Drill bit guiding system for new and old subway tunnels and super-long pipe shed construction method

Abstract

The invention relates to a drill bit guiding system for new and old subway tunnels and an ultra-long pipe shed construction method.The drill bit guiding system for the new and old subway tunnels comprises a drill bit, a drill rod and a monitoring platform and further comprises a connecting steel pipe arranged between the drill bit and the drill rod, and a cavity is formed in the connecting steel pipe; a cylindrical mounting box is fixedly arranged in a cavity of the connecting steel pipe, the surface of the mounting box is attached to the inner wall of the connecting steel pipe in a sealed mode, a spiral flow channel surrounding the mounting box is formed in the inner wall of the connecting steel pipe in the axial direction of the mounting box, one end of the spiral flow channel communicates with the interior of the drill rod, and the other end of the spiral flow channel extends to the front end of the drill bit. One end, close to the drill rod, of the sensor is connected with a signal wire penetrating through the mounting box and the connecting steel pipe, the other end of the signal wire is electrically connected with the monitoring platform, and a gap between the sensor and the mounting box is filled with filler; the problem that in the prior art, high temperature is generated during drilling of a drill bit, normal work of a sensor is affected, and long-distance pipe shed construction cannot be conducted is solved.

Description

Technical Field

[0001] The present invention relates to the technical field of underground construction engineering, and particularly relates to a drill bit guiding system for new and old subway tunnels and a construction method for extra-long pipe roofs. Background Art

[0002] The pipe roof advanced pre-support technology, as an auxiliary construction technology for strengthening the stratum, stabilizing the vault and the heading face, and reducing the ground settlement, has been widely applied in tunnel construction. The traditional construction process for extra-long pipe roofs generally adopts the process of drilling first and then jacking the pipe. During the drilling process, due to the influence of the self-weight of the drill pipe of the pipe roof, the drill bit is prone to sag, resulting in difficulties in jacking the pipe and reducing the construction quality of the pipe roof. For driving extra-long pipe roofs, the conventional construction process cannot guarantee effective hole formation and driving accuracy. And simply following the pipe during drilling cannot control the direction, and it is very difficult to ensure the driving accuracy of the extra-long large-diameter pipe roof. Simply guiding drilling will encounter many adverse factors such as site restrictions in the construction of long pipe roofs in urban subways. In a wireless underground positioning system, since the receiver needs to be located on the road surface directly above the drilling trajectory for tracking and monitoring, it is often very difficult to receive correctly due to the influence of above-ground and underground buildings, ground traffic, and underground pipelines. At present, most of the drilling of extra-long pipe roofs is achieved by installing monitoring devices inside the drill bit for the drilling construction of extra-long pipe roofs.

[0003] For example, in the Chinese utility model patent with the existing patent application number 201320404166.0, it discloses a device for improving the construction accuracy of long pipe roofs. The technical key point is the monitoring equipment installed inside the drill bit, which can monitor the angle of the drill bit deviating from the designed position. However, this patent lacks protection for the sensor, and the monitoring equipment is extremely easy to be damaged during actual construction, resulting in construction delays.

[0004] The existing Chinese invention patent with the patent application number 201810841592.8 discloses a drill bit guiding system for new and old subway tunnels and a construction method for arc-shaped extra-long pipe roofs. The technical key point is fixedly installed inside the drill bit. A guiding sensor is arranged inside the installation box, and asbestos is filled in the gap between the guiding sensor and the installation box. The guiding sensor can accurately control the drilling angle and directly use the steel pipe of the pipe roof as the drill pipe, realizing the synchronous progress of drilling and pipe laying work, simplifying the construction steps. The asbestos can reduce the influence of the heat and vibration generated during the drilling process of the steel pipe on the guiding sensor. However, during the continuous high temperature generated when the drill bit drills, the heat conduction performance of asbestos is relatively low, which may cause heat to accumulate inside the installation box instead of being quickly dissipated. After long-term use, the temperature around the guiding sensor may gradually increase, affecting the accuracy of the sensor and resulting in deviations during drilling, making it impossible to carry out long-distance pipe roof construction. Summary of the Invention

[0005] One of the objectives of the present invention is to provide a drill bit guiding system for new and old subway tunnels, which is used to solve the problem in the prior art that high temperature is generated during the drilling of the drill bit, affecting the normal operation of the sensor and resulting in the inability to carry out long-distance pipe shed construction; the second objective is to propose a construction method for ultra-long pipe sheds.

[0006] To achieve the above objectives, on the one hand, the technical solution adopted by the present invention is as follows: A drill bit guiding system for new and old subway tunnels, comprising a drill bit, a drill pipe and a monitoring platform, further comprising a connecting steel pipe arranged between the drill bit and the drill pipe. The connecting steel pipe is internally provided with a cavity. A cylindrical installation box coaxial with the connecting steel pipe is fixedly arranged in the cavity of the connecting steel pipe. The surface of the installation box is hermetically fitted with the inner wall of the connecting steel pipe. A spiral flow channel surrounding the installation box is axially formed on the inner wall of the connecting steel pipe. One end of the spiral flow channel is communicated with the inside of the drill pipe, and the other end extends to the front end of the drill bit. A sensor is coaxially and fixedly arranged in the installation box. One end of the sensor close to the drill pipe is connected with a signal line passing through the installation box and the connecting steel pipe. The other end of the signal line is electrically connected with the monitoring platform. The gap between the sensor and the installation box is filled with a filler.

