Active prevention and control method for deep tunnel fracture type rockburst inoculation process

Abstract

The invention provides an active prevention and control method for a fracture type rockburst inoculation process of a deep tunnel, and belongs to the technical field of deep tunnel rockburst prevention and control. Before the fracture is revealed, judging whether the fracture is distributed in front of the tunnel face, the fracture occurrence, the mileage intersected with the tunnel top arch and the direction of the tunnel crossing the fracture; in the tension fracture initiation stage, according to the accumulated apparent volume sudden increase rate of adjacent micro-seismic events, the implementation time of measures for reducing tunnel surrounding rock stress concentration is determined, and the generation of tension fracture is inhibited; in the fracture expansion stage, the opportunity of applying a stress release hole to the fracture is determined according to the K value growth rate, and closed stress near the fracture is released; in the fracture accumulation-fracture slippage stage, an anti-shearing anchor rod is applied to the fracture, and fracture penetration and fracture slippage are restrained; and after the tunnel surrounding rock and the fracture are locked and fixed and before the fracture of the tunnel face is exposed, corresponding measures are taken according to the fracture type rockburst risk level until the tunnel face safely passes through the fracture. The number of used arch frames is reduced while the engineering safety is guaranteed, and the economic cost is reduced.

Description

Technical Field

[0001] The present invention relates to the technical field of rockburst prevention and control in deep-buried tunnels, and in particular to a method for actively preventing and controlling a fracture-type rockburst incubation process in a deep-buried tunnel. Background Art

[0002] During the excavation of deep buried tunnels, fault structures or large structural surfaces are often crossed, resulting in fracture-type rockbursts. Fault-type rockbursts have a large impact area and strong destructive power, and may even induce continuous strong or extremely strong rockbursts, causing sudden accidents, equipment damage, serious delays in construction schedules and other serious consequences. Carrying out safe and economic prevention and control of fracture-type rockbursts is crucial to ensure the safe construction of deep buried tunnels.

[0003] At present, the main means of rockburst prevention and control include stress release, anchor support and other technologies. For example, the patent "Rockburst active prevention and control system", patent number "CN202310498496.9"; the patent "A deep buried tunnel instant rockburst active prevention and control method", patent number "CN201810031286.8"; the patent "A prevention and control structure for rockburst tunnels", patent number "CN202310498734.6"; the patent "Rockburst control and design method", patent number "CN202310494561.0". These inventions distinguish the rockburst levels and use stress release, anchor support and other technologies. (Anchor cable) support and other technologies are used to prevent and control rockbursts, which have achieved results in the prevention and control of high-stress-dominated rockbursts such as strain-type rockbursts. However, for fracture-type rockbursts, if their incubation process cannot be curbed in advance before excavation and exposure, it is difficult to effectively prevent the occurrence of fracture-type rockbursts by relying solely on strong support measures after excavation and exposure, or only on stress release and conventional system support measures in high-stress areas. Even after excavation and exposure, fracture-type rockbursts have already occurred and strong support cannot be carried out in time, resulting in serious consequences such as sudden accidents, equipment damage, and construction delays.

[0004] Therefore, a method for actively controlling the incubation process of tunnel fracture-type rockburst is needed. Summary of the invention

[0005] In view of this, the present invention provides an active prevention and control method for the incubation process of fracture-type rockburst in deep-buried tunnels. The method identifies the fracture state and position in advance based on microseismic information, and implements stress release and support measures in advance according to the fracture state, position and incubation process. The method pre-releases the surrounding rock stress and the closed stress near the fracture, reduces the degree of rupture of the surrounding rock and the area near the fracture, further locks the fracture, reduces the risk of fracture initiation, and achieves the purpose of controlling the incubation process of fracture-type rockburst.

