Burden Effects on Rock Fragmentation and Damage, and Stress Wave Attenuation in Cut Blasting of Large-Diameter Long-Hole Stopes

Zhang, Zongguo; Qiu, Xianyang; Shi, Xiuzhi; Luo, Zhihua; Chen, Hui; Zong, Chengxing

doi:10.1007/s00603-023-03512-y

Cited by 8 publications

(4 citation statements)

References 51 publications

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“…In contrast, the peak strain of 2# is positive (tensile strain, and the larger the positive value, the higher the peak). This phenomenon is consistent with the trends obtained in previous research [48], and it is observed that the peak strain of 2# is much larger than that of 1#, indicating that the reflected tensile wave plays a significant role in the formation of the blasting crater on the bottom surface of the test block. On the other hand, the strain variations of 3# and 4# are similar, showing an initial compressive strain followed immediately by tensile strain.…”

Section: Dynamic Strainsupporting

confidence: 92%

“…The densities of DDNP and RDX are 0.7 g/cm 3 and 1.68 g/cm 3 , respectively. The explosive heat for DDNP and RDX is 1400 KJ/kg and 5600 KJ/kg, respectively, while the detonator velocity for DDNP and RDX is 3800 m/s and 8400 m/s, respectively [45][46][47][48]. Based on the mass ratio of the two explosives, the detonator explosive charge's calculated density and detonation velocity are 1.13 g/cm 3 and 6800 m/s, respectively [46,48].…”

Section: Mortar Test Block and Explosive Propertiesmentioning

confidence: 99%

“…In addition, to some extent, this is also beneficial for reducing secondary disasters caused by blasting. Generally, the ratio of the energy used for rock fracturing and fragmentation (fragmentation energy, E p ) to the total chemical energy of the explosives (E s ) is defined as the fragmentation energy consumption utilization rate (η) [48,52], as shown in Equation (2). A higher energy utilization rate indicates less waste of explosive energy and is more favorable for rock fragmentation.…”

Section: Fragmentation Energy Consumption Utilization Ratementioning

confidence: 99%

“…where H is explosive heat, KJ/kg, Q is the quantity of the explosive charge. Numerous research findings indicate that the energy used for rock fracturing and fragmentation is related to the newly increased surface area (A x ) during the rock fracture process [2,47,48,53,54]. A x can be calculated by subtracting the original surface area of the rock block (A y ) from the total surface area of all fragmented rock blocks (A s ).…”

Section: Fragmentation Energy Consumption Utilization Ratementioning

confidence: 99%

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Experiment Study of Stemming Length and Stemming Material Impact on Rock Fragmentation and Dynamic Strain

Shi,

Zhang,

Qiu

et al. 2023

Sustainability

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Stemming length and stemming materials are crucial factors in blasting design, which affect the sustainability of mining. This study investigates the influence of stemming length and stemming material on rock fragmentation, stemming recoil, and surface strain response through 15 small-scale model blasting tests. The results indicate that when using clay as a stemming material, increasing the stemming length facilitates rock fragmentation and reduces the stemming recoil area. The strain measurements show that both tensile and compressive strain peaks on the blasting crater surface increase with the growth of stemming length, while the strain peaks on the upper surface decrease. A comparative analysis of different stemming materials reveals that clay performs the best, exhibiting the highest total weight of fragments, blasting crater size, and fragmentation energy utilization. Strain results indicate that clay stemming generates more significant strain peaks and higher strain loading rates on the blasting crater surface, favoring a more concentrated application of explosive energy on the crater surface and improving rock fragmentation. Sand + clay stemming yields fragments more concentrated in medium-sized particles than clay stemming. If the blasting goal is to increase the utilization efficiency of explosive energy and reduce the hazards of stemming recoil, it is recommended to use clay stemming. In addition, if uniform fragmentation is desired (reducing large and fine particles), a combination of sand + clay stemming can be used. These findings have practical implications for optimizing blasting design and engineering applications.

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Section: Dynamic Strainsupporting

confidence: 92%

Section: Mortar Test Block and Explosive Propertiesmentioning

confidence: 99%

Section: Fragmentation Energy Consumption Utilization Ratementioning

confidence: 99%

Section: Fragmentation Energy Consumption Utilization Ratementioning

confidence: 99%

See 2 more Smart Citations

Experiment Study of Stemming Length and Stemming Material Impact on Rock Fragmentation and Dynamic Strain

Shi,

Zhang,

Qiu

et al. 2023

Sustainability

Self Cite

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In Situ Tests Comparing the Support Effects of Thin Spray-on Liner and Shotcrete on a Roadway Subjected to Blasting

Zhang,

Shi,

Qiu

et al. 2023

Rock Mech Rock Eng

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Damage and Fragmentation of Rock Under Multi-Long-Hole Blasting with Large Empty Holes

Lan,

Cheng,

Zhou

et al. 2024

Rock Mech Rock Eng

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The technique of multi-long-hole blasting with large empty holes has been used in practice to break rock mass. However, the damage mechanism of rock mass surrounded by empty holes and boreholes under this type of blasting has not yet been well-understood and identified, which may lead to inappropriate design of the configurations of empty holes for multi-long-hole blasting. The present study investigates the damage modes and mechanism of rock mass under multi-long-hole blasting with large empty holes by conducting a field test and numerical simulations. The results show that multi-long-hole blasting with empty holes mainly causes compressive damage of rock mass around boreholes, reflected tensile damage near empty holes and ground surface, bending-induced tensile damage between empty holes and boreholes, shear damage along the side tangents and bottom of empty holes and boreholes, and tensile damage along the connection of boreholes caused by the superposition of stress waves. In addition, parametric studies are conducted to examine the effects of depths and diameters of empty holes and the spacing between boreholes and empty holes on the damage and fragmentation of rock mass under blast loads. It is found that the flexural stiffness and confined levels of rock mass can be greatly influenced by the variation of configurations of empty holes, which thus induces different damage and fragmentation under multi-long-hole blasting. Analytical formulas for the evaluation of shear and bending-induced damage of rock mass under multi-long-hole blasting are finally proposed to provide references for the design of empty holes in multi-long-hole blasting.

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Burden Effects on Rock Fragmentation and Damage, and Stress Wave Attenuation in Cut Blasting of Large-Diameter Long-Hole Stopes

Cited by 8 publications

References 51 publications

Experiment Study of Stemming Length and Stemming Material Impact on Rock Fragmentation and Dynamic Strain

Experiment Study of Stemming Length and Stemming Material Impact on Rock Fragmentation and Dynamic Strain

In Situ Tests Comparing the Support Effects of Thin Spray-on Liner and Shotcrete on a Roadway Subjected to Blasting

Damage and Fragmentation of Rock Under Multi-Long-Hole Blasting with Large Empty Holes

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