Rock breaking device and method with cooperation of ultrasonic drilling and shield cutting

Abstract

The invention discloses a rock breaking device and method with cooperation of ultrasonic drilling and shield cutting, and relates to the technical field of hard rock efficient breaking. The rock breaking device comprises a shield tunneling machine cutting system and an ultrasonic vibration drilling device. During construction, the size of a target cutting face of a hard rock to be constructed is determined firstly, and parameters of the large-diameter pressure relief empty hole are determined in combination with rock mechanical parameters; then the ultrasonic vibration drilling device is fixedly arranged at the circle center of a cutter head of the shield tunneling machine, a large-diameter pressure relief empty hole is drilled through the ultrasonic resonance effect, the cutter of the shield tunneling machine cuts the rock after pressure relief, the ultrasonic vibration drilling rate and the cutter head cutting rate are synchronously controlled, and parallel operation of ultrasonic vibration drilling and shield cutting is achieved. According to the method, the radius and the length of the empty hole are quantitatively designed according to the elastic-plastic mechanics principle, so that a pressure relief area covering the whole section of the shield is formed on the periphery of the empty hole, stress redistribution and strength degradation of hard rock are achieved, meanwhile, the adaptive relation between empty hole parameters and the rock breaking speed is determined, and optimization of the rock breaking efficiency is achieved.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of hard rock efficient breaking, in particular to a rock breaking device and method for ultrasonic drilling and shield cutting cooperation. BACKGROUND

[0002] With the increase of mine service life and the decrease of shallow resources, mining gradually shifts to deep, and the amount of systematic roadway engineering increases, especially for hard rock mines, which generally have high rock strength, good integrity, high wear resistance and other characteristics, seriously affecting the mining operation and mining replacement. Therefore, it is of great significance to improve the rock breaking efficiency in hard rock strata.

[0003] In traditional rock breaking practice, drilling and blasting method and conventional mechanical tunneling are the most widely used methods, but due to the influence of rock hardness, burial depth and other objective conditions, the limitations of the two methods are gradually highlighted: the drilling and blasting method has slow hole forming speed and poor blasting efficiency; when facing high hardness rock mass, the conventional mechanical tunneling is prone to insufficient rock breaking capacity and rapid tool and material loss, both of which are difficult to meet the needs of rock breaking speed and cost control for efficient construction of mines.

[0004] To solve the problem of hard rock breaking and tunneling efficiency, the prior art attempts to combine advanced drilling with cutter head or cutting head to improve rock breaking capacity. The patent with publication number CN219809002U discloses a rock breaking device and tunneling machine, which sets a drill rod mounting seat in the center of the cutter head, and uses various types of jet flow drill rods to implement advanced pre-splitting, which improves the adaptability of hard rock working conditions to a certain extent and reduces the cutter load. However, this scheme lacks a special drilling structure that adapts to the characteristics of hard rock, and the operation cooperation between drilling and cutting needs to be improved. In addition, the pre-splitting or drilling operation does not accurately quantify the key parameters such as the radius and length of the hole, which cannot ensure that the hole perimeter forms a pressure relief zone covering the entire cross section of the shield; at the same time, the construction process lacks systematic operation specifications matching the hole parameters, resulting in unstable hard rock pre-pressure relief and weakening effect, and the cutter load is still large when the shield is subsequently cut, making it difficult to achieve the expected rock breaking efficiency and construction safety. SUMMARY

[0005] To solve the above problems, the present application discloses a rock breaking device and method for ultrasonic drilling and shield cutting cooperation, which optimizes the assembly structure and functional cooperation of the ultrasonic vibration drilling device and the shield machine, realizes efficient rock breaking, and reduces tool wear; at the same time, the hole radius and length are quantitatively designed based on the principle of elastic-plastic mechanics, so that the hole perimeter forms a pressure relief zone covering the entire cross section of the shield, realizes hard rock stress redistribution and strength degradation, and establishes the adaptive relationship between the hole parameters and the rock breaking speed, realizes the optimization of rock breaking efficiency.

[0006] The application discloses an ultrasonic drilling and shield cutting cooperative rock breaking device.

[0007] The shield cutting system comprises a circular ring-shaped cutter head, and the end surface of the cutter head is uniformly provided with a rolling cutter and a scraper in the circumferential direction.

