Jet breaking hard rock device and method based on dynamic thermal-mechanical coupling

Abstract

The invention provides a jet breaking hard rock device and method based on dynamic thermal-mechanical coupling, and the method comprises a microwave pre-damage stage: heating to-be-broken rock through high-frequency microwave targeted irradiation, collecting the surface temperature field change of the to-be-broken rock in real time, generating a jet trigger signal when the temperature field reaches a preset thermal damage threshold value, and sending the jet trigger signal to the microwave pre-damage stage; meanwhile, microwave irradiation termination is triggered; a jet flow impact stage: after receiving the jet flow trigger signal, starting a multi-mode jet flow generation module in a preset time window, and adaptively selecting an abrasive jet flow mode or a pure water jet flow mode according to the quartz content data to apply hot and cold circulation jet flow impact to the surface of the rock to be crushed; and a vaporization expansion stage: synchronously applying intermittent microwave irradiation in the jet flow impact process, so that water injected into rock cracks through jet flow impact is heated, vaporized and pressurized, and the cracks in the rock are driven to expand autonomously. Through the synergistic effect of the three stages of microwave pre-damage, jet flow impact and vaporization expansion, high-efficiency and low-energy-consumption crushing of hard rocks is achieved.

Description

Technical Field

[0001] The present invention relates to the technical field of rock breaking, and particularly relates to a jet rock-breaking device and method based on dynamic thermal-mechanical coupling. Background Art

[0002] Traditional hard rock breaking methods (such as mechanical drilling and explosive blasting) have problems such as low efficiency, high energy consumption, and poor environmental adaptability. Although existing jet rock-breaking technologies can reduce mechanical wear, a single jet mode is difficult to adapt to complex rock masses, and traditional methods overly rely on mechanical impact damage and lack the utilization of a thermal-mechanical synergistic mechanism.

[0003] Currently, microwave rock-breaking technology has emerged. The essence of microwave rock-breaking lies in exciting the dipole polarization effect of polar molecules (such as quartz crystal SiO2) in rocks through high-frequency electromagnetic waves, triggering intermolecular friction to generate heat and a drastic change in local temperature gradient. In the microwave pre-damage stage, mineral particles generate a non-uniform thermal stress field due to differences in expansion coefficients: highly microwave-absorbing minerals such as quartz expand upon heating to form compressive stress, and when it exceeds the interfacial bonding strength of the minerals, a thermally induced crack network is generated; subsequently, in the jet impact stage, the cold medium (20 - 30°C) of an ultra-high-pressure water jet or abrasive jet contacts the surface of the high-temperature rock (300 - 400°C), triggering a thermal shock tensile stress and promoting the propagation and penetration of microcracks along grain boundaries.

[0004] The invention patent application with publication number CN112796664A discloses a drilling device and method for microwave-assisted supercritical carbon dioxide jet, which reduces rock strength through the coupling of microwave and supercritical carbon dioxide jet. However, this technology has the following significant defects: 1) Supercritical carbon dioxide needs to maintain a critical state (temperature > 31°C, pressure > 7.38 MPa), resulting in an increase in the energy consumption of the jet system, and the phase change control accuracy requirement is harsh, which easily causes gas-liquid two-phase flow disorder; 2) The carbon dioxide jet lacks the mechanical grinding effect of an abrasive medium, and the rock-breaking efficiency for rocks with a high quartz content (harder rocks) is relatively low.

[0005] The invention patent application with publication number CN111764821A discloses a microwave water jet synergistic rock-breaking method and device, which jointly breaks rocks through the microwave thermal effect and the auxiliary action of the water jet. However, this technology has the following essential limitations: 1) The water jet only serves as an auxiliary cooling medium, and the pressure range is limited, without exerting the impact fracturing ability of an ultra-high-pressure jet (100 - 250 MPa); 2) The influence of mineral component differences on energy coupling is not considered.

[0006] In addition, although microwave rock-breaking technology can deteriorate rocks, it has defects such as uneven heating and low energy utilization rate. Therefore, there is an urgent need for an efficient rock-breaking solution that can dynamically couple thermal energy and mechanical energy and adaptively adjust parameters. Summary of the Invention

[0007] Aiming at the technical problems of low energy coupling efficiency, poor parameter adaptability, and inaccurate timing control in the existing traditional hard rock crushing technology, the present invention provides a jet hard rock crushing device based on dynamic thermal-mechanical coupling, which realizes the efficient and low-energy consumption crushing of hard rock through the synergistic action of three stages: microwave pre-damage, jet impact, and vaporization expansion.

