Study on Mechanism of Cumulative Directional Blasting of Brittle Karst Limestone in the Guizhou Province

Hu, Jie; Zhang, Yiping; Fang, Chengcheng; Miao, Yusong; Zhao, Xin; Liu, Dengguo

doi:https://doi.org/10.1155/2023/5039396

Advances in Materials Science and Engineering

On this page

Abstract Introduction Discussion Conclusions Data Availability Conflicts of Interest Acknowledgments References Copyright Related Articles

Research Article | Open Access

Volume 2023 | Article ID 5039396 | https://doi.org/10.1155/2023/5039396

Study on Mechanism of Cumulative Directional Blasting of Brittle Karst Limestone in the Guizhou Province

Jie Hu,¹Yiping Zhang,^1,2Chengcheng Fang,³Yusong Miao,⁴Xin Zhao,⁵and Dengguo Liu⁶

Academic Editor: José António Fonseca de Oliveira Correia

Received14 Jan 2023

Revised28 Feb 2023

Accepted17 Aug 2023

Published20 Sept 2023

Abstract

The theoretical analysis, mechanical test, numerical simulations, and model tests are carried out on the Taoziya tunnel in Guizhou to investigate the influence law of cumulative blasting technology on directional rock breaking and fracture propagation of brittle limestone. The penetration effect of the triangular-shaped charge cover angle on the metal jet, the expansion law of the main explosion crack, and the influence of the limestone directional damage effect are explored. The results show that high-energy metal jet is formed when the initial velocity of the shaped charge cover is lower than the sound velocity of the shaped charge cover material. The values of B1 and B2 of the original rock are 22.1 and 248.76, respectively, demonstrating the mechanical properties of high strength, high brittleness, and easy fracture. The evaluation index is brittle limestone, and the directional precracking effect of shaped charge blasting technology is remarkable. When the angle of the shaped charge cover is 90°, a penetrating crack is almost consistent with the direction of the precrack generated after the explosion. Moreover, the width of the slit is approximately 2 cm. The borehole imager scans show that the rock wall in the hole is smooth and stable, the test results are consistent with the simulation results, and the angle of the shaped charge cover is 90°. The results have certain guiding significance for rock blasting technology, surrounding rock control technology, and similar directional fracturing engineering in the karst area of Guizhou province.

1. Introduction

As a typical karst landform in the Guizhou province, the rock formations are mostly limestone and argillaceous limestone [1]. As resource exploitation moves to deep strata, limestone is characterized by complex rock properties such as high strength, high brittleness, and easy deformation during exploitation [2, 3]. The cumulative blasting technology can efficiently and directly fracture the rock mass, reduce the damage of the retained rock mass, and form a regular contour surface. Therefore, exploring the dynamic characteristics of limestone is of great importance for improving the application of cumulative blasting in actual projects such as tunnels, mines, and roads in the karst geology of the Guizhou province.

The application of cumulative blasting technology has been thoroughly investigated. Xiang and Rong [4] investigated karst limestone geology to analyze the influence of karst on stress propagation and optimized blasting technology to reduce blasting vibration by 20%. Dhekne et al. [5, 6] explored the blasting vibration mechanism of limestone under a blasting load based on the characteristics of explosives. The authors concluded that SME explosives are more suitable for limestone mines than ANFO explosives, effectively solving the stability problem of surrounding rock under mining disturbance. Liu et al. [7] improved and perfected the presplitting blasting technology with two test methods: groove-shaped energy and shaped charge coil presplitting blasting. Hu et al. [8, 9] established the rock failure criterion and analyzed the propagation law of vibration wave in Guizhou tunnel blasting engineering based on numerical simulation software. The results show that the peak value of vibration wave in the direction of energy accumulation is significant. Wu et al. [10, 11] studied the response law of blasting stress by the drilling and blasting method and improved blasting parameters and effectively decompressed rock’s compressive stresses according to directional rock-breaking technology. Kang et al. [12, 13] explored the influence of the material, shape, and angle of the shaped charge cover on the penetration effect. Lastly, the authors provided new ideas for improving the jet velocity through the presplitting blasting effect.

