A method and system for calculating the radial uncoupling coefficient of a tunnel light blast hole under the action of hydrostatic stress

Abstract

This invention provides a method and system for calculating the radial decoupling coefficient of smooth blasting holes in tunnels under hydrostatic stress, belonging to the field of rock blasting engineering technology. The method involves measuring the original in-situ stress and rock mechanical parameters at the tunnel blasting site; measuring and labeling the relevant parameters of the explosives used in the project; establishing a smooth blasting stress analysis model based on the measurement data and design, and calculating the stress redistribution under hydrostatic stress; constructing a stress model based on the rock mechanical parameters and explosive parameters to analyze the stress state between holes; and analyzing the combined effect of radial compressive stress from stress redistribution and circumferential tensile stress from smooth blasting holes based on the conditions for fracture formation, thereby determining the radial decoupling coefficient of the smooth blasting holes. This invention ensures a reasonable design of the radial decoupling coefficient by quantifying the coupling effect of stress redistribution and explosive load, avoiding both insufficient blasting energy to generate fractures due to an excessively large coefficient and excessive damage to the surrounding rock or over-excavation due to an excessively small coefficient.

Description

Technical Field

[0001] This invention relates to the field of rock blasting engineering technology, and in particular to a method and system for calculating the radial decoupling coefficient of tunnel blasting holes under hydrostatic stress. Background Technology

[0002] Smooth blasting is a method of precisely controlling blasting parameters, utilizing the combined effects of stress wave superposition and explosive gas pressure to achieve controlled rock mass fracture. In tunnel blasting excavation, smooth blasting concentrates the explosive energy along the borehole connection direction by precisely controlling the detonation sequence and charge amount, forming a smooth and regular excavation face, minimizing disturbance and damage to the surrounding rock. The radial decoupling coefficient of a smooth blast hole refers to the ratio of the borehole diameter to the explosive cartridge diameter. In engineering, the radial decoupling coefficient is usually adjusted by changing the explosive cartridge diameter. A radial decoupling coefficient that is too low will damage the surrounding rock, while a coefficient that is too high will result in insufficient smooth blasting. Therefore, it is necessary to find the optimal decoupling coefficient to ensure the blasting effect.

[0003] The radial decoupling coefficient of smooth blasting boreholes is generally determined through empirical methods and field tests, which have poor adaptability to complex conditions. Empirical methods rely on similar engineering cases, which are poorly suited to geological conditions such as mixed rock, and also depend on the past experience of the staff, lacking a unified standard and making it difficult to guarantee the rationality of the parameters. Field tests, when determining the optimal radial decoupling coefficient, require setting up multiple sets of variable experiments due to numerous influencing factors, and controlling a single variable is difficult, time-consuming, and labor-intensive, increasing construction costs and timelines, and potentially delaying the progress of the main project.

[0004] While existing technologies have improved methods for determining the appropriate radial decoupling coefficient for smooth blasting holes, multiple simulations are still required to determine the optimal parameters. For example, patent CN202310957556 uses LS-DYNA finite element analysis software for simulation, requiring multiple simulations within a selected range of radial decoupling coefficients. The radial decoupling coefficient is changed using a bisection method, and the blasting effect diagram is compared to determine the optimal coefficient. This method is safe and reliable, but it requires multiple simulations to determine the optimal coefficient, consuming a significant amount of time. Furthermore, the results are unreliable due to factors such as calculation parameters and mesh size. CN121050251A and others use different algorithms to determine the optimal smooth blasting parameters, but this method requires continuous optimization and improvement of the parameters, which is also time-consuming.

