A vibration isolation method and device for pre-splitting blasting based on crack aperture control

Abstract

This invention provides a pre-splitting blasting vibration isolation method and device based on crack opening control. The method includes determining the diameter of steel balls for the pre-splitting section of the surrounding rock in a deeply buried cavern based on characteristic parameters; drilling pre-splitting holes; binding explosive rolls to bamboo strips; uniformly attaching steel balls of different diameters to the outer periphery of the explosive rolls to form steel ball explosive rolls; placing the steel ball explosive rolls into the pre-splitting holes; and detonating the steel ball explosive rolls. This invention can accurately, timely, and effectively control the crack opening during pre-splitting blasting in high-stress rock masses, improving the crack formation effect while enhancing the pre-splitting vibration isolation effect, thus facilitating stable control of blasting excavation in deeply buried caverns.

Description

Technical Field

[0001] This invention belongs to the technical field of blasting excavation control in high-stress rock mass engineering, specifically relating to a pre-splitting blasting vibration isolation method and a pre-splitting blasting vibration isolation device based on crack opening control. Background Technology

[0002] In large-scale engineering projects such as hydropower, mining, petrochemicals, and transportation, there are often challenges related to the pre-splitting and fracture formation of semi-infinite rock masses under high stress conditions, as well as the safety control of vibration during subsequent excavation in the main blasting zone. The effectiveness of pre-splitting directly affects the safety and stability of the formed surrounding rock and the construction efficiency and safety of other structures under construction. In deep rock blasting excavation with high ground stress, pre-splitting is significantly affected by the clamping effect of ground stress, resulting in a smaller final crack opening and poor vibration isolation effect. To address these issues, especially for complex building structures with high requirements for vibration control (such as rock-anchored beam structures in hydropower projects), traditional pre-splitting blasting construction, including the deep-hole pre-splitting blasting technology promoted in recent years, focuses on macroscopic design adjustments (charge density, hole spacing, and degree of damage to surrounding rock). It lacks theoretical design and optimization regarding the formation process and principles of crack opening itself. The main methods used are increasing charge density or reducing hole spacing to ensure the length and width of the pre-splitting crack, but this also increases the vibration impact and the degree of damage to the surrounding rock. Furthermore, the dynamic impact of high ground stress on crack opening, particularly the tendency for crack opening to close, has not been clearly improved. All of these factors limit the further development and application of pre-splitting blasting.

[0003] In view of the above problems, it is of great practical significance to develop a pre-splitting blasting vibration isolation method that can both improve the crack aperture forming effect and control the clamping effect of high ground stress on pre-cracks. Summary of the Invention

[0004] To address the shortcomings of existing technologies, the purpose of this invention is to provide a pre-splitting blasting vibration isolation method and device based on crack opening control. This method can accurately, timely, and effectively control the crack opening of pre-splitting blasting in high-stress rock masses, improving the cracking effect while enhancing the pre-splitting vibration isolation effect, thus facilitating stable control of blasting excavation in deeply buried caverns.

[0005] To solve the above-mentioned technical problems, the technical solution adopted by the present invention is as follows:

[0006] A pre-splitting blasting vibration isolation method and device based on crack aperture control, comprising the following steps:

[0007] The diameter of the steel balls to be prepared for the pre-fractured section of the surrounding rock of the deep-buried cavern is determined based on the characteristic parameters of the pre-fractured section of the surrounding rock.

[0008] Drill pre-splitting holes, tie the explosive roll to the bamboo strip, and then evenly attach steel balls of different diameters to the outside of the explosive roll to form a steel ball explosive roll.

[0009] Place the steel ball explosive rolls into the pre-splitting holes and detonate them.