[0008] The ultrasonic drilling device comprises an ultrasonic generator, a transducer, an amplitude transformation tool head, a vibration block, a pressure transmission block, a rock drilling rod and a rock drilling bit; the ultrasonic generator, the transducer, the amplitude transformation tool head, the vibration block and the pressure transmission block are integrated at the head of the ultrasonic drilling device and fixedly installed in the mounting groove; one end of the rock drilling rod is fixedly connected to the output end of the vibration block, and the other end is fixedly connected to the rock drilling bit; the ultrasonic generator is a vibration energy source; the transducer is arranged between the ultrasonic generator and the amplitude transformation tool head, the input end of the transducer is electrically connected to the ultrasonic generator, and the output end of the transducer is fixedly connected to the amplitude transformation tool head, so as to receive an electric signal and convert the electric signal into mechanical vibration and transmit the mechanical vibration to the amplitude transformation tool head; the output end of the amplitude transformation tool head is fixedly connected to the vibration block; the pressure transmission block is in a sleeve structure, the inner wall of the pressure transmission block forms a containing cavity matched with the vibration block, so as to wrap the vibration block; one end of the pressure transmission block is fixedly connected to the input end of the amplitude transformation tool head, and the other end is fixedly connected to the end of the rock drilling rod.

[0009] Preferably, a connecting sleeve is arranged on the outer periphery of the head of the ultrasonic drilling device, and the ultrasonic drilling device is fixedly installed in the mounting groove through the connecting sleeve; an elastic damping connecting piece is fixedly arranged on the outer side wall of the connecting sleeve, the elastic damping connecting piece is in an annular structure, the outer diameter of the elastic damping connecting piece is matched with the inner diameter of the mounting groove, and an elastic buffering surface is arranged at the bottom of the mounting groove.

[0010] Preferably, the ultrasonic drilling device further comprises a hollow water supply channel, the hollow water supply channel is arranged in the rock drilling rod in the axial direction of the rock drilling rod and is in communication with a water supply pipeline in the shield cutting system.

[0011] Preferably, the amplitude transformation tool head is in a stepped structure, the diameter of the input end is greater than that of the output end, the input end and the output end are connected through a conical transition section, and the transition section and the connecting portions of the two ends are processed with circular arc chamfers.

[0012] Preferably, the end surface of the rock drilling bit is provided with radial hard alloy cutting teeth.

[0013] The application further discloses a rock breaking method using the rock breaking device.

[0014] S1, determining the size of a target cutting surface of hard rock to be constructed, taking the size of the target cutting surface as a spatial constraint condition, and determining the radius and length of a large-diameter pressure relief empty hole in combination with rock mechanics parameters;

[0015] S2, the ultrasonic vibration drilling device is fixed at the center of the cutter head of the shield machine, ensuring that the center of the large-diameter pressure relief hole drilled by the ultrasonic vibration drilling device coincides with the center of the cutting section of the shield machine;

[0016] S3, the advance cylinder pushes the cutter head forward, driving the ultrasonic vibration drilling device to first extend into the target hard rock formation along the preset axis of the cutter head center of the shield machine, starting the ultrasonic vibration drilling device, adjusting the frequency of the ultrasonic generator to match the natural frequency of the target hard rock, inducing fatigue expansion of micro-cracks in the hard rock through ultrasonic resonance effect, and drilling a first large-diameter pressure relief hole at the center of the hard rock section;

[0017] S4, after the first large-diameter pressure relief hole is drilled, the cutter head is tightly attached to the hard rock section, the advance cylinder continues to push the cutter head forward, and the drilling continues, while the cutter head is driven to rotate, the cutter cuts the hard rock within the pressure relief ring, and the scraper synchronously cleans the rock debris generated by cutting, and the broken rock is transported out of the soil bin by the screw conveyor after entering the soil bin through the cutter head;

[0018] S5, after the single-cycle footage is completed, the advance cylinder drives the cutter head to continue advancing forward, and the ultrasonic vibration drilling device simultaneously drills the next large-diameter pressure relief hole, realizing continuous tunneling.

[0019] Preferably, in S1, the calculation formula of the radius r0 of the large-diameter pressure relief hole is:

[0020]

[0021] wherein, R x is the radius of the hard rock section; c is the cohesion of the rock mass; is the internal friction angle; σ0 is the original rock stress; c' is the reduced cohesion in the broken area around the hole after ultrasonic vibration.

