부산대학교 도서관

Collapse caused by heavy rain occurred in Seogwipo, Jeju. As the natural cliff collapsed, it damaged the Jeju Island's first-class ecological conservation area and urgently called for restoration. The collapse site is bordered by the coast and forms a very steep slope of 65 meters and at that time a small new construction was built on the upper slope of the natural cliff. Geology of Jeju Island belongs to the Seogwipo stratum in Paleocene, Late Tertiary and volcanic debris in Plistocene, Quarternary. And geological composition of this local area is Basaltic-Trachytic Andesite, Tradhyte, Traghytic Basalt from the lower part. Trachytic rock with horizontal and vertical joint has orbicular weathered and large scale roch fall. Trachytic Basalt with crinkers, veciculars and sheeting joint and systematic vertical joint was led rock fall. For Low-altitude proximity to the target area was used a multi-copter unmanned aerial vehicle and full HD with PHANTOM 2 VISION+. On the basis of on-site drilling investigation and face mapping on the excavation surface, a slope stability analysis was conducted through a stereo projection analysis, the limit equilibrium analysis and a finite element analysis. Stability analysis shows that the main cause of slope failure is defacts of geological factors and construction of new structures. The method of high-strength tension net, which has been chosen as the method to counter the slope stabilization, is evaluated as the most suitable method for restoring the slope collapsed in certain geological conditions and ecological environment, and is currently being successfully maintained.