In addition, many researchers have investigated the mechanical properties and rock mass damage mechanism of limestone and brittle rocks. Fang et al. [14, 15] conducted Brazilian splitting experiments on limestone blocks and concluded that the permeability of fracture surface is sensitive and that damage stress-strain was affected by different temperatures. Tian [16] improved the RHT constitutive model, used ANSYS/LS-DYNA to simulate the difference of rock failure modes before and after the correction of constitutive parameters, and obtained the variation law of limestone failure strength and brittle material strength under explosive impact. Al-Swaidani et al. [17, 18] explored the mechanical properties of limestone under different impact loads, providing an effective reference for tunnel mining and disaster prevention. He et al. [19] found the precursor index of rock bursts based on the law of energy evolution and acoustic emission of limestone, providing a reference for identifying rock bursts. Li et al. [20–22] studied the change of brittle fracture of rock under a rock burst of low strength brittle material by means of a laboratory test and similar simulation and proposed a new strength range assessment method. In summary, many researchers have conducted in-depth studies on the influence mechanism of shaped charge parameters on the effect of presplitting blasting and the mechanical properties of limestone under load. However, the rock properties affect the excavation project due to the special terrain and complex rock strata in the Guizhou province. Hence, an energy-gathering blasting technology scheme for specific karst landforms is urgently required to analyze the rock blasting effect and the crack propagation law.

Therefore, the theoretical analysis, mechanical test, numerical simulation, and model test are employed in this paper to analyze the mechanical properties of the karst limestone in the Guizhou province. Moreover, the directional fracturing effect of cumulative blasting on brittle limestone is investigated, and penetration characteristics of metal jets are explored according to the parameters of shaped charge cover and the propagation law of rock fractures. The influencing mechanism of the penetration effect of charged blasting the brittle limestone is discussed. The research results are of great significance to rock excavation technology, surrounding rock control technology, and similar directional fracturing engineering practices in karst areas of the Guizhou province.

2. Theoretical Research on Directional Fracture Caused by Cumulative Blasting

2.1. The Principle of Rock Blasting

Directional cumulative blasting refers to changing the structure, shape, and material of the ordinary explosive column, reserving the concavity at the parallel symmetrical position of the charge column, and setting up a specially shaped metal cover. Directional cumulative blasting uses instantaneous energy to fracture the rock mass etc. [23, 24]. The directional damage principle of cumulative blasting is shown in Figure 1.

Shock waves and explosive gas are generated after the explosive is detonated. The resulting energy propagates through detonation waves along the energy-gathering direction. The shaped charge cover stabilizes and accumulates detonation waves, controlling the distribution of the explosion stress field and the quasistatic and wedge effects of detonation gas in the medium. According to the blasting void effect, detonation products are accumulated along the concavity axis, generating a metal jet with ultrahigh pressure and density. Finally, the rock medium is broken to achieve the purpose of directional rock breaking. In the non-energy-gathering direction, the blasting energy acts on the hole wall after the double weakening the charge column and the air. Hence, the damage to the surrounding rock of the hole wall is weakened. Therefore, the cumulative blasting technology improves the crack propagation ability in the presplit direction and weakens the crack evolution ability in the non-pre-split direction.

2.2. Analysis of the Penetration Effect of the Metal Jet

The high-speed moving jet and the low-speed moving pestle are produced after the initiation of the shaped charge column. The high-energy metal jet contacts the rock mass to form a penetration effect. The penetration process is divided into three stages: the opening stage, the quasisteady stage, and the termination stage [25, 26]. At this time, both the target plate and the jet are incompressible fluids, and jet penetration can be expressed aswhere P is the penetration depth, is jet density, and is rock density.

Pack and Evans improved the equation to calculate the fracture jet as follows:where λ is a constant (λ = 1-2) equal to λ = 1 for the continuous jet and λ = 2 for the broken jet. Therefore, equation (1) can be rewritten aswhere L is the jet’s total length.

A dimensionless parameter corrected equation can be employed, where Y is the yield strength of the target plate:

DiPersion proposed the following three penetration formulas based on Allision and Vitali’s virtual source theory [27]:

If the jet fractures after penetration, then

If the jet fractures during penetration, then

If the jet breaks before the penetration starts, then

The penetration formula is based on an empirical equation, considering the formation of the metal jet from velocity, shape, and target properties. The shaped charge cover affects the binding stress of the metal jet breaking through the barrier. It is concluded that the volume sound velocity (C) of the shaped charge material is higher than the collision velocity (crushing velocity V0), which is the necessary condition for forming the high-energy condensed metal jet. According to the detonation rock-breaking mechanism and incompressible fluid theory [28], the influence factors of cumulative blasting are the material, angle, stand-off, cover thickness, and loading density. The theoretical analysis results provide an important basis for selecting the parameters of the shaped cover, establishing the numerical simulation, and optimizing the penetration effect of the metal jet. Based on previous studies, the influence mechanism of the shaped charge cover angle on the blasting effect will be further investigated in this paper. The stereogram of the shaped charge jet is shown in Figure 2.

