作者:
Cheng-Cheng Zhang, Hong-Hu Zhu, Su-Ping Liu, Bin Shi, and Gang Cheng
刊物信息:
Canadian Geotechnical Journal
摘要：
Distributed fiber optic sensing (DFOS) is gaining increasing interest in geotechnical monitoring. By using soilembedded fiber optic cables, strain profiles as well as deformation patterns of geotechnical infrastructures can be captured. Probing the fiber optic cable–soil interfacial behavior is vital to the advancement of DFOS-based geotechnical monitoring and our understanding of the soil–inclusion interaction mechanism. To this aim, laboratory pullout tests were performed to investigate the progressive failure of the interface between micro-anchored cables and the surrounding sand. High-resolution strain profiles recorded using Brillouin optical time-domain analysis (BOTDA) not only elucidated the influence of anchorage on strain measurements, but also allowed the classical soil–inclusion interaction problem to be studied in detail. Interfacial shear stresses calculated from step-like strain profiles provided clear evidence of the contribution of each micro-anchor to the pullout resistance. The cable–soil contact is a combination of overall bonding and point fixation depending on the level of mobilized interfacial shear stress, and therefore the validity of measured strains is correlated to a three-stage process of interface failure. This study also shows that installing heat-shrink tubes on the fiber optic cable is a rapid, low-cost, effective approach to make an anchored DFOS system for deformation monitoring of earth structures.
