Interfacial characterization of soil-embedded optical fiber for ground deformation measurement

Recently fiber-optic sensing technologies have been applied for performance monitoring of geotechnical structures such as slopes, foundations, and retaining walls. However, the validity of measured data from soil-embedded optical fibers is strongly influenced by the properties of the interface between the sensing fiber and the soil mass. This paper presents a study of the interfacial properties of an optical fiber embedded in soil with an emphasis on the effect of overburden pressure. Laboratory pullout tests were conducted to investigate the load-deformation characteristics of a 0.9 mm tight-buffered optical fiber embedded in soil. Based on a tri-linear interfacial shear stress-displacement relationship, an analytical model was derived to describe the progressive pullout behavior of an optical fiber from soil matrix. A comparison between the experimental and predicted results verified the effectiveness of the proposed pullout model. The test results are further interpreted and discussed. It is found that the interfacial bond between an optical fiber and soil is prominently enhanced under high overburden pressures. The apparent coefficients of friction of the optical fiber/soil interface decrease as the overburden pressure increases, due to the restrained soil dilation around the optical fiber. Furthermore, to facilitate the analysis of strain measurement, three working states of a soil-embedded sensing fiber were defined in terms of two characteristic displacements.

[1]  T. Horiguchi,et al.  BOTDA-nondestructive measurement of single-mode optical fiber attenuation characteristics using Brillouin interaction: theory , 1989 .

[2]  Bin Shi,et al.  Application of a distributed optical fiber sensing technique in monitoring the stress of precast piles , 2012 .

[3]  Wei Jin,et al.  Monitoring Internal Displacements of a Model Dam Using FBG Sensing Bars , 2010 .

[4]  Liu Xu-min,et al.  多スロープ応答及び画像再構成アルゴリズムを用いる高ダイナミックレンジ相補性金属‐酸化物‐半導体(CMOS)カメラ , 2009 .

[5]  Zuyu Chen,et al.  Distributive monitoring of the slope engineering , 2008 .

[6]  Ke Li,et al.  Test on application of distributed fiber optic sensing technique into soil slope monitoring , 2009 .

[7]  M. Barnoski,et al.  Fiber waveguides: a novel technique for investigating attenuation characteristics. , 1976, Applied optics.

[8]  K. Krebber,et al.  Fiber-optic sensor applications in civil and geotechnical engineering , 2011 .

[9]  E. Bourgeois,et al.  Soil-embedded optical fiber sensing cable interrogated by Brillouin optical time-domain reflectometry (B-OTDR) and optical frequency-domain reflectometry (OFDR) for embedded cavity detection and sinkhole warning system , 2009 .

[10]  Jie Han,et al.  Behavior of Interfaces between Fiber-Reinforced Polymers and Sands , 1999 .

[11]  Bin Shi,et al.  Interfacial shear strength of fiber reinforced soil , 2010 .

[12]  Bin Chen,et al.  A Feasibility Study on the Application of Fiber-Optic Distributed Sensors for Strain Measurement in the Taiwan Strait Tunnel Project , 2003 .

[13]  Zhang Jie,et al.  Distributed Fiber Optic Monitoring and Stability Analysis of a Model Slope under Surcharge Loading , 2014 .

[14]  Liang Ren,et al.  Strain Transfer Coefficient Analyses for Embedded Fiber Bragg Grating Sensors in Different Host Materials , 2009 .

[15]  Jian-Hua Yin,et al.  An optical fibre monitoring system for evaluating the performance of a soil nailed slope , 2012 .

[16]  Victor Elias,et al.  Friction in Reinforced Earth , 1979 .

[17]  K. Shimizu,et al.  Development of a distributed sensing technique using Brillouin scattering , 1995 .

[18]  Libo Yuan,et al.  Investigation of a coated optical fiber strain sensor embedded in a linear strain matrix material , 2001 .

[19]  Rodrigo Salgado,et al.  Measurement of pile load transfer using the Fiber Bragg Grating sensor system , 2004 .

[20]  Libo Yuan,et al.  Sensitivity coefficient evaluation of an embedded fiber-optic strain sensor , 1998 .

[21]  John Dunnicliff,et al.  Geotechnical Instrumentation for Monitoring Field Performance , 1988 .

[22]  Dong-Mei Zhang,et al.  Impact of overhead excavation on an existing shield tunnel : field monitoring and a full 3D finite element analysis , 2013 .

[23]  Michel LeBlanc.  Study of interfacial interaction of an optical fibre embedded in a host material by in situ measurement of fibre end displacement—Part 2. Experiments , 2005 .

[24]  K. Y. Yong,et al.  PULL-OUT RESISTANCE MECHANISM OF A SOIL NAIL REINFORCEMENT IN DILATIVE SOILS , 2000 .

[25]  Alessandro Airoldi,et al.  Characterization of the interface between composites and embedded Fiber Optic sensors or NiTiNOL wires , 2011 .

[26]  Bin Shi,et al.  Jacket effect on strain measurement accuracy for distributed strain sensors based on Brillouin scattering , 2006 .

[27]  Chuan Li,et al.  Monitoring pressure and thermal strain in the second lining of a tunnel with a Brillouin OTDR , 2006 .

[28]  Yun Bai,et al.  A novel method of embedding distributed optical fiber sensors for structural health monitoring , 2011 .

[29]  An-Bin Huang,et al.  Development of a fibre Bragg grating sensored ground movement monitoring system , 2006 .

[30]  K. Soga,et al.  Monitoring Twin Tunnel Interaction Using Distributed Optical Fiber Strain Measurements , 2012 .

[31]  Christopher K.Y. Leung,et al.  Debonding and Calibration Shift of Optical Fiber Sensors in Concrete , 2000 .

[32]  Zhishen Wu,et al.  Performance of a BOTDR optical fibre sensing technique for crack detection in concrete structures , 2008 .

[33]  Gangbing Song,et al.  Recent applications of fiber optic sensors to health monitoring in civil engineering , 2004 .

[34]  Nicholas Ioannides,et al.  Approaches to mitigate polymer-core loss in plastic optical fibers: a review , 2014 .

[35]  Hiroshi Naruse,et al.  River Levee Change Detection Using Distributed Fiber Optic Strain Sensor (Special Issue on Optical Fiber Sensors) , 2000 .

[36]  R. Bernini,et al.  Distributed Sensing at Centimeter-Scale Spatial Resolution by BOFDA: Measurements and Signal Processing , 2012, IEEE Photonics Journal.

[37]  Albert T. Yeung,et al.  Field Pullout Testing and Performance Evaluation of GFRP Soil Nails , 2011 .

[38]  F. Ansari,et al.  MECHANICS OF BOND AND INTERFACE SHEAR TRANSFER IN OPTICAL FIBER SENSORS , 1998 .

[39]  Michael Iten,et al.  Novel Applications of Distributed Fiber-optic Sensing in Geotechnical Engineering , 2011 .

[40]  K. Hill,et al.  Photosensitivity in optical fiber waveguides: Application to reflection filter fabrication , 1978 .

[41]  Gangbing Song,et al.  Strain transferring analysis of fiber Bragg grating sensors , 2006 .

[42]  Guanglun Wang,et al.  Elasto-plastic bond mechanics of embedded fiber optic sensors in concrete under uniaxial tension with strain localization , 2003 .

[43]  Markus Aufleger,et al.  Development of an integral system for dam and landslide monitoring based on distributed fibre optic technology. , 2008 .

[45]  Hong-hu Zhu,et al.  Monitoring of lateral displacements of a slope using a series of special fibre Bragg grating-based in-place inclinometers , 2012 .