EP3882434B1

EP3882434B1 - High-voltage pulse discharge and mechanical combined rock breaking-based novel boring machine

Info

Publication number: EP3882434B1
Application number: EP19883683.5A
Authority: EP
Inventors: Lijie Jiang; Jianbin Li; Yongliang WEN; Lianhui JIA; Fei He
Original assignee: China Railway Engineering Equipment Group Co Ltd CREG
Current assignee: China Railway Engineering Equipment Group Co Ltd CREG
Priority date: 2018-11-12
Filing date: 2019-10-08
Publication date: 2024-08-21
Anticipated expiration: 2039-10-08
Also published as: WO2020098415A1; EP3882434A1

Description

Technical Field

The present invention relates to the technical field of tunnel construction, and in particular to a novel boring machine based on combined high-voltage pulse discharge and mechanical rock breaking and a construction method therefor.

Background Art

At present, as engineering machines widely used in hard rock tunnel engineering, such as railway, hydropower, transportation, mining and municipal engineering, full-face tunnel boring machines mainly uses a rolling cutter on a rotary cutterhead to crush, shear and break rock to realize tunnel boring. But the boring efficiency of this mechanical breaking working mode is often influenced by external factors such as the rock hardness, especially under extreme conditions, so that not only the boring speed is extremely slow, but the probability of a cutter being damaged is also greatly increased, thereby causing huge economic losses to the owner and construction party. A high-voltage pulse discharge rock breaking method realizes rock breaking by means of high-voltage arc discharge between electrodes, and may control the rock breaking volume and the boring speed by adjusting parameters such as an electrode spacing and an amount of electric power input. It has the advantages of high rock breaking efficiency, low rock breaking power, low rock breaking energy consumption, no environmental pollution, etc. compared with a traditional rock breaking method, thereby having broad application prospects in the field of rock breaking. Relevant research results show that, by means of this technique, the drilling speed may be as high as 12-30 meters per hour even under geological conditions such as granite or basalt with high hardness, and the noise and vibration levels are extremely low.
A patent No. US20060037779A1 discloses a pulsed powered drilling apparatus and method. The drilling apparatus is provided comprising a bit having one or more sets of electrodes through which a pulsed voltage is passed through a mineral substrate to create a crushing or drilling action.
A second patent No. US20120103693A1 discloses a system and method for drilling a wellbore using a rotary drill bit with a bit body having a plurality of mechanical cutters to cut away formation material as the wellbore is formed; and a directed energy mechanism to direct energy into the formation. In one embodiment, directed energy members comprise a plurality of electrodes. Electrodes can be utilized in delivering electromagnetic energy against the material surrounding drill bit to break down the materials and enhance the wellbore forming capability of the drilling assembly. In this particular embodiment, electrodes are used for electrohydraulic drilling in which drill bit and directed energy mechanism are submerged in fluid. Selected electrodes are separated from a ground conductor and raised to a high-voltage until the voltage is discharged through the fluid. This produces a local fluid expansion and, hence, a pressure pulse. By applying the pressure pulse close to the formation material surrounding drill bit, the material is cracked or broken into pieces.
A third patent No. CN106979016A discloses a microwave presplitting cutterhead of a hard rock tunneling machine. Multiple microwave emitting openings are formed in the front face of the cutterhead, wave-transparent protective plates are installed on an outer end orifices, multiple microwave generating mechanisms are arranged in the cutterhead and correspond to the microwave emitting openings one to one, and the number of the microwave generating mechanisms is equal to that of the microwave emitting openings.
A fourth patent No. WO2018132979A1 discloses a laser-assisted tunnel boring machine and a rock fragmenting method thereof, which belongs to the technical field of tunnel engineering. Two rock fragmenting modes exist: a laser-cutter rock fragmenting mode and a cutter rock fragmenting mode. For the laser-assisted rock fragmenting mode, hot fragmenting is mainly performed using lasers, and laser heads are installed on a cutter head of the tunnel boring machine and are assisted by water spray systems, to achieve the purposes of auxiliary rock fragmenting by laser radiation for hot cracking and water spray for quick cooling, and mechanical rock fragmenting for excavation.
A fifth patent No. US2014327292A1 discloses a tunnel excavation device, which includes an excavation head, a main body on which the excavation head is rotatably mounted, a motor provided in the main body and rotates the excavation head, and a controller for controlling the motor, wherein the excavation head includes a perforating means formed by maintaining a predetermined interval from the center of a body part, which has a front surface formed in the shape of a circular plate, to the outer surface of the body part, an injection means for injecting water and liquid nitrogen into the hole formed by the perforating means, and a plurality of cutters provided on the surface of the main body for crushing the bedrock. According to the present invention, the perforating means such as a laser drill or the like forms a hole and water and liquid nitrogen are injected into the hole so as to crush the bedrock when the excavation work is carried out.

