Assessment of slope instability with effects of critical displacement by using InSAR and FEM

Abstract

A good knowledge of the mechanism of slope failure in open-cast mines can be understood by evaluating the intrinsic and extrinsic factors and their interactions in causing slope instability, and by gathering displacement information from periodical monitoring. Surface deformations, caused by mining activities at mine sites, are conventionally measured by using survey instruments such as levels, theodolites, total stations, GPS receivers, and photogrammetric cameras. However, conventional long-term monitoring techniques are insufficient due to unfavorable factors such as topographic structure and flora of the observation, urbanization rate, and time delays in obtaining results. Due to this fact that the Interferometric Synthetic Aperture Radar (InSAR) technique has become prominent in recent years as a method that uses satellite data to enable the detection of surface deformations and movements especially in very large areas. In this study, the mechanism of slope failure accurately detected by way of associating mechanical and physical information of the slopes with time-dependent deformation behavior (time series analysis) by periodically monitoring of displacements at the benches of a lignite open pit that experienced interruptions of production due to slope failures. Mining area has been periodically monitored by InSAR and data consisting of the time-dependent behavior of the deformations were correlated with the mechanical and physical property data that were obtained from back analysis of slope failure using finite elements method (FEM) approximation. In this context, a dynamic method was proposed that can predict the failure risk of the slopes at the site before the critical displacement values are not reached.