The shape effect and rock mass structural control for mine pillar design

Silva, L. A. Ayres da; Sansone, Eduardo César

doi:10.1201/b15683-94

Cited by 3 publications

References 0 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Hence, the values of Cpav in Eq. (6) and κ in Eq. 7can be deduced, respectively, which are 0.25 and 2.67.…”

Section: Discussionmentioning

confidence: 99%

“…Hence, it is necessary to study the pillar stability for better engineering applications. Comprehensive understanding of the failure mechanism and micro-fracture behavior of pillar at varying conditions is necessary to develop the optimal pillar strength design [2][3][4][5][6] . Past literature focused on optimizing the experimental conditions as these significantly affected the rock material or rock-like material fracture behavior [7][8][9][10][11][12][13] .…”

Section: Experimental Study On Granite Acoustic Emission and Micro-frmentioning

confidence: 99%

See 1 more Smart Citation

Experimental study on granite acoustic emission and micro-fracture behavior with combined compression and shear loading: phenomenon and mechanism

Cao

Chen

et al. 2020

Sci Rep

View full text Add to dashboard Buy / Rent full text

One element that is essential to consider in underground mining engineering applications is the possibility of pillar failure, which can result in deadly geological disasters, including earthquakes and surface subsidence. Pillars are commonly present under an inclined state and are significantly dependent upon combined compression and shear loading. However, many scholars regard the pure uniaxial compression strength (UCS) of rock as the main evaluation index of pillar strength, which is inconsistent with the field practice. Hence, the present study developed a novel combined compression and shear test (C-CAST) system, which was applied in the investigative acoustic emission (AE) experiments to characterize the failure mechanism and micro-fracture behavior of granite specimens at different inclination angles. The experimental results presented the exponential decrease of UCS of inclined specimens with increase in the shear stress component. Changes in the inclination angle with a range of 0°–10° produced a splitting-shear failure fracture mode from the initial splitting failure. In comparison, an increase in the inclination angle from 10° to 20° produced a single shear failure fracture mode from the initial combined splitting-shear failure. The specimens exhibited nonlinearly reduced microcrack initiation (CI) and damage (CD) thresholds following an increase in the inclination angle, suggesting the dependence of the microcrack initiation and propagation on the shear stress component. The ratio of CI and CD thresholds to inclined UCS varies within a certain range, indicating that the ratio may be an inherent property of granite specimens and is not affected by external load conditions. Additionally, the rock fracture behavior was largely dependent upon the mechanism of shear stress component, as validated by the microcrack initiation and growth. Finally, a modified empirical formula for pillar strength is proposed to investigate the actual strength of inclined pillar. Results of a case study show that the modified formula can be better used to evaluate the stability of inclined pillars.

show abstract

“…Hence, the values of Cpav in Eq. (6) and κ in Eq. 7can be deduced, respectively, which are 0.25 and 2.67.…”

Section: Discussionmentioning

confidence: 99%

Section: Experimental Study On Granite Acoustic Emission and Micro-frmentioning

confidence: 99%

Experimental study on granite acoustic emission and micro-fracture behavior with combined compression and shear loading: phenomenon and mechanism

Cao

Chen

et al. 2020

Sci Rep

View full text Add to dashboard Buy / Rent full text

show abstract

“…The laboratory results showed that the strength reduction factors can be used to predict the strength of the inclined specimens at any width-to-height ratios. The laboratory test results are the basis for understanding the strength of the large-scale pillars [27,28]. Therefore, as the strength reduction factors are consistent throughout all the W/H ratios for a specific inclination in the laboratory specimens, the strength reduction factors should be consistent throughout all the W/H ratios in largescale pillars.…”

Section: Strength Reduction Factors For Numerically Simulated Pillarsmentioning

confidence: 99%

Laboratory and Numerical Investigation on Strength Performance of Inclined Pillars

Jessu¹,

Spearing²,

Sharifzadeh³

2018

Energies

View full text Add to dashboard Buy / Rent full text

Pillars play a critical role in an underground mine, as an inadequate pillar design could lead to pillar failure, which may result in catastrophic damage, while an over-designed pillar would lead to ore loss, causing economic loss. Pillar design is dictated by the inclination of the ore body. Depending on the orientation of the pillars, loading can be axial (compression) in horizontal pillars and oblique (compression as well as shear loading) in inclined pillars. Empirical and numerical approaches are the two most commonly used methods for pillar design. Current empirical approaches are mostly based on horizontal pillars, and the inclination of the pillars in the dataset is not taken into consideration. Laboratory and numerical studies were conducted with different width-to-height ratios and at different inclinations to understand the reduction in strength due to inclined loading and to observe the failure mechanisms. The specimens’ strength reduced consistently over all the width-to-height ratios at a given inclination. The strength reduction factors for gypsum were found to be 0.78 and 0.56, and for sandstone were 0.71 and 0.43 at 10° and 20° inclinations, respectively. The strength reduction factors from numerical models were found to be 0.94 for 10° inclination, 0.87 for 20° inclination, 0.78 for 30° inclination, and 0.67 for 40° inclination, and a fitting equation was proposed for the strength reduction factor with respect to inclination. The achieved results could be used at preliminary design stages and can be verified during real mining practice.

show abstract

“…The strength of the pillar decreases with the increase in pillar height at a constant pillar width-to-height (W/H) ratio [24]. Many studies have been conducted to understand the effect of size, which shows that at a constant W/H ratio, as the sample size increases, the strength of the sample decreases [25]. Alternatively, at a constant blast thickness, the blast would encompass a larger amount of a smaller pillar and, conversely, a smaller amount of a larger pillar.…”

Section: Effect Of Pillar Heightmentioning

confidence: 99%

A Parametric Study of Blast Damage on Hard Rock Pillar Strength

Jessu¹,

Spearing²,

Sharifzadeh³

2018

Energies

View full text Add to dashboard Buy / Rent full text

Pillar stability is an important factor for safe working and from an economic standpoint in underground mines. This paper discusses the effect of blast damage on the strength of hard rock pillars using numerical models through a parametric study. The results indicate that blast damage has a significant impact on the strength of pillars with larger width-to-height (W/H) ratios. The blast damage causes softening of the rock at the pillar boundaries leading to the yielding of the pillars in brittle fashion beyond the blast damage zones. The models show that the decrease in pillar strength as a consequence of blasting is inversely correlated with increasing pillar height at a constant W/H ratio. Inclined pillars are less susceptible to blast damage, and the damage on the inclined sides has a greater impact on pillar strength than on the normal sides. A methodology to analyze the blast damage on hard rock pillars using FLAC 3D is presented herein.

show abstract

The shape effect and rock mass structural control for mine pillar design

Cited by 3 publications

References 0 publications

Experimental study on granite acoustic emission and micro-fracture behavior with combined compression and shear loading: phenomenon and mechanism

Experimental study on granite acoustic emission and micro-fracture behavior with combined compression and shear loading: phenomenon and mechanism

Laboratory and Numerical Investigation on Strength Performance of Inclined Pillars

A Parametric Study of Blast Damage on Hard Rock Pillar Strength

Contact Info

Product

Resources

About