A new rockburst criterion of stress–strength ratio considering stress distribution of surrounding rock

Num Anal Meth Geomechanics

Luo

Gong

et al. 2023

Self Cite

To explore the mechanical characteristics and failure mechanisms of rock shear fracture under dynamic disturbance, the laboratory shear test and numerical simulation based on particle flow code (PFC) were carried out, and the mesoscopic degradation characteristics and energy dissipation mechanisms of rock shear fracture were analyzed. The results show that: (1) The crack initiation stress of rock under the disturbance condition is relatively reduced by 20%–29%, and there is a “shear fracture weakening effect.” The frequent alternating effect of stress concentration and release at the post‐peak failure stage is more obvious. (2) The number of cracks in rock under shear action shows the evolution of “calm → low speed growth → rapid increase → decrease of amplification → stabilization” with the increase of shear displacement. Compared with the conventional shear test, more cracks, and wider debris zones are formed. The number of cracks increases by 53%–106%, and the number of debris increases by 31%–138%. (3) The energy change trend of disturbance shear fracture test is basically consistent with that of conventional shear test. With the increase of normal stress, the input energy, elastic strain energy and dissipation energy of rock failure point show a certain linear growth feature. Compared with the conventional shear test, the input energy and stored strain energy of the failure point in the disturbance shear test are smaller, with relative reduction of 16.5% and 22.1%. Namely, the normal frequent disturbance reduces the energy storage capacity and failure resistance of rock.

Section: Introductionmentioning

confidence: 99%

Investigations on the macro‐meso mechanical properties and energy dissipation mechanism of granite shear fracture under dynamic disturbance

Num Anal Meth Geomechanics

Luo

Gong

et al. 2023

Self Cite

“…As ground stress increases and environmental complexity intensifies, the likelihood and impact of rock bursts also rise (Li et al, 2012;Gale, 2018). To ensure mining efficiency and safety, it is necessary to study the prediction of rock burst (Singh, 1989;Cai et al, 2022;Liu et al, 2023). Typically, rock burst proneness is regarded as a prerequisite for determining the likelihood of rock burst (Feng et al, 2015;Liu S M et al, 2020).…”

Section: Introductionmentioning

confidence: 99%

“…Furthermore, the combined effect of high ground stress and external force disturbance is closely related to rock burst occurrence (Du et al, 2016). By enhancing the strain hardening effect, increasing the strain rate leads to a strong brittleness deformation of rock, making it an essential factor in energy release-induced rock burst (Liu et al, 2023).…”

Section: Introductionmentioning

confidence: 99%

Experimental investigation into rock burst proneness of rock materials considering strain rate and size effect

Zhao

et al. 2023

Front. Earth Sci.

In deep rock engineering, evaluating the likelihood of rock burst is imperative to ensure safety. This study proposes a new metric, the post-peak dissipated energy index, which accounts for strain rate and size effects in assessment of the rock burst proneness of a rock mass. To investigate rock burst proneness, conventional compression tests were conducted on limestone and slate samples with different length to diameter (L/D) ratios (ranging from 0.3 to 1.5) at four different strain rates (0.005, 0.01, 0.5, and 1.0 s−1). Based on the testing observations, the actual rock burst proneness was classified into three categories (no risk, low risk, and high risk). A new criterion was also established using the post-peak dissipated energy index, which is the ratio of elastic energy to total dissipated energy. The impact of the strain rate and L/D ratio on rock burst proneness was analyzed. The results indicated that increased strain rates cause a strong hardening effect, leading to staged growth of rock burst proneness. However, the rock burst proneness decreases non-linearly with the increasing L/D ratio. The accuracy of the proposed criterion was validated by comparison with existing criteria, demonstrating that the energy-based index ensures a reliable evaluation of the rock burst proneness of a rock mass. The proposed method has excellent potential for practical application in deep rock engineering.

“…The thermal fatigue effects of rock have been considered as an important factor that can evidently affect the physical–mechanical behaviors of rocks like its microstructure, strength, and deformation instability process 1–5 . The thermal fatigue damage induced by high temperature will induce the change of internal structure of rocks, 6,7 resulting in the destructive instability of rock mass in some geotechnical engineering applications such as enhanced geothermal system, nuclear waste storge, deep mining, rock drilling, and rock engineering exposed to fire or explosion 8–12 . Currently, the thermal fatigue damage of rock has become a design factor that cannot be ignored in rock engineering under high‐temperature environment 13,14 .…”

Section: Introductionmentioning

confidence: 99%

“…[1][2][3][4][5] The thermal fatigue damage induced by high temperature will induce the change of internal structure of rocks, 6,7 resulting in the destructive instability of rock mass in some geotechnical engineering applications such as enhanced geothermal system, nuclear waste storge, deep mining, rock drilling, and rock engineering exposed to fire or explosion. [8][9][10][11][12] Currently, the thermal fatigue damage of rock has become a design factor that cannot be ignored in rock engineering under high-temperature environment. 13,14 Consequently, it is essential to investigate the effects of high temperature on the failure mechanism of rocks.…”

Section: Introductionmentioning

confidence: 99%

Experimental study on thermal fatigue damage and failure mechanisms of basalt exposed to high‐temperature treatments

Niu

Fatigue Fract Eng Mat Struct

et al. 2023

Self Cite

Understanding the effects of thermal fatigue damage on the failure mechanisms of rocks is a key concern in underground engineering. The effects of high temperature on the physical-mechanical behaviors and the failure mechanism of basalt under uniaxial compression are investigated with a combination of acoustic emission (AE), computed tomography (CT), and scanning electron microscope (SEM). The high temperature heavily affects the physicalmechanical properties of basalt but has no effect on the mineral compositions. The evolution characteristics of inter-event time function F(τ) and cumulative AE energy can be employed to characterize the fracture process of thermally damaged basalt. The damage mechanisms of thermal fatigue are attributed to the occurrence of intergranular cracks, intragranular cracks, and transgranular cracks and irregular holes within basalt. The failure mechanisms of basalt change from shear fracture to mixed tensile-shear fracture and finally to tensile fracture based on the statistical characteristics of low and high dominant frequencies. K E Y W O R D S acoustic emission, dominant frequency, failure mechanism, high-temperature treatment, thermal fatigue damage, uniaxial compression Highlights • The thermal fatigue effects on the physical-mechanical behaviors of basalt are studied. • The relationship between failure process and AE characteristics is constructed. • The damage mechanisms of thermal fatigue for basalt are revealed. • The failure mechanisms of basalt under uniaxial compression are revealed.