Summary of the Invention

In order to overcome defects in the above background art, the present invention provides a novel boring machine based on combined high-voltage pulse discharge and mechanical rock breaking, which solves the problems of low boring speed and rapid cutter wear in rock tunnel engineering in the prior art using a traditional mechanical breaking working mode.
A technical solution of the present invention is realized by a boring machine based on combined high-voltage pulse discharge and mechanical rock breaking, according to claim 1, which comprises a main boring machine and a rear accessory, wherein a cutterhead and cutter system is arranged at a front end of the main boring machine, and electrodes are arranged on the cutterhead and cutter system. The electrodes are connected to a high-voltage pulse arc control system.
The cutterhead and cutter system comprises a cutterhead body and rolling cutters, electrode scrapers and the rolling cutters are both arranged on the cutterhead body, and the cutterhead body is connected to a main drive arranged in the main boring machine. The electrodes are electrode scrapers made of an electrode material.
The rolling cutters are arranged in rows in radial directions of the cutterhead body; and each of the electrodes is arranged between two adjacent rolling cutters in the same row of rolling cutters, and a movement trajectory of the electrode coincides with a cutting trajectory of the respective rolling cutter; or the electrode is arranged between adjacent rows of rolling cutters, and the movement trajectory of the electrode is between cutting trajectories of the adjacent rows of rolling cutters.
The high-voltage pulse arc control system comprises a high-voltage pulse arc controller, and the high-voltage pulse arc controller is connected to a high-voltage power distribution station; and the electrodes are connected to the high-voltage power distribution station by means of cables, and the high-voltage power distribution station is connected to a high-voltage transformer.
The cables comprise a rotor cable and a stator cable, one end of the rotor cable being connected to the electrode and the other end thereof being connected to the stator cable by means of an electrical slip ring, and the stator cable being connected to the high-voltage power distribution station.
A main beam is provided inside the main boring machine, and is arranged parallel to a tunnel to be excavated. The main beam is provided with a support system, a front portion of the main beam is provided with a muck discharging system, and the muck discharging system is in communication with a sealed bin arranged at a rear portion of the cutterhead and cutter system.
The sealed bin is connected to a discharge medium pipeline by means of a swivel joint, and a discharge medium is introduced into the sealed bin through the discharge medium pipeline.
A rear portion of the main boring machine is provided with a shield tail sealing system, which comprises a shield tail brush arranged on an inner wall of a shield body wall and a sealing layer arranged on an outer side of a segment at a rear portion of the shield body wall.
A boring process by using the machine described above for constructing a tunnel is defined in claim 10. The process may comprise the following steps: (1) introducing a discharge medium into the sealed bin through the discharge medium pipeline, and then driving the cutterhead and cutter system to rotate by a main drive; and
(2) controlling, by a high-voltage pulse arc controller, a discharging circuit to discharge electrodes according to a rock breaking requirement, and forming a high-voltage pulse arc in the discharge medium to break rock, wherein at this moment, rolling cutters and the electrodes act on a tunnel face together to roll and scrape the rock, so as to realize combined high-voltage pulse discharge and mechanical rock breaking.
Muddy water and muck produced in a combined high-voltage pulse discharge and mechanical rock breaking process in steps (1) and (2) are stored in the sealed bin, the muddy water and the muck are mixed in the discharge medium but do not influence the discharging of the electrode, the muddy water and the muck in the sealed bin are discharged by means of the muck discharging system when reaching a certain liquid level, and the pressure inside the sealed bin and the liquid level of the discharge medium are adjusted by adjusting a muck discharging amount of the muck discharging system.
The present invention uses combined high-voltage pulse discharge and mechanical rock breaking to produce the rock breaking effect of a high-voltage pulse arc breakdown coupled with various forms such as the rolling cutters and the electrode scrapers, so that the rock breaking efficiency is improved, cutter wear is reduced, and a construction process is accelerated. The high-voltage pulse discharge control system, which is mainly composed of a high-voltage pulse arc controller, an electric energy storage device (an energy storage capacitor in a charging circuit), an electrode scraper, a high-voltage transformer, a discharge medium, etc., can damage the rock by means of the high-voltage pulse arc, for example, creating cracks, dust and spalling. It is a great innovation in tunnel boring to change the traditional rock breaking method.

