The Study of Risk Assessment of Shallow Collapse Disaster on Slope Land

• Main Authors: Chen, Chun-Wei, 陳俊瑋
• Other Authors: Chien, Lien-Kwei
• Format: Others
• Language: zh-TW
• Published: 2019
• Online Access: http://ndltd.ncl.edu.tw/handle/529k77

碩士 === 國立臺灣海洋大學 === 河海工程學系 === 107 === Taiwan is surrounded by the ocean and the plain area is small. With the population growth in the past, the demand for land development is increasing. To achieve the balance between the land utilization and demands, it must develop more slope lands. In addition, because of the climate change in recent year, the extreme rainfall frequently happened, such as rainfall strength and duration. Moreover, it caused the collapse of Taiwan’s mountainous areas to increase the risk of neighboring slope communities and roads. In the past, domestic and foreign research focused on the hazard for slope land disasters, and less risk assessment of the overall risk of slope disasters. Therefore, this study is adopted a definition of disaster risk is function of hazard and vulnerability by the UNISDR (United Nations International Strategy for Disaster Reduction). In addition to the spatial distribution of slope disaster risk, the research scale uses village level to explore the risk of shallow collapse in the slopes of Keelung City. In this study, the hydrological model - topographical index model of the topographical characteristics of the basin area is used to calculate the relationship between the topography and the groundwater level. And the stability analysis of the infinite slope is used to investigate the influence of different groundwater level heights on the slope land stability of the study area. The slope land collapse factor is summarized as the hazard aspect of the study. Meanwhile, the research area is affected by the vulnerability of the slope land disaster, with the social, economic, environmental, physical aspects, and the resilience is added to vulnerability index. Vulnerability factors such as vulnerable population, population density, road density, disaster record, household income, disaster temporary shelters were selected. The vulnerability analysis was performed using the Pareto Ranking method. The calculated hazard map and the vulnerability map are combined with the risk matrix to evaluate the slope land risk level and use the Geographic Information System (GIS) to display the risk map. Finally, the risk assessment model for shallow collapse disasters on slope land is established. The risk assessment of shallow collapse on slope land shows that most of the villages are concentrated in the metropolitan area of Renai and Zhongzheng District in Keelung City, while others are in Qidu, Zhongshan and Anle District in the face of the impact of sloping land disasters. Due to their vulnerability are larger than other area, which leads to the situation that the risk level of these villages is "high" to "very high". This study explores the risk of shallow collapse on slope land from the perspective of risk. Compared with the past, it only discusses the hazard orientation of slope land, and can better reflect the relative risk each region. It can effectively focus on high-risk areas for decision-making units in regional risk management.