Items with full text/Total items : 69561/69561 (100%)
Visitors : 23634386
Online Users : 352
Please use this identifier to cite or link to this item:
|Keywords: ||土石流流動形態;地聲;次聲;快速傅利葉;希爾伯特-黃轉換;behavior of debris;geophones;infrasound;Fast Fourier fransform;Hilbert-Huang transform|
|Issue Date: ||2014-10-15 14:28:42 (UTC+8)|
由監測資料顯示次聲之因素主要為風、雨聲，其特徵頻率為5Hz以下。地表逕流與土石流訊號分析得知地聲訊號反應較次聲良好，地表逕流頻譜的主頻分佈會比土石流頻譜高，本次事件地表逕流頻譜特性介於30 ~ 45Hz；土石流頻譜特性則在10 ~ 32Hz間。且藉由影像系統驗證雙聲系統，得知藉由地聲所測得之反應，分析頻譜以及判定訊號反應之延時，以作為土石流預警系統之根據。
;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.
|Appears in Collections:||[土木工程研究所] 博碩士論文|
Files in This Item:
All items in NCUIR are protected by copyright, with all rights reserved.
::: Copyright National Central University. | 國立中央大學圖書館版權所有 | 收藏本站 | 設為首頁 | 最佳瀏覽畫面: 1024*768 | 建站日期：8-24-2009 :::