[0008] To solve the above technical problems, the present invention adopts the following technical solutions:

[0009] A jet hard rock crushing device based on dynamic thermal-mechanical coupling, comprising a microwave-jet coaxial module, a rock feature acquisition module, a multi-mode jet generation module, and an adaptive controller. The microwave-jet coaxial module is used to perform high-power microwave radiation and high-intensity jet impact on the rock to be crushed carried in the rock feature acquisition module, and ensure that the spatial regions of microwave radiation and jet impact are basically coincident. The rock feature acquisition module is used to collect in real time the temperature field and quartz content data of the rock to be crushed under microwave radiation targeted heating, so as to provide a jet trigger signal and a jet mode selection correspondingly. The multi-mode jet generation module is connected to the microwave-jet coaxial module and is used to provide two independent high-pressure jet modes, namely the abrasive jet mode and the pure water jet mode, to realize the adaptive crushing of the rock to be crushed. The adaptive controller is electrically connected to the microwave-jet coaxial module, the rock feature acquisition module, and the multi-mode jet generation module respectively, and is used to regulate the dynamic timing matching in the jet rock breaking process. Specifically, when the adaptive controller receives the jet trigger signal input by the rock feature acquisition module, it starts the multi-mode jet generation module within a preset time window, and adaptively selects the abrasive jet mode or the pure water jet mode according to the quartz content data input by the rock feature acquisition module to apply a cold and hot cycle jet impact to the surface of the rock to be crushed, and controls the microwave-jet coaxial module to synchronously apply intermittent microwave irradiation during the jet impact, so that the water injected into the rock cracks by the jet impact is heated and vaporized to increase the pressure, driving the autonomous expansion of the internal cracks of the rock.

[0010] Further, the microwave-jet coaxial module includes a microwave generator, a multi-channel jet nozzle is penetrated through the microwave generator, a circulator and a microwave converter are sleeved on the multi-channel jet nozzle extending out of the microwave generator, the waveguide outlet of the microwave generator and the multi-channel jet nozzle are in a concentric circle nested structure, and the microwave generator is electrically connected to the adaptive controller.

[0011] Further, the multi-channel jet nozzle includes a waveguide tube wall. Inside the waveguide tube wall, a central pure water jet channel and a peripheral abrasive jet annular cavity are coaxially arranged. The channel side wall of the central pure water jet channel is fixedly connected to the waveguide tube wall through a support frame. The support frame is locked to the waveguide tube wall through a limit bolt. A spiral guide groove is provided on the inner wall of the peripheral abrasive jet annular cavity. A mixing cavity is provided at the confluence of the outlet of the spiral guide groove and the central pure water jet channel and the peripheral abrasive jet annular cavity. The outlet of the mixing cavity serves as the jet outlet of the multi-channel jet nozzle and the feeding port of high-power microwave. A quartz lens is provided at the front end of the feeding port.

[0012] Further, two support bars are relatively fixedly arranged on the waveguide tube wall at the outlet side of the mixing cavity. An electric control slider is slidably arranged on the two support bars. The upper and lower ends of the quartz lens are fixedly connected to the two electric control sliders correspondingly.

[0013] Further, the rock feature acquisition module includes a support frame. Inside the support frame, a specimen bearing table for bearing the rock to be broken is provided. A pressing block is arranged outside the specimen bearing table. The pressing block is connected to the inner wall of the support frame through a hydraulic pump. An infrared thermal imager for real-time acquisition of the rock temperature field and an X-ray fluorescence spectrometer for real-time acquisition of the quartz content of the rock are also provided on the inner wall of the support frame. A data acquisition memory connected to the infrared thermal imager and the X-ray fluorescence spectrometer is arranged on the outer wall of the support frame. The data acquisition memory is electrically connected to the adaptive controller.

[0014] Further, an acoustic emission sensor is also arranged inside the pressing block on the side close to the specimen bearing table of the rock feature acquisition module. The acoustic emission sensor is electrically connected to the data acquisition memory and is used for real-time acquisition of the acoustic signal of the crack propagation inside the rock.

[0015] Further, the multi-mode jet generation module includes an abrasive jet generation unit and a pure water jet generation unit. The abrasive jet generation unit includes a first high-pressure water pump and an abrasive tank. The outlet of the first high-pressure water pump is connected to the inlet of the abrasive tank. The outlet of the abrasive tank is connected to the inlet of the peripheral abrasive jet annular cavity of the multi-channel jet nozzle. The pure water jet generation unit consists of a second high-pressure water pump. The outlet of the second high-pressure water pump is connected to the inlet of the central pure water jet channel of the multi-channel jet nozzle. The control ends of the first high-pressure water pump and the second high-pressure water pump are electrically connected to the adaptive controller.

