A method for protecting underground engineering from blasting by strengthening self-fragmentation of rock mass

Abstract

The present invention discloses a method for protecting underground engineering from intrusion and explosion by strengthening self-fragmentation of rock mass, which belongs to the technical field of protection against intrusion and explosion of underground engineering. The method comprises a number of fracturers evenly arranged in the protection area, a number of fracture disks also being arranged on the fracturers, and the number of fracture disks being divided into multiple sections. The fracturers are then arranged after the positions of the fracturers are determined by calculation and experiment, and a vibration velocity sensor is arranged. Multiple groups of explosive fractures are carried out in sequence according to the explosion impact intensity sensed by the vibration velocity sensor until the explosion impact does not cause damage to the underground engineering. This method of carrying out batch explosive fractures after monitoring in sequence can form multiple layers of fracture surfaces, better hinder the propagation of the explosion stress wave, and the rock mass crushing between the fracture surfaces formed by the blasting of small-amount interval charge can further enhance the attenuation effect of the explosion impact vibration. At the same time, the fracture surfaces and the crushed rock mass can also suppress the penetration of the projectile, effectively protecting the underground engineering.

Description

Technical Field

[0001] The present invention belongs to the technical field of underground engineering anti-explosion protection, and in particular relates to a method for strengthening the anti-explosion protection of underground engineering with self-fragmentation of rock masses. Background Art

[0002] The research and application of anti-blast measures for underground projects continues to advance. Structural anti-blast protection measures primarily focus on rationally designing lining structures and strengthening lining strength. These structural anti-blast measures are generally only effective against small, minor explosions, and once the protective measures are destroyed, they become difficult to re-use. For example, a steel plate-steel skeleton-polyurethane foam composite sandwich panel offers advantages such as lightweight, high strength, quick construction, and frost resistance and insulation, but its anti-blast effect is limited. Conventional underground project surrounding rock anti-blast protection measures primarily focus on anchor reinforcement and cable reinforcement. These basic engineering surrounding rock anti-blast measures are implemented during construction and are difficult to modify or reinforce subsequently, making it difficult to update and improve their anti-blast capabilities. Whether using anchor reinforcement or strengthening the structure and lining, the construction process for underground project anti-blast protection is complex, requires high technical requirements, and requires a long construction time. Summary of the Invention

[0003] In view of the defects of the existing anti-explosion protection construction process being relatively complex, requiring high technical skills and taking a long time to construct, the purpose of the present invention is to propose a reinforced rock mass self-fragmentation underground engineering anti-explosion protection method.

[0004] In order to achieve the above-mentioned purpose, the technical solution adopted by the present invention is:

[0005] A method for protecting an underground engineering project from blasting by strengthening self-fragmentation of rock mass, the method comprises the following steps:

[0006] S1: Calculate the size of the rupture disk on the rupture device and the locations of the mounting holes of several anti-explosion protection structures according to the protection area;

[0007] S2: After determining the depth of the mounting holes, drilling is performed. The projections of the mounting holes for mounting the crackers on the horizontal plane are arranged in multiple rows, and the mounting holes in two adjacent rows are staggered.

[0008] S3: Installing a fracturing device in the mounting hole and arranging the plurality of fracturing disks on the fracturing device in sections, wherein the first fracturing disk located at the uppermost side in the vertical direction is used to form a permanent fracturing zone, and the remaining fracturing disks are used to form immediate fracturing zones;

[0009] S4: Deploying a vibration velocity sensor on the inner wall of a mounting hole corresponding to each rupture disk in the immediate rupture zone, and setting a threshold for triggering rupture disk explosion for the vibration velocity sensor;

[0010] S5: Explosively fracture the first fracture disk on the fracture device to obtain a permanent fracture zone;

[0011] S6: When the explosion impact intensity sensed by the corresponding vibration velocity sensor reaches the set explosion threshold, the remaining vertically distributed fracturing disks are sequentially subjected to segmented explosive fracturing to form deeper instant fracturing zones until the explosion impact no longer causes damage to the underground engineering.

[0012] The fracturing device described in the aforementioned steps includes a plurality of fracturing disks distributed at equal or proportional distances and a conduit extending in a vertical direction. The conduit is connected to the center of the plurality of fracturing disks. An explosive chamber for placing explosives is provided in the fracturing disks. A first detonating cord for igniting the explosives in the explosive chamber is provided in the conduit. Fracturing disks at the same level on different fracturing devices are located in the same horizontal plane.

[0013] As an improvement to the above technical solution, after the explosion of the first fracturing disk in S5, a secondary fracturing is provided to be broken by explosives. The specific process of the secondary fracturing is as follows:

[0014] S51: After the first stage of the cracker explosion is completed, secondary mounting holes are drilled at positions staggered with the plurality of mounting holes on each row;

[0015] S52: Install explosives in the secondary installation hole;

[0016] S53: Perform secondary blasting to break up the rock mass between the fissure layers;

[0017] S54: Grouting is performed on the broken crack surface formed by the second cracking through the secondary installation hole.

