基于次声监测的泥石流定位方法研究

Observations and studies show that, the formation and movement of debris flow willgenerate infrasonic signals. Infrasound has characteristics of strong penetrating power and weak attenuation , and its propagation speed is greater than thevelocity of debris flow, so infrasound has been applied to the monitoring and early warning of debris flow. However, the method of infrasound monitoring of debris flow is not accurate and timely, because of the interference of various natural or man-made noise to reduce the alarm accuracy, but also can only monitor whether debris flow happened nearby, so which is not able to determine the location of debris flow happened .This study is based on the research of debris flow of infrasound and environmental interfere infrasonic characteristics, to establish key feature library of debris flow infrasound and typical interference of infrasound, and research the analysis method of multichannel infrasonic signal correlation based on sensor array. According to the spectral characteristics and time zone distribution difference between the target signal and the interference signal, to research infrasound signal recognition of debris flow. On this basis, according to the mountainous terrain characteristics and the propagation law of infrasound, research and analysis the best method of debris flow infrasonic monitoring array deployment, and combined with GIS technology to establish the algorithm model of debris flow infrasonic source localization, to estimate accurately position of debris flow happened, achieve more effective debris flow warning accordingly.

观测研究表明，泥石流的形成和运动会产生次声信号，次声具有穿透力强和衰减弱的特性，且其传播速度远大于泥石流的运动速度，因此次声已被应用于泥石流监测预警中。但目前的泥石流次声监测预警方法不仅因为各类自然或人为噪声的干扰，降低了报警准确率，而且也仅能监测到附近是否发生了泥石流，无法判断泥石流发生的位置。本课题拟在研究泥石流次声与环境干扰次声特征的基础上，建立泥石流次声与典型干扰次声的关键特征库，并研究基于传感器阵列的多通道次声信号相关性分析方法，根据目标信号与干扰信号的频谱特征及时域分布差异，研究泥石流次声信号的识别方法。在此基础上，根据山区的地形特征和次声波的传播规律研究最佳的泥石流次声监测阵列部署方法，并结合GIS技术建立泥石流次声声源定位算法模型，对泥石流灾害的发生位置进行估算，据此实现更为有效的泥石流预警。

泥石流是含有大量泥砂石块的特殊洪流，在山区沟谷中由暴雨等水源激发，具有极大的危害性。观测研究表明，泥石流的形成和运动会释放出次声波（声波频率≤20Hz）,由于次声波在空气中的传播速度远大于泥石流运动速度，通过对泥石流次声的监测和定位将有助于泥石流灾害临灾预警。.为捕获泥石流激发的次声信号，本文首先对泥石流次声采集系统的构建方案进行了设计与测试，并对泥石流次声信号的特征及处理方法进行了描述，通过研究泥石流次声与环境噪声的差异，制定了泥石流次声的判识流程；基于上述研究构建了次声传感器阵列，采用时间同步的多传感器采集系统采集并回传次声信号，利用次声信号的互相关性分检出各传感器采集到的同一时刻泥石流发出的次声信号，并计算该信号到达各传感器的时延，利用时延和传感器阵列坐标计算次声声源位置，从而实现泥石流灾害的监测与定位。经过在中国科学院东川泥石流观测研究站的实地测试，该方法能准确地监测到泥石流发生，并能较为准确地确定泥石流位置。本项研究对泥石流次声信号的辨识以及非接触式的泥石流监测预警研究都具有较好的实用价值。