Stress relief blasting method for near-area rock mass of tunnel face of TBM expanding excavation pilot tunnel

Abstract

The invention relates to the technical field of deep-buried tunnel TBM expanding excavation, and discloses a stress relief blasting method for a near-area rock mass of a TBM expanding excavation pilot tunnel face. The method comprises the following steps: firstly, based on tunnel parameters, pilot tunnel parameters and geological parameters, determining a stress release range and a stress relief blasting depth which need to be performed; and then, based on the blasting vibration threshold value, the site coefficient, the attenuation parameter and the stress relief blasting depth, the stress relief blasting explosive load for ensuring the safety of the TBM equipment is determined. And then, based on the stress relief blasting charge amount and the number of the stress relief blasting holes, determining the length of the stress relief blasting crack actually generated by simulation. And finally, under the condition that it is determined that the length of the stress relief blasting crack actually generated through simulation meets the preset condition, the stress concentration degree of the near-area rock mass of the TBM expanding excavation pilot tunnel face is reduced by arranging the charging stress relief blasting holes with the number equal to that of the stress relief blasting holes in the stress release range, and the stress relief blasting crack is obtained. And the rock burst risk of the near-area rock mass of the tunnel face of the TBM expanding excavation pilot tunnel is reduced.

Description

Technical Field

[0001] The present invention relates to the technical field of TBM excavation of deep-buried tunnels, and in particular to a stress relief blasting method for rock masses near a TBM excavation pilot tunnel face. Background Art

[0002] During the construction of large, deep-buried TBM tunnels, such as those used in water conservancy and hydropower projects and transportation projects, a construction method that involves pre-excavating a pilot tunnel by drilling and blasting has been proposed to mitigate the impact of rockburst. However, when the TBM excavates near the pilot tunnel face, local cross-sectional discontinuities and irregularities can create a stress concentration area between the TBM excavation section and the pilot tunnel section. This stress concentration results in significant stress and energy release in this area, increasing the risk of localized rockburst. Therefore, when the TBM excavates near the pilot tunnel face, it is necessary to control the stress concentration level in this area to ensure the safety and efficiency of TBM construction.

[0003] Therefore, based on the problem of rock burst risk in the rock mass near the tunnel face of the TBM excavation pilot tunnel in the deep tunnel, it is necessary to propose a stress relief blasting method for the rock mass near the tunnel face of the TBM excavation pilot tunnel. Summary of the Invention

[0004] The embodiments of this specification aim to solve at least one of the technical problems in the related art to a certain extent. To this end, the embodiments of this specification propose a stress relief blasting method for rock mass near the tunnel face of a TBM excavation pilot tunnel.

[0005] The embodiments of this specification provide a stress relief blasting method for rock mass near the tunnel face of a TBM excavation pilot tunnel, the method comprising:

[0006] Determine the required stress relief range and stress relief blasting depth based on tunnel parameters, pilot hole parameters and geological parameters;

[0007] Determining a stress relief blasting charge based on a blasting vibration threshold, a site coefficient, an attenuation parameter, and the stress relief blasting depth;

[0008] Determining the length of the simulated actual stress relief blasting crack based on the stress relief blasting charge and the number of stress relief blasting holes;

[0009] When it is determined that the length of the stress relief blasting crack actually generated by the simulation meets the preset conditions, the stress concentration level of the rock mass near the TBM excavation pilot tunnel face is reduced by arranging the number of stress relief blasting holes with explosives within the stress release range.

[0010] In one embodiment, the blasting vibration threshold is determined by:

[0011] Determining, based on the equipment parameters of the TBM, peak blasting vibrations that multiple components can withstand;

[0012] The minimum value among the blasting vibration peak values ​​that the multiple components can withstand is used as the blasting vibration threshold.

[0013] In one embodiment, determining the simulated actual stress relief blasting crack length based on the stress relief blasting charge and the number of stress relief blasting holes includes:

[0014] Determining a single-hole charge according to the stress relief blasting charge and the number of stress relief blasting holes;

[0015] Determining the single-hole blast crack extension length based on the single-hole charge and rock mechanical properties;

[0016] The length of the stress relief blasting crack actually generated in the simulation is determined based on the single-hole blasting crack extension length and the number of the stress relief blasting holes.

[0017] In one embodiment, the number of stress relief blasting holes is the sum of the number of stress relief blasting holes in the TBM expansion area and the number of stress relief blasting holes in the pilot tunnel area. Based on the single-hole blasting crack extension length and the number of stress relief blasting holes, the length of the simulated actual stress relief blasting crack is determined, including:

[0018] Determining the length of the stress relief blasting cracks actually generated in the TBM excavation area by simulating the stress relief blasting cracks based on the single-hole blasting crack extension length and the number of stress relief blasting holes in the TBM excavation area;

[0019] The length of the stress relief blasting crack actually generated in the simulated pilot tunnel area is determined based on the single-hole blasting crack extension length and the number of stress relief blasting holes in the pilot tunnel area.