[0018] As a further improvement of the above technical solution, the distance between adjacent mounting holes in S1 is determined by the coverage of the rock fracture surface after the fracturing disk is blasted.

[0019] As a further improvement of the above technical solution, the vibration velocity sensor in S4 is arranged in the immediate fracturing zone and on the inner wall of the mounting hole corresponding to the uppermost fracturing disk in each fracturing disk in the horizontal direction, and the maximum value of the spacing and row spacing of the vibration velocity sensors is less than or equal to the minimum size of the protected underground project on the plane.

[0020] As a further improvement of the above technical solution, the drilling depth of the secondary installation hole in S51 is from the ground surface to the midpoint of the two lowest rupture disks in the first section of rupture disks.

[0021] As a further improvement of the above technical solution, in S52, the explosive charging is completed in a small amount interval charging manner.

[0022] As a further improvement of the above technical solution, polyurea slurry is used for grouting in S54.

[0023] As a further improvement of the above technical solution, the chamber inside the rupture disk includes an annular explosive chamber arranged on the periphery of the rupture disk and used to bury explosives, and an annular detonator chamber arranged between the explosive chamber and the conduit and used to lay detonators. The explosive chamber and the detonator chamber are connected, and an annular second detonating cord is arranged in the explosive chamber, and the detonating joint of the detonator and the detonating joint of the second detonating cord are both connected to the first detonating cord.

[0024] As a further improvement of the above technical solution, the multiple rupture disks on the same catheter completely correspond to each other in the vertical direction.

[0025] The invention provides a method for protecting underground engineering from blasting by strengthening self-fragmentation of rock masses, which can achieve the following beneficial effects:

[0026] (1) The method adopts active explosive fracturing for protection. It only requires burying a number of fracturing devices in installation holes distributed in a plum blossom shape in the protection area of ​​the underground project to perform explosive fracturing. The technical requirements are relatively low, the construction process is simple, the construction time is shortened, and the purpose of reducing the transmission intensity of the explosive load and improving the anti-penetration and anti-explosion capabilities of the cavern can be achieved simply and quickly.

[0027] (2) Multiple groups of explosive fracturing are carried out in sequence according to the explosion impact intensity sensed by the vibration velocity sensor until the explosion impact does not cause damage to the underground project. This method of conducting batch explosive fracturing after monitoring can form multiple layers of fracture surfaces, which can better hinder the propagation of the explosion stress wave. The rock mass fragmentation between the fracture surfaces formed by the small-volume interval charge blasting can further enhance the attenuation effect of the explosion impact vibration. At the same time, the fracture surface and the broken rock mass can also inhibit the penetration of the projectile, effectively protecting the underground project.

[0028] The above description is only an overview of the technical solution of the present invention. In order to more clearly understand the technical means of the present invention, it can be implemented in accordance with the contents of the specification. In order to make the above and other purposes, features and advantages of the present invention more obvious and easy to understand, the following preferred embodiments are specifically cited and described in detail with reference to the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1 It is an axonometric view of the single-layer structure cracker of the present invention.

[0030] Figure 2 It is a front view of the single-layer structure cracker of the present invention.

[0031] Figure 3 It is a cross-sectional view of the single-layer structure cracker of the present invention.

[0032] Figure 4 It is a schematic diagram of the fracture range of a single-layer structure fracturer in the surrounding rock.

[0033] Figure 5 This is a front view of a multi-layer equidistant structure cracker.

[0034] Figure 6 It is an axonometric drawing of a multi-layer equidistant structure of a cracker.

[0035] Figure 7 This is a front view of a multi-layer proportional distance structure cracker.

[0036] Figure 8 It is an axonometric drawing of a multi-layer scale distance structure of a cracker.

[0037] Figure 9 It is a cross-sectional schematic diagram showing the layout of several fracturing devices in the protection area of ​​an underground project.

[0038] Figure 10 It is an axonometric diagram of the primary fracturing range of a multi-layer equidistant structure fracturist within the protection range of an underground engineering project.

[0039] Figure 11 yes Figure 10 Projection view of the fracture range shown on the horizontal plane.

[0040] Figure 12 yes Figure 10 Schematic cross-sectional view of the even-numbered rows of crackers on the vertical plane.

[0041] Figure 13 It is an axonometric diagram of the secondary mounting hole used for secondary cracking.

[0042] Figure 14 yes Figure 13 Schematic top view of .

[0043] Figure 15 It is a schematic diagram of the first implementation method of the broken crack surface and the crack surface after multi-stage secondary fracturing.

[0044] Figure 16 It is a schematic diagram of a second embodiment of a broken crack surface and a crack surface after multi-stage secondary fracturing.