[0022] Preferably, in S1, the calculation formula of the length L of the large-diameter pressure relief hole is:

[0023] L=k×K uv ×V0×t;

[0024] wherein, k is the advance coefficient, taking a value of 1.5-2; K uv is the ultrasonic vibration drilling pressure relief gain coefficient; V0 is the cutting speed of the shield foundation without ultrasonic vibration drilling; t is the cutting cycle time;

[0025] The calculation formula of the ultrasonic vibration drilling pressure relief gain coefficient K uv is:

[0026]

[0027] Wherein, η is the efficiency correction coefficient, taking the value of 0.6-1.0; c is the cohesion of the rock mass; σ0 is the in-situ rock stress; is the internal friction angle; r0 is the radius of the large-diameter pressure-relief empty hole; c' is the reduced cohesion in the broken zone around the hole after the ultrasonic vibration; R p is the radius of the pressure-relief zone of the large-diameter pressure-relief empty hole;

[0028] The radius R of the pressure-relief zone of the large-diameter pressure-relief empty hole p is calculated by the formula:

[0029]

[0030] Preferably, the formula for calculating the rock breaking speed V' of the ultrasonic-shield combined system and the rock breaking speed V is:

[0031] V' = K uv × V0;

[0032] V = V' × π × R x 2 ;

[0033] Wherein, V0 is the shield foundation cutting speed without ultrasonic vibration drilling; K uv is the pressure-relief gain coefficient of ultrasonic vibration drilling; R x is the radius of the hard rock cross section.

[0034] Compared with the prior art, the rock breaking device and method disclosed by the application has the following advantages:

[0035] (1) The high-power ultrasonic vibration drilling device is fixed at the center of the cutter head of the shield machine in the application, so that the center of the large-diameter pressure-relief empty hole drilled by the ultrasonic vibration drilling device coincides with the center of the cross section of the shield machine. The ultrasonic vibration drilling device generates high-frequency vibration, and a large-diameter pressure-relief empty hole is drilled in the hard rock by ultrasonic resonance, so that a pressure-relief zone covering the entire cross section of the shield machine is formed around the rock mass, and the rock mass is relieved; the cutter of the shield machine cuts the rock after pressure relief, and the drilling and cutting rates are controlled synchronously, so that drilling and cutting are carried out in parallel, and efficient rock breaking is realized by the ultrasonic vibration drilling and the shield machine.

[0036] (2) The application quantitatively designs the radius and length of the empty hole by the elastoplastic mechanics principle, so that a pressure-relief zone covering the entire cross section of the shield machine is formed around the edge of the empty hole, the stress of the hard rock is redistributed and the strength is deteriorated, and the adaptive relationship between the parameters of the empty hole and the rock breaking speed is established, so that the rock breaking efficiency is optimized.

[0037] (3) The present application introduces a leading coefficient k, so that the length of the hole is greater than the single cycle footage of the shield, and the drilling rod pushing rate of the ultrasonic vibration drilling device and the cutting rate of the cutter head of the shield machine are synchronously coupled according to the leading coefficient, so as to ensure that the hole is formed in advance, the rock mass cut by the rolling cutter and the scraper on the cutter head is in the pressure relief zone formed by the hole, the parallel operation of ultrasonic vibration drilling and shield cutting is realized, and the broken rock mass is transported out by the screw conveyor after entering the soil bin through the cutter head.

[0038] (4) The present application can verify whether the large-diameter pressure relief hole parameters meet the demand of the project on the hard rock excavation speed by calculating the rock excavation speed and the rock breaking speed, and can also provide technical guidance for rock breaking. BRIEF DESCRIPTION OF DRAWINGS

[0039] In order to more clearly illustrate the technical solutions of the embodiments of the present application or the prior art, the drawings needed in the following embodiment or prior art description will be briefly introduced. Obviously, the drawings in the following description are only some embodiments of the present application, and all other embodiments obtained by those skilled in the art without creative labor on the basis of these drawings also belong to the protection scope of the present application.

[0040] Figure 1 It is a schematic diagram of pressure relief surrounding rock partitioning for ultrasonic vibration drilling.

[0041] Figure 2 It is a front view of the cutter head.

[0042] Figure 3 It is a schematic diagram of the rock breaking device for ultrasonic drilling and shield cutting cooperation.

[0043] Figure 4 It is a structural diagram of the ultrasonic vibration drilling device.

[0044] In the figure: 1-large diameter pressure relief hole; 2-cutter head; 21-rolling cutter; 22-scraper; 3-ultrasonic vibration drilling device; 31-vibration block; 32-amplitude tool head; 33-hollow water supply channel; 34- rock drill rod; 35-ultrasonic wave generator; 36-pressure transmission block; 37- rock drill bit; 38-connection sleeve; 39-transducer; 4-pushing oil cylinder; 5-cutter head drive; 6-soil bin; 7-screw conveyor; 8-water supply pipeline. DETAILED DESCRIPTION

[0045] The specific embodiments of the present application will be briefly described below in combination with the drawings. Obviously, the described embodiments are only some embodiments of the present application, not all embodiments, and all other embodiments obtained by those skilled in the art without creative labor on the basis of the embodiments in the present application also belong to the protection scope of the present application.