3. Model Test Similarity Analysis

3.1. Lithology Analysis of the Guizhou Province Karst Area

An example of the blasting project is the Taoziya tunnel, located in Zunyi City, Guizhou Province, China, 80 km from the county. The tunnel site is folded from north to east, and the rock fracture is complex. The elevation is 377.0 m–1596.8 m, and the elevation of the tunnel axis is 555.1 m–1581.6 m, belonging to the dissolution-tectonic mountain landform type. Since the tunnel site is close to the expressway and residential areas, higher requirements are provided for the blasting vibration, fly rocks, slope stability, and integrity after blasting.

Many complex structures exist, such as concealed faults, folds, and karst. The rock stratum mainly comprises limestone, argillaceous limestone, and dolomite. The surrounding brittle rock has high strength and brittleness and can easily rupture. The rock strata in different fault zones are significantly affected by excavation. The lithology distribution table of the Taoziya tunnel is shown in Table 1.

3.2. Mechanical Properties Analysis

The bulk rock in the middle of the tunnel ZK58 + 560 ∼ ZK58 + 580 was used as the original rock sample. Rock samples were prepared according to the International Society for Rock Mechanics (ISRM) standards and regulations. Then, uniaxial compressive tests (USC) and Brazilian mechanics tests were conducted. The Brazilian test employed the disk-shaped sample with a diameter of 50 mm and a thickness of 25 mm, while the UCS test used the cylindrical specimen with a diameter of 50 mm and a height of 100 mm. The mechanical test is shown in Figure 3.

Three groups of UCS and Brazilian tests were tested to ensure the objectivity of the experimental results. The mechanical characteristic curve is shown in Figure 4. The test results are converted via formula to obtain the main mechanical properties of rock samples, as shown in Tables 2 and 3.

(a)

(b)

The rock block demonstrated brittle characteristics and high strength and was prone to fracture in the mechanical test. Moreover, the surrounding rock was subjected to joint damage. Brittleness is a characteristic of the rock mass that causes rock fracture when subjected to small deformation [3], reflecting the deformation and fracture characteristics of the rock under load. Rock brittleness is related to mineral composition, Young’s modulus, Poisson’s ratio, pore fluid, tensile strength, compressive strength, internal friction angle, and P-S wave velocity [29]. According to the brittleness evaluation formula proposed by HUCKA and DAS [30], the brittleness characteristics of rock are positively correlated with B₁, B₂, and B₃. Zhang et al. [31, 32] demonstrated that Jinping marble, Baihetan cryptocrystalline basalt, and amygdaloid basalt are brittle rocks. In practical projects, B1 is often used as the evaluation index of brittleness. Based on the mechanical parameters’ analysis of limestone in the Taoziya tunnel, B₁ equals 22.1, which is higher than the B₁ value of the three types of rocks. Therefore, the limestone ore in this experiment is a typical brittle rock whose brittleness index is shown in Table 4.where and are uniaxial compressive strength and tensile strength, respectively, and φ is the rock’s internal friction angle.

3.3. Model Test Parameters of Cumulative Blasting

The effect of cumulative blasting is affected by the physical and mechanical properties of the blasting rock mass and the external factors, such as blasting device material and the charge structure. The test parameters obtained by preparing rock samples according to the blasting similarity criterion and dimensional analysis method (referring to the “Ordinary Concrete Mix Proportion Design Regulations”) are shown in Table 5.

4. Numerical Simulation Based on ANSYS/LS-DYNA

According to the research foundation in [33, 34], the shape of the shaped charge cover significantly affects the presplitting blasting effect. Common types include triangle, arc, and flat top, among which the metal jet peak difference of triangular shape charge cover is the largest, and the penetration effect is the best. Therefore, the penetration effect of different angles of triangle-shaped cover on brittle rock via numerical simulations is used to obtain the best angle.

4.1. LS-DYAN Algorithm Selection

LS-DYNA provides Lagrange, Euler, and ALE algorithms. The mesh was also severely deformed due to the severe deformation of the material during the simulated blasting process. ALE can effectively track the material structure when dealing with the boundary problem of grid motion, therefore not affecting the simulation results [35]. Hence, the ALE algorithm is chosen in this paper to perform computational analysis on large deformation problems.