[0010] Furthermore, the specific method for determining the diameter of the steel ball is as follows:

[0011] Obtain the rock mechanics parameters and geostress conditions of the pre-fractured section of the surrounding rock of the deep-buried cavern;

[0012] Establish two-dimensional or three-dimensional numerical calculation models for single-hole or double-hole pre-splitting blasting to simulate the formation of fractures;

[0013] In the numerical calculation software, the numerical calculation model is processed and set according to the characteristic parameters of the pre-fractured section of the surrounding rock of the deep-buried cavern. The burst center distance of the crack is divided at equal intervals, the maximum opening value of the crack at different burst center distances is obtained, and the value of the maximum opening value is selected as the diameter for steel ball preparation.

[0014] Furthermore, the characteristic parameters of the pre-fractured tunnel section of the surrounding rock of the deep-buried cavern include rock mechanics parameters and geostress conditions;

[0015] The rock mass mechanical parameters are density, Poisson's ratio, elastic modulus, bulk modulus, shear modulus, tensile strength, compressive strength, damage coefficient, and strain rate coefficient.

[0016] The geostress conditions are the stress level and the lateral pressure coefficient.

[0017] Furthermore, a numerical calculation model was established using finite element software and solved by a solver. In post-processing, the normal displacement and normal stress time history of the rock mass elements on both sides of the crack were monitored to obtain the dynamic evolution process of the tensile crack aperture induced by pre-splitting blasting. Based on the dynamic evolution process of the tensile crack aperture, the aperture evolution law of the crack at different blast center distances under constrained conditions was obtained, and the aperture time history curve was obtained.

[0018] Furthermore, in the time history curves of crack aperture at different burst center distances, the crack aperture first increases to the highest point over time, then decreases to the lowest point, and finally gradually increases again. The value at the highest point is selected as the steel ball preparation diameter at different burst center distances of the crack.

[0019] Furthermore, steel balls were attached to the outside of the explosive cartridge using tape.

[0020] Furthermore, by drilling multiple pre-splitting holes and simultaneously detonating multiple steel ball explosive rolls in these holes, a networked blasting system is formed.

[0021] A pre-splitting blasting vibration isolation device based on crack aperture control, applied to any of the pre-splitting blasting vibration isolation methods based on crack aperture control, comprising:

[0022] Explosive rolls are placed inside pre-splitting holes to detonate and create cracks.

[0023] Multiple rows of steel balls of different diameters are evenly distributed within the loading depth range of the explosive roll within the pre-splitting hole.

[0024] Furthermore, in multiple rows of steel balls of different diameters, the steel balls are arranged sequentially from bottom to top in either order of increasing size or order of decreasing size.

[0025] Compared with the prior art, the present invention has the following advantages and beneficial effects:

[0026] This invention concretizes the crack propagation effects of blast shock waves, explosive gas pressure, and ground stress in traditional blasting crack formation theory, classifies the crack aperture change trends at different stages, and points out a method for determining the maximum crack aperture in high-stress rock masses. Simultaneously, based on the non-uniformity of crack aperture gradually decreasing with the distance from the blast center during crack propagation, high-strength steel particles of different diameters are prepared and attached to the outside of the explosive cartridge using adhesive tape. After the explosive is loaded and networked, after detonation, when the tensile stress exceeds the dynamic tensile strength of the rock, the rock cracks, forming radial cracks. Under the detonation action of the explosive, the steel particles are randomly squeezed into the radial cracks. As the explosive gas continues to push and the crack aperture continues to increase, the steel particles move into the crack. When the crack aperture is lower than the diameter of the steel particles, the steel particles come into contact with the rock mass on both sides of the crack and are squeezed and fixed, which also limits further reduction of the crack aperture, avoiding the subsequent high stress of the surrounding rock from squeezing and closing the crack, thus ensuring the pre-crack aperture and vibration isolation effect. Meanwhile, the presence of steel balls limits the influence of fracture closure on the propagation and action of explosive gases, promotes a high proportion of the explosive energy utilization at the fracture tip, and also increases the fracture propagation length. This invention can efficiently and accurately enhance the vibration isolation effect of pre-fractured joints in high-stress rock masses, and has broad application prospects. Attached Figure Description

[0027] The accompanying drawings, which are included to provide a further understanding of the invention and form part of this application, illustrate exemplary embodiments of the invention and are intended to explain the invention, but do not constitute an undue limitation thereof. In the drawings:

[0028] Figure 1 This is a flowchart of the pre-splitting blasting vibration isolation method based on crack aperture control according to the present invention.