[0005] Therefore, a method for calculating the radial decoupling coefficient of optical burst holes that can be quickly optimized and adjusted on-site is needed. Summary of the Invention

[0006] The purpose of this invention is to provide a method and system for calculating the radial decoupling coefficient of smooth blasting boreholes in tunnels under hydrostatic stress, thereby addressing the shortcomings of traditional methods in quickly and accurately determining the radial decoupling coefficient in practical engineering problems. This invention analyzes the combined effect of radial compressive stress generated by the stress redistribution in the smooth blasting layer under hydrostatic stress and circumferential tensile stress generated by the smooth blasting borehole explosion between the boreholes. Based on measured rock parameters, the conditions for joint formation between the boreholes are determined, and the radial decoupling coefficient of the smooth blasting borehole is calculated, ensuring more efficient and cost-effective smooth blasting engineering.

[0007] To achieve the above objectives, the technical solution adopted by the present invention is as follows: The first aspect of this invention provides a method for calculating the radial decoupling coefficient of a tunnel blast hole under hydrostatic stress, comprising the following steps: Step 1: Measure and record the original ground stress, rock mechanics parameters, and explosive performance parameters of the tunnel smooth blasting excavation project. Step 2: Establish a stress analysis model based on the measured original ground stress, the radius of the free face of the smooth blasting and the preset smooth blasting radius, and calculate the redistribution of ground stress; Step 3: Based on the rock material parameters and explosive material parameters, construct a stress model and analyze the stress state between the holes in the light blasting holes; Step 4: Based on the principle that the combined effect of the radial stress generated by the redistribution of ground stress and the circumferential tensile stress from blasting must be greater than the dynamic tensile strength of the rock in order to form a smooth and flat excavation face that penetrates the blast hole, a suitable radial decoupling coefficient for the blast hole is determined.

[0008] Preferably, step 1 specifically includes: The original in-situ stress of the tunnel surrounding rock was measured, and the measured original in-situ stress in the vertical direction was set as... P V The original horizontal stress is set as P H Material parameter calibration tests were conducted on rock samples from the tunnel to obtain the Poisson's ratio of the rock. m, Dynamic tensile strength of rock s tr Record the density of the explosives used. r e The detonation velocity of explosives D e Detonation isentropic index c Borehole wall pressure increase coefficient n .

[0009] Preferably, in step 1, for a hydrostatic stress field, its original stress P V = P HThen the lateral pressure coefficient λ= 1. Let P V = P H = P 0.

[0010] Preferably, in step S1, the original ground stress is determined by hydraulic fracturing or stress relief; the rock mechanical parameters are determined by uniaxial compression test or split Hopkinson bar test; and the explosive performance parameters are determined experimentally or obtained by consulting the explosive technical specifications.

[0011] Preferably, the preset smooth surface blasting radius in step 2 is [missing information]. r 0, the radius of the free face of the smooth blasting is r 1. The diameter of the blast hole is D The distance between two adjacent blast holes is 2. d ; The stress analysis model is a geometric model that includes light-blown holes, surrounding rock, and free face, and the model boundary is subjected to a geostress load corresponding to the original geostress.

[0012] Preferably, in step S3, the radial compressive stress of the geostress redistribution s r Calculated using formula (1): (1) in, s r It is radial compressive stress; The peak value of the explosive load generated on the borehole wall during radial uncoupled charge blasting in a light blasting hole is calculated using formula (2); (2) in, n It is the pressure enhancement coefficient. β It is the radial decoupling coefficient, which, according to the attenuation law of stress waves in rock, represents the circumferential tensile stress on the rock surrounding the decoupled charge blast hole. s θb The value should satisfy formula (3); (3) in, a It is the lateral stress coefficient. a = m b / ( 1 -m b ) In engineering blasting, take m b =0.8 m , mIt is the Poisson's ratio of the rock; α It is the attenuation coefficient; The comparison is based on distance. Because the flash blast holes detonate simultaneously, the circumferential tensile stress generated by the explosion at the midpoint between two adjacent flash blast holes reaches a peak, which is conducive to crack formation. d Let the distance from the charge center to the midpoint of two adjacent blast holes be denoted as and the distance from the charge center to the calculation point be denoted as . d Then the distance satisfies formula (4): (4)

[0013] Preferably, in step 3, the project employs a simultaneous blasting method. Based on the stress wave propagation law, the stress reaches its peak at the midpoint between two adjacent holes, at a distance of... d The distance from the midpoint of the line connecting adjacent optical detonation holes to the center of the optical detonation hole; attenuation coefficient α The radial decoupling coefficient is determined by the rock type and experimental measurements, and is used as a preset parameter for calculation and analysis.

