吴涵,朱鸿鹄,周谷宇,等.2020.考虑变形协调的土体剪切位移分布式测试研究[J].工程地质学报,28(4):716-724.doi:10.13544/j.cnki. jeg.2019-203 .
    引用本文: 吴涵,朱鸿鹄,周谷宇,等.2020.考虑变形协调的土体剪切位移分布式测试研究[J].工程地质学报,28(4):716-724.doi:10.13544/j.cnki. jeg.2019-203 .
    Wu Han,Zhu Honghu,Zhou Guyu,et al.2020.Experimental study on distributed monitoring of soil shear displacement considering deformation compatibility[J].Journal of Engineering Geology,28(4):716-724.doi: 10.13544/j.cnki.jeg.2019-203.
    Citation: Wu Han,Zhu Honghu,Zhou Guyu,et al.2020.Experimental study on distributed monitoring of soil shear displacement considering deformation compatibility[J].Journal of Engineering Geology,28(4):716-724.doi: 10.13544/j.cnki.jeg.2019-203.

    考虑变形协调的土体剪切位移分布式测试研究

    EXPERIMENTAL STUDY ON DISTRIBUTED MONITORING OF SOIL SHEAR DISPLACEMENT CONSIDERING DEFORMATION COMPATIBILITY

    • 摘要: 岩土体的剪切破坏是地质工程领域较为常见的诱灾机制,岩土剪切变形的监测对于岩土工程防灾减灾至关重要。光纤传感技术因其可实现高灵敏度的分布式应变监测,成为获取岩土剪切位移信息的潜在手段之一。本文利用全分布式光频域反射(OFDR)技术及粒子图像测速(PIV)技术,开展了土体剪切位移监测可行性的试验研究。在充分考虑直埋式应变传感光缆和周围土体变形协调的基础上,探究了剪切试验中光缆应变测值与土体剪切位移之间的关联,并提出了实现两者转换的光纤应变积分法。试验结果显示:在光缆和土体耦合良好的阶段,光缆伸长计算值与土体剪切位移之间存在线性关系,使用高精度、高空间分辨率的OFDR技术监测土体剪切位移具备可行性;在光缆上布设管式锚固点或提高围压可以增加光缆和土体的耦合性能,进而获得更好的剪切位移监测效果。

       

      Abstract: The shearing failure of rock and soil masses is reckoned as a common trigger for geohazards, and it is therefore a critical issue to monitor the shear displacements of rock and soil for disaster prevention and mitigation in geotechnical engineering. Fiber optics sensing technology can be potentially used for shear displacements monitoring owing to its high sensitivity and distributed strain sensing(DSS)features. In this paper, we carried out an experimental study to investigate the feasibility of soil shear displacements based on the fully distributed Optical Frequency Domain Reflection(OFDR) and Particle Image Velocimetry(PIV)technologies. Taking into account the deformation compatibility of directly embedded optical fiber cables and the surrounding soil, the relationship between the distributed strain measurements and real soil shear displacements is explored, and we proposed the strain integral method to realize the conversion. The test results show that while the optical fiber cables are well coupled with soil, there is a linear relationship between the calculated elongation and soil shear displacements, indicating that it is feasible to use the high-accuracy and high-spatial resolution OFDR technology to monitor soil shear displacements. Installing tube-type anchorages on optical fiber cables or increasing the confining pressure can effectively enhance the soil-cable coupling capability, and help to obtain more reliable shear displacement measurements.

       

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