[0007] According to the above technical solution, the sensor fixed in the installation box can real-time monitor the position and attitude of the drill bit, providing accurate guiding information for the operator, ensuring that the tunnel excavation is carried out according to the predetermined trajectory, and improving the construction accuracy and efficiency; the sensor is coaxially installed with the drill bit, ensuring the accuracy of the measurement; the spiral flow channel in the connecting steel pipe is arranged outside the installation box and forms a wrapping state for the installation box, so that when the circulating mud flows through the spiral flow channel, a water cooling system is formed for the installation box and the sensor inside it, isolating the influence of the high temperature generated by the friction between the drill bit and the rock or soil on the sensor, protecting the performance of the sensor and prolonging its service life. By setting the filler, not only a good heat insulation effect is provided, but also a vibration isolation function is achieved, reducing the influence of the vibration during the operation of the drill bit on the sensor and improving the stability and reliability of the system.

[0008] Furthermore, a micro cooling mechanism is arranged at the position of the spiral flow channel close to the drill bit end. The micro cooling mechanism comprises a spring and a tapered block located in the spiral flow channel. The diameter of the tapered block gradually increases along the flowing direction of the fluid in the spiral flow channel. The side wall of the tapered block is fitted with the side wall of the spiral flow channel. One end of the spring is fixedly connected with the large diameter end of the tapered block, and the other end is fixedly connected with the inner wall of the spiral flow channel. The spring makes the tapered block have a tendency to seal the spiral flow channel.

[0009] According to the above technical solution, under normal circumstances, the elastic force of the spring causes the conical block to have a tendency to seal the spiral flow channel, thereby preventing the backflow of mud in the non-working state. However, when the mud flows through the spiral flow channel under high pressure, its pressure will overcome the elastic force of the spring and push the conical block towards the center of the flow channel, thus opening a channel for the mud to pass through. When the mud flows through the gap between the conical block and the spiral flow channel, due to the increase in flow velocity and the decrease in cross-sectional area, a low-pressure area (Venturi effect) will be generated. At the same time, according to Bernoulli's law, the increase in flow velocity will cause the pressure to decrease, and the air inside the installation box will be adsorbed through the first air duct and the second air duct, that is, the heat around the sensor will be taken away, so that the heat will not accumulate inside the installation box but will be quickly dissipated. This can not only effectively reduce the working temperature of the sensor but also prevent performance degradation or damage caused by high temperature. By reducing the influence of high temperature on the sensor, the micro-cooling mechanism helps to maintain the stability and reliability of the system, which is crucial for ensuring the precise guidance and monitoring of tunnel boring.

[0010] Furthermore, a one-way valve is provided in the first air duct.

[0011] According to the above technical solution, the main function of the one-way valve is to allow fluid to flow in one direction while preventing it from flowing in the opposite direction. Installing a one-way valve in the first air duct of the drill bit guidance system can effectively prevent the backflow of mud during the flow process, ensure the smooth flow of mud in the predetermined direction, and avoid unnecessary interference or damage to the system. In the mud circulation system, due to various pressure and temperature changes, as well as possible impurities and particulate matters, these factors may damage the system components. The presence of the one-way valve can, to a certain extent, reduce the influence of these adverse factors on the system components and play a protective role for the sensor.

[0012] Furthermore, a third air duct is provided on the side wall of the installation box near the drill pipe end, and a fourth air duct is provided on the surface of the connecting steel pipe near the drill pipe end. The third air duct is used to connect the inside of the installation box with the fourth air duct.

[0013] According to the above technical solution, the settings of the third air duct and the fourth air duct provide an additional ventilation path for the inside of the installation box. During the operation of the drill bit, the sensor inside the installation box will generate a certain amount of heat. Through these two air ducts, the external cold air can flow into the installation box and exchange heat with the internal hot air, thereby reducing the temperature inside the installation box and improving the heat dissipation efficiency. At the same time, during the tunneling process, the inside of the drill pipe and the connecting steel pipe may be subject to pressure fluctuations from the mud circulation system. The presence of the third air duct and the fourth air duct helps to balance the pressure difference between the inside of the installation box and the external environment and reduce the risk of seal failure or sensor component damage caused by pressure imbalance.

[0014] Further, a first air passage is formed between the side wall of the spiral flow passage where it fits with the conical block and one end of the mounting box close to the drill bit. A second air passage is formed in the side wall of the mounting box, and the second air passage communicates the interior of the mounting box with the first air passage.

[0015] According to the above technical solution, when flowing through the spiral flow passage under high pressure, the design of the conical block causes the flow rate of the liquid to increase when flowing through the joint of the conical block and the spiral flow passage, forming a Venturi effect, resulting in a pressure drop in this area. At this time, the hot air in the mounting box can enter the first air passage through the second air passage and exchange heat with the low-temperature mud. Subsequently, the mud mixed with cold air or low-temperature fluid continues to flow along the spiral flow passage to the front end of the drill bit, providing further cooling for components such as the drill bit and the sensors in the mounting box, which helps to reduce the working temperature of components such as sensors and improve their stability and reliability.

