Focal mechanism determination for microseismic events and its application to the left bank slope of the Baihetan hydropower station in China

In order to real time monitor and analyze the rock fracturing due to continuous construction and consolidation at the left slope of Jinping I hydropower station, southwest of China, a microseismic monitoring system was conducted and an optimal design for the sensor arrays was investigated. The sensor array was designed on the basis of P method and Powell algorithm. The artificial fixed blasting tests were applied to adjust the positioning accuracy of the monitoring system. The results show that the location error of seismic source is less than 12 m in the scope of the sensor array, which demonstrates the monitoring system has high positioning g accuracy. The contour of source location shows that the location errors near the main tunnels at the left bank slope is below 6 m. Signals from 689 microseismic events with moment magnitude ranging from -2.1 to -0.2 were recorded during the first year monitoring period from June 15, 2009. The spatial distribution of microseismicity can identify and delineate the potential failure at the left bank slope, which provides some references for the future excavation and consolidation of the hydropower station.

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Microseismic monitoring and stability analysis of the left bank slope in Jinping first stage hydropower station in southwestern China

International Journal of Rock Mechanics and Mining Sciences ◽

10.1016/j.ijrmms.2011.06.009 ◽

2011 ◽

Vol 48 (6) ◽

pp. 950-963 ◽

Cited By ~ 108

Author(s):

N.W. Xu ◽

C.A. Tang ◽

L.C. Li ◽

Z. Zhou ◽

C. Sha ◽

...

Keyword(s):

Stability Analysis ◽

Microseismic Monitoring ◽

Southwestern China ◽

Hydropower Station ◽

Left Bank ◽

Bank Slope

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Mechanism of deep cracks in the left bank slope of Jinping first stage hydropower station

Engineering Geology ◽

10.1016/j.enggeo.2003.12.005 ◽

2004 ◽

Vol 73 (1-2) ◽

pp. 129-144 ◽

Cited By ~ 47

Author(s):

Shengwen Qi ◽

Faquan Wu ◽

Fuzhang Yan ◽

Hengxing Lan

Keyword(s):

Hydropower Station ◽

Left Bank ◽

Bank Slope

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Stability Analysis of the Left Bank Slope of Baihetan Hydropower Station Based on the MF-DFA Method

Advances in Civil Engineering ◽

10.1155/2020/8898318 ◽

2020 ◽

Vol 2020 ◽

pp. 1-19

Author(s):

Haoyu Mao ◽

Min Zhang ◽

Biao Li ◽

Nuwen Xu

Keyword(s):

Rock Mass ◽

Multifractal Spectrum ◽

Surrounding Rock ◽

Left Bank ◽

Deformation And Failure ◽

Bank Slope ◽

Spectrum Width ◽

Baihetan Hydropower Station ◽

Rock Mass Deformation ◽

Mass Deformation

Based on the left bank slope of Baihetan hydropower station in Southwestern China, a high-precision microseismic monitoring system was established. An early warning model of surrounding rock mass deformation and failure based on MF-DFA was proposed. The results showed that the multifractal characteristics of the microseismic and blasting waveform time series in the left bank slope were obvious, and the multifractal spectrum width of the blasting waveform is much larger than that of microseismic waveform. Before the slope cracks increased, the multifractal time-varying response characteristics of microseismic waveform showed strong regularity, which could be regarded as a precursor of surrounding rock mass deformation. Before the deformation and failure of surrounding rock mass, the multifractal spectrum width Δα showed an increasing trend while the multifractal spectrum of microseismic waveforms Δf(α) presented a decreasing trend, which can be regarded as a precursor of surrounding rock mass deformation; when deformation and failure occurred, Δα showed a decreasing trend and Δf(α) showed an increasing trend, which can be regarded as a deformation failure period; after the occurrence of deformation and failure, both Δα and Δf(α) showed a steady trend, and Δf(α) would approach to the zero line, which can be regarded as a stable period.

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