Rockburst prevention and control device for insensitive hard rock based on combination of hydraulic power and microwaves

Abstract

The invention belongs to the field of tunnel construction and the field of deep engineering disaster prevention and control, and provides a hydraulic and microwave combined insensitive hard rock burst prevention and control device which comprises a vehicle-mounted system, a hydraulic fracturing system and a microwave emission system. The hydraulic fracturing system is used for injecting water into the insensitive hard rock drill hole, forming a hydraulic fracturing crack on the circumferential wall surface of the insensitive hard rock drill hole, and then injecting a sensitive mineral proppant to fill the hydraulic fracturing crack; the microwave emission system is used for moving into the insensitive hard rock drill hole for microwave irradiation after the sensitive mineral proppant is injected; according to the method, hydraulic fracturing, microwave fracturing and sensitive mineral filling are combined and applied to fracturing and pressure relief of the insensitive hard rock of the deep tunnel, and due to the fact that sensitive minerals have high dielectric constants and dielectric loss factors, a good temperature rise effect can be shown under microwave irradiation.

Description

Technical Field

[0001] The present invention belongs to the fields of tunnel construction and deep engineering disaster prevention and control, and particularly relates to a rock burst prevention and control device for insensitive hard rock based on the combination of hydraulic power and microwave. Background Technique

[0002] Traditional drilling and blasting methods and mechanical methods often show problems such as high excavation energy consumption, large pollution, and low efficiency in deep hard rock excavation. Therefore, many scholars have suggested pre-treating the rock mass surface or in-hole with microwave irradiation before deep hard rock excavation, so as to effectively reduce the wear of drilling tools and energy consumption during excavation. However, since insensitive hard rocks such as granite are mainly composed of insensitive minerals such as quartz, alkali feldspar, plagioclase, and calcite (sensitive minerals refer to minerals with a relatively large dielectric constant and dielectric loss factor Minerals with larger values are microwave-sensitive minerals, and the microwave sensitivity of ore minerals (such as chalcopyrite, magnetite) is generally much greater than that of gangue minerals (such as quartz, plagioclase)), and their absorption capacity for microwaves is poor, and the heating effect is not obvious, resulting in a poor weakening effect on their strength after microwave action. Therefore, the current research ignores the specific analysis of the microwave sensitivity of deep hard rock, and there is an urgent need for new hard rock microwave cracking and pressure relief equipment and methods to solve the problems of small cracking and pressure relief range and poor effect of deep insensitive hard rock.

[0003] With the continuous increase in the depth of underground engineering construction, there are a large number of high-intensity earthquakes, high ground stress, high ground temperature, and strongly developed diverse geological disasters in deep hard rock mining, which seriously restricts the efficient construction and safe operation of deep hard rock tunnels. In particular, strong tectonic activities and drastic topographic changes have led to a complex stress field environment, which brings geological safety risks to the construction and even the entire life cycle operation of deep-buried hard rock tunnels. Among them, more serious are engineering disasters such as tunnel rock bursts and strong brittle failures caused by high ground stress. Therefore, there is an urgent need for a safe and efficient deep hard rock cracking and pressure relief technology to reduce the occurrence risk of rock bursts in hard rock tunnels and achieve safe, economic, and efficient deep underground engineering construction.

[0004] Hydraulic fracturing and microwave fracturing are two highly potential hard rock fracturing and pressure relief methods, both of which have the advantages of pollution-free and easy operation. Among them, hydraulic fracturing means pumping high-pressure liquid into the sealed section of the surrounding rock borehole to fracture the rock, forming multiple fractures or fracture networks, and then maintaining the fracture opening state and further increasing the number and aperture of fractures by increasing the pumping pressure and adding proppant-containing plugging fluid, so as to achieve the pressure relief of high-stress rock mass. Microwave fracturing is to connect the anode high-voltage power supply and the filament power supply through a cable. After the filament is preheated, the anode high-voltage power supply is turned on. When a high voltage is generated at the anode and applied to the cathode, a large number of electrons are heated and ejected. When the electrons move to the anode, they will repel the electrons close to them in space. These electrons move to the surface of the nearby cavity metal, forming a negatively charged surface, while the cavity surface from which the electrons are repelled will be positively charged due to the lack of electrons. When such charges are induced in all cavities, these distributed charges will oscillate and finally generate microwave emission. Due to the selective heating characteristics of microwaves, the hard rock around the borehole is non-uniformly heated, and the temperature rise characteristics of different minerals are different. For example, the heating rate of the microwave-sensitive mineral biotite is much higher than that of the microwave-insensitive mineral quartz. Therefore, a large temperature gradient will be generated at the mineral grain boundaries, and then thermal stress will be formed. Coupled with the interaction force generated by the thermal expansion of the minerals, the two work together to cause the hard rock to crack. However, when using hydraulic fracturing or microwave fracturing alone to weaken and relieve the pressure of insensitive hard rock, problems such as high energy consumption (electrical energy, water resources), small weakening range, and poor weakening effect often occur. Therefore, the advantages of the two can be utilized and organically combined to break through the technical bottleneck, achieve high-energy and high-efficiency fracturing and pressure relief of deep insensitive hard rock tunnels, and thus prevent rock bursts from occurring. Summary of the Invention