[0006] To this end, the present invention provides the following technical solutions:

[0007] An active prevention and control method for a fracture-type rockburst incubation process in a deep-buried tunnel, comprising:

[0008] The microseismic monitoring system arranged behind the tunnel face monitors the microseismic event information during the excavation process in real time. Before the fracture is exposed, the microseismic event information is used to determine whether there is a fracture in front of the tunnel face, the fracture occurrence, the mileage of the intersection with the tunnel crown arch, and the direction of the tunnel crossing the fracture.

[0009] Determine the fault-type rockburst grade and fault-type rockburst incubation stage through microseismic event information;

[0010] Dynamically adjust the fracture-type rockburst prevention and control measures according to the fracture-type rockburst risk level, fracture-type rockburst incubation stage, and the direction of the tunnel crossing the fracture:

[0011] At the rupture initiation stage, the timing of taking measures to reduce the stress concentration of the tunnel surrounding rock is determined according to the cumulative apparent volume sudden increase rate of adjacent microseismic events to inhibit the occurrence of tensile rupture.

[0012] In the fracture propagation stage, the timing of arranging stress release holes is selected according to the growth rate of K value to release the closed stress near the fracture;

[0013] In the fracture accumulation-fracture slip stage, according to the distance between the tunnel face and the fracture, shear anchors or cables are installed to lock the tunnel surrounding rock and the fracture, thus preventing fracture penetration and fracture slip;

[0014] After the tunnel surrounding rock and the fracture are locked and before the fracture is exposed at the face, appropriate measures are taken according to the fracture-type rock burst risk level until the face passes through the fracture.

[0015] Furthermore, the microseismic event information includes:

[0016] The number of microseismic events, the energy released by microseismic events, and the three-dimensional coordinates of rock fracture events in space.

[0017] Furthermore, before the fault is revealed, it is determined based on the microseismic event information whether there is a fault in front of the tunnel face, the occurrence of the fault, the mileage of the fault intersecting the tunnel arch, and the direction of the tunnel crossing the fault, including:

[0018] According to the three-dimensional coordinates of the rock failure event in space and the microseismic release energy, the interpolation method is used to draw the distribution cloud map of the rock failure event space and microseismic release energy in front of the tunnel face;

[0019] When the rock fracture event space and the microseismic release energy distribution cloud map have linear or strip distribution characteristics, it is determined that there is a fracture in front of the tunnel face, and the extreme value points are connected into a line to represent the fracture and obtain the spatial information of the fracture;

[0020] Based on the spatial information of the fault, determine the fault occurrence, the mileage of the intersection with the tunnel crown, and the direction of the tunnel crossing the fault;

[0021] The direction in which the tunnel crosses the fault includes tunneling from the upper wall of the fault to the lower wall and tunneling from the lower wall of the fault to the upper wall.

[0022] Furthermore, the fracture type rock burst level includes:

[0023] There are non-fracture type rockburst, slight fracture type rockburst, moderate fracture type rockburst, strong fracture type rockburst and extremely strong fracture type rockburst.

[0024] Furthermore, the method of determining the incubation stage of fracture-type rockburst by using microseismic event information includes:

[0025] When the number of daily accumulated microseismic events is less than 20 and all of them are tensile ruptures with release energy less than 1000 J, it is judged to be the rupture initiation stage;

[0026] When the daily cumulative number of microseismic events is 20 to 40, and contains more than three rupture events with release energy higher than 1000 J, it is judged to be the rupture extension stage;

[0027] When the cumulative number of microseismic events per day is greater than 40 and contains more than one shear rupture event with a release energy greater than 10,000 J, it is judged to be the rupture accumulation-fault slip stage.

[0028] Furthermore, in the rupture initiation stage, according to the cumulative apparent volume sudden increase rate of adjacent microseismic events, the timing of taking measures to reduce the stress concentration of the tunnel surrounding rock is determined to suppress the occurrence of tension rupture, including:

[0029] When it is determined to be a medium-fracture rockburst and the cumulative apparent volume increase rate of adjacent microseismic events is greater than 45%, the excavation rate is reduced;

[0030] When it is determined to be a strong fracture type rockburst or an extremely strong fracture type rockburst, and the value of the cumulative apparent volume increase rate of adjacent microseismic events is greater than 45%, the excavation rate is reduced and radial stress relief holes are set vertically on the surrounding rock surface;

[0031] The depth of the stress release hole exceeds the depth of the microseismic event concentration area.

