(1. School of Earth Sciences and Engineering，Nanjing University，Nanjing，Jiangsu 210093，China；2. School of Control Science and Engineering，Shandong University，Jinan，Shandong 250061，China；3. Department of Geotechnical Engineering，Tongji University，Shanghai 200092，China)
Abstract：Fiber optic sensing is a newly-developed distributed monitoring technology；it has great potential in slope engineering. A new method to evaluate the stability condition of slope based on strain distribution of slope mass measured by sensing fiber in real-time is proposed. A slope model test is conducted in laboratory and the Brillouin optical time-domain analysis(BOTDA) technology has been used to measure the horizontal strains at different depths of the slope model subjected to loading on the slope crest. The test results show that the tight-buffering optical fiber packaged by heat-shrinkage tubes can be used for monitoring strain distribution within the slope. In order to take temperature compensation into consideration and achieve the purpose of accurate positioning，the installation of loose fiber sections at key locations along the sensing fiber is recommended. The potential slip surface can be estimated based on the distributed strain monitoring results. The deformation behavior and stability condition of the slope model during testing was analyzed in detail. It is found that there is an empirical relationship between the averaged maximum horizontal strains and the factor of safety of slope，so as to provide a new approach to evaluate slope stability and perform early warning of landslides.
[1] DUNNICLIFF J. Geotechnical instrumentation for monitoring field performance[M]. New York：John Wiley and Sons，1993：546–577.
[2] 朱鸿鹄，殷建华，洪成雨，等. 基于光纤传感的边坡工程监测技术[J]. 工程勘察，2010，38(3)：6–10.(ZHU Honghu，YIN Jianhua，HONG Chengyu，et al. Fiber optic based monitoring technologies of slope engineering[J]. Geotechnical Investigation and Surveying，2010，38(3)：6–10.(in Chinese))
[3] HO Y T，HUANG A B，LEE J T. Development of a fibre Bragg grating sensored ground movement monitoring system[J]. Measurement Science and Technology，2006，17(7)：1 733–1 740.
[4] ZHU H H，HO A N L，YIN J H，et al. An optical fibre monitoring system for evaluating the performance of a soil nailed slope[J]. Smart Structures and Systems，2012，9(5)：393–410.
[5] PEI H F，YIN J H，ZHU H H，et al. Monitoring of lateral displacements of a slope using a series of special fibre Bragg grating-based in-place inclinometers[J]. Measurement Science and Technology，2012，23(2)：1–8.
[6] 丁 勇，施 斌，崔何亮，等. 光纤传感网络在边坡稳定监测中的应用研究[J]. 岩土工程学报，2005，27(3)：338–342.(DING Yong，SHI Bin，CUI Heliang，et al. A fiber optic sensing net applied in slope monitoring based on Brillouin scattering[J]. Chinese Journal of Geotechnical Engineering，2005，27(3)：338–342.(in Chinese))
[7] 隋海波，施 斌，张 丹，等. 边坡工程分布式光纤监测技术研究[J]. 岩石力学与工程学报，2008，27(增2)：3 725–3 731.(SUI Haibo，SHI Bin，ZHANG Dan，et al. Study on distributed optical fiber sensor-based monitoring for slope engineering[J]. Chinese Journal of Rock Mechanics and Engineering，2008，27(Supp.2)：3 725–3 731. (in Chinese))
[8] 李焕强，孙红月，刘永莉，等. 光纤传感技术在边坡模型试验中的应用[J]. 岩石力学与工程学报，2008，27(8)：1 703–1 708.(LI Huanqiang，SUN Hongyue，LIU Yongli，et al. Application of optical fiber sensing technology to slope model test[J]. Chinese Journal of Rock Mechanics and Engineering，2008，27(8)：1 703–1 708.(in Chinese))
[9] 李焕强，孙红月，孙新民，等. 降雨入渗对边坡性状影响的模型实验研究[J]. 岩土工程学报，2009，31(4)：589–594.(LI Huanqiang，SUN Hongyue，SUN Xinmin，et al. Influence of rainfall infiltration on slopes by physical model test[J]. Chinese Journal of Geotechnical Engineering，2009，31(4)：589–594.(in Chinese))
[10] 王宝军，李 科，施 斌，等. 边坡变形的分布式光纤监测模拟试验研究[J]. 工程地质学报，2010，18(3)：325–332.(WANG Baojun，LI Ke，SHI Bin，et al. Simulation experiment for distributed fiber monitoring on deformation of soil slope[J]. Journal of Engineering Geology，2010，18(3)：325–332.(in Chinese))
[11] BERNINI R，MINARDO A，ZENI L. Reconstruction technique for stimulated Brillouin scattering distributed fiber-optic sensors[J]. Optical Engineering，2002，41(9)：2 186–2 194.
[12] 高俊启，张 巍，施 斌. 涂敷和护套对分布式光纤应变检测的影响研究[J]. 工程力学，2007，24(8)：188–192.(GAO Junqi，ZHANG Wei，SHI Bin. Influence of coating and jacket of distributed fiber optic sensor on strain measurement[J]. Engineering Mechanics，2007，24(8)：188–192.(in Chinese))
2013, Vol. 32 
