A method and system for determining the optimal delay time of high-gas tunnel blasting cut holes
By analyzing the rock mechanics and explosive performance parameters of high-gas tunnels and combining them with numerical simulation, the optimal delay time for the cut hole was determined, which solved the problem of insufficient delay segments in traditional detonating devices and achieved efficient blasting effect and safety.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- SHANDONG UNIV OF SCI & TECH
- Filing Date
- 2026-03-17
- Publication Date
- 2026-05-19
AI Technical Summary
There is a lack of research on the optimal delay time for digital electronic detonators in high-gas tunnels, which makes it difficult to achieve the expected blasting effect. In addition, traditional detonating devices have insufficient delay stages, and some auxiliary holes share a single detonation delay, which lacks scientific basis.
By conducting conventional mechanical tests on the surrounding rock at the tunnel face, rock mechanical parameters and explosive performance parameters were obtained. A three-dimensional model of the rock mass to be broken in the cut area was constructed. The rock mass movement was numerically simulated, the characteristics of the rock mass migration stage were analyzed, the optimal delay time was determined, and the detonation delay of each row of blast holes was set to ensure that the total delay time meets the requirements of high-gas tunnels.
The precise design of the optimal delay time for each row of blast holes solved the problem of mismatch between the number of blast hole rows and the number of detonator segments, maximizing the blasting effect, meeting the total delay time requirements for high-gas tunnels, and improving blasting efficiency and safety.
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Figure CN121859672B_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of numerical simulation technology in geotechnical engineering, specifically to a method and system for determining the optimal delay time for blasting cut holes in high-gas tunnels. Background Technology
[0002] In high-gas tunnel blasting operations, the rationality of the detonation delay time directly determines the blasting effect. Traditional detonating devices suffer from insufficient delay segments. On-site detonation times are typically set to fixed delays of 0ms, 25ms, 25ms, 50ms, 75ms, and 100ms. However, this number of delay segments is less than the number of borehole rows, resulting in some auxiliary holes sharing a single detonation delay. Furthermore, the design of the delay time for cut holes lacks scientific basis, leading to blasting effects that are difficult to achieve as expected.
[0003] Digital electronic detonators, as a new type of detonating device, have overcome the shortcomings of ordinary electronic detonators in terms of delay settings and networked control, leading to their increasingly widespread application in tunnel blasting. However, current research on the optimal delay time for digital electronic detonators in high-gas tunnels is limited, failing to provide effective guidance for on-site construction. Therefore, there is an urgent need for a method to determine the delay time for cut holes and multi-row blasting that can accurately match the working conditions of high-gas tunnels while considering both total delay time limitations and blasting effects. Summary of the Invention
[0004] To address the aforementioned problems, this invention provides a method for determining the optimal delay time for blasting cut holes in high-gas tunnels, comprising:
[0005] Conventional mechanical tests were conducted on the surrounding rock area of the tunnel face to obtain the rock mechanical parameters of the surrounding rock at the tunnel face, and the explosive performance parameters of the explosives used in the construction were statistically analyzed.
[0006] Based on the rock mechanics parameters and explosive performance parameters, the time required for rock mass movement during the rock mass crack propagation stage, the rock mass volume increase stage, and the rock mass ejection stage is calculated respectively, and the time required for the rock mass to be broken to be completely ejected is obtained.
[0007] A three-dimensional model of the rock mass to be broken in the slotted area is constructed and post-processed. The three-dimensional model of the rock mass to be broken in the slotted area includes blast holes, plugs, rock SPH particles and rock FEM finite element network.
[0008] Specific monitoring points were selected along the vertical depth direction at the center of the three-dimensional model of the rock mass to be broken in the slotting area. The displacement and velocity time history curves of each monitoring point were obtained through numerical simulation. By analyzing the characteristics of the three stages of rock mass migration, the time node when the free face of the slotting area was completely formed was determined as the optimal delay time for the slotting hole.
[0009] The overall model of the tunnel face was completed based on the three-dimensional model of the rock mass in the cut area. The delay time of the cut holes was set according to the optimal delay time of the cut holes. The detonation of each row of blast holes was simulated in sequence. Based on the rock mass ejection and the formation state of the free face in the numerical simulation, the optimal detonation delay time of each row of blast holes was determined, and the total delay time was ensured to meet the total delay value specified for high gas tunnels.