[0045] Among them: 1. Fracture device; 2. Fracture disk; 3. Conduit; 4. Explosive chamber; 5. Detonator chamber; 601. First detonating cord; 602. Second detonating cord; 7. Mounting hole; 701. Secondary mounting hole; 8. Fracture surface; 9. Underground engineering; 10. Vibration velocity sensor; 11. Broken fracture surface. DETAILED DESCRIPTION

[0046] The various aspects and exemplary embodiments of the present invention will be described in detail below. In the detailed description below, many specific details are set forth in order to provide a comprehensive understanding of the present invention. However, it will be apparent to those skilled in the art that the present invention can be implemented without some of these specific details. The following description of the embodiments is merely intended to provide a better understanding of the present invention by illustrating examples of the present invention. In the drawings and the following description, at least some of the well-known structures and technologies are not shown in order to avoid unnecessary ambiguity in the present invention; and, for the sake of clarity, the sizes of some structures may be exaggerated. The features, structures or characteristics described below may be combined in any suitable manner in one or more embodiments. In addition, the terms "first or I", "second or II", "third or III", etc. are used for descriptive purposes only and are not to be understood as indicating or implying relative importance.

[0047] The directional words appearing in the following description are all directions shown in the figures, and do not limit the specific structure of the present invention. In the description of the present invention, it should also be noted that, unless otherwise clearly specified and limited, the terms "setting", "installation" and "connection" should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral connection; it can be directly connected or indirectly connected. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to the specific circumstances. In the present invention, the direction in which the underground project extends to the ground is the vertical direction, and the direction perpendicular to the vertical direction is the horizontal direction.

[0048] A method for protecting underground engineering projects against blasting by reinforced self-fragmenting rock masses mainly utilizes reinforced self-fragmenting rock masses for underground engineering projects against blasting by evenly arranged protective structures in the protection area to explosively fracture the surrounding rock of the underground engineering project, thereby reducing the impact of shock waves on the underground engineering project when the surrounding rock of the underground engineering project is subjected to severe explosions such as ground drilling explosions. After fracture, the surrounding rock of the underground engineering project will produce multiple layers of fracture surfaces, which can significantly reduce the propagation intensity of the explosive load, thereby forming a safe protection for the underground engineering project. When performing explosive fracture, it is necessary to produce a suitable fracture range through the minimum explosive load. Therefore, a special fracture device 1 is required for fracture. The fracture device 1 includes a conduit 3 extending in a vertical direction and a plurality of fracture disks 2 distributed in a vertical direction on the conduit. The conduit 3 is connected to the center position of each fracture disk 2. The conduit 3 located at the center position enables the plurality of fracture disks 2 to evenly perform explosive fracture on the surrounding rock after detonation, thereby achieving a better fracture effect. In addition, the structure of the fracture disk is specifically described by taking a fracture disk as an example. Please refer to Figure 1-Figure 3The chamber inside the fracturing disk 2 includes an explosive chamber 4 and a detonator chamber 5. The explosive chamber 4 is an annular structure chamber arranged on the outer periphery of the disc-shaped fracturing disk. The annular structure of the explosive chamber structure can realize the uniform arrangement of the explosives inside the fracturing device, and the explosives located at the outer edge are more conducive to fracturing the surrounding rock during the explosion, which is safer and more convenient in the arrangement and use of the fracturing device 1; the detonator chamber 5 is an annular structure chamber arranged between the explosive chamber 4 and the conduit 3, and the detonator chamber 5 and the explosive chamber 4 are interconnected; a first detonating cord 601 extending in the vertical direction is arranged through the chamber of the conduit 3, and a charge is buried in the explosive chamber 4. A second detonating cord 602 is provided in a ring shape, and detonators are arranged in the detonator chamber 5. The detonating joints of the second detonating cord 602 and the detonating joints of the detonators are both connected to the first detonating cord 601. With the help of the double safety design of the second detonating cord 602 and the detonator, the explosives in the explosive chamber 4 are guaranteed to be detonated and duds are avoided. At the same time, the ring-shaped second detonating cord 602 can simultaneously detonate the explosives in the explosive chamber 4, thereby realizing the fracturing process of the cracker 1. At the same time, the first detonating cord 601 extending from the guide tube 3 realizes remote control of the explosion process of the cracker 1, which is conducive to the synchronous detonation of multiple crackers 1. In order to further optimize the structure of the fracturing disk 2, the middle part of the outer wall surface of the fracturing disk (i.e., the outer arc surface extending in the circumferential direction) is recessed toward the direction of the guide tube 3 so that the outer wall surface of the fracturing disk is arranged in a "V" shape. This structure enables the explosives to more concentratedly impact the surrounding rock at the "V"-shaped notch position during explosion, thereby increasing the strength of the broken surrounding rock. The explosives can effectively expand the fracturing range and save the use of explosives. In addition, the thickness of the explosive chamber 4 in the vertical direction is greater than the thickness of the detonator chamber 5 in the vertical direction, so that the central area of ​​the fracturing disk 2 is concave compared to the outer edge area, which can further expand the fracturing range.

[0049] Several fracturing devices 1 are buried within the protection zone of an underground project, with fracturing disks 2 at the same level located on the same horizontal plane. The fracturing disks at the multiple levels are further divided into multiple vertical segments. After the fracturing devices are segmented, a vibration velocity sensor 10 for sensing the intensity of the explosion shock is installed on the inner wall of the mounting hole for the fracturing devices, which is located in the immediate fracturing zone. The segmented fracturing disks 2 are detonated in sections based on the explosion shock intensity sensed by the vibration velocity sensor 10. This not only provides fracturing protection for the underground project, but also avoids unnecessary damage to the surrounding rock formations caused by the detonation of too many fracturing disks when the underground project is subjected to a less severe explosion.