[0014] Preferably, step 4 specifically includes, To create a smooth and flat excavation face through smooth blasting, the radial compressive stress of the ground stress redistribution, the circumferential tensile stress of the blasting, and the dynamic tensile strength of the rock should satisfy formula (5): (5) Combining the above formulas, we obtain formula (6), which is the radial decoupling coefficient of the radial optical burst hole. β Represented as: (6) The radial decoupling coefficient of the optical burst holes was calculated by incorporating field measurement data.

[0015] Preferably, in step 4, the coupling effect of the blasting circumferential tensile stress and the radial compressive stress of the ground stress redistribution is ensured according to the criterion formula (5) to overcome the dynamic tensile strength of the rock, thereby successfully forming a crack; the radial decoupling coefficient of the blast hole is calculated according to the formula (6) and verified.

[0016] Another aspect of the present invention provides a system for calculating the radial decoupling coefficient of tunnel blast holes under hydrostatic stress. The system is based on the aforementioned method for calculating the radial decoupling coefficient of tunnel blast holes under hydrostatic stress, and includes: The parameter acquisition module is used to measure and store the original geostress of the tunnel, rock mechanics parameters, and explosive performance parameters. The model building module is used to establish a smooth blasting stress analysis model based on the original ground stress and preset smooth blasting parameters. The stress analysis module is used to calculate the radial compressive stress and circumferential tensile stress of ground stress redistribution based on rock mechanics parameters, explosive performance parameters and stress analysis models. The coefficient calculation module is used to output the radial decoupling coefficient of the blast hole based on the balance relationship between the radial compressive stress of the ground stress redistribution, the circumferential tensile stress of blasting, and the dynamic tensile strength of the rock. The model verification module supports verifying the rationality of coefficients through on-site blasting tests or numerical simulations. If the half-pore ratio is lower than the preset threshold, the coefficient calculation results will be automatically optimized. The data storage module stores all parameter data, analysis results, and validation data, and supports export in Excel and PDF formats for easy project archiving.

[0017] The present invention has the following beneficial effects: 1. Overcoming the limitations of traditional empirical design, this invention offers an efficient calculation process and enables the scientific and quantitative determination of the radial decoupling coefficient of blast holes. Traditional methods rely on empirical formulas and field experiments, depending on the experience of personnel, lacking unified standards, and making it difficult to quickly determine a suitable radial decoupling coefficient. Determining the radial decoupling coefficient through field experiments involves numerous influencing factors, requiring extensive testing, which is time-consuming and labor-intensive. This invention establishes a dynamic coupling model between ground stress redistribution and blast stress waves, achieving theoretical calculation and quantitative design of the radial decoupling coefficient of blast holes, overcoming the difficulties of determining a suitable radial decoupling coefficient for blast holes in practical engineering using traditional methods.

[0018] 2. Significantly improves the reliability of crack formation between boreholes and the quality of excavation. By calculating the combined effect of radial compressive stress from ground stress redistribution and circumferential tensile stress generated by blasting, a suitable radial decoupling coefficient for smooth blasting holes is quickly determined, ensuring that smooth blasting can successfully form cracks. This avoids excessive damage to the surrounding rock or over-excavation caused by an excessively small radial decoupling coefficient, as well as insufficient blasting energy for crack formation between boreholes due to an excessively large coefficient.