[0032] Furthermore, in the fracture propagation stage, the timing of arranging stress release holes is selected according to the K value growth rate to release the closed stress near the fracture, including:

[0033] When the direction of the tunnel crossing the fault is that the tunnel is excavated from the upper wall of the fault to the lower wall, and the K value growth rate is greater than 15%, a stress relief hole is arranged on the upper wall of the fault, and the hole depth of the stress relief hole exceeds the stress concentration zone;

[0034] When the direction of the tunnel crossing the fracture is that the tunnel is excavated from the lower wall of the fracture to the upper wall, and the K value growth rate is greater than 17%, stress relief holes are arranged on the fracture surface, and the hole depth of the stress relief holes exceeds the fracture surface.

[0035] Furthermore, in the fracture accumulation-fracture slip stage, according to the distance between the tunnel face and the fracture, shear anchors or anchor cables are installed to lock the tunnel surrounding rock and the fracture to prevent fracture penetration and fracture slip, including:

[0036] When the direction of the tunnel crossing the fault is from the upper wall to the lower wall, shear anchors or cables are used to pass through the fault surface 0.8 times the tunnel diameter in advance;

[0037] When the direction of the tunnel crossing the fault is from the lower wall of the fault to the upper wall, shear anchors or cables are used to pass through the fault surface in advance of one time the tunnel diameter;

[0038] The intersection angle between the shear anchor rod or anchor cable and the fracture surface is greater than 45°.

[0039] Furthermore, after the tunnel surrounding rock and the fracture are locked and before the fracture is exposed at the tunnel face, corresponding measures are taken according to the fracture type rock burst risk level until the tunnel face passes through the fracture, including:

[0040] When the risk level of fracture-type rockburst drops to medium or below, arch support will not be carried out, and attention will be paid to microseismic activities until the tunnel face passes through the fracture area safely;

[0041] When the risk level of fracture-type rock burst is severe or above, arch support is carried out according to the direction in which the face crosses the fracture.

[0042] Furthermore, the arch support is performed according to the direction in which the tunnel passes through the fracture, including:

[0043] When the tunnel face passes through the fault in the direction of passing through the upper plate of the fault, the arch frame is installed when the distance between the tunnel face and the fault is 0.5 times the tunnel diameter, until the tunnel face passes through 0.8 times the tunnel diameter of the fault;

[0044] When the direction of the tunnel face passing through the fault is that the tunnel face passes through the bottom plate of the fault, when the tunnel face is 0.8 times the tunnel diameter away from the fault, the arch frame is installed until the tunnel face passes through 0.5 times the tunnel diameter of the fault.

[0045] Advantages and positive effects of the present invention:

[0046] (1) The present invention uses microseismic monitoring to identify the occurrence, location and mode of crossing the fault in advance, and releases stress in advance during the process of fracture-type rock burst, thereby reducing the degree of stress concentration, installing shear anchors, and reducing the tendency of rock mass fracture expansion, effectively curbing the incubation of fracture-type rock burst and reducing the risk of rock burst.

[0047] (2) Active prevention and control measures are taken during the incubation of fracture-type rockbursts to reduce the demand and number of rigid support measures such as arches, significantly reducing economic costs and construction risks.

[0048] (3) Continuously monitor the risk of fracture-type rockburst during tunnel excavation through microseismic monitoring, and provide operating parameters and timing for arch support measures to ensure project safety while reducing economic costs. BRIEF DESCRIPTION OF THE DRAWINGS

[0049] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative labor.