[0005] To solve the above technical problems, the present invention provides a rock burst prevention and control device for insensitive hard rock based on the combination of hydraulics and microwaves to solve the problems in the prior art. The technical solution adopted by the present invention is as follows: A rock burst prevention and control device for insensitive hard rock based on the combination of hydraulics and microwaves, comprising a vehicle-mounted system, a hydraulic fracturing system, and a microwave emission system; The hydraulic fracturing system and the microwave emission system are respectively installed on the vehicle-mounted system through a mobile platform; The hydraulic fracturing system is used to first inject water into the borehole of insensitive hard rock and form hydraulic fracturing cracks on the circumferential wall surface of the borehole of insensitive hard rock, and then inject sensitive mineral proppants to fill the hydraulic fracturing cracks; The microwave emission system is used to move into the borehole of insensitive hard rock after the injection of sensitive mineral proppants, and irradiate the inner wall surface of the borehole of insensitive hard rock with microwaves, so as to increase the temperature of the hydraulic fracturing cracks through the sensitive mineral proppants, form a temperature difference in the borehole of insensitive hard rock, and improve the hard rock fracturing performance.

[0006] Further, the microwave emission system includes a box body, a high-frequency power supply, a 15kW microwave head, a water load device, a rectangular waveguide, a rectangular-circular conversion device, a coaxial transmission waveguide, and a coaxial microwave radiator; The box body is installed on the mobile platform, the high-frequency power supply is installed inside the box body, the 15kW microwave head is installed on the top of the box body, and the output end of the 15kW microwave head is sequentially connected to the water load device, the rectangular waveguide, the rectangular-circular conversion device, the coaxial transmission waveguide, and the coaxial microwave radiator; The coaxial microwave radiator is adapted to an insensitive hard rock drill hole and is used to be inserted into the insensitive hard rock drill hole and emit microwaves.

[0007] Further, a manual three-pin tuner is provided on the rectangular waveguide to change the inductance value and tune the circuit; a microwave power meter is provided on the rectangular waveguide to monitor the input and output power of the microwave in real time.

[0008] Further, the hydraulic fracturing system includes a first pipeline, a second pipeline, a hole packer, and a high-pressure hydraulic fracturing pump; The first pipeline and the second pipeline are arranged side by side. One end of the two pipelines is used to be inserted into the insensitive hard rock drill hole, and the other end is connected to the output end of the high-pressure hydraulic fracturing pump through a three-way valve; A first pipeline through hole is opened on the side surface of one end of the first pipeline inserted into the insensitive hard rock drill hole; two hole packers are provided at one end of the second pipeline inserted into the insensitive hard rock drill hole, and the fracturing section of the insensitive hard rock drill hole is between the two hole packers; the first pipeline through hole is located in the fracturing section; The second pipeline is used to inject water into the two hole packers through the high-pressure hydraulic fracturing pump to seal the fracturing section by the two hole packers; The first pipeline is used to first inject water into the fracturing section through the high-pressure hydraulic fracturing pump to form hydraulic fracturing cracks on the circumferential wall surface of the fracturing section, and then inject sensitive mineral proppants to fill the hydraulic fracturing cracks.

[0009] Further, the hydraulic fracturing system further includes a cabinet, a water storage tank, and a plugging liquid tank; The cabinet is installed on the mobile platform, the water storage tank and the plugging liquid tank are installed inside the cabinet, the water storage tank is connected to one input end of the high-pressure hydraulic fracturing pump through a first valve and a pipeline, and the plugging liquid tank is connected to the other input end of the high-pressure hydraulic fracturing pump through a second valve and a pipeline; A proppant filling port is provided on the first pipeline for adding sensitive mineral proppants into the first pipeline; When sealing the fracturing section, open the first valve, close the second valve, and rotate the three-way valve to connect the hydraulic fracturing high-pressure pump to the second pipeline and the water storage tank, and the hydraulic fracturing high-pressure pump injects water into the second pipeline; When performing hydraulic fracturing, open the first valve, close the second valve, and rotate the three-way valve to connect the hydraulic fracturing high-pressure pump to the first pipeline and the water storage tank, and the hydraulic fracturing high-pressure pump injects water into the first pipeline; When filling with sensitive mineral proppants, open the second valve and close the first valve. The hydraulic fracturing high-pressure pump is connected to the first pipeline and the plugging liquid tank. Sensitive mineral proppants are added through the proppant filler opening, and the sensitive mineral proppants mixed with the plugging liquid are injected into the fracturing section to fill the hydraulic fracturing cracks.

[0010] Furthermore, the output end of the hydraulic fracturing high-pressure pump is connected to an output pipe, and the output pipe is connected to the first pipeline and the second pipeline through the three-way valve; a pressure relief valve is provided on the output pipe to output the medium in the insensitive hard rock borehole.

[0011] Furthermore, the hole sealer includes an annular elastic seal and two sealing plates. The two sealing plates are fixedly connected to the second pipeline, and the annular elastic seal is fixedly connected between the two sealing plates; The annular elastic seal is annular, and it and the two sealing plates together form an elastic chamber. A second pipeline through-hole is provided on the side of the second pipeline located inside the elastic chamber; The second pipeline injects water into the elastic chamber through the second pipeline through-hole, so that the annular elastic seal expands outwards to abut against the inner wall surface of the insensitive hard rock borehole to form a seal.

