Electromagnetic precursor of rock collapse

1993 ◽  
Vol 29 (2) ◽  
pp. 106-110 ◽  
Author(s):  
V. V. Lasukov ◽  
Sh. R. Mastov
Keyword(s):  
Rock Collapse ◽  
Electromagnetic Precursor

scholarly journals Rockslides on limestone cliffs with subhorizontal bedding in the southwestern calcareous area of China

2014 ◽  
Vol 14 (9) ◽  
pp. 2627-2635 ◽  
Author(s):  
Z. Feng ◽  
B. Li ◽  
Y. P. Yin ◽  
K. He
Keyword(s):  
Numerical Modeling ◽  
Rock Mass ◽  
Hard Rock ◽  
Compression Fracture ◽  
Field Observations ◽  
Mountainous Areas ◽  
Hard Rocks ◽  
Rupture Plane ◽  
Rock Collapse ◽  
Cliff Retreat

Abstract. Calcareous mountainous areas are highly prone to geohazards, and rockslides play an important role in cliff retreat. This study presents three examples of failures of limestone cliffs with subhorizontal bedding in the southwestern calcareous area of China. Field observations and numerical modeling of Yudong Escarpment, Zengzi Cliff, and Wangxia Cliff showed that pre-existing vertical joints passing through thick limestone and the alternation of competent and incompetent layers are the most significant features for rockslides. A "hard-on-soft" cliff made of hard rocks superimposed on soft rocks is prone to rock slump, characterized by shearing through the underlying weak strata along a curved surface and backward tilting. When a slope contains weak interlayers rather than a soft basal, a rock collapse could occur from the compression fracture and tensile split of the rock mass near the interfaces. A rockslide might shear through a hard rock mass if no discontinuities are exposed in the cliff slope, and sliding may occur along a moderately inclined rupture plane. The "toe breakout" mechanism mainly depends on the strength characteristics of the rock mass.

ANALYSIS OF PRODUCTION RISK FROM CRUSHES OF ROCKS AT EXCAVATION SITES, TAKING INTO ACCOUNT WAYS OF PROTECTION

2021 ◽  
pp. 124-134
Author(s):  
Iaroslav Liashok ◽  
◽  
Serhii Podkopaiev ◽  
Yuliia Simonova ◽  
Hennadii Boichenko ◽  
...  
Keyword(s):  
Practical Significance ◽  
Production Risk ◽  
Venn Diagrams ◽  
Deep Coal Mine ◽  
Geological Conditions ◽  
Rock Collapse ◽  
Available Information ◽  
Decision Making Model ◽  
Excavation Site ◽  
Industrial Risk

Purpose. To assess the production risk of rock collapse in a deep coal mine to identify hazards in the workplaces of the excavation site, taking into account different methods of protection of workings. Methods. A comprehensive approach was used, which included: analysis and generalization of known research; expert evaluation; use of the basic provisions of probability theory and set algebra (Venn diagrams), the method of estimating the production risk of Fine-Kinney; processing, analysis and interpretation of the obtained results. Results. Problems and sources of industrial risk from rock collapses during maintenance of workings, risk-forming factors that contribute to the threat of dangerous events at the excavation site are analyzed. The decision-making model is considered, which is based on the description of situations when the production risk of the dangerous factor “landslides and collapses” in the maintenance of preparatory workings depends on the result of choosing an alternative method of protection of the retractable lane. For excavation sites under the same mining and geological conditions for all workplaces, the probability of receiving consequences from dangerous events due to uncertain conditions of their implementation has been established. It is fixed that the realization of this production risk is influenced by low reliability and inefficiency of the practiced methods of protection of excavations. Risk analysis is defined as the systematic use of available information to identify hazards in the maintenance of long workings. Novelty. A model for monitoring the production risk of rock collapses in excavations of deep coal mines is proposed, which allows assessing the dynamics of the threat at the stage of technical decisions related to the choice and justification of the method of protection of workings taking into account the interaction of risk factors. Practical significance. When formulating measures to reduce the risk of dangerous events at the excavation site, it is necessary to take into account that the production risk of rock collapse while maintaining the workings depends largely on the method of protection and effectiveness of technological measures.