4.2. Modeling and Meshing

4.2.1. Model Selection

The concrete: MAT_JOHNSON_HOLMQUIST_CONCRETE, HJC [36, 37]. Citing the MAT_ADD_EROSION failure criterion [38, 39], the equivalent yield strength equation iswhere D is the damage amount; εσ is the infinite strain rate; A, B, N, and c are the determined parameters.

The explosive: MAT_HIGH_EXPLOSIVE_BURN explosive model; the relationship between the detonation product and volume is expressed by the JWL equation of state:where is the relative volume, ρ0 is the initial internal energy, and A, B, R₁, and R₂ are the determined material parameters.

The copper is defined using the MAT _ JOHNSON _ COOK keyword:where A, B, C, n, and m are constants.

The air: MAT_NULL material model, equation of state EOS_LINEAR_POLYNOMIAL:where E is the ratio of internal energy to initial volume and C is a constant.

The calculation parameters are obtained according to the model material and equation [40], as shown in Table 6. Rock parameters are based on the mechanical analysis results.

4.2.2. Establishment and Mesh Division

The brittle rock mass model consisting of air, concrete, explosives, and copper is built. Semimodeling was adopted, and the boundary was set as a free boundary according to the model’s symmetry. The mapped mesh was used for cell partitioning since meshing impacts computational accuracy and time. According to the model of high-quality partition results, the node and the cell are set to162396 and 80320, respectively [41]. The peak pressure increased by 4% by doubling the number of grids to 160640 and selecting the same position (90°) for the shaped charge cover vertex. All angle models were meshed with this grid for efficient simulation, as shown in Figure 5.

4.3. Analysis of the Penetration Effect of the Triangle’s Different Angles

The pressure cloud diagram is established by employing different angles of 30°, 60°, 90°, and 120° and shaped charge roll models, as shown in Figure 6. The effect of the metal jet of a shaped charge cover penetrating rock block at different angles was simulated to analyze the optimal angle of the penetration effect, as shown in Figure 7.

(a)

(b)

(c)

(d)

(a)

(b)

(c)

(d)

According to Figure 6, the pressure distribution of the triangle-shaped cover diffuses from the center of the cover to the surrounding. Moreover, the pressure distribution varies with the change in the angle. When the angle is 30°, the pressure is concentrated in the middle of the cover. The included angle is small at this time, limiting the pressure conduction. At 60° and 120°, the pressure is distributed in the upper and middle parts of the cover. However, the pressure characteristics are not obvious since the high-pressure area is small. At 90°, the pressure is closest to the apex, and the high-pressure cloud is the most obvious. According to the final penetration effect shown in Figure 7, the penetration depth gradually deepens when the angle increases from 30° to 90°. However, when the angle reaches 120°, the penetration depth decreases. Energy transmission is blocked, and penetration ends. Finally, according to the pressure distribution, the peak value of the vertex, and the final penetration effect, the angle of the triangle-shaped cover is obtained as 90°. Therefore, a strong penetration effect can be observed on the brittle rock mass.

5. Directional-Shaped Charge Blasting

5.1. Test Scheme

The test is divided into two parts. The first part is the comparative test of ordinary charge and shaped charge blasting. The second part is the blasting test of the triangular cumulative cover at different angles. Blasting test parameters are shown in Table 7. Different angle-shaped charge cover structures were made. PVC was used for the charge tube, and copper was used as the material for the shaped charge cover. The model test block of 1 m × 1 m × 0.5 m was prepared according to the similarity criterion. The dynamic video of the hole and the high-definition crack trajectory map of the entire hole wall were obtained by the in-hole imager, as shown in Figure 8.

(a)

(b)

5.2. Analysis of Blasting Results at Different Angles of the Triangle

The comparative blasting test of the ordinary and shaped charges was designed according to the test scheme. The damage to the rock wall in the hole was observed by the borehole imager to verify the effectiveness of directional control blasting with a shaped charge. The contrast test is shown in Figure 9. Then, the triangular cumulative blasting test with different angles was carried out to obtain the optimal angle of directional rock breaking, as shown in Figure 10.