[0020] In one embodiment, the tunnel parameters include the diameter of the TBM excavated tunnel and the diameter of the pilot tunnel, and the number of stress relief blasting holes in the TBM excavation area and the number of stress relief blasting holes in the pilot tunnel area are determined by the following method:

[0021] Based on the relative proportional relationship between the number of stress relief blasting holes, the diameter of the TBM excavated tunnel and the diameter of the pilot tunnel, the number of stress relief blasting holes in the TBM excavation area and the number of stress relief blasting holes in the pilot tunnel area are determined.

[0022] In one embodiment, determining whether the length of the simulated stress relief explosion crack actually generated satisfies a preset condition includes:

[0023] Determining that a relative difference between a length of a stress relief blasting crack actually generated in the simulation of the TBM excavation area and a length of a stress relief blasting crack theoretically required in the TBM excavation area is within a preset range;

[0024] It is determined that the relative difference between the stress relief blasting crack length actually generated by the simulation of the pilot tunnel region and the stress relief blasting crack length theoretically required for the pilot tunnel region is within a preset range.

[0025] In one embodiment, the tunnel parameters include the diameter of the TBM excavated tunnel, and determining the stress relief blasting crack length theoretically required for the TBM excavation area includes: determining the stress relief blasting crack length theoretically required for the TBM excavation area based on the TBM excavated tunnel diameter and the stress release range.

[0026] In one embodiment, the tunnel parameters include a pilot tunnel diameter, and determining the stress relief blasting crack length theoretically required for the pilot tunnel region includes: determining the stress relief blasting crack length theoretically required for the pilot tunnel region based on the pilot tunnel diameter and the stress release range.

[0027] In one embodiment, the arrangement of the stress relief blasting holes within the stress release range comprises:

[0028] Arrange the number of stress relief blasting holes required for the stress relief blasting in the TBM expansion area within the stress release range within the theoretical stress relief blasting crack length range;

[0029] Within the range of stress relief blasting crack length theoretically required for the pilot hole area in the stress release range, charged stress relief blasting holes having the same number as the stress relief blasting holes in the pilot hole area are arranged.

[0030] In one embodiment, the method further comprises:

[0031] When it is determined that the length of the stress relief blasting crack actually generated by the simulation does not meet the preset conditions, the stress relief blasting charge or the number of stress relief blasting holes is adjusted until the length of the stress relief blasting crack actually generated by the simulation meets the preset conditions.

[0032] In the above-mentioned embodiment, first, the required stress release range and stress relief blasting depth are determined based on the tunnel parameters, pilot tunnel parameters, and geological parameters. Next, the stress relief blasting charge to ensure the safety of the TBM equipment is determined based on the blasting vibration threshold, site coefficient, attenuation parameter, and stress relief blasting depth. Then, based on the stress relief blasting charge and the number of stress relief blasting holes, the length of the simulated stress relief blasting cracks actually generated is determined. Finally, when it is determined that the length of the simulated stress relief blasting cracks actually generated meets the required stress release range, the stress relief blasting holes with the required number of charge are arranged within the stress release range to reduce the stress concentration in the rock mass near the TBM excavation pilot tunnel face, thereby reducing the risk of rock burst in the rock mass near the TBM excavation pilot tunnel face. In addition, the use of blasting improves the stress relief effect of the rock mass near the TBM excavation pilot tunnel face, and construction can be carried out during the TBM shutdown and maintenance period to ensure that the construction progress of the TBM expansion is not affected. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] Figure 1a A schematic flow chart of a stress relief blasting method for rock mass near the face of a TBM excavation pilot tunnel provided in an embodiment of this specification;

[0034] Figure 1b A schematic diagram of the rock mass near the face of a TBM excavating a pilot tunnel provided in an embodiment of this specification;

[0035] Figure 1c A schematic diagram of a crack surface formed by stress relief explosion required for the theory provided in the embodiments of this specification;

[0036] Figure 1d A schematic diagram of a stress relief blasting axial charge structure provided in an embodiment of this specification;

[0037] Figure 2 A schematic diagram of a process for determining a blasting vibration threshold provided in an embodiment of this specification;

[0038] Figure 3 A schematic diagram of a process for determining the length of a simulated stress relief explosion crack actually generated in an embodiment of this specification;

[0039] Figure 4a A schematic diagram of a process for determining the length of a simulated stress relief explosion crack actually generated in an embodiment of this specification;

[0040] Figure 4b A schematic diagram of a simulated stress relief explosion crack surface actually produced in an embodiment of this specification;

[0041] Figure 5A schematic diagram of a process for determining a situation where the length of a simulated stress relief explosion crack actually generated satisfies a preset condition according to an embodiment of the present specification;

[0042] Figure 6a A schematic diagram of a process for arranging the number of pilot hole stress relief blasting holes provided in an embodiment of this specification;

[0043] Figure 6b This is a schematic diagram of the distribution of stress relief blasting holes provided in the embodiments of this specification. DETAILED DESCRIPTION

[0044] The following describes embodiments of the present invention in detail, examples of which are shown in the accompanying drawings, wherein the same or similar reference numerals throughout represent the same or similar elements or elements having the same or similar functions. The embodiments described below with reference to the accompanying drawings are exemplary and are intended to be used to explain the present invention, and are not to be construed as limiting the present invention.