[0012] Furthermore, a blocking mechanism is provided between the first pipeline and the second pipeline. The blocking mechanism is located outside the fracturing section and is between the fracturing section and the hydraulic fracturing high-pressure pump; The blocking mechanism includes a first piston, a connecting rod, a second piston, a spring, a connecting pipe and a side pipe; the side pipe is fixedly connected to the side of the second pipeline. The opposite ends of the first piston and the second piston are fixedly connected to the connecting rod. The sides of the first pipeline and the second pipeline are connected through the connecting pipe; the first piston and the second piston are adapted to the connecting pipe. The first piston is slidably located in the connecting pipe, the second piston is slidably located in the side pipe, and the spring abutting against the second piston is provided in the side pipe; When the medium is injected into the first pipeline, the first piston is pushed to move under the internal pressure, so that the first piston crosses and blocks the second pipeline. The diameter of the connecting rod is smaller than that of the first piston and the second piston.

[0013] The present invention has the following beneficial effects: The present invention combines hydraulic fracturing, microwave-induced fracturing, and filling of sensitive minerals and applies them to the fracturing and pressure relief of insensitive hard rock in deep-buried tunnels. Through hydraulic fracturing, preliminary fracturing in the borehole of insensitive hard rock and filling of sensitive mineral proppants in the fractures are achieved. Since sensitive minerals have a high dielectric constant and dielectric loss factor, they can exhibit good temperature rise effects under microwave irradiation; the microwave emission system heats and damages the hard rock mass in the tunnel, and the sensitive mineral proppants rapidly heat up to generate a large temperature gradient and high thermal stress with the surrounding insensitive hard rock, which helps the further expansion, development, and penetration of existing fractures, significantly reducing the strength of insensitive hard rock. The result of the combined action is to increase the fracturing range of insensitive hard rock, improve the fracturing and pressure relief effect of hard rock, and be able to more effectively prevent and control rockburst disasters. Brief Description of the Drawings

[0014] Figure 1 is a schematic diagram of the overall structure of the present invention; Figure 2 is a schematic diagram during hydraulic fracturing; Figure 3 is a schematic diagram during the filling of sensitive mineral proppants; Figure 4 is a schematic diagram after microwave heating and fracturing; Figure 5 is a schematic diagram of the structure of the plugging device 5; Figure 6 is a schematic diagram when the blocking mechanism blocks the second pipeline; In the figure: fracturing section 1, first pipeline through-hole 2, second pipeline through-hole 3, rubber sealing ring 4, plugging device 5, crack after hydraulic fracturing 6, first pipeline 7, second pipeline 8, three-way valve 9, pressure relief valve 10, proppant filling port 11, liquid injection control system 12, hydraulic fracturing measurement and control instrument 13, hydraulic fracturing high-pressure pump 14, water storage tank 15, first valve 16, plugging liquid tank 17, second valve 18, mounting plate 19, water cooling box 20, high-frequency power supply 21, 15kW microwave head 22, water load device 23, microwave power meter 24, manual three-pin adjuster 25, rectangular waveguide 26, rectangular-circular conversion device 27, coaxial transmission waveguide 28, ceramic fiber membrane 29, thermal insulation and heat insulation nano material layer 30, coaxial microwave radiator 31, crack after microwave fracturing 32, mobile platform 33, surrounding rock 34, vehicle-mounted system 35, microwave emission system 36, hydraulic fracturing system 37, crack after proppant plugging 38, mixed proppant plugging liquid 39, 10-20 mesh proppant 40, 20-40 mesh proppant 41, 40-60 mesh proppant 42, sealing plate 501, annular elastic seal 502, blocking mechanism 801, first piston 8011, connecting rod 8012, second piston 8013, spring 8014, connecting pipe 8015, side pipe 8016. Detailed implementation mode

[0015] The following will combine the Figures 1 - 6 in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. If not specifically specified, the technical means used in the embodiments are conventional means well-known to those skilled in the art.

[0016] Such as Figure 1 , a rockburst prevention and control device for insensitive hard rock based on the combination of hydraulic power and microwave, including a vehicle-mounted system 35, a hydraulic fracturing system 37 and a microwave emission system 36; The hydraulic fracturing system 37 and the microwave emission system 36 are respectively installed on the vehicle-mounted system 35 through a mobile platform 33; The hydraulic fracturing system 37 is used to first inject water into the borehole of insensitive hard rock and form hydraulic fracturing cracks 6 on the circumferential wall surface of the borehole of insensitive hard rock, and then inject sensitive mineral proppants to fill the hydraulic fracturing cracks 6; The microwave emission system 36 is used to move into the borehole of insensitive hard rock after the injection of sensitive mineral proppants, and irradiate the inner wall surface of the borehole of insensitive hard rock with microwaves, so that the hydraulic fracturing cracks 6 are heated by the sensitive mineral proppants, forming a temperature difference in the borehole of insensitive hard rock and improving the fracturing performance of hard rock.

[0017] The vehicle-mounted system 35 and the mobile platform 33 are prior arts. The vehicle-mounted system 35 can be a modified truck, and the mobile platform 33 is installed at the rear of the vehicle-mounted system 35. The mobile platform 33 can be an up-and-down mobile platform composed of jacks or a three-axis mobile platform, and its purpose is to move the hydraulic fracturing system 37 and the microwave emission system 36 so that the two are inserted into the corresponding boreholes of insensitive hard rock. The boreholes of insensitive hard rock on the surrounding rock 34 are pre-drilled by a drill. There is no additional power supply device on the vehicle-mounted system 35, and the required 380V alternating current is provided by the tunnel circuit. The on-site power supply is connected to the microwave emission system 36 and the hydraulic fracturing system 37.

