Using barometric response functions to estimate unconfined aquifer permeability changes caused by landslide: A case study in southwest China

Abstract

The formation and deformation of landslides lead to continuous variations in the stress-strain state of surrounding rock masses, consequently triggering alterations in aquifer properties. Continuously measuring landslide permeability is challenging, particularly in assessing aquifer properties without human disturbance under natural landslide-induced loads. In this study, continuous measurements of water levels were recorded in a multi-level well within the Kualiangzi landslide area, along with onsite logging of barometric pressures. Barometric response functions were then utilized to estimate the vertical pneumatic diffusivity of the unsaturated zone and the vertical hydraulic diffusivity of the unconfined aquifer for different time periods during the landslide. Slug tests were also conducted to verify permeability changes in the aquifer. Results indicated that in both the unsaturated zone and unconfined aquifer, permeability first increased and then decreased, ultimately doubling and rising 2.3 times, respectively, compared to initial values. The use of barometric response functions represents a novel approach for estimating permeability changes in landslide zones. Due to its cost-effectiveness and convenience, this method proves to be a favorable choice for detecting permeability changes in unconfined aquifers above the sliding surface. It contributes to providing further insights into landslide research.