Brief Description of the Drawings

In order to illustrate embodiments of the present invention more clearly, a brief introduction to the drawings required for the embodiments will be provided below. Obviously, the drawings in the following description are merely some of the embodiments of the present invention, and those of ordinary skill in the art would also have obtained other drawings according to these drawings without involving any inventive effort.

Fig. 1 is a front structural schematic diagram of the present invention in Embodiment 1;
Fig. 2 is a middle structural schematic diagram of the present invention in Embodiment 1;
Fig. 3 is a rear structural schematic diagram of the present invention in Embodiment 1;
Fig. 4 is a structural schematic diagram of a cutterhead of the present invention; and
Fig. 5 is a structural schematic diagram of a state in which rolling cutters and electrode scrapers on the cutterhead are in contact with rock.
Fig. 6 is a lower structural schematic diagram of the present invention in Embodiment 2; and
Fig. 7 is a partial enlarged schematic diagram of Fig. 6.

Detailed Description of Embodiments

The technical solutions of the embodiments of the present application will be described below clearly and comprehensively in conjunction with the drawings of the embodiments of the present invention. Obviously, the embodiments described are merely some embodiments of the present invention and are not all the possible embodiments. All the other embodiments, which are obtained by a person of ordinary skill in the art based on the embodiments of the present invention without involving any inventive effort, shall fall within the scope of protection of the present invention as defined by the appended claims.
In Embodiment 1, as shown in Fig. 1, a novel boring machine based on combined high-voltage pulse discharge and mechanical rock breaking comprises a main boring machine and a rear accessory, wherein a cutterhead and cutter system 1 is arranged at a front end of the main boring machine, electrodes 21 are arranged on the cutterhead and cutter system 1, and a high-voltage pulse arc control system is connected to the electrodes 21. The high-voltage pulse arc control system controls the discharging of the electrodes, and cooperates with rolling cutters on an existing cutterhead, to realize combined high-voltage pulse discharge and mechanical rock breaking.
Further, as shown in Figs. 4 and 5, the cutterhead and cutter system 1 comprises a cutterhead body 22 and rolling cutters 20, and the rolling cutters 20 are of a disc cutter structure commonly used for a full-face tunnel boring machine at present. The electrodes 21 are electrode scrapers made of an electrode material, the electrodes 21 are discharge electrodes which are made of a metal electrode material and are similar in shape to a scraper commonly used for the full-face tunnel boring machine at present, and the electrodes 21 have both a discharge function and a muck scraping ability. In a rock breaking process, the electrodes and the rolling cutters are brought into direct contact with rock 26. The electrode scrapers and the rolling cutters 20 are both arranged on the cutterhead body 22, the cutterhead body 22 is connected to a main drive 4 arranged in the main boring machine, and the main drive provides power for rotation of the cutterhead body.
Furthermore, as shown in Fig. 4, a plurality of electrodes 21 and a plurality of rolling cutters 20 are provided, the rolling cutters 20 are arranged in rows in radial directions of the cutterhead body 22, each row comprising a plurality of rolling cutters. Each of the electrodes 21 is arranged between two adjacent rolling cutters in the same row of rolling cutters, and a movement trajectory of the electrode 21 coincides with a cutting trajectory of the respective rolling cutter; or the electrode 21 is arranged between adjacent rows of rolling cutters, and the movement trajectory of the electrode 21 is between cutting trajectories of the adjacent rows of rolling cutters. In the present invention, the number of the electrodes 21 is preferably such that a striking range of the electrodes 21 can almost cover the whole tunnel face when the cutterhead rotates.