[0050] Figure 1 It is a flowchart of the implementation of the fracture type rock burst prevention and control design method in the embodiment of the present invention;

[0051] Figure 2 This is a distribution diagram of rock fracture events in the process of incubation of tunnel fracture type rock burst in an embodiment of the present invention;

[0052] Figure 3 A cloud diagram showing the distribution of microseismic energy released during a rock fracture event in an embodiment of the present invention;

[0053] Figure 4 Schematic diagram of active prevention and control of fracture-type rockburst in the initiation stage of tensile rupture in an embodiment of the present invention;

[0054] Figure 5 Schematic diagram of active prevention and control of fracture-type rockburst in the rupture extension stage in this embodiment; a represents the excavation of the upper plate toward the lower plate, and b represents the excavation of the lower plate toward the upper plate;

[0055] Figure 6 Schematic diagram of active prevention and control of fracture-type rockburst in the fracture accumulation-fracture slip stage in this embodiment; wherein a represents the excavation of the upper plate toward the lower plate, and b represents the excavation of the lower plate toward the upper plate. DETAILED DESCRIPTION

[0056] In order to enable those skilled in the art to better understand the scheme of the present invention, the technical scheme in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work should fall within the scope of protection of the present invention.

[0057] It should be noted that the terms "first", "second", etc. in the specification and claims of the present invention and the above-mentioned drawings are used to distinguish similar objects, and are not necessarily used to describe a specific order or sequence. It should be understood that the data used in this way can be interchanged where appropriate, so that the embodiments of the present invention described herein can be implemented in an order other than those illustrated or described herein. In addition, the terms "including" and "having" and any variations thereof are intended to cover non-exclusive inclusions, for example, a process, method, system, product or device that includes a series of steps or units is not necessarily limited to those steps or units that are clearly listed, but may include other steps or units that are not clearly listed or inherent to these processes, methods, products or devices.

[0058] The present invention provides a method for actively preventing and controlling the fracture-type rockburst incubation process in a deep buried tunnel. Figure 1 As shown, the process mainly includes the following steps.

[0059] S1. A microseismic monitoring system is arranged behind the tunnel face to capture continuous microseismic information during tunnel excavation, identify and obtain rock fracture event information, accurately locate rock fracture events, and calculate microseismic release energy;

[0060] In this embodiment, the location of the rock fracture event includes the three-dimensional coordinates of the event in space;

[0061] S2. Based on the spatial positioning of rock fracture events in S1, the interpolation method is used to draw and analyze in real time the spatial distribution cloud map of rock fracture events and microseismic release energy in front of the tunnel face. At the same time, combined with the rock slag information, it is determined whether there are fractures in front of the tunnel face;

[0062] In this embodiment, if the rock fracture event space and microseismic release energy distribution cloud diagram have linear or strip distribution characteristics, it means that there are fractures in front of the tunnel face and there is a potential risk of fracture-type rock burst;

[0063] When the angle between the fault and the tunnel excavation direction is less than 30°, it is difficult to determine whether there is a fault in front of the face from the rock fracture event space and the microseismic release energy distribution cloud map. At this time, the fault can be exposed earlier, and it can be observed whether the rock slag contains rock blocks with faults to determine the risk of fault-type rock burst.

[0064] S3. According to the spatial distribution of rock fracture events, the distribution cloud map of microseismic energy release and the tunnel excavation information in S2, the fault occurrence, mileage and direction of the tunnel crossing the fault are determined.

[0065] According to the linear or strip distribution characteristics of the rock fracture event space and the microseismic release energy distribution cloud map shown in S2, the extreme points of the cloud map are connected into a line, which is the fault. The fault occurrence, the mileage of the intersection with the tunnel crown arch and the direction of the tunnel crossing the fault are determined.

[0066] In this embodiment, the direction of the tunnel crossing the fault includes tunneling from the upper wall of the fault to the lower wall and from the lower wall of the fault to the upper wall. Because the risk and incubation process of fault-type rock burst are significantly different under different fault crossing directions, it is necessary to distinguish the direction of the tunnel crossing the fault;

[0067] S4. Determine the potential risk level of fault-type rockburst through microseismic activity during the incubation process of fault-type rockburst;

[0068] The risk levels of fracture-type rockburst include no rockburst, slight rockburst, moderate rockburst, severe rockburst and extremely severe rockburst. The present invention is mainly aimed at fracture-type rockbursts with medium and above risk levels.

