Landslide displacement monitoring is an efficient method to mitigate casualties and economic losses caused by landslide disasters. In recent years, distributed fiber-optic sensing technology, due to distributed and long-distance advantages, was widely used in subsurface displacement monitoring of landslides. However, existing fiber-optic displacement sensors has a large monitoring error when the landslide has multi-sliding surfaces. Aiming at solving this issue, a new joint fiber-optic displacement sensor which can achieve accurate displacement monitoring, was designed. Its measurement error was analyzed and the feasibility was demonstrated by theory and laboratory experiment. Based on the shear lag model, the error caused by strain transfer was studied by fiber-optic cable pull-out experiment. Finally, the feasibility of the sensor was verified by calibration experiment and soil shear experiment. The results show that the displacement sensor has high sensitivity and accuracy, and can realize distributed displacement monitoring inside the slope with multi-sliding surfaces.

滑坡位移监测是减轻滑坡灾害造成的人员伤亡和经济损失的有效方法。近年来，分布式光纤传感技术由于具有分布式和远距离的优势，被广泛应用于滑坡的地下位移监测。然而，现有的光纤位移传感器在滑坡具有多滑面时存在较大的监测误差。针对这一问题，设计了一种新型的光纤关节位移传感器，能够实现精确的位移监测。对其测量误差进行了分析，并通过理论和室内实验论证了其可行性。基于剪力滞模型，通过光缆拉拔实验研究了应变传递引起的误差。最后，通过标定实验和土壤剪切实验验证了传感器的可行性。结果表明，该位移传感器具有较高的灵敏度和准确度，可以实现多滑面边坡内部的分布式位移监测。