Further, as shown in Figs. 2 and 3, the high-voltage pulse arc control system comprises a high-voltage pulse arc controller 14, and the high-voltage pulse arc controller 14 is connected to a high-voltage power distribution station 15; and the electrodes 21 are connected to the high-voltage power distribution station 15 by means of cables, and the high-voltage power distribution station 15 is connected to a high-voltage transformer 16. In the present invention, a high-voltage pulse discharge system comprises a charging circuit, a discharging circuit and a control circuit, wherein the electrodes are part of the discharging circuit, the control circuit controls an amount of energy charged and stored during working, and then the discharging circuit releases electric energy by means of the electrodes to form an arc to break the rock. The transformer is used for increasing the voltage of an external power supply. The high-voltage pulse arc controller 14 mainly controls parameters such as the duration and frequency of the charging and discharging circuits of an energy storage capacitor of the pulse discharge system; the power distribution station 15 mainly provides electric energy for the energy storage capacitor of the pulse discharge system, the main drive, etc.; and the high-voltage transformer 16 is mainly used for increasing an external voltage to an ultra-high voltage required by the pulse discharge system and a voltage required by other circuits of the boring machine, wherein the term "high voltage" described in the present invention refers to a voltage within a range of 50-500 kV.
Further, as shown in Figs. 1 and 2, the cables comprise a rotor cable 2 and a stator cable 6, wherein one end of the rotor cable 2 is connected to the electrode 21, and the other end thereof is connected to the stator cable 6 by means of an electrical slip ring 3; the rotor cable 2 rotates along with the cutterhead body, and the rotor cable 2 rotates relative to the stator cable under the action of the electrical slip ring; and the stator cable 6 is connected to the high-voltage power distribution station 15. The high-voltage power distribution station 15 is connected to the high-voltage pulse arc controller 14 and the high-voltage transformer 16 by means of cables, and a special cable drum 17 is arranged at a rear portion of the boring machine main machine and used for collecting and winding the cables.
A main beam 12 is provided inside the main boring machine, and the main beam 12 is provided with a support system 10. When used in a shaft boring machine, the main beam is provided with a gripper system 10a, a front portion of the main beam 12 is provided with a muck discharging system 9, and the muck discharging system 9 is in communication with a sealed bin 30 arranged at a rear portion of the cutterhead and cutter system 1. A partition plate 31 is arranged on an inner side of a front portion of a shield body wall 32, and the sealed bin 30 is arranged in front of the partition plate 31, that is, the sealed bin 30 is formed by a space between the tunnel face and the partition plate; muddy water and muck produced by means of high-voltage pulse discharge rock breaking are stored in the sealed bin, that is, a soil bin, and the muddy water and the muck are mixed in a discharge medium but do not influence the discharging of the electrode; and when the muddy water and the muck in the sealed bin reach a certain liquid level, the pressure inside the sealed bin 30 and the liquid level of the discharge medium 5 are adjusted by adjusting a muck discharging amount of the muck discharging system 9, wherein the muck discharging system 9 comprises a muck discharging pump 13, and the muck discharging pump 13 pumps and discharges the muddy water and the muck out.
The sealed bin 30 is connected to a discharge medium pipeline 7 by means of a swivel joint 20, and the discharge medium 5 is introduced into the sealed bin 30 through the discharge medium pipeline 7. The discharge medium 5 is injected into the sealed bin through the discharge medium pipeline 7 to ensure that positive and negative electrodes can form high-voltage pulse discharge. The discharge medium 5 is mainly an insulating discharge material such as water, kerosene, transformer oil or other composite materials.
The discharge medium in the sealed bin 30 used in the present invention forms a necessary environment for discharge. When the electrodes conduct pulse discharge rock breaking, considering safety and other factors, the present invention has particularly strict requirements for sealing. In order to prevent the discharge medium 5 in the sealed bin 30 from passing around a shield body along an outer periphery of the shield body wall into the boring machine main machine, and to ensure the sealing performance, a rear portion of the main boring machine is provided with a shield tail sealing system, which comprises a shield tail brush 34 arranged on an inner wall of the shield body wall 32 and a sealing layer 11 arranged on an outer side of a