[0018] The present invention combines hydraulic fracturing, microwave and sensitive mineral proppants for the fracturing and pressure relief of insensitive hard rock in deep tunnels. The hydraulic fracturing system 37 is used for the preliminary fracturing of insensitive hard rock and creating a filling space for sensitive mineral proppants; the microwave emission system 36 emits microwaves to heat and weaken the hard rock around the hole, resulting in cracks in the rock mass, greatly reducing the stress level of the rock mass; through the sensitive mineral proppants, the fissure area of insensitive hard rock is rapidly heated, increasing the temperature gradient between the high-temperature area of hard rock and the surrounding insensitive hard rock, stimulating higher thermal stress between hard rock masses, and improving the fracturing and pressure relief range and effect of the surrounding rock mass.

[0019] The microwave emission system 36 of the present invention specifically includes a high-frequency power supply 21, a 15kW microwave head 22, a water load device 23, a rectangular waveguide 26, a rectangular-circular conversion device 27, a coaxial transmission waveguide 28, a coaxial microwave radiator 31, and a mounting plate 19; The box body is installed on the mobile platform 33. The high-frequency power supply 21 is installed inside the box body. The 15kW microwave head 22 is installed on the top of the box body. The output end of the 15kW microwave head 22 is sequentially connected to the water load device 23, the rectangular waveguide 26, the rectangular-circular conversion device 27, the coaxial transmission waveguide 28, and the coaxial microwave radiator 31; The coaxial microwave radiator 31 is adapted to an insensitive hard rock drill hole and is used to be inserted into the insensitive hard rock drill hole and emit microwaves.

[0020] The high-frequency power supply 21, the 15kW microwave head 22, the water load device 23, the rectangular waveguide 26, the rectangular-circular conversion device 27, the coaxial transmission waveguide 28, and the coaxial microwave radiator 31 are all prior arts. The water load device 23 is connected to the water cooling box 20 to improve the water circulation cooling to protect the microwave head. The coaxial microwave radiator 31 has a diameter of 80mm and a length of 500mm, and the side opening has a diameter of 20mm. The opening is used to expose microwaves to the insensitive hard rock around the drill hole.

[0021] In addition, a manual three-pin tuner 25 is provided on the rectangular waveguide 26 to change the inductance value to tune the circuit; a microwave power meter 24 is provided on the rectangular waveguide 26 to real-time monitor the input and output power of the microwave. The manual three-pin tuner 25 and the microwave power meter 24 are both prior arts. The bottom of the box body can be fixedly installed on the mobile platform 33 through the mounting plate 19.

[0022] The hydraulic fracturing system 37 of the present invention includes a first pipeline 7, a second pipeline 8, a hole packer 5, and a hydraulic fracturing high-pressure pump 14; The first pipeline 7 and the second pipeline 8 are arranged side by side. One end of them is used to be inserted into the insensitive hard rock drill hole, and the other end is connected to the output end of the hydraulic fracturing high-pressure pump 14 through a three-way valve 9; A first pipeline through hole 2 is opened on the side of the end of the first pipeline 7 inserted into the insensitive hard rock drill hole; two hole packers 5 are provided at the end of the second pipeline 8 inserted into the insensitive hard rock drill hole. The fracturing section 1 of the insensitive hard rock drill hole is between the two hole packers 5; the first pipeline through hole 2 is located in the fracturing section 1; The second pipeline 8 is used to inject water into the two hole packers 5 through the hydraulic fracturing high-pressure pump 14 to make the two hole packers 5 seal the fracturing section 1; The first pipeline 7 is used to first inject water into the fracturing section 1 through the hydraulic fracturing high-pressure pump 14 to form hydraulic fracturing cracks 6 on the circumferential wall surface of the fracturing section 1, and then inject sensitive mineral proppants to fill the hydraulic fracturing cracks 6.

[0023] Specifically, the hydraulic fracturing high-pressure pump 14 is a prior art, and it is connected to a liquid injection control system 12 for controlling pressure. The first pipeline 7 and the second pipeline 8 can be connected by components such as pipe clamps. The hydraulic fracturing high-pressure pump 14 injects high-pressure water into the first pipeline 7, thereby forming hydraulic fracturing cracks 6 in the fracturing section 1, forming Figure 2 a state. After the hydraulic fracturing cracks 6 are formed, the water body is discharged and sensitive mineral proppants are injected into the hydraulic fracturing cracks 6 through the first pipeline 7.

[0024] The sensitive mineral proppants of the present invention can be chalcopyrite or magnetite particles, and are divided into 10-20 mesh proppants 40, 20-40 mesh proppants 41, and 40-60 mesh proppants 42 according to particle size; in specific implementation, the sensitive mineral proppants are incorporated in ascending order, forming Figure 3 a state, thereby ensuring that the hydraulic fracturing cracks 6 are fully filled with sensitive mineral proppants, and at the same time ensuring that the small-particle-size mineral proppants in the upper part will not slide off from the cracks due to gravity after pressure relief. Such sensitive ore mineral proppants have a high dielectric constant and dielectric loss factor, and have an excellent heating effect under microwave irradiation.