[0050] Reference Figure 5 、 Figure 6As an embodiment of the present invention, when this method is used for fracturing, for the protection of large-scale underground projects deep underground, the fracturing device 1 can be selected as a multi-layer equidistant structure fracturing device. Each conduit 3 of the multi-layer equidistant structure fracturing device 1 is provided with a plurality of fracturing disks 2, and the plurality of fracturing disks 2 are evenly spaced on the conduit 3. The multiple fracturing disks 2 evenly spaced on the conduit 3 can be explosively fractured simultaneously or in sections, which can achieve stable fracturing while expanding the fracturing range of the fracturing device 1, and can be used for uniform multi-layer fracturing of the surrounding rock of the underground project 9, forming multiple layers of equally spaced radial fracture surfaces 8. The multi-layer equidistant structure fracturing device 1 includes the fracturing disks 2 and Figure 1-Figure 3 The rupture disks of the single-layer rupture devices shown are the same and their structures will not be repeated.

[0051] The multiple rupture disks 2, evenly spaced on the guide tube 3, completely correspond vertically (i.e., the projections of the multiple rupture disks on the same guide tube 3 on the horizontal plane overlap). The guide tube 3 passes through the center of the multiple rupture disks 2, and the detonating connector of the detonator and the detonating connector of the second detonating cord 602 in each rupture disk 2 are connected to the first detonating cord 601 inside the guide tube. For a multi-layer, equidistant-structured rupture device 1, the distance between two adjacent layers of rupture disks 2 can be calculated based on the hardness of the surrounding rock to be fractured and the size of the explosive chamber above the rupture disk. The number of rupture disks installed in a multi-layer, equidistant-structured rupture device can be determined based on the range of surrounding rock to be protected above the underground project and the importance of the actual underground project. During this determination process, the number and spacing of rupture disks on the same rupture device can be adjusted according to the burial depth and the level of defense requirements. The principle is that when the defense requirements are high, the number of rupture layers is large and the interlayer spacing is small, while when the defense requirements are low, the number of rupture layers is small and the interlayer spacing is large. Multi-layer fracturing with equal spacing forms equidistant and uniform layered fragmentation and cracks. The construction technology is simple, and it is only necessary to grasp the equidistant distribution of the fracturing disks. After the layered fragmentation and cracks are formed, they can block the transmitted explosion stress waves many times, reducing the explosion stress level that finally reaches the protected body.

[0052] For example, in an underground project 9 for personnel refuge and important equipment work sites that is about 30 meters above the ground, 6 meters wide, 9 meters long, and has a horizontal projection area of ​​54 square meters, the protection level requirement is relatively high. In this embodiment, 45 multi-layer equidistant structured crackers are selected for protection. Each multi-layer equidistant structured cracker is provided with 6 layers of cracking disks distributed in the vertical direction. The horizontal projections of the aforementioned 45 crackers follow the plum blossom arrangement principle. Specifically, the projections of the aforementioned 45 crackers on the horizontal plane are arranged in multiple rows, and the crackers in adjacent rows are staggered (e.g., Figure 10 As shown in Figure 2), the rupture disks of the same level on the rupture devices with different multi-layer equidistant structures are located on the same horizontal plane (as shown in Figure 2). Figure 9 、 Figure 12As shown, the spacing between two adjacent multi-layer equidistant crackers in the same row can be set to 4 meters, and the spacing between two adjacent rows of multi-layer equidistant crackers can be set to 3.46 meters. The spacing between two adjacent layers of crack disks 2 on the same cracker 1 is 2 meters, forming a six-layer cracking plane with a horizontal coverage area of ​​approximately 600 square meters. When using this data to protect underground projects 9 for personnel refuges and important equipment work areas, it is possible to quickly deploy multi-layer cracking planes 8 that fully cover the underground project, effectively blocking the propagation of explosion stress waves and reducing the risk of damage to the project. When performing a segmented explosion, the six layers of crack disks 2 can be divided into two sections: the three layers of crack disks located vertically on the upper side serve as the first cracking disk, and the remaining three layers of crack disks located vertically on the lower side serve as the second cracking disk. A threshold for the explosion of the second cracking disk is pre-set. After the explosion of the first cracking disk, the detonation of the second cracking disk is determined based on whether the explosion impact intensity sensed by the vibration velocity sensor reaches the aforementioned explosion threshold.