[0029] Figure 2 This is a schematic diagram illustrating the effect of the steel ball of the present invention in inhibiting closure inside the crack.

[0030] Figure 3 This is the numerical calculation network model for pre-splitting blasting single-hole fracture formation in this invention.

[0031] Figure 4 This is a diagram illustrating the dynamic change curve of crack opening and the main functions of the present invention.

[0032] Figure 5 This is a top view of the binding of steel balls of different diameters on the outside of the drug roll of the present invention.

[0033] Figure 6 This is a side view of the binding of steel balls of different diameters on the outside of the drug roll of the present invention.

[0034] Among them, 1. pre-splitting hole; 2. explosive roll; 3. steel ball. Detailed Implementation

[0035] The technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention.

[0036] In the description of the present invention, it should be understood that the terms "center", "longitudinal", "lateral", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside" and the like indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as limiting the present invention. In addition, the terms "first", "second", etc. are only used for descriptive purposes and cannot be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Therefore, features defined as "first", "second", etc. may explicitly or implicitly include one or more of the features. In the description of the present invention, unless otherwise specified, "multiple" means two or more.

[0037] This invention provides a pre-splitting blasting vibration isolation method based on crack aperture control, such as... Figure 1 As shown, it includes the following steps:

[0038] Step 1: Determine the diameter of steel ball 3 for the pre-fractured section of the surrounding rock of the deep-buried cavern based on the characteristic parameters of the pre-fractured section.

[0039] Step 2: Drill pre-splitting holes 1, tie the explosive roll 2 to the bamboo strip, and then evenly attach steel balls 3 of different diameters to the outside of the explosive roll 2 to form a steel ball explosive roll.

[0040] Step 3: Place the steel ball explosive rolls into the pre-splitting holes 1 and detonate the steel ball explosive rolls.

[0041] In related technologies, the focus is on the macroscopic design adjustment of pre-splitting blasting (linear charge density, hole spacing, and degree of damage to surrounding rock). There is a lack of theoretical design and optimization in the formation process and principle of crack opening itself. The main method is to increase the linear charge density or reduce the hole spacing to ensure the length and width of the pre-splitting crack. However, this also increases the vibration impact and the degree of damage to the surrounding rock.

[0042] like Figure 2 As shown, this invention utilizes the dynamic influence of high ground stress on crack opening. Steel balls 3 are randomly squeezed into radial cracks under the action of explosive detonation, thereby fixing the steel balls 3 between two crack surfaces. This prevents the high-stress surrounding rock from squeezing and closing the cracks, reduces the vibration impact of the explosive roll 2 itself, and reduces the degree of damage to the remaining surrounding rock.

[0043] Meanwhile, the steel ball 3 used in this invention can withstand the explosion pressure and prevent it from being destroyed.

[0044] In this invention, such as Figure 2 As shown, considering the different proportions of the effects of blast shock wave, explosive gas pressure, and ground stress on crack propagation in traditional blasting crack formation theory, during the blasting process, the blast shock wave causes cracks to form around the pre-splitting hole 1, and the cracks increase in size over time. Then, due to the squeezing effect of ground stress on crack propagation, the cracks decrease in size over time. When explosive gas enters the crack, the explosive gas pressure causes the cracks to increase again. Therefore, the crack aperture time history curve exhibits the basic characteristics of "first increasing, then decreasing, then increasing again, and finally tending to equilibrium." Based on this characteristic, and taking into account the non-uniformity of crack aperture gradually decreasing with the distance from the blast center during crack propagation, this invention prepares high-strength steel balls 3 of different diameters and introduces them into the crack. The steel balls 3 contact the rock mass on both sides of the crack and are squeezed and fixed, which also limits the further reduction of crack aperture, avoiding the subsequent high stress of the surrounding rock from squeezing and closing the crack, thus ensuring the pre-crack aperture and vibration isolation effect.