[0025] Furthermore, the hydraulic fracturing system 37 further includes a cabinet, a water storage tank 15, and a plugging liquid tank 17; The cabinet is installed on the mobile platform 33, the water storage tank 15 and the plugging liquid tank 17 are installed in the cabinet, the water storage tank 15 is connected to one input end of the hydraulic fracturing high-pressure pump 14 through a first valve 16 and a pipeline, and the plugging liquid tank 17 is connected to the other input end of the hydraulic fracturing high-pressure pump 14 through a second valve 18 and a pipeline; A proppant filling port 11 is provided on the first pipeline 7 for adding sensitive mineral proppants into the first pipeline 7; The working stages of the hydraulic fracturing system 37 of the present invention are as follows: When sealing the fracturing section 1, open the first valve 16, close the second valve 18, and rotate the three-way valve 9 to connect the hydraulic fracturing high-pressure pump 14 to the second pipeline 8 and the water storage tank 15, and the hydraulic fracturing high-pressure pump 14 injects water into the second pipeline 8; the purpose of this stage is to seal the fracturing section 1 through the packer 5.

[0026] During hydraulic fracturing, the first valve 16 is opened, the second valve 18 is closed, and the three-way valve 9 is rotated to connect the high-pressure hydraulic fracturing pump 14 to the first pipeline 7 and the water storage tank 15, and the high-pressure hydraulic fracturing pump 14 injects water into the first pipeline 7; the purpose of this stage is to form a hydraulic fracturing crack 6 by injecting high-pressure water from the through-hole 2 of the first pipeline.

[0027] When filling with sensitive mineral proppant, the second valve 18 is opened, the first valve 16 is closed, the high-pressure hydraulic fracturing pump 14 is connected to the first pipeline 7 and the plugging liquid tank 17, and sensitive mineral proppant is added through the proppant filling port 11, so that the sensitive mineral proppant mixed with the plugging liquid is injected into the fracturing section 1 and fills the hydraulic fracturing crack 6. The purpose of this stage is to fill the fracturing section 1 with a mixed medium of sensitive mineral proppant and plugging liquid, and plug the hydraulic fracturing crack 6. After plugging, the hydraulic fracturing crack 6 forms a proppant-plugged crack 38.

[0028] In addition, the hydraulic fracturing system 37 can be moved by the vehicle-mounted system 35 and the mobile platform 33, so as to work in different boreholes, and can work sequentially in the fracturing sections 1 at different depth positions in the borehole.

[0029] After filling with sensitive mineral proppant and plugging liquid, a heat-insulating nano material layer 30 can be laid in the insensitive hard rock borehole, and then fractured by irradiation with the microwave emission system 36. The heat-insulating nano material layer 30 can be prefabricated into a coil and then laid manually, or can be formed in the hole by spraying, forming Figure 4 the state in

[0030] The main materials of the heat-insulating nano material layer 30 are silica and alkali-free glass fiber. On the one hand, it can play a heat-insulating role for the hard rock after microwave heating, preventing heat consumption caused by the convection of the rock mass and the air; on the other hand, it can prevent the broken rock blocks and high-temperature molten substances after microwave irradiation from damaging the coaxial microwave radiator 31. At the same time, both silica and glass micro are microwave-transparent materials, and microwaves can penetrate without loss, so the microwave-induced fracturing efficiency of hard rock will not be reduced.

[0031] Furthermore, the output end of the high-pressure hydraulic fracturing pump 14 is connected to an output pipe, and the output pipe is connected to the first pipeline 7 and the second pipeline 8 through the three-way valve 9; a pressure relief valve 10 is arranged on the output pipe to output the medium in the insensitive hard rock borehole.

[0032] The pressure relief valve 10 is used to relieve the pressure of the liquid flowing out of the fracturing section 1 or the packer 5. For example, after filling the sensitive mineral proppant in a certain fracturing section 1, when moving to the next section or the next borehole to continue hydraulic fracturing, first rotate the three-way valve 9 and the pressure relief valve 10 in sequence to release the residual plugging liquid in the fracturing section 1, and then rotate the three-way valve 9 and the pressure relief valve 10 in sequence to release the water in the packer 5. The packer 5 shrinks, and the hydraulic fracturing measurement and control instrument 13 monitors that the pressure is zero. Then, move to the next section for hydraulic fracturing through the mobile platform 33, or move to the next borehole for hydraulic fracturing through the vehicle-mounted system 35. The hydraulic fracturing measurement and control instrument 13 is used to monitor the water pressure in real time, and then judge the progress of the hydraulic fracturing operation. For example, during hydraulic fracturing, after the pressure peak drops suddenly, continue to inject water for fracturing to ensure that the fracture expands fully. When the water pressure monitored by the hydraulic fracturing measurement and control instrument 13 is less than 5 MPa, adjust the pressure regulating knob slowly to the zero position, and turn off the switch of the hydraulic fracturing high-pressure pump 14, and the hydraulic fracturing stage ends. Another example is that during the filling of sensitive mineral proppants, if the pump injection pressure rises by 3 - 5 MPa, it indicates that the plugging effect is good. If the effect is not good, then use a higher material-water mass ratio.

[0033] Such as Figure 5 、 Figure 6 The packer 5 includes an annular elastic seal 502 and two sealing plates 501. The two sealing plates 501 are fixedly connected to the second pipe 8, and the annular elastic seal 502 is fixedly connected between the two sealing plates 501; The annular elastic seal 502 is annular, and it forms an elastic chamber together with the two sealing plates 501. A second pipe through hole 3 is opened on the side of the second pipe 8 located in the elastic chamber; The second pipe 8 injects water into the elastic chamber through the second pipe through hole 3, so that the annular elastic seal 502 expands outwards to abut against the inner wall surface of the insensitive hard rock borehole to form a seal.