[0046] Figures 1-4The preferred embodiments of the present application are shown, and are analyzed in detail.

[0047] As Figure 3 shown, an ultrasonic drilling and shield cutting rock breaking device, including a shield cutting system and an ultrasonic vibration drilling device 3, the ultrasonic vibration drilling device 3 is a core drilling execution component, and is coaxially assembled with the shield cutting system to form a cooperative structure for advanced drilling pressure relief and synchronous cutting and breaking, which is suitable for hard rock stratum.

[0048] The shield cutting system includes a circular cutter head 2, a push cylinder 4, a cutter head drive 5, a soil bin 6, a screw conveyor 7 and a water supply pipeline 8. As Figure 2 shown, the cutter head 2 is a cutting core component, made of Q345 steel, and the end face of the cutter head 2 cutting body is respectively distributed with a rolling cutter 21 and a scraper 22 along the circumferential direction. The rolling cutter 21 is a 17-inch single-blade rolling cutter 21, and the cutter ring is made of WC-Co hard alloy, protruding 15mm from the end face of the cutter head 2, used for hard rock breaking; the scraper 22 is made of wear-resistant alloy material, with a blade edge hardness of ≥HRC60, protruding 10mm from the end face of the cutter head 2, used for cleaning the rock debris after cutting. The cutter head 2 has a coaxial installation groove in the center area. The push cylinder 4 adopts a double-cylinder synchronous driving structure, used to push the cutter head 2 to feed smoothly along the tunneling direction, and the feeding speed can be adjusted. The cutter head drive 5 is a hydraulic motor, which drives the cutter head 2 to rotate through gear transmission, and the output torque is adapted to the hard rock cutting demand. The soil bin 6 has a volume of 1.2m 3 , and the inner wall is paved with a 10mm-thick wear-resistant lining plate, used for temporarily storing broken rock blocks to avoid wall wear. The screw conveyor 7 has a diameter of 400mm, and the blade is made of wear-resistant steel, with a conveying capacity of ≥25m 3 / h, and an inclination angle of 15°, which can quickly convey the rock debris in the soil bin 6 to the outside of the shield machine, ensuring continuous cutting operation.