[0069] S5. According to the distance between the face and the fault and the changes in the stage of the fault-type rockburst incubation process, the direction of the tunnel crossing the fault and the rockburst risk level are taken into consideration, and the prevention and control measures taken for active prevention and control of fault-type rockburst are dynamically adjusted.

[0070] Compared with excavating from the upper wall to the lower wall, rock burst prevention and control measures are taken earlier when excavating from the lower wall to the upper wall. This is because when excavating from the lower wall to the upper wall, fault-type rock bursts begin to develop earlier and the risk of fault-type rock bursts is higher.

[0071] Active prevention and control of fracture-type rockburst can be divided into three stages, and the judgment basis includes:

[0072] The rupture initiation stage is the initial stage of the incubation of fault-type rock burst, which is mainly tensile rupture with energy less than 1000J, and the cumulative number of microseismic events per day is less than 20.

[0073] The rupture propagation stage is the middle stage of the incubation process of fault-type rockburst, during which microseismic events increase rapidly, including a certain number of rupture events with energy higher than 1000 J. The cumulative number of microseismic events per day is between 20 and 40.

[0074] The rupture accumulation-fault slip stage is the final stage of the fault-type rock burst incubation process. Microseismic events increase sharply, including a certain number of shear rupture events with energy higher than 10,000 J. The cumulative number of microseismic events per day is higher than 40.

[0075] S5.1 The first stage is the initiation stage of tensile rupture. In this stage, the main prevention and control measures are to reduce the stress concentration of the tunnel surrounding rock and inhibit the occurrence of tensile rupture. The occurrence of tensile rupture is the cause of crack penetration near the fault. Inhibiting the occurrence of tensile rupture can reduce the possibility of crack penetration. The specific timing of the operation is determined by the cumulative apparent volume increase rate (CAVG) of adjacent microseismic events:

[0076]

[0077] Where: AV cis the microseismic apparent volume of the current microseismic event, AV p is the microseismic apparent volume of the previous microseismic event, AV a is the cumulative apparent volume of microseismic events up to the present time.

[0078] The cumulative apparent volume sudden increase rate of adjacent microseismic events in the process of fault-type rockburst incubation is calculated in real time, and measures are taken when the value is greater than 45%. The cumulative apparent volume sudden increase indicates that the fault begins to be affected by the excavation disturbance.

[0079] For medium fracture type rock burst, the excavation rate is reduced. For strong and extremely strong fracture type rock burst, radial stress release holes are required to be made vertically on the surface of the surrounding rock while reducing the excavation rate. The hole depth exceeds the depth of the microseismic event concentration area to reduce the stress of the surrounding rock and curb the initiation of tensile rupture. In this stage, the stress of the surrounding rock in different excavation directions is not much different, so there is no need to distinguish the excavation direction.

[0080] S5.2 The second stage is the rupture expansion stage. In this stage, the main prevention and control measures are to release the closed stress near the fracture, reduce the superimposed stress, and inhibit the expansion of the rupture near the fracture. The specific application time is determined by the K value growth rate.

[0081]

[0082] Where: K a is the K value at the current moment, K b is the K value at the previous adjacent moment. The K value is the ratio of the cumulative apparent stress to the cumulative dynamic stress drop. The rapid increase in the K value indicates that the fracture is further affected and has a tendency to dislodge.

[0083] The K value growth rate is calculated in real time. When the tunnel is excavated from the upper wall of the fracture to the lower wall, when ΔK is greater than 15%, advance stress release holes are arranged on the upper wall of the fracture, and the hole depth exceeds the stress concentration area. When the tunnel is excavated from the lower wall of the fracture to the upper wall, when ΔK is greater than 17%, advance stress release holes are arranged on the fracture surface, and the hole depth exceeds the fracture surface. For strong and extremely strong fracture-type rock bursts, the number of stress release holes should be appropriately increased.