[0045] During the construction of large, deep-buried TBM (Tunnel Boring Machine) tunnels in water conservancy and hydropower projects, transportation projects, and other projects, a construction method that uses drilling and blasting to excavate a pilot tunnel has been proposed to mitigate the impact of rockbursts. However, when the TBM excavates near the pilot tunnel face, a stress concentration area will form between the TBM excavation section and the pilot tunnel section due to discontinuities and irregularities in the local cross-section. This stress concentration causes significant stress and energy release in this area, increasing the risk of local rockburst. Therefore, when the TBM excavates near the pilot tunnel face, the stress concentration level in this area needs to be controlled to ensure the safety and efficiency of TBM construction.

[0046] Based on this, an embodiment of this specification provides a stress relief blasting method for rock mass near the face of a TBM (Tunnel Bored Machine) expansion pilot tunnel. First, the required stress relief range and stress relief blasting depth are determined based on tunnel parameters, pilot tunnel parameters, and geological parameters. Next, the stress relief blasting charge required to ensure TBM equipment safety is determined based on the blasting vibration threshold, site coefficient, attenuation parameter, and stress relief blasting depth. Then, the simulated actual stress relief blasting crack length is determined based on the stress relief blasting charge and the number of stress relief blasting holes. Finally, if it is determined that the simulated actual stress relief blasting crack length meets preset conditions, stress relief blasting holes with the required number of charges are arranged within the stress relief range to reduce stress concentration in the rock mass near the face of the TBM (Tunnel Bored Machine) expansion pilot tunnel, thereby reducing the risk of rockburst in the rock mass near the face of the TBM (Tunnel Bored Machine) expansion pilot tunnel. Furthermore, the use of blasting improves the stress relief effect on the rock mass near the face of the TBM (Tunnel Bored Machine) expansion pilot tunnel, and construction can be performed during TBM downtime and maintenance, ensuring that the TBM expansion construction progress is not affected.

[0047] This specification provides a method for stress relief blasting of rock mass near the face of a TBM excavation pilot tunnel. Figure 1a , the method may include the following steps:

[0048] S110. Determine the required stress release range and stress relief blasting depth based on tunnel parameters, pilot hole parameters, and geological parameters.

[0049] In some cases, during TBM construction, when the TBM is excavated near the pilot tunnel face, due to the discontinuity and irregularity of the local section, a stress concentration area will be formed between the TBM excavation section and the pilot tunnel section, resulting in greater stress and energy release when the TBM is excavated to this area, increasing the risk of local rock burst.

[0050] Specifically, because the annular cracks formed by stress-relieving blasting vary in their ability to isolate stress from the rock mass near the TBM excavation pilot tunnel face, numerical simulation methods are required to more accurately assess the distribution of stress concentration. During the simulation, tunnel parameters, pilot tunnel parameters, and geological parameters are comprehensively considered to determine the theoretically optimal stress-relieving range required for TBM excavation. Furthermore, numerical simulation can be used to ensure that the drilling depth from the stress-relieving blasting charge section to the TBM tunnel face exceeds the local stress concentration zone. This allows the cracks formed by the stress-relieving blasting to isolate the rock mass from stress compression, reducing disturbances during TBM excavation. This allows the stress-relieving blasting depth (i.e., the drilling depth from the charge section to the TBM tunnel face) to be determined. It should be noted that the stress-relieving angle can be determined based on the stress-relieving range, and this stress-relieving angle is less than the maximum drilling angle within the TBM's construction space.

[0051] For example, see Figure 1b , Figure 1b 2 is the TBM excavation face, 3 is the through stress concentration area, 4 is the pilot tunnel, and 5 is the pilot tunnel face.

[0052] See also Figure 1c θ is the stress release angle, and the area corresponding to the stress release angle θ is the stress release range. Figure 7 is the pilot tunnel outline, Figure 8 is the theoretical stress relief blasting crack surface in the pilot tunnel area, and Figure 9 is the theoretical stress relief blasting crack surface in the TBM excavation area.

[0053] S120. Determine the stress relief blasting charge based on the blasting vibration threshold, the site coefficient, the attenuation parameter, and the stress relief blasting depth.

[0054] Specifically, the site coefficient and attenuation parameter are obtained by fitting the on-site blasting test. Then, the blasting vibration threshold, site coefficient, attenuation parameter and stress relief blasting depth are used as parameters, and the blasting vibration attenuation formula is used to calculate and determine the stress relief blasting charge. For example, according to the blasting vibration attenuation formula Back-calculate the stress relief blasting charge Q. Where v is the blasting vibration threshold, k is the site coefficient, α is the attenuation coefficient, and R is the stress relief blasting depth.