(a)

(b)

(a)

(b)

(c)

(d)

According to Figure 9, the three main cracks were produced after the explosion of the common test block, which was fan-shaped with an angle of approximately 120°. Moreover, the damage degree of the rock mass was disordered, and the rock block collapsed. The borehole imager was used to observe the powder phenomenon and the rock wall collapse within the hole. The main crack was formed after blasting the cover of the test block with a shaped charge. The crack extended from the blast hole to the direction of energy accumulation. The crack width was smaller than the width of an ordinary charge, the surface was relatively complete, and there was no large rock block collapse. The borehole imager observed subtle cracks in the hole’s wall, while the hole’s wall was relatively smooth and stable.

According to Figure 10, three irregular cracks can be observed after the 30° shaped charge cover explosion, with no complete through cracks. After the explosion of 60° and 120° shaped charge covers, the main crack produced secondary cracks in the direction perpendicular to the gathering energy and punching in the borehole. Among them, there was a crack orientation deviation of roughly 30° when the angle was 120°. A complete penetrating crack was formed after the explosion of the 90°-shaped charge cover, and the direction of the crack was almost the same as that of the precrack. The crack width was uniform for approximately 2 cm, and there was no secondary crack damage. The surrounding rock was relatively stable, and the presplitting effect was the best.

6. Discussion

According to the numerical simulation results, when t = 4.49 ms in the pressure cloud, the direction of the shock wave was the same as that of the presplitting. Furthermore, the high-pressure area was located at the tip of the shaped charge cover, and the energy propagated from the inside to the outside. When the angle was 30°–90°, the pressure was proportional to the angle increment. At 90°, the blasting energy distribution was guided due to the special angle of the charge, and the detonation product aggregation achieved the best stress concentration. According to Figure 7, the penetration process was completed within t = 80 ms–100 ms, and a 90° penetration depth was the deepest. This is because the angle affects the penetration depth, and the metal jet releases the maximum energy when the main body is in the largest contact with the target. The pressure on the apex of each shape charge cover is selected to obtain the pressure curve and analyze the pressure on the shaped charge cover with different angles at the moment of explosion, as shown in Figure 11. The peak pressure of 30° was nearly 44 MPa. When the angle increased to 60°, the peak pressure was 46 MPa. When the angle increased to 90°, the peak pressure was 59 MPa. When the angle increased to 120°, the peak pressure increased to 66 MPa. The result showed that the peak surface pressure increased with the included angle within the characteristic unit interval and time value. Consequently, the initial velocity of the metal jet increases as well.

According to the analysis of model test results, the common charge explosives detonated gas without restraint, and the explosive energy irregularly diffused around the hole wall. The instantaneous high-pressure destructive force far exceeded the compressive strength limit of the rock mass. Hence, the brittle rock mass was more vulnerable to structural damage than the ordinary rock mass, resulting in rock wall damage and uneven and irregular cracks. According to the contrast test, it was effectively verified that the shaped charge cover accumulated blasting energy in the precracking direction, reduced the destruction strength in the non-pre-cracking direction, and achieved the effect of directional rock breaking and surrounding rock protection.

According to the actual blasting effect of the shaped charge (Figure 10), the high-speed and high-pressure explosive gas produced by the explosion caused different degrees of rock damage, while cracks appeared in the energy accumulation direction. The metal jet of the 30°-shaped charge cover was greatly constrained, and the penetration effect on the target was limited. This observation shows that controlling the penetration energy of the metal jet is difficult when penetrating brittle rock masses of 60° and 120°. Consequently, the rock wall in the non-energy-gathering direction suffered joint damage, lowering the protective effect of the surrounding rock. A 90°-shaped charge cover can improve the metal jet’s stability and toughness, control the blasting energy’s direction, effectively inhibit the expansion range of the metal jet penetrating the brittle rock mass, and reduce the associated damage to the surrounding rock. In conclusion, when the angle of the triangle-shaped charge cover is 90°, the crack was flat, the strike was consistent, the surrounding rock was stable, and the directional rock breaking effect was obvious. Thus, the test results were consistent with the simulation results, and 90° was the best angle.