[0049] As Figure 4As shown, the ultrasonic vibration drilling device 3 comprises an ultrasonic generator 35, a transducer 39, an amplitude tool head 32, a vibration block 31, a pressure transmission block 36, a rock drill rod 34 and a rock drill bit 37. The ultrasonic generator 35, the transducer 39, the amplitude tool head 32, the vibration block 31 and the pressure transmission block 36 are integrated in the head of the ultrasonic vibration drilling device 3 and fixedly installed in the mounting groove. One end of the rock drill rod 34 is fixedly connected to the output end of the vibration block 31, and the other end is fixedly connected to the rock drill bit 37. Specifically, the outer periphery of the head of the ultrasonic vibration drilling device 3 is sleeved with a connecting sleeve 38, and the head of the ultrasonic vibration drilling device 3 and the connecting sleeve 38 are fixedly connected by bolts. The ultrasonic vibration drilling device 3 is coaxially fastened with the mounting groove through the connecting sleeve 38. Specifically, bolt positioning holes are processed on the inner wall of the mounting groove, and connecting holes matching the bolt positioning holes are also provided on the connecting sleeve 38. The connecting sleeve 38 is fixedly connected with the mounting groove by fixing bolts, ensuring that the coaxiality of the ultrasonic vibration drilling device 3 and the cutter head 2 is ≤0.05mm. The connecting sleeve 38 is made of 45 steel, and a nitrile rubber elastic damping connecting piece is fixedly arranged on the outer side wall. The elastic damping connecting piece has an annular structure, the outer diameter of which is adapted to the inner diameter of the mounting groove, and the elastic damping connecting piece is fixed to the outer side wall of the connecting sleeve 38 by interference fit or adhesive bonding to form a vibration isolation layer between the connecting sleeve 38 and the inner wall of the mounting groove. The bottom of the mounting groove is also provided with a nitrile rubber elastic buffer surface, which together with the elastic damping connecting piece on the outer side of the connecting sleeve 38 forms a double vibration isolation to prevent the ultrasonic vibration from being transmitted to the cutter head 2 and causing damage to the cutter head 2. The output frequency of the ultrasonic generator 35 can be adjusted in the range of 25-30kHz to adapt to the natural frequency of different intensity hard rocks. The frequency adjustment accuracy is ±0.5kHz, the rated power is 40kW, and the ultrasonic generator 35 is connected to the explosion-proof power supply system of the shield tunneling machine through an electric lead to provide energy for vibration. When the compressive strength of hard rock is 60-80MPa, the output frequency is adapted to 25-28kHz; when the compressive strength of hard rock is 80-100MPa, the output frequency is adapted to 28-30kHz, ensuring resonance with the natural frequency of hard rock. The transducer 39 is a disc stack structure composed of alternating stacked piezoelectric ceramic sheets and metal electrode sheets, which is adapted to the working frequency of the generator. The transducer 39 is provided with a protective shell outside for wrapping the alternating stacked disc-shaped piezoelectric ceramic sheets and brass metal electrode sheets inside. The transducer 39 is arranged between the ultrasonic generator 35 and the amplitude tool head 32, the input end of which is electrically connected to the ultrasonic generator 35, and the output end is rigidly fixed to the amplitude tool head 32 by screwing. During the screwing process, the end face of the transducer 39 is tightly fitted with the end face of the input end of the amplitude tool head 32 to avoid energy loss due to gaps when high-frequency vibration is transmitted. The transducer 39 is used to receive high-frequency electric signals and convert the electric signals into high-frequency mechanical vibrations to be transmitted to the amplitude tool head 32, ensuring that the electric energy output by the ultrasonic generator 35 is stably converted into the mechanical vibration required for rock breaking, and at the same time, the vibration stability is strengthened by the stacked structure to avoid amplitude attenuation caused by energy fluctuation during hard rock drilling.The amplitude tool head 32 is made of high-hardness magnesium-aluminum alloy and has a stepped shape along the vibration transmission direction. The input end has a larger diameter than the output end. The input end and the output end are connected by a conical transition section. The transition section has a length of 60 mm and is provided with a radius of 5 mm arc chamfer at the transition to effectively avoid vibration stress concentration and ensure stable transmission of the amplitude. The amplitude tool head 32 can efficiently converge vibration energy and amplify the amplitude to ensure that the rock drill bit 37 can drill the large-diameter pressure-relief empty hole 1 with sufficient vibration intensity, create pressure-relief conditions for subsequent shield cutting, and reduce the dispersion loss of vibration energy in the transmission process. The transmission block 36 has a sleeve structure and is made of 40Cr with a surface hardness of HRC 50-55. The transmission block 36 is used to uniformly transmit the vibration energy output by the ultrasonic generator 35 to the vibration block 31. The inner wall of the transmission block 36 forms a containing cavity that is adapted to the vibration block 31 to wrap the vibration block 31. One end of the transmission block 36 is fixedly connected with the input end of the amplitude tool head 32, and the other end is fixedly connected with the end of the rock drill rod 34 that is connected with the vibration block 31. The transmission block 36 indirectly and rigidly connects the amplitude tool head 32 and the rock drill rod 34 to ensure synchronous transmission of vibration energy and form a transmission channel for the vibration main load. Specifically, the end of the transmission block 36 that is connected with the amplitude tool head 32 is fixed by screwing and then fastened by a locking structure (such as a locking nut or spot welding) to avoid loosening caused by high-frequency vibration. The vibration block 31 is made of titanium alloy and is placed in the containing cavity of the transmission block 36. The vibration block 31 is a vibration transmission buffer component and is fixedly installed on the output end of the amplitude tool head 32. The connection mode can be integrated (such as forging) or fixed by screwing to ensure that the vibration energy amplified by the amplitude tool head 32 is stably transmitted to the vibration block 31. The rock drill rod 34 is a vibration transmission and drilling carrier and is fixedly connected with the vibration block 31 by screwing. After screwing, the rock drill rod 34 is fastened by torque to avoid relative rotation during drilling. The rock drill rod 34 is provided with a hollow water supply channel 33 along the axial direction. One end of the hollow water supply channel 33 is connected with the water supply pipeline 8 of the shield machine cutting system through a quick connector, and the other end extends to the rock drill bit 37 and is connected with the water injection holes on the end face of the rock drill bit 37 to form a complete water supply path. The water supply pipeline 8 is connected with an external high-pressure water supply pump of the shield machine to continuously deliver water flow to the drilling area while discharging rock debris. The end of the hollow water supply channel 33 that is connected with the water supply pipeline 8 is led out from the end of the rock drill rod 34 that is close to the vibration block 31. The rock drill rod 34 is made of 27SiMn alloy steel pipe, and the outer wall of the rock drill rod 34 is coated with a wear-resistant coating with a thickness of 0.1 mm and made of WC to prolong the service life. The rock drill bit 37 is a drilling executive component. The rock drill bit 37 is made of YG8 hard alloy and is uniformly provided with four water injection holes on the end face. The rock drill bit 37 is connected with the hollow water supply channel 33. The end face of the rock drill bit 37 is provided with eight radial cutting teeth with a tooth spacing of 10 mm and a hardness of ≥HRC 65 to meet the drilling requirements of hard rock. The rock drill rod 34 and the rock drill bit 37 need to be selected according to the size requirements of the large-diameter pressure-relief empty hole 1.