[0019] 3. Previous methods for calculating the radial decoupling coefficient were affected by many factors. This invention is a theoretical calculation based on experimental measurement data, which yields a theoretical solution with high reliability.

[0020] The present invention has the following advantages: For the first time, this invention analyzes the radial compressive stress and circumferential tensile stress generated by blasting in smooth blasting of tunnels under still water stress, overcoming the limitations of traditional empirical design. A quantitative index system incorporating relevant parameters such as rock and explosives is established to ensure the scientific rigor of smooth blasting design and the reliability of results. The method is logically clear and the steps are well-defined. All required parameters can be obtained through field experiments, eliminating reliance on finite element analysis software and programming skills. It is easily mastered and applied by field engineers and has wide applicability in engineering projects under still water stress. By accurately determining the radial decoupling coefficient of the smooth blasting hole, the disturbance and damage to the surrounding rock can be minimized while ensuring blasting effectiveness, improving construction efficiency, and effectively controlling construction safety risks. Attached Figure Description

[0021] The present invention will be further described below with reference to the accompanying drawings and embodiments.

[0022] Figure 1 This is a design diagram of the arrangement of light blast holes under hydrostatic stress according to the present invention.

[0023] Figure 2 This is a simplified representation of the stress state between two adjacent light-burst holes in this invention.

[0024] Figure 3 This is a flowchart illustrating the implementation steps of the present invention.

[0025] Figure 4 This is a comparison chart of the semi-pore ratio of smooth blasting using the present invention and existing methods.

[0026] Legend: 1- Surrounding rock, 2- Smooth blasting face, 3- Smooth blasting hole, 4- Pre-designed smooth blasting excavation face, 5- Vertical ground stress P v 6-Horizontal ground stress P H 7-Radius of the free surface of a smooth blast r 1,8 - Preset excavation radius r 0,9 - Radial compressive stress of stress redistribution s r 10-Air, 11-Explosive, 12-Explosive circumferential tensile stress s θb . Detailed Implementation

[0027] To make the objectives, technical solutions, and advantages of this invention clearer, the embodiments of this invention will be described in detail below with reference to the examples. However, those skilled in the art will understand that the following examples are only for illustrating this invention and should not be regarded as limiting the scope of this invention.

[0028] Example 1: This embodiment provides a method for calculating the radial decoupling coefficient of tunnel blast holes based on hydrostatic stress, including the following steps: Step 1, Obtaining the original ground stress, rock parameters, and explosive parameters: In the tunnel blasting excavation area, the original ground stress was accurately measured using methods such as hydraulic fracturing, and the original ground stress in the vertical direction was measured. P v Horizontal original geostress P H Under hydrostatic stress, the measured original vertical stress is equal to the original horizontal stress, denoted as . P V=P H =P 0. The following parameters were collected experimentally in the laboratory: the Poisson's ratio of the rock was calculated by strain measurement in a uniaxial compression test. m The dynamic tensile strength of rock was obtained through a split Hopkinson bar test. s tr Explosive-related parameters can be found in experiments or in the technical specifications or blasting manuals based on the explosive type: Explosive density. r e The detonation velocity of explosives D e Detonation isentropic index c Borehole wall pressure increase coefficient n .

[0029] Step 2: Establish a stress analysis model for smooth blasting: Stress analysis is performed by constructing a model based on the actual blasting scheme. The geometric parameters of the model are determined according to the blasting scheme design, specifically including the preset smooth blast radius. r 0, the radius of the free face of the smooth blasting is r 1. The diameter of the blast hole is D The distance between two adjacent blast holes is 2. d Based on the above parameters, a stress analysis model for smooth blasting is established.

[0030] Step 3: Construct a stress model and analyze the stress state between two adjacent optical burst holes: Based on the original geostress measured in step 1, apply stress redistribution radial compressive stress to the model boundary. s r The calculation formula is: (1) The stress state between two adjacent open-holes is analyzed. The peak value of the blast load generated on the hole wall when the radially uncoupled charge of the open-hole explodes is calculated according to formula (2).

