An auxiliary system for improving the efficiency of electric pulse rock breaking

Abstract

The application relates to an auxiliary system for improving the efficiency of electric pulse rock breaking, which comprises an electric pulse generator, a high-voltage electrode, a grounding electrode, an insulating medium, rock and a liquid medium, a strong magnetic source is arranged between the high-voltage electrode and the grounding electrode, the strong magnetic source is infinitely close to the top surface of the rock and does not contact the rock, the direction of electric pulse rock breaking is adjusted by changing the distance between the strong magnetic source and the high-voltage electrode, the direction of the magnetic field lines of the magnetic field of the strong magnetic source and the electric field formed between the high-voltage electrode and the grounding electrode is adjusted through pulse voltage, and then the electromagnetic force along the direction of the rock interior exists in the region where the plasma is to be grown; the magnetic field strength generated by the strong magnetic source is increased to change the growth path of the plasma channel in the rock and the liquid medium in the electric pulse rock breaking electric breakdown process, and the overall plasma channel length is increased. The application can realize relatively high rock breaking efficiency without making great changes to the original electric pulse rock breaking method, and the application scope is flexible, and the rock breaking direction is controllable.

Description

Technical Field

[0001] This invention belongs to the field of electric pulse rock breaking technology, specifically relating to an auxiliary system for improving the efficiency of electric pulse rock breaking. Background Technology

[0002] Electric pulse rock breaking has advantages such as high efficiency and environmental friendliness, and its rock breaking mode is crucial to its efficiency. High-voltage electric pulse rock breaking modes are divided into electric rock breaking and liquid-electric rock breaking. Under instantaneous high-voltage pulse voltage, when the pulse voltage rise time is short (rise time < 500 ns), the liquid medium has low conductivity (e.g., deionized water with conductivity less than 60 μS / m), and the rock is in close contact with the electrode, the electrical breakdown field strength of the rock is less than that of the liquid medium. The discharge plasma channel is mainly generated inside the rock, and the driving force for rock breaking comes from the shock wave stress generated when the plasma channel expands. This mode is called electric rock breaking. Conversely, when the pulse voltage rise time is long, or the liquid medium has high conductivity, or the rock is not in direct contact with the electrode, the discharge plasma channel is mainly generated in the liquid medium. The shock wave generated by the collapse of bubbles and high-speed water flow in the liquid medium acts on the rock surface, resulting in liquid-electric rock breaking. Current research suggests that electric rock breaking is more efficient than liquid-electric rock breaking.

[0003] Previous studies on electric pulse rock breaking have shown that pulse voltage and electrode spacing are positively correlated with electric pulse rock breaking efficiency, and there is a matching relationship between pulse voltage and electrode spacing. On the other hand, the rock breaking effect of electric pulses largely depends on the growth path of the plasma channel. Under the same conditions, the greater the longitudinal penetration depth of the plasma channel, the larger the rock-breaking volume per unit energy consumption of the electric pulse, and the higher the rock breaking efficiency. Therefore, the longitudinal expansion capability of the plasma channel can be enhanced by controlling influencing factors to increase rock breaking efficiency.

[0004] Existing research has shown that changes in magnetic fields significantly influence the formation of plasma channels within rocks. Under an applied magnetic field, plasma channels gradually tend to "downward" (develop within the rock), and the temperature distribution within these channels becomes more concentrated. In the presence of a magnetic field, the velocity and degrees of freedom of charged particles are restricted. Under an external magnetic field, fewer charged particles deviate, resulting in a downward accumulation of particles. Therefore, strong magnetic-assisted electric pulse rock breaking can increase the longitudinal penetration of plasma channels and improve the efficiency of electric pulse rock breaking. Summary of the Invention

[0005] The purpose of this invention is to provide an auxiliary system for improving the efficiency of electric pulse rock breaking. This system adds an internal magnetic field to the existing electric pulse rock breaking system, thereby improving the efficiency of electric pulse rock breaking.

