相敏光时域反射仪土壤振动传播特性

Characteristics of Soil Vibration Propagation Based on Phase Sensitive Optical Time Domain Reflectometers

相敏光时域反射仪(φ-OTDR)广泛应用于管道安全预警、光缆断点查找、清管器定位跟踪等场景,其传感光缆多埋于地下,土壤性质、传输距离、光缆结构等均对信号特征有所影响。本文研究了振动信号在土壤中的传播特性,探究了光缆结构、土壤湿度、传输距离等非事件因素对系统信号特征的影响。此外,从特征频段能量变化趋势的角度,研究了真实冲击振动与非事件性信号波动的区别,并由此提出了一种外部冲击振动的判别方法。

Phase sensitive optical time domain reflectometers(φ-OTDRs) have been widely employed in pipeline safety early warning systems,optical cable break-point searches,mechanical pipeline pig(PIG) positing and tracking,and other fields.The sensing optical cables of φ-OTDRs are mostly buried underground so that the soil characteristics,transmission distances,and optical cable structures all have considerable effects on the signal characteristics.This study considered the propagation characteristics of vibration signals in soils and explored the effects of non-event factors such as optical cable structures,soil moisture,and transmission distances on the signal characteristics of systems.In addition,in terms of energy change trends in characteristic frequency bands,the difference between real shock vibration and non-event signal fluctuations was investigated.A proposed method to judge external shock vibration is derived from the results.