scholarly journals Rockslides on limestone cliffs with sub-horizontal bedding in the southwestern calcareous area, China

2014 ◽  
Vol 2 (6) ◽  
pp. 4299-4330
Author(s):  
Z. Feng ◽  
B. Li ◽  
Y. P. Yin ◽  
K. He
Keyword(s):  
Rock Mass ◽  
Hard Rock ◽  
Compression Fracture ◽  
Field Observations ◽  
Rock Slide ◽  
Mountainous Areas ◽  
Hard Rocks ◽  
Rupture Plane ◽  
Rock Collapse ◽  
Cliff Retreat

Abstract. Calcareous mountainous areas are highly prone to geohazards, and rockslides play an important role in cliff retreat. This study presents three examples of failures of limestone cliffs with sub-horizontal bedding in the southwestern calcareous area of China. Field observations and numerical modeling of Yudong Escarpment, Zengzi Cliff, and Wangxia Cliff showed that pre-existing vertical joints passing through thick limestone and the alternation of competent and incompetent layers are the most significant features for rockslides. A "hard on soft" cliff made of hard rocks superimposed of soft rocks is prone to rock slump, characterized by shearing through the underlying weak strata along a curved surface and backward tilting. When a slope contains weak interlayers rather than a soft basal layers, a rock collapse could occur from the compression fracture and tensile split of the rock mass near the interfaces. A rock slide might shear through a hard rock mass if no discontinuities are exposed in the cliff slope, and sliding may occur along a moderately inclined rupture plane. The "toe breakout" mechanism mainly depends on the strength characteristics of the rock mass.

Interaction of the electromagnetic precursor from a relativistic shock with the upstream flow – II. Induced scattering of strong electromagnetic waves

2019 ◽  
Vol 490 (1) ◽  
pp. 1474-1478 ◽  
Author(s):  
Yuri Lyubarsky
Keyword(s):  
Incident Wave ◽  
Electromagnetic Waves ◽  
Wave Amplitude ◽  
Strong Wave ◽  
Relativistic Shock ◽  
Scattering Rate ◽  
Relativistic Shocks ◽  
Upstream Flow ◽  
Electromagnetic Precursor

ABSTRACT This is the second in the series of papers aiming to study interaction of the electromagnetic precursor waves from relativistic shocks with the upstream flow. Here, I consider the induced scattering of strong waves. In such a wave, the electrons oscillate with relativistic velocities therefore, the scattering generally occurs in harmonics of the incident wave. I show that the induced scattering occurs predominantly in the first harmonics. I also show that even though in the weak case regime, the induced scattering rate is proportional to the intensity of the incident wave, in the strong wave case, the rate decreases as the wave amplitude grows.

Electromagnetic precursor of rock failure

1994 ◽  
Vol 30 (3) ◽  
pp. 238-239
Author(s):  
D. V. Alekseev ◽  
P. V. Egorov
Keyword(s):  
Rock Failure ◽  
Electromagnetic Precursor

scholarly journals Rock collapse on the Bureya River — the year of satellite monitoring

2020 ◽  
Vol 17 (1) ◽  
pp. 271-276
Author(s):  
L.S. Kramareva ◽  
◽  
V.V. Sukhanova ◽  
M.A. Bourtsev ◽  
Yu.A. Amelchenko ◽  
...  
Keyword(s):  
Satellite Monitoring ◽  
Rock Collapse

scholarly journals Fracture mechanism of rock collapse in the freeze-thaw zone of eastern Sichuan-Tibet Mountains under seasonal fluctuating combinations of water and heat

2021 ◽  
Author(s):  
Yong Wu ◽  
Xinpo Li ◽  
Lei Zhu
Keyword(s):  
Hydrostatic Pressure ◽  
Fracture Mechanics ◽  
Freezing Stress ◽  
Collapse Mechanism ◽  
Water Ice ◽  
Freeze Thaw ◽  
Different Seasons ◽  
Rock Collapse ◽  
Thaw Zone ◽  
Eastern Sichuan

