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Engineering Planning and Design
Published in Graeme Dandy, David Walker, Trevor Daniell, Robert Warner, Planning and Design of Engineering Systems, 2018
Graeme Dandy, David Walker, Trevor Daniell, Robert Warner
Design work for the project would be needed to determine the details of any new components, or modifications to existing components. If, for example, it is decided that a new dam is to be constructed, design work becomes necessary to determine where it is to be sited, the size, shape and other details of the dam wall, and how it is to be keyed into the valley walls at the site. Before such design work can begin, it is necessary to identify and survey the possible sites and to obtain data on rainfall and runoff patterns, as well as relevant geological information. Careful planning is also needed to determine the sequence of steps for constructing the dam wall and other related components. The resulting construction plan for the dam will include activities such as providing access roads to the site, bringing in heavy equipment, excavating soil and rock, shaping and preparing the foundations, grouting unsound regions of bed rock, and progressive construction of the main wall. Design work is also needed for other related components of the delivery system such as pipes, pumping stations, holding tanks, and pressure tanks.
Reservoirs and Dams
Published in F.G.H. Blyth, M. H. de Freitas, A Geology for Engineers, 2017
F.G.H. Blyth, M. H. de Freitas
Valleys exist because weathering and erosion have been accentuated at their location; weathered, compressible foundations, and unstable slopes, must be expected near ground level. Stress relief is associated with uplift and erosion (p. 160), and with the excavation of foundations; it can markedly affect the frequency of jointing in a rock valley and the aperture of such fractures (see Grand Coulee Dam, p. 248). Valleys eroded at a time when their rivers were draining to a sea level that was lower than at present (p. 42) are likely to have become a site of deposition following the recovery of sea level to its present elevation. These buried valleys (q.v.) may contain thick sequences of weak, compressible sediment such as silt, peat and clay, interbedded with stronger deposits of sand and gravel. Glaciated valleys may contain till beneath their more recent alluvium.
Management Disposal Schemes
Published in Roland Pusch, Raymond N. Yong, Masashi Nakano, Geologic Disposal of Low- and Intermediate-Level Radioactive Waste, 2017
Roland Pusch, Raymond N. Yong, Masashi Nakano
Sedimentary soil originates from eroded soils and rocks and is often characterized by layering and lamination and strong granulometric variation with depth (Figures 5.2 and 5.3). Figure 5.2 shows schematically a typical cross section of eskers in present major river valleys in Scandinavia, North America, and other glaciated areas. The valleys were created by glaciers that dug out steep, major fracture zones to many meters depth, leaving dense moraine (till) that was later overfilled by glacial and postglacial sand and clay. Strong meltwater flow in the retreating glaciers eroded the till and deposited blocks, gravel, and sand material that built up the eskers. The meltwater in the retreating glacier eroded it and deposited sand and gravel over the postglacial clay, which often causes problems in the modern construction of buildings: too shallow geotechnical investigations may not reveal the clay, which can cause large irregular settlement and destruction of buildings founded on overlying sand and gravel. In general, postglacial and glacial clay that is not overconsolidated* is not suitable for constructing an on-ground repository.
Application of geospatial technologies in developing a dynamic landslide early warning system in a humanitarian context: the Rohingya refugee crisis in Cox’s Bazar, Bangladesh
Published in Geomatics, Natural Hazards and Risk, 2020
Bayes Ahmed, Md. Shahinoor Rahman, Peter Sammonds, Rahenul Islam, Kabir Uddin
A comprehensive landslide inventory map containing 432 locations for CBD was prepared that was randomly divided into two groups (Figure 3) – training set for model running, and testing set for model validation purposes. In CBD, the type of movement was predominantly found as ‘slides’ (rotational and translational), and the engineering soil was categorised as ‘earth slides’. The landslide factor maps are shown in Figure 7. The geology map (Figure 7(b)) was classified as beach and dune sand (csd), Bhuban formation (Miocene, Tb), Boka Bil formation (Neogene, Tbb), Dihing formation (Pleistocene and Pliocene, QTdi), Dihing and Dupi Tila formations undivided (QTdd), Dupi Tila formation (Pleistocene and Pliocene, QTdt), Girujan clay (Pleistocene and Neogene, QTg), Marsh clay and peat (ppc), Tipam Sandstone (Neogene, Tt), valley alluvium and colluvium (ava), and water (H2O). Boka Bil, Tipam, Dupi Tila, and Dhing formations are actually hilly deposits from the Tertiary period. Beach sand and valley formations are from the Quaternary period. Beach sand/tidal deposits are formed near the coast due to tidal actions and are dominated by silt/silt and clay. Valley deposits are formed due to erosional activities near the hilly region and are composed of sand, sandy clay, and silty clay (Brammer 2012).