segment 33 at a rear portion of the shield body wall 32, thereby effectively preventing the discharge medium 5 from entering the boring machine main machine. During construction, the sealing layer 11 forms a shield tail seal for a mud layer injected between the segment and a tunnel wall. In the present invention, a mud pipe storage area 18 and a water pipe drum 19 are arranged at the rear portion of the boring machine main machine. The mud pipe storage area 18 is used for storing mud, and the water pipe drum 19 is used for supporting water pipes and managing other pipelines. The present invention is further provided with a support system 10 and a thrust cylinder 8, wherein the support system 10 is used for supporting a tunnel and the thrust cylinder 8 has a propelling function in the present invention.
In Embodiment 2, a boring process by using a boring machine based on combined high-voltage pulse discharge and mechanical rock breaking comprises the following steps: (1) introducing the discharge medium into the a sealed bin through the discharge medium pipeline, and then driving the cutterhead and cutter system to rotate by a main drive; and
(2) controlling, by a high-voltage pulse arc controller, a discharging circuit to discharge electrodes according to a rock breaking requirement, and forming a high-voltage pulse arc in the discharge medium to break rock, wherein at this moment, rolling cutters and the electrodes act on a tunnel face together to roll and scrape the rock, so as to realize combined high-voltage pulse discharge and mechanical rock breaking.
Muddy water and muck produced in a combined high-voltage pulse discharge and mechanical rock breaking process in steps (1) and (2) are stored in the sealed bin, the muddy water and the muck are mixed in the discharge medium but do not influence the discharging of the electrode, the muddy water and the muck in the sealed bin are discharged by means of the muck discharging system when reaching a certain liquid level, and the pressure inside the sealed bin and the liquid level of the discharge medium are adjusted by adjusting a muck discharging amount of the muck discharging system.
The other structures are the same as those in Embodiment 1.
In a further example not defined in the claims, as shown in Figs. 6 and 7, when combined high-voltage pulse discharge and mechanical rock breaking is applied to a shaft boring machine, a shaft is internally provided with a discharge medium, with which the bottom of the shaft is filled, the discharge medium needs to submerge electrodes, and a muck discharging system is in communication with a bottom space of the shaft. The shaft boring machine also comprises a cutterhead gripper 10a and a regripping system 40, wherein the regripping system 40 realizes displacement of the whole machine by controlling expansion and contraction of a cylinder of a main beam 12, and the cutterhead gripper 10a extends out when a cutterhead rotates, and acts on a shaft wall to offset reaction torque produced due to the rotation of the cutterhead, thereby increasing strength and toughness of a system; and the shaft boring machine may not be provided with a corresponding shield tail sealing system. A boring process comprises the following steps: (1) introducing a discharge medium into the bottom of a shaft, and then driving a cutterhead and cutter system to rotate by a main driving system; and
(2) controlling, by a high-voltage pulse arc controller, a discharging circuit to discharge electrodes according to a rock breaking requirement when the cutterhead and cutter system rotates, and forming a high-voltage pulse arc in the discharge medium to break rock.
Muddy water and muck produced in a combined high-voltage pulse discharge and mechanical rock breaking process in steps (1) and (2) are stored in the sealed bin, the muddy water and the muck are mixed in the discharge medium but do not influence the discharging of the electrode, the muddy water and the muck in the sealed bin are discharged by means of the muck discharging system when reaching a certain liquid level, and the pressure inside the sealed bin and the liquid level of the discharge medium are adjusted by adjusting a muck discharging amount of the muck discharging system.
The other structures are the same as those in Embodiment 1.
The above-mentioned descriptions are merely preferred embodiments of the present invention but not intended to limit the present invention, and any modifications, equivalent replacements, improvements, etc. made within the scope of the present invention as defined by the claims are included within the scope of protection.