Abstract In the freeze-thaw zone of eastern Sichuan-Tibet Mountains, the phases of water in cracks show strong seasonal variations, which significantly affect the stability of perilous rocks in mountains. However, few works have clearly addressed the role of water/ice in crack development from a fracture mechanics viewpoint to explain the seasonality of rock collapse. In this study, we built physical models from a fracture mechanics viewpoint to calculate water-freezing stress, hydrostatic pressure, and their combinations induced by water/ice in cracks, and show the crack propagation mechanism under temperature fluctuations in different seasons in mountainous regions. Based on the models, we calculate fracture conditions, simulate the crack process, and illustrate the rock collapse mechanism in different seasons by the extended finite element method. The results indicate that different phases of water, which induce stress under spatiotemporal fluctuations of temperature, determine the various propagation styles and influence what kind and when a collapse will occur. The collapse of fractured rocks in different seasons generally results from rock damage accumulation owing to the initiation, propagation, and connection of primary cracks under freezing stress or hydrostatic pressure or their different combinations.

scholarly journals Kinetic modeling of the electromagnetic precursor from an axisymmetric binary pulsar coalescence

2019 ◽  
Vol 622 ◽  
pp. A161 ◽  
Author(s):  
B. Crinquand ◽  
B. Cerutti ◽  
G. Dubus
Keyword(s):  
Gravitational Waves ◽  
Kinetic Modeling ◽  
Magnetic Energy ◽  
Magnetic Moments ◽  
High Energy ◽  
Radio Waves ◽  
Particle In Cell ◽  
Rotation Axes ◽  
Fast Radio Burst ◽  
Electromagnetic Precursor

Context. The recent detection of gravitational waves associated with a binary neutron star merger revives interest in interacting pulsar magnetospheres. Current models predict that a significant amount of magnetic energy should be released prior to the merger, leading to electromagnetic precursor emission. Aims. In this paper, we revisit this problem in the light of the recent progress in kinetic modeling of pulsar magnetospheres. We limit our work to the case of aligned magnetic moments and rotation axes, and thus neglect the orbital motion. Methods. We perform global two-dimensional axisymmetric particle-in-cell simulations of two pulsar magnetospheres merging at a rate consistent with the emission of gravitational waves. Both symmetric and asymmetric systems are investigated. Results. Simulations show a significant enhancement of magnetic dissipation within the magnetospheres as the two stars approach one another. Even though the magnetospheric configuration depends on the relative orientations of the pulsar spins and magnetic axes, all configurations present nearly the same radiative signature, indicating that a common dissipation mechanism is at work. The relative motion of both pulsars drives magnetic reconnection at the boundary between the two magnetospheres, leading to efficient particle acceleration and high-energy synchrotron emission. Polar-cap discharge is also strongly enhanced in asymmetric configurations, resulting in vigorous pair production and potentially additional high-energy radiation. Conclusions. We observe an increase in the pulsar radiative efficiency by two orders of magnitude over the last orbit before the merger, exceeding the spindown power of an isolated pulsar. The expected signal is too weak to be detected at high energies even in the nearby universe. However, if a small fraction of this energy is channeled into radio waves, it could be observed as a non-repeating fast radio burst.

ASSESSMENT OF THE CONDITION OF THE ROCK MASSIVE ABOVE THE SUBMERGED SALT MINE ON THE SALT DEPOSIT IN TUZLA IN THE POST-EXPLOITATION PERIOD

2020 ◽  
Author(s):  
Džavid Bijedić ◽  
Samir Hodžić ◽  
Ibrahim Hadžihrustić
Keyword(s):  
Additional Research ◽  
Salt Mine ◽  
Salt Deposit ◽  
Rock Collapse ◽  
B 31

This paper assesses the condition of the "rock massiv" above the closed Tušanj salt mine based on the results of monitoring in the post-exploitation period of the salt deposit in Tuzla. The results of individual monitoring segments realized from 2002 until today, geodetic, hydrogeological, engineering-geological, chemical and geophysical, were analyzed in order to assess the condition of rocks above the mining premises of Tušanj mine, in the rock collapse zone above mine well B-31. The results will be used to assess the condition of the massiv in the post-exploitation period in the Tušanj district and will be the basis for conducting additional research.

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