[0034] The sealing plate 501 is in a disc structure and is adapted to the insensitive hard rock borehole. Rubber sealing rings 4 are also provided at the opposite ends of the two sealing plates 501. The annular elastic seal 502 can be a rubber bellows, which has sufficient elasticity and expands by water pressure to abut against the inner wall surface of the insensitive hard rock borehole to form an effective seal. The two packers 5 can be divided into an inner packer 5 and an outer packer 5 according to their positions in the hole. The first pipe 7 and the second pipe 8 pass through the two sealing plates 501 of the outer packer 5 and are sealed and connected. The second pipe 8 passes through the outer sealing plate 501 of the inner packer 5 and is fixedly connected to the inner sealing plate 501.

[0035] Further, a blocking mechanism 801 is provided between the first pipeline 7 and the second pipeline 8. The blocking mechanism 801 is located outside the fracturing section 1 and is between the fracturing section 1 and the high-pressure hydraulic fracturing pump 14. The blocking mechanism 801 includes a first piston 8011, a connecting rod 8012, a second piston 8013, a spring 8014, a connecting pipe 8015 and a side pipe 8016. The side pipe 8016 is fixedly connected to the side of the second pipeline 8. One end of the first piston 8011 opposite to the second piston 8013 is fixedly connected to the connecting rod 8012. The sides of the first pipeline 7 and the second pipeline 8 are communicated through the connecting pipe 8015. The first piston 8011 and the second piston 8013 are adapted to the connecting pipe 8015. The first piston 8011 is slidably located in the connecting pipe 8015, and the second piston 8013 is slidably located in the side pipe 8016. The spring 8014 that abuts against the second piston 8013 is arranged in the side pipe 8016. When a medium is injected into the first pipeline 7, the first piston 8011 is pushed to move under the action of the internal pressure, so that the first piston 8011 crosses and blocks the second pipeline 8. The diameter of the connecting rod 8012 is smaller than that of the first piston 8011 and the second piston 8013.

[0036] During hydraulic fracturing and filling of sensitive mineral proppants, it is necessary to maintain the expanded state of the packer 5. Therefore, it is necessary to block the second pipeline 8. The blocking of the second pipeline 8 is jointly realized by the blocking mechanism 801 and the three-way valve 9.

[0037] Specifically, as Figure 6 , when there is high-pressure water or sensitive mineral proppants in the first pipeline 7, due to the action of the internal pressure of the first pipeline 7, the first piston 8011 is pushed to move, so that the first piston 8011 crosses and blocks the first pipeline 7. When the first pipeline 7 is emptied, the spring 8014 pushes the second piston 8013 to reset, and the connecting rod 8012 is located in the second pipeline 8. Since the diameter of the connecting rod 8012 is much smaller than that of the first piston 8011 and the second piston 8013, the liquid in the second pipeline 8 can flow normally.

[0038] The working process of the present invention is as follows: Step 1: According to the tunnel site monitoring and experimental data, judge and select the high in-situ stress area of insensitive hard rock at the tunnel site, and carry out combined treatment of borehole fracturing and pressure relief.

[0039] Step 2: Drill holes with a diameter of about 100 mm on the working face of the deep insensitive hard rock tunnel. Transport the device of the present invention to the working face through the vehicle-mounted system 35. Extend the first pipeline 7 and the second pipeline 8 of the hydraulic fracturing system 37 to the bottom of the drill hole through the vehicle-mounted system 35 and the mobile platform 33. The preparation stage ends.

[0040] Step 3: Connect the 380V alternating current at the tunnel construction site, open the first valve 16, close the second valve 18, rotate the three-way valve 9, turn on the system control power supply in the liquid injection control system 12, and start the hydraulic fracturing high-pressure pump 14 to output water from the water storage tank 15 and inject it into the two packers 5 through the second pipeline 8 until the test pressure value suddenly increases, proving that the packers 5 have expanded in the drill hole to form a sealed fracturing section 1. Adjust the pressure regulating knob slowly to the zero position and turn off the hydraulic fracturing high-pressure pump 14. The sealing stage ends.

[0041] Step 4: Keep the first valve 16 open and the second valve 18 closed. Rotate the three-way valve 9 and start hydraulic fracturing and crack formation by inputting water from the first pipeline 7. Observe the value of the hydraulic fracturing measurement and control instrument 13. Continue to inject water for fracturing after the pressure peak drops to ensure full crack expansion. When the water pressure monitored by the hydraulic fracturing measurement and control instrument 13 is less than 5 MPa, adjust the pressure regulating knob slowly to the zero position and turn off the switch of the hydraulic fracturing high-pressure pump 14. The water injection fracturing stage ends.

[0042] Step 5: After opening the pressure relief valve 10 to drain water, close the first valve 16, open the second valve 18, and keep the three-way valve 9 in the same state. Continue to input the plugging liquid into the fracturing section 1 through the first pipeline 7 (the displacement when pumping the plugging agent is 10% higher than when pumping clear water to ensure that the hydraulic fracturing crack 6 opens and is convenient for the rapid increase of the net pressure in the crack). At the same time, add 40-60 mesh proppant 42, 20-40 mesh proppant 41, and 10-20 mesh proppant 40 sensitive minerals to the proppant filling port 11 in sequence. Control the mass ratio of the material to water at 1:10 or 1:12, and control the feeding time of each particle size of the sensitive mineral particles within 30-60 s. Observe the value of the hydraulic fracturing measurement and control instrument 13. If the pump injection pressure rises by 3-5 MPa, it indicates that the plugging effect is good. Adjust the pressure regulating knob slowly to the zero position and turn off the hydraulic fracturing high-pressure pump 14. The proppant filling stage ends. If the effect is not good, use a higher mass ratio of the material to water and repeat Step 5.