[0050] As shown in Figure 1 , the hard rock roadway section is circular, and the radius is R x , and the large-diameter pressure relief empty hole 1 with a radius of r0 is drilled by using the ultrasonic vibration drilling device 3. The pressure relief ring range radius is R P , which is composed of a broken zone and a plastic zone.

[0051] Select a hard rock roadway in a mine as a test section, and the specific rock breaking method includes the following steps:

[0052] S1, determine the target cutting surface size of the hard rock to be constructed, and determine the radius and length of the large-diameter pressure relief empty hole 1 as a spatial constraint condition combined with rock mechanics parameters, to ensure that the large-diameter pressure relief empty hole 1 effectively plays a role in pressure relief and weakening of hard rock within the cutting surface range.

[0053] The calculation formula of the radius of the large-diameter pressure relief empty hole 1 is: ; In the formula, , the radius of the hard rock section is 3m; , the cohesion of the rock mass is 20MPa; , the internal friction angle of the rock mass is 30°; , the original rock stress is 60MPa; , the reduced cohesion in the broken zone around the hole after ultrasonic vibration is 5MPa; calculation can obtain the radius of the large-diameter pressure relief empty hole 1 0.2m.

[0054] The cohesion and internal friction angle of the rock mass are obtained by fitting the Mohr-Coulomb strength criterion according to the test data of the triaxial shear test of the target hard rock core obtained by drilling core on site; the original rock stress is measured on site in the target hard rock formation by using the in-situ stress testing method (such as hydraulic fracturing method or stress relief method); the radius of the hard rock section is determined according to the shield cutting section size required by the engineering design; the reduced cohesion in the broken zone around the hole after ultrasonic vibration is determined by the core shear test under the action of ultrasonic vibration in the laboratory, or the value is taken from the test data of similar hard rock under the same ultrasonic parameters.

[0055] The calculation formula of the length L of the large-diameter pressure relief empty hole 1 is:

[0056] L=k×K uv ×V0×t;

[0057] In the formula, k is the advance coefficient, which is 1.5; K uv ​K is the pressure relief gain coefficient of the ultrasonic vibration drilling; V0 is the cutting speed of the shield foundation without ultrasonic vibration drilling, which is 0.5 m / h; t is the cutting cycle time, which is 4 h;

[0058] K is the pressure relief gain coefficient of the ultrasonic vibration drilling uv The calculation formula is as follows:

[0059]

[0060] In the formula, η is the efficiency correction coefficient, which is 0.8; c is the cohesion of the rock mass; σ0 is the original rock stress; is the internal friction angle; r0 is the radius of the large-diameter pressure relief hole 1; c' is the reduced cohesion in the broken zone around the hole after the ultrasonic vibration; R p is the radius of the pressure relief zone of the large-diameter pressure relief hole 1;

[0061] R is the radius of the pressure relief zone of the large-diameter pressure relief hole 1 p The calculation formula is as follows:

[0062]

[0063] The calculation formula of the rock excavation speed V' and the rock breaking speed V of the ultrasonic-shield composite system is as follows:

[0064] V' = K uv × V0;

[0065] V = V' × π × R x 2 ;

[0066] In the formula, V0 is the cutting speed of the shield foundation without ultrasonic vibration drilling; K uv is the pressure relief gain coefficient of the ultrasonic vibration drilling; R x is the radius of the pressure relief zone of the large-diameter pressure relief hole 1.

[0067] The calculation shows that the pressure relief gain coefficient K uv of the ultrasonic vibration drilling is 1.32, the length L of the large-diameter pressure relief hole 1 is 3.96 m, the rock excavation speed V' of the ultrasonic-vibration composite system is 0.66 m / h, the rock breaking speed V is 18.65 m 3 / h, and the theoretical maximum monthly cycle footage is 475 m.

[0068] S2, the ultrasonic vibration drilling device 3 is fixedly arranged at the center of the cutter head 2 of the shield machine, so that the center of the large-diameter pressure relief hole 1 drilled by the ultrasonic vibration drilling device 3 coincides with the center of the cutting section of the shield machine.

