: Inflation and pressurization: When the air down-the-hole hammer drill is working, the air is pumped into the space between the open pipe sleeve and the working pipe sleeve through the ventilation valve to squeeze the rock cuttings drilled by the air down-the-hole hammer drill;

[0010] Step 5: Drilling and reaming. After the tunnel is completed, replace the large-diameter reaming drill bit on the open pipe casing to complete the reaming operation.

[0011] As a further solution of the present invention: the drilling depth in step 1 is 30m from the height of the tunnel.

[0012] As a further solution of the present invention: in step 2, the working sleeve is inserted into the borehole to a depth less than 1 m.

[0013] As a further solution of the present invention: in step three, the air down-the-hole hammer drill bit penetrates into the bottom of the drill hole.

[0014] As a further solution of the present invention: the replacement of the reaming drill bit in step five is carried out in a graded manner according to the grade of the reaming drill bit.

[0015] Beneficial effects of the present invention:

[0016] In the present invention, the working sleeve is lowered inside an open sleeve to shrink the diameter of a large-diameter borehole, and then drilling is carried out using an air down-the-hole hammer drill bit. The wind from the air compressor enters through the air down-the-hole hammer drill bit to return the rock cuttings, thereby reducing the demand for the air volume of the air compressor, reducing the safety hazards of drilling, reducing the use of the air compressor, and improving work efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] The present invention will be further described below with reference to the accompanying drawings.

[0018] Figure 1 It is the process roadmap of the present invention;

[0019] Figure 2 It is a schematic diagram of tunnel drilling construction in the present invention.

[0020] In the figure: 1. Open pipe casing; 2. Working pipe casing; 3. Air down-the-hole hammer drill bit; 4. Drilling tools; 5. Tunnel. DETAILED DESCRIPTION

[0021] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making any creative efforts shall fall within the scope of protection of the present invention.

[0022] like Figure 1-Figure 2 As shown, a large-diameter through-tunnel drilling step-type pneumatic drilling process includes the following steps:

[0023] Step 1: Construction of an open casing 1, using a drill bit mud drill on the open casing 1, drilling a hole above the tunnel 5 to 30m above the tunnel 5, then stopping the drilling, and repeatedly rotating and diluting the mud through the drill bit mud drill;

[0024] Step 2: Install the working sleeve 2. Remove the drill bit and mud drill. Then install the working sleeve 2 into the open sleeve 1. The insertion length of the working sleeve 2 is less than the depth of the drill hole by 1m. Then, weld the open sleeve 1 and the working sleeve 2 together through a circular ring. At the same time, weld a vent valve on the circular ring for air intake.

[0025] Step 3: The air down-the-hole hammer drill bit 3 is installed inside the working pipe sleeve 2 through the drilling tool 4. The air down-the-hole hammer drill bit 3 penetrates into the bottom of the borehole, and then the air down-the-hole hammer drill bit 3 is started to drill. At the same time, high-pressure gas is sent to the air down-the-hole hammer drill bit 3 through the drilling tool 4 by the air compressor and ejected. The rock cuttings generated by the drilling are discharged to the ground through the space between the working pipe sleeve 2 and the air down-the-hole hammer drill bit 3 until the tunnel is completed;

[0026] Step 4: Inflation and pressurization: When the air down-the-hole hammer drill bit 3 is working, the air is pumped into the space between the open pipe sleeve 1 and the working pipe sleeve 2 through the ventilation valve to squeeze the rock cuttings drilled by the air down-the-hole hammer drill bit 3, providing further thrust for the rock cuttings to return upward, while preventing the rock cuttings from entering the space between the open pipe sleeve 1 and the working pipe sleeve 2;

[0027] Step 5: Drilling and reaming. After the tunnel is penetrated, replace the large-diameter reaming drill bit on the open pipe sleeve 1 to complete the reaming operation. When replacing the reaming drill bit, the reaming drill bit should be replaced in sequence to avoid the rock chips in the borehole from entering the tunnel 5 with the compressed gas during the reaming process, and prevent large particles of rock chips from causing blockage.

[0028] The working principle of the present invention is as follows: an open casing is lowered to 30m above the tunnel, and then a drill bit is installed to drill mud, and then the drill bit mud drill is started to repeatedly dilute the mud to complete the replacement of the mud. The working casing is lowered into an open casing 1 to less than 1m from the bottom of the borehole, and then an air down-the-hole hammer drill bit 3 is lowered into the working casing 2. The air down-the-hole hammer drill bit 3 is circulated with gas multiple times by an air compressor to completely discharge the diluted mud inside the borehole, and then the tunnel penetration operation is carried out. The rock chips generated by the air down-the-hole hammer drill bit 3 striking the rock formation during the construction process are circulated and discharged through the space between the air down-the-hole hammer drill bit 3 and the working casing. At the same time, another set of air compressors are used to vent the air between the open casing and the diameter working casing 2 through the ventilation valve on the ring. High-pressure air is introduced into the space between the open casing and the diameter working pipe sleeve 2, and the high-pressure air flows to the bottom in the space between the open casing and the diameter working pipe sleeve 2, forming two air flows with the air inside the air down-the-hole hammer drill bit 3 to squeeze the rock cuttings, which can effectively prevent the rock cutting particles from entering the space between the open casing and the diameter working pipe sleeve 2, protect the working pipe sleeve 2, and at the same time improve the efficiency of the slag return work. After the air down-the-hole hammer drill bit 3 completes the tunnel penetration operation, the diameter working casing and the air down-the-hole hammer drill bit 3 are pulled out, and the reaming drill bit is replaced to complete the subsequent construction. At the same time, when replacing the reaming drill bit, the reaming drill bit is replaced in sequence to avoid the rock cuttings in the borehole from entering the tunnel 5 with the compressed gas during the reaming process, and at the same time prevent large particles of rock cuttings from causing blockage.