[0031] (2) in, n It is the pressure enhancement coefficient. β It is the radial decoupling coefficient.

[0032] Based on the attenuation law of stress waves in rock, the peak circumferential stress of the rock surrounding the uncoupled charge optical blast hole is... s θb According to formula (3): (3) in, It is the lateral stress coefficient. = m b / ( 1 -m b ) In engineering blasting, generally... m b =0.8 m , m It is the Poisson's ratio of rocks. It is the attenuation coefficient. The comparison is based on distance. Because the flash blast holes detonate simultaneously, the circumferential tensile stress generated by the explosion at the midpoint between two adjacent flash blast holes reaches a peak, which is conducive to crack formation. d Generally, the distance from the charge center to the midpoint between two adjacent flash blast holes is denoted as _____. The distance from the charge center to the calculation point is denoted as _____. d Then the distance satisfies formula (4).

[0033] (4) Step 4: Combining the stress field and the stress analysis between the optically flared holes, determine the radial decoupling coefficient of the optically flared holes: During smooth blasting, the area between two adjacent smooth blast holes experiences radial compressive stress due to stress redistribution. s r and the circumferential tensile stress generated by the explosion s θb Radial compressive stress inhibits the formation of cracks between holes, while circumferential tensile stress promotes crack formation. At the same time, there is also the dynamic tensile strength of the rock. Therefore, according to the crack formation criterion shown in formula (5), the formation of a smooth surface can only be ensured when the resultant force of circumferential tensile stress and radial compressive stress exceeds the dynamic tensile strength of the rock.

[0034] (5) Substituting the above formulas (1) to (4) into the criterion formula (5), a formula for calculating the radial decoupling coefficient can be derived, namely formula (6): (6) Substituting the design parameters, rock parameters, and explosive parameters obtained in step 1 into formula (6), the radial decoupling coefficient of the tunnel blast hole under static water stress can be obtained through calculation. β This coefficient is the scientific and reasonable radial decoupling coefficient determined in this invention. Based on this design, it is possible to avoid insufficient blasting energy and failure to form joints between holes due to an excessively large radial decoupling coefficient, and also to avoid excessive damage to the surrounding rock and over-excavation due to an excessively small radial decoupling coefficient.

[0035] Furthermore, the measurement of the original in-situ geostress and rock parameters in step 1 requires the use of specialized equipment and scientific methods to ensure accuracy.

[0036] Furthermore, in step 2, the radii of the free surface of the smooth blasting and the preset surface, as well as the diameter of the blast hole, are modeled according to actual parameters.

[0037] Furthermore, in step 3, the calculation of the peak blast load on the borehole wall during uncoupled charge blasting is based on the rock dynamics characteristics, the lateral stress coefficient is determined according to the rock Poisson's ratio, and the attenuation coefficient is determined according to the rock type and wave impedance.

[0038] Furthermore, in step 4, the smooth blasting holes are simultaneously blasted. Due to the superposition effect of stress waves, the peak value of the circumferential tensile stress is considered to ensure that the dynamic tensile strength of the rock is overcome. The radial decoupling coefficient of the smooth blasting holes is calculated according to formula (6), and then verified and optimized.

[0039] Example 2: The following is in conjunction with the embodiments and appendices Figure 1-4 The technical solution of the present invention will be described in detail, and the implementation process is as follows: Figure 3 As shown, this embodiment takes a smooth blasting test of a tunnel under static water stress as an example, but it does not constitute a limitation on the scope of protection of this invention.

[0040] Step 1: Measure the hydrostatic stress and rock parameters. Measure the original stress of the surrounding rock 1 at the site, including the vertical stress. P v The horizontal ground stress is 20 MPa. P H For example, 20MPa Figure 1 As shown; rock samples were calibrated by parameter determination to determine the Poisson's ratio. m The dynamic tensile strength of rock is 0.26. s tr The pressure is 20 MPa; the density of the explosive used is... r e 1000 kg / m 3 The detonation velocity of explosives D e The isentropic exponent of detonation is 3600 m / s. c The borehole wall pressure increase coefficient is 3. n It is 8.