[0043] Step 6: After closing the first and second valves, open the pressure relief valve 10 to drain the remaining plugging liquid in the fracturing section 1 until the value of the hydraulic fracturing measurement and control instrument 13 drops back to zero. Then rotate the three-way valve 9 to drain the clear water in the two packers 5, and the packers 5 shrink. Move the mounting plate 19 to repeat Steps 3-5 for the un-fractured hole section in the hole.

[0044] Step 7: After the hydraulic fracturing and the filling of the sensitive mineral proppant are completed in the entire hard rock borehole, a heat-insulating and heat-reflecting nanomaterial layer 30 is laid on the inner surface of the borehole, and the thickness of the nanomaterial layer is around 10 mm. After laying, the vehicle-mounted system 35 and the mobile platform 33 are moved again to make the coaxial microwave radiator 31 reach the bottom of the borehole, and the hole is blocked with the ceramic fiber film 29 to prevent the microwave from escaping from the hole and affecting the heating effect.

[0045] Step 8: Connect the electricity at the tunnel construction site, turn on the water load device 23 to prevent the magnetron from overheating, with the water flow rate not less than 8 L / min. Turn on the filament power supply of the microwave emission system 36 to preheat the equipment. After the preheating is completed, turn on the high-frequency power supply 21 to emit microwaves of a certain power through the magnetron. Monitor the microwave transmission efficiency in real time through the microwave power meter 24 (if the transmission efficiency is low, adjust it through the manual three-pin tuner 25) to prevent low microwave transmission efficiency or microwave leakage. At the same time, the stress around the hard rock borehole can be observed in real time by burying stress gauges around the hard rock borehole, so as to further adjust the heating time (the default is 10 min) for different hard rock tunnels. Further, similar to the mobile operation of the hydraulic fracturing system 37, the microwave irradiation heating of the hole wall surfaces at different depths is completed.

[0046] Step 9: When multiple holes are arranged in the tunnel, the microwave emission system 36 and the hydraulic fracturing system 37 can work in parallel and synchronously, effectively improving the fracturing and pressure relief efficiency of the insensitive hard rock in the tunnel. At the same time, judge the heating fracturing and pressure relief effect of the insensitive hard rock in time through the stress monitoring of the surrounding rock 34. After the expected stress release effect is achieved, turn off the control power supplies of each system, disconnect the on-site electricity, and transport the device away through the vehicle-mounted system 35.

[0047] The embodiments described above are only descriptions of the preferred modes of the present invention, and do not limit the scope of the present invention. Without departing from the design spirit of the present invention, various deformations, variations, modifications, and substitutions made by those of ordinary skill in the art to the technical solutions of the present invention shall all fall within the protection scope determined by the claims of the present invention.

Claims

1. A rockburst prevention and control device for insensitive hard rocks based on the combination of hydraulic power and microwave, characterized in that: including a vehicle-mounted system (35), a hydraulic fracturing system (37), and a microwave transmitting system (36); The hydraulic fracturing system (37) and the microwave transmitting system (36) are respectively installed on the vehicle-mounted system (35) via a mobile platform (33); The hydraulic fracturing system (37) is used to first inject water into the insensitive hard rock borehole and form hydraulic fracturing cracks (6) on the circumferential wall surface of the insensitive hard rock borehole, and then inject sensitive mineral proppants to fill the hydraulic fracturing cracks (6); The microwave emission system (36) is used to move into the insensitive hard rock borehole after the sensitive mineral proppant is injected, and irradiate the inner wall surface of the insensitive hard rock borehole with microwaves, thereby heating the hydraulic fracturing crack (6) through the sensitive mineral proppant, forming a temperature difference in the insensitive hard rock borehole, and improving the fracturing performance of the hard rock.

2. The rockburst prevention and control device for insensitive hard rocks based on the combination of hydraulic power and microwave according to claim 1 is characterized in that: The microwave transmission system (36) comprises a box, a high-frequency power supply (21), a 15 kW microwave head (22), a water load device (23), a rectangular waveguide (26), a rectangular-circular conversion device (27), a coaxial transmission waveguide (28), and a coaxial microwave radiator (31); The box is mounted on the mobile platform (33), the high-frequency power supply (21) is mounted in the box, the 15 kW microwave head (22) is mounted on the top of the box, and the output end of the 15 kW microwave head (22) is sequentially connected to a water load device (23), a rectangular waveguide (26), a rectangular-circular conversion device (27), a coaxial transmission waveguide (28), and a coaxial microwave radiator (31); The coaxial microwave radiator (31) is adapted to the insensitive hard rock borehole and is used for being inserted into the insensitive hard rock borehole and emitting microwaves.

3. The rockburst prevention and control device for insensitive hard rocks based on the combination of hydraulic power and microwave according to claim 2 is characterized in that: The rectangular waveguide (26) is provided with a manual three-pin adjuster (25) to change the inductance value to tune the circuit; the rectangular waveguide (26) is provided with a microwave power meter (24) to monitor the microwave input and output power in real time.