[0010] The time required for rock mass movement during the crack propagation stage is calculated as follows:
[0011]
[0012] in: d e For the spacing between the bottom of the slotted holes, d P Spacing between slotted holes, c p For the longitudinal wave velocity of the rock mass, K c For rock fracture toughness, t For the tensile strength of rock, m The critical strain rate is denoted as .
[0013] The time required for rock mass movement during the stage of rock mass volume increase is:
[0014]
[0015] in: m To eject the rock mass, A For pressure bearing area, μ For the coefficient of friction, c For viscous damping coefficient, P 0 represents the initial pressure. V 0 represents the initial gas volume. A f For the equivalent area of the crack, v m For gas expansion rate, For gas density, d s For rock mass displacement, d t The time required for the rock mass displacement is given by D, where D is the detonation velocity of the explosive.
[0016] The time required for the rock mass movement during the rock mass ejection stage is calculated as follows:
[0017]
[0018] in: v 0 represents the initial launch velocity. For the launch angle,s 2 represents the size of the resistance line. α The angle of the slotted hole.
[0019] The specific method for constructing the three-dimensional model of the rock mass to be fractured in the slotted area is as follows:
[0020] The scope of the three-dimensional model to be constructed is determined based on the on-site borehole layout data;
[0021] A constitutive model of rock material was constructed based on rock mechanics parameters to create a three-dimensional model of the rock mass to be broken in the slotted area; the rock around the explosives, plugs and blast holes was modeled using SPH particle flow, and the remaining rocks were modeled using FEM finite element method.
[0022] An explosive material model is constructed based on the explosive performance parameters, and the explosive charge in the slotted hole is calculated based on the slotted hole charging structure. A soil model is selected as the plugging method.
[0023] The constructed three-dimensional model of the rock mass to be broken in the slotted area is post-processed, including the SPH particle part and the FEM finite element part respectively, by setting the corresponding keywords to eliminate the influence of boundary reflection waves; and the total time required to eject the rock mass to be broken in the slotted area is used as the total model calculation time, and the interval of the rock mass migration simulation output file is set.
[0024] The specific selection of monitoring points involves selecting SPH particles of the rock mass at equal intervals along the vertical depth direction at the center of the three-dimensional model of the rock mass to be broken in the slotted area.
[0025] The rock mechanical parameters include rock density, shear modulus, longitudinal wave velocity, tensile strength, fracture toughness, and friction coefficient.
[0026] The explosive performance parameters include explosive density, detonation velocity, detonation pressure, initial specific internal energy, and initial relative volume.
[0027] This invention also provides a system for determining the optimal delay time of blasting cut holes in high-gas tunnels, which implements the method for determining the optimal delay time of blasting cut holes as described above. The system includes:
[0028] The parameter acquisition module is used to conduct conventional mechanical tests on the surrounding rock area of the tunnel face, obtain the rock mechanical parameters of the surrounding rock of the tunnel face, and at the same time, statistically analyze the explosive performance parameters of the explosives used in the construction.
[0029] The theoretical time calculation module is used to calculate the time required for rock mass movement during the rock mass crack propagation stage, rock mass volume increase stage, and rock mass ejection stage, respectively, based on rock mechanics parameters and explosive performance parameters, so as to obtain the time required for the rock mass to be broken to be completely ejected.
[0030] The model building module is used to build a three-dimensional model of the rock mass to be broken in the slotted area and perform post-processing. The three-dimensional model of the rock mass to be broken in the slotted area includes blast holes, plugs, rock SPH particles and rock FEM finite element network.
[0031] The monitoring and analysis module is used to select specific monitoring points along the vertical depth direction at the center of the three-dimensional model of the rock mass to be broken in the slotting area, and obtain the displacement and velocity time history curves of each monitoring point through numerical simulation; by analyzing the characteristics of the three stages of rock mass migration, the time node when the free face of the slotting area is completely formed is determined as the optimal delay time for the slotting hole.
[0032] The delay time generation module is used to complete the overall model of the tunnel face based on the three-dimensional model of the rock mass in the cut area. It sets the delay time of the cut holes according to the optimal delay time of the cut holes, simulates the detonation of each row of blast holes in sequence, determines the optimal detonation delay time of each row of blast holes based on the rock mass ejection and the formation state of the free face in the numerical simulation, and ensures that the total delay time meets the total delay time specified for high-gas tunnels.