[0016] The settings of the first air passage and the second air passage increase the heat exchange area between the interior of the mounting box and the external environment, enabling the heat in the mounting box to be dissipated to the external environment more quickly. This helps to prevent component overheating caused by heat accumulation, thereby extending the service life of the components.

[0017] Further, the filler is made of a breathable material.

[0018] According to the above technical solution, the breathable material allows air to circulate freely, reducing air resistance, enabling the air inside to circulate better, and accelerating heat dissipation.

[0019] Further, heat dissipation fins are provided on the sensor, and the number of the heat dissipation fins is multiple. Each of the heat dissipation fins is evenly arranged on the outer surface of the sensor.

[0020] Further, the drill bit includes a drill bit body and a plurality of crushing racks. Each of the crushing racks is fixed on the top of the drill bit body, and each of the crushing racks is twisted in a clockwise or counterclockwise direction; A first chamber and a second chamber that communicate with each other are provided in the drill bit body. A plurality of spraying holes that communicate with the second chamber are provided at the top of the drill bit body; A fifth air passage is provided in the connecting steel pipe, and the fifth air passage is communicated with the first chamber; the first chamber has a conical structure.

[0021] According to the above technical solution, each of the crushing racks is twisted in a clockwise or counterclockwise direction. This design enables the drill bit to generate more complex crushing actions during rotation. The crushing racks not only perform conventional rotational crushing but also produce additional shearing and squeezing effects through twisting, which helps to more effectively crush rocks or other materials. This dynamic crushing method can better adapt to rocks with different hardnesses and structures than single rotational crushing, improving the crushing efficiency and effect.

[0022] The first chamber and the second chamber which are arranged in the drill bit body and communicate with each other, and the fifth air duct in the connecting steel pipe together constitute an efficient cooling and lubrication system. When the coolant enters the first chamber through the fifth air duct, due to the conical structure of the first chamber, it plays a certain pressurizing role. Subsequently, these coolants can be ejected through the second chamber and the splash holes, directly acting on the crushing rack and the drill bit body to achieve effective cooling and lubrication, which helps to reduce the temperature of the drill bit during operation, reduce wear, and extend the service life of the drill bit.

[0023] Furthermore, the part of the first air duct close to the spiral flow channel is the air duct part, and the air duct part is distributed at an acute angle to the radial direction of the spiral flow channel.

[0024] According to the above technical solution, since the air duct part is distributed at an acute angle to the radial direction of the spiral flow channel, the air flow will be subjected to a certain guiding effect before entering the spiral flow channel, making it easier for the air flow to rotate along the direction of the spiral flow channel, enabling the air flow to enter the spiral flow channel more smoothly, which helps to enhance the eddy current effect, improve the rotation intensity and stability of the air flow, and thus improve the cooling effect.

[0025] On the other hand, the present invention also proposes a construction method for an extra-long pipe shed, which is implemented by using the drill bit guiding system for new and old subway tunnels as described above. The construction method includes the following steps: Erect a pipe shed steel arch, and set a guiding pipe on the steel arch; b. Move the drilling rig to the tunnel entrance, fix and position it; c. Design the drilling trajectory and construct the borehole by using the pipe-following drilling method; d. Use the drill bit guiding system for new and old subway tunnels to strictly control the angle of the borehole, and timely correct the deviation of the pipe shed steel pipe whose drilling angle exceeds the allowable deviation, so that the pipe shed steel pipe is driven according to the pre-designed path; e. After each pipe shed is driven, withdraw the drill pipe and drill bit of the drilling equipment; f. Conduct high-pressure air hole cleaning on the pipe shed steel pipe, and grout after passing the acceptance.

[0026] The beneficial effects of the present invention: By setting a wire sensor, the present invention can control the drilling direction, the pipe shed steel pipe drills according to the preset trajectory, and can real-time feedback the drilling parameters, which is beneficial to the control of the drilling direction, the pipe shed driving accuracy is very high, and it can be applied to urban subway construction.

[0027] By setting a spiral flow channel, the present invention uses the mud to form water-cooled cooling for the sensor working environment, and forms good protection for the sensor.

[0028] Through the micro cooling mechanism, the present invention continuously extracts the hot air inside the installation box, inhales fresh cold air, further reduces the impact of high temperature on the sensor, ensures the accuracy of the sensor, enables the drill bit guiding system to drill in the long-distance pipe shed, and ensures the orderly progress of the pipe shed construction.

[0029] In the present invention, the side wall of the part of the spiral flow channel close to the front end of the installation box is recessed inward to form an installation chamber for installing a spring and a conical block. The spring and the conical block form a check valve in the installation chamber, so that the high-pressure mud / coolant can only pass unidirectionally. When the mud reaches the installation chamber, the check valve opens at this time, and the mud will also enter the subsequent flow channel through the narrow gaps on both sides of the conical block. According to the Venturi effect and Bernoulli's law, as the heat in the installation box increases, the internal pressure will gradually increase, while the installation chamber is a low-pressure chamber at this time. Then the installation chamber will inhale the air in the first air passage through the first air passage, mix it with the mud and continue to flow. The first air passage is connected to the second air passage after continuous bending. When the mud flows through the installation chamber, it will adsorb the air inside the installation box through the first air passage and the second air passage, that is, take away the heat around the sensor, form a micro cooling system for the sensor, so that the heat will not accumulate inside the installation box, but will be quickly dissipated, reducing the internal temperature.

