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| Study on deformation pre-warning of rock slopes based on multi-fractal characteristics of microseismic signals |
| MAO Haoyu1，ZHANG Min1，JIANG Ruochen1，LI Biao2，XU Jian3，XU Nuwen1 |
(1. State Key Laboratory of Hydraulics and Mountain River Engineering，Sichuan University，Chengdu，Sichuan 610065，China；2. School of Geosciences and Technology，Southwest Petroleum University，Chengdu，Sichuan 610500，China； 3. China Three Gorges Corporation，Beijing 100038，China)
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Abstract Based on the rock slope engineering of the left bank of Baihetan hydropower station，Multi-fractal Detrended Fluctuation Analysis (MF-DFA) is used to estimate the multi-fractal spectrum of microseismic waveforms，and the pre-warning signs of rock slope deformation are pointed out on the basis of the time-varying response characteristics of multi-fractal time series of microseismic waveforms. The results show that the multi-fractal characteristics of rock microcracking and blasting waveform time series in the left bank slope are obvious，and that the multi-fractal spectrum width of the blasting waveform is much larger than that of the rock microcracking waveform. Before the slope cracks increase，the multi-fractal time-varying response characteristics of rock microcracking waveforms show strong regularity，which can be viewed as pre-warning signals for deformation. Before the deformation and failure of the rock mass，the multi-fractal spectrum width △α shows an increasing trend while the multi-fractal spectrum of microseismic waveforms △f(α) presents a decreasing trend，which can be regarded as precursor signals of deformation pre-warning. When deformation and failure occur，△α shows a decreasing trend while △f(α) presents an increasing trend，which can be regarded as a deformation failure period. After deformation and failure，both △α and △f(α) show a steady trend and △f(α) as a whole will be near the zero line，which can be regarded as a stable period.
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2020, Vol. 39 
