Response signal characteristics and processing method for internal mechanical sensor inside pavement structure

ObjectiveThe processing and analysis on high-frequency response signal of mechanical sensor inside pavement is the research focus of the current field scientific observation work of subgrade and pavement. How to obtain the characteristics of real mechanical response signal inside pavement structure is an important basis for determining the mechanical response state of pavement structure and studying the evolution rule of the pavement structure service performance.MethodIn this study, based on the full-scale pavement test loop, the signal characteristics and time-frequency characteristics of dynamic response of pavement structure with two load modes were analyzed for the mechanical response signals inside pavement structure under real vehicle load and FWD drop hammer load. Three common filtering and noise reduction methods based on time domain, frequency domain and wavelet domain were introduced. The effects of running mean, low-pass filtering and wavelet transform on dynamic response signals of pavement were compared. The applicability of different filtering and noise reduction methods were analyzed.ResultThe pavement response signals under continuous real vehicle load and fixed-point FWD drop hammer load have different response characteristics. The signal under fixed-point FWD is more stable and the response waveform is clearer and simpler. Because the FWD load is more instantaneous than the real vehicle load, it is more sensitive to different filtering methods. By comparison, it is found that the selection of running mean steps and low-pass filtering cut-off frequency has great influences on the filtering effect. The wavelet transform filtering noise reduction method has a high degree of reduction and can better reflect the effective characteristics of original signal.ConclusionThe findings can provide technical support for data processing and signal analysis on dynamic mechanical response signals in the field scientific observation of subgrade and pavement.