[0006] To achieve the above objectives, the present invention adopts the following technical solution:

[0007] An auxiliary system for improving the efficiency of electric pulse rock breaking includes an electric pulse generator, a high-voltage electrode, a grounding electrode, an insulating medium, rock, and a liquid medium. The positive and negative terminals of the electric pulse generator are connected to the high-voltage electrode and the grounding electrode, respectively. The outer sides of the high-voltage electrode and the grounding electrode are covered with an insulating medium. The bottoms of the high-voltage electrode and the grounding electrode are in contact with the top of the rock. The interior of the rock between the high-voltage electrode and the grounding electrode is a plasma growth zone. The rock, the high-voltage electrode, and the grounding electrode are all located in the liquid medium. The working liquid medium provides a liquid environment with a conductivity of less than 60 μS / m for rock breaking.

[0008] A strong magnetic source is provided between the high-voltage electrode and the grounding electrode. The strong magnetic source is infinitely close to the top surface of the rock but does not make contact. The direction of the electric pulse breaking the rock is changed by changing the distance between the strong magnetic source and the high-voltage electrode. The intensity of the strong magnetic source is greater than the critical magnetic field adaptation value. The action time is the time it takes for the plasma channel to completely penetrate to both ends of the electrode.

[0009] By adjusting the direction of the electric field and the magnetic field line of the strong magnetic source formed between the high-voltage electrode and the ground electrode by pulse voltage, an electromagnetic force along the internal direction of the rock is formed in the plasma growth area; increasing the magnetic field strength generated by the strong magnetic source changes the growth path of the plasma channel in the rock and liquid medium during the electric pulse rock breaking and electrical breakdown process, and increases the overall plasma channel length.

[0010] Changing the spatial position of the strong magnetic source or the direction of the magnetic field lines of the strong magnetic source enables the directional control and adjustment of the electric pulse rock breaking.

[0011] Furthermore, the width of the plasma growth region is the straight-line distance between the high-voltage electrode and the ground electrode, and its longitudinal depth and thickness increase as the peak value of the pulse voltage increases.

[0012] Furthermore, the method for obtaining the critical magnetic field adaptation value is as follows: control the magnetic field strength of the strong magnetic source to increase sequentially from zero, and record the peak voltage of a specific pulse, the distance between the high-voltage electrode and the ground electrode, the longitudinal distance of the strong magnetic source, the lateral distance between the strong magnetic source and the high-voltage electrode, and the equivalent fracture volume or fracture volume of the rock; the fracture volume of the rock domain increases by a certain value when there is a strong magnetic field strength compared to when there is no strong magnetic source, and the corresponding magnetic field strength is taken as the critical magnetic field adaptation value under the specific parameter.

[0013] Furthermore, the strong magnetic source is a permanent magnetic source or a pulsed magnetic source.

[0014] Furthermore, when the high-voltage electrode and grounding electrode of the electric pulse rock breaking tool are not in direct contact with the rock, or when the conductivity of the working fluid medium increases, or when the rise time of the instantaneous pulse voltage provided by the electric pulse generator is greater than 500ns, or when the pulse voltage provided by the electric pulse generator does not reach the breakdown voltage of the rock, the hydraulic-electric rock breaking mode is used to improve the rock breaking efficiency.

[0015] Furthermore, there are four grounding electrodes and four strong magnetic sources. The high-voltage electrode is located on the rock axis. There are four branch electrodes at the bottom of the grounding electrode, which are evenly distributed circumferentially on the outermost side of the electric pulse rock breaking tool. An insulating medium is filled between the high-voltage electrode and the grounding electrode. The strong magnetic source is covered by the insulating medium and installed between the high-voltage electrode and the grounding electrode. It is also evenly distributed circumferentially between the high-voltage electrode and the grounding electrode and the four branch electrodes of the grounding electrode.