[0045] Furthermore, for each pre-cracked hole 1, the crack gradually decreases as the distance between the bursting centers increases. Therefore, it is necessary to consider the diameter of the steel ball 3 prepared under different bursting center distances.

[0046] The specific method for determining the diameter of steel ball 3 is as follows:

[0047] Step 101: Obtain the rock mechanics parameters and geostress conditions of the pre-fractured section of the surrounding rock of the deep-buried cavern;

[0048] Step 102: Establish a two-dimensional or three-dimensional numerical calculation model for simulating pre-splitting blasting and fracture formation using single-hole or double-hole methods.

[0049] Step 103: In the numerical calculation software, the numerical calculation model is processed and set according to the characteristic parameters of the pre-fractured section of the surrounding rock of the deep-buried cavern. The positions of the bursting center of the crack are divided at equal intervals. The maximum opening value of the crack at different bursting center positions is obtained. The value of the maximum opening value is selected as the preparation diameter of steel ball 3.

[0050] This invention aims to capture the non-uniform characteristic of crack aperture gradually decreasing with the distance from the burst center during crack propagation, such as... Figure 3 As shown, based on the rock mechanics parameters and geostress conditions of the pre-fractured section of the deep-buried cavern surrounding rock, a two-dimensional or three-dimensional numerical calculation model for simulating pre-fracture blasting is established, either single-hole or double-hole. This model simulates the blasting of pre-fracture hole 1 and accurately obtains the maximum aperture value of the fracture at different blast center distances. This allows for the determination of the steel ball 3 preparation diameter at different blast center distances, ensuring that the corresponding steel ball 3 matches the maximum aperture value. The steel particles contact the rock mass on both sides of the fracture, are compressed and fixed, preventing the rock mass on both sides of the fracture from moving inward. Simultaneously, the presence of the steel ball 3 limits the influence of fracture closure on the propagation and action of the blasted gas, promotes a high proportion of blasted energy utilization at the fracture tip, and also increases the fracture propagation length.

[0051] Among them, a two-dimensional or three-dimensional numerical calculation model of a single or double hole for simulating pre-splitting blasting is established through a finite element model. Finite element software includes, but is not limited to, ANSYS or Abaqus.

[0052] Steel balls 3 of different diameters are attached to the outer periphery of the explosive cartridge. After the explosive is detonated, the magnitude of the detonation wave and the explosive gas is significantly higher than the magnitude of gravity. The high temperature and high pressure environment inside the hole causes the tape to break and melt. The steel balls 3 are basically horizontally squeezed into the rock repeatedly. The gravity effect of the steel balls 3 is weakened, which prevents the steel balls 3 from falling to the bottom of the hole quickly before being squeezed into the rock.

[0053] In this invention, in step 1, the characteristic parameters of the pre-fractured section of the surrounding rock of the deep-buried cavern include rock mechanics parameters and geostress conditions;

[0054] The rock mass mechanical parameters are density, Poisson's ratio, elastic modulus, bulk modulus, shear modulus, tensile strength, compressive strength, damage coefficient, and strain rate coefficient.

[0055] The geostress conditions are the stress level and the lateral pressure coefficient.

[0056] Specifically, in this invention, a numerical calculation model is established using finite element software and solved by a solver. In post-processing, the normal displacement and normal stress time history of the rock mass elements on both sides of the crack are monitored to obtain the dynamic evolution process of the tensile crack opening induced by pre-splitting blasting. Based on the dynamic evolution process of the tensile crack opening, the opening evolution law of the crack at different blast center distances under constraint conditions is obtained, and the opening time history curve is obtained.