[0053] The process of using the above-mentioned fracturing device to protect underground engineering and dividing a plurality of fracturing disks 2 into sections and fracturing the surrounding rock of the underground engineering by batch explosion of different sections is as follows:

[0054] Reference Figure 4 、 Figure 5 、 Figure 9 First, the dimensions of the fracturing disk 2 on the fracturing device 1 and the locations of the mounting holes 7 for several anti-explosion protection structures are calculated based on the protected area. The specific process is as follows: The coverage of the fracture surface 8 of the rock mass after the fracturing disk 2 is blasted is determined. After ensuring a relatively economical combination of drilling construction and fracturing disk 2 charge, the drilling dimensions, as well as the size and charge of the fracturing disk 2, are determined through blasting and fracturing tests. The distance between adjacent mounting holes 7 is determined by the coverage of the fracture surface 8 of the rock mass after the fracturing disk 2 is blasted. Ultimately, the optimal drilling plan and fracturing disk 2 dimensions are determined while meeting technical requirements. Drilling is then performed based on the previously calculated locations and depths of the mounting holes 7. The drilling depth must be precise to ensure that the fracturing disks 2 at the same level on the fracturing device 1 are aligned in the same plane.

[0055] Reference Figure 10 、 Figure 11A fracturing device 1 is installed in the mounting hole 7 and arranged in sections. The layers of fracturing disks 2 on each fracturing device 1 are divided into at least two sections. The first fracturing disk located at the top in the vertical direction is used to form a permanent fracturing zone in the upper layer after explosion, and the remaining fracturing disks are used to form an immediate fracturing zone in the lower layer after explosion. The principle of hole arrangement and placement of the fracturing devices is to ensure that the fracturing range of each layer in the vertical direction of the rock mass can be covered and the fracture plane is formed to penetrate. After the fracturing devices are installed, the fracturing devices are observed in the vertical direction. Several rows of fracturing devices are arranged, and adjacent rows of fracturing devices are staggered to form a plum blossom arrangement. This will form even-numbered rows of fracturing devices and odd-numbered rows of fracturing devices. This staggered arrangement can reduce the overlapping area of ​​the fracture surfaces of two adjacent fracturing devices during the fracturing process, thereby increasing the fracture surface.

[0056] Reference Figure 13 After the rupture disks are segmented and installed, vibration velocity sensors are deployed. The number of vibration velocity sensors to be deployed within the protected engineering site is determined based on the scope of the protected object. The vibration velocity sensors are evenly distributed, with several sensors located on the inner walls of the mounting holes corresponding to each rupture disk segment in the immediate rupture zone. Ensure that at least one vibration velocity sensor is located on the inner wall of the mounting hole corresponding to the topmost rupture disk in each rupture disk segment in the immediate rupture zone, and that the spacing and maximum row spacing of the vibration velocity sensors are less than or equal to the minimum planar dimensions of the protected object. When deploying the vibration velocity sensors, a threshold is set to trigger the segmented explosion of the rupture disks in the immediate rupture zone. When the sensors sense that the explosion shock wave reaches the explosion threshold, they are used to trigger the segmented explosion and rupture of the corresponding rupture disks.

[0057] Reference Figure 10 、 Figure 12 To minimize the propagation intensity of the explosive stress wave during the initial explosion, after the fracturing device is deployed, the first fracturing disk 2 of the fracturing device 1 can be explosively fractured, depending on the importance of the protected object and the potential explosion depth, to form a fracture plane 8 in the upper rock mass. During the explosion, the first detonating cord 601 in the conduit 3 directly ignites the first detonator and the second detonating cord 602, thereby detonating the explosives in the explosive chamber and forming a permanent fracture plane 8.

[0058] Reference Figure 13 、 Figure 14After the fracture surface of the upper rock mass is formed, secondary mounting holes 701 are drilled in a uniformly distributed manner between the several mounting holes 7 for mounting the fracturing device 1. The secondary mounting holes 701 and the mounting holes 7 on the same row are staggered, and the drilling depth of the secondary mounting holes 701 is set according to the distance from the ground surface to the midpoints of the two lowest fracturing disks in the first stage. When explosives are loaded into the secondary mounting holes 701 set at the aforementioned positions, it can be ensured that the rock mass broken by the secondary explosion is within the range of the fracture surface formed by the first fracturing.

[0059] After drilling is completed, the explosives are loaded in small intervals according to the rock properties of the project site, and the center of the charge is ensured to be located in the middle of the rock fracture layer. The center of the charge corresponds to the center of the fracture surface caused by the first explosion to achieve a better and more uniform fracture effect.

[0060] Reference Figure 15 Then, the explosives in the secondary installation hole 701 are subjected to secondary blasting to form a rock fracture zone between the fracture layers. The rock fracture formed by the secondary blasting produces more gap spaces and forms more broken blocks, which can better resist the explosion impact and projectile penetration.

[0061] Finally, grouting is performed through the secondary installation holes 701 into the fractured fracture surfaces 11 formed by the secondary fracturing. During grouting, polyurea grouting can be performed based on the location of each secondary installation hole 701, filling the fracture surfaces 8 and the fractured rock mass between them with polyurea slurry. Because polyurea has excellent resistance to blast and impact, it forms an effective blast-resistant layer after hardening. In addition to effectively reflecting the blast stress wave through the discontinuous interface formed by the rock mass fractures and the polyurea layer, the polyurea layer also effectively resists rock mass deformation, further enhancing the rock mass's resistance to blast and penetration. This creates a highly effective upper fracture zone, which serves as a permanent fracture zone.

