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以锦屏一级水电站左岸坝肩边坡微震监测数据为基础,研究蓄水期微震活动性规律,利用S变换(ST)对波形进行分解,并将其应用于左岸坝肩边坡蓄水期与施工期的微震波形处理,以研究其岩石微破裂信号的时频特性。研究表明,(1)微震活动性与地质构造及蓄水活动密切相关,与施工期相比,蓄水期坝肩边坡岩体趋于稳定状态;(2)S变换综合了短时傅里叶变换(STFT)与小波变换(WT)的优点,其在微震等非平稳信号的时频分析中具有独特的优势;(3)时频特性与波形特征相比更加稳定,基于S变换的微震波形分解能较好的揭示波形中包含的震源破坏信息;(4)与施工期相比,左岸坝肩边坡岩石微破裂信号在蓄水期频率升高,持续时间减小,单震型微震事件比例增大,主要是由于在蓄水期左岸坝肩边坡岩体整体性和强度提高,岩体趋于稳定,从而使微震信号表现出不同的时频特征。微震时频参数可以反映岩体的内部微破裂信息,并为其稳定性分析提供参考。
Based on the microseismic monitoring data of the left bank abutment slope of the Jinping I Hydropower Station, the microseismic activity law during the storage period is studied. The waveform is decomposed by S-transform (ST) and applied to the dam bank slope water retention period And the construction of the microseismic waveform processing to study the time-frequency characteristics of rock micro-bursts. The results show that: (1) microseismic activity is closely related to the geological structure and water storage activities. Compared with the construction period, the rock mass at dam shoulder of the reservoir tends to be stable; (2) S transform combines short-time Fourier Leaf transform (STFT) and wavelet transform (WT) have unique advantages in the time-frequency analysis of non-stationary signals such as microseism; (3) the time-frequency characteristics are more stable than the waveform features, and the S-transformed microseism Waveform decomposition can better reveal the source damage information contained in the waveform. (4) Compared with the construction period, the frequency of micro-bursting signal of rocky slope on the left bank abutment shoulder increases with the duration of the reservoir, and the duration of single microseismic event The increase of the ratio is mainly due to the improvement of the integrity and strength of the rock masses and the stability of the rock mass at the dam abutment slope during the storage period so that the microseismic signals show different time-frequency characteristics. The microseismic time-frequency parameters can reflect the internal micro-fracture information of rock mass and provide a reference for its stability analysis.