[0030] Other advantages, objectives and features of the present application will be described to some extent in the subsequent specification, and to some extent, will be obvious to those skilled in the art based on the study of the following text, or can be taught from the practice of the present application. The objectives and other advantages of the present application can be achieved and obtained through the following specific embodiments. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] Figure 1 It is a schematic structural diagram of a drill bit guiding system for new and old subway tunnels of the present invention; Figure 2 It is Figure 1 An enlarged structural diagram of part A; Figure 3 It is Figure 2 An enlarged structural diagram of part B; Figure 4 It is a schematic overall structure diagram of the drill bit of a drill bit guiding system for new and old subway tunnels of the present invention; Figure 5 It is a schematic plan structure diagram of the drill bit of a drill bit guiding system for new and old subway tunnels of the present invention; Figure 6 It is in a drill bit guiding system for new and old subway tunnels of the present invention Figure 5 A-A sectional view schematic diagram; Figure 7 It is a schematic construction diagram of new and old subway tunnels of the present invention.

[0032] Among them, there are drill bit 1, drill bit body 101, crushing rack 102, first chamber 103, second chamber 104, splash holes 105, connecting steel pipe 2, drill pipe 3, spiral flow channel 4, installation box 5, sensor 6, filler 7, heat dissipation fins 8, installation chamber 9, conical block 10, spring 11, first air duct 12, one-way valve 13, second air duct 14, third air duct 15, fourth air duct 16, and fifth air duct 17. Specific implementation manners

[0033] The following will describe the implementation manners of the present invention with reference to the accompanying drawings and preferred embodiments. Those skilled in the art can easily understand other advantages and effects of the present invention from the content disclosed in this specification. The present invention can also be implemented or applied through other different specific implementation manners. Various details in this specification can also be modified or changed based on different viewpoints and applications without departing from the spirit of the present invention. It should be understood that the preferred embodiments are only for explaining the present invention, rather than for limiting the protection scope of the present invention.

[0034] It should be noted that the drawings provided in the following embodiments only illustrate the basic concept of the present invention in a schematic manner. Therefore, only the components related to the present invention are shown in the drawings, rather than being drawn according to the number, shape, and size of the components in actual implementation. The types, quantities, and ratios of the components in actual implementation can be arbitrarily changed, and the component layout type may also be more complex.

[0035] A drill bit guiding system for new and old subway tunnels, as Figures 1 to 7 shown, includes drill bit 1, drill pipe 3, and a monitoring platform. It also includes a connecting steel pipe 2 coaxially and fixedly arranged on the drill bit 1. It should be understood that the connecting steel pipe 2 can be a part of the drill bit 1. The connecting steel pipe 2 is located between the drill bit 1 and the drill pipe 3. There is a cavity inside the connecting steel pipe 2. A cylindrical installation box 5 coaxial with the connecting steel pipe 2 is fixedly arranged inside the cavity of the connecting steel pipe 2. The surface of the installation box 5 is hermetically attached to the inner wall of the connecting steel pipe 2. A spiral flow channel 4 surrounding the installation box 5 is axially opened on the inner wall of the connecting steel pipe 2 along the installation box 5. One end of the spiral flow channel 4 is communicated with the inside of the drill pipe 3, and the other end extends to the front end of the drill bit 1. A sensor 6 is coaxially and fixedly arranged inside the installation box 5. One end of the sensor 6 close to the drill pipe 3 is connected with a signal line (not shown in the figure) passing through the installation box 5 and the connecting steel pipe 2. The other end of the signal line is electrically connected to the monitoring platform. The gap between the sensor 6 and the installation box 5 is filled with a filler 7.

[0036] During the pipe-roof construction, a large amount of heat is generated by the friction between the drill bit 1 and the rock or soil during drilling, resulting in an increase in the temperature of the drill bit 1. Excessive temperature may cause the performance degradation or damage of the sensor 6. The installation and protection of the sensor 6 are key links to ensure the accurate monitoring of the drilling orientation of the drill bit 1. In this embodiment, in order to achieve the best measurement effect, the sensor 6 is coaxially installed with the drill bit 1, and various measures are taken to protect the sensor 6 from high temperature and vibration. The drill rig has two input pipelines, one connected to the high-pressure oil pump to provide the feeding power, and the other connected to the mud pump to provide the drilling circulating mud. During drilling, the high-pressure liquid is ejected from the front end of the drill bit 1 through the drill pipe 3 and the connecting steel pipe 2 to scour the front soil mass, and at the same time, the drill pipe 3 rotates and advances forward. The functions of the circulating mud are as follows: on the one hand, it scours and softens the front soil mass, and on the other hand, it plays a role in protecting the wall and reducing the temperature of the drill bit 1 to protect the internal sensor 6. By arranging a spiral flow channel 4 around the installation box 5 in the connecting steel pipe 2, when the mud flows through the spiral flow channel 4, a water-cooling system is formed for the installation box 5 to reduce the temperature of the installation box 5 and further protect the sensor 6. Such a structural design is simple, does not affect the strength of the drill bit 1, and uses the mud to form a double cooling for the working environment of the sensor 6, which is compact and efficient.