7. Conclusions

In this paper, to study the directional rock-breaking effect of cumulative blasting in brittle limestone, the Taoziya tunnel in Guizhou was taken as the engineering background to conduct mechanical tests, numerical simulation, and model tests and compare the blasting effects of different angles of the triangular shaped energy cover. The test has led to the following conclusions:(1)The influence mechanism between the shaped charge’s penetration depth and the metal jet’s initial velocity, shape, and target properties was theoretically analyzed. The metal jet penetration was formed when the initial velocity V0 of the cover was crushed and less than the volume sound C of the cover’s material. The experimental study was presented on the directional precracking brittle rock by metal jet in cumulative blasting.(2)The mechanical properties of the Taoziya Project rock were obtained through mechanical tests, introducing HUCKA and DAS brittleness evaluation formulas. The values of the evaluation index for brittle limestones B₁ and B₂ were obtained as 22.1 and 248.76, respectively, demonstrating high strength, high brittleness, and easy rupture. The evaluation index was determined as the brittle limestone, providing an important basis for selecting similar parameters and determining numerical simulation and model test schemes.(3)According to the comprehensive analysis of the numerical simulation results, the explosive gas generated by the shaped charge cover expanded in the direction of the shaped energy guided by the shaped charge tube, resulting in a directional penetration effect. At 90°, the pressure cloud map had the largest range, the vertex pressure curve was the highest, and the actual penetration was the deepest. Therefore, 90° was the best simulation angle.(4)The feasibility verification test of directional blasting of the shaped charge cover was carried out by the borehole imager. Compared with the ordinary charge, the shaped charge contained metal-shaped charge covers. Moreover, the metal jet expanded directionally to penetrate the hole wall, directly fracturing the rock and protecting the surrounding rock in the brittle rock mass.(5)According to the field model test, when the angle increased from 30° to 120°, the effective contact area and the length of the bottom edge of the shaped charge cover increased by 93.2%. Consequently, the metal jet’s initial velocity and penetration width increased with the effective contact area. According to the test results, the optimal angle of the triangle-shaped charge cover was 90° and the results were consistent with the theoretical analysis and numerical simulation results. The results are significant for rock excavation, surrounding rock control technology, and similar directional fracturing engineering practices in the karst area.

Data Availability

The data used to support the findings of this study are included within the article.

Conflicts of Interest

The authors declare that they have no conflicts of interest.

Acknowledgments

This study was supported by the National Natural Science Foundation of China (Mechanism of directional rock fragmentation by coupling effect of explosive energy: 5264004).