[0033] Beneficial effects: This invention provides a method and system for determining the optimal delay time for blasting cut holes in high-gas tunnels. By combining theoretical analysis and numerical simulation, it clarifies the rock mass migration law and the timing of free face formation in the cut area, accurately designs the optimal delay time for each row of blast holes, and solves the problem of mismatch between the number of blast hole rows and the number of detonator segments in the prior art. Under the premise of meeting the total delay time requirements of high-gas tunnels, it maximizes the blasting effect.
[0034] By revealing the migration patterns of the rock mass in the cut-out area and combining the rock mass ejection state with specific timing, the optimal detonation delay can be directly selected based on the rock mass ejection state during on-site construction, solving the current problem of insufficient advance of cut-out holes in high-gas tunnels. Simultaneously, the optimal detonation delay time for cut-out holes and other rows of blast holes in high-gas tunnels has been clarified, providing a scientific reference scheme for on-site blasting parameter design, which can be directly applied in the field.
[0035] Finally, the problem of having more rows of blast holes than detonator segments in high-gas tunnels was solved, avoiding the issue of multiple rows of auxiliary holes sharing the same detonation time. All delay settings meet the total delay time requirements for high-gas tunnels, balancing safety and blasting effect, and are suitable for various high-gas tunnel blasting projects. Attached Figure Description
[0036] The solutions and advantages of this application will become clear to those skilled in the art upon reading the following detailed description of preferred embodiments. The accompanying drawings are for illustrative purposes only and are not intended to limit the scope of the invention.
[0037] In the attached diagram:
[0038] Figure 1This is a schematic diagram of the design and distribution of blast holes on the working face in the embodiment;
[0039] Figure 2 This is a schematic diagram of the three-dimensional model of the rock mass to be broken in the slotted area in the embodiment.
[0040] Figure 3 This is a schematic diagram of the slotted hole structure in the embodiment;
[0041] Figure 4 This is a schematic diagram showing the locations of the selected monitoring points in the model of the embodiment;
[0042] Figure 5 This is a schematic diagram of the time history curves of the displacement and velocity of the monitoring point in the embodiment;
[0043] Figure 6 This is a diagram of the overall structure of the tunnel face in the embodiment;
[0044] Figure 7 This is a post-explosion effect diagram of the overall structure of the tunnel face in the embodiment;
[0045] Figure 8 This is a statistical chart showing the utilization rate of the slotted holes in the field test in the embodiment;
[0046] Figure 9 This is a statistical chart showing the post-blast half-hole ratio and linear average over- and under-excavation statistics in the field test examples;
[0047] Figure 10 This is a statistical chart of particle size distribution after the explosion in the field test in the example. Detailed Implementation
[0048] Exemplary embodiments of this disclosure will now be described in more detail with reference to the accompanying drawings.
[0049] Example 1
[0050] This embodiment provides a method for determining the optimal delay time for blasting cut holes in high-gas tunnels, and the specific operation steps are as follows:
[0051] S1. Conduct conventional mechanical tests on the surrounding rock area of the tunnel face to obtain the rock mechanics parameters of the surrounding rock at the tunnel face, and at the same time, compile the explosive performance parameters of the explosives used in the construction.
[0052] Based on the site conditions, representative rock areas were selected within the tunnel face for sampling. Then, conventional mechanical tests were conducted on the samples to determine their rock mechanical parameters.
[0053] The rock mechanical parameters include rock density, shear modulus, longitudinal wave velocity, tensile strength, fracture toughness, and friction coefficient.
[0054] The rock mechanical parameters measured in this embodiment are shown in Table 1 below.
[0055] Table 1 Rock mechanical parameters
[0056]
[0057] Then, the explosive performance parameters of the explosives used in construction were statistically analyzed. These parameters included explosive density, detonation velocity, detonation pressure, initial specific internal energy, and initial relative volume. The explosive performance parameters statistically analyzed in this embodiment are shown in Table 2.
[0058] Table 2 Explosive Parameters
[0059]
[0060] S2. Based on the rock mechanics parameters and explosive performance parameters, calculate the time required for rock mass movement during the rock mass crack propagation stage, rock mass volume increase stage, and rock mass ejection stage, respectively, and obtain the time required for the rock mass to be completely ejected.