[0084] S5.3The third stage is the fracture accumulation-fracture slip stage. In this stage, the main prevention and control measures are to lock the surrounding rock and fractures, and to prevent fracture penetration and fracture slip. When the tunnel is excavated from the upper plate of the fracture to the lower plate, shear anchors / anchor cables are used to pass through the fracture surface 0.8 times the tunnel diameter in advance. When the tunnel is excavated from the lower plate of the fracture to the upper plate, shear anchors / anchor cables are used to pass through the fracture surface 1 times the tunnel diameter in advance.

[0085] The shear anchor rod / anchor cable intersects the fracture surface at a maximum angle. Preferably, the angle is greater than 45°. For strong and extremely strong fracture type rock bursts, the number of anchor rods / anchor cables should be appropriately increased.

[0086] S6. When the face is about to reveal a fracture, pay close attention to microseismic activities during the construction process.

[0087] S6.1 If, through the aforementioned active prevention and control measures, microseismic monitoring shows that the risk of fault-type rockburst has dropped to medium or below, other support measures may not be taken temporarily, and attention should be paid to microseismic activities until the face safely passes through the fault area.

[0088] S6.2 If microseismic monitoring shows that there is still a strong or higher risk of fault-type rockburst, arch support is required. When the tunnel face passes through the upper plate of the fault, the arch support is installed when the tunnel face is 0.5 times the tunnel diameter of the fault, until the tunnel face passes through 0.8 times the tunnel diameter of the fault; when the tunnel face passes through the lower plate of the fault, the arch support is installed when the tunnel face is 0.8 times the tunnel diameter of the fault, until the tunnel face passes through 0.5 times the tunnel diameter of the fault.

[0089] The method of the present invention is further described with specific application examples:

[0090] This example is a deep buried TBM granite tunnel with a diameter of 7m. The lithology of the tunnel is mainly Variscan granite intercalated with biotite granite. The rock quality is hard, and the rock mass is intact and stable. On June 25, 2021, the tunnel face was excavated to a certain mileage. It was found that the microseismic events and microseismic release energy distribution cloud map in front of the face showed a significant strip distribution, such as Figure 2 , Figure 3 As shown in the figure, 1. rock fracture event; 2. tunnel; 3. fracture; 4. strip distribution area of ​​rock fracture event. It is determined that there are fractures in front of the tunnel face, with potential strong fracture-type rock burst risk, and the tunnel face passes through the upper plate of the fracture.

[0091] In this embodiment, the risk level of fracture-type rockburst is predicted by using the collected microseismic event information through a deep convolutional neural network model.

[0092] At the initiation stage of tension rupture: At 16:32 on June 25, 2021, microseismic monitoring showed that CAVG>45%. Energy reduction measures were adopted on site to reduce the TBM excavation rate, and the excavation rate was reduced from 3.47m / 4h to 1.45m / 4h. At the same time, surrounding rock stress release holes were constructed. Based on the spatial distribution characteristics of microseismic events, radial stress release holes were arranged at 10 o'clock and 11:30 azimuths, with a hole depth of 3.5m. At this time, the distance between the tunnel face and the fracture was about 1.8D. Figure 4 shown.

[0093] During the fracture propagation stage: As the TBM continued to advance, at 14:56 on June 26, microseismic monitoring showed that ΔK = 16.68%> 15%, and the distance between the tunnel face and the fracture was about 1.2D. Figure 5 As shown in a, a stress relief hole was constructed in the upper wall of the fault, with a depth of about 8m.

[0094] In the stage of fracture accumulation and fault slip: at 12:00 on June 27, shear anchors were used to penetrate the fault surface at a large angle. At this time, the distance between the tunnel face and the fault was about 0.7D. Figure 6 As shown in a.

[0095] At 4:00 on June 28, the excavation of the face revealed the fracture. During the excavation, the microseismic activity was weak and no arch support was applied. The fault area was then safely passed.