[0016] Compared with existing electric pulse rock breaking methods, this invention can achieve relatively high rock breaking efficiency without making significant changes to the original electric pulse rock breaking methods, and it has a flexible range of applications and controllable rock breaking direction. Attached Figure Description

[0017] Figure 1 This is a schematic diagram of the system composition of the present invention.

[0018] Figure 2 The influence of the positional relationship of the strong magnetic source on the rock-breaking efficiency in this invention. Figure 1 .

[0019] Figure 3 The influence of the positional relationship of the strong magnetic source on the rock-breaking efficiency in this invention. Figure 2 .

[0020] Figure 4 The influence of the positional relationship of the strong magnetic source on the rock-breaking efficiency in this invention. Figure 3 .

[0021] Figure 5 This illustrates the parameter matching relationship between the strong magnetic field parameters and the electric field parameters of this invention.

[0022] Figure 6 This is a schematic diagram of an embodiment 2 of the present invention where the electrode does not contact the rock.

[0023] Figure 7 This is a schematic diagram of the electrode arrangement in Embodiment 3 of the present invention.

[0024] The diagram is labeled as follows: 1. Electric pulse generator; 2. High voltage electrode; 3. Grounding electrode; 23. Electric field lines; 4. Insulating medium; 5. Strong magnetic source; 5-1. Magnetic field lines; 5-11. Magnetic field lines pointing out of the plane; 5-12. Magnetic field lines pointing in the plane; 5-2. South (S) pole of strong magnetic source; 5-3. North (N) pole of strong magnetic source; 6. Rock; 6-1. Plasma growth area; 7. Liquid medium; 8. Plasma channel. Detailed Implementation

[0025] Example 1

[0026] like Figure 1 As shown in the figure, this embodiment provides an auxiliary system for improving the efficiency of electric pulse rock breaking. The system adds an internal strong magnetic source 5 to the electric pulse rock breaking system to improve the rock breaking efficiency.

[0027] The electric pulse rock-breaking system includes an electric pulse generator 1, a high-voltage electrode 2, a grounding electrode 3, an insulating medium 4, rock 6, and a liquid medium 7. The positive and negative terminals of the electric pulse generator 1 are connected to the high-voltage electrode 2 and the grounding electrode 3, respectively. The outer sides of both the high-voltage electrode 2 and the grounding electrode 3 are covered with the insulating medium 4. A plasma growth region 6-1 is formed on the top of the rock 6. The ends of the high-voltage electrode 2 and the grounding electrode 3 are in contact with the tops of both sides of the plasma growth region 6-1. The rock 6, the high-voltage electrode 2, and the grounding electrode 3 are all located in the liquid medium 7, which provides a liquid environment with a conductivity of less than 60 μS / m for rock breaking. In this embodiment, a strong magnetic source 5 is provided between the high-voltage electrode 2 and the grounding electrode 3. The electric pulse generator 1 provides a rising edge of <500 ns and a pulse voltage peak value of U. p The instantaneous pulse voltage; by adjusting the pulse voltage, an electric field is formed between the high-voltage electrode 2 and the ground electrode 3, and the direction of the magnetic field line 5-1 of the strong magnetic source 5 is formed, thereby making an electromagnetic force exist in the plasma growth region 6-1 along the direction inside the rock 6; the magnetic field strength generated by the strong magnetic source 5 is increased, which changes the growth path of the plasma channel 8 in the rock 6 and the liquid medium during the electric pulse rock breaking and electrical breakdown process, and increases the overall length of the plasma channel 8.

[0028] The greater the longitudinal penetration depth of the plasma channel 8 inside the rock 6, the larger the initial damage range inside the rock 6; the greater the length of the plasma channel 8 inside the liquid medium, the greater the channel impedance inside the liquid medium, and the greater the shock wave generated by the electrohydraulic effect on the surface of the rock 6; the initial damage range inside the rock 6 and the electrohydraulic impact force acting on the surface of the rock 6 work together to ultimately improve the efficiency of electric pulse rock breaking.