[0037] Furthermore, as Figure 4 , Figure 5 and Figure 6As shown, the drill bit 1 includes a drill bit body 101 and a plurality of crushing racks 102. Each crushing rack 102 is fixed to the top of the drill bit body 101, and each crushing rack 102 is twisted in a clockwise or counterclockwise direction; a first chamber 103 and a second chamber 104 that communicate with each other are provided inside the drill bit body 101, and a plurality of splash holes 105 that communicate with the second chamber 104 are provided at the top of the drill bit body 101; a fifth air passage 17 is provided inside the connecting steel pipe 2, and the fifth air passage 17 communicates with the first chamber 103; the first chamber 103 has a conical structure. According to the above technical solution, each crushing rack 102 is twisted in a clockwise or counterclockwise direction. This design enables the drill bit 1 to generate more complex crushing actions during rotation. The crushing rack 102 not only performs conventional rotational crushing, but also can generate additional shearing and extrusion effects through the twisting design, which helps to more effectively crush rocks or other materials. This crushing method is more adaptable to rocks of different hardnesses and structures, improving the crushing efficiency and effect. The mutually communicating first chamber 103 and second chamber 104 provided inside the drill bit body 101, and the fifth air passage 17 inside the connecting steel pipe 2 together constitute an efficient cooling system. When high-pressure mud / coolant enters the first chamber 103 through the fifth air passage 17, due to the conical structure of the first chamber 103, it can play a certain pressurizing role. Subsequently, these coolants can be ejected from the splash holes 105 through the second chamber 104 and directly act on the crushing rack 102 and the drill bit body 101 to achieve effective cooling and lubrication, which helps to reduce the temperature of the drill bit 1 during operation, reduce wear, and extend the service life of the drill bit 1.

[0038] A micro cooling mechanism is provided at a position of the spiral flow channel 4 close to one end of the drill bit 1. The micro cooling mechanism includes a spring 11 and a tapered block 10 located in the spiral flow channel 4. The diameter of the tapered block 10 gradually increases along the fluid flow direction of the spiral flow channel 4. The side wall of the tapered block 10 is attached to the side wall of the spiral flow channel 4. One end of the spring 11 is fixedly connected to the large-diameter end of the tapered block 10, and the other end is fixedly connected to the inner wall of the spiral flow channel 4. The spring 11 makes the tapered block 10 tend to seal the spiral flow channel 4. A first air passage 12 is provided between the side wall of the spiral flow channel 4 where it is attached to the tapered block 10 and one end of the mounting box 5 close to the drill bit 1. A second air passage 14 is provided on the side wall of the mounting box 5. The second air passage 14 communicates the inside of the mounting box 5 with the first air passage 12. In this embodiment, the side wall of the part of the spiral flow channel 4 close to the front end of the mounting box 5 is recessed inward to form a mounting chamber 9 for mounting the spring 11 and the tapered block 10. The spring 11 and the tapered block 10 form a check valve in the mounting chamber 9, enabling high-pressure mud to pass only unidirectionally. When the mud reaches the mounting chamber 9, the check valve opens at this time, and the mud will also enter the subsequent flow channel through the narrow gaps on both sides of the tapered block 10. According to the Venturi effect and Bernoulli's law, as the heat in the mounting box 5 increases, the internal pressure will gradually increase. At this time, the mounting chamber 9 is a low-pressure chamber, so the mounting chamber 9 will inhale the air in the first air passage 12 through the first air passage 12, mix it with the mud, and then continue to flow. After the first air passage 12 is continuously bent, it is aligned and communicated with the second air passage 14. When the mud flows through the mounting chamber 9, it will adsorb the air inside the mounting box 5 through the first air passage 12 and the second air passage 14, that is, take away the heat around the sensor 6, forming a micro cooling system for the sensor 6, so that the heat will not accumulate inside the mounting box 5 but will be quickly dissipated.

[0039] A check valve 13 is provided in the first air passage 12 to prevent the mud from flowing into the mounting box 5 through the first air passage 12 when the drill bit 1 stops rotating. In this embodiment, the check valve 13 includes a rubber sheet and a cross. The rubber sheet is disk-shaped. The cross is fixed on the inner wall of the first air passage 12. The rubber sheet is mounted on the cross. The cross is located on the side of the rubber sheet close to the second air passage 14. When the mud flows through the mounting chamber 9, an adsorption force is generated in the first air passage 12. The air inside the mounting box 5 comes to the first air passage 12 through the second air passage 14. The pressure of the air will cause the edge of the disk-shaped rubber sheet to bend towards the flow channel side. The air passes through the check valve 13 and enters the flow channel to mix with the mud and flow away. When the drilling is completed and the mud stops flowing, the check valve 13 can prevent the remaining mud staying in the spiral flow channel 4 from flowing into the mounting box 5 and affecting the sensor 6. According to the actual situation, the aperture of the first air passage 12 can be appropriately increased to facilitate the installation of the check valve 13.