[0041] Step 2, establish a stress analysis model for smooth blasting, such as... Figure 1 Preset smooth blasting excavation radius r 0 is 5.5m, radius of the free face for smooth blasting. r 1 is 5m, borehole diameter D The diameter is 42mm, and the borehole spacing is 2. d It is 0.5m.

[0042] Step 3, analyze the stress state between two adjacent light-burst holes as follows: Figure 2The light-burst layer is subjected to radial compressive stress 9 due to stress redistribution. The radial compressive stress due to stress redistribution can be calculated according to formula (1). s r size.

[0043] (1) Simultaneously, during blasting, the circumferential tensile stress 12 generated by the blasting will also act on the light blasting layer, working together with the radial compressive stress 9. The peak value of the blasting load generated during the radial decoupled charge explosion of the light blasting hole is calculated according to formula (2).

[0044] (2) in β This is the decoupling coefficient. Based on the attenuation law of stress waves in rock, it represents the peak circumferential stress experienced by the rock surrounding the uncoupled charge blast hole. s θb According to formula (3): (3) The distance is calculated using formula (4): (4) Step 4: Based on the comprehensive spatial stress analysis of smooth blasting, for smooth blasting to successfully form cracks between holes, the area between two adjacent smooth blasting holes is subjected to both radial compressive stress and circumferential tensile stress. The combined effect of the circumferential tensile stress and the radial compressive stress from the redistribution of ground stress must be greater than the dynamic tensile strength of the rock, satisfying formula (5).

[0045] (5) Therefore, the radial decoupling coefficient of the light-burst hole that satisfies the requirement of inter-hole tensioning and slit formation satisfies formula (6). (6) Step 5, optimize the calculation. Based on the formula (6) given in step 4, substitute the various relevant parameters obtained from the measurement to calculate the radial decoupling coefficient of the light-burst hole that satisfies the inter-hole slit condition as 1.26.

[0046] The radial decoupling coefficient obtained by the traditional method is 1.29. Considering the suppression effect of radial compressive stress during stress redistribution, this invention calculates a radial decoupling coefficient of 1.26. For example... Figure 4 As shown, compared with traditional methods, the radial decoupling coefficient calculated by this method can effectively improve the half-pore ratio. Furthermore, this method has a short calculation time of only 20 minutes, demonstrating high computational efficiency.

[0047] Example 3: This embodiment provides a system for calculating the radial decoupling coefficient of tunnel blast holes under hydrostatic stress. The system includes a parameter acquisition module, a model building module, a stress analysis module, a coefficient calculation module, a model verification module, and a data storage module. These modules work together to achieve automated calculation of the decoupling coefficient. Parameter acquisition module: includes a ground stress sensor, a rock parameter testing device and an explosive parameter input unit, used to accurately collect and store original ground stress, rock mechanical parameters and explosive performance parameters; Model building module: Based on the data from the parameter acquisition module, it automatically generates a stress analysis model that includes smooth blasting holes, surrounding rock, and free face, and supports custom input of preset smooth blasting parameters; Stress Analysis Module: Built-in stress calculation algorithm, automatically calls parameter data, calculates radial compressive stress and circumferential tensile stress through preset formulas, and outputs stress distribution cloud map; Coefficient Calculation Module: Based on the stress analysis results and the dynamic tensile strength of the rock, the radial decoupling coefficient is solved using the equilibrium relationship formula, and the calculation results are output. Model verification module: Supports verification of coefficient rationality through on-site blasting tests or numerical simulations. If the half-porosity is lower than a preset threshold (e.g., 85%), the coefficient calculation results are automatically optimized. Data storage module: Stores all parameter data, analysis results and validation data, and supports export in Excel and PDF formats for easy project archiving.