[0069] S3, the advancing oil cylinder 4 pushes the cutter head 2 forward, drives the ultrasonic vibration drilling device 3 to extend into the target hard rock stratum along the preset axis of the cutter head 2 of the shield machine, starts the ultrasonic vibration drilling device 3, adjusts the frequency of the ultrasonic wave generator 35 to 25 kHz and the power to 40 kW, matches the natural frequency of the target hard rock, induces the fatigue expansion of the micro-cracks in the hard rock through the ultrasonic resonance effect, drills the first large-diameter pressure relief hole 1 at the center of the hard rock section, controls the vibration time and adjusts the parameter of the amplitude tool head 32, selects the amplitude amplification coefficient to be 3:1, so that the stress redistribution of the rock mass around the large-diameter pressure relief hole 1 occurs. In the process of drilling the large-diameter pressure relief hole 1, the hollow water supply channel 33 of the ultrasonic vibration drilling device 3 is supplied with water through the water supply pipeline 8 connected to the shield machine, the drill cuttings in the drilling area are discharged, and the temperature in the drilling area is maintained stable to ensure the continuous transmission of ultrasonic vibration energy.

[0070] S4, after the first large-diameter pressure relief hole 1 is drilled, the cutter head 2 is tightly attached to the hard rock section, the advancing oil cylinder 4 continues to push the cutter head 2 forward, continues to drill, and the cutter head drive 5 drives the cutter head 2 to rotate while drilling, the roller cutter 21 cuts the hard rock in the pressure relief ring range, the scraper 22 synchronously cleans the rock cuttings generated by cutting, the drill rod advancing rate of the ultrasonic vibration drilling device 3 and the cutting rate of the cutter head 2 of the shield machine are synchronously coupled and controlled according to the advance coefficient k, the large-diameter pressure relief hole 1 is ensured to be formed in advance, the rock mass cut by the roller cutter 21 and the scraper 22 on the cutter head 2 of the shield machine is in the pressure relief zone formed by the hole, the parallel operation of ultrasonic vibration drilling and shield cutting is realized, and the broken rock blocks enter the soil chamber 6 through the cutter head 2 and are transported out by the screw conveyor 7.

[0071] S5, after the single-cycle footage is completed, the advancing oil cylinder 4 drives the cutter head 2 to continue to advance forward, the ultrasonic vibration drilling device 3 synchronously drills the next large-diameter pressure relief hole 1, and continuous tunneling is realized.

[0072] The above description of the disclosed embodiments enables a person skilled in the art to implement and use the present application. Various modifications to these embodiments will be apparent to those skilled in the art, and the general principles defined herein can be implemented in other embodiments without departing from the spirit and scope of the present application. Therefore, the present application will not be limited to these embodiments shown herein, but will conform to the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. An ultrasonic drilling and shield tunneling cutting cooperative rock breaking device, characterized in that, The shield machine cutting system and the ultrasonic vibration drilling device (3) are included. The shield machine cutting system includes a circular cutter head (2), and the end surface of the cutter head (2) is uniformly distributed with a rolling cutter (21) and a scraper (22) in the circumferential direction; and a mounting groove is arranged in the center area of the cutter head (2). The ultrasonic vibration drilling device (3) includes an ultrasonic generator (35), a transducer (39), an amplitude tool head (32), a vibration block (31), a pressure transmission block (36), a rock drilling rod (34) and a rock drilling bit (37); the ultrasonic generator (35), the transducer (39), the amplitude tool head (32), the vibration block (31) and the pressure transmission block (36) are integrated in the head of the ultrasonic vibration drilling device (3) and fixedly installed in the mounting groove; one end of the rock drilling rod (34) is fixedly connected to the output end of the vibration block (31), and the other end is fixedly connected to the rock drilling bit (37); the ultrasonic generator (35) is a vibration energy source, the transducer (39) is arranged between the ultrasonic generator (35) and the amplitude tool head (32), the input end of the transducer (39) is electrically connected to the ultrasonic generator (35), and the output end of the transducer (39) is fixedly connected to the amplitude tool head (32) to receive an electric signal and convert the electric signal into mechanical vibration and transmit the mechanical vibration to the amplitude tool head (32); the output end of the amplitude tool head (32) is fixedly connected to the vibration block (31); the pressure transmission block (36) has a sleeve structure, the inner wall of the pressure transmission block (36) forms a containing cavity matched with the vibration block (31) to wrap the vibration block (31), one end of the pressure transmission block (36) is fixedly connected to the input end of the amplitude tool head (32), and the other end is fixedly connected to the end of the rock drilling rod (34).

2. The rock breaking device of claim 1, wherein, The head of the ultrasonic vibration drilling device (3) is provided with a connecting sleeve (38) outside the periphery, the ultrasonic vibration drilling device (3) is fixedly installed in the mounting groove through the connecting sleeve (38); an elastic damping connecting piece is fixedly arranged on the outer side wall of the connecting sleeve (38), the elastic damping connecting piece has an annular structure, the outer diameter of the elastic damping connecting piece is matched with the inner diameter of the mounting groove; and the bottom of the mounting groove is provided with an elastic buffer surface.