[0061] After the explosive in the cut hole is detonated, the rock mass ejection process is affected by the combined action of the explosion stress wave and the explosion gas. The rock mass ejection process is divided into three stages: the rock mass crack propagation stage, the rock mass volume increase stage, and the rock mass ejection stage. By analyzing the rock mass movement patterns at each stage, the time required for rock mass movement at each stage is calculated, and finally, the total time required for the rock mass to be broken in the cut area to be ejected is determined.
[0062] The rock mass crack propagation stage is characterized by the application of explosive energy to the area around the borehole, causing cracks to form in the rock mass. The formula for calculating the time required for rock mass movement during this stage is as follows:
[0063]
[0064] in: d e For the spacing between the bottom of the slotted holes, d P Spacing between slotted holes, c p For the longitudinal wave velocity of the rock mass, K c For rock fracture toughness, t For the tensile strength of rock, m The critical strain rate is denoted as .
[0065] The stage of rock mass volume increase is characterized by explosive gas driving crack propagation and relative displacement on both sides of the rock mass leading to volume increase. The formula for calculating the time required for rock mass movement in this stage is as follows:
[0066]
[0067] in: mTo eject the rock mass, A For pressure bearing area, μ For the coefficient of friction, c For viscous damping coefficient, P 0 represents the initial pressure. V 0 represents the initial gas volume. A f For the equivalent area of the crack, v m For gas expansion rate, For gas density, d s For rock mass displacement, d t D is the time required for the rock mass displacement, and D is the detonation velocity of the explosive.
[0068] The rock mass ejection stage is characterized by the quasi-static pressure of the explosive gas propelling the rock mass outward. The time required for this stage of rock mass movement is calculated using the following formula:
[0069]
[0070] in: v 0 represents the initial launch velocity. For the launch angle, s 2 represents the size of the resistance line. α The angle of the slotted hole.
[0071] The total time required to eject the rock mass to be broken from the slotted area is obtained by summing the results; this is the total time required. T = t 1+ t 2+ t 3.
[0072] S3. Construct a three-dimensional model of the rock mass to be broken in the slotted area and perform post-processing. The three-dimensional model of the rock mass to be broken in the slotted area includes blast holes, plugs, rock SPH particles and rock FEM finite element network.
[0073] The specific method for constructing the three-dimensional model of the rock mass to be fractured in the slotted area is as follows:
[0074] S301. Determine the range of the three-dimensional model to be constructed based on the on-site borehole layout data;
[0075] See Figure 1 This is a diagram showing the layout of the boreholes in this embodiment. The slotted holes are arranged in two rows of eight holes each, with an inclination angle of 69°. The distance between the borehole openings on both sides is 3.6m, and the distance between the bottom holes is 0.3m. Taking the slotted area as the research object, the three-dimensional model range of the rock mass to be broken in the slotted area is determined to be 5.0m × 6.0m × 4.0m. Figure 2 As shown.
[0076] S302. Construct a three-dimensional model of the rock mass to be broken in the slotted area based on rock mechanics parameters; the explosives, plugs and rocks around the blast holes are modeled using SPH particle flow, and the remaining rocks are modeled using FEM finite element method;
[0077] The HJC model was selected as the constitutive model for the rock material. This model can effectively describe the entire process of dynamic damage accumulation in rock under the coupled action of blast stress wave and blast gas, from crack development to fracture. Its damage variables... D Due to plastic strain With plastic volumetric strain Joint control:
[0078]
[0079] in: This represents the plastic strain value. T Maximum standardized tensile strength; D 1. D 2 represents the damage factor; This represents the minimum plastic strain.
[0080] When performing SPH particle processing, the explosives and plugs are generated using the element center method, the rock mass to be blasted is generated using the element common node method, and the rest uses FEM finite element mesh.
[0081] S303. Construct an explosive material model based on the explosive performance parameters, calculate the explosive charge in the slotted hole based on the slotted hole charging structure, and select a soil model as the plugging method.
