Geoscience Frontiers (Mar 2024)
Probing multi-physical process and deformation mechanism of a large-scale landslide using integrated dual-source monitoring
Abstract
The implementation of isolated heterologous monitoring systems for spatially distant borehole deployments often comes with substantial equipment costs, which can limit the effectiveness of geohazard mitigation and georisk management efforts. To address this, we have developed a novel monitoring system that integrates fiber Bragg grating (FBG) and microelectromechanical system (MEMS) techniques to capture soil moisture, temperature, sliding resistance, strain, surface tilt, and deep-seated inclination. This system enables real-time, simultaneous data acquisition and cross-validation analyses, offering a cost-effective solution for monitoring critical parameters in geohazard-prone areas. We successfully applied this integrated monitoring system to the Xinpu landslide, an active super-large landslide located in the Three Gorges Reservoir Area (TGRA) of China. The resulting strain profile confirmed the presence of two shallow secondary sliding surfaces at depths of approximately 7 m and 12 m, respectively, in addition to the deep-seated sliding surface at a depth of ∼28 m. The lower secondary sliding surface was activated by extreme precipitation, while the upper one was primarily driven by significant changes in reservoir water levels and secondarily triggered by concentrated rainfalls. Anti-slide piles have remarkably reinforced the upper moving masses but failed to control the lower ones. The gap between the pile heads and the soil amplified the rainwater erosion effect, creating a preferential channel for rainwater infiltration. Multi-physical measurements revealed a mixture of seepage-driven and buoyancy-driven behaviors within the landslide. This study offers an integrated dual-source multi-physical monitoring paradigm that enables collaborative management of multiple crucial boreholes on a large-scale landslide, and contributes to the evaluation and improvement of engineering measures in similar geological settings.