[0057] In step 103, in the time history curve of the crack aperture at different burst center distances, the crack aperture first increases to the highest point over time, then decreases to the lowest point, and finally gradually increases. The value at the highest point is selected as the preparation diameter of steel ball 3 at different burst center distances of the crack.

[0058] In this invention, in order to allow the steel ball 3 to enter the crack with the blast shock wave or through the pressure of the explosive gas during blasting, the steel ball 3 is attached to the outside of the explosive roll 2 with tape, and the tape will melt during blasting.

[0059] In order to form a networked blasting by drilling multiple pre-splitting holes 1 and simultaneously detonating multiple steel ball explosive cartridges in multiple pre-splitting holes 1.

[0060] For example, by using the method provided by the present invention, a long crack is formed with fewer pre-splitting holes 1 than by conventional blasting methods, and the vibration impact of the explosive roll 2 itself and the degree of damage to the surrounding rock can be reduced.

[0061] In summary, this invention discloses a pre-splitting blasting vibration isolation method based on crack aperture control. This method considers the different proportions of the effects of blast shock wave, explosive gas pressure, and ground stress on crack propagation in traditional blasting fracture formation theory. Through numerical simulation and dynamic strain monitoring experiments, the trend of crack aperture variation in the near-zone of the blast crack under combined effects is analyzed. Based on the basic characteristics of the crack aperture time history curve—"first increases, then decreases, then increases again, and finally tends to equilibrium"—the maximum aperture value during crack evolution in medium-to-high stress rock masses is determined. Simultaneously, based on the non-uniformity of the aperture gradually decreasing with the distance from the blast center during crack propagation, high-strength materials of different diameters are prepared... High-strength steel pellets are attached to the outside of the explosive cartridge using adhesive tape. After the explosive is charged and networked, when the tensile stress exceeds the dynamic tensile strength of the rock after detonation, the rock cracks, forming radial fissures. The steel pellets are randomly squeezed into these radial fissures under the detonation force. As the explosive gas continues to propel the pellets and the fissure opening continues to increase, the steel pellets move further into the fissure. When the fissure opening is smaller than the diameter of the steel pellets, the pellets come into contact with the rock mass on both sides of the fissure and are compressed and fixed, thus limiting further reduction in the fissure opening and preventing subsequent high stress in the surrounding rock from closing the fissure. This ensures the pre-fissure opening and vibration isolation effect. Simultaneously, the presence of the steel pellets limits the impact of fissure closure on the propagation and action of the explosive gas, promoting a high proportion of the explosive energy utilized at the fissure tip and increasing the fissure propagation length. This invention can efficiently and accurately enhance the pre-fissure vibration isolation effect of high-stress rock masses, and has broad application prospects.

[0062] This invention also provides a pre-splitting blasting vibration isolation device based on crack aperture control, such as... Figure 5 and Figure 6 Shown, including:

[0063] Explosive roll 2 is used to be placed in pre-splitting hole 1 and detonated to form a crack;

[0064] Multiple rows of steel balls 3 of different diameters are evenly distributed within the loading depth range of the explosive roll 2 in the pre-splitting hole 1.

[0065] In order to allow the steel balls 3 to move into the crack due to the continuous push of the explosive gas and the continuous increase of the crack opening, the steel balls 3 of different diameters are arranged in order from bottom to top in either the order of smallest to largest or the order of largest to smallest.

[0066] It should be noted that, in the absence of conflict, the embodiments of the present invention and the features in the embodiments may be combined with each other.

[0067] The present invention will be further described below with reference to specific embodiments, but these are not intended to limit the scope of the invention.