[0082] In this example, the explosive used is No. 2 rock emulsion explosive. Therefore, the explosive material model is used in conjunction with the JWL equation of state. The JWL equation is as follows:
[0083]
[0084] In the formula: P For pressure; V For the initial relative volume ( P Dimensionless quantity); E 0 represents the initial specific internal energy; in this example, A =214.4 GPa B =0.182 GPa R 1 = 4.2 R 2 = 0.9 =0.15.
[0085] At the same time, such as Figure 3 The diagram shows the slotted hole charging structure of this embodiment. The charge amount per slot is calculated based on this structure using the following formula:
[0086]
[0087] in: Q For single-hole charge amount, q Explosive consumption per unit (kg / m³) 3 ), a is the borehole spacing (m), W is the minimum resistance line size (m), and H is the borehole depth (m).
[0088] The post-processing of the constructed three-dimensional model of the rock mass to be broken in the slotted area includes setting corresponding keywords for the SPH particle part and the FEM finite element part to eliminate the influence of boundary reflection waves; and setting the total time required to eject the rock mass to be broken in the slotted area as the total model calculation time, and setting the interval of the rock mass migration simulation output file.
[0089] S4. Select specific monitoring points along the vertical depth direction at the center of the three-dimensional model of the rock mass to be broken in the slotting area, and obtain the displacement and velocity time history curves of each monitoring point through numerical simulation; by analyzing the characteristics of the three stages of rock mass migration, determine the time node when the free face of the slotting area is completely formed, and use it as the optimal delay time for the slotting hole.
[0090] The rock mass migration pattern in the cut area was analyzed based on numerical simulation results, and the rock mass ejection situation in different time periods was statistically analyzed. To further analyze the movement of the rock mass to be blasted, SPH particles were selected at equal intervals along the vertical depth direction at the center of the face of the 3D model as monitoring points. In this example, the monitoring points were spaced 1.0m apart. (See [reference needed]). Figure 4 As shown.
[0091] like Figure 5 As shown, the left figure is the displacement time history curve of the monitoring point, and the right figure is the velocity time history curve of the monitoring point. Through... Figure 5It can be observed that under the combined action of blasting stress wave and explosive gas, the rock mass migration in the cut area can be divided into three stages: The first stage is the fracture propagation stage. During this process, the explosive energy mainly acts on the rock mass around the borehole, causing it to fracture. At this time, the particle displacement and velocity at measuring points A to D are basically zero, and the rock mass to be blasted has not moved. The second stage is the rock mass volume increase stage in the cut area. Due to the influence of the detonation method, during this process, the particles at measuring points A and B undergo a certain displacement towards the bottom of the borehole, while the particles at measuring points C and D begin to move outward under the push of the explosive gas. Under the combined action of the stress wave and the explosive gas, the particle velocity at measuring points C and D increases sharply. The relative displacement on both sides of the rock mass increases the volume of the rock mass in the cut area. At this time, the rock mass to be blasted is moving outward as a whole, but the speed is relatively slow. The third stage is the rock mass ejection stage in the cut area. In this stage, as the crack at the bottom of the blast hole expands, the quasi-static pressure of the explosive gas generates a huge thrust on the rock mass as a whole. At this time, the displacement direction of measuring points A and B changes and begins to move outward. Under the action of the explosive gas, measuring points C and D continue to move, but the velocity remains basically unchanged.
[0092] After the third stage begins (T=40ms), the cavity formed in the cut area is sufficient to meet the free face required for subsequent blasting, and the subsequent movement of rock mass has little impact on the blasting effect. Considering that this tunnel is a high-gas tunnel, the following regulations should be met when using coal mine-specific digital electric detonators:
[0093] (1) The delay time of the last segment shall not exceed 130 ms.
[0094] (2) The total time difference of a single detonation shall not exceed 130ms and shall be used in conjunction with a dedicated detonator.
[0095] Therefore, under the premise of meeting the requirements, in order to ensure the blasting effect, this example selects 40ms as the optimal detonation delay for the slotted hole.
[0096] S5. Complete the overall model of the tunnel face based on the three-dimensional model of the rock mass in the cut area. Set the delay time of the cut holes according to the optimal delay time of the cut holes. Simulate the detonation of each row of blast holes in sequence. Determine the optimal detonation delay time of each row of blast holes based on the rock mass ejection and the formation state of the free face in the numerical simulation, and ensure that the total delay time meets the total delay value specified for high gas tunnels.