[0029] For better explanation, the present invention uses an open casing of the following diameter and a working pipe sleeve 2 of the following diameter as an example for explanation. Of course, this example cannot be used to limit the scope of use of the present invention. The method of use is as follows: by lowering an open casing to, and then installing a 490 drill bit to drill mud to, and then starting the 490 drill bit mud drill to repeatedly dilute the mud to complete the replacement of the mud, the working casing is lowered into the open casing 1 to the drilling depth of 549.5 meters, and then the air down-the-hole hammer drill bit 3 is lowered into the working pipe sleeve 2, and the air down-the-hole hammer drill bit 3 is circulated with gas multiple times by the air compressor to completely discharge the diluted mud inside the borehole, and then the tunnel penetration operation is carried out. The rock chips generated by the air down-the-hole hammer drill bit 3 hitting the rock formation during the construction process are circulated and discharged through the space between the air down-the-hole hammer drill bit 3 and the working casing, and at the same time, use Another set of air compressors injects high-pressure air into the space between the open casing and the diameter working pipe sleeve 2 through the ventilation valve on the circular ring. The high-pressure air flows to the bottom in the space between the open casing and the diameter working pipe sleeve 2, and forms two air flows with the air inside the air down-the-hole hammer drill bit 3 to squeeze the rock cuttings, which can effectively prevent rock cutting particles from entering the space between the open casing and the diameter working pipe sleeve 2, protect the working pipe sleeve 2, and at the same time improve the efficiency of the slag return work. After the air down-the-hole hammer drill bit 3 completes the tunnel penetration operation, the diameter working casing and the air down-the-hole hammer drill bit 3 are pulled out, and the reaming drill bit is replaced to complete the subsequent construction. At the same time, when replacing the reaming drill bit, the reaming drill bit is replaced in sequence to avoid the rock cuttings in the borehole from entering the tunnel 5 with the compressed gas during the reaming process, and to prevent large particles of rock cuttings from causing blockage.

[0030] The above is a detailed description of an embodiment of the present invention. However, the content described is only a preferred embodiment of the present invention and should not be considered to limit the scope of the present invention. All equivalent changes and improvements made within the scope of the present invention should still fall within the scope of the patent coverage of the present invention.

Claims

1. A large-diameter through-tunnel drilling step-type pneumatic drilling process, characterized in that: The following steps are involved: Step 1: Construction of an open casing (1), drilling a hole to a certain depth above the tunnel (5) through a drill bit mud drill on the open casing (1), then stopping the drilling, and diluting the mud through the drill bit mud drill; Step 2: Install the working sleeve (2). Disassemble the drill bit mud drill, and then install the working sleeve (2) into the inside of the open sleeve (1). The insertion length of the working sleeve (2) is less than the depth of the drill hole. Then, the open sleeve (1) and the working sleeve (2) are welded together through a circular ring, and a vent valve is welded on the circular ring. Step 3: Construction of the air down-the-hole hammer drill bit (3). The air down-the-hole hammer drill bit (3) is installed inside the working pipe sleeve (2) through the drilling tool (4). Then, the air down-the-hole hammer drill bit (3) is started to drill. At the same time, high-pressure gas is sent into the air down-the-hole hammer drill bit (3) through the air compressor, and the rock cuttings generated by the drilling are discharged to the ground through the space between the working pipe sleeve (2) and the air down-the-hole hammer drill bit (3) until the tunnel is completed. Step 4: Inflate and pressurize. When the air down-the-hole hammer drill bit (3) is working, the air is pumped into the space between the open pipe sleeve (1) and the working pipe sleeve (2) through the ventilation valve and an external air compressor is used to squeeze the rock cuttings drilled by the air down-the-hole hammer drill bit (3); Step 5: Drilling and reaming. After the tunnel is drilled through, a large-diameter reaming drill bit is replaced on the open casing (1) to complete the reaming operation.

2. A large-diameter through-tunnel drilling step-type pneumatic drilling process according to claim 1, characterized in that: The drilling depth in step 1 is 30m from the height of the tunnel (5).

3. The large-diameter through-tunnel drilling step-type pneumatic drilling process according to claim 1 is characterized in that: In step 2, the working sleeve (2) is inserted into the borehole to a depth less than 1 m.

4. A large-diameter through-tunnel drilling step-type pneumatic drilling process according to claim 1, characterized in that: In step 3, the air down-the-hole hammer drill bit (3) penetrates into the bottom of the drill hole.

5. The large-diameter through-tunnel drilling step-type pneumatic drilling process according to claim 1 is characterized in that: In step five, the reaming drill bits are replaced in order according to their grade.

Images