[0096] The method of the present invention can be used to identify the occurrence and location of the fault in advance, and to design targeted step-by-step stress release and support measures according to the occurrence and location of the fault. The timing of applying prevention and control measures can be determined according to the incubation process, thereby curbing the rupture extension and fault slip, and realizing active and precise prevention and control of fault-type rock bursts.

[0097] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or replace some or all of the technical features therein with equivalents. However, these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A method for actively preventing and controlling the fracture-type rockburst incubation process in a deep buried tunnel, characterized in that: include: The microseismic monitoring system arranged behind the tunnel face can monitor the microseismic event information during the excavation process in real time; Before the fault is exposed, determine whether there is a fault in front of the tunnel face, the fault's occurrence, the mileage of the fault intersection with the tunnel crown, and the direction in which the tunnel crosses the fault based on the microseismic event information; Determine the fault-type rockburst grade and fault-type rockburst incubation stage through microseismic event information; Dynamically adjust the fracture-type rockburst prevention and control measures according to the fracture-type rockburst risk level, fracture-type rockburst incubation stage, and the direction of the tunnel crossing the fracture: At the rupture initiation stage, the timing of taking measures to reduce the stress concentration of the tunnel surrounding rock is determined according to the cumulative apparent volume sudden increase rate of adjacent microseismic events to inhibit the occurrence of tensile rupture. In the fracture propagation stage, the timing of arranging stress release holes is selected according to the growth rate of K value to release the closed stress near the fracture; In the fracture accumulation-fracture slip stage, according to the distance between the tunnel face and the fracture, shear anchors or cables are installed to lock the tunnel surrounding rock and the fracture, thus preventing fracture penetration and fracture slip; After the tunnel surrounding rock and the fracture are locked and before the fracture is exposed at the face, appropriate measures are taken according to the fracture-type rock burst risk level until the face passes through the fracture.

2. According to claim 1, a method for actively preventing and controlling the fracture-type rockburst incubation process in a deep buried tunnel is characterized in that: The microseismic event information includes: The number of microseismic events, the energy released by microseismic events, and the three-dimensional coordinates of rock fracture events in space.

3. According to claim 1, a method for actively preventing and controlling the fracture-type rockburst incubation process in a deep buried tunnel is characterized in that: Before the fault is exposed, the microseismic event information is used to determine whether there is a fault in front of the tunnel face, the occurrence of the fault, the mileage of the fault intersecting the tunnel arch, and the direction of the tunnel crossing the fault, including: According to the three-dimensional coordinates of the rock failure event in space and the microseismic release energy, the interpolation method is used to draw the distribution cloud map of the rock failure event space and microseismic release energy in front of the tunnel face; When the rock fracture event space and the microseismic release energy distribution cloud map have linear or strip distribution characteristics, it is determined that there is a fracture in front of the tunnel face, and the extreme value points are connected into a line to represent the fracture and obtain the spatial information of the fracture; Based on the spatial information of the fault, determine the fault occurrence, the mileage of the intersection with the tunnel crown, and the direction of the tunnel crossing the fault; The direction in which the tunnel crosses the fault includes tunneling from the upper wall of the fault to the lower wall and tunneling from the lower wall of the fault to the upper wall.

4. According to claim 1, a method for actively preventing and controlling the fracture-type rockburst incubation process in a deep buried tunnel, characterized in that: The fracture type rock burst levels include: There are non-fracture type rockburst, slight fracture type rockburst, moderate fracture type rockburst, strong fracture type rockburst and extremely strong fracture type rockburst.

5. According to claim 1, a method for actively preventing and controlling the fracture-type rockburst incubation process in a deep buried tunnel, characterized in that: Determining the incubation stage of fracture-type rockburst by using microseismic event information includes: When the number of daily accumulated microseismic events is less than 20 and all of them are tensile ruptures with release energy less than 1000 J, it is judged to be the rupture initiation stage; When the daily cumulative number of microseismic events is 20 to 40, and contains more than three rupture events with release energy higher than 1000 J, it is judged to be the rupture extension stage; When the cumulative number of microseismic events per day is greater than 40 and contains more than one shear rupture event with a release energy greater than 10,000 J, it is judged to be the rupture accumulation-fault slip stage.