[0029] Let the width of the plasma growth region 6-1 be L. s That is, the distance between the high-voltage electrode 2 and the grounding electrode 3 is L. sThe longitudinal depth of the plasma growth region 6-1 is 0.33–0.5 L. s The thickness of the plasma growth region 6-1 is 0.33–0.5 L. s The distance between the strong magnetic source 5 and the high-voltage electrode 2 is l. c The vertical distance from the ends of the high-voltage electrode 2 and the grounding electrode 3 is h. c ; Change the spatial position of the strong magnetic source 5 (the longitudinal distance h of the strong magnetic source 5) c Lateral distance l between strong magnetic source 5 c The direction of electric pulse rock breaking can be controlled and adjusted by the magnetic field line 5-1 of the strong magnetic source 5.

[0030] Strong magnetic source 5 lateral distance l c For L s At / 2, the longitudinal distance h of the strong magnetic source 5 c The closer to 0, the better the efficiency of electric pulse rock breaking; the better the electric pulse rock breaking direction is away from the rock surface.

[0031] The longitudinal distance h of the strong magnetic source 5 c When the distance between the strong magnetic source 5 and the high-voltage electrode 2 is constant, the closer the electric pulse rock-breaking direction is to the high-voltage electrode 2, and |L s / 2-h c The larger the value, the greater the deviation of the rock-breaking direction of the electric pulse towards the high-voltage electrode 2; conversely, the smaller the value, the greater the lateral distance l of the strong magnetic source 5. c Greater than L s At / 2, the closer the strong magnetic source 5 is to the grounding electrode 3, the more the rock-breaking direction of the electric pulse deviates towards the grounding electrode 3, and |L s / 2-h c The larger the value, the greater the deviation of the rock-breaking direction of the electric pulse from the grounding electrode 3.

[0032] This embodiment uses experimental simulation to determine the width L of the plasma growth region 6-1. s =20mm, the longitudinal depth and thickness of the plasma growth region 6-1 are both 10mm, ignoring the size of the strong magnetic source 5, it is assumed that the strong magnetic source 5 is a point, and the intensity of the strong magnetic source 5 is B=5T, such as Figure 2 As shown, l c =5mm, h c Take 1mm, 5mm, 10mm, 15mm, and 20mm, when h c The efficiency of electric pulse rock breaking is best when the thickness is 1mm; for example, Figure 3 As shown, l c =10mm, h c Take 1mm, 5mm, 10mm, 15mm, and 20mm, when h c The efficiency of electric pulse rock breaking is best when the thickness is 1mm; for example, Figure 4 As shown, l c =15mm, h c Take 1mm, 5mm, 10mm, 15mm, and 20mm, when h c The efficiency of electric pulse rock breaking is best when the distance is 1 mm. Therefore, the closer the strong magnetic source 5 is to the top surface of the plasma growth area, the better the efficiency of electric pulse rock breaking.

[0033] In this embodiment, the optimal solution is that the longitudinal distance of the strong magnetic source 5 is h. c =1mm, the lateral distance is controlled and adjusted according to the direction of the electric pulse rock breaking.

[0034] The longitudinal depth and thickness of the plasma growth region 6-1 should be determined based on the peak pulse voltage U. p Size and rock type 6 adjustment, pulse voltage peak U p The larger the rock 6 or the smaller the electrical breakdown strength of the rock 6, the easier it is to break down the rock 6, and the longitudinal depth and thickness of the plasma growth region 6-1 will increase accordingly.

[0035] The magnitude B of the magnetic field strength of the strong magnetic source 5 is related to the type of rock 6 and the electrode spacing L. s Pulse voltage peak U p Parameters of strong magnetic field generation location (longitudinal distance h of strong magnetic source 5) c Lateral distance l between strong magnetic source 5 c There is a compatibility between them. Simulation experiments show that the magnitude of the magnetic field strength B must be greater than the critical magnetic field compatibility value B. cr .

