Dynamic Behavior of Fault Slip Induced by Stress Waves

In order to increase the mining rate of underground coal resources, an innovative nonpillar underground coal mining approach (fracturing roofs to maintain entry (FRME)) has been widely applied in China. The effect of roof fracturing determines whether the entry can be retained successfully or not. In this work, the tail entry of 21304 panel in Chengjiao Coal Mine (China) has been considered as the test site. The coal mine is located approximately 900 m underground. A numerical investigation on the relationship between the entry stability and roof fracturing angle was conducted. In order to investigate the reasonable scope of roof fracturing angle under static and dynamic loadings, the double-yield model was employed to simulate the gob materials, and the input parameters of the model were calibrated meticulously using the method of inversion analysis. Furthermore, dynamic loading was applied to research the influence of fracture of hard rock strata on the entry stability. The global model was validated with the field data. The simulation results demonstrate that the reasonable scope of the roof fracturing angle is 10–20°, in which case the distributions of vertical stress are favorable to the stability of gob-side entry. Additionally, the dynamic responses were found to be relatively moderate. The numerical method could provide a significant reference for the design of FRME approach.

Section: Dynamic Modelingmentioning

confidence: 99%

Numerical Investigation of the Influence of Roof Fracturing Angle on the Stability of Gob‐Side Entry Subjected to Dynamic Loading

Guo

Zhang

et al. 2019

“…timing for reactivation of the faults [28][29][30][31]. During the propagation of a dynamic/blast wave, part of the stress wave energy will be absorbed by the preexisting faults, resulting in an increase of energy before it arrives at the faults and the attenuation of energy after crossing the faults [32][33][34]. e stress wave probably originates from ruptures of rock and coal masses, breakage, and/or collapse of the roof or blast loading in the stope.…”

Section: Shock and Vibrationmentioning

confidence: 99%

“…e stress wave probably originates from ruptures of rock and coal masses, breakage, and/or collapse of the roof or blast loading in the stope. e energy disturbance along and through the preexisting faults has a large influence on the evolution and distribution of dynamic disasters such as rockbursts and the sudden reactivation of faults in coal mining [33].…”

Section: Shock and Vibrationmentioning

confidence: 99%

See 1 more Smart Citation

Explosion‐Induced Stress Wave Propagation in Interacting Fault System: Numerical Modeling and Implications for Chaoyang Coal Mine

Feng

Zhang

Ali

2019

Exploring the propagation of stress waves in rocks with preexisting discontinuities is of great importance to reveal rock and geological engineering problems, particularly dynamic disasters like earthquakes and rockbursts in underground coal mining. In this paper, six 3D models established with COMSOL Multiphysics are employed to explore the influence of two preexisting faults with different orientations on the propagation process of explosion-induced stress waves and the reflection effect. Considering the propagation process of stress waves, the interactive effect between two different size faults is discussed. The results show that the dip angles of the preexisting fault and the differences of the elastic modulus, density, and Poisson’s ratio between faults and rocks have great influence on the distribution of stresses and strain-energy density. Immediately after the stress wave induced by blasting arrived at preexisting fault A, a relatively high concentration of the strain-energy density was observed at the last wave before passing through fault A. The presence of faults leads to the reflection of most of the blast energy. When the stress wave propagates across fault A, the strain energy stored in the stress wave becomes attenuated; thus, most strain energy was absorbed by the fault’s domain. Finally, the modeling results were implicated in Chaoyang Coal Mine to account for the distribution of the observed seismic events. This study has guiding significance for the attenuation law of stress waves passing through joint/fissure zones in geological engineering, earthquake engineering, and underground mining engineering.

“…Unfortunately, dynamic rupture events in recent past had posed severe threats to mine workers thus adversely affecting continuous production in coal mines [1]. In recent years, many scholars have studied dynamic rupture induced by hard rock [14], coal pillar [15,16], fault [17,18] and tectonic stress [19,20], employing stress, strain and energy, and so forth as frequently used parameters but very few literatures had focused on floor dynamic rupture. This paper investigates mechanical mechanism of floor dynamic rupture by adopting an elastic thin plate theory.…”

Section: Introductionmentioning

confidence: 99%

Investigation into Mechanism of Floor Dynamic Rupture by Evolution Characteristics of Stress and Mine Tremors: A Case Study in Guojiahe Coal Mine, China

Liu

Javed

Gong

et al. 2018

In order to explore the mechanism of floor dynamic rupture, the current study adopts a thin plate model to further investigate the condition of floor failure. One of the possible explanations could be floor buckling due to high horizontal stress and dynamic disturbance ultimately leading to rapid and massive release of elastic energy thus inducing dynamic rupture. Seismic computed tomography and 3D location were employed to explore the evolution characteristics of floor stress distribution and positions of mine tremors. In the regions of floor dynamic rupture, higher P-wave velocity was recorded prior to the dynamic rupture. On the contrary, relatively lower reading was observed after the dynamic rupture thus depicting a high stress concentration condition. Meanwhile, evolution of mine tremors revealed the accumulation and subsequent release of energy during the dynamic rupture process. It was further revealed that dynamic rupture was induced due to the superposition of static and dynamic stresses: (i) the high static stress concentration due to frontal and lateral abutment stress from coal pillar and (ii) dynamic stress from the fracture and caving of coal pillar, hard roof, and key stratum. In the later part of this study, the floor dynamic rupture occurrence process would be reproduced through numerical simulations within a 0.6 sec time frame. The above-mentioned findings would be used to propose a feasible mechanism for prewarning and prevention of floor dynamic rupture using seismic computed tomography and mine tremors 3D location.