[0040] In the above embodiment, such as Figure 3As shown in the figure, the part of the first air passage 12 close to the spiral flow passage 4 is the air passage part. The air passage part is distributed at an acute angle to the radial direction of the spiral flow passage 4. When the drill bit 1 rotates and drills, the mud in the connecting steel pipe 2 will experience centrifugal force. This centrifugal force will cause the mud to move towards the outside of the connecting steel pipe 2, resulting in changes in the fluid velocity and pressure distribution in the inner part of the spiral flow passage 4, thereby affecting the adsorption force generated by the Venturi effect. In order to ensure the effective generation of the adsorption force, in the present invention, the air passage part of the first air passage 12 is arranged at an acute angle to the radial direction of the spiral flow passage 4. At the same time, the distance between the air passage part and the spiral flow passage 4 becomes smaller along the direction of the mud flow. The air flow will be subjected to a certain guiding effect before entering the spiral flow passage 4, making it easier for the air flow to rotate along the direction of the spiral flow passage 4, enabling the air flow to enter the spiral flow passage 4 more smoothly, helping to enhance the eddy current effect, improving the rotation intensity and stability of the air flow, and thus improving the cooling effect. Such a structural design is simple, reasonable and ingenious, minimizing the influence of centrifugal force on the mud flow, being able to maximize the role of the first air passage 12, and still being able to utilize the Venturi effect and Bernoulli's law to achieve an effective adsorption effect.

[0041] A number of heat dissipation fins 8 are fixedly arranged on the surface of the sensor 6 to increase the heat dissipation effect of the sensor 6 itself. In this embodiment, the heat dissipation fins 8 do not contact the inner wall of the installation box 5. On the one hand, it reduces the transmission of vibration, preventing the vibration of the drill bit 1 from being directly transmitted to the sensor 6 through the connecting steel pipe 2, the installation box 5, and the heat dissipation fins 8. On the other hand, the heat dissipation fins 8 do not seal the gap between the installation box 5 and the sensor 6, facilitating air flow.

[0042] A third air passage 15 is opened on the side wall of the installation box 5 close to one end of the drill pipe 3, and a fourth air passage 16 is opened on the surface of the connecting steel pipe 2 close to one end of the drill pipe 3. The third air passage 15 is used to connect the inside of the installation box 5 with the fourth air passage 16. The filler 7 is made of a breathable material. In this embodiment, the filler 7 can be selected from open-cell polyurethane foam, open-cell silicone foam, glass fiber cotton, ceramic fiber cotton, etc. These materials have good air permeability while having heat insulation properties, and can effectively reduce the influence of vibration on the sensor 6. Utilizing the air permeability of the filler 7, it can be used in cooperation with the micro cooling mechanism to continuously transport the air behind the connecting steel pipe 2 through the fourth air passage 16 and the third air passage 15 to the inside of the installation box 5, and then through the second air passage 14 and the first air passage 12 to the mud, and the air is mixed with the mud and ejected from the front end of the drill bit 1, achieving the effect of continuously replacing the air in the working environment of the sensor 6.

[0043] On the other hand, this embodiment also proposes an ultra-long pipe shed construction method; a. Set up the pipe shed steel arch and install guide pipes on the steel arch. Use a theodolite to measure and lay out the position of the guide wall pipe shed steel arch, and install the pipe shed steel arch. Weld the guide pipes firmly to the outer edge of the pipe shed steel arch. The guide pipes are made of φ128*5mm hot-rolled seamless steel pipes with a length of 1 meter.

[0044] b. Move the drill rig to the position between the new subway tunnel entrance and the old subway tunnel entrance, fix and position it. First, use a down-the-hole drill to drill to the designed depth, and then use a drill bit guidance system to drill holes. As shown in Figure 7 , the position D between the new subway tunnel entrance C and the old subway tunnel entrance E is the position where the pipe shed needs to be installed. Horizontal drilling is carried out at this position D for pipe shed construction. During the preliminary preparation process and the pipe shed construction process, the drill rig position needs to be frequently moved and the height of the drill rig needs to be adjusted. Therefore, a stable working platform should be set up. After the working platform is set up, use a 10t manual hoist to lift the drill rig onto the working platform and move it along the working platform guide rail to the operating position. During construction, determine the position and height of the drill rig for the hole position according to factors such as the position of the pipe shed, the length of the drill tool, and the height of the drill rig. The drill pipe 3 is required to be parallel to the direction of the pre-set hole pipe, and the position of the drill rig must be accurately verified. After the drill rig is accurately positioned and the direction and angle meet the requirements, when the pipe shed position is located in the plain pile, directly use a down-the-hole drill to drill to the designed depth. When starting the hole, it should be at low speed and low pressure. After the hole is formed for 1.0m, normal pressure can be used for drilling. After drilling a certain depth, connect the drill pipe, follow up the casing, and continue drilling. The drilling operation should ensure accurate angle, straight hole body, sufficient depth, and clean rock powder. During the drilling process, always pay attention to the change of the drill pipe angle and ensure that the drill rig does not shift. Use an instrument to check whether the angle of the drill pipe is correct and whether the drill rig has shifted every 3m of drilling to ensure the drilling direction. When the drilling deviation is too large, use special drill bits and other methods to correct the deviation for adjustment.