[0036] The critical magnetic field adaptation value B cr The method for obtaining it is as follows:

[0037] Conduct pulsed discharge rock-breaking experiments or simulations on specific rock type 6, control the magnetic field strength B of strong magnetic source 5 to increase sequentially from zero, and record the peak voltage U of specific pulses sequentially. p Electrode spacing L s 5. Longitudinal distance h of strong magnetic source c Lateral distance l between strong magnetic source 5 c The equivalent or fractured volume of a specific rock domain 6; the fractured volume of this rock domain 6 increases by a certain value when the magnetic field strength of the strong magnetic source 5 is present compared to when the strong magnetic source 5 is absent, and this value is selected within the range of 5% to 50%; the corresponding magnetic field strength is used as this specific parameter (i.e., the pulse peak voltage U). p Electrode spacing L s Longitudinal distance h of strong magnetic source 5 c Lateral distance l between strong magnetic source 5 c Critical magnetic field fit value B under fixed conditions cr .

[0038] The strong magnetic source 5 is either a permanent magnetic source or a pulsed magnetic source; the duration of the magnetic field strength of the strong magnetic source 5 must include the time from the start of the pulse voltage rise to the point where the plasma channel 8 is fully penetrated to both ends of the electrode, i.e., t ≥ t cr ,like Figure 5 As shown, t cr For the plasma channel 8 to fully penetrate to both ends of the electrodes, the magnitude of its magnetic field strength must be greater than or equal to specific parameters (i.e., rock type 6, pulse peak voltage U). p Electrode spacing L s Longitudinal distance h of strong magnetic source 5 c Lateral distance l between strong magnetic source 5 c Critical magnetic field fit value B under fixed conditions cr That is, B≥B cr (t∈[0,t cr The moment t when plasma channel 8 is fully penetrated to both ends of the electrodes. cr The value of the pulse current is determined to rise to the critical current I. cr At the corresponding moment, the voltage is the critical voltage U. cr Critical current I cr The range is 0.5 to 1.0 kA; the magnetic field strength curve ABCD of the strong magnetic source 5 must be above and to the right of the gray rectangle oabc.

[0039] The component of the electromagnetic force generated in the plasma growth region 6-1 by the electric field formed between the high-voltage electrode 2 and the ground electrode 3, under the action of the magnetic field lines 5-1 generated by the strong magnetic source 5, is the component along the interior direction of the rock 6.

[0040] The electric field is directed from the high-voltage electrode 2 to the ground electrode 3; the magnetic field line 5-1 is directed from the north (N) pole to the south (S) pole; the electric field, the magnetic field line 5-1, and the electromagnetic force generated in the plasma growth region 6-1 follow the left-hand rule, that is, the left palm is flat, the magnetic field line 5-1 is directed from the north (N) pole to the south (S) pole and passes through the palm, the fingertips are along the direction of the electric field, and the direction pointed by the tip of the thumb, which is perpendicular to the four fingers, is the direction of the electromagnetic force.

[0041] Example 2

[0042] This embodiment is basically the same as Embodiment 1, except that the high-voltage electrode 2 and the grounding electrode 3 do not directly contact the rock 6; their ends are located on the top surface of the plasma growth region. Figure 6 As shown, the strong magnetic source 5 is located between the high-voltage electrode 2 and the grounding electrode 3, with a longitudinal distance h. c It is 1mm.

[0043] The instantaneous pulse voltage generated by the electrical pulse generator 1 (rising edge <500ns, peak value U)p The electric field acts on both ends of the high-voltage electrode 2 and the grounding electrode 3. Under the influence of the electric field, the rock 6 gradually breaks down, forming a plasma channel 8, and the pulse voltage gradually decreases. At the same time, the magnetic field strength B generated by the strong magnetic source 5 also acts simultaneously; the magnetic field strength generated by the strong magnetic source 5 generates magnetic field lines 5-11 pointing outward in the plasma growth region 6-1 within the rock 6 (such as...). Figure 6 (as shown in a); the electric field generated by the high-voltage electrode 2 and the ground electrode 3 is roughly from left to right. According to the left-hand rule, with the fingertips of the left hand pointing from left to right and the palm facing the plane, the plasma channel 8 is subjected to a vertically downward electromagnetic force during the electric pulse rock breaking process, and the plasma channel 8 extends into the depth.