[0062] After the permanent fracture zone is formed, if the rock mass at that location is struck and explodes, while the permanent fracture zone can effectively reduce the propagation of the blast stress wave, with the advancement of explosive performance and weapon systems, the propagation intensity of the blast stress wave is difficult to predict. To maintain sufficient protection and safety reserves, the next stage of fracture disk 2 is explosively fractured when the blast shock intensity sensed by the pre-set vibration velocity sensor 10 reaches the lower explosion threshold, forming more rock fracture surfaces along the blast stress wave propagation path, thereby blocking the propagation of stress waves and achieving the purpose of effectively protecting underground engineering. For example, in a multi-layer equidistant fracture device, the 4-meter-thick surrounding rock between the three upper fracture disks is the permanent fracture zone, while the surrounding rock between the remaining three lower fracture disks is the immediate fracture zone. After the three layers of fracture disks are detonated and the permanent fracture surfaces are formed, secondary mounting holes 701 are drilled. 45 secondary mounting holes are provided, and the secondary mounting holes in each row are staggered with the fracture device. The drilling depth of secondary installation hole 701 is set to the distance from the ground surface to the midpoint of the lowest of the first three detonated fracturing disks (i.e., 5 meters). During charging, small explosive charges designed to break the rock between the fracturing planes are placed and detonated at the 5-meter and 3-meter positions, based on the site's rock mass hardness and reasonable unit consumption, to achieve interlayer rock fragmentation. Finally, polyurea grouting is performed through secondary installation hole 701 into the secondary fracturing zone, filling the 4-meter-thick rock mass between the first three fracturing disks with polyurea slurry. Once hardened, this grout forms an effective polyurea anti-blast layer. Besides effectively reflecting the blast stress wave at the discontinuous interface between the rock fractures and the polyurea layer, the polyurea layer also effectively resists rock deformation, further strengthening the rock's resistance to blast and penetration. This creates a permanent fracturing zone. After the permanent fracture zone is formed, the three-layer fracture disk at the bottom is divided into one section. This section of the fracture disk is detonated when the vibration velocity sensor 10 embedded in the mounting hole reaches the set threshold, forming a fracture surface of the instant fracture zone.

[0063] Reference Figure 7 、 Figure 8 As a second embodiment of the present invention, a multi-layer proportional distance structure of a rupture device 1 can also be used. The rupture device has a plurality of rupture discs 2 provided on a catheter 3, and the distance between two adjacent layers of rupture discs 2 is distributed according to a proportional distance. Specifically, five rupture discs 2 are provided on the same catheter 3. From top to bottom, the five rupture discs are sequentially referred to as the first rupture disc, the second rupture disc, the third rupture disc, the fourth rupture disc, and the fifth rupture disc. Assume that the distance between the second rupture disc and the first rupture disc is Δ h 1 , then the distance between the third rupture disk and the second rupture disk is Δ h 2 = Δ h 1 n, the distance between the fourth rupture disk and the third rupture disk is Δ h 3 = Δ h 2 n , the distance between the fifth rupture disk and the fourth rupture disk is Δ h 4 = Δ h 3 n , and the multiple rupture disks 2 distributed at proportional distances on the same catheter are the same as the rupture disks 2 included in the single-layer structure rupture device, and their structures will not be repeated.

[0064] The spacing of the two fracturing disks is distributed in a proportional distance, which can be used for multi-layer fracturing of the surrounding rock of underground projects in a proportional distance distribution, forming a multi-layer radial fracture surface distributed in a proportional distance. The number of fracturing disks and the spacing of the fracturing disks of the multi-layer proportional distance structure can be set according to the importance of the actual project. Before setting, it is necessary to conduct a test on the attenuation law of the blasting vibration velocity of the protection site. After obtaining the attenuation coefficient α of the site, it can be used as the distance index for the proportional spacing setting. n The number of fracturing disks provided on a multi-layer proportional distance structure fracturing device 1 can be determined based on the range of surrounding rock that needs to be protected above the underground project 9 and the importance of the actual project. During the determination process, the number and spacing of the fracturing disks 2 on the same fracturing device 1 can be adjusted according to the burial depth and the level of defense requirements. The principle is that when the defense requirements are high, the number of fracturing layers is large and the inter-layer spacing is small, while when the defense requirements are low, the number of fracturing layers is small and the inter-layer spacing is large.

[0065] Multi-layer fracturing with proportional distance spacing can more accurately set the spacing between fracturing disks according to the vibration attenuation law of the site. Multi-layer fracturing with relative spacing can effectively reduce the number of fracturing disks to achieve the same shock absorption effect. The precise and efficient layout can fully cover the multi-layer fracture surface of the underground project, effectively block the propagation of explosion stress waves, and reduce the risk of project damage.