[0045] c. Design the drilling trajectory and use the pipe-following drilling method for drilling construction. The design of the drilling trajectory should comprehensively consider factors such as formation conditions and pipe shed length. Test holes should be made before the formal drilling to verify the formation and correct the designed trajectory. For example, when building a new tunnel under an existing tunnel, in the case of a relatively low vertical clear distance between the new and old tunnels (that is Figure 7When the height between the outer wall of the new subway tunnel opening C and the outer wall of the old subway tunnel opening E is less than 3m, the drilling trajectory should be kept straight without bending. If the borehole deflects, it may touch the existing tunnel above (the old subway tunnel opening E), or create an obstacle for the shield tunnel below (the new subway tunnel opening C). In this embodiment, the pipe-jacking drilling method is a drilling method, that is, while drilling, the casing is pressed in, or the casing is pressed in advance, and then the drill tool follows to drill. After the drill rig is accurately positioned and the direction and angle meet the requirements, the pipe-roof steel pipe is located at the plain pile, and the down-the-hole drill is directly used to drill to the designed depth. When starting the hole, it should be at low speed and low pressure. After the hole is formed for 1.0m, the normal pressure can be used for drilling. After drilling to a certain depth, the drill pipe 3 is connected, the casing is advanced, and the drilling continues. The drilling operation should be accurate in angle, straight in hole body, sufficient in depth, and the rock powder should be cleaned up; during the drilling process, the change of the angle of the drill pipe 3 should be always noted, and the drill rig should not be displaced. Every 3m of drilling, the instrument is used to check whether the angle of the drill pipe 3 is correct and whether the drill rig is displaced to ensure the drilling direction. This is the conventional technical means of the pipe-jacking drilling module in the prior art, and will not be elaborated here.

[0046] d. Use the bit 1 guiding system of the new and old subway tunnels to strictly control the drilling angle, and correct the deviation of the pipe-roof steel pipe whose drilling angle exceeds the allowable deviation in time, so that the pipe-roof steel pipe is driven according to the pre-designed path; in this embodiment, the monitoring platform includes a power supply and a remote display, and a wired guiding mechanism is composed of a sensor 6 (probe), a signal line, a remote display and a power supply. Its working principle is that the sensor 6 located in the bit 1 transmits the signal directly to the remote display through the signal line in the drill pipe 3, and monitors the drilling azimuth of the bit 1 at all times. If the borehole deflects too much, correction is required.

[0047] e. After each pipe-roof is driven, withdraw the drill pipe 3 and the bit 1 of the drilling equipment, and maintain and test the sensor 6; install the pipe-roof in a timely and rapid manner to ensure that the pipe-roof steel pipe is stably sent to the bottom of the hole. The pipe-roof steel pipe adopts φ108*6mm hot-rolled seamless steel pipe. In the early stage, manual pipe feeding can be used. When the depth increases and the resistance increases and manual feeding is impossible, the drill rig is used to jack in. After the pipe feeding is completed, the casing is withdrawn with the help of the drill rig.

[0048] f. Conduct high-pressure air hole cleaning on the pipe-roof steel pipe, and start grouting after passing the acceptance; after the pipe-roof steel pipe is jacked in, the pipe-roof steel pipe is hole-cleaned to ensure that the grouting pipeline is smooth and unblocked, and the grouting pipeline is inspected. After passing the inspection, start preparing for grouting. The grout adopts M30 cement slurry, and the diffusion radius is 0.5m. Tests should be done before grouting, and the grouting pressure and grouting volume should be controlled to avoid adverse effects on the line and ensure the reinforcement effect.

[0049] The present invention uses a wired sensor 6 for guidance, which can monitor the drilling direction in real time, enabling the pipe-roof steel pipe to drill according to a preset trajectory and providing real-time feedback of drilling parameters, facilitating the control of the drilling direction and achieving a very high precision in pipe-roof installation. In the present invention, the sensor 6 located inside the drill bit 1 transmits signals directly to a remote display through the signal line inside the drill pipe 3, monitoring the drilling azimuth of the drill bit 1 in real time. During the drilling process, the drill rig operator controls the inclination angle of the drill bit 1 based on the inclination value on the remote display. The deviation of the inclination angle of the drill bit 1 is controlled within ±0.3%. When a deviation is detected, the inclination angle of the drill bit 1 is adjusted according to the clock face value of the drill bit 1 on the remote display. Generally, the test frequency is once per meter or per section of the drill pipe 3. According to the installed length, the drilling trajectory of the designed line is determined, and the drilling is carried out under the monitoring of the guidance system, overcoming the problems of signal tracking affected and restricted by ground traffic and above-ground and underground buildings (structures) in the construction of urban subways by the wireless guidance system. At the same time, it can effectively control ground settlement, protect underground pipelines, existing tunnels, etc., and the ground road traffic is not affected. During drilling, high-pressure liquid (i.e., mud) is ejected from the front end of the drill bit 1 through the drill pipe 3 and the connecting steel pipe 2 to scour the soil in front. At the same time, the drill pipe 3 rotates and advances forward. When the mud flows through the connecting steel pipe 2, it forms multiple cooling effects on the sensor 6 to ensure the normal operation of the sensor 6. After completing the depth of the follow-up pipe drilling, the internal guiding device is withdrawn, and then the pipe orifice is sealed, and cement slurry or cement mortar is injected into the inside to increase the rigidity of the pipe-roof.

[0050] The above embodiments are only preferred embodiments given to fully illustrate the present invention, and the protection scope of the present invention is not limited thereto. Equivalent substitutions or transformations made by those skilled in the art on the basis of the present invention are all within the protection scope of the present invention.