On land-use and land-cover changes over Lidder Valley in changing environment
Published in Annals of GIS, 2018
Mohammd Rafiq, Anoop Kumar Mishra, Mohammad Suhail Meer
Lidder Valley is our study area which is located in Anantnag district of Jammu and Kashmir India and is shown in Figure 1. It is one of the major valleys of Kashmir which lies between the geographical coordinates of 33°4′ N–34°15′ N latitude and 75°5ʹ–75°32ʹ E longitude with an area of 1250 km2 approximately and is nearly 50 km long with complex topography. The area is located in the central Himalayan mountain range and corresponds to a precipitous mountainous terrain with the elevation ranges from 1500 to 5500 m above sea level. The Lidder River gives rise to Lidder Valley, originates from Kolahoi glacier in the vicinity of Sonamarg and runs southwards through an alpine meadow called Lidderwat, from which the river has got its name. The river flows through lush green mountains of fir with tourist attractions places situated on its banks. It flows from side to side to Pahalgam where it meets a major tributary (the east Lidder) from Sheshnag lake and runs westwards until it meets the Jhelum River at Gurnar Khanabal village of Anantnag. Lidder Valley is also famous pilgrimage destination and located in the southeastern part of the state of Jammu and Kashmir. It forms the major tributary to river Jhelum and occupies the valley’s largest glacier. The Lidder Valley holds largest share of economy of the state as the area is famous for tourism and pilgrimage. Also, the valley provides waters for agriculture, horticulture, drinking and electricity generation.
Hazard assessment and zoning of collapse along highways in China based on backward cloud algorithm
Published in Geomatics, Natural Hazards and Risk, 2019
The illustration of each index factor is as follows:Rock mass stress state, rock stratification and structure plans. These two factors are not suitable for large-scale regional hazard analysis although they play a key role in the collapse of one rock or one slope. Thus, they were not chosen into the index system in this research.Rock types. The influence of rock types on highway collapses is significant. Diverse lithologies are formed under different geological environments and geological structures. The rock mass is the material basis for the collapse. Qi et al. (2009) point out that a collapse is developed when rocks are significantly hard.Slope grade. Slope grade is a significant specific indicator of the environment of disaster. It is the result of the cooperation of geological tectonics and natural forces. Based on numerous samples, the number of collapses in different slope gradients that range from 0°–90° is distributed normally, and the average gradient value is approximately 55°.Distance to the valley. A gully is a deep ditch that is cut by running water, especially after a prolonged downpour. A valley is a low stretch of land between hills, especially the hills with a river traversing them. The analysis results of Xu et al. (2013) indicated that the occurrence of geological disasters on a slope is frequent when the area from a valley is near.Slope high. The same as slope grade, slope high also reflects the cooperation of geological tectonics and natural forces. While the correlation of slope grade and collapse is not quite clear as the calculation result shown in Section 2.2.2 in this paper. Therefore, slope high is not chosen into the assessment index system.Annual torrential rain days. Rainfall is one of the foremost inducing factors. Huang et al. (2012) and Liu (1998)’s research indicated that, in all indices of rainfall, a collapse is closely related to short-term heavy rainfall.Human factors. Artificially excavating slopes, mining, and building reservoirs are significant incentives for the collapse. This indicator is not considered in this article because of the road construction is an artificially disturbed for the slope, and because the construction of mining and reservoir is not applicable in large-scale regional analysis.