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Embankment dam deformation during earthquakes
SURFACE STRUCTURES:HYDRAULIC STRUCTURES
953196 Embankment dam deformation during earthquakes R. Chowdhury & D. W. Xu, in: Geotechnical engineering: emerging trends in design and practice, ed K.R. Saxena, (Balkema), 1994, pp 187-198. The design of earthquake-resistant embankments and earth dams is of great interest to geotecbnical engineers. Therefore, considerable efforts have been made to develop methods for assessing the capability of earth structures to resist earthquake shaking. Under static loading conditions, it is often considered sufficient to achieve a specified factor of safety based on limit equilibrium considerations. Deformations can be minimised effectively with good design followed by effective construction control. However, under earthquake loading, excessive permanent deformations may occur even if overall stability is maintained. A recent review of geoteehnical practice and advances with regard to earthquake stability of embankments over the last 25 years (Marcuson et al. 1992) reveals that Newmark-type approaches (Newmark 1965) and the Seed-Idriss-Lee apaproacb (Seed 1979) are still considered to be the best available for studying the response of embankments to earthquakes. (from Authors)
953197 Tailings dams - some aspects of their design and construction A. D. M. Penman, in: Geotechnical engineering: emerging trends in design and practice, ed K.R. Saxena, (Balkema), 1994, pp 247-277. There are various ways of dealing with tailings. Usually they are simply stored, but sometimes they can be used and old stored tailings are sometimes reworked because they still contain some metal which can be extracted by the modern, more efficient processing plant. The simplest and usually cheapest method of storage takes the form of a lagoon into which the slurry or chemical fluid can be discharged. Sometimes a natural hollow can be found, but usually a lagoon is formed by a dam placed across a dry valley or arranged along a hillside so as to retain a lagoon. Dams built for this purpose are referred to as tailings dams. They can take a form very similar to that of an embankment dam designed to impound water and made from borrowed fill, but more usually, and particularly for the storage of tailings from metal mining, they are constructed from the tailings themselves. As with water-retaining dams, each tailings dam is an individual, dependent for its detailed design on the site conditions, the type and rate of delivery of the tailings, availability of other waste materials from the mining or industrial processes, climatic conditions, and other factors. Despite individual details, there are overall patterns discussed here in general terms. (from Author)
953198 The need for redundancy in seepage control-embankment dams and their foundations D. E. Kleiner, in: Geotechnicai engineering: emerging trends in design and practice, ed K.R. Saxena, (Balkema), 1994, pp 337-352. Defining 'redundant' as: 'Designing, incorporation, and including physical and human processes into analysis, design, and construction in such a way that if one element, whether physical or human, fails to function or fails to function in the way intended, other elements take over in such a way that the structure will still function essentially as intended'. This paper presents the theme of redundancy as related to the control of seepage in embankment dams and their foundations. (from Author)
131A
953199 Seepage analysis of Tarbela dam (Pakistan) using finite element method Y. Honjo, Pham Huy Giao & P. A. Naushahi, in: Prediction versus performance in geotechnical engineering. Proc. symposium, Bangkok, 1992, ed A.S. Balasubramaniam & & others, (Balkema), 1994, pp 219-236. The performance data on seepage control of Tarbela Dam, which was completed in 1975 in Pakistan, is analyzed using Saturated-Unsaturated Seepage Flow Finite Element analysis based on the Invariant Mesh technique. Computer code UNSAF2D has been used for the analysis. The analysis is done for the various stages of reservoir filling, depleting and various conditions of sedimentation in the reservoir. The comparison, generally, shows a good agreement between calculated and observed values, one of the pronounced feature of the Tarbela dam is its very wide upstream impervious blanket. The purpose of the construction of this blanket was to control the seepage and the upfift pressure of the dam built on the very thick alluvium deposit of the Indus river. The calculated results explain the function of this upstream blanket, and also its change of permeability characteristics with time due to accumulation of large amount of sediment on it. (Authors)
Hydraulic structures 953200 Underwater acoustics for bridge building R. A. Hazelwood, Hydrographic Journal, 74, 1994, pp 3-6. The 5.5 km long East Bridge will complete the road crossing of the Danish Storebaelt. Its foundations were formed by a 4 m x 4 m vibrating plate compactor which was positioned by acoustics over 7984 different targets. Long baseline acoustic positioning gave the necessary high accuracy and speed in adverse conditions. The fast moving waters have very variable temperature and salinity. The consequent ray bending is tidally variable, a problem addressed in the design phase by modelling the ray paths. The acoustic transponders were protected from high vibration level of the compactor by purpose built isolating frames with non-linear compliance characteristics. (Author)
953201 Limit states design appfied to bridge abutment walls G. E. Bauer, in: Prediction versus performance in geotechnical engineering. Proc. symposium, Bangkok, 1992, ed A.S. Balasubramaniam & & others, (Balkema), 1994, pp 271-277. This paper discusses the concept of applying the ultimate limit states (mainly instability against sliding, bearing capacity and overturning) and the serviceability limit states (mainly total and differential movements) analyses to the design of bridge abutments founded on spread footings. This concept of applying reduced strength parameters and factored loads in geotechnicai engineering is incorporated in design codes in Canada. A typical example for a bridge abutment founded on spread footings is given in this paper, and the predicted performance is compared to the actual behaviour of the structure. (Author)
953202 The performance of hydraulic structures predicted from model tests G. E. Bauer, in: Prediction versus performance in geotechnical engineering. Proc. symposium, Bangkok, 1992, ed A.S. Balasubramaniam & & others, (Balkema), 1994, pp 249-256. Most cofferdams are constructed with an adequate factor of safety regarding the structural components. Therefore failure can occur only due to piping or bottom heave within the excavation caused by water seeping from the higher outside to