6. The method for actively preventing and controlling the fracture-type rockburst incubation process in a deep tunnel according to claim 1, characterized in that: In the rupture initiation stage, according to the cumulative apparent volume sudden increase rate of adjacent microseismic events, the timing of taking measures to reduce the stress concentration of the tunnel surrounding rock is determined to suppress the occurrence of tension rupture, including: When it is determined to be a medium-fracture rockburst and the cumulative apparent volume increase rate of adjacent microseismic events is greater than 45%, the excavation rate is reduced; When it is determined to be a strong fracture type rockburst or an extremely strong fracture type rockburst, and the value of the cumulative apparent volume increase rate of adjacent microseismic events is greater than 45%, the excavation rate is reduced and radial stress relief holes are set vertically on the surrounding rock surface; The depth of the stress release hole exceeds the depth of the microseismic event concentration area.

7. The method for actively preventing and controlling the fracture-type rockburst incubation process in a deep tunnel according to claim 1, characterized in that: In the fracture propagation stage, the timing of arranging stress release holes is selected according to the growth rate of K value to release the closed stress near the fracture, including: When the direction of the tunnel crossing the fault is that the tunnel is excavated from the upper wall of the fault to the lower wall, and the K value growth rate is greater than 15%, a stress relief hole is arranged on the upper wall of the fault, and the hole depth of the stress relief hole exceeds the stress concentration zone; When the direction of the tunnel crossing the fracture is that the tunnel is excavated from the lower wall of the fracture to the upper wall, and the K value growth rate is greater than 17%, stress relief holes are arranged on the fracture surface, and the hole depth of the stress relief holes exceeds the fracture surface.

8. The method for actively preventing and controlling the fracture-type rockburst incubation process in a deep tunnel according to claim 1, characterized in that: In the stage of fracture accumulation and fracture slip, according to the distance between the tunnel face and the fracture, shear anchors or anchor cables are installed to lock the tunnel surrounding rock and the fracture, and to prevent fracture penetration and fracture slip, including: When the direction of the tunnel crossing the fault is from the upper wall to the lower wall, shear anchors or cables are used to pass through the fault surface 0.8 times the tunnel diameter in advance; When the direction of the tunnel crossing the fault is from the lower wall of the fault to the upper wall, shear anchors or cables are used to pass through the fault surface in advance of one time the tunnel diameter; The intersection angle between the shear anchor rod or anchor cable and the fracture surface is greater than 45°.

9. The method for actively preventing and controlling the fracture-type rockburst incubation process in a deep tunnel according to claim 1, characterized in that: After the tunnel surrounding rock and the fracture are locked and before the fracture is exposed at the tunnel face, corresponding measures are taken according to the fracture type rock burst risk level until the tunnel face passes through the fracture, including: When the risk level of fracture-type rockburst drops to medium or below, arch support will not be carried out, and attention will be paid to microseismic activities until the tunnel face passes through the fracture area safely; When the risk level of fracture-type rock burst is severe or above, arch support is carried out according to the direction in which the face crosses the fracture.

10. The method for actively preventing and controlling the fracture-type rockburst incubation process in a deep buried tunnel according to claim 9, characterized in that: The arch support is performed according to the direction in which the tunnel passes through the fracture, including: When the tunnel face passes through the fault in the direction of passing through the upper plate of the fault, the arch frame is installed when the distance between the tunnel face and the fault is 0.5 times the tunnel diameter, until the tunnel face passes through 0.8 times the tunnel diameter of the fault; When the direction of the tunnel face passing through the fault is that the tunnel face passes through the bottom plate of the fault, when the tunnel face is 0.8 times the tunnel diameter away from the fault, the arch frame is installed until the tunnel face passes through 0.5 times the tunnel diameter of the fault.

Images