[0016] The present invention also provides a method for jet-breaking hard rock based on dynamic thermal-mechanical coupling. In this method, the aforementioned jet-breaking hard rock device based on dynamic thermal-mechanical coupling is adopted. The method includes the following steps:

[0017] S1. Microwave pre-damage stage: The microwave-jet coaxial module uses high-frequency microwave targeted irradiation to heat the mineral interface inside the rock to be broken. The rock feature acquisition module continuously collects the change of the surface temperature field of the rock to be broken. When the temperature field reaches the preset thermal damage threshold, a jet trigger signal is generated. At the same time, the adaptive controller outputs a microwave irradiation termination signal to the microwave-jet coaxial module to trigger the termination of microwave irradiation.

[0018] S2. Jet impact stage: After receiving the jet trigger signal, the adaptive controller starts the multi-mode jet generation module within a preset time window, and adaptively selects the abrasive jet mode or the pure water jet mode according to the quartz content data input by the rock feature acquisition module to apply a cold and hot cycle jet impact to the surface of the rock to be broken.

[0019] S3. Vaporization expansion stage: During the jet impact process, the adaptive controller controls the microwave-jet coaxial module to synchronously apply intermittent microwave irradiation, and the microwave radiation area basically coincides with the spatial area of the jet impact area. Through the jet impact and thermal stress to strengthen the thermal-mechanical coupling, the water injected into the rock cracks by the jet impact is heated and vaporized to increase the pressure, generating a vaporization pressure to drive the autonomous expansion of the internal cracks of the rock. And the microwave irradiation energy density in this step is 50% of that in the microwave pre-damage stage.

[0020] Further, in step S2, when the quartz content input by the rock feature acquisition module is ≥ 25%, the adaptive controller selects the abrasive jet mode, and the jet pressure of the abrasive jet mode is set to 150 - 200 MPa; when the quartz content input by the rock feature acquisition module is < 25%, the adaptive controller selects the pure water jet mode, and the jet pressure of the pure water jet mode is set to 100 - 150 MPa.

[0021] Further, in step S3, when the adaptive controller detects that the autonomous crack expansion speed decreases by 10%, the adaptive controller automatically triggers the jet pressure to increase by 15 - 25% based on the original pressure and the microwave duty cycle to increase by 20 - 40%.

[0022] Compared with the prior art, the jet rock-breaking device and method based on dynamic thermal-mechanical coupling provided by the present invention have the following beneficial effects:

[0023] 1. Thermal-mechanical dual deterioration and synergistic effect: In the microwave pre-damage stage, by exciting the polarization effect of the mineral interface, a non-uniform thermal stress field is constructed inside the rock to form a micro-crack network; the simultaneously applied high-pressure jet generates a cold and hot alternating effect at the moment of impact, and uses the expansion coefficient difference between hard minerals such as quartz and the matrix to induce interface peeling and intergranular crack propagation, realizing the cross-scale synergistic rock-breaking of thermal damage and mechanical impact.

[0024] 2. Self-driven expansion and reinforcement of fractures: The water that enters the rock under the action of jet impact vaporizes and increases pressure under the secondary microwave irradiation, forming a directional expansion pressure to drive the bifurcation and derivation of the main fracture, breaking through the limitation of the traditional single jet that only relies on external loads to push cracks, enabling the fracture expansion path to autonomously extend along the weak plane of the rock, and significantly improving the energy utilization rate.

[0025] 3. Advantages of dynamic adaptive control: Intelligent switching of jet modes based on mineral component characteristics (quartz content threshold response) and precise matching of microwave-jet time sequences (triggered by thermal damage threshold), which overcomes the problems of over-crushing or under-crushing caused by the single energy form and poor parameter adaptability in traditional methods.

[0026] 4. Advantages of operation stability: Using normal temperature water as the jet medium to avoid the phase change control problem of supercritical fluids. Combining with the thermal excitation characteristics of microwave-absorbing abrasives, while improving the energy coupling efficiency, it reduces the device complexity and maintenance cost, and is suitable for continuous operation under complex geological conditions. Brief Description of the Drawings

[0027] Figure 1 It is a schematic structural diagram of a jet rock-breaking device based on dynamic thermal-mechanical coupling provided by the present invention.

[0028] Figure 2 It is a schematic structural diagram of a microwave-jet coaxial module provided by the present invention.

[0029] Figure 3 It is a schematic structural diagram of a multi-channel jet nozzle provided by the present invention.

[0030] Figure 4 It is a schematic structural diagram of a rock feature acquisition module provided by the present invention.

[0031] Figure 5 It is a schematic flow diagram of a jet rock-breaking method based on dynamic thermal-mechanical coupling provided by the present invention.

