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Civil and geotechnical engineering in society — Ethical aspects and future prospects
Published in Iacint Manoliu, Ion Antonescu, Nicoleta Rădulescu, Geotechnical Engineering Education and Training, 2020
Most individuals, living in a modern industrial state, are not aware how much it is the achievement of civil engineering that so many people can live comfortable lives in such a relatively small area. For the basic needs of society, civil engineers build water supply and sewage facilities, they construct apartment- and office buildings, factories, as well as storage facilities and silos. For the distribution of goods they build roads and railways, market halls, department stores, and supermarkets. For the education of our children they construct all kinds of schools, and, to an ever increasing extent, trade schools, colleges, and universities for the professional education, because more and more people strive for higher education to enrich their lives. Civil engineers erect the facilities to obtain natural resources, they build power plants for energy production, hospitals where people hope to be cured, sport facilities for bodily fitness — as well as waste water purification plants and refuse deposits in order for society not to be suffocated by the waste created by industrial production and by every-day-living, and not to cause irreparable damage to the environment. Furthermore, civil- and geotechnical engineers minimize natural hazards (e.g. by landslide stabilization, flood protection, avalanche and mudflow protection, design of earthquake resistant structures, etc.).
Sediments and Sedimentary Rocks
Published in Dexter Perkins, Kevin R. Henke, Adam C. Simon, Lance D. Yarbrough, Earth Materials, 2019
Dexter Perkins, Kevin R. Henke, Adam C. Simon, Lance D. Yarbrough
Flows—including creep, earthflows, and debris flows—move more slowly than slides and falls. Creep, the slowest kind of mass movement, may continue for extended times on any slope. Some results of creep are bulging hillsides, bent trees that have curved to grow vertically, and inclined telephone poles. Earthflows (involving mostly soil) and debris flows (involving soil, rock, and organic debris) move faster than creep, travelling on the order of kilometers/hour. Most earthflows and debris flows remain localized on a single slope and, in any kind of flow, if the flowing material is supersaturated with water, it moves faster than if dry. Mudflows, involving water-saturated fine muds, for example, move at velocities up to several kilometers/hour. Mudflows usually result from heavy rains, but melting snow on erupting volcanoes may produce them as well. Once mudflows start to move, they may engulf valleys. They can travel long distances and so are potentially very dangerous to people.
Mass movement
Published in Richard J. Chorley, Stanley A. Schumm, David E. Sugden, Geomorphology, 2019
Richard J. Chorley, Stanley A. Schumm, David E. Sugden
A mudflow is the result of a high water content and flowage in a preexisting valley or depression. A mudflow or debris flow can move at a high velocity and be destructive. For example, during the years 1962–71 twenty-three people in the greater Los Angeles area were killed as a result of debris flows that probably originated as soil slips. Soil slips are shallow failures of alluvial soil and ravine fill (Campbell, 1975). The debris flows are generated when the initial slipping movement of slabs of soil and wedges of ravine fill cause reconstitution of the sliding masses into viscous, debris-laden mud, which then flows down available drainage courses, accelerating to avalanche speed until reaching gradients gentle enough for deposition. Soil slips require a combination of three conditions: (1) a mantle of colluvial soil or a wedge of colluvial ravine fill; (2) a steep slope; and (3) soil moisture sufficient to permit flowage. In southern California the most common range of slopes for soil slips that give rise to destructive debris flows is from about 45° to about 27°. The steeper slopes generally do not have a continuous mantle of soil and the slips cannot take place. On the gentler slopes of less than 27° the few debris flows that form do not accelerate downslope.
Predictive modeling and analysis of runout distance of physical mudflows based on a discrete element method
Published in Journal of the Chinese Institute of Engineers, 2021
Jian Ye, Gordon G. D. Zhou, Jinfeng Liu
Mudflows are very viscous, hyper-concentrated sediment flows composed of materials (silt and/or clay) with a high degree of plasticity (Laigle and Coussot 1997). Submarine mudflows and debris flows are fine-grained, gravity-driven flows with approximately equal parts of water and solids by volume (Iverson 1997). Mudflows represent a special type of debris flow (Zhou et al. 2015). In mountainous areas, mudflows are usually triggered by exceptional combinations of rainfall, snowmelt, and/or volcanic eruptions Mudflows have destroyed villages, farmland, schools, factories, roads, and property, and have caused significant loss of life.