[0055] S130: Determine the length of the stress relief blasting cracks actually generated by simulating the stress relief blasting charge and the number of stress relief blasting holes.

[0056] S140. When it is determined that the length of the stress relief blasting crack actually generated by the simulation meets the preset conditions, the stress concentration of the rock mass near the tunnel face of the TBM excavation pilot tunnel is reduced by arranging a number of stress relief blasting holes with explosives within the stress release range.

[0057] Specifically, the stress relief blasting charge and the number of stress relief blasting holes can be used to determine the length of the single-hole blast crack corresponding to each stress relief blasting hole. Next, the total simulated actual stress relief blast crack length is calculated based on the number of stress relief blasting holes and compared with preset conditions. If the simulated actual stress relief blast crack length meets the preset conditions, the stress relief blasting charge and the number of stress relief blasting holes are considered reasonable. Then, the stress relief blasting holes are arranged within the stress release range, with the charge of each stress relief blasting hole being consistent. Next, the stress relief blasting holes are charged. Finally, simultaneous bottom detonation is used to ensure uniform stress relief, thereby reducing stress concentration in the rock mass near the face of the TBM excavation pilot tunnel. It should be noted that after the stress relief blasting is completed, ventilation and smoke exhaust are immediately carried out to ensure a safe working environment. TBM excavation then begins, and during excavation, the rockburst risk is tracked in real time using a microseismic monitoring system. Data analysis assesses the impact of this implementation on rockburst risk, allowing timely adjustments to the excavation strategy. The preset condition may be that the relative difference between the actual length of the simulated stress relief burst and the theoretically desired burst length is within a preset range. For example, the preset condition may be that the relative difference between the actual length of the simulated stress relief burst and the theoretically desired burst length is within 10%.

[0058] For example, see Figure 1d , 14 is a stress relief blasting hole, and 15 is a blasting charge location of the blast hole.

[0059] In the above-described embodiment, first, the required stress release range and stress relief blasting depth are determined based on tunnel parameters, pilot tunnel parameters, and geological parameters. Next, the stress relief blasting charge required to ensure the safety of the TBM equipment is determined based on the blasting vibration threshold, site coefficient, attenuation parameter, and stress relief blasting depth. Then, the simulated actual stress relief blasting crack length is determined based on the stress relief blasting charge and the number of stress relief blasting holes. Finally, if it is determined that the simulated actual stress relief blasting crack length meets preset conditions, the stress concentration in the rock mass near the TBM pilot tunnel face is reduced by arranging the required number of stress relief blasting holes within the stress release range, thereby reducing the risk of rock burst in the rock mass near the TBM pilot tunnel face. Furthermore, the use of blasting improves the stress relief effect on the rock mass near the TBM pilot tunnel face, and construction can be carried out during TBM downtime and maintenance, ensuring that the TBM expansion construction progress is not affected.

[0060] In some embodiments, see Figure 2 , the blasting vibration threshold can be determined by:

[0061] S210 : Determine the peak values ​​of blasting vibrations that the multiple components can withstand based on the equipment parameters of the TBM.

[0062] S220: Taking the minimum value of the blasting vibration peak values ​​that the multiple components can withstand as the blasting vibration threshold.

[0063] Specifically, in order to ensure the safety of each component of the TBM at work during tunnel excavation, a numerical simulation analysis method can be used. First, a comprehensive simulation test is carried out based on the equipment parameters of the TBM. During the simulation test, the peak blasting vibrations that each TBM component (such as the cutterhead and main beam) that is in contact with the surrounding rock of the face is measured and recorded. After determining the peak blasting vibrations that multiple components can withstand, since multiple components are integrated on the TBM and interact and work together in actual work, the vibration effects that all components are subject to must be considered during safety assessments. Therefore, the minimum value of the blasting vibration peaks that multiple components can withstand is needed as the blasting vibration threshold to ensure the safety and stability of the TBM. Among them, the component can be at least one of the TBM main beam, cutterhead, etc. For example, please refer to Figure 1b , Figure 1b The 1 in the figure is the TBM cutterhead.

[0064] In the above embodiment, based on the equipment parameters of the TBM, the blasting vibration peak values ​​that multiple components can withstand are determined, and the minimum value of the blasting vibration peak values ​​that the multiple components can withstand is used as the blasting vibration threshold, thereby improving the safety level in tunnel excavation operations.

[0065] In some embodiments, see Figure 3 , based on the stress relief blasting charge and the number of stress relief blasting holes, determining the length of the simulated actual stress relief blasting crack may include the following steps:

[0066] S310: Determine the charge amount for each hole according to the stress relief blasting charge amount and the number of stress relief blasting holes.

[0067] S320. Determine the single-hole blast crack extension length based on the single-hole charge and rock mechanical properties.