[0068] Taking the pre-splitting process of an underground powerhouse as an example, this paper illustrates the process. The underground powerhouse is 300m deep with a ground stress of approximately 20MPa. During the excavation of the main powerhouse layer by layer, a combined construction method of deep-hole pre-splitting and small-step excavation was adopted. Specifically, before the step-by-step blasting excavation, a continuous fracture was first formed in the sidewall through pre-splitting blasting. During pre-splitting, it was necessary to ensure that a continuous fracture could be formed between the pre-splitting holes (1), and that its width was sufficient to effectively block the vibration propagation during the step-by-step blasting. In the specific pre-splitting blasting design, the pre-splitting hole (1) had a diameter of 76mm, a hole spacing of 0.7m, and a hole depth of 8.5m; rock emulsion explosives were used, with a cartridge diameter of 32mm and a linear density of 700g / m³. The step height for the small-step excavation was planned to be 3m, using vertical hole step-by-step blasting. To ensure the effectiveness of deep-hole pre-splitting under 20MPa stress and to reduce vibration during small-step blasting, this invention develops a pre-splitting blasting vibration isolation design method based on crack aperture control. This method controls and optimizes pre-splitting formation. (See...) Figure 1 The specific steps are as follows:

[0069] The present invention provides a method for pre-splitting and vibration isolation of high-stress rock mass based on crack aperture control, comprising the following steps:

[0070] Step 1: Determine the diameter of steel ball 3 for the pre-fractured section of the surrounding rock of the deep-buried cavern based on the characteristic parameters of the pre-fractured section, including:

[0071] ① Obtain the rock mechanics parameters and geostress conditions of the pre-fractured section of the surrounding rock of the deep-buried cavern, including rock mechanics parameters (density 2700kg / m3, elastic modulus 20GPa, Poisson's ratio 0.24 and corresponding pressure coefficients, damage parameters, etc.) and geostress conditions (approximately 20MPa).

[0072] ② Establish two-dimensional or three-dimensional numerical calculation models for single-hole or double-hole pre-splitting blasting, as shown in the attached figure. Figure 2 As shown;

[0073] ③ In the numerical calculation software, the numerical calculation model is processed and set according to the characteristic parameters of the pre-fractured section of the surrounding rock of the deep-buried cavern. The burst center distance of the crack is divided at equal intervals, the maximum opening value of the crack at different burst center distances is obtained, and the value of the maximum diameter opening value is selected as the preparation diameter of steel ball 3, as shown in the table below.

[0074] Table 1. Maximum (mean) fracture aperture at typical burst center distance.

[0075]

[0076] ⑤ By dividing the explosion center distance into equal intervals of 0.05m, different steel ball diameters suitable for opening control were selected. Referring to Table 1, steel balls with diameters of 0.06mm, 1mm, 2mm, 3mm, 5mm, 8mm, and 10mm were selected and prepared.

[0077] Step 2: Drill pre-splitting holes 1, tie the medicine roll to the bamboo strip, and then use tape to evenly attach steel balls 3 of different diameters to the outside of the medicine roll.

[0078] Step 3: Place the explosives into the hole, connect the wire mesh, and detonate.

[0079] Step 4: By monitoring the vibration impact of the main blast hole passing through the pre-crack, it was verified that steel balls 3 of different diameters played a role in inhibiting the reduction or even closure of crack opening in the pre-crack of high-stress rock mass. It was found that compared with conventional pre-crack blasting, steel balls 3 were squeezed into the crack, which achieved the restriction of crack closure in high-stress rock mass. During subsequent blasting of the main blast hole, the vibration of the rock mass on the other side of the pre-crack was smaller.

[0080] like Figure 4 As shown, the solid line is the conventional opening time history curve of the embodiment of the present invention, and the dashed line is the opening time history curve after the steel ball is embedded. It can be seen that the present invention can effectively improve the opening and increase the crack propagation length. It can efficiently and accurately enhance the pre-fracture and crack isolation effect of high-stress rock mass, and has broad application prospects.

[0081] This invention also provides a steel ball explosive roll, applied to any of the pre-splitting blasting vibration isolation methods based on crack aperture control, comprising:

[0082] Explosive roll 2 is used to be placed in pre-splitting hole 1 and detonated to form a crack;

[0083] Multiple rows of steel balls 3 of different diameters are evenly distributed within the loading depth range of the explosive roll 2 in the pre-splitting hole 1.