Claims

1. A drill bit guiding system for new and old subway tunnels, comprising a drill bit (1), a drill pipe (3) and a monitoring platform, characterized in that: It further includes a connecting steel pipe (2) arranged between the drill bit (1) and the drill pipe (3). The inside of the connecting steel pipe (2) is provided with a cavity. Inside the cavity of the connecting steel pipe (2), a cylindrical mounting box (5) coaxial with the connecting steel pipe (2) is fixedly arranged. The surface of the mounting box (5) is hermetically attached to the inner wall of the connecting steel pipe (2). A spiral flow channel (4) surrounding the mounting box (5) is axially formed on the inner wall of the connecting steel pipe (2). One end of the spiral flow channel (4) is communicated with the inside of the drill pipe (3), and the other end extends to the front end of the drill bit (1). A sensor (6) is coaxially fixed inside the mounting box (5). One end of the sensor (6) close to the drill pipe (3) is connected with a signal line that penetrates through the mounting box (5) and the connecting steel pipe (2). The other end of the signal line is electrically connected to a monitoring platform. The gap between the sensor (6) and the mounting box (5) is filled with a filler (7).

2. The drill bit guiding system for a new and old subway tunnel according to claim 1, wherein: A micro cooling mechanism is provided at a position of the spiral flow channel (4) close to one end of the drill bit (1). The micro cooling mechanism includes a spring (11) and a tapered block (10) located inside the spiral flow channel (4). The diameter of the tapered block (10) gradually increases along the flowing direction of the fluid in the spiral flow channel (4). The side wall of the tapered block (10) is attached to the side wall of the spiral flow channel (4). One end of the spring (11) is fixedly connected to the large-diameter end of the tapered block (10), and the other end is fixedly connected to the inner wall of the spiral flow channel (4). The spring (11) makes the tapered block (10) have a tendency to seal the spiral flow channel (4).

3. The drill bit guiding system for new and old subway tunnels according to claim 2, characterized in that: A first air passage (12) is formed between the side wall of the spiral flow channel (4) where it is attached to the tapered block (10) and one end of the mounting box (5) close to the drill bit (1). A second air passage (14) is formed on the side wall of the mounting box (5). The second air passage (14) communicates the inside of the mounting box (5) with the first air passage (12).

4. A drill bit guiding system for new and old subway tunnels according to claim 3, characterized in that: A one-way valve (13) is arranged inside the first air passage (12).

5. A drill bit guiding system for new and old subway tunnels according to claim 3, characterized in that: A third air passage (15) is formed on the side wall of the mounting box (5) close to one end of the drill pipe (3). A fourth air passage (16) is formed on the surface of the connecting steel pipe (2) close to one end of the drill pipe (3). The third air passage (15) is used to communicate the inside of the mounting box (5) with the fourth air passage (16).

6. The drill bit guiding system for new and old subway tunnels according to claim 5, wherein: The filler (7) is made of a breathable material.

7. A drill bit guiding system for new and old subway tunnels according to claim 1, characterized in that: Radiating fins (8) are arranged on the sensor (6). The number of the radiating fins (8) is multiple, and each of the radiating fins (8) is evenly arranged on the outer surface of the sensor (6).

8. A drill bit guiding system for new and old subway tunnels according to claim 1, characterized in that: The drill bit (1) includes a drill bit body (101) and a plurality of crushing teeth (102). Each of the crushing teeth (102) is fixed on the top of the drill bit body (101), and each of the crushing teeth (102) is twisted in the clockwise or counterclockwise direction; A first chamber (103) and a second chamber (104) that are communicated with each other are arranged inside the drill bit body (101). A plurality of spraying holes (105) that are communicated with the second chamber (104) are arranged on the top of the drill bit body (101); A fifth air passage (17) is provided inside the connecting steel pipe (2), and the fifth air passage (17) communicates with the first chamber (103); the first chamber (103) has a conical structure.

9. A drill bit guiding system for new and old subway tunnels according to claim 4, characterized in that: The part of the first air passage (12) close to the spiral flow passage (4) is an air passage part, and the air passage part is distributed at an acute angle to the radial direction of the spiral flow passage (4).

10. A construction method for an extra-long pipe shed, characterized in that: The drill bit guiding system for new and old subway tunnels according to any one of claims 1-9 includes the following steps: a. Erect a pipe shed steel arch and install a guiding pipe on the steel arch. b. Move the drill rig to the position between the entrance of the new subway tunnel and the entrance of the old subway tunnel, fix and position it. First, use a down-the-hole drill to drill to the designed depth, and then use the drill bit guiding system to drill. c. Design the drilling trajectory and use the pipe-following drilling method for drilling construction. d. Use the drill bit guiding system for new and old subway tunnels to strictly control the angle of drilling, and timely correct the pipe shed steel pipes whose drilling angles exceed the allowable deviation, so that the pipe shed steel pipes are driven according to the pre-designed path. e. After each pipe shed is driven, withdraw the drill pipe and drill bit of the drilling equipment, and maintain the drill bit guiding system for new and old subway tunnels. f. Clear the holes of the pipe shed steel pipes with high-pressure air, and grout after passing the acceptance.

Images