References

Y. Tie, “Research on engineering geology of coal resources exploration stage in Guizhou Province,” Inner Mongolia Coal Economy, vol. 8, pp. 101–103, 2014.
View at: Google Scholar
J. Chen, Q. Wang, J. Guo et al., “Mechanical properties and acoustic emission characteristics of karst limestone under uniaxial compression,” Advances in Materials Science and Engineering, vol. 2018, Article ID 2404256, 14 pages, 2018.
View at: Publisher Site | Google Scholar
X. Lv, Y. Yang, Y. Chen et al., “Experimental study on the relationship between compression stability and deformation localization of viscous/brittle rock-like materials,” Advances in Materials Science and Engineering, vol. 2021, Article ID 7153661, 11 pages, 2021.
View at: Publisher Site | Google Scholar
R. Xiang and Z. Rong, “Study on blasting safety technology applied in karst lime stone mine,” Procedia Engineering, vol. 84, pp. 873–878, 2014.
View at: Publisher Site | Google Scholar
P. Y. Dhekne, V. Balakrishnan, and R. K. Jade, “Effect of type of explosive and blast hole diameter on boulder count in lime ston-e quarry blasting,” Geotechnical and Geological Engineering, vol. 38, no. 4, pp. 4091–4097, 2020.
View at: Publisher Site | Google Scholar
X. Yue, M. Tu, Y. Li, G. Chang, and C. Li, “Stability and cementation of the surrounding rock in roof-cutting and pressure-relief entry under mining influence,” Energies, vol. 15, no. 3, p. 951, 2022.
View at: Publisher Site | Google Scholar
D. Liu, D. Wen, and J. Tong, “Cumulative charge presplit blasting technology,” Blasting, vol. 1, pp. 92–96, 2000.
View at: Google Scholar
R. Hu, Z. Zhu, J. Xie, and D. Xiao, “Numerical study on crack propagation by using softening model under blasting,” Advances in Materials Science and Engineering, vol. 2015, Article ID 108580, 9 pages, 2015.
View at: Publisher Site | Google Scholar
D. Guo, W. Xiao, D. Guo, and Y. Lu, “Numerical simulation of surface vibration propagation in tunnel blasting,” Mathematical Problems in Engineering, vol. 2022, Article ID 3748802, 10 pages, 2022.
View at: Publisher Site | Google Scholar
B. Wu, Y. Cui, G. Meng et al., “Research on dynamic response of shallow buried tunnel lining constructed by drilling and blasting method,” Advances in Materials Science and Engineering, vol. 2022, Article ID 4254690, 11 pages, 2022.
View at: Publisher Site | Google Scholar
F. Cao, S. Zhang, and T. Ling, “Blasting-induced vibration response of the transition section in a branching-out tunnel and vibration control measures,” Advances in Civil Engineering, vol. 2020, Article ID 6149452, 11 pages, 2020.
View at: Publisher Site | Google Scholar
Y. Kang, J. Jiang, and S. Wang, “Experimental and numerical simulation of multi-layer media penetration by shaped charge with different cover materials,” Chinese Journal of High Pressure Physics, vol. 26, no. 5, pp. 487–493, 2012.
View at: Google Scholar
F. Zhou, F. Zhan, and Y. Wu, “Damage effect of contact explosion in different shaped charge shells,” Engineering blasting, vol. 20, no. 1, pp. 9–12, 2014.
View at: Google Scholar
H. Fang, D. Xing, J. Yang, F. Liu, J. Chen, and J. Li, “Experimental study on limestone cohesive particle model and crushing simulation,” Advances in Materials Science and Engineering, vol. 2018, Article ID 3645720, 12 pages, 2018.
View at: Publisher Site | Google Scholar
M. Wang and W. Wan, “Experimental study on seepage of the maokou limestone with fracture surfaces,” Geotechnical & Geological Engineering, vol. 37, no. 5, pp. 4515–4526, 2019.
View at: Publisher Site | Google Scholar
H. F. Tian, T. Bao, Z. Li, H. Peng, S. You, and S. Xiao, “Determination of constitutive parameters of crystalline limestone based on improved RHT model,” Advances in Materials Science and Engineering, vol. 2022, Article ID 3794898, 11 pages, 2022.
View at: Publisher Site | Google Scholar
A. Al-Swaidani, A. Soud, and A. Hammami, “Improvement of the early-age compressive strength, water permeability, and sulfuric acid resistance of scoria-based mortars/concrete using limestone filler,” Advances in Materials Science and Engineering, vol. 2017, Article ID 8373518, 17 pages, 2017.
View at: Publisher Site | Google Scholar
Z. Wang, L. Zhang, H. Sun, Y. Zhang, and S. Kuang, “Limestone mechanical characteristics under the conditions of different unloading speed of experimental study,” Rock and Soil Mechanics, vol. 32, no. 4, pp. 1045–1050, 2011.
View at: Google Scholar
M. He, W. Cao, and R. Shan, “New technique of bidirectional shaped charge tensile blasting,” Chinese Journal of Rock Mechanics and Engineering, vol. 12, pp. 2047–2051, 2003.
View at: Google Scholar
L. Li, M. Wang, P. Fan, H. Jiang, Y. Cheng, and D. Wang, “Strain rockbursts simulated by low-strength brittle equivalent materials,” Advances in Materials Science and Engineering, vol. 2016, Article ID 5341904, 11 pages, 2016.
View at: Publisher Site | Google Scholar
F. Berto, L. Marsavina, M. R. Ayatollahi, S. V. Panin, and K. I. Tserpes, “Brittle or quasi-brittle fracture of engineering materials 2016,” Advances in Materials Science and Engineering, vol. 2016, Article ID 7094298, 2 pages, 2016.
