Rockburst prediction and stability analysis of the access tunnel in the main powerhouse of a hydropower station based on microseismic monitoring

Xue, Ruixiong; Liang, Zheng Zhao; Xu, Nuwen; Dong, Linlu

doi:10.1016/j.ijrmms.2019.104174

Cited by 65 publications

(21 citation statements)

References 12 publications

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“…Apparent volume denotes the volume of the rock mass in the inelastic deformation zone of the seismic source, which could be calculated from the recorded waveform parameters. The cumulative apparent volume was commonly used to characterize the degree of rock deformation, which could be expressed by the following formula [31][32][33][34],…”

Section: Characteristics Of Apparent Volume and Energy Indexmentioning

confidence: 99%

Research on Structural Evolution and Microseismic Response Characteristics of Overlying Strata during Repeated Mining of Steeply Inclined and Extra Thick Coal Seams

Lai¹,

Yang²,

Zhang³

et al. 2021

Lithosphere

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Repeated mining is the main factor that leads to development, propagation, and eventual deformation of the overlying strata fissures in the steeply inclined and extra thick coal seams (SIETCS). The evolution of the overlying strata structure is closely related to microseismic events in a mine. As the mining depth increases, the evolution rules of the overlying strata structure become more complicated and can easily induce dynamic disaster accidents. To solve these problems, this paper established a physical similarity simulation model. Microseismic monitoring equipment was used to study the relationship between the evolution of the overlying strata structure and the energy-frequency of microseismic events. On the basis of the principle of quantitative seismology, the response relationship between the overlying strata structure and the microseisms at different mining stages was compared and analyzed from a quantitative perspective. The characteristics of cumulative apparent volume, energy index, and microseismic b value were used to reveal the precursor characteristics of overburden instability and failure. The results showed that due to the occurrence characteristics of coal seam, the distribution characteristics of rock stratum stress, and the effects of mining disturbances, the energy accumulation-release period after instability failure of the overlying strata induced by shallow mining was longer than the energy accumulation-release period induced by deep mining. And the deep coal and rock mass had a periodic “balance-instability-rebalance-instability again” dynamic evolution process under the disturbance of repeated mining. In the working face mining, the slope of the accumulative apparent volume ΣVA curve suddenly increased, and the energy index EI gradually decreased at the late peak period, which indicated the deformation and failure of overburden. However, the b value of the microseismic event presented the precursory characteristics of rock stratum fracture that gradually increased and then changed drastically.

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Section: Characteristics Of Apparent Volume and Energy Indexmentioning

confidence: 99%

Research on Structural Evolution and Microseismic Response Characteristics of Overlying Strata during Repeated Mining of Steeply Inclined and Extra Thick Coal Seams

Lai¹,

Yang²,

Zhang³

et al. 2021

Lithosphere

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“…Therefore, in the early warning of rockbursts, the type of rockburst can be judged in advance by analyzing the proportion of events of different fracture types, for a more accurate early warning. Xue et al [47] used the energy ratio method to study the formation process of rockbursts in underground caverns and found that the E S /E P value of microseismic events before a rockburst tends to decrease evidently, that is, the proportion of tensile failure events before the rockburst increases significantly. Therefore, the rockburst can be predicted by the change in the proportion of different failure types in the process of rockburst formation.…”

Section: Structure-type Rockburstmentioning

confidence: 99%

“…Laboratory studies, field observations, and numerical simulations have shown that the slope of the distribution curve is related to the stress condition and reflects the degree of microfracture activity in the rock mass. In the process of surrounding rock excavation and unloading, when the large-scale fracture in the rock mass increases gradually, the b value evidently decreases [47,60]. Because it can directly reflect the stability of a surrounding rock, the b value is often considered an important early warning index for rockbursts.…”

Section: B Valuementioning

confidence: 99%

Review on Early Warning Methods for Rockbursts in Tunnel Engineering Based on Microseismic Monitoring

et al. 2021

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Due to the different geological conditions and construction methods associated with different projects, rockbursts in deep-buried tunnels often present different precursor characteristics, bringing major challenges to the early warning of rockbursts. To adapt to the complexity of engineering, it is necessary to review the latest advancements in rockburst early warning and to discuss general early warning methods. In this article, first, microseismic monitoring and localization methods applicable under tunneling construction are reviewed. Based on the latest engineering examples and research progress, the microseismic evolution characteristics of the rockburst formation process are summarized, and the formation process and mechanism of structure-type and delayed rockbursts are analyzed. The different methods for predicting the risk and level of rockbursts using microseismic indices are reviewed, and the implementation methods and application cases for predicting potential rockburst areas and rockburst probability based on a mechanical model are expounded. Finally, combined with the new practice in early warning methods, development directions for the early warning of rockbursts are put forward.

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“…Microseism, a technology by receiving the elastic wave in the process of fracture and deformation of coal and rock, has a wide range of monitor in space and time and has wide application in rockburst prediction. By comprehensive analysis of the received waveform and a series of source parameters [21][22][23][24][25], the location, time, energy, and even the failure form of rock mass of the microseism can be obtained, thus profoundly revealing the whole process of the rockburst from its initiation to outbreak. e purpose of this paper is to discuss the influence of the residual pillars and fault on the mining of the lower coal seam.…”

Section: Introductionmentioning

confidence: 99%

Numerical and Field Investigations on Rockburst Risk Adjacent to Irregular Coal Pillars and Fault

Zhang³

et al. 2021

Shock and Vibration

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Irregular coal pillars are often reserved in the upper coal seam in multiseam mining due to the limitation of geological conditions and mining methods. Diffused and transmitted stress in the pillars will form the stress concentrated areas in the lower coal seam and will increase the risk of rockburst. Based on the upper irregular pillars and fault encountered in the 7301 working face of the Zhaolou coal mine, this paper studies the evolution of stress and energy when the working face passed through the area affected by pillars. The adopted methods include numerical simulations and field monitoring. The change in stress concentration factor and stress gradient because of the mining activities in lower coal seam was analyzed by numerical simulation, indicating that the stress gradient reaches a peak when the working face is closed to the area under the edge and junction of pillars, which has the high risk of inducing rockburst. The sources’ location, variation rule of microseismic (MS) total energy and events, frequency spectrum distributions, and source parameters are discussed, respectively, based on the field monitoring data. The main conclusions were obtained as follows: (1) The total energy and event counts reach the peak when working face is close to the area under the edge and the junction of pillars. (2) The dominant frequency transfers from high frequency to low frequency, the stress drop reaches the peak value, the energy index decreases sharply, and the cumulative apparent volume increases sharply, which all are obvious precursory characteristics before rockburst.

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Rockburst prediction and stability analysis of the access tunnel in the main powerhouse of a hydropower station based on microseismic monitoring

Cited by 65 publications

References 12 publications

Research on Structural Evolution and Microseismic Response Characteristics of Overlying Strata during Repeated Mining of Steeply Inclined and Extra Thick Coal Seams

Research on Structural Evolution and Microseismic Response Characteristics of Overlying Strata during Repeated Mining of Steeply Inclined and Extra Thick Coal Seams

Review on Early Warning Methods for Rockbursts in Tunnel Engineering Based on Microseismic Monitoring

Numerical and Field Investigations on Rockburst Risk Adjacent to Irregular Coal Pillars and Fault

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