Evolution of the mechanical and strength parameters of hard rocks in the true triaxial cyclic loading and unloading tests

Feng, Xia‐Ting; Gao, Yaohui; Zhang, Xiwei; Wang, Zhaofeng; Zhang, Yan; Han, Qiang

doi:10.1016/j.ijrmms.2020.104349

Cited by 64 publications

(19 citation statements)

References 28 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…That is why the artificial wall technology has been enhanced by a roof cutting to relieve stress at the goaf side [20], [21]. Feng and Wang [22] described an original innovative technology of SR. The entry was planned to be driven under the goaf edge employing split-level longwall panel layout.…”

Section: Chain Pillar Technology and Its Alternativementioning

confidence: 99%

Rock pressure relief is the basic alternative for sustainable underground mining

Nazimko¹,

Zakharova²,

Kusen³

et al. 2021

E3S Web Conf.

View full text Add to dashboard Cite

Retreat longwall mining is the most productive system for underground extraction of tabulated deposits. However, the steady growth of the mining depth dramatically increased the ground pressure in chain pillars protecting the longwall entries. Therefore, several coal industries have tried to shift to pillarless mining and practiced maintenance of the head or tail entry behind the longwall in the stress relief zones using the backfill bodies in the thin coal seams. We modernized the pillarless variant of the retreat longwall system introducing the third roadway, which is driven in the consolidated goaf behind the moving longwall in a stress relief zone. We used a computer code FLAC3D to simulate stress redistribution during pillarless extraction of adjacent panels that assisted to determine optimal parameters of mining layout. This modernized technology provides for sustainable mining due to enhancement of transport, ventilation, safety conditions, and a comfortable environment because of the stability of the underground roadways, which serve the high productive longwalls.

show abstract

Section: Chain Pillar Technology and Its Alternativementioning

confidence: 99%

Rock pressure relief is the basic alternative for sustainable underground mining

Nazimko¹,

Zakharova²,

Kusen³

et al. 2021

E3S Web Conf.

View full text Add to dashboard Cite

show abstract

“…(18) can be used to calculate the relations between ϕ and e p , and the following correlation can be made: Fig. 10 Relations between the octahedral shear stress and effective mean stress represented by the maximum, minimum, and first volumetric strain reversal stresses of hard rocks in true triaxial cyclic loading tests (Feng et al 2020)…”

Section: Cohesion and Internal Friction Angle Characteristicsmentioning

confidence: 99%

“…With crack propagation and coalescence, the degree of rock damage gradually increases, thus Fig. 11 Relations among the cohesion and internal friction angle and the equivalent plastic strains of intact marble in the true triaxial cyclic loading tests (Feng et al 2020) causing a decrease in c o . Once the macroscale failure plane forms in the rock specimen, shearing of the failure plane mainly occurs; thus, c o becomes invariant.…”

Section: Cohesion and Internal Friction Angle Characteristicsmentioning

confidence: 99%

Damage and Failure of Hard Rocks Under True Triaxial Compression

Kong

Gao

Zhang

2020

Handbook of Damage Mechanics

Self Cite

View full text Add to dashboard Cite

To reveal the effect of intermediate principal stress on the damage and failure of hard rocks, the failure evolution of hard rocks under true triaxial compression is reviewed, based on the previous study. From the viewpoint of crack growth under true triaxial compression, different fracture evolution stages of hard rocks, including the elastic stage, stable growth stage, and unstable growth stage, are introduced. Additionally, the effect of the intermediate principal stress on the crack stress thresholds is summarized. It is found that as the intermediate principal stress increases, its effect will first restrict and then promote crack propagation. The energy evolution of the rock cracking process under true triaxial compression is also analyzed. The damage evolution is quantified by damage

show abstract

“…e rock mass in actual excavation projects is mostly anisotropic and presents three-dimensional unequal characteristics [4]. Scientists and engineers assumed that the intermediate principal stress has an important effect on the mechanics and failure characteristics of rock mass under true triaxial loading [5][6][7].…”

Section: Introductionmentioning

confidence: 99%

Unloading Mechanics and Energy Characteristics of Sandstone under Different Intermediate Principal Stress Conditions

Zhang

et al. 2021

Advances in Civil Engineering

View full text Add to dashboard Cite

The TRW-3000 true triaxial rock testing machine was used to conduct loading and unloading tests of sandstone under different σ 2 , and the true triaxial lateral unloading mechanics and energy characteristics of sandstone under different σ 2 were studied. The experimental results show the following: (1) compared with the results of the loading test, the peak strength of the sandstone under the unloading σ 3 path is reduced, the unloading direction has obvious expansion and deformation, and the amount of expansion increases significantly with the increase of σ 2 ; sudden brittle failure occurs at the end of unloading. E gradually decreases with the increase of H, and it performs well to use the cubic polynomial to fit the curve of E-H. (2) The Mogi–Coulomb strength criterion can accurately describe the true triaxial strength characteristics of sandstone under loading and unloading conditions. Compared with the results of the loading test, the values of c and φ obtained based on this criterion under the unloading σ 3 path are reduced. (3) Under the condition of unloading σ 3 , U, U e , and U d , when the specimen is broken, are all linearly positively correlated with σ 2 . U d increases nonlinearly with the increase of H, and as σ 2 increases, the slope of the U d -H curve becomes larger, and the specimen consumes more energy under the same unloading amount. Most of the energy absorbed by the specimen under the unloading σ 3 path is converted into U e , but as σ 2 increases, U d / U increases, and the energy consumed when the specimen is broken is greater.

show abstract

Evolution of the mechanical and strength parameters of hard rocks in the true triaxial cyclic loading and unloading tests

Cited by 64 publications

References 28 publications

Rock pressure relief is the basic alternative for sustainable underground mining

Rock pressure relief is the basic alternative for sustainable underground mining

Damage and Failure of Hard Rocks Under True Triaxial Compression

Unloading Mechanics and Energy Characteristics of Sandstone under Different Intermediate Principal Stress Conditions

Contact Info

Product

Resources

About