[0068] S330: Determine the length of the stress relief blasting crack actually generated by simulating the stress relief blasting crack based on the single-hole blasting crack extension length and the number of stress relief blasting holes.

[0069] Specifically, first, a set number of stress relief blasting holes is set within the stress release range. The stress relief blasting charge is then divided by the number of stress relief blasting holes to determine the charge for each stress relief blasting hole, i.e., the single-hole charge. Based on the single-hole charge and rock mechanical properties (e.g., principal stress magnitude and rock strength), numerical simulation or theoretical calculation is used to determine the simulated stress relief blasting crack extension length of a single stress relief blasting hole under the given in-situ stress and single-hole charge conditions, i.e., the single-hole blasting crack extension length. Finally, the single-hole blasting crack extension length and the number of stress relief blasting holes are used to calculate the simulated stress relief blasting crack length actually produced by a simulated blasting operation based on the given number of stress relief blasting holes and the stress relief blasting charge.

[0070] In the above embodiment, the single-hole charge is determined based on the stress relief blasting charge and the number of stress relief blasting holes, and the single-hole blasting crack extension length is determined based on the single-hole charge and the rock mechanical properties. Based on the single-hole blasting crack extension length and the number of stress relief blasting holes, the simulated actual stress relief blasting crack length is determined so that it can be subsequently verified with the theoretically required stress relief blasting crack extension length to determine whether the prerequisites for blasting are met.

[0071] In some embodiments, see Figure 4a The number of stress relief blasting holes is the sum of the number of stress relief blasting holes in the TBM expansion area and the number of stress relief blasting holes in the pilot tunnel area. Based on the single-hole blasting crack extension length and the number of stress relief blasting holes, determining the length of the simulated actual stress relief blasting crack may include the following steps:

[0072] S410: Determine the length of the stress relief blasting crack actually generated in the TBM excavation area by simulating the stress relief blasting crack based on the single-hole blasting crack extension length and the number of stress relief blasting holes in the TBM excavation area.

[0073] S420: Determine the length of the stress relief blasting crack actually generated in the simulated pilot tunnel area based on the single-hole blasting crack extension length and the number of stress relief blasting holes in the pilot tunnel area.

[0074] Specifically, the single-hole blast crack extension length represents the extent of crack propagation in the rock mass caused by a stress-relief blast hole with a single-hole charge. To evaluate the overall blasting effectiveness, the single-hole blast crack extension length is multiplied by the number of stress-relief blast holes in the TBM excavation area to determine the simulated actual stress-relief blast crack length in the TBM excavation area. Similarly, the single-hole blast crack extension length is multiplied by the number of stress-relief blast holes in the pilot tunnel area to determine the simulated actual stress-relief blast crack length in the pilot tunnel area.

[0075] For example, see Figure 4b , Figure 4b 12 is the actual stress relief blasting crack surface simulated in the pilot tunnel area, and 13 is the actual stress relief blasting crack surface simulated in the TBM excavation area.

[0076] In the above embodiment, the actual simulated stress relief blasting pattern length of the TBM excavation area is determined based on the single-hole blasting pattern expansion length and the number of stress relief blasting holes in the TBM excavation area. The actual simulated stress relief blasting pattern length of the pilot tunnel area is determined based on the single-hole blasting pattern expansion length and the number of stress relief blasting holes in the pilot tunnel area, so as to be subsequently verified with the theoretically required stress relief blasting pattern expansion length to determine whether the prerequisites for blasting are met.

[0077] In some embodiments, the tunnel parameters include the TBM excavation tunnel diameter and the pilot tunnel diameter, and the number of stress relief blasting holes in the TBM excavation area and the number of stress relief blasting holes in the pilot tunnel area are determined in the following manner: based on the relative proportional relationship between the number of stress relief blasting holes, the TBM excavation tunnel diameter and the pilot tunnel diameter, the number of stress relief blasting holes in the TBM excavation area and the number of stress relief blasting holes in the pilot tunnel area are determined.

[0078] Specifically, two layers of annular blast crack surfaces must be formed at the TBM excavation face and the pilot tunnel face to block the compressive effect of deep-seated high ground stress on the rock mass ahead of the tunnel face, thereby reducing the level of local stress concentration in the rock mass near the TBM excavation pilot tunnel face. Therefore, it is necessary to determine the number of stress-relief blast holes corresponding to each layer. The relative ratio between the TBM excavation tunnel diameter and the pilot tunnel diameter can be determined based on the number of stress-relief blast holes and the relative ratio between the two. Then, based on the number of stress-relief blast holes and the relative ratio between the two, the number of stress-relief blast holes in the TBM excavation area corresponding to the TBM excavation face and the number of stress-relief blast holes in the pilot tunnel area corresponding to the pilot tunnel face are determined.

[0079] For example, the number of stress relief blasting holes in the TBM excavation area Number of stress relief blasting holes in the pilot tunnel area Where D1 is the diameter of the TBM excavated tunnel, D2 is the diameter of the pilot tunnel, and n sum Number of blast holes for stress relief.

