路面层间应变信号的预处理方法

为获得路面层间应变情况、实时监测道路状态,开发一套无人值守路面层间应变信号自动采集系统。选用四轴货车进行现场试验,对采集的应变信号进行特点分析,通过去除趋势项消除实测信号的零点漂移问题;采用S变换方法研究路面层间应变信号在时域和频域上的分布规律;为提高实测道路应变信号的信噪比,分别采用低通滤波和小波滤波方法对信号进行预处理。研究结果表明:所开发系统可以实现道路应变信号的自动采集;采集的路面层间应变信号的噪声成分频率不固定,而道路应变信号的有效成分主要为50 Hz以下的低频信号;低通滤波方法在处理应变信号时有局限性;小波滤波方法对不同类型的噪声信号都能取得良好的滤波效果,适合路面层间应变信号的预处理。

The pretreatment methods of pavement strain signals

In order to obtain the interlayer strain condition of pavement and monitor the state of the road in real time, an automatic collection system of unattended interlayer strain signal was developed. A four-axle truck was selected for field test to analyze the characteristics of the collected strain signal, and the zero drift of the measured signal was eliminated by removing the trend term. The S variation method was used to study the distribution of interlayer strain signal in time and frequency domain. Finally, in order to improve the signal-to-noise ratio of measured road strain signals, low-pass filtering and wavelet filtering methods were used to preprocess the signals. The results showed that the developed system realized the automatic collection of road strain signal. The noise component frequency of the collected pavement interlayer strain signal was not fixed, and the effective component of the road strain signal was mainly the low-frequency signal below 50 Hz. The low-pass filtering method had limitations in processing strain signal, and wavelet filtering method was suitable for the pretreatment of strain signals between pavement layers for its great filtering effect on different types of noise signals.