Department of Engineering, University of Campania "Luigi Vanvitelli", 81031 Aversa, Italy.
Institute for Electromagnetic Sensing of the Environment, Italian National Research Council, 80124 Naples, Italy.
Sensors (Basel). 2021 Oct 23;21(21):7032. doi: 10.3390/s21217032.
This paper shows the results of the monitoring of the deformations of a tunnel, carried out using a distributed optical fiber strain sensor based on stimulated Brillouin scattering. The artificial tunnel of the national railway crosses the accumulation zone of an active landslide, the Varco d'Izzo earthflow, in the southern Italian Apennines. Severely damaged by the landslide movements, the tunnel was demolished and rebuilt in 1992 as a reinforced concrete box flanked by two deep sheet pile walls. In order to detect the onset of potentially dangerous strains of the tunnel structure and follow their time trend, the internal deformations of the tunnel are also monitored by a distributed fiber-optic strain sensor since 2016. The results of the monitoring activity show that the deformation profiles are characterized by strain peaks in correspondence of the structural joints. Furthermore, the elongation of the fiber strands crossing the joints is consistent with the data derived by other measurement systems. Experiments revealed an increase in the time rate of the fiber deformation in the first and last part of the monitoring period when the inclinometers of the area also recorded an acceleration in the landslide movements.
本文展示了使用基于受激布里渊散射的分布式光纤应变传感器对隧道变形进行监测的结果。该人工隧道位于意大利南部亚平宁山脉的瓦科迪伊佐土石流活动堆积区，穿过一条国家铁路。由于受到土石流运动的严重破坏，隧道于 1992 年被拆除重建，采用两侧为深钢板桩墙的钢筋混凝土箱型结构。为了检测隧道结构潜在危险应变的发生并跟踪其时间趋势，自 2016 年以来，隧道的内部变形也通过分布式光纤应变传感器进行监测。监测活动的结果表明，变形曲线的特征是在结构连接处出现应变峰值。此外，穿过连接处的光纤应变的伸长量与其他测量系统得出的数据一致。实验表明，当该地区的测斜仪也记录到土石流运动加速时，在监测期的第一和最后部分，光纤变形的时间率增加。