[0032] In the figure, 1 is a microwave-jet coaxial module; 11 is a microwave generator; 12 is a multi-channel jet nozzle; 120 is a waveguide tube wall; 121 is a central pure water jet channel; 122 is a peripheral abrasive jet annular cavity; 123 is a support frame; 124 is a limit bolt; 125 is a spiral flow guide groove; 126 is a mixing cavity; 127 is a quartz lens; 128 is a support bar; 129 is an electric control slider; 13 is a circulator; 14 is a microwave converter; 2 is a rock feature acquisition module; 21 is a support frame; 22 is a specimen bearing table; 23 is a pressing block; 24 is a hydraulic pump; 25 is an infrared thermal imager; 26 is an X-ray fluorescence spectrometer; 27 is an acquisition data memory; 28 is an acoustic emission sensor; 3 is a multi-mode jet generation module; 31 is an abrasive jet generation unit; 311 is a first high-pressure water pump; 312 is an abrasive tank; 32 is a pure water jet generation unit; 321 is a second high-pressure water pump; 4 is an adaptive controller. Specific embodiments

[0033] In order to make the technical means, creative features, achieved purposes and functions of the present invention easy to understand, the present invention will be further described below with reference to specific drawings.

[0034] In the description of the present invention, it should be understood that the orientation or positional relationship indicated by the terms "longitudinal", "radial", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc. is based on the orientation or positional relationship shown in the drawings, and is only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be construed as a limitation to the present invention. In the description of the present invention, unless otherwise specified, the meaning of "a plurality of" is two or more.

[0035] In the description of the present invention, it should be noted that unless otherwise clearly defined and limited, the terms "installation", "connection" and "connection" should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection or an integral connection; it can be a mechanical connection or an electrical connection; it can be directly connected or indirectly connected through an intermediate medium, and it can be the communication inside two elements. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to specific situations.

[0036] Please refer to Figure 1As shown in the figure, the present invention provides a jet rock-breaking device based on dynamic thermal-mechanical coupling, which includes a microwave-jet coaxial module 1, a rock feature acquisition module 2, a multi-mode jet generation module 3, and an adaptive controller 4. The microwave-jet coaxial module 1 is used to perform high-power microwave radiation and high-intensity jet impact on the rock to be broken (target or specimen) carried in the rock feature acquisition module 2, and ensure that the spatial regions of microwave radiation and jet impact are basically coincident. The rock feature acquisition module 2 is used to collect in real time the temperature field and quartz content data of the rock to be broken under microwave radiation targeted heating, so as to provide a jet trigger signal and jet mode selection correspondingly. The multi-mode jet generation module 3 is connected to the microwave-jet coaxial module 1 and is used to provide two independent high-pressure jet modes, namely the abrasive jet mode and the pure water jet mode, to achieve adaptive breaking of the rock to be broken. The adaptive controller 4 is electrically connected to the microwave-jet coaxial module 1, the rock feature acquisition module 2, and the multi-mode jet generation module 3 (as shown by the dotted lines in the figure) respectively, and is used to regulate the dynamic timing matching in the jet rock-breaking process. Specifically, when the adaptive controller 4 receives the jet trigger signal input by the rock feature acquisition module 2, it starts the multi-mode jet generation module 3 within a preset time window, and adaptively selects the abrasive jet mode or the pure water jet mode according to the quartz content data input by the rock feature acquisition module 2 to apply a cold and hot cycle jet impact to the surface of the rock to be broken, and controls the microwave-jet coaxial module 1 to synchronously apply intermittent microwave irradiation (secondary irradiation) during the jet impact, so that the water injected into the rock cracks by the jet impact is heated and vaporized to increase the pressure, driving the autonomous expansion of the internal cracks in the rock. Among them, the adaptive controller 4 can be implemented by using an existing single-chip microcomputer or programmable logic controller (PLC controller), which will not be elaborated here.

[0037] As a specific embodiment, please refer to Figure 2 As shown in the figure, the microwave-jet coaxial module 1 includes a microwave generator 11. A multi-channel jet nozzle 12 is penetrated through the microwave generator 11. A circulator 13 and a microwave converter 14 are sleeved on the multi-channel jet nozzle 12 extending out of the microwave generator 11. The waveguide outlet of the microwave generator 11 and the multi-channel jet nozzle 12 are arranged in a concentric nested structure, that is, the waveguide outlet of the microwave generator 11 and the multi-channel jet nozzle 12 are arranged in a coaxial structure to ensure that the spatial regions of microwave radiation and jet impact are basically coincident and achieve higher breaking efficiency. And the microwave generator 11 is electrically connected to the adaptive controller 4 to dynamically adjust the microwave power. Among them, the microwave generator 11 is a direct generator of high-power microwave; the multi-channel jet nozzle 12 is a multi-mode jet outlet and a feed port of high-power microwave, and is a direct component for rock breaking; the high-power microwave forms a microwave form available for rock breaking through the circulator 13 and the microwave converter 14 and is transmitted to the microwave feed port.