Claims

A boring machine based on combined high-voltage pulse discharge and mechanical rock breaking, which comprises a main boring machine and a rear accessory, wherein a cutterhead and cutter system (1) is arranged at a front end of the main boring machine, wherein
- electrodes (21) are arranged on the cutterhead and cutter system (1), and are connected to a high-voltage pulse arc control system;
characterised in that
- a sealed bin (30) is arranged at a rear portion of the cutterhead and cutter system (1):

- a muck discharging system (9) is in communication with the sealed bin (30);

- the sealed bin (30) is connected to a discharge medium pipeline (7), and a discharge medium (5) is introduced into the sealed bin (30) through the discharge medium pipeline (7).
The boring machine based on combined high-voltage pulse discharge and mechanical rock breaking according to claim 1, wherein the cutterhead and cutter system (1) comprises a cutterhead body (22) and rolling cutters (20), the electrodes (21) and the rolling cutters (20) are both arranged on the cutterhead body (22), and the cutterhead body (22) is connected to a main drive (4) arranged in the main boring machine.
The boring machine based on combined high-voltage pulse discharge and mechanical rock breaking according to claim 1 or 2, wherein the electrodes (21) are electrode scrapers made of an electrode material.
The boring machine based on combined high-voltage pulse discharge and mechanical rock breaking according to claim 3, wherein the rolling cutters (20) are arranged in rows in radial directions of the cutterhead body (22); and each of the electrodes (21) is arranged between two adjacent rolling cutters in the same row of rolling cutters, and a movement trajectory of the electrode (21) coincides with a cutting trajectory of the respective rolling cutter; or the electrode (21) is arranged between adjacent rows of rolling cutters, and the movement trajectory of the electrode (21) is between cutting trajectories of the adjacent rows of rolling cutters.
The boring machine based on combined high-voltage pulse discharge and mechanical rock breaking according to claim 1 or 4, wherein the high-voltage pulse arc control system comprises a high-voltage pulse arc controller (14), and the high-voltage pulse arc controller (14) is connected to a high-voltage power distribution station (15); and the electrodes (21) are connected to the high-voltage power distribution station (15) by means of cables, and the high-voltage power distribution station (15) is connected to a high-voltage transformer (16).
The boring machine based on combined high-voltage pulse discharge and mechanical rock breaking according to claim 5, wherein the cables comprise a rotor cable (2) and a stator cable (6), one end of the rotor cable (2) being connected to the electrode (21) and the other end thereof being connected to the stator cable (6) by means of an electrical slip ring (3), and the stator cable (6) being connected to the high-voltage power distribution station (15).
The boring machine based on combined high-voltage pulse discharge and mechanical rock breaking according to claim 1 or 6, wherein a rear portion of the main boring machine is provided with a shield tail sealing system, which comprises a shield tail brush (34) arranged on an inner wall of a shield body wall (32) and a sealing layer (11) arranged on an outer side of a segment (33) at a rear portion of the shield body wall(32).
The boring machine based on combined high-voltage pulse discharge and mechanical rock breaking according to claim 1 or 6, wherein a main beam (12) is provided inside the main boring machine, the main beam (12) is arranged parallel to a tunnel to be excavated, the main beam (12) is provided with a support system (10), a front portion of the main beam (12) is provided with the muck discharging system (9) .
The boring machine based on combined high-voltage pulse discharge and mechanical rock breaking according to any one of preceding claims, wherein the sealed bin (30) is connected to a discharge medium pipeline (7) by means of a swivel joint (20).
A boring process by using the boring machine based on combined high-voltage pulse discharge and mechanical rock breaking according to any of claims 1 to 9 for constructing a tunnel.
The boring process according to claim 10, comprising the following steps: (1) introducing the discharge medium (5) into the sealed bin (30) through the discharge medium pipeline (7), and then driving the cutterhead and cutter system (1) to rotate by a main drive (4); and
(2) controlling, by a high-voltage pulse arc controller (14), a discharging circuit to discharge electrodes (21) according to a rock breaking requirement, and forming a high-voltage pulse arc in the discharge medium (5) to break rock, wherein at this moment, rolling cutters (20) and the electrodes (21) act on a tunnel face together to roll and scrape the rock, so as to realize combined high-voltage pulse discharge and mechanical rock breaking.
The boring process according to claim 11, wherein muddy water and muck produced in a combined high-voltage pulse discharge and mechanical rock breaking process in steps (1) and (2) are stored in the sealed bin, the muddy water and the muck are mixed in the discharge medium (5) but do not influence the discharging of the electrode (21), the muddy water and the muck in the sealed bin (30) are discharged by means of the muck discharging system (9) when reaching a certain liquid level, and the pressure inside the sealed bin (30) and the liquid level of the discharge medium (5) are adjusted by adjusting a muck discharging amount of the muck discharging system (9).