Use of laser scanning technology on the monitoring of slope failure

초록

The intensive rainfall occurred recent year causes severe impact on the human life in various ways. Increased vulnerability of landslide must be one of impact inducing the loss of human life and infrastructures. In consequence, a proper methods of monitoring and reinforcement need to be developed. A typical slope monitoring can be conducted by locally installed inclinometers and tiltmeters as well as moisture content measurement, for example, Time Domain Reflectometry, TDR. All of these instruments are independently installed. The decision of slope instability is made from the interrelated analysis of measured data from such instruments. This method of monitoring provides detailed and various types of information regarding the relative movement of soil layers and physical variation of soil properties. However, the fundamental limitation of such system lies on the locality of the instruments. Even with the installation of densely populated instruments, initial slip of slope cannot be detected because of progressive type of failure. The surface of slope failure by rainfall do not generated simultaneously. Initial erosion of soil particles and extension of rills must be incorporated during the failure process. Therefore, global type of monitoring system would be more beneficial than the locally installed monitoring system. In this study we developed a laser scanner based slope monitoring system for the laboratory tests. The scanner is designed and constructed for lab tests. The scanned data has geometric and radiometric information. The geometric data shows the general shape and failure process of slope. Use of the radiometric data shows identification of initial erosion and slip of slope. Generally the initial erosion of slope occurs with quite small amount of displacement which hardly can be detected by inclinometer or tiltmeter. Nevertheless, the variation of radiometric information successfully shows the occurrence of erosion and its process.