[0066] For example, in an underground important facility and personnel protection project about 60 meters above the ground, 4.2 meters wide, 6 meters long, and with a horizontal projection area of ​​25.2 square meters, the protection level is relatively high. When fracturing, 45 multi-layer proportional distance structure fracturers are set for protection. Each multi-layer proportional distance structure fracturer is equipped with 6 layers of fracturing disks. According to the blasting attenuation index of 1.6 for medium-hard rock engineering sites, it can be calculated that: if the distance Δ between the second fracturing disk and the first fracturing disk is h 1 is 1.5 meters, then the distance between the third rupture disk and the second rupture disk is Δ h 2 =1.5 1.6 = 1.91 m, the distance between the fourth and third rupture disks is Δ h 3 = 1.91 1.6 = 2.82 m, the distance between the fifth and fourth rupture disks is Δh 4 = 2.82 1.6 = 5.26 m, the distance between the sixth and fifth rupture disks Δ h 5 = 5.26 1.6 = 14.24 meters. When the first layer of rupture disks is 2 meters below the ground surface, the sixth rupture disk is buried at a depth of 27.73 meters. When rupture disks are arranged at 2-meter intervals, 12 rupture disks are required on the same conduit. When rupture disks are arranged at proportional intervals, the number is reduced to 6. This significantly reduces the number of rupture disks required and allows for more precise attenuation of blast stress waves based on project site conditions. The horizontal projection of the 45 rupture disks follows a quincunx arrangement principle. Specifically, the 45 rupture disks are arranged in multiple rows, with adjacent rows of rupture disks staggered. Furthermore, rupture disks on the same level of rupture disks in different multi-layer equidistant structures are located on the same horizontal plane. The spacing between adjacent multi-layer proportional interval rupture disks in the same row can be set at 3 meters, and the spacing between adjacent multi-layer proportional interval rupture disks in the same row can be set at 2.6 meters. With six rupture disks, a six-layer rupture plane is formed, covering an area of ​​approximately 273 square meters. When using the above data to protect underground projects where personnel are taking shelter or where important equipment is working, multiple layers of fracture surfaces 8 can be quickly deployed to fully cover the underground project, effectively blocking the propagation of explosion stress waves and reducing the risk of project damage. When performing a segmented explosion, the six layers of fracture disks 2 can be divided into two sections: the three layers of fracture disks located vertically on the upper side serve as the first segment of fracture disks, and the remaining three layers of fracture disks located vertically on the lower side serve as the second segment of fracture disks. After the explosion of the first segment of fracture disks, the vibration detected by the vibration velocity sensor 10 is determined to determine whether the vibration reaches the threshold for the explosion of the second segment of fracture disks, thereby determining whether to detonate the second set of fracture disks.

[0067] The specific process of using the above-mentioned fracturing device to protect underground projects and dividing several fracturing disks into sections and fracturing the surrounding rock of underground projects through batch explosions of different sections is the same as the process of the fracturing device with multi-layer equidistant and equal spacing structure, and will not be repeated.

[0068] As another embodiment of the present application, multiple bursts of explosive fracturing can be performed sequentially in the immediate fracturing zone, following the aforementioned fracturing steps, in conjunction with the blast shock intensity sensed by the vibration velocity sensor, until the blast shock no longer damages the underground structure. This method of sequentially monitoring and performing batches of explosive fracturing can achieve better resistance to blast shock, while minimizing damage to the surrounding rock mass of the building while safely protecting the underground structure.

[0069] For example, refer to Figure 15 , the number of rupture disks on each fracturing device 1 can be set to 6, the three rupture disks located at the uppermost side in the vertical direction are the first section, the fourth rupture disk is the second section, the fifth rupture disk is the third end, and the sixth rupture disk is the fourth section. The process of forming a permanent rupture zone by the first rupture disk is the same as above. After the permanent rupture zone is formed, the bottom can be divided into 3 sections for rupture, and a vibration velocity sensor 10 is arranged at the positions corresponding to the fourth rupture disk, the fifth rupture disk, and the sixth rupture disk on the inner wall of the mounting hole. The triggering condition for the second to fourth rupture disks to detonate and form a new fracture surface is that the vibration velocity sensor buried in the hole reaches different set thresholds. These threshold values ​​are determined in accordance with the "Blasting Safety Regulations" or according to the actual defense vibration velocity requirements. For example, the maximum vibration velocity allowed in the power generation center control room according to the "Blasting Safety Regulations" is 15 cm / s.

[0070] Reference Figure 16 Each fracturing device 1 may be provided with 12 rupture disks, with three rupture disks forming a segment in the vertical direction. The process for forming a permanent rupture zone in the first rupture disk located at the uppermost vertical position is the same as above. After the permanent rupture zone is formed, the bottom portion may be further divided into three segments for rupture. A vibration velocity sensor 10 is disposed on the inner wall of the mounting hole at positions corresponding to the uppermost rupture disk of the second segment (i.e., the fourth rupture disk), the uppermost rupture disk of the third segment (i.e., the seventh rupture disk), and the uppermost rupture disk of the fourth segment (i.e., the tenth rupture disk), respectively. The triggering condition for the detonation of the second to fourth rupture disks to form a new fracture surface 8 is that the vibration velocity sensor 10 embedded in the hole reaches different set thresholds. These threshold values ​​are determined in accordance with the "Explosive Safety Regulations" or based on actual design vibration velocity requirements. For example, the maximum vibration velocity allowed in the control room of a power generation center as specified in the "Explosive Safety Regulations" is 15 cm / s.