[0048] Furthermore, the parameter acquisition module includes a ground stress sensor, a rock parameter testing device, and an explosive parameter input unit; the ground stress sensor is used to collect hydrostatic stress data of the tunnel surrounding rock in real time, the rock parameter testing device is used to determine the Poisson's ratio and dynamic tensile strength of the rock, and the explosive parameter input unit is used to input performance parameters such as explosive density and detonation velocity.

[0049] Furthermore, the stress analysis module has a built-in stress calculation algorithm that can automatically call the parameters to obtain the data stored in the module, calculate the radial compressive stress and circumferential tensile stress through preset formulas, and output a stress distribution cloud map.

[0050] Although the preferred embodiments of the present invention have been described above in conjunction with the accompanying drawings, the present invention is not limited to the specific embodiments described above. The specific embodiments described above are merely illustrative and not restrictive. Those skilled in the art can make many specific modifications under the guidance of the present invention without departing from the spirit of the invention and the scope of protection of the claims, and these modifications all fall within the scope of protection of the present invention.

Claims

1. A method for calculating the radial decoupling coefficient of a tunnel blast hole under hydrostatic stress, characterized in that, Includes the following steps: Step 1: Measure and record the original ground stress, rock mechanics parameters, and explosive performance parameters of the tunnel smooth blasting excavation project. Step 2: Establish a stress analysis model based on the measured original ground stress, the radius of the free face of the smooth blasting and the preset smooth blasting radius, and calculate the redistribution of ground stress; Step 3: Based on the rock material parameters and explosive material parameters, construct a stress model and analyze the stress state between the holes in the light blasting holes; Step 4: Based on the principle that the combined effect of the radial stress generated by the redistribution of ground stress and the circumferential tensile stress from blasting must be greater than the dynamic tensile strength of the rock in order to form a smooth and flat excavation face that penetrates the blast hole, a suitable radial decoupling coefficient for the blast hole is determined.

2. The method for calculating the radial decoupling coefficient of a tunnel blast hole under hydrostatic stress as described in claim 1, characterized in that, Step 1 specifically includes: The original in-situ stress of the tunnel surrounding rock was measured, and the measured original in-situ stress in the vertical direction was set as... P V The original horizontal stress is set as P H Material parameter calibration tests were conducted on rock samples from the tunnel to obtain the Poisson's ratio of the rock. μ, Dynamic tensile strength of rock σ tr Record the density of the explosives used. ρ e The detonation velocity of explosives D e Detonation isentropic index γ Borehole wall pressure increase coefficient n .

3. The method for calculating the radial decoupling coefficient of a tunnel blast hole under hydrostatic stress as described in claim 2, characterized in that, In step 1, for the hydrostatic stress field, its original stress P V = P H Then the lateral pressure coefficient λ= 1. Let P V = P H = P 0.

4. The method for calculating the radial decoupling coefficient of a tunnel blast hole under hydrostatic stress as described in claim 2, characterized in that, In step S1, the original ground stress is determined by hydraulic fracturing or stress relief; the rock mechanical parameters are determined by uniaxial compression test or split Hopkinson bar test; and the explosive performance parameters are determined experimentally or obtained by referring to the explosive technical specifications.

5. The method for calculating the radial decoupling coefficient of a tunnel blast hole under hydrostatic stress as described in claim 3, characterized in that, In step 2, the preset smooth surface blast radius is... r 0, the radius of the free face of the smooth blasting is r 1. The diameter of the blast hole is D The distance between two adjacent blast holes is 2. d ; The stress analysis model is a geometric model that includes light-blown holes, surrounding rock, and free face, and the model boundary is subjected to a geostress load corresponding to the original geostress.