[0038] As a specific embodiment, please refer to Figure 3 As shown, the multi-channel jet nozzle 12 includes a waveguide wall 120. Inside the waveguide wall 120, a central pure water jet channel 121 and a peripheral abrasive jet annular cavity 122 are coaxially arranged, thus forming a double-tube structure. The channel side wall of the central pure water jet channel 121 is fixedly connected to the waveguide wall 120 through a support frame 123. The support frame 123 is locked on the waveguide wall 120 through a limit bolt 124. A spiral flow guiding groove 125 is provided on the inner wall of the annular cavity of the peripheral abrasive jet annular cavity 122 to improve the uniformity of abrasive distribution. At the confluence of the outlet of the spiral flow guiding groove 125, the central pure water jet channel 121 and the peripheral abrasive jet annular cavity 122, a mixing cavity 126 is provided. Through the mixing cavity 126, the abrasive can be further uniformly mixed. The outlet of the mixing cavity 126 serves as the jet outlet of the multi-channel jet nozzle 11 and the feeding port of high-power microwave. A quartz lens 127 is provided at the front end of the feeding port.

[0039] As a preferred embodiment, please refer to Figure 3 As shown, two support bars 128 are relatively fixed on the waveguide wall 120 on the outlet side of the mixing cavity 126. An electrically controlled slider 129 is slidably arranged on the two support bars 128. The upper and lower ends of the quartz lens 127 are fixedly connected to the two electrically controlled sliders 129 respectively. The specific structure and working principle of the electrically controlled slider 129 are well known to those skilled in the art. Thus, the microwave focal length of the quartz lens 127 can be adjusted under the cooperation and drive of the electrically controlled slider 129.

[0040] As a specific embodiment, please refer to Figure 4 As shown, the rock feature acquisition module 2 includes a support frame 21. Inside the support frame 21, a specimen bearing table 22 for bearing the rock to be broken is provided. A pressing block 23 is arranged outside the specimen bearing table 22. The pressing block 23 is connected to the inner wall of the support frame 21 through a hydraulic pump 24. Thus, the pressing block 23 can apply confining pressure to the specimen (rock to be broken) under the drive of the hydraulic pump 24. An infrared thermal imager 25 for real-time acquisition of the rock temperature field (to provide a jet trigger signal) and an X-ray fluorescence spectrometer 26 for real-time acquisition of the quartz content of the rock (to realize jet mode switching) are also provided on the inner wall of the support frame 21. An acquisition data memory 27 electrically connected to the infrared thermal imager 25 and the X-ray fluorescence spectrometer 26 is provided on the outer wall of the support frame 21, so as to send the acquired rock temperature field and rock quartz content data to the existing acquisition data memory 27 for storage. The acquisition data memory 27 is electrically connected to the adaptive controller 4 for providing real-time data for the decision-making of the adaptive controller 4.

[0041] As a preferred embodiment, please refer to Figure 4As shown, the rock feature acquisition module 2 further includes an acoustic emission sensor 28 disposed inside a pressing block 23 near one side of the specimen bearing table 22. The acoustic emission sensor 28 is electrically connected to the acquisition data memory 28 and is used to collect in real time the acoustic signals of crack propagation inside the rock, so that when the adaptive controller 4 detects that the crack self-expansion speed drops by a preset threshold, it automatically triggers the jet pressure to increase based on the original pressure and the intermittent microwave duty cycle to increase.

[0042] As a specific embodiment, please refer to Figure 1 As shown, the multi-mode jet generation module 3 includes an abrasive jet generation unit 31 and a pure water jet generation unit 32. The abrasive jet generation unit 31 includes a first high-pressure water pump 311 and an abrasive tank 312 for mixing abrasives. The outlet of the first high-pressure water pump 311 is connected to the inlet of the abrasive tank 312. The outlet of the abrasive tank 312 is connected to the inlet of the peripheral abrasive jet ring cavity 122 of the multi-channel jet nozzle 12. The pure water jet generation unit 32 is composed of a second high-pressure water pump 321. The outlet of the second high-pressure water pump 321 is connected to the inlet of the central pure water jet channel 121 of the multi-channel jet nozzle 12. The control ends of the first high-pressure water pump 311 and the second high-pressure water pump 321 are electrically connected to the adaptive controller 4 to dynamically adjust the jet pressure and abrasive concentration parameters. In this embodiment, the multi-mode jet generation module 3 includes two sets of independent jet units, adapts the jet mode according to the requirements of the rock to be broken, and the multi-mode jets do not interfere with each other during operation and can work simultaneously if necessary.