[0044] Until a certain moment, the pulse current reaches the critical current I. cr At this point, the voltage drops to the critical voltage U. cr Plasma channel 8 extends completely through the electrodes at both ends, such as Figure 6 As shown in diagram a. Then, the charge in the electric pulse generator 1 is rapidly injected into the rock 6, causing the circuit current to rise rapidly and reach its peak current I. p The voltage at the electrode rapidly decreases until it approaches zero. After the plasma channel 8 is formed, the conductivity inside the rock 6 increases dramatically, and the charge in the circuit is rapidly injected into the plasma channel 8. The temperature inside the plasma channel 8 rises rapidly, its volume expands and acts on the surrounding rock 6, ultimately causing the rock 6 to break or fracture.

[0045] Figure 6 By adjusting the lateral distance l of the strong magnetic source 5 c On the side closer to the high-voltage electrode 2, the generated plasma channel 8 shifts to the left. Through repeated pulse action, the rock-breaking direction is thus controlled to the left.

[0046] The high-voltage electrode 2 and grounding electrode 3 of the electric pulse rock-breaking tool can directly contact the rock 6 to complete rock breaking through the electric rock-breaking mode; when the high-voltage electrode 2 and grounding electrode 3 of the electric pulse rock-breaking tool are not in direct contact with the rock 6, or the conductivity of the working liquid medium 7 increases, or the rise time of the instantaneous pulse voltage provided by the electric pulse generator 1 is greater than 500ns, or the pulse voltage provided by the electric pulse generator 1 does not reach the breakdown voltage of the rock 6, the hydraulic-electric rock-breaking mode can also be used to improve the rock-breaking efficiency.

[0047] Example 3

[0048] This embodiment improves upon embodiment 2 by increasing the number of grounding electrodes 3 and the number of strong magnetic sources 5, while maintaining the same number of both. This embodiment uses four grounding electrodes 3 and four strong magnetic sources 5 as an example. Figure 7As shown, the high-voltage electrode 2 is located at the axis of the rock-breaking system; the grounding electrode 3 has four branch electrodes at its bottom, evenly distributed circumferentially on the outermost side of the electric pulse rock-breaking tool; the insulating medium 4 is made of polytetrafluoroethylene and fills the space between the high-voltage electrode 2 and the grounding electrode 3; the electric pulse generator 1 provides the rock-breaking tool with a rising edge of <500ns and a pulse voltage peak value of U. p The instantaneous pulse voltage; the working liquid medium 7 is deionized water, which provides a liquid environment with a conductivity of less than 60 μS / m for rock breaking.

[0049] The strong magnetic source 5 uses four permanent magnetic sources, neodymium iron boron magnets (N52), which are encased in an insulating medium 4 and installed between the high-voltage electrode 2 and the grounding electrode 3. The four branch electrodes of the grounding electrode 3 are evenly distributed circumferentially between the high-voltage electrode 2 and the grounding electrode 3 in the electric pulse rock-breaking tool. Figure 7 As shown in b. The magnetic field strength of the four strong magnetic sources 5 is basically constant, so the duration of action can satisfy the requirement of including the time from the start of the pulse voltage rise to the time when the plasma channel 8 is completely penetrated to both ends of the electrode.