[0080] In the above embodiment, based on the number of stress relief blasting holes, the diameter of the TBM excavated tunnel and the diameter of the pilot tunnel, the number of stress relief blasting holes in the TBM excavation area and the number of stress relief blasting holes in the pilot tunnel area are determined, providing a data basis for the subsequent simulation and verification of the actual length of the stress relief blasting cracks.

[0081] In some embodiments, see Figure 5, determining that the length of the stress relief burst crack actually generated by the simulation meets the preset conditions, can include the following steps:

[0082] S510: Determine whether the relative difference between the actual stress relief blasting crack length generated by the TBM excavation area simulation and the theoretical stress relief blasting crack length required for the TBM excavation area is within a preset range.

[0083] S520: Determine whether the relative difference between the actual stress relief blasting crack length generated by the simulation in the pilot tunnel region and the theoretically required stress relief blasting crack length in the pilot tunnel region is within a preset range.

[0084] Specifically, the relative difference between the actual stress-relief blast length generated by the TBM excavation area simulation and the theoretically required stress-relief blast length for the excavation area is calculated by dividing the difference between the actual stress-relief blast length generated by the TBM excavation area simulation and the theoretically required stress-relief blast length for the excavation area by the theoretically required stress-relief blast length for the excavation area, resulting in a percentage error. The relative difference between the actual stress-relief blast length generated by the TBM excavation area simulation and the theoretically required stress-relief blast length for the excavation area is then compared with a preset range. If the relative difference between the actual stress-relief blast length generated by the TBM excavation area simulation and the theoretically required stress-relief blast length for the excavation area is within the preset range, it indicates that the blasting effect meets expectations.

[0085] The relative difference between the actual stress-relief blast length simulated in the pilot tunnel area and the theoretically required stress-relief pilot tunnel blast length for the region is calculated by dividing the difference between the actual stress-relief blast length simulated in the pilot tunnel area and the theoretically required stress-relief blast length for the pilot tunnel area by the theoretically required stress-relief blast length for the pilot tunnel area, resulting in the percentage error. This relative difference between the actual stress-relief blast length simulated in the pilot tunnel area and the theoretically required stress-relief blast length for the pilot tunnel area is then compared to a preset range. If the relative difference between the actual stress-relief blast length simulated in the pilot tunnel area and the theoretically required stress-relief blast length for the pilot tunnel area is within the preset range, it indicates that the blasting effect met expectations.

[0086] In the above embodiment, the relative difference between the actual length of the stress relief blasting pattern generated by the simulation of the TBM excavation area and the theoretical length of the stress relief blasting pattern required for the TBM excavation area is determined to be within a preset range, and the relative difference between the actual length of the stress relief blasting pattern generated by the simulation of the pilot tunnel area and the theoretical length of the stress relief blasting pattern required for the pilot tunnel area is determined to be within a preset range to meet the expected blasting effect, thereby achieving the expected stress release.

[0087] In some embodiments, the tunnel parameters include the TBM excavation tunnel diameter, and determining the stress relief blasting crack length theoretically required for the TBM excavation area includes: determining the stress relief blasting crack length theoretically required for the TBM excavation area based on the TBM excavation tunnel diameter and the stress release range.

[0088] Specifically, the stress release angle can be determined based on the stress release range. When tunnel blasting is in progress, cracks are formed in the surrounding rock due to the blast, and the expansion of the cracks is controlled by the stress release angle. Therefore, using the TBM tunnel diameter and the stress release angle, the stress relief blast crack length theoretically required for the TBM excavation area can be derived. For example, the stress relief blast crack length theoretically required for the TBM excavation area is L TBM =πD1θ / 360, where θ is the stress release angle and D1 is the diameter of the TBM excavated tunnel.

[0089] In the above embodiment, based on the TBM excavation tunnel diameter and the stress release range, the stress relief blasting crack length theoretically required for the TBM excavation area is determined, providing a data basis for subsequent condition verification.

[0090] In some embodiments, the tunnel parameters include a pilot tunnel diameter, and determining the theoretically required stress relief blasting crack length for the pilot tunnel region may include determining the theoretically required stress relief blasting crack length for the pilot tunnel region based on the pilot tunnel diameter and the stress release range.

[0091] Specifically, the stress release angle can be determined based on the stress release range. When the pilot tunnel blasting is carried out, the surrounding rock is cracked by the explosion, and the expansion of the cracks is controlled by the stress release angle. Therefore, using the pilot tunnel diameter and the stress release angle, the stress relief blasting crack length required by the pilot tunnel area theory can be derived. For example, the stress relief blasting crack length L required by the pilot tunnel area theory is 导洞 =πD2θ / 360, where θ is the stress release angle and D2 is the pilot hole diameter.

[0092] In the above embodiment, based on the pilot hole diameter and the stress release range, the stress relief blast crack length theoretically required in the pilot hole region is determined, providing a data basis for subsequent condition verification.

