Physical modeling of land subsidence due to underground cavity and its monitoring by electrical resistivity survey in geotechnical centrifuge

Abstract

Hazardous sinkholes started to emerge as a new problem that threatens the safety of the people in Korea. In this study, sinkhole simulation and monitoring in centrifuge test were designed to make environment for related research. Electrical resistivity monitoring system was built in centrifuge facility and 1g preliminary test was performed using ice blocks in order to ensure the simulation of underground cavities in centrifuge model. Subsequently, 20g centrifuge test was performed simulating two types of underground cavities such as existing cavity and water leakage from sewage pipeline. After reaching target centrifugal g-level, groundwater was injected from the base of model box to simulate the groundwater level change. Electrical resistivity survey was conducted continuously to monitor the underground anomalies. The electrical resistivity results from the centrifuge test corresponds well to expected process of sinkhole generation by showing the definite resistivity difference between underground cavities and adjacent soils. From the underground cavity simulation in centrifuge, it is noticed that electrical resistivity survey could monitor the process of underground cavity generation effectively, and developed monitoring system can be applied to further the parametric studies in sinkhole research.