The goal of this study is to determine the geometrical and geotechnical characteristics of landslides under various geological conditions using detailed field surveys, laboratory soil tests and precipitation records. ...The goal of this study is to determine the geometrical and geotechnical characteristics of landslides under various geological conditions using detailed field surveys, laboratory soil tests and precipitation records. Three study areas are selected to consider different rocks, including gneiss in Jangheung, granite in Sangju and sedimentary rocks in Pohang, South Korea. Many landslides have occurred in these three areas during the rainy season.Precipitation records indicate that landslides occurring in the gneiss area of Jangheung and granite area of Sangju may be influenced by the hourly rainfall intensity rather than cumulative rainfall.However, landslides occurring in the sedimentary rock area of Pohang may be influenced by hourly rainfall intensity and cumulative rainfall. To investigate the factors that influence these types of landslides, a detailed landslide survey was performed and a series of laboratory soil tests were conducted.According to the detailed field survey, most landslides occurred on the flanks of mountain slopes, and the slope inclination where they occurred mostly ranged from 26 to 30 degrees, regardless of the geological conditions. The landslide in the gneiss area of Jangheung is larger than the landslides in the granite area of Sangju and sedimentary rock area of Pohang.Particularly, the landslide in the sedimentary rock area is shorter and shallower than the landslides in the gneiss and granite areas. Thus, the shape and size of the landslide are clearly related to the geological conditions. According to the integrated soil property and landslide occurrence analyses results, the average dry unit weight of the soils from the landslide sites is smaller than that of the soils obtained from the nonlandslide site. The average coefficient of permeability of soils obtained from the landslide sites is greater than that of soils obtained from the non-landslide sites with the same geology. These results indicate that the soils from the landslide sites are more poorly graded or looser than the soils from the non-landslide sites.展开更多
Artificial groundwater recharge is a promising technology to address the threat to water supply posed by climate change.An artificial groundwater recharge project,which directs water from seasonal flash flooding into ...Artificial groundwater recharge is a promising technology to address the threat to water supply posed by climate change.An artificial groundwater recharge project,which directs water from seasonal flash flooding into a volcanic aquifer,is being conducted展开更多
The toxic effects of the composites of Fe^0 and Cu^0 with different percentages of CNTs were examined based on the activity of bacterial bioluminescence and seed germination. In terms of the EC50 values, the toxic eff...The toxic effects of the composites of Fe^0 and Cu^0 with different percentages of CNTs were examined based on the activity of bacterial bioluminescence and seed germination. In terms of the EC50 values, the toxic effects of Cu^0 on bacterial bioluminescence and seed germination were approximately 2 and 180 times greater than that of Fe^0, respectively. The toxicity increased with increasing CNT content in the Cu-CNT mixtures for both organisms,whereas opposite results were observed with Fe-CNT mixtures. The mean toxic effects of Cu-CNT（6%） were approximately 1.3–1.4 times greater than that of Cu-CNT（0%）, whereas the toxic effects of Fe-CNT（6%） were approximately 2.1–2.5 times lower than that of Fe-CNT（0%） for both the bioluminescence activity and seed germination. The causes of this phenomenon are unclear at this point. More research will be needed to elucidate the mechanism of the toxicity of nano-mixture materials and the causes of the different patterns of toxicity with Cu-and Fe-CNT mixtures.展开更多
基金supported by the Basic Research Project (Grant No. 15-3413) of the Korea Institute of Geoscience and Mineral Resources (KIGAM)funded by the Ministry of Science, ICT and Future Planning of Korea
文摘The goal of this study is to determine the geometrical and geotechnical characteristics of landslides under various geological conditions using detailed field surveys, laboratory soil tests and precipitation records. Three study areas are selected to consider different rocks, including gneiss in Jangheung, granite in Sangju and sedimentary rocks in Pohang, South Korea. Many landslides have occurred in these three areas during the rainy season.Precipitation records indicate that landslides occurring in the gneiss area of Jangheung and granite area of Sangju may be influenced by the hourly rainfall intensity rather than cumulative rainfall.However, landslides occurring in the sedimentary rock area of Pohang may be influenced by hourly rainfall intensity and cumulative rainfall. To investigate the factors that influence these types of landslides, a detailed landslide survey was performed and a series of laboratory soil tests were conducted.According to the detailed field survey, most landslides occurred on the flanks of mountain slopes, and the slope inclination where they occurred mostly ranged from 26 to 30 degrees, regardless of the geological conditions. The landslide in the gneiss area of Jangheung is larger than the landslides in the granite area of Sangju and sedimentary rock area of Pohang.Particularly, the landslide in the sedimentary rock area is shorter and shallower than the landslides in the gneiss and granite areas. Thus, the shape and size of the landslide are clearly related to the geological conditions. According to the integrated soil property and landslide occurrence analyses results, the average dry unit weight of the soils from the landslide sites is smaller than that of the soils obtained from the nonlandslide site. The average coefficient of permeability of soils obtained from the landslide sites is greater than that of soils obtained from the non-landslide sites with the same geology. These results indicate that the soils from the landslide sites are more poorly graded or looser than the soils from the non-landslide sites.
文摘Artificial groundwater recharge is a promising technology to address the threat to water supply posed by climate change.An artificial groundwater recharge project,which directs water from seasonal flash flooding into a volcanic aquifer,is being conducted
基金supported by the 2017 Yeungnam University Research Grant
文摘The toxic effects of the composites of Fe^0 and Cu^0 with different percentages of CNTs were examined based on the activity of bacterial bioluminescence and seed germination. In terms of the EC50 values, the toxic effects of Cu^0 on bacterial bioluminescence and seed germination were approximately 2 and 180 times greater than that of Fe^0, respectively. The toxicity increased with increasing CNT content in the Cu-CNT mixtures for both organisms,whereas opposite results were observed with Fe-CNT mixtures. The mean toxic effects of Cu-CNT（6%） were approximately 1.3–1.4 times greater than that of Cu-CNT（0%）, whereas the toxic effects of Fe-CNT（6%） were approximately 2.1–2.5 times lower than that of Fe-CNT（0%） for both the bioluminescence activity and seed germination. The causes of this phenomenon are unclear at this point. More research will be needed to elucidate the mechanism of the toxicity of nano-mixture materials and the causes of the different patterns of toxicity with Cu-and Fe-CNT mixtures.