[0093] In some embodiments, see Figure 6a , arranging the number of stress relief blasting holes within the stress release range may include the following steps:

[0094] S610. Arrange the stress relief blasting holes with the same number of explosives as the stress relief blasting holes in the TBM excavation area within the stress release range within the stress relief blasting crack length theoretically required in the TBM excavation area.

[0095] S620. Within the range of stress relief blasting crack length theoretically required in the pilot tunnel area of ​​the stress release range, arrange stress relief blasting holes with the same number of explosives as the stress relief blasting holes in the pilot tunnel area.

[0096] Specifically, after determining that the actual simulated stress relief blasting length meets preset conditions, the specific location corresponding to the theoretically required stress relief blasting length of the TBM excavation area is located within the stress release range according to the stress relief blasting length theoretically required for the TBM excavation area. After determining the location corresponding to the theoretically required stress relief blasting length of the TBM excavation area, a circular arrangement of the same number of charge stress relief blasting holes as those for the TBM excavation area is arranged at equal intervals within the range of the theoretically required stress relief blasting length of the TBM excavation area.

[0097] Based on the theoretically required stress relief blasting length of the pilot tunnel area, the specific location corresponding to the theoretically required stress relief blasting length of the pilot tunnel area is located within the stress release range. After determining the location corresponding to the theoretically required stress relief blasting length of the pilot tunnel area, the pilot tunnel area stress relief blasting holes are arranged at equal intervals within the range of the theoretically required stress relief blasting length of the pilot tunnel area.

[0098] For example, see Figure 6b , θ is the stress release angle, and the area corresponding to the stress release angle θ is the stress release range. 10 is a stress relief blast hole within the theoretical stress relief blast crack length range required in the pilot tunnel area. 11 is a stress relief blast hole within the theoretical stress relief blast crack length range required in the TBM excavation area. Figure 6b The 7 in the figure is the outline of the pilot tunnel.

[0099] In the above embodiment, within the stress relief blasting pattern length range theoretically required for the TBM expansion area within the stress release range, the number of loaded stress relief blasting holes in the TBM expansion area is arranged; within the stress relief blasting pattern length range theoretically required for the pilot tunnel area within the stress release range, the number of loaded stress relief blasting holes in the pilot tunnel area is arranged. This can form two layers of annular blasting pattern surfaces on the TBM expansion face and the pilot tunnel face, blocking the squeezing effect of deep-buried high ground stress on the rock mass in front of the face, thereby reducing the local stress concentration level of the rock mass near the TBM expansion pilot tunnel face and efficiently releasing the stress accumulated in the rock mass.

[0100] In some embodiments, the method may further include: when it is determined that the length of the stress relief blasting crack actually generated by the simulation does not meet the preset conditions, adjusting the stress relief blasting charge or the number of stress relief blasting holes until the length of the stress relief blasting crack actually generated by the simulation meets the preset conditions.

[0101] Specifically, the simulated actual stress relief blasting crack lengths include those in the TBM excavation area and the pilot tunnel area. Crack propagation is influenced by multiple factors, such as the stress relief blasting charge and the number of stress relief blasting holes, which can affect crack propagation length.

[0102] When it is determined that the actual simulated stress relief blasting length of the TBM excavation area or the actual simulated stress relief blasting length of the pilot tunnel area does not meet the preset conditions, in some embodiments, the stress relief blasting charge can be adjusted to be lower than the previous charge, and then the corresponding simulated stress relief blasting length under the adjusted stress relief blasting charge is calculated until the actual simulated stress relief blasting length of the TBM excavation area and the actual simulated stress relief blasting length of the pilot tunnel area both meet the preset conditions. In other embodiments, the number of stress relief blasting holes can be adjusted, and then the corresponding simulated stress relief blasting length under the adjusted number of stress relief blasting holes is calculated until the actual simulated stress relief blasting length of the TBM excavation area and the actual simulated stress relief blasting length of the pilot tunnel area both meet the preset conditions. In some other embodiments, the stress relief blasting charge and the number of stress relief blasting holes can be adjusted simultaneously so that the new stress relief blasting charge is lower than the previous charge, and then the simulated actual stress relief blasting crack length corresponding to the adjusted stress relief blasting charge and the number of stress relief blasting holes is calculated until the simulated actual stress relief blasting crack length in the TBM excavation area and the simulated actual stress relief blasting crack length in the pilot tunnel area both meet the preset conditions.

[0103] For example, the preset condition may be that the relative difference between the actual simulated stress relief blast length and the theoretically required stress relief blast length is within a preset range. For example, the preset condition may be that the relative difference between the actual simulated stress relief blast length in the TBM excavation area and the theoretically required stress relief blast length in the TBM excavation area is within 10%, and the relative difference between the actual simulated stress relief blast length in the pilot tunnel area and the theoretically required stress relief blast length in the pilot tunnel area is within 10%.

