Evaluation of rock-mass state in Polish copper mines through monitoring the borehole deformations

Orzepowski, S.; Butra, J.

doi:10.1016/j.tecto.2007.06.013

Cited by 4 publications

(3 citation statements)

References 2 publications

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“…These mines exploit a copper-ore seam located at a depth ranging from 600 to 1000 m, which is immediately overlaid by a 100 m thick bed of compact, rigid dolomite. These hard strata over the ore body lead to strain energy accumulation during the extraction works that can be suddenly released inducing very high seismicity (Orzepowski and Butra 2008). The local seismic networks record several thousand seismic events every year, of which between 400 and 700 are strong seismic events (≥ 10 5 J) (Ortlepp 2005).…”

Section: Page 14 Of 48mentioning

confidence: 99%

Intense rockburst impacts in deep underground construction and their prevention

2015

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Deeper excavations have been carried out in both mining and civil engineering projects during the last decades. With the increase of depth, rocks may overstress and rock failures can occur during the excavation. When competent rock strata are encountered under high stress conditions, these failures can vary from superficial spalling to explosive rockburst. Intense rockbursts may cause fatal injuries to workers and significant loss of equipment and time. The occurrence of rockbursts is always difficult to predict and special steps and measures must be taken to control them. First, burst-prone zones must be predicted by an early exhaustive geological study and by the assessment of in situ stress level and orientation. Second, basic design parameters, e.g., shape, size, and excavation method, should be modified and adapted to the expected conditions to minimize rockburst risk. Third, in situ preconditioning methods, e.g., destress blasting, can be applied to decrease the capacity of the rock mass to store energy. Finally, special rock support and reinforcement systems, i.e., yielding systems, must be installated after excavation to ensure the total stability of the opening. The present paper reviews the geological and geomechanical factors which provoke and influence rockbursts in overstressed rock masses and the engineering measures taken to control them.

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Section: Page 14 Of 48mentioning

confidence: 99%

Intense rockburst impacts in deep underground construction and their prevention

2015

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“…According to the modern supporting principle, NATM (New Austrian Tunnelling Method), the key of supporting lies in improving rock's self-supporting ability. It allows occurring appropriate rock deformation to reduce support resistance before causing harmful loose and crushing [7,8,9]. It follows the construction principle "resistance after yield ", generally divided into primary and post supporting two phases.…”

Section: Impact Factors Of Roadway Deformationmentioning

confidence: 99%

Study on Deformation Mechanism of High Stress and Broken Roadway and its Controlling Measures

Liu

Zhang

et al. 2014

AMM

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This paper researched the high press and broken drift deformation mechanism of 1424m filling roadway by theoretical analysis and on-site monitoring. Strengthening rock residual strength by improving roadway pressure contributed to enhancing drift stability. The roadway deformation could be controlled effectively with the method of improving rock self-carrying capacity. The monitoring results showed anchor supporting resistance and reinforcement depth were inadequate. And supporting method was not coordinate with rock deformation, which was the main reason of roadway deformation increasing gradually. Improving bolt pre-stress and increasing the anchoring range are the key to limit roadway deformation. And the support way should provide a greater supporting resistance. It recommends that the combination reinforcing method, "strong prestressed anchor + long cable+ grouting behind the surrounding rock" is appropriate for controlling the drift displacement, and it can save supporting costs 390 yuan per year for per meter drift compared with previous supporting way while reaching the same effect.

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“…Many researchers have made contributions to the monitoring and early warning of rock burst and proposed many kinds of monitoring approaches (e.g., electromagnetic radiation, AE, microseismic signals, and stress) [8][9][10][11][12][13][14][15][16]. The electromagnetic radiation monitoring is an approach that obtains the stress magnitude and variations of coal and rock by monitoring the intensity and pulse of electromagnetic radiation [8].…”

Section: Introductionmentioning

confidence: 99%

Pattern Recognition of Signals for the Fault-Slip Type of Rock Burst in Coal Mines

Liu

Tan

et al. 2015

Shock and Vibration

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The fault-slip type of rock burst is a major threat to the safety of coal mining, and effectively recognizing its signals patterns is the foundation for the early warning and prevention. At first, a mechanical model of the fault-slip was established and the mechanism of the rock burst induced by the fault-slip was revealed. Then, the patterns of the electromagnetic radiation, acoustic emission (AE), and microseismic signals in the fault-slip type of rock burst were proposed, in that before the rock burst occurs, the electromagnetic radiation intensity near the sliding surface increases rapidly, the AE energy rises exponentially, and the energy released by microseismic events experiences at least one peak and is close to the next peak. At last, in situ investigations were performed at number 1412 coal face in the Huafeng Mine, China. Results showed that the signals patterns proposed are in good agreement with the process of the fault-slip type of rock burst. The pattern recognition can provide a basis for the early warning and the implementation of relief measures of the fault-slip type of rock burst.

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Evaluation of rock-mass state in Polish copper mines through monitoring the borehole deformations

Cited by 4 publications

References 2 publications

Intense rockburst impacts in deep underground construction and their prevention

Intense rockburst impacts in deep underground construction and their prevention

Study on Deformation Mechanism of High Stress and Broken Roadway and its Controlling Measures

Pattern Recognition of Signals for the Fault-Slip Type of Rock Burst in Coal Mines

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