Soil-water interaction affecting a deep-seated landslide: From field monitoring to experimental analysis

Most deep-seated landslides are characterized by large volumes with deep shear surfaces. They are sensitive to hydrological forcing, especially in climate change scenarios. This paper studies the role of soil-water interaction in affecting the motion of a deep-seated landslide near the southeast coast of China, where seasonal rainfall combined with annual typhoons caused the instability of a previous stable slope. A comprehensive investigation consisting of field monitoring and experiments of soil-water interaction is carried out. The monitoring data show that the landslide exhibits alternate dormant and active stages, corresponding to rainy and dry seasons, respectively. The enduring precipitations predominate the landslide motion, while intensive rainfall brought by typhoon events leads to transient deformation. In addition, wet treatment of intact and reconstituted soils is adopted to mimic the interaction between rainwater and landslide material. The results obtained from in-situ and laboratory direct shear tests indicate that the soil-water interaction is time-dependent. The long-term interaction gives rise to significant strength reduction of soils, thereby regulating the movement of the landslide.

Automated summary

This study investigates the impact of soil-water interaction on the motion of a deep-seated landslide in the southeast coast of China. Through field monitoring and experiments, it is found that continuous rainfall dominates the landslide motion, while intensive rainfall from typhoon events leads to transient deformation. The soil-water interaction is time-dependent, with long-term interaction significantly reducing soil strength and regulating landslide movement.