3. The rock breaking device of claim 1, wherein, The ultrasonic vibration drilling device (3) further includes a hollow water supply channel (33), the hollow water supply channel (33) is arranged in the rock drilling rod (34) in the axial direction of the rock drilling rod (34) and is communicated with the water supply pipeline (8) in the shield machine cutting system.

4. The rock breaking device of claim 1, wherein, The amplitude tool head (32) has a stepped structure, the diameter of the input end is greater than that of the output end, the input end and the output end are connected through a conical transition section, and the transition section and the connection portions of the two ends are chamfered with circular arcs.

5. The rock breaking device of claim 1, wherein, The end surface of the rock drilling bit (37) is provided with hard alloy cutting teeth in a radial manner.

6. A method for rock breaking using the rock breaking device of claim 1-5, characterized in that, The method includes the following steps: S1, determining the target cutting surface size of the hard rock to be constructed, taking the target cutting surface size as a spatial constraint condition, and determining the radius and length of the large-diameter pressure relief empty hole (1) in combination with rock mechanics parameters; S2, the ultrasonic vibration drilling device (3) is fixedly arranged at the center of the cutter head (2) of the shield machine, so that the center of the large-diameter pressure relief empty hole (1) drilled by the ultrasonic vibration drilling device (3) is coincided with the center of the cutting surface of the shield machine. S3, the advancing oil cylinder (4) pushes the cutter head (2) to advance, drives the ultrasonic vibration drilling device (3) to first extend into the target hard rock stratum along the preset axis of the shield machine cutter head (2) center, starts the ultrasonic vibration drilling device (3), adjusts the frequency of the ultrasonic wave generator (35) to match the natural frequency of the target hard rock, induces the fatigue expansion of the internal micro-cracks of the hard rock through the ultrasonic resonance effect, and drills the first large-diameter pressure relief empty hole (1) at the center of the hard rock section; S4, after the first large-diameter pressure relief empty hole (1) is drilled, the cutter head (2) is tightly attached to the hard rock section, the advancing oil cylinder (4) continues to push the cutter head (2) to advance, and continues to drill, while the cutter head (2) is rotated by the cutter head drive (5), the roller cutter (21) cuts the hard rock in the pressure relief ring range, and the scraper (22) synchronously cleans the rock debris generated by cutting, and the broken rock blocks enter the soil bin (6) through the cutter head (2) and are transported out by the screw conveyor (7); S5, after the single-cycle footage is completed, the advancing oil cylinder (4) drives the cutter head (2) to continue to advance, the ultrasonic vibration drilling device (3) synchronously drills the next large-diameter pressure relief empty hole (1), and continuous tunneling is realized.

7. The method of claim 6, wherein, In S1, the calculation formula of the radius r0 of the large-diameter pressure relief empty hole (1) is: where R x is the radius of the hard rock section; c is the cohesion of the rock mass; is the internal friction angle; σ0 is the in-situ rock stress; c' is the reduced cohesion in the broken zone around the borehole after ultrasonic vibration.

8. The method of claim 6, wherein, In S1, the calculation formula of the length L of the large-diameter pressure relief empty hole (1) is: L = k x K uv x V0 x t; In the formula, k is a leading coefficient, and takes a value of 1.5-2; K uv is an ultrasonic vibration drilling pressure relief gain coefficient; V0 is a shield foundation cutting speed without ultrasonic vibration drilling; and t is a cutting cycle time. Ultrasonic vibration drilling pressure relief gain coefficient K uv The calculation formula is: In the formula, η is the efficiency correction coefficient, with a value of 0.6-1.0; c is the cohesion of the rock mass; σ0 is the in-situ rock stress; is the internal friction angle; r0 is the radius of the large-diameter pressure-relief empty hole (1); c' is the reduced cohesion in the broken zone around the drill hole after the ultrasonic vibration is applied; R p is the radius of the pressure-relief zone of the large-diameter pressure-relief empty hole (1); Large diameter pressure relief hole (1) pressure relief zone radius R p The calculation formula is:

9. The method of claim 8, wherein, The calculation formula of the rock breaking speed V of the ultrasonic-shield composite system is: V' = K uv x V0; V = V' x π x R x 2 ; In the formula, V0 is the shield foundation cutting speed without ultrasonic vibration drilling; K uv is the pressure relief gain coefficient of ultrasonic vibration drilling; R x is the hard rock section radius.

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