[0050] The rock-breaking process is as follows: First, the instantaneous pulse voltage generated by the electric pulse generator 1 (rising edge <500ns, peak value U) p The electric field acts on both ends of the high-voltage electrode 2 and the grounding electrode 3 of rock 6. Then, under the influence of the electric field, the interior of rock 6 gradually breaks down, forming a plasma channel 8, and the pulse voltage gradually decreases. Simultaneously, the magnetic field strength B generated by the strong magnetic source 5 also acts; as... Figure 7 As shown on the left, the strong magnetic source 5 generates magnetic field lines 5-12 pointing inward within the plasma growth region 6-1 in the rock 6; the electric fields generated by the high-voltage electrode 2 and the grounding electrode 3 are roughly from right to left. According to the left-hand rule, with the fingertips pointing from right to left and the back of the hand facing the plane, the plasma channel 8 experiences a downward electromagnetic force during the electric pulse rock-breaking process, causing the plasma channel 8 to extend deeper; similarly, as... Figure 7 As shown on the left side (b), the strong magnetic source 5 generates magnetic field lines 5-11 pointing outward within the plasma growth region 6-1 in the rock 6; the electric fields generated by the high-voltage electrode 2 and the grounding electrode 3 are roughly from left to right. According to the left-hand rule, with the fingertips pointing from left to right and the palm facing the plane, the plasma channel 8 is subjected to a downward electromagnetic force during the electric pulse rock breaking process, causing the plasma channel 8 to extend deeper.

[0051] Until a certain moment, the pulse current reaches the critical current I. cr At this point, the voltage drops to the critical voltage U. cr Plasma channel 8 extends completely through the electrodes at both ends, such as Figure 7As shown in diagram a. Then, the charge in the electric pulse generator 1 is rapidly injected into the rock 6, causing the circuit current to rise rapidly and reach its peak current I. p The voltage at the electrode rapidly decreases until it approaches zero. After the plasma channel 8 is formed, the conductivity inside the rock 6 increases dramatically, and the charge in the circuit is rapidly injected into the plasma channel 8. The temperature inside the plasma channel 8 rises rapidly, its volume expands and acts on the surrounding rock 6, ultimately causing the rock 6 to break or fracture.

[0052] This embodiment mainly utilizes the direct contact between the high-voltage electrode 2 and the grounding electrode 3 of the electric pulse rock-breaking tool and the rock 6 to improve rock-breaking efficiency through the electric rock-breaking mode. However, when the high-voltage electrode 2 and the grounding electrode 3 of the electric pulse rock-breaking tool are not in direct contact with the rock 6, or when the conductivity of the working fluid medium 7 increases, or when the rise time of the instantaneous pulse voltage provided by the electric pulse generator 1 is greater than 500ns, or when the pulse voltage provided by the electric pulse generator 1 does not reach the breakdown voltage of the rock 6, the hydraulic-electric rock-breaking mode can also be used to improve rock-breaking efficiency through the above methods. The specific efficiency improvement principle is that by adjusting the direction of the electric field formed between the high-voltage electrode 2 and the grounding electrode 3 and the direction of the magnetic field line 5-1 of the strong magnetic source 5, an electromagnetic force is generated in the plasma growth region 6-1 along the internal direction of the rock 6. Overall, both the length of the plasma channel 8 inside the rock 6 and the length of the plasma channel 8 inside the rock 6 are increased. In particular, the increase in the length of the plasma channel 8 inside the liquid medium increases the channel impedance inside the liquid medium, and the shock wave generated by the electrohydraulic effect on the surface of the rock 6 is also increased accordingly, thus improving the rock breaking efficiency. The increase in the longitudinal penetration depth of the plasma channel 8 inside the rock 6 increases the initial damage range inside the rock 6, ultimately improving the efficiency of electric pulse rock breaking.

[0053] The above description is only a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any modifications and substitutions based on the technical solutions and inventive concepts provided by the present invention should be covered within the scope of protection of the present invention.