[0043] Please refer to Figure 5 As shown, the present invention also provides a method for jet-breaking hard rock based on dynamic thermal-mechanical coupling. In this method, the aforementioned jet-breaking hard rock device based on dynamic thermal-mechanical coupling is adopted. The method includes the following steps:

[0044] S1. Microwave pre-damage stage: The microwave-jet coaxial module 1 uses high-frequency microwaves (such as a frequency of 2.45 GHz and a power of 4 - 10 kW) to target irradiate and heat the mineral interface inside the rock to be broken. The rock feature acquisition module 2 collects in real time the change of the surface temperature field of the rock to be broken. Specifically, the infrared thermal imager 25 in the rock feature acquisition module 2 is used to monitor in real time the change of the surface temperature field of the broken rock. When the temperature field reaches a preset thermal damage threshold (the temperature when thermal-induced cracks in the rock begin to develop, generally considered to be 400 °C for granite and 200 °C for shale), a jet trigger signal is generated. At the same time, the adaptive controller 4 outputs a microwave irradiation termination signal to the microwave-jet coaxial module 1 to trigger the termination of microwave irradiation. Specifically, the adaptive controller 4 outputs a microwave irradiation termination signal to the microwave generator 11 in the microwave-jet coaxial module 1 to trigger the termination of microwave irradiation, forming a microcrack network induced by the compressive stress generated by the expansion of wave-absorbing minerals such as quartz.

[0045] S2. Jet impingement stage: After receiving the jet trigger signal, the adaptive controller 4 activates the multi-mode jet generation module 3 within a preset time window, and adaptively selects an abrasive jet mode or a pure water jet mode to apply a cold and hot cycle jet impingement to the surface of the rock to be broken according to the quartz content input by the rock feature acquisition module 2 (specifically collected in real time by the X-ray fluorescence spectrometer 26 in the rock feature acquisition module 2). The jet pressure is dynamically adjusted according to the rock's Proctor hardness coefficient. Since the quartz content is closely related to the rock hardness, the quartz content is selected as the discrimination basis for jet mode selection.

[0046] S3. Vaporization and expansion stage: During the jet impingement process, the adaptive controller 4 controls the microwave-jet coaxial module 1 to synchronously apply intermittent microwave irradiation. Specifically, the adaptive controller 4 controls the microwave generator 11 in the microwave-jet coaxial module 1 to synchronously apply intermittent microwave irradiation (duty cycle is 50%, pulse frequency is 0.5 - 2 Hz), and the microwave radiation area is basically spatially coincident with the jet impingement area. Through jet impingement and thermal stress to strengthen the thermal-mechanical coupling, the water injected into the rock fissures by the jet impingement is heated and vaporized to increase pressure, generating vapor pressure to drive the autonomous expansion of internal cracks in the rock. And the microwave irradiation energy density in this step is 50% of that in the microwave pre-damage stage, thereby significantly reducing the microwave energy consumption while maintaining crack expansion. Specifically, when the rock has formed a certain fracture network in the pre-damage stage and is injected with water by the high-pressure jet, the cracks and water will significantly enhance the local absorption of microwave energy, making the high-frequency microwave act more on the medium in the fissures. At this time, reducing the microwave energy density to 50% of the original pre-damage stage can still generate sufficient local heating and vapor pressure for crack expansion. The lower microwave output not only avoids overheating of the surrounding rock mass, improves the thermal-mechanical coupling efficiency and reduces the ineffective energy consumption. In addition, the pulsed microwave irradiation with a 50% duty cycle and jet impingement act alternately, and the cooling effect brought by the jet can be used to reduce the temperature of the rock mass, prevent thermal saturation and strengthen the thermal-mechanical coupling.

[0047] As a specific embodiment, in the step S2, when the quartz content input by the rock feature acquisition module 2 ≥ 25%, the adaptive controller 4 automatically selects the abrasive jet mode. The jet pressure of the abrasive jet mode is set to be adjustable from 150 - 200 MPa, and the abrasive type can select wave-absorbing materials such as silicon carbide / aluminum oxide according to the broken rock, and the abrasive concentration is dynamically adjustable. The fissures are extended synergistically by abrasive impact and thermal stress. When the quartz content input by the rock feature acquisition module 2 < 25%, the adaptive controller 4 automatically selects the pure water jet mode. The jet pressure of the pure water jet mode is set to be adjustable from 100 - 150 MPa, and the thermal shock tensile stress generated by the contact of the cold jet (20 - 30 °C) with the high-temperature rock is used to extend the fissures synergistically.

[0048] As a specific embodiment, when the adaptive controller 4 detects that the self-expansion speed of the crack (specifically collected in real time by the acoustic emission sensor 28 in the rock feature acquisition module 2) drops by 10%, the adaptive controller 4 automatically triggers the jet pressure to increase by 15-25% based on the original pressure and the microwave duty cycle to increase by 20-40% to maintain efficient crushing.

