| dc.description.abstract | Debris flows from mountainous gulley often cause serious slope disasters, due to the destructive high velocities, larger buried depth and great number of coarse particles. By analyzing the debris flow pattern, its internal particle size and flow speed, we can analyze its impact force on buildings and set up effective prevention and control methods and classify the risk zone to reduce loss. The research employs geophones and acoustic sensors with the CCD-image system built on site to classify the behavior of debris and compare them with geophone signals. At last, it compares and analyzes the correlation between various debris flows and geophone signals.
This paper studies the rainfall-induced debris-flow event at the Houyenshan on May 22, 2013. The current infrasound signals are mainly influenced by winds and rain noises, whose characteristic frequencies are less than 5Hz. Through analyzing signals of surface runoff and debris flows, it can find out that geophone signals are better than infrasound signals for debris-flow monitoring system . Frequency distribution of surface runoff is higher than that of debris-flow the frequency spectrum of surface runoffs are 30 to 45Hz; and the frequency spectrum of debris flows are 10 to 32Hz. Through testing both geophone and acoustic systems by CCD-image system, it can be concluded that the signals of geophone sensors, by frequency spectrum analysis and judging signal duration and their amplitudes can be regarded as the basis of debris-flow warning system.
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