[0071] The above is only a preferred embodiment of the present invention. Any simple modification, equivalent change and modification made to the above embodiment by any technician familiar with this profession based on the technical essence of the present invention without departing from the scope of the technical solution of the present invention shall still fall within the scope of the technical solution of the present invention.

Claims

1. A method for protecting underground engineering from blasting by strengthening self-fragmentation of rock mass, characterized by: The steps of this protection method are as follows: S1: Calculate the size of the rupture disk on the rupture device and the locations of the mounting holes of several anti-explosion protection structures according to the protection area; S2: After determining the depth of the mounting holes, drilling is performed. The projections of the mounting holes for mounting the crackers on the horizontal plane are arranged in multiple rows, and the mounting holes in two adjacent rows are staggered. S3: Installing a fracturing device in the mounting hole and arranging the plurality of fracturing disks on the fracturing device in sections, wherein the first fracturing disk located at the uppermost side in the vertical direction is used to form a permanent fracturing zone, and the remaining fracturing disks are used to form immediate fracturing zones; S4: Deploying a vibration velocity sensor on the inner wall of a mounting hole corresponding to each rupture disk in the immediate rupture zone, and setting a threshold for triggering rupture disk explosion for the vibration velocity sensor; S5: Explosively fracture the first fracture disk on the fracture device to obtain a permanent fracture zone; S6: When the explosion impact intensity sensed by the corresponding vibration velocity sensor reaches the set explosion threshold, the remaining vertically distributed fracturing disks are sequentially subjected to segmented explosive fracturing to form deeper instant fracturing zones until the explosion impact no longer causes damage to the underground engineering. The fracturing device described in the aforementioned steps includes a plurality of fracturing disks distributed at equal or proportional distances and a conduit extending in a vertical direction. The conduit is connected to the center of the plurality of fracturing disks. An explosive chamber for placing explosives is provided in the fracturing disks. A first detonating cord for igniting the explosives in the explosive chamber is provided in the conduit. Fracturing disks at the same level on different fracturing devices are located in the same horizontal plane.

2. The method for protecting underground engineering from blasting by reinforced rock self-fragmentation according to claim 1, characterized in that: After the first rupture disk in S5 explodes, a secondary rupture is set up to be broken by explosives. The specific process of the secondary rupture is as follows: S51: After the first stage of the cracker explosion is completed, secondary mounting holes are drilled at positions staggered with the plurality of mounting holes on each row; S52: Install explosives in the secondary installation hole; S53: Perform secondary blasting to break up the rock mass between the fissure layers; S54: Grouting is performed on the broken crack surface formed by the second cracking through the secondary installation hole.

3. The method for protecting underground engineering from blasting by reinforced self-fragmentation of rock mass according to claim 1, characterized in that: The distance between adjacent mounting holes in S1 is determined by the coverage of the rock mass fracture surface after the fracturing disk is blasted.

4. The method for protecting underground engineering from blasting by reinforced self-fragmentation of rock mass according to claim 1, characterized in that: The vibration velocity sensor in S4 is arranged in the immediate fracturing zone and on the inner wall of the mounting hole corresponding to the uppermost fracturing disk in each fracturing disk in the horizontal direction, and the maximum value of the spacing and row spacing of the vibration velocity sensors is less than or equal to the minimum size of the protected underground project on the plane.

5. The method for protecting underground engineering from blasting by reinforced self-fragmentation of rock mass according to claim 2, characterized in that: The drilling depth of the secondary installation hole in S51 is from the ground surface to the midpoint of the two lowest rupture disks in the first stage of rupture disks.

6. The method for protecting underground engineering from blasting by reinforced self-fragmentation of rock mass according to claim 2, characterized in that: In the S52, the explosive charging is completed in a small amount interval charging manner.

7. The method for protecting underground engineering from blasting by reinforced self-fragmentation of rock mass according to claim 2, characterized in that: In the S54, polyurea slurry is used for grouting.

8. The method for protecting underground engineering from blasting by reinforced self-fragmentation of rock mass according to claim 1, characterized in that: The chamber inside the rupture disk includes an annular explosive chamber arranged on the periphery of the rupture disk and used to bury explosives, and an annular detonator chamber arranged between the explosive chamber and the guide tube and used to lay detonators. The explosive chamber and the detonator chamber are in a connected state. An annular second detonating cord is arranged in the explosive chamber, and the detonating joint of the detonator and the detonating joint of the second detonating cord are both connected to the first detonating cord.

9. The method for protecting underground engineering from blasting by reinforced self-fragmentation of rock mass according to claim 1, characterized in that: Several rupture disks on the same catheter completely correspond to each other in the vertical direction.

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