基于声波频谱特征的土体障碍物超声探测分析

Analysis of Ultrasonic Detection of Obstacles in Soil Based on Acoustic Spectrum Characteristics

为了探究超声波法对土体中障碍物的探测效果,以上海市某地区的黏性土为介质设计了室内试验,并通过改变土的含水率和超声探测距离来研究不同因素对超声探测效果的影响。通过傅里叶变换对试验结果进行频谱特征分析,分别从含水率、探测距离、障碍物三个方面分析不同影响因素下接收信号的频谱变化规律。研究结果表明:随着含水率的增大,接收信号的频谱畸变程度减小,曲线上的突变点减少;随着探测距离的增大,接收信号的频谱畸变程度增大,曲线上的突变点增多;在含水率较低的情况下,障碍物的存在对接收信号频谱的影响忽略不计,在含水率较高的情况下,障碍物的存在会导致接收信号的频谱畸变程度增大,可以从频谱上进行识别。

In order to explore the detection effect of ultrasonic method on the obstacles in soil,an indoor experiment is designed by using the cohesive soil in an area of Shanghai as the medium.The influence of different factors on the ultrasonic detection effect is studied by changing the soil moisture content and ultrasonic detection distance.The experimental results are analyzed for the spectral characteristics by using Fourier transform.The spectral changes of the received signals are analyzed from three aspects of moisture content,detection distance and obstacle to investigate the effects of various influencing factors.The research results show that with the increase of moisture content,the degree of distortion in the received signal spectrum decreases,and the number of abrupt changes on the curve decreases.With the increase of detection distance,the degree of distortion in the received signal spectrum increases,and the number of abrupt changes on the curve increases.When the moisture content is low,the presence of obstacles has the negligible effects on the received signal spectrum.However,when the moisture content is high,the presence of obstacles can cause an increase in the degree of distortion in the received signal spectrum,which can be recognized from the spectrum analysis.