Hyuk-Sang Jung

A study on using acoustic emission in rock slope with difficult ground — focused on rainfall

This study attempted to predict slope failures by applying AE techniques to a rock slope with a history of collapse. Damage levels were assessed on the basis of the AE characteristics estimated by conducting laboratory tests on simulated slope failures. The test results showed that the specimen showed a very high degree of failure at the initial stage of loading, which was analyzed using the AE characteristics to assess the damage levels. The variation in the measured number of AE hits and AE events in field tests may indicate minute variations in the slope. The measured values appeared to be insignificant as they were less than the minimum criterion for damage. An analysis of rainfall, which is an important factor in slope behavior, showed that as rainfall increased, the number of AE hits and AE events also increased. In particular, when the cumulative rainfall was constant, the cumulative number of AE hits and AE events appeared to converge, indicating that the cumulative rainfall and the number of AE hits are closely connected. When applying AE techniques to a slope that has a high probability of failure, the failure prediction of the specific location and the early prediction of failure behavior on rock slopes became possible.

Investigation of ground behaviour adjacent to an embedded pile according to various tunnel volume losses

The rapid development of urban areas due to population and infrastructure growth has led to increased traffic congestion, greater demand for residential space and environmental issues. One solution for these problems is the development of underground space, especially tunnelling. However, tunnel collapse causes significant damage, so it is important to understand the interactive behaviour of soil-structure-tunnelling in urban areas. This study uses a model test to investigate the behaviour of an embedded pile and the surrounding ground due to tunnelling in soft ground. Tunnelling is simulated by volume loss (VL), and soil deformation is observed according to VL using close range photogrammetry and image processing. These data are compared by 3D numerical analysis.