4. The rockburst prevention and control device for insensitive hard rocks based on the combination of hydraulic power and microwave according to claim 1 is characterized in that: The hydraulic fracturing system (37) comprises a first pipeline (7), a second pipeline (8), a hole sealer 5 and a hydraulic fracturing high-pressure pump (14); The first pipeline (7) and the second pipeline (8) are arranged side by side, one end of each pipeline is used to be inserted into an insensitive hard rock borehole, and the other end is connected to the output end of the hydraulic fracturing high-pressure pump (14) through a three-way valve (9); A first pipeline through hole (2) is provided on the side of one end of the first pipeline (7) inserted into the insensitive hard rock borehole; two sealers 5 are provided on one end of the second pipeline (8) inserted into the insensitive hard rock borehole, and a fracturing section (1) of the insensitive hard rock borehole is located between the two sealers 5; the first pipeline through hole (2) is located in the fracturing section (1); The second pipeline (8) is used to inject water into the two sealers 5 through the hydraulic fracturing high-pressure pump (14), so that the two sealers 5 seal the fracturing section (1); The first pipeline (7) is used to first inject water into the fracturing section (1) through the hydraulic fracturing high-pressure pump (14), thereby forming hydraulic fracturing cracks (6) on the circumferential wall surface of the fracturing section (1), and then inject sensitive mineral proppants to fill the hydraulic fracturing cracks (6).

5. The rockburst prevention and control device for insensitive hard rocks based on the combination of hydraulic power and microwave according to claim 4 is characterized in that: The hydraulic fracturing system (37) further comprises a cabinet, a water storage tank (15) and a plugging liquid tank (17); The cabinet is mounted on the mobile platform (33), and the water storage tank (15) and the plugging liquid tank (17) are mounted in the cabinet; the water storage tank (15) is connected to one input end of the hydraulic fracturing high-pressure pump (14) via a first valve (16) and a pipeline, and the plugging liquid tank (17) is connected to the other input end of the hydraulic fracturing high-pressure pump (14) via a second valve (18) and a pipeline; The first pipe (7) is provided with a proppant filling port (11) for adding a sensitive mineral proppant into the first pipe (7); When sealing the fracturing section (1), the first valve (16) is opened, the second valve (18) is closed, and the three-way valve (9) is rotated to connect the hydraulic fracturing high-pressure pump (14) to the second pipeline (8) and the water storage tank (15), and the hydraulic fracturing high-pressure pump (14) injects water into the second pipeline (8); During hydraulic fracturing, the first valve (16) is opened, the second valve (18) is closed, and the three-way valve (9) is rotated so that the hydraulic fracturing high-pressure pump (14) is connected to the first pipeline (7) and the water storage tank (15), and the hydraulic fracturing high-pressure pump (14) injects water into the first pipeline (7); When the sensitive mineral proppant is filled, the second valve (18) is opened and the first valve (16) is closed. The hydraulic fracturing high-pressure pump (14) is connected to the first pipeline (7) and the plugging liquid tank (17). The sensitive mineral proppant is added through the proppant filling port (11), so that the sensitive mineral proppant mixed with the plugging liquid is injected into the fracturing section (1) and fills the hydraulic fracturing cracks (6).

6. The rockburst prevention and control device for insensitive hard rocks based on the combination of hydraulic power and microwave according to claim 4 is characterized in that: The output end of the hydraulic fracturing high-pressure pump (14) is connected to an output pipe, and the output pipe is connected to the first pipeline (7) and the second pipeline (8) through the three-way valve (9); a pressure relief valve (10) is provided on the output pipe to output the medium in the insensitive hard rock borehole.

7. The rockburst prevention and control device for insensitive hard rocks based on the combination of hydraulic power and microwave according to claim 4 is characterized in that: The hole sealer 5 comprises an annular elastic seal (502) and two sealing plates (501), the two sealing plates (501) are fixedly connected to the second pipe (8), and the annular elastic seal (502) is fixedly connected between the two sealing plates (501); The annular elastic sealing member (502) is annular and together with the two sealing plates (501) form an elastic chamber, and a second pipe through hole (3) is provided on the side of the second pipe (8) located in the elastic chamber; The second pipe (8) injects water into the elastic chamber through the second pipe through hole (3), causing the annular elastic sealing element (502) to expand outwards to abut against the inner wall surface of the insensitive hard rock borehole to form a seal.

8. The rockburst prevention and control device for insensitive hard rocks based on the combination of hydraulic power and microwave according to claim 4 is characterized in that: A blocking mechanism (801) is provided between the first pipeline (7) and the second pipeline (8), and the blocking mechanism (801) is located outside the fracturing section (1) and between the fracturing section (1) and the hydraulic fracturing high-pressure pump (14); The blocking mechanism (801) comprises a first piston (8011), a connecting rod (8012), a second piston (8013), a spring (8014), a connecting pipe (8015) and a side pipe (8016); the side of the second pipe (8) is fixedly connected to the side pipe (8016); the end of the first piston (8011) opposite to the second piston (8013) is fixedly connected to the connecting rod (8012); the side of the first pipe (7) and the side of the second pipe (8) are connected via the connecting pipe (8015); the first piston (8011) and the second piston (8013) are adapted to fit the connecting pipe (8015); the first piston (8011) is slidably located in the connecting pipe (8015); the second piston (8013) is slidably located in the side pipe (8016); the spring (8014) abutting against the second piston (8013) is arranged in the side pipe (8016); When a medium is injected into the first pipe (7), the first piston (8011) is pushed to move under the action of the internal pressure, so that the first piston (8011) crosses and blocks the second pipe (8), and the diameter of the connecting rod (8012) is smaller than that of the first piston (8011) and the second piston (8013).

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