Claims

1. An auxiliary system for improving the efficiency of electric pulse rock breaking, comprising an electric pulse generator, a high-voltage electrode, a grounding electrode, an insulating medium, rock, and a liquid medium. The positive and negative poles of the electric pulse generator are respectively connected to the high-voltage electrode and the grounding electrode. The outer sides of the high-voltage electrode and the grounding electrode are covered with an insulating medium. The bottoms of the high-voltage electrode and the grounding electrode are in contact with or not in contact with the top of the rock. The interior of the rock between the high-voltage electrode and the grounding electrode is a plasma growth zone. The rock, the high-voltage electrode, and the grounding electrode are all located in the liquid medium, which provides a liquid environment with an electrical conductivity of less than 60 μS / m for rock breaking. Its features are: A strong magnetic source is provided between the high-voltage electrode and the ground electrode. The strong magnetic source is infinitely close to the top surface of the rock but does not make contact. The direction of the electric pulse breaking the rock is adjusted by changing the distance between the strong magnetic source and the high-voltage electrode. The intensity of the strong magnetic source is greater than the critical magnetic field adaptation value. The action time must include the time from when the pulse voltage begins to rise to when the plasma channel is completely penetrated to both ends of the electrode. Adjusting the direction of the electric field and the magnetic field line of the strong magnetic source formed between the high-voltage electrode and the ground electrode, so that electromagnetic force is generated in the plasma growth area along the direction of the rock interior; increasing the magnetic field strength generated by the strong magnetic source changes the growth path of the plasma channel in the rock and liquid medium during the electric pulse rock breaking and electrical breakdown process, and increases the overall plasma channel length. Changing the spatial position of the strong magnetic source or the direction of the magnetic field lines of the strong magnetic source enables the directional control and adjustment of the electric pulse rock breaking.

2. The auxiliary system for improving the efficiency of electric pulse rock breaking according to claim 1, characterized in that, The width of the plasma growth region is the straight-line distance between the high-voltage electrode and the ground electrode, and its longitudinal depth and thickness increase as the peak value of the pulse voltage increases.

3. The auxiliary system for improving the efficiency of electric pulse rock breaking according to claim 1, characterized in that, The method for obtaining the critical magnetic field adaptation value is as follows: control the magnetic field strength of the strong magnetic source to increase sequentially from zero, and record the peak voltage of a specific pulse, the distance between the high voltage electrode and the ground electrode, the longitudinal distance of the strong magnetic source, and the lateral distance between the strong magnetic source and the high voltage electrode. The volume of rock fragmentation increases by a certain value when there is a strong magnetic source compared to when there is no strong magnetic source. The corresponding magnetic field strength is taken as the critical magnetic field adaptation value under this specific parameter.

4. The auxiliary system for improving the efficiency of electric pulse rock breaking according to claim 1, characterized in that, The strong magnetic source is either a permanent magnetic source or a pulsed magnetic source.

5. The auxiliary system for improving the efficiency of electric pulse rock breaking according to claim 1, characterized in that, When the high-voltage electrode and grounding electrode of the electric pulse rock breaking tool are not in direct contact with the rock, or when the conductivity of the working fluid medium increases, or when the rise time of the instantaneous pulse voltage provided by the electric pulse generator is greater than 500ns, or when the pulse voltage provided by the electric pulse generator does not reach the breakdown voltage of the rock, the efficiency of rock breaking can be improved by using electrohydraulic rock breaking.

6. The auxiliary system for improving the efficiency of electric pulse rock breaking according to claim 5, characterized in that, There are four grounding electrodes and four strong magnetic sources. The high-voltage electrode is located on the rock axis. There are four branch electrodes at the bottom of the grounding electrode, which are evenly distributed circumferentially on the outermost side of the electric pulse rock breaking tool. The insulating medium is filled between the high-voltage electrode and the grounding electrode. The strong magnetic source is covered by the insulating medium and installed between the high-voltage electrode and the grounding electrode. It is evenly distributed circumferentially between the high-voltage electrode and the grounding electrode and the four branch electrodes of the grounding electrode.

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