[0049] Compared with the prior art, the jet rock-breaking device and method based on dynamic thermal-mechanical coupling provided by the present invention have the following beneficial effects:

[0050] 1. Synergistic effect of thermal and mechanical double degradation: In the microwave pre-damage stage, by exciting the mineral interface polarization effect, a non-uniform thermal stress field is constructed inside the rock to form a microcrack network; the simultaneously applied high-pressure jet generates a cold and hot alternating effect at the moment of impact, and uses the expansion coefficient difference between hard minerals such as quartz and the matrix to induce interface peeling and intergranular crack propagation, realizing cross-scale synergistic rock breaking of thermal damage and mechanical impact.

[0051] 2. Reinforcement of crack self-driven expansion: The water entering the rock under the action of jet impact vaporizes and pressurizes under the secondary irradiation of microwaves, forming a directional expansion pressure to drive the main crack to bifurcate and derive, breaking through the limitation of the traditional single jet that only relies on external loads to push the crack, so that the crack expansion path extends autonomously along the weak surface of the rock, significantly improving the energy utilization rate.

[0052] 3. Advantage of dynamic adaptive control: Intelligent switching of jet modes based on mineral component characteristics (quartz content threshold response) and precise matching of microwave-jet time sequences (triggered by thermal damage threshold) overcome the problems of over-crushing or under-crushing caused by the single energy form and poor parameter adaptability in traditional methods.

[0053] 4. Advantage of operation stability: Using normal temperature water as the jet medium to avoid the phase change control problem of supercritical fluids, combined with the thermal excitation characteristics of microwave-absorbing abrasives, while improving the energy coupling efficiency, reducing the device complexity and maintenance cost, and being suitable for continuous operation under complex geological conditions.

[0054] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and not to limit them. Although the present invention has been described in detail with reference to the preferred embodiments, those of ordinary skill in the art should understand that the technical solutions of the present invention can be modified or equivalently replaced without departing from the purpose and scope of the technical solutions of the present invention, and they should all be covered within the scope of the claims of the present invention.

Claims

1. A jet crushing hard rock device based on dynamic thermal-mechanical coupling, characterized in that: It comprises a microwave-jet coaxial module, a rock feature acquisition module, a multi-mode jet generation module and an adaptive controller. The microwave-jet coaxial module is used to perform high-power microwave radiation and high-intensity jet impact on the rock to be crushed carried in the rock feature acquisition module, and ensure the spatial overlap between the microwave radiation area and the jet impact area; the rock feature acquisition module is used to collect the temperature field and quartz content data of the rock to be crushed by targeted heating of microwave radiation in real time, so as to provide jet trigger signals and jet mode selection accordingly; the multi-mode jet generation module is connected to the microwave-jet coaxial module, and is used to provide two independent high-pressure jet modes, an abrasive jet mode and a pure water jet mode, so as to realize adaptive crushing of the rock to be crushed; the adaptive controller The adaptive controller is electrically connected to the microwave-jet coaxial module, the rock feature acquisition module and the multi-mode jet generation module respectively, and is used to regulate the dynamic timing matching in the jet rock breaking process. Specifically, when the adaptive controller receives the jet trigger signal input by the rock feature acquisition module, it starts the multi-mode jet generation module within a preset time window, and according to the quartz content data input by the rock feature acquisition module, it adaptively selects the abrasive jet mode or the pure water jet mode to apply hot and cold cycle jet impact to the surface of the rock to be broken, and during the jet impact process, the microwave-jet coaxial module is controlled to synchronously apply intermittent microwave radiation, so that the water injected into the rock cracks by the jet impact is heated, vaporized and pressurized, thereby driving the internal cracks of the rock to expand autonomously.

2. The jet crushing hard rock device based on dynamic thermal-mechanical coupling according to claim 1 is characterized in that: The microwave-jet coaxial module includes a microwave generator, a multi-channel jet nozzle is provided through the microwave generator, a circulator and a microwave converter are sleeved on the multi-channel jet nozzle extending from the microwave generator, a concentric circle nesting structure is formed between the waveguide outlet of the microwave generator and the multi-channel jet nozzle, and the microwave generator is electrically connected to an adaptive controller.

3. The jet crushing hard rock device based on dynamic thermal-mechanical coupling according to claim 2 is characterized in that: The multi-channel jet nozzle includes a waveguide wall, a central pure water jet channel and a peripheral abrasive jet annular cavity are coaxially arranged inside the waveguide wall, the channel side wall of the central pure water jet channel is fixedly connected to the waveguide wall through a support frame, and the support frame is locked on the waveguide wall through a limit bolt, a spiral guide groove is provided on the inner wall of the annular cavity of the peripheral abrasive jet annular cavity, a mixing cavity is provided at the outlet of the spiral guide groove and the confluence of the central pure water jet channel and the peripheral abrasive jet annular cavity, the outlet of the mixing cavity serves as the jet outlet of the multi-channel jet nozzle and the feed port of high-power microwave, and a quartz lens is provided at the front end of the feed port.