953196 Embankment dam deformation during earthquakes R. Chowdhury & D. W. Xu, in: Geotechnical engineering: emerging trends in design and practice, ed K.R. Saxena, (Balkema), 1994, pp 187-198. The design of earthquake-resistant embankments and earth dams is of great interest to geotecbnical engineers. Therefore, considerable efforts have been made to develop methods for assessing the capability of earth structures to resist earthquake shaking. Under static loading conditions, it is often considered sufficient to achieve a specified factor of safety based on limit equilibrium considerations. Deformations can be minimised effectively with good design followed by effective construction control. However, under earthquake loading, excessive permanent deformations may occur even if overall stability is maintained. A recent review of geoteehnical practice and advances with regard to earthquake stability of embankments over the last 25 years (Marcuson et al. 1992) reveals that Newmark-type approaches (Newmark 1965) and the Seed-Idriss-Lee apaproacb (Seed 1979) are still considered to be the best available for studying the response of embankments to earthquakes. (from Authors)
953197 Tailings dams - some aspects of their design and construction A. D. M. Penman, in: Geotechnical engineering: emerging trends in design and practice, ed K.R. Saxena, (Balkema), 1994, pp 247-277. There are various ways of dealing with tailings. Usually they are simply stored, but sometimes they can be used and old stored tailings are sometimes reworked because they still contain some metal which can be extracted by the modern, more efficient processing plant. The simplest and usually cheapest method of storage takes the form of a lagoon into which the slurry or chemical fluid can be discharged. Sometimes a natural hollow can be found, but usually a lagoon is formed by a dam placed across a dry valley or arranged along a hillside so as to retain a lagoon. Dams built for this purpose are referred to as tailings dams. They can take a form very similar to that of an embankment dam designed to impound water and made from borrowed fill, but more usually, and particularly for the storage of tailings from metal mining, they are constructed from the tailings themselves. As with water-retaining dams, each tailings dam is an individual, dependent for its detailed design on the site conditions, the type and rate of delivery of the tailings, availability of other waste materials from the mining or industrial processes, climatic conditions, and other factors. Despite individual details, there are overall patterns discussed here in general terms. (from Author)
953198 The need for redundancy in seepage control-embankment dams and their foundations D. E. Kleiner, in: Geotechnicai engineering: emerging trends in design and practice, ed K.R. Saxena, (Balkema), 1994, pp 337-352. Defining 'redundant' as: 'Designing, incorporation, and including physical and human processes into analysis, design, and construction in such a way that if one element, whether physical or human, fails to function or fails to function in the way intended, other elements take over in such a way that the structure will still function essentially as intended'. This paper presents the theme of redundancy as related to the control of seepage in embankment dams and their foundations. (from Author)
131A
953199 Seepage analysis of Tarbela dam (Pakistan) using finite element method Y. Honjo, Pham Huy Giao & P. A. Naushahi, in: Prediction versus performance in geotechnical engineering. Proc. symposium, Bangkok, 1992, ed A.S. Balasubramaniam & & others, (Balkema), 1994, pp 219-236. The performance data on seepage control of Tarbela Dam, which was completed in 1975 in Pakistan, is analyzed using Saturated-Unsaturated Seepage Flow Finite Element analysis based on the Invariant Mesh technique. Computer code UNSAF2D has been used for the analysis. The analysis is done for the various stages of reservoir filling, depleting and various conditions of sedimentation in the reservoir. The comparison, generally, shows a good agreement between calculated and observed values, one of the pronounced feature of the Tarbela dam is its very wide upstream impervious blanket. The purpose of the construction of this blanket was to control the seepage and the upfift pressure of the dam built on the very thick alluvium deposit of the Indus river. The calculated results explain the function of this upstream blanket, and also its change of permeability characteristics with time due to accumulation of large amount of sediment on it. (Authors)
Hydraulic structures 953200 Underwater acoustics for bridge building R. A. Hazelwood, Hydrographic Journal, 74, 1994, pp 3-6. The 5.5 km long East Bridge will complete the road crossing of the Danish Storebaelt. Its foundations were formed by a 4 m x 4 m vibrating plate compactor which was positioned by acoustics over 7984 different targets. Long baseline acoustic positioning gave the necessary high accuracy and speed in adverse conditions. The fast moving waters have very variable temperature and salinity. The consequent ray bending is tidally variable, a problem addressed in the design phase by modelling the ray paths. The acoustic transponders were protected from high vibration level of the compactor by purpose built isolating frames with non-linear compliance characteristics. (Author)
953201 Limit states design appfied to bridge abutment walls G. E. Bauer, in: Prediction versus performance in geotechnical engineering. Proc. symposium, Bangkok, 1992, ed A.S. Balasubramaniam & & others, (Balkema), 1994, pp 271-277. This paper discusses the concept of applying the ultimate limit states (mainly instability against sliding, bearing capacity and overturning) and the serviceability limit states (mainly total and differential movements) analyses to the design of bridge abutments founded on spread footings. This concept of applying reduced strength parameters and factored loads in geotechnicai engineering is incorporated in design codes in Canada. A typical example for a bridge abutment founded on spread footings is given in this paper, and the predicted performance is compared to the actual behaviour of the structure. (Author)
953202 The performance of hydraulic structures predicted from model tests G. E. Bauer, in: Prediction versus performance in geotechnical engineering. Proc. symposium, Bangkok, 1992, ed A.S. Balasubramaniam & & others, (Balkema), 1994, pp 249-256. Most cofferdams are constructed with an adequate factor of safety regarding the structural components. Therefore failure can occur only due to piping or bottom heave within the excavation caused by water seeping from the higher outside to