A large number of debris flows occurred simultaneously at around 8:30 to 8:50 a.m.on July 27,2011,at the center of Seoul,Korea.This area is located in the southern part of Seoul and is a densely populated district.As ...A large number of debris flows occurred simultaneously at around 8:30 to 8:50 a.m.on July 27,2011,at the center of Seoul,Korea.This area is located in the southern part of Seoul and is a densely populated district.As a result of the debris flow event,16 people were killed,30 houses were buried,and 116 houses were damaged around Umyeon Mountain,a relatively small mountain with a height of 312.6 m.Since the debris flow event,field investigations on the initiation and transportation zones of debris flows have been carried out.Rainfall data were collected from the automatic weather stations(AWSs) which are operated by the Korea Meteorological Administration(KMA).Video files recorded by residents were also acquired and used to analyze the flow characteristics of the debris flow.Field investigation shows that about 40 debris flows occurred around Umyeon Mountain and most of the debris flows were initiated by small slope failures.The effects of the precipitation that triggered the debris flows were analyzed as well.A landslide hazard map which considers slope gradient and aspect,strength of soil,hazard record,rainfall conditions,and vegetation,was constructed and compared with the initiation zones of debris flows.展开更多
In this paper, properties of new kind of modified bitumen are presented. Bituminous binder was modified with mix modification using polymer and additive of crumb rubber. Terminal blend process at the refinery was appl...In this paper, properties of new kind of modified bitumen are presented. Bituminous binder was modified with mix modification using polymer and additive of crumb rubber. Terminal blend process at the refinery was applied to produce the mixed modified binder. Laboratory tests were focused on the characterization of the properties of 45/80-55 CR binder with comparison to reference 50/70 and conventional polymer modified 45/80-55 bitumen. Based on conventional binder tests such as penetration, softening point and Fraass breaking point as well as BBR （bending beam rheometer） and DSR （dynamic shear rheometer） tests, rheological properties were investigated. For determination of stability of the polymer and crumb rubber, modified bitumen tube testing method was used. Based on the results analysis, improvement of the viscoelastic properties of polymer and crumb rubber modified bitumen was observed. Conventional properties and stability tests showed that it is possible to pass standard requirements for polymer modified bitumen. Mixed modification and terminal blend allow to use crumb rubber as a modifier with elimination of the separation of crumb rubber during transportation and storage at high temperature. In this paper, experience from filed sections with use of the asphalt mixture with new kind of modified bitumen is presented.展开更多
Based on observational analyses and on-site ground and aerial damage surveys, this work aims to reveal the weather phenomena--especially the wind situation--when Oriental Star capsized in the Yangtze River on June 1, ...Based on observational analyses and on-site ground and aerial damage surveys, this work aims to reveal the weather phenomena--especially the wind situation--when Oriental Star capsized in the Yangtze River on June 1, 2015. Results demonstrate that the cruise ship capsized when it encountered strong winds at speeds of at least 31 m s ^-1 near the apex of a bow echo embedded in a squall line. As suggested by the fallen trees within a 2-kin radius around the wreck location, such strong winds were likely caused by microburst straight-line wind and/or embedded small vortices, rather than tomadoes.展开更多
基金supported by the Basic Science Research Program through the National Research Foundation of Korea (NRF) funded by the Ministry of Education,Science and Technology (2012014940)supported by a grant(Code#’08 RTIP B01-01) from the Regional Technology Innovation Program (RTIP)funded by the Ministry of Land Transport and Maritime Affairs of the Korean government
文摘A large number of debris flows occurred simultaneously at around 8:30 to 8:50 a.m.on July 27,2011,at the center of Seoul,Korea.This area is located in the southern part of Seoul and is a densely populated district.As a result of the debris flow event,16 people were killed,30 houses were buried,and 116 houses were damaged around Umyeon Mountain,a relatively small mountain with a height of 312.6 m.Since the debris flow event,field investigations on the initiation and transportation zones of debris flows have been carried out.Rainfall data were collected from the automatic weather stations(AWSs) which are operated by the Korea Meteorological Administration(KMA).Video files recorded by residents were also acquired and used to analyze the flow characteristics of the debris flow.Field investigation shows that about 40 debris flows occurred around Umyeon Mountain and most of the debris flows were initiated by small slope failures.The effects of the precipitation that triggered the debris flows were analyzed as well.A landslide hazard map which considers slope gradient and aspect,strength of soil,hazard record,rainfall conditions,and vegetation,was constructed and compared with the initiation zones of debris flows.
文摘In this paper, properties of new kind of modified bitumen are presented. Bituminous binder was modified with mix modification using polymer and additive of crumb rubber. Terminal blend process at the refinery was applied to produce the mixed modified binder. Laboratory tests were focused on the characterization of the properties of 45/80-55 CR binder with comparison to reference 50/70 and conventional polymer modified 45/80-55 bitumen. Based on conventional binder tests such as penetration, softening point and Fraass breaking point as well as BBR （bending beam rheometer） and DSR （dynamic shear rheometer） tests, rheological properties were investigated. For determination of stability of the polymer and crumb rubber, modified bitumen tube testing method was used. Based on the results analysis, improvement of the viscoelastic properties of polymer and crumb rubber modified bitumen was observed. Conventional properties and stability tests showed that it is possible to pass standard requirements for polymer modified bitumen. Mixed modification and terminal blend allow to use crumb rubber as a modifier with elimination of the separation of crumb rubber during transportation and storage at high temperature. In this paper, experience from filed sections with use of the asphalt mixture with new kind of modified bitumen is presented.
基金the Ministry of Science and Technology of China (2013CB430104)he National Natural Science Foundation of China (41425018, 4141101075, and 41375048)
文摘Based on observational analyses and on-site ground and aerial damage surveys, this work aims to reveal the weather phenomena--especially the wind situation--when Oriental Star capsized in the Yangtze River on June 1, 2015. Results demonstrate that the cruise ship capsized when it encountered strong winds at speeds of at least 31 m s ^-1 near the apex of a bow echo embedded in a squall line. As suggested by the fallen trees within a 2-kin radius around the wreck location, such strong winds were likely caused by microburst straight-line wind and/or embedded small vortices, rather than tomadoes.
