###### Abstract
[PERSON] et al. [7] studied a slowly moving loess slope using the HDR method to identify its mechanically weak areas, predict future rupture surfaces, and depict the danger zones. [PERSON] et al. [8] used the high-density electrical method to detect the landslide body in Xiaozhuang Village, Changjahe Town, to explore the stratigraphic structure, thickness of the landslide body, groundwater distribution, and spatial spreading of the landslide area. [PERSON] et al. [9] used the high-density electrical method to detect a typical loess seismic landslide in the southwestern mountainous area of Xiji County, Ningxia, then verified and analyzed it with drilling data to identify the characteristics of the stratigraphic structure, loess thickness, bedrock burial depth, water-rich section, and spatial spreading in the landslide area. [PERSON] et al. [10] used the HDR method to probe the overburden thickness, karst cavities, and sliding zone locations in the mine area of Nanhengzhen to delineate the stratigraphic lithology and limestone distribution zones. [PERSON] et al. [11] carried out HDR measurements on weathered basal slopes of medium and fine-grained granitic rocks in the Sungai Ara area of the Penang hills, and six HDR profiles were obtained at different elevations of the slope sites. [PERSON] et al. [12] performed a geophysical survey combined with seismic refraction tomography (SRT), seismic scattered wave imaging (SSI), and high-density resistivity (HDR) along five profiles over the landslide body. [PERSON] and [PERSON] [13] used the Wenner device to detect the slope of Huangming Reservoir in Yuyao City, analyze the weathering degree of rock, and evaluate the stability of the slope. [PERSON] et al. [14] used GPR and HDR geophysical methods to probe the slope at different times and observed changes in the geophysical profiles over time. The results demonstrated the processes where a significant expansion of wet areas inside both studied rock masses is associated with the logging operations. [PERSON] et al. [15] used the HDR method to detect the Baijjahoa landslide and derived the water content based on the inversion of the resistivity model. [PERSON] et al. designed [16] a physical model of a rainfall-affected slope and used the HDR method to measure the apparent resistivity of the slope rock and soil mass at different rainfall times to analyze the formation process of internal disaster sources of the rainfall-affected slope. Physical detection methods, such as HDR and GPR, can identify geological structures and help preliminarily determine the engineering geological structure of slope rock and soil mass. Based on an analysis of the overall geologic structure of the slope, sensors buried inside the slope can continuously monitor the movement of the geotechnical mass and provide dynamic monitoring data over time. In recent years, FBG sensors have been widely applied in the field of geotechnical engineering because of their ability to resist electromagnetic interference, high accuracy, online monitoring, and multiplexing compared to traditional sensors. Many researchers [17; 18] have combined borehole-based deep displacement monitoring methods with FBG strain sensors for slope stability monitoring. [PERSON] et al. [19] developed a monitoring system with a borehole inclinometer using FBG as a strain sensor to monitor artificial slope deformation for four months during the construction term. The monitoring system worked properly and the availability of the FBG borehole inclinometer was proved. [PERSON] et al. [20] present a monitoring system consisting of FBG-based in-place inclinometers for monitoring movements of landslides and have installed the FBG-based in-place inclinometers at a site in Weijiagou Valley, China. [PERSON] et al. [21] proposed an easy-mounting sensor structure containing several inclinometer casings and a series of flexible pipes with FBGs connected to each other. The FBG deformation sensors have been installed in a slope, and a matched monitoring station has been established and operated. [PERSON] et al.