[0104] In the above embodiment, when it is determined that the length of the stress relief blasting pattern actually generated by the simulation does not meet the preset conditions, the stress relief blasting charge or the number of stress relief blasting holes is adjusted until the length of the stress relief blasting pattern actually generated by the simulation meets the preset conditions, thereby improving the accuracy of the blasting.

Claims

1. A stress relief blasting method for rock mass near the face of a TBM excavation pilot tunnel, characterized in that: The method comprises: Determine the required stress relief range and stress relief blasting depth based on tunnel parameters, pilot hole parameters and geological parameters; Determining a stress relief blasting charge based on a blasting vibration threshold, a site coefficient, an attenuation parameter, and the stress relief blasting depth; Determining the length of the simulated actual stress relief blasting crack based on the stress relief blasting charge and the number of stress relief blasting holes; When it is determined that the length of the stress relief blasting crack actually generated by the simulation meets the preset conditions, the stress concentration level of the rock mass near the TBM excavation pilot tunnel face is reduced by arranging the number of stress relief blasting holes with explosives within the stress release range.

2. The method according to claim 1, wherein The blasting vibration threshold is determined by: Determining, based on the equipment parameters of the TBM, peak blasting vibrations that multiple components can withstand; The minimum value among the blasting vibration peak values ​​that the multiple components can withstand is used as the blasting vibration threshold.

3. The method according to claim 1, wherein The determining of the simulated actual stress relief blasting crack length based on the stress relief blasting charge and the number of stress relief blasting holes includes: Determining a single-hole charge according to the stress relief blasting charge and the number of stress relief blasting holes; Determining the single-hole blast crack extension length based on the single-hole charge and rock mechanical properties; The length of the stress relief blasting crack actually generated in the simulation is determined based on the single-hole blasting crack extension length and the number of the stress relief blasting holes.

4. The method according to claim 3, wherein The number of stress relief blasting holes is the sum of the number of stress relief blasting holes in the TBM expansion area and the number of stress relief blasting holes in the pilot tunnel area. Based on the single-hole blasting crack extension length and the number of stress relief blasting holes, the length of the simulated actual stress relief blasting crack is determined, including: Determining the length of the stress relief blasting cracks actually generated in the TBM excavation area by simulating the stress relief blasting cracks based on the single-hole blasting crack extension length and the number of stress relief blasting holes in the TBM excavation area; The length of the stress relief blasting crack actually generated in the simulated pilot tunnel area is determined based on the single-hole blasting crack extension length and the number of stress relief blasting holes in the pilot tunnel area.

5. The method according to claim 4, characterized in that The tunnel parameters include the diameter of the TBM excavated tunnel and the diameter of the pilot tunnel. The number of stress relief blasting holes in the TBM excavation area and the number of stress relief blasting holes in the pilot tunnel area are determined by the following method: Based on the relative proportional relationship between the number of stress relief blasting holes, the diameter of the TBM excavated tunnel and the diameter of the pilot tunnel, the number of stress relief blasting holes in the TBM excavation area and the number of stress relief blasting holes in the pilot tunnel area are determined.

6. The method according to claim 4, characterized in that The determining that the length of the stress relief explosion crack actually generated by the simulation meets a preset condition includes: Determining that a relative difference between a length of a stress relief blasting crack actually generated in the simulation of the TBM excavation area and a length of a stress relief blasting crack theoretically required in the TBM excavation area is within a preset range; It is determined that the relative difference between the stress relief blasting crack length actually generated by the simulation of the pilot tunnel region and the stress relief blasting crack length theoretically required for the pilot tunnel region is within a preset range.

7. The method according to claim 6, characterized in that The tunnel parameters include the diameter of the TBM excavated tunnel, and determining the stress relief blasting crack length theoretically required for the TBM excavation area includes: determining the stress relief blasting crack length theoretically required for the TBM excavation area based on the TBM excavated tunnel diameter and the stress release range.

8. The method according to claim 6, characterized in that The tunnel parameters include a pilot tunnel diameter, and determining the stress relief blasting crack length theoretically required for the pilot tunnel region includes: determining the stress relief blasting crack length theoretically required for the pilot tunnel region based on the pilot tunnel diameter and the stress release range.

9. The method according to claim 1, wherein The stress relief blasting holes provided with the same number of charge stress relief blasting holes as described above within the stress relief range include: Arrange the number of stress relief blasting holes required for the stress relief blasting in the TBM expansion area within the stress release range within the theoretical stress relief blasting crack length range; Within the range of stress relief blasting crack length theoretically required for the pilot hole area in the stress release range, charged stress relief blasting holes having the same number as the stress relief blasting holes in the pilot hole area are arranged.

10. The method according to claim 1, wherein The method further comprises: When it is determined that the length of the stress relief blasting crack actually generated by the simulation does not meet the preset conditions, the stress relief blasting charge or the number of stress relief blasting holes is adjusted until the length of the stress relief blasting crack actually generated by the simulation meets the preset conditions.

Images