Study on the raising technique using one blast based on the combination of long-hole presplitting and vertical crater retreat multiple-deck shots

Liu, Kewei; Li, Xudong; Hao, Hong; Li, Xibing; Sha, Yanyan; Liu, Xiling

doi:10.1016/j.ijrmms.2018.11.012

Cited by 56 publications

(12 citation statements)

References 14 publications

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“…In conjunction with the development of high-speed computer algorithms, numerical simulation, as an effective method in geotechnical engineering [25][26][27][28], has been widely applied to investigate EDZs. Golshani et al [29] simulated the excavation damage of a circular opening in a brittle rock mass in terms of an extended micromechanics-based continuum damage model.…”

Section: Introductionmentioning

confidence: 99%

Evaluation of Excavation-Damaged Zone around Underground Tunnels by Theoretical Calculation and Field Test Methods

et al. 2019

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Excavation-damaged zones (EDZs) induced in underground mining and civil engineering potentially threaten tunnel safety and stability, and increase construction and support costs. In this paper, an investigation of the excavation damaged zone (EDZ) around roadways in Fankou lead-zinc mine in Guangzhou, China is performed by applying a seismic velocity method accompanied by SET-PLT-01 nonmetallic ultrasonic detector. Meanwhile, the in situ stress in the mining area was measured based on the stress relief method with the Swedish high-precision LUT system. The results indicate that the stress field is dominated by the maximum horizontal tectonic stress, and the extents of the EDZ on the roof-floor region are greater than that on the sidewall. In addition, both of the in situ stresses and EDZs show an increasing trend with an increase of depth. Analytical solutions of EDZ around circular openings in the brittle rock mass subjected to non-hydrostatic stress fields are presented in terms of the Mohr–Coulomb and generalized Hoek–Brown criteria, and validated by several cases mentioned above. The extents of EDZ solved by closed-form solutions were found to be in a great agreement with those obtained in the field. Finally, a series of parametric studies are conducted to investigate the effects of cohesion (c), friction angle (φ), geological strength index (GSI), mi, uniaxial compressive strength (σc), and disturbance factor (D) on EDZ. It is shown that the effects of c, φ, GSI, and σc are significant; however, more attention should be paid to consider the dynamic disturbances induced by mechanical drilling, blasting, and seismic waves in tunnel excavations or operations.

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Section: Introductionmentioning

confidence: 99%

Evaluation of Excavation-Damaged Zone around Underground Tunnels by Theoretical Calculation and Field Test Methods

et al. 2019

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“…e Material Type 8 of * MAT_HIGH_EXPLOSIVE_BURN in LS-DYNA library combined with the Jones-Wilkens-Lee (JWL) equation-ofstate (EOS) [63] is chosen to describe the pressure generated by the expansion of the detonation product. It has been widely applied in the calculations of rock blasting [64][65][66].…”

Section: Materials Model For Explosivementioning

confidence: 99%

Study of the Rock Crack Propagation Induced by Blasting with a Decoupled Charge under High In Situ Stress

Liu

Yang

2020

Advances in Civil Engineering

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The high in situ stress can significantly affect the blast-induced rock fragmentation and cause difficulties in deep mining and civil engineering where the drilling and blasting technique is applied. In this study, the rock crack propagation induced by blasting under in situ stress is first analyzed theoretically, and then a numerical model with a decoupled charge in LS-DYNA is developed to reveal how the initiation and propagation of rock cracks are under high in situ stress. Through simulation, the mechanisms of blast-induced crack evolution under various hydrostatic pressures and nonhydrostatic pressures are investigated, and the differences in crack evolution with specific decoupling coefficients are compared. According to the simulation, three damage zones, i.e., the crushed zone, the nonlinear fracture zone, and the radial crack propagation zone, are formed, and the radial crack evolution is greatly suppressed by the high in situ stress which has no much influence on the crack propagation in the crushed and the nonlinear fracture zones. The velocity of crack propagation is slightly reduced, and the process of crack propagation is stopped early when the rock is subjected to high in situ stress. Furthermore, the numerical analysis indicates that the crack grows preferentially in the direction of maximum principal stress, and the radial crack propagation is predominantly controlled by the preloaded pressure, which is vertical to the crack propagation direction. Based on the numerical results, it is suggested that the optimal decoupling coefficients for rock cracking are 2.65, 1.87, 1.37, and 1.22 for 0, 10, 20, and 30 MPa, respectively. This study provides not only an analysis of the rock crack evolution under high in situ stress but also a reference for resolving excavation difficulties in deep mining.

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“…Adopting bidirectional energy blasting technology, to pack the explosives in the tube, symmetrical openings on both sides of the energy collecting tube form a weak blasting surface [31][32][33]. As shown in Figure 4(a), after the explosive is detonated, the detonation wave will form a directional concentrated energy flow in the direction of the weak surface on both sides of the energy collecting tube, forming a cutting effect on the roof strata.…”

Section: Scheme Designmentioning

confidence: 99%

Presplitting Blasting the Roof Strata to Control Large Deformation in the Deep Mine Roadway

Yang

Huang

et al. 2020

Advances in Civil Engineering

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As the mining depth increases, under the influence of high ground stress, the surrounding rock of deep mine roadways shows soft rock characteristics. Under the influence of mining disturbance at the working face, large deformation of the roadway has occurred. To control the large deformation of the roadway, many mines have adopted the form of combined support, which has continuously increased the support strength and achieved a certain effect. However, since the stress environment of the surrounding rock of the roadway has not been changed, large deformation of the roadway still occurs in many cases. Based on the theoretical basis of academician Manchao He’s “short cantilever beam by roof cutting,” this paper puts forward the plan of “presplitting blasting + combined support” to control the large deformation of the deep mine roadways. Without changing the original support conditions of the roadway, presplitting blasting the roof strata of the roadway, by cutting off the mechanical connection of the roof strata between the roadway and gob, improves the stress distribution of the roadway to control the large deformation. Through field tests, the results show that after presplitting blasting the roadway roof, the roadway roof subsidence is reduced by 47.9%, the ribs displacement is reduced by 45.7%, and the floor heave volume is reduced by 50.8%. The effect is significant.

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Study on the raising technique using one blast based on the combination of long-hole presplitting and vertical crater retreat multiple-deck shots

Cited by 56 publications

References 14 publications

Evaluation of Excavation-Damaged Zone around Underground Tunnels by Theoretical Calculation and Field Test Methods

Evaluation of Excavation-Damaged Zone around Underground Tunnels by Theoretical Calculation and Field Test Methods

Study of the Rock Crack Propagation Induced by Blasting with a Decoupled Charge under High In Situ Stress

Presplitting Blasting the Roof Strata to Control Large Deformation in the Deep Mine Roadway

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