View at: Publisher Site | Google Scholar
X. Gao, G. Koval, and C. Chazallon, “A discrete element model for damage and fatigue crack growth of quasi-brittle materials,” Advances in Materials Science and Engineering, vol. 2019, Article ID 6962394, 15 pages, 2019.
View at: Publisher Site | Google Scholar
K. Gao, Z. Liu, J. Liu, and F. Zhu, “Study on application of directional shaped charge blasting to weaken reverse fault of comprehensive excavation face,” Chinese Journal of Rock Mechanics and Engineering, vol. 38, no. 7, pp. 1408–1419, 2019.
View at: Google Scholar
X. Yang, D. Yuan, H. Xue et al., “Research on roof cutting and pressure releasing technology of cumulative blasting in deep and high stress roadway,” Geotechnical & Geological Engineering, vol. 39, no. 3, pp. 2653–2667, 2021.
View at: Publisher Site | Google Scholar
Y. Luo, Research on Application of Shaped Charge Effect in Blasting in Geotechnical Engineering, University of Science and Technology of China, Hefei, China, 2006.
H. S. Yadav, “Determination of delayin detonation of a sandwiched explosive impacted by a shaped charge jet,” Defence Science Journal, vol. 70, no. 4, pp. 353–358, 2020.
View at: Publisher Site | Google Scholar
H. Chen, Study on Dynamic Deformation of Shaped Charge Metal Jet Formation and Penetration Process, Nanjing University of Science and Technology, Nanjing, China, 2012.
B. Li and G. Pan, “Influence of Wall thickness of shaped charge Cover on Cutting depth,” Blasting Equipment, vol. 6, pp. 16–19, 1999.
View at: Google Scholar
H.-F. Liu, K. Zheng, and Z. H. U. Chang-qi, “Evaluation of brittleness characteristics of reef limestone based on stress-strain curve,” Rock and Soil Mechanics, vol. 42, no. 3, pp. 673–768, 2021.
View at: Google Scholar
V. Hucka, “Brittleness determination of rocks by different methods,” International Journal of Rock Mechanics and Mining Sciences and Geomechanics Abstracts, vol. 11, no. 10, pp. 389–392, 1974.
View at: Publisher Site | Google Scholar
C. Zhang, Y. Zhu, W. Chu, and N. Liu, “Mechanical characteristics and Hoek-Brown constitutive model of cryptic basalt in Baihetan Hydropower Station,” Chinese Journal of Rock Mechanics and Engineering, vol. 38, no. 10, pp. 1964–1978, 2019.
View at: Google Scholar
G. E. Xiu-run, “Deformation control law of rock fatigue failure, real-time X-ray CT scan of rock and soil mechanics test and a new method for anti-slip stability analysis of slope dam foundation,” Chinese Journal of Geotechnical Engineering, vol. 1, pp. 1–20, 2008.
View at: Google Scholar
R. Yang and Y. Wang, “Understanding and thinking on service safety of underground space engineering,” Journal of Engineering Science, vol. 44, no. 4, pp. 487–495, 2022.
View at: Google Scholar
L. Ji, C. Zhou, S. Lu, and N. Jiang, “Numerical studies on the cumulative damage effects and safety criterion of a large cross-section tunnel induced by single and multiple full-scale blasting,” Rock Mechanics and Rock Engineering, vol. 54, no. 12, pp. 6393–6411, 2021.
View at: Publisher Site | Google Scholar
C. Yang, K. Zhou, Z. Li, X. Xiong, Y. Lin, and Z. Luo, “Numerical modeling on the fracturing and energy evolution of large deep underground openings subjected to dynamic disturbance,” Energies, vol. 13, no. 22, p. 6102, 2020.
View at: Publisher Site | Google Scholar
J. Huang, X. Wei, Y. Luo, H. Gong, T. Liu, and X. Li, “Analysis of the deformation characteristics of the surrounding rock mass of a deep tunnel during excavation through a fracture zone,” Rock Mechanics and Rock Engineering, vol. 55, no. 12, pp. 7817–7835, 2022.
View at: Publisher Site | Google Scholar
W. Wang, B. Xin, H. Wang, and W. Cheng, “Dopa-responsive dystonia: a male patient inherited a novel GCH1 deletion from an asymptomatic mother,” Journal of movement disorders, vol. 13, no. 2, pp. 150–153, 2020.
View at: Publisher Site | Google Scholar
J. Ning, S. Yang, T. Ma, and X. Xu, “Fragment behavior of concrete slab subjected to blast loading,” Engineering Failure Analysis, vol. 138, Article ID 106370, 2022.
View at: Publisher Site | Google Scholar
X. Xu, M. He, C. Zhu, Y. Lin, and C. Cao, “A new calculation model of blasting damage degree—based on fractal and tie rod damage theory,” Engineering Fracture Mechanics, vol. 220, no. C, Article ID 106619, 2019.
View at: Publisher Site | Google Scholar
W. Chen, Numerical Simulation and Application of Annular Shaped Charge, University of Science and Technology of China, Hefei, China, 2015.
Y. Meng, J. Wei, J. Wei, H. Chen, and Y. Cui, “An ANSYS/LS-DYNA simulation and experimental study of circular saw blade cutting system of mulberry cutting machine,” Computers and Electronics in Agriculture, vol. 157, pp. 38–48, 2019.
View at: Publisher Site | Google Scholar

Copyright

Copyright © 2023 Jie Hu et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

PDF Download Citation

Download other formats

Order printed copies