6. The method for calculating the radial decoupling coefficient of a tunnel blast hole under hydrostatic stress according to claim 5, characterized in that, In step S3, the radial compressive stress of the ground stress redistribution σ r Calculated using formula (1): （1） in, σ r It is radial compressive stress; The peak value of the explosive load generated on the borehole wall during radial uncoupled charge blasting in a light blasting hole is calculated using formula (2); （2） in, n It is the pressure enhancement coefficient. β It is the radial decoupling coefficient, which, according to the attenuation law of stress waves in rock, represents the circumferential tensile stress on the rock surrounding the decoupled charge blast hole. σ θb The value should satisfy formula (3); （3） in, It is the lateral stress coefficient. = μ b / ( 1 -μ b ) In engineering blasting, take μ b =0.8 μ , μ It is the Poisson's ratio of the rock; It is the attenuation coefficient; The comparison is based on distance. Because the flash blast holes detonate simultaneously, the circumferential tensile stress generated by the explosion at the midpoint between two adjacent flash blast holes reaches a peak, which is conducive to crack formation. d Let the distance from the charge center to the midpoint of two adjacent blast holes be denoted as and the distance from the charge center to the calculation point be denoted as . d Then the distance satisfies formula (4): （4）。 7. The method for calculating the radial decoupling coefficient of a tunnel blast hole under hydrostatic stress according to claim 6, characterized in that, In step 3, the project employs simultaneous blasting. Based on the stress wave propagation law, the stress reaches its peak at the midpoint between two adjacent holes, at a distance of... d The distance from the midpoint of the line connecting adjacent optical detonation holes to the center of the optical detonation hole; attenuation coefficient α The radial decoupling coefficient is determined by the rock type and experimental measurements, and is used as a preset parameter for calculation and analysis.

8. The method for calculating the radial decoupling coefficient of a tunnel blast hole under hydrostatic stress according to claim 6, characterized in that, Step 4 specifically includes, To create a smooth and flat excavation face through smooth blasting, the radial compressive stress of the ground stress redistribution, the circumferential tensile stress of the blasting, and the dynamic tensile strength of the rock should satisfy formula (5): （5） Combining the above formulas, we obtain formula (6), which is the radial decoupling coefficient of the radial optical burst hole. β Represented as: （6） The radial decoupling coefficient of the optical burst holes was calculated by incorporating field measurement data.

9. The method for calculating the radial decoupling coefficient of a tunnel blast hole under hydrostatic stress according to claim 8, characterized in that, In step 4, according to the criterion formula (5), the coupling effect of the blasting circumferential tensile stress and the radial compressive stress of the ground stress redistribution must overcome the dynamic tensile strength of the rock, so as to successfully form a crack; according to the formula (6), the radial decoupling coefficient of the blast hole is calculated and verified.

10. A system for calculating the radial decoupling coefficient of tunnel blast holes under hydrostatic stress, characterized in that, The system is based on any one of the methods for calculating the radial decoupling coefficient of tunnel smooth blast holes under hydrostatic stress as described in claims 1-9, including: The parameter acquisition module is used to measure and store the original geostress of the tunnel, rock mechanics parameters, and explosive performance parameters. The model building module is used to establish a smooth blasting stress analysis model based on the original ground stress and preset smooth blasting parameters. The stress analysis module is used to calculate the radial compressive stress and circumferential tensile stress of ground stress redistribution based on rock mechanics parameters, explosive performance parameters and stress analysis models. The coefficient calculation module is used to output the radial decoupling coefficient of the blast hole based on the balance relationship between the radial compressive stress of the ground stress redistribution, the circumferential tensile stress of blasting, and the dynamic tensile strength of the rock. The model verification module supports verifying the rationality of coefficients through on-site blasting tests or numerical simulations. If the half-pore ratio is lower than the preset threshold, the coefficient calculation results will be automatically optimized. The data storage module stores all parameter data, analysis results, and validation data, and supports export in Excel and PDF formats for easy project archiving.

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