[0084] In each row of steel balls 3 of different diameters, the steel balls 3 are arranged in order from smallest to largest or from largest to smallest.

[0085] Obviously, those skilled in the art can make various modifications and variations to this invention without departing from its spirit and scope. Therefore, if these modifications and variations fall within the scope of the claims of this invention and their equivalents, this invention also intends to include these modifications and variations.

Claims

1. A pre-splitting blasting vibration isolation method based on crack aperture control, characterized in that, Includes the following steps: The diameter of the steel balls to be prepared for the pre-fractured section of the surrounding rock of the deep-buried cavern is determined based on the characteristic parameters of the pre-fractured section of the surrounding rock. Drill pre-splitting holes, tie the explosive roll to the bamboo strip, and then evenly attach steel balls of different diameters to the outside of the explosive roll to form a steel ball explosive roll. Place the steel ball explosive rolls into the pre-splitting holes and detonate the steel ball explosive rolls. The specific method for determining the diameter of the steel ball is as follows: Obtain the rock mechanics parameters and geostress conditions of the pre-fractured section of the surrounding rock of the deep-buried cavern; Establish two-dimensional or three-dimensional numerical calculation models for single-hole or double-hole pre-splitting blasting to simulate the formation of fractures; In the numerical calculation software, the numerical calculation model is processed and set according to the characteristic parameters of the pre-fractured section of the surrounding rock of the deep-buried cavern. The burst center distance of the crack is divided at equal intervals, the maximum opening value of the crack at different burst center distances is obtained, and the value of the maximum opening value is selected as the diameter for steel ball preparation.

2. The pre-splitting blasting vibration isolation method based on crack aperture control according to claim 1, characterized in that: The characteristic parameters of the surrounding rock of a deeply buried cavern with pre-fractured sections include rock mechanics parameters and geostress conditions. The rock mass mechanical parameters are density, Poisson's ratio, elastic modulus, bulk modulus, shear modulus, tensile strength, compressive strength, damage coefficient, and strain rate coefficient. The geostress conditions are the stress level and the lateral pressure coefficient.

3. The pre-splitting blasting vibration isolation method based on crack aperture control according to claim 1, characterized in that: A numerical calculation model was established using finite element software and solved by a solver. In post-processing, the normal displacement and normal stress time history of the rock mass elements on both sides of the crack were monitored to obtain the dynamic evolution process of the tensile crack aperture induced by pre-splitting blasting. Based on the dynamic evolution process of the tensile crack aperture, the aperture evolution law of the crack at different blast center distances under constraint conditions was obtained, and the aperture time history curve was obtained.

4. The pre-splitting blasting vibration isolation method based on crack aperture control according to claim 3, characterized in that: In the time history curves of crack aperture at different burst center distances, the crack aperture first increases to the highest point over time, then decreases to the lowest point, and finally gradually increases. The value at the highest point is selected as the steel ball preparation diameter at different burst center distances of the crack.

5. The pre-splitting blasting vibration isolation method based on crack aperture control according to claim 1, characterized in that: Steel balls are attached to the outside of the explosive cartridge using tape.

6. The pre-splitting blasting vibration isolation method based on crack aperture control according to claim 1, characterized in that: Networked blasting is achieved by drilling multiple pre-splitting holes and simultaneously detonating multiple steel ball explosive cartridges in these holes.

7. A pre-splitting blasting vibration isolation device based on crack aperture control, applied to the pre-splitting blasting vibration isolation method based on crack aperture control as described in any one of claims 1-6, characterized in that, include: Explosive rolls are placed inside pre-splitting holes to detonate and create cracks. Multiple rows of steel balls of different diameters are evenly distributed within the loading depth range of the explosive roll within the pre-splitting hole.

8. The pre-splitting blasting vibration isolation device based on crack aperture control according to claim 7, characterized in that: In a series of rows of steel balls of different diameters, the steel balls are arranged from bottom to top in either order of increasing size or order of decreasing size.

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