4. The jet crushing hard rock device based on dynamic thermal-mechanical coupling according to claim 3 is characterized in that: Two support bars are relatively fixed on the waveguide wall at the outlet side of the mixing chamber, and electric control sliders are slidably arranged on the two support bars. The upper and lower ends of the quartz lens are correspondingly fixedly connected to the two electric control sliders.

5. The jet crushing hard rock device based on dynamic thermal-mechanical coupling according to claim 1 is characterized in that: The rock feature acquisition module includes a support frame, a specimen carrying platform for carrying the rock to be crushed is provided inside the support frame, a pressure block is provided on the periphery of the specimen carrying platform, and the pressure block is connected to the inner wall of the support frame through a hydraulic pump. An infrared thermal imager for real-time acquisition of the rock temperature field and an X-ray fluorescence spectrometer for real-time acquisition of the quartz content of the rock are also provided on the inner wall of the support frame. A collection data storage device electrically connected to the infrared thermal imager and the X-ray fluorescence spectrometer is provided on the outer wall of the support frame, and the collection data storage device is electrically connected to the adaptive controller.

6. The jet crushing hard rock device based on dynamic thermal-mechanical coupling according to claim 5 is characterized in that: The rock feature acquisition module also includes an acoustic emission sensor disposed inside a pressing block on one side close to the specimen bearing platform. The acoustic emission sensor is electrically connected to an acquisition data storage device and is used to acquire real-time acoustic signals of crack propagation inside the rock.

7. The jet crushing hard rock device based on dynamic thermal-mechanical coupling according to claim 3 is characterized in that: The multi-mode jet generating module includes an abrasive jet generating unit and a pure water jet generating unit. The abrasive jet generating unit includes a first high-pressure water pump and an abrasive tank. The outlet of the first high-pressure water pump is connected to the inlet of the abrasive tank. The outlet of the abrasive tank is connected to the inlet of the peripheral abrasive jet ring cavity of the multi-channel jet nozzle. The pure water jet generating unit is composed of a second high-pressure water pump. The outlet of the second high-pressure water pump is connected to the inlet of the central pure water jet channel of the multi-channel jet nozzle. The control ends of the first high-pressure water pump and the second high-pressure water pump are electrically connected to the adaptive controller.

8. A method for jet crushing hard rock based on dynamic thermal-mechanical coupling, characterized in that: In this method, a jet crushing hard rock device based on dynamic thermal-mechanical coupling as described in any one of claims 1 to 7 is used, and the method comprises the following steps: S1, microwave pre-damage stage: the microwave-jet coaxial module uses high-frequency microwave targeted irradiation to heat the internal mineral interface of the rock to be broken, and the rock feature acquisition module collects the temperature field changes on the surface of the rock to be broken in real time. When the temperature field reaches a preset thermal damage threshold, a jet trigger signal is generated, and at the same time, the adaptive controller outputs a microwave irradiation termination signal to the microwave-jet coaxial module to trigger the termination of microwave irradiation; S2, jet impact stage: after receiving the jet trigger signal, the adaptive controller starts the multi-mode jet generation module within a preset time window, and adaptively selects the abrasive jet mode or the pure water jet mode to apply hot and cold cycle jet impact to the surface of the rock to be crushed according to the quartz content data input by the rock feature acquisition module; S3, vaporization expansion stage: during the jet impact process, the adaptive controller controls the microwave-jet coaxial module to synchronously apply intermittent microwave irradiation, and the microwave radiation area and the jet impact area overlap in space, and the jet impact and thermal stress strengthen the thermal-mechanical coupling, so that the water injected into the rock cracks by the jet impact is heated, vaporized and pressurized, generating vaporization pressure, driving the cracks inside the rock to expand autonomously, and the microwave irradiation energy density in this step is 50% of that in the microwave pre-damage stage.

9. The method for jet crushing hard rock based on dynamic thermal-mechanical coupling according to claim 8, characterized in that: In step S2, when the quartz content input by the rock feature acquisition module is ≥25%, the adaptive controller selects the abrasive jet mode, and the jet pressure of the abrasive jet mode is set to 150-200MPa; when the quartz content input by the rock feature acquisition module is <25%, the adaptive controller selects the pure water jet mode, and the jet pressure of the pure water jet mode is set to 100-150MPa.

10. The method for jet crushing hard rock based on dynamic thermal-mechanical coupling according to claim 8, characterized in that: In step S3, when the adaptive controller detects that the crack autonomous propagation speed decreases by 10%, the adaptive controller automatically triggers the jet pressure to increase by 15-25% based on the original pressure and the microwave duty cycle to increase by 20-40%.

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