[0097] according to Figure 1As shown, this embodiment arranges six rows of blast holes, with a peripheral hole spacing of 0.5m, an inner hole spacing of 0.8m, a blast layer thickness of 0.6m, and blast hole inclination angles from the slotting hole to the peripheral hole of 69°, 78°, 79°, 84°, 90°, and 92° respectively. Based on this blast hole layout diagram, the remaining part of the tunnel face is completed. Using the three-dimensional model of the rock mass in the slotting area as a basis, the arch waist position of the tunnel face is cut. See [reference needed]. Figure 6 As shown, the optimal detonation delay for each row of blast holes is analyzed from the perspective of this cross-section.
[0098] Using this cross-section as the research object, a quasi-three-dimensional plane of 15.0m × 5.0m × 4.4cm was established, including boreholes, plugging, rock SPH particles, and rock FEM finite element mesh. Except for the peripheral boreholes which used an intermittent charging structure, the remaining boreholes all used a continuous charging structure. To eliminate the influence of reflected waves at the boundaries on the rock mass structure, all boundaries except the excavation face were non-reflective boundaries. In the delay settings of this numerical simulation, to study the rock ejection patterns of the remaining rows of boreholes, except for the first row of auxiliary boreholes which was delayed by 40ms, the delay for the remaining rows of boreholes was set to 50ms to ensure that the free face required for subsequent blasting could be fully formed.
[0099] During tunnel blasting, the rock mass is primarily thrown towards the free face formed by the cut holes. For the first ring of auxiliary holes adjacent to the cut cavity, this throwing direction is approximately perpendicular to the tunnel face and points towards the tunnel interior. As blasting progresses, the free face expands outwards, and the rock mass broken by the outer ring of auxiliary holes also moves towards this gradually expanding space. In the post-processing analysis of this simulation, to identify the formation process of the free face, units with damage values between 0.9 and 1 are hidden in the damage cloud map display settings. The evolution process of surrounding rock damage is as follows: Figure 7 As shown.
[0100] Depend on Figure 7 It can be seen that before the first row of auxiliary holes was detonated, approximately one-third of the total cut volume of rock had been thrown outwards from the working face, creating cavities that fully met the requirements for free face in subsequent blasting. As each row of blast holes was detonated sequentially, the first two rows of auxiliary holes were detonated by T=60ms. The rock damage distribution showed that the rock inside the blast holes was completely fractured, and the rock near the hole opening began to move outwards, resulting in a good free face formation within the blast holes. By T=80ms, the third and fourth rows of auxiliary holes were completely detonated, and the formation of their internal free faces was similar to the first two rows, effectively ensuring the smooth progress of subsequent blasting. By T=100ms, the inner ring of auxiliary holes was detonated, creating favorable free face conditions for the surrounding holes. By T=120ms, when the surrounding holes were detonated, the damage state of the surrounding rock showed a small damage range, indicating that the disturbance to the surrounding rock by the blasting was effectively controlled.
[0101] In this example, the time it takes for one-third of the rock mass to be ejected from the first row of auxiliary holes is approximately 20-24 ms. The resulting cavity is sufficient to provide the free face required for subsequent blasting. Therefore, the optimal detonation delay for this row of holes is set to 20-24 ms. Based on this, the optimal detonation delays for the remaining rows of holes can be calculated sequentially. According to the numerical simulation results and field conditions, the delay time settings for each row of holes are shown in Table 3 below. It can be seen that under this delay setting, the total delay time for the holes is 120 ms, which meets the total delay requirements for high-gas tunnels.
[0102] Table 3. Detonation delay time settings for each row of blast holes (ms)
[0103]
[0104] To verify the method of this embodiment, the above-obtained borehole charge was applied in the field, and the post-explosion effects were statistically analyzed. (See attached document.) Figure 8 , Figure 9 and Figure 10 As shown, when the slot hole delay is 40ms, the slot hole utilization rate is about 90%. At this time, the slotted area can fully guarantee the advance. When other blast holes are set according to the delay time given in Table 3, the post-blast half-hole rate is above 85%, the linear average over-excavation is about 20cm, the overall outline is well controlled, and the initial support cost and over- and under-excavation construction cost are greatly reduced.
[0105] Furthermore, this embodiment also provides a system for determining the optimal delay time for blasting cut holes in high-gas tunnels, including:
[0106] The parameter acquisition module is used to conduct conventional mechanical tests on the surrounding rock area of the tunnel face, obtain the rock mechanical parameters of the surrounding rock of the tunnel face, and at the same time, statistically analyze the explosive performance parameters of the explosives used in the construction.
[0107] The theoretical time calculation module is used to calculate the time required for rock mass movement during the rock mass crack propagation stage, rock mass volume increase stage, and rock mass ejection stage, respectively, based on rock mechanics parameters and explosive performance parameters, so as to obtain the time required for the rock mass to be broken to be completely ejected.
[0108] The model building module is used to build and post-process a three-dimensional model of the rock mass to be broken in the slotted area. The three-dimensional model of the rock mass to be broken in the slotted area includes blast holes, plugs, rock SPH particles and rock FEM finite element network.
[0109] The monitoring and analysis module is used to select specific monitoring points along the vertical depth direction at the center of the three-dimensional model of the rock mass to be broken in the slotting area, and obtain the displacement and velocity time history curves of each monitoring point through numerical simulation; by analyzing the characteristics of the three stages of rock mass migration, the time node when the free face of the slotting area is completely formed is determined as the optimal delay time for the slotting hole.
[0110] The delay time generation module is used to complete the overall model of the tunnel face based on the three-dimensional model of the rock mass in the cut area. It sets the delay time of the cut holes according to the optimal delay time of the cut holes, simulates the detonation of each row of blast holes in sequence, determines the optimal detonation delay time of each row of blast holes based on the rock mass ejection and the formation state of the free face in the numerical simulation, and ensures that the total delay time meets the total delay time specified for high-gas tunnels.
[0111] Of course, the above description is only a preferred embodiment of the present invention. The present invention is not limited to the above-described embodiments. It should be noted that any equivalent substitutions or obvious modifications made by those skilled in the art under the guidance of this specification fall within the scope of this specification and should be protected by the present invention.
Claims
1. A method for determining the optimal delay time for blasting cut holes in high-gas tunnels, characterized in that, include: Conventional mechanical tests were conducted on the surrounding rock area of the tunnel face to obtain the rock mechanical parameters of the surrounding rock at the tunnel face, and the explosive performance parameters of the explosives used in the construction were statistically analyzed. Based on the rock mechanics parameters and explosive performance parameters, the time required for rock mass movement during the rock mass crack propagation stage, the rock mass volume increase stage, and the rock mass ejection stage is calculated respectively, and the time required for the rock mass to be broken to be completely ejected is obtained. A three-dimensional model of the rock mass to be broken in the slotted area is constructed and post-processed. The three-dimensional model of the rock mass to be broken in the slotted area includes blast holes, plugs, rock SPH particles and rock FEM finite element network. Specific monitoring points were selected along the vertical depth direction at the center of the three-dimensional model of the rock mass to be broken in the slotting area. The displacement and velocity time history curves of each monitoring point were obtained through numerical simulation. By analyzing the characteristics of the three stages of rock mass migration, the time node when the free face of the slotting area was completely formed was determined as the optimal delay time for the slotting hole. The overall model of the tunnel face was completed based on the three-dimensional model of the rock mass in the cut area. The delay time of the cut holes was set according to the optimal delay time of the cut holes. The detonation of each row of blast holes was simulated in sequence. Based on the rock mass ejection and the formation state of the free face in the numerical simulation, the optimal detonation delay time of each row of blast holes was determined, and the total delay time was ensured to meet the total delay value specified for high gas tunnels.
2. The method for determining the optimal delay time for blasting cut holes in high-gas tunnels according to claim 1, characterized in that, The time required for rock mass movement during the rock fracture propagation stage is calculated as follows: ， in: d e For the spacing between the bottom of the slotted holes, d P Spacing between slotted holes, c p For the longitudinal wave velocity of the rock mass, K c For rock fracture toughness, t For the tensile strength of rock, m The critical strain rate is denoted as .
3. The method for determining the optimal delay time for blasting cut holes in high-gas tunnels according to claim 1, characterized in that, The time required for rock mass movement during the stage of rock mass volume increase is calculated as follows: ， in: m To eject the rock mass, A For pressure bearing area, μ For the coefficient of friction, c For viscous damping coefficient, P 0 represents the initial pressure. V 0 represents the initial gas volume. A f For the equivalent area of the crack, v m For gas expansion rate, For gas density, d s For rock mass displacement, d t The time required for the rock mass displacement is given by D, where D is the detonation velocity of the explosive.
4. The method for determining the optimal delay time for blasting cut holes in high-gas tunnels according to claim 1, characterized in that, The time required for the rock mass movement during the rock mass ejection stage is calculated as follows: ， in: v 0 represents the initial launch velocity. For the launch angle, s 2 represents the size of the resistance line. α The angle of the slotted hole.
5. The method for determining the optimal delay time for blasting cut holes in high-gas tunnels according to claim 1, characterized in that, The specific method for constructing a three-dimensional model of the rock mass to be fractured in the slotted area is as follows: The scope of the three-dimensional model to be constructed is determined based on the on-site borehole layout data; A constitutive model of rock material was constructed based on rock mechanics parameters to create a three-dimensional model of the rock mass to be broken in the slotted area; the rock around the explosives, plugs and blast holes was modeled using SPH particle flow, and the remaining rocks were modeled using FEM finite element method. An explosive material model is constructed based on the explosive performance parameters, and the explosive charge in the slotted hole is calculated based on the slotted hole charging structure. A soil model is selected as the plugging method.
6. The method for determining the optimal delay time for blasting cut holes in high-gas tunnels according to claim 5, characterized in that, Post-processing is performed on the constructed 3D model of the rock mass to be broken in the slotted area. This includes setting the corresponding keywords for the SPH particle part and the FEM finite element part to eliminate the influence of boundary reflection waves. The total time required to eject the rock mass to be broken in the slotted area is used as the total model calculation time, and the interval of the rock mass migration simulation output file is set.
7. The method for determining the optimal delay time for blasting cut holes in high-gas tunnels according to claim 1, characterized in that, Specific monitoring points were selected at equal intervals along the vertical depth direction at the center of the three-dimensional model of the rock mass to be broken in the slotted area.
8. The method for determining the optimal delay time for blasting cut holes in high-gas tunnels according to claim 1, characterized in that, The rock mechanical parameters include rock density, shear modulus, longitudinal wave velocity, tensile strength, fracture toughness, and friction coefficient.
9. The method for determining the optimal delay time for blasting cut holes in high-gas tunnels according to claim 1, characterized in that, The explosive performance parameters include explosive density, detonation velocity, detonation pressure, initial specific internal energy, and initial relative volume.
10. A system for determining the optimal delay time of a blasting cut hole in a high-gas tunnel, implementing the method for determining the optimal delay time of a blasting cut hole as described in claim 1, characterized in that, include: The parameter acquisition module is used to conduct conventional mechanical tests on the surrounding rock area of the tunnel face, obtain the rock mechanical parameters of the surrounding rock of the tunnel face, and at the same time, statistically analyze the explosive performance parameters of the explosives used in the construction. The theoretical time calculation module is used to calculate the time required for rock mass movement during the rock mass crack propagation stage, rock mass volume increase stage, and rock mass ejection stage, respectively, based on rock mechanics parameters and explosive performance parameters, so as to obtain the time required for the rock mass to be broken to be completely ejected. The model building module is used to build a three-dimensional model of the rock mass to be broken in the slotted area and perform post-processing. The three-dimensional model of the rock mass to be broken in the slotted area includes blast holes, plugs, rock SPH particles and rock FEM finite element network. The monitoring and analysis module is used to select specific monitoring points along the vertical depth direction at the center of the three-dimensional model of the rock mass to be broken in the slotting area, and obtain the displacement and velocity time history curves of each monitoring point through numerical simulation; by analyzing the characteristics of the three stages of rock mass migration, the time node when the free face of the slotting area is completely formed is determined as the optimal delay time for the slotting hole. The delay time generation module is used to complete the overall model of the tunnel face based on the three-dimensional model of the rock mass in the cut area. It sets the delay time of the cut holes according to the optimal delay time of the cut holes, simulates the detonation of each row of blast holes in sequence, determines the optimal detonation delay time of each row of blast holes based on the rock mass ejection and the formation state of the free face in the numerical simulation